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To do this, you must have Adobe Acrobat® Reader (version 4 or higher) installed on your computer. This medical discussion paper will be useful to those seeking general information about the medical issue involved.
Each medical discussion paper is written by a recognized expert in the field, who has been recommended by the Tribunala€™s medical counsellors. A mixed hearing loss occurs when both a sensorineural and conductive hearing loss are present at the same time. According to the 1990 Noise and Hearing Loss Consensus Conference, a€?Noise Induced Hearing Loss (NIHL) results from damage to the ear from sounds of sufficient intensity and duration that a temporary or permanent sensorineural hearing loss is produced.
PTS refers to a permanent loss of sensorineural hearing which is the direct result of irreparable injury to the organ of Corti. The 4000 Hz a€?notcha€? or a€?dipa€? in sensorineural hearing has been a classic finding in NIHL over the years. Why the 4000 Hz frequency appears more affected than other frequencies continues to generate some controversy.
Individuals vary in their susceptibility to noise and the damage it may cause to the cochlea. Of interest, one universal finding is that on average hearing threshold levels (HTLs) in the right ear are better than the left ear by about 1dB.
Whether one ear is more resilient to noise in the same individual (the so- called a€?tough vs. Please remember that when an asymmetric sensorineural hearing loss exists steps often need to be taken to exclude pathologic causes (i.e. The following statements tend to reflect what is agreed upon by the majority of scientists and physicians who deal with NIHL. Noise induced hearing loss (NIHL) may produce a temporary threshold shift (TTS), permanent threshold shift (PTS) or a combination of both. A PTS is caused by destruction of certain inner ear structures that cannot be replaced or repaired. The amount of hearing loss produced from a given noise exposure varies from person to person. NIHL initially affects higher frequency hearing (3-6 kHz range, for nearly all occupational exposures) than those frequencies essential for communication (i.e. Daily noise exposure (8hrs) > 90 dB for over 5 years (or equivalent) causes varying degrees of hearing loss in susceptible individuals. NIHL is a decelerating process; the largest changes occur in the early years with progressively smaller changes in the later years (so-called Corso's theorem).
NIHL first affects hearing in the 3-6 kHz range, for nearly all occupational exposures; the lower frequencies are less affected.
Once the exposure to noise is discontinued, there is no substantial further worsening of hearing as a result of noise unless other causes occur. Continuous noise exposure over the years is more damaging than interrupted exposure to noise which permits the ear to have a rest period. The pathologic basis for presbycusis appears to be one of gradual devascularization of the cochlea and loss of functioning hair cells. Clinically hearing loss from presbycusis appears to be an accelerating process unlike hearing loss in NIHL. Unfortunately, there is no specific treatment available that will prevent age related hearing loss at present. In the adjudication process of an occupational NIHL claim it is often difficult to separate the total amount of hearing loss from noise and age related change. For example, not everyone as they age will experience age-related presbycutic change (changes from presbycusis are variable with some individuals experiencing greater degrees of age related change than others).
Moreover, exposure to high level noise early on may produce hearing loss more rapidly than aging such that the aging process has a negligible effect (i.e.
The effects of noise exposure and aging on hearing when not combined are reasonably well-understood. Although it seems logical to a€?subtracta€? the age-related effects from the total hearing loss in order to quantitate the amount of hearing loss due to noise, this is really quite simplistic when one considers that aging effects and noise exposure effects can at times be practically indistinguishable for the most part audiometrically. Because compensation claims have required some consideration of presbycusis and its role in the total hearing loss of an individual various correction factors have been applied. Dobiea€™s theorem states that the total hearing loss from noise and age are essentially additive (this is the theory put into practice when a standard correction factor for age after 60 years is applied in the Province of Ontario). Corsoa€™s theorem on the other hand states that any correction for age should be based on a variable ratio (as individuals age the assumption is that the effects of presbycusis variably accelerate by decade).
Nevertheless the quantification of hearing loss attributable to age when occupational NIHL is present is really quite a complex phenomenon.
This is an inner ear disorder characterized by episodes of vertigo (an illusion of movement) lasting minutes to hours, fluctuating hearing loss and tinnitus (unwanted head noise). Usually one ear is involved initially although over time the other ear becomes affected in nearly 50% of cases.
Treatment is medical in most cases involving a low salt diet and diuretics and vestibular sedatives. Otosclerosis usually results in a conductive hearing loss from stapes footplate fixation due to new bone growth in this area. The diagnosis of cochlear otosclerosis is usually made when a family history of otosclerosis exists and other rare causes for a chronic progressive loss can be excluded. Although no medical treatment can ever reverse the sensorineural hearing loss, treatment with oral sodium fluoride may minimize and possibly stabilize an individuala€™s hearing. Physical injury to the ear is usually the result of blunt trauma in the circumstances of a significant head injury.
When physical trauma is severe enough to cause a temporal bone fracture (the temporal bone is the larger part of the skull bone that houses all the structures of the ear), two types of fractures occur; longitudinal and transverse.
In general terms longitudinal fractures are much more common and tend to result in a fracture line through the roof of the middle ear and ear canal. Transverse fractures of the temporal bone occur when the fracture lines run directly through the hard bone of the otic capsule. Ototoxicity is defined as the tendency of certain substances to cause functional impairment and cellular damage to the tissues of the inner ear, especially to the cochlea and the vestibular apparatus.
Aminoglycoside antibiotics are powerful weapons in the treatment of certain bacterial infections. Antimalarial drugs such as quinine and chloroquin unfortunately have ototoxicity as a side effect if taken in excess.
This is a pathologic misnomer since this tumour is strictly a schwannoma of the vestibular nerve.
Although benign this tumour has serious health implications for the patient and is sought for by otolaryngologists when there is an undiagnosed asymmetry in the hearing.
This diagnosis is given to the individual who experiences a sudden hearing loss in one ear. An individual's threshold hearing to pure tones at different frequencies (250 - 8000 Hz) is performed. Air conduction (AC) thresholds are delivered via headphones and the individual is asked to respond to the sound of the lowest intensity (in dB) they hear at the frequency being tested. The pure tone audiogram forms the basis for assessing if an individual qualifies for Workplace Safety and Insurance Board (WSIB) benefits in the Province of Ontario. Complex words with equal emphasis on both syllables (so called spondaic words such as a€?hotdoga€?, a€?uptowna€?, a€?baseballa€? etc.) are given an individual at the lowest intensity they can hear. A list of phonetically balanced single syllable words (these are words commonly found in the English language in everyday speech such as a€?fata€?, a€?asa€?, a€?doora€? etc.) are presented to an individual at 40 dB above their speech reception threshold (SRT) in the ear being tested.
In this test a probe is placed into the ear canal that both emits a sound and can vary pressure within the canal which causes the ear drum to move.
This tells whether the pressure in the middle ear is within normal limits and provides some indirect measurement of Eustachian tube function. Stiffening of the ear drum from loud noise occurs when the stapedius muscle contracts in the middle ear. Absent stapedial reflexes are usually seen in middle ear pathology such as otitis media with effusion or otosclerosis. If one measures how the ear drum moves when pressure is changed in the external ear canal from negative to positive a series of curves can be attained.
The ability to measure minute electrical potentials following sound stimulation of the cochlea (i.e.
Electrocochleography (ECoG) - This test measures electrical activity in the cochlea during the first 2 msec of cochlear stimulation. Auditory Brainstem Response (ABR) - This term is synonymous with the term brainstem evoked potential (BEP) or the brainstem evoked response audiogram (BERA). Threshold Evoked Potentials (TEP) - These electrical waveforms are usually identified between 50 - 200 msec following cochlear stimulation and are thought to represent cortical pathways of electrical activity. If AC thresholds are greater than BC thresholds this usually implies there is a conductive component to hearing loss from pathology involving the external or middle ear. If BC thresholds are greater than AC thresholds this would typically suggest an exaggerated hearing loss or malingering.
In its classic presentation a notched sensorineural hearing loss is noted at 4000 Hz that should be relatively symmetric. Age related hearing loss typically presents with a bilateral symmetrical high frequency sensorineural hearing loss.
There are often numerous discrepancies noted such as the presence of acoustic reflexes at levels below volunteered pure tone thresholds, discrepancies between volunteered pure tone average and speech reception thresholds etc. Subjective tinnitus can only be appreciated by the affected individual, is usually associated with a sensorineural hearing loss of some type and is the most common type noted.
Objective tinnitus, on the other hand, is quite rare but by definition is a noise that can be appreciated by an observer. Regardless of cause tinnitus can be quite disturbing for many individuals and can certainly affect their well-being. Treatment for tinnitus includes the use of more pleasurable competing background noise (i.e. The individual affected has undergone treatments to try to alleviate their perceived unwanted head noise (i.e.
Evidence to support a personality change or a sleep disorder as a result of the tinnitus. Hyperacusis is a curious phenomenon where an individual describes an uncomfortable, sometimes painful hypersensitivity to sounds that would be normally well tolerated in daily life. Treatment usually requires the gradual introduction of increasing sound intensity that becomes better tolerated with time. American Academy of Otolaryngology-Head and Neck Surgery Foundation Subcommittee on the Medical Aspects of Noise.
American Academy of Otolaryngology-Head and Neck Surgery Foundation: Guide for Conservation of Hearing in Noise. Noise Induced Hearing Loss by Lonsbury-Martin BL, Martin GK and Telischi FF, Volume 4, Chapter 126 in Otolaryngology-Head and Neck Surgery 3rd Edition. Permanent Impairment of Hearing - When any anatomic or functional abnormality produces a permanent reduced hearing sensitivity. Permanent Handicap for Hearing - The disadvantage imposed by an impairment sufficient to affect the individuala€™s efficiency in the activities of daily living (ADL). Permanent Disability - A person is permanently disabled or under permanent disability when the actual presumed ability to engage in gainful activity is reduced because of handicap and no appreciable improvement can be expected.
Acoustic Neuroma (Vestibular Schwannoma) - A benign brain tumour that arises on the vestibular nerve usually within the internal auditory canal (IAC). Menierea€™s Disease - A classic inner ear disorder associated fluctuant sensorineural hearing loss, tinnitus and episodic attacks of vertigo lasting minutes-hours.
Otitis Media with Effusion - An encompassing term that describes the presence of fluid behind the TM.
Otosclerosis- Genetically inherited condition (approximately 1 in 20 people carry the otosclerosis gene) associated with the development of new, immature bone which primarily involves the stapes footplate leading to a progressive conductive hearing loss.
Tympanosclerosis - Calcification of the middle layer of the eardrum that looks like a patch of white chalk.
Mastoidectomy - Procedure designed to exteriorize disease in the mastoid air cells and adjoining middle ear. Ossiculoplasty - Procedure where the ossicular chain is repaired in order to try and improve hearing. Tympanoplasty - When used in its most simplistic context it means the repair of a previous TM perforation. Ventilation (myringotomy) Tube - The placement of an open ended tube or a€?grommeta€? into the TM acts like an artificial Eustachian tube which helps ventilate the middle ear space.
Decibel (dB) - A decibel is an accepted measure of sound pressure level used to describe sound intensity. Evoked Response Audiometry - Measures electrical responses within the inner ear, cochlear nerve and central nervous system that are generated by loud repetitive clicks. This test is typically performed as one of the tests to confirm or exclude whether an exaggerated hearing loss (malingering) is present.
Otoacoustic Emissions (OAEs) - Evoked test that measures minute responses to sound thought to arise from the contractile elements of the outer hair cells.
Recruitment - Perceived abnormal progressive loudness of noise in an individual with a sensorineural hearing loss. Speech Discrimination Score (SDS) - The percentage score an individual correctly identifies when presented with a list of phonetically balanced (PB) words usually tested at 40dB above their hearing threshold.
Tympanometry - Formal tracing of how the TM moves when pressure is altered in the external auditory canal.
Acoustic Trauma - Damage to the ear caused by a single exposure to an impulse nose of high density. Continuous Noise - A noise that remains relatively constant in sound level for at least 0.2 seconds. Dosimeter - An instrument that integrates a function of constant varying sound pressure over a specified time period in such a manner that it directly indicates a noise dose and estimates the hazard of an entire exposure period. Permanent Threshold Shift (PTS) - The permanent depression in hearing sensitivity resulting from exposure to noise at damaging intensities and durations.
Temporary Threshold Shift (TTS) - The temporary (usually several hours) depression in hearing sensitivity resulting from exposure to noise at damaging intensities and durations. Time Weighted Average (TWA) - The sound level or noise equivalent that, if constant over an eight hour day would result in the same exposure as the noise level in question (assuming a 5 dB doubling rule).
The ear is a complex organ that has dual responsibility for hearing and balance (vestibular) function. The ear canal (external auditory canal) originates from the concha (so-called bowl) of the auricle and extends medially to the tympanic membrane. The ear canala€™s primary function is to provide a conduit for airborne sound waves to reach the tympanic membrane. The middle ear cleft is a more extensive designation of the middle ear that has three main components which include the middle ear cavity, mastoid air cell system and the Eustachian tube. The mastoid air cell system consists of a series of small mucosal lined air cells interconnected with each other and the middle ear proper.
Important structures of the middle ear include the tympanic membrane and the ossicular chain. The ossicular chain consists of the three small interconnected mobile bones known as the malleus (hammer), incus (anvil) and stapes (stirrup).
The inner ear is the sensory end organ within the hardest bone of the body known as the petrous portion of the temporal bone. The cochlea specifically refers to the sensory portion of the inner ear responsible for hearing.
The vestibular portion of the inner ear consists of three fluid lined semicircular (superior, lateral and posterior) canals and the area called the vestibule which houses the otolithic macular endorgans. Sound vibrations are picked up by the pinna and transmitted down the external auditory canal where they strike the TM causing it to vibrate. When the mechanical vibrations of the stapes footplate reach the inner ear they create traveling waves in the cochlea. Although the vast majority of the cochlear nerve fibres are termed afferent (ie nerves that carry electrical activity from the inner ear to the brain), within the cochlear nerve itself we have a small number of nerve fibres designated as efferent (nerves that carry electrical activity from the brain to the inner ear). Of interest when the outer hair cells become injured or affected by pathology they also lose their ability to a€?fine tunea€? the electrical responses arising from the inner ear. Although an individual may have apparently normal hearing it does not necessarily mean the cochlear nerve is undamaged. Sound is the propagation of pressure waves through a medium such as air and water for example. This is a very relevant question that is based on the definition of how hearing loss causes a handicap for the affected individual in their ability to identify spoken words or sentences under everyday conditions of normal living. Although the higher frequencies are initially affected in NIHL an individual will really only begin to demonstrate a significant handicap to hearing to everyday speech in a quiet surrounding when the average of the hearing thresholds at 500, 1000, 2000 ( + 3000) Hz is above 25 dB. The inclusion of the 3000 Hz threshold value for NIHL awards is not always required depending on the jurisdiction. In the province of Ontario the Workplace Safety and Insurance Board (WSIB)a€™s Operational Policy Manual (OPM) Document No.
A presbycusis (aging) correction factor of 0.5 dB is deducted from the measured hearing loss (averaged over the 500, 1000, 2000 and 3000 Hz frequencies) for every year the worker is over the age of 60 at the time of the audiogram.
It is important to also appreciate that decisions can also be made on an exceptional basis which the WSIB has recognized. Since individual susceptibility to noise varies, if the evidence of noise exposure does not meet the above exposure criteria, claims will be adjudicated on the real merits and justice of the case, having regard to the nature of the occupation, the extent of the exposure, and any other factors peculiar to the individual case. A comprehensive list of US comparisons for NIHL and benefits can be found in Table 35.1 pages 797-799 in the Chapter concerning State and Federal Formulae Differences in Occupational Hearing Loss, 3rd Edition.
It is likely that the two effects are not additive (Corsoa€™s theorem) but from a practical point of view this is how they are usually viewed with regards to compensation claims (Dobiea€™s theorem). At any given age for frequencies above 1000 Hz men will have more age related hearing loss than women. Age related hearing loss affects all frequencies although the higher frequencies are usually more affected. Age related hearing loss is an accelerating process where the rate of change increases with age. One can speculate that this might be one of the reasons an individual early on in their exposures may not be aware of a hearing loss, only to appreciate a hearing loss later in life when other factors such as presbycutic change occur. Although we think of presbycusis as an age related event not all individuals will develop this condition. Future genetic studies may provide us with further information concerning those at greater risk for progressive hearing loss from presbycusis in future. A TTS is considered to represent a pathological metabolically induced fatigue of the hair cells or other structures within the Organ of Corti. In a PTS the destruction and eventual cochlear hair cell loss is thought to arise from direct mechanical destruction from high-intensity sound and from metabolic decompensation with subsequent degeneration of sensory elements. While one would normally expect full recovery of hearing function after a TTS there is one important consideration that needs to be taken into account.
The position in the world literature continues to support that any progressive hearing loss from acute trauma ceases unless the individual is re-exposed to more acute acoustic trauma or some other factor (s) occurs ( i.e. The classic studies of acute acoustic trauma by Segal et al (1988) and Kellerhals (1991) are often used to support this position. In the cohort study by Segal et al, 841 individuals from either the regular US army or military reserve sustained a permanent sensorineural hearing loss from acute acoustic trauma without subsequent re-exposure. The importance of the Segal study is that after 1 year one would not expect further worsening of hearing in subjects who ceased to have further noise exposure.
Kellerhalsa€™ study reviewed a much smaller series of individuals who were exposed to acute acoustic trauma but looked at them over a 20 year duration.
We all know that loud sound can damage hearing yet all around us we see tweens, teens and young adults with headphones on and music loud enough to hear as a near bystander.
A study in 2010 using data from the National Health and Nutrition Examination Survey showed that one in five adolescents aged 12 to 19 has hearing loss. For the study, eleventh grade students from one high school answered the 10 hearing screening questions and additional questions assessing other potential risk factors for adolescent hearing loss.
The study found that neither the standard hearing screening questions nor the additional adolescent hearing loss risk questions were associated with adolescent hearing loss. School hearing tests currently used in most states screen mainly for low-frequency hearing loss, which is seen more often in younger children in association with frequent ear infections and fluid in the ear. The onset of high-frequency hearing loss is often very insidious and the symptoms are often very subtle,” Sekhar said. The study failed to find an association between typical adolescent noise exposures and hearing loss. Meinke & Dice (2007) evaluated a database of 641 9th and 12th graders with identified high frequency hearing loss using four different intensity and frequency combinations. For the last 17 years, I've traveled to over 40 countries, and every continent, as an audiologist conducting presentations and training on audiology and hearing instruments for a major manufacturer. Since diabetes is a systemic disease that affects multiple organ systems, it is reasonable to inquire if the auditory system is among those affected.  Although there has been evidence since the mid-19th century linking diabetes with hearing loss, controversy has surrounded this association.
Only the Epidemiology of Hearing Loss Study, a community-based investigation conducted in Beaver Dam, Wisconsin, detected a modest increase in occurrence of hearing impairment among adults with diabetes compared to those without diabetes. Conflicting evidence has prevented diabetes-related hearing impairment from receiving much attention among research scientists and much acceptance among health care professionals.  Recently, though, research findings suggest that impaired hearing is not only very common among older and middle-aged people with diabetes, but that hearing loss also affects young people with diabetes more than those with normal hearing.
A recent study by a Japanese team, Horikawa, et al (2013) found that, in general, diabetics were 2.15 times more likely to have hearing loss than people without the disease. 1.  Low HDL or high-density lipoprotein cholesterol, coronary heart disease, peripheral neuropathy, and having poor health are potentially preventable correlates of hearing impairment for people with diabetes. 2.  Some degree of hearing impairment affects over two-thirds of diabetic adults, about twofold higher than that of the non-diabetic population. 3.  Data that would have provided evidence that diabetes severity is associated with the likelihood of hearing impairment was inconclusive. Hearing impairment is not widely recognized as a complication of diabetes despite its occurrence in as many as two-thirds of our diabetic sample. While some of the diabetes related hearing impairment can be prevented, these data suggest that all diabetics should have their hearing screened to determine if their disease affects their hearing is compromised by the disorder.  As audiologists we need to encourage physicians worldwide to refer patients with diabetes for hearing evaluations to rule out a related hearing impairment. Key words: auditory domains, dizziness, hearing aid, nonveteran, pure tone thresholds, smoking, tinnitus, veteran, word recognition in competing message, word recognition in quiet. Abbreviations: ANOVA = analysis of variance, EHLS = Epidemiology of Hearing Loss Study, HFPTA = high-frequency pure tone average, HHIE-S = Hearing Handicap Inventory for the Elderly-Screening (version), HL = hearing level, LE = left ear, NU-6 = Northwestern University Auditory Test No. The population-based EHLS was an outgrowth of the Beaver Dam Eye Study of age-related eye disorders that enrolled 4,926 participants between 1988 and 1990 [8-9].
The primary purpose of this study was to determine the prevalence of hearing loss among male veterans and nonveterans aged 48 to 92 years who were enrolled in the EHLS. 1.Is there a higher prevalence of hearing loss for pure tones among veterans compared with nonveterans in the EHLS? 2.Is there a higher prevalence of hearing impairment for word recognition in quiet and in competing message among veterans compared with nonveterans in the EHLS? 3.What is the prevalence of self-assessed hearing handicap among veterans compared with nonveterans?
4.Are veterans more or less likely to use hearing health care services (have their hearing tested, try hearing aids, continue to use hearing aids, etc.) compared with nonveterans? The demographic data in Table 1 provide information about the 590 nonveterans and 999 veterans included in EHLS. Number and percentage of nonveteran male participants and veterans in four demographic categories. Table 2 provides the distributions for four general health categories and two ear-related categories for the two groups of participants. Number and percentage of nonveteran and veteran male participants in six health categories. Table 3 describes certain service-related characteristics of the 999 veterans involved in the study.
Number and percentage of male veterans in respective branches of armed services and years of military service. Pockets of tissue capable of regeneration may be sequestered in various portions of labyrinthine bone.
Recently, I've been trying to organize some of the columns and articles I've written over the past ten years. For audiologists, the audiogram is such a basic dimension and so self-evident that its explanation, after the thousandth time, is often unconsciously truncated and simplified. Yet in spite of the recent advances made in diagnostic audiological evaluations, and they are truly impressive, the information and insights provided by the simple audiogram can still provide the most pertinent information to explain the behavioral implications of a hearing loss. This is a figure of an audiogram (with frequency in Hz along the top and Hearing Loss in decibels down the left side). In addition to their energy locations on the frequency axis, speech sounds also vary in intensity. Looking at the audiogram again, and relating it to the speech banana, it is apparent that a person with this hearing loss will hear more of the lower frequency speech sounds than the higher ones. I don't want to give the impression that the perception of vowels is unimportant on the contrary, it is and can be very important -- only that by not actually hearing some of the consonants, hearing-impaired people have to struggle to fill in the acoustical gaps they produce in the stream of speech. This is a figure of an audiogram (with Frequency in Hz along the top and Hearing Loss in decibels down the left side).
What I have often found useful in explaining the need to understand the audiogram is commenting that it is possible for someone to be completely deaf and have completely normal hearing in the same ear at the same time. There is another dimension of hearing loss that is sometimes also included on an audiogram and that is the discomfort threshold. The dilemma of the threshold of discomfort for hearing-impaired people is that it is often the same as that observed with normally hearing individuals (perhaps 90 dB or so across frequency). Finally, it is important for people to be familiar with the details of their audiogram so that they can track any changes with time.
This hearing graph shows a typical loss of hearing in the 4,000 Hz range caused by noise damage.
Traditionally, hearing aids have been unable to provide sufficient amplification for sounds beyond 4,000 to 6,000 Hz. Recently, several manufacturers have introduced “extended bandwidth” hearing aids, which promote improved receivers that sufficiently amplify sounds to 8,000 Hz and beyond. Rather than attempting to extend the limits of the hearing aid's frequency response, some manufacturers have developed hearing aids with frequency-lowering technology. Non-linear frequency compression (NLFC) (Figure 2C) takes high-frequency information above a designated frequency range, referred to as the crossover frequency, and compresses it into a lower range as determined by a pre-set frequency compression ratio. Spectral envelope warping (SEW) (Figure 2D) is designed to capture a high-frequency sound information and replicate it at a lower frequency. All of the aforementioned frequency-lowering strategies possess potential advantages and limitations, and there are no published research studies showing one approach to be superior to another. Ask your audiologistAs previously mentioned, there can be disadvantages associated with frequency-lowering technology.
One of the most pressing difficulties of persons with hearing loss is an inability to effectively understand speech in the presence of noise. Directional microphone technology typically employs two or more microphones to amplify sounds coming in from the front as prescribed, while limiting or reducing amplification for sounds coming from the sides and back.
Although directional microphones may improve speech recognition in noise, it is probably prudent to refrain from their use until a child is old enough to consistently orient toward the signal of interest and provide verbal feedback about the potential perceived advantages and limitations of directional amplification.
Digital noise reduction (DNR) is another hearing aid noise technology designed to improve performance in noisy environments.
As with directional hearing aids, we are still examining the appropriateness of DNR for young children. However, it is important to remember that not all hearing aids work alike, and it is possible that some DNR algorithms may reduce gain for speech. Almost every major hearing aid manufacturer now has a way to wirelessly link your hearing aids with your personal technology (from phones to computers to TVs).


Personal remote microphone radio frequency (RF) systems have been around for a long time, and have long been recognized as the most effective means to improve speech recognition in noisy places. Perhaps it’s just icing on the cake, but besides all of the great technology that allows individuals to hear better in a variety of settings, several hearing aid companies have now made some of their products water-resistant. In summary, hearing aid technology has improved significantly over the past few years.  Although it is not perfect, contemporary technology can improve the communication abilities of most everyone with hearing difficulties.
In fact, there is limited knowledge about how children with hearing loss understand speech over the telephone. Recent reports have suggested that adults with significant bilateral hearing loss hear better on the telephone when listening with both ears compared to one. Unfortunately, wireless streaming devices are not always available for persons with hearing loss­—particularly for young children. A feature called DuoPhone from Phonak is an alternative solution designed to allow users to hear the telephone signal in both ears simultaneously without the need of an accessory.
There are no published studies examining the potential benefits of DuoPhone for pre-school children with hearing loss. 1) Bilateral hearing loss with a better ear four-frequency pure-tone average between 35 and 75 dB HL. 2) Symmetrical hearing loss with no more than a 20-dB difference in air-conduction thresholds between ears at 500, 1000, 2000, and 4000 Hz. 5) Expressive and receptive spoken language abilities within 1 year of their chronological age as indicated by standardized speech and language assessment conducted within the past year. The Audioscan RM500SL hearing aid analyzer was used to measure real-ear-to-coupler differences (RECD) for each child. The live speech mode of the Audioscan RM500SL analyzer was used to conduct simulated probe-microphone measure to assess the output of the hearing aid while a recorded speech passage was presented over the telephone. Next, the hearing aid manufacturer’s default “telecoil telephone program” was enabled with the hearing aid microphone attenuated by 10 dB rather than the software default 0 dB of attenuation for pediatric users. Once again, the live speech mode of the Audioscan RM500SL analyzer was used to conduct a probe microphone measure to assess the output of the hearing aid for a recorded speech passage presented over the telephone. Speech recognition over the telephone in quiet was measured for all 10 children, and speech recognition over the telephone in the presence of competing noise was measured for 8 of the 10 children (two of the children fatigued before testing could be completed in noise). Separate repeated-measures analysis of variance (RANOVA) was used to analyze the results obtained in quiet and in noise because two children were unable to complete the noise condition. 1) Pre-school children achieve substantially better speech recognition on the telephone in quiet and in noise when using the DuoPhone compared to their performance in the monaural condition. 2) Simulated probe-microphone measures were used to ensure that the output of the telephone program was appropriate. It is intended to provide a broad and general overview of a medical topic that is frequently considered in Tribunal appeals. Each author is asked to present a balanced view of the current medical knowledge on the topic. A vice-chair or panel may consider and rely on the medical information provided in the discussion paper, but the Tribunal is not bound by an opinion expressed in a discussion paper in any particular case. This is the type of hearing loss that is found in routine unprotected daily exposure to loud noise potentially injurious to hearing in the occupational work force. This type of loss might be found in an individual, for example, with a large tympanic membrane (TM) perforation where mechanical vibrations along the ossicular chain are dampened. For example an individual with a large TM perforation who received topical antibiotic ear drops for the treatment of a middle ear infection that caused inadvertent toxicity to the inner ear in addition (i.e. The hearing loss may range from mild to profound, may result in tinnitus (unwanted head noise) and is cumulative over a lifetimea€?.
Noise induced deafness generally affects hearing between 3000-6000 Hz with maximal injury centering around 4000 Hz initially, an important point to remember. There is good pathologic evidence however that demonstrates maximal cochlear hair cell loss in the tonal areas where the 4000 Hz hair cells normally reside in both animals and humans. In susceptible individuals the early effects of presbycusis are occasionally seen around age 40.
Secondary to hair cell loss one can often see progressive neuronal dropout along the cochlear nerve. In this regard the effects of aging in the absence of other factors cause a loss of hearing at all frequencies whose rate of growth becomes more rapid as age increased (especially after 60 years): an important point to remember in this context. To a large degree hearing loss with age is genetically primed; in other words the hearing your parents had as they aged is often passed on to you.
When the two processes are combined the resultant pathology and its effects upon hearing are not as well understood. This certainly generates a more complicated mathematical model but probably more closely approaches what is happening physiologically. The hearing loss is typically a low-frequency sensorineural loss that fluctuates initially often reverting close to normal between attacks in the early stages.
The presence of a pink-flamingo hue to the middle ear on otoscopy (so-called Schwartzea€™s sign), absent stapedial reflexes on audiometry and bone density changes involving the surrounding bone of the inner ear best appreciated on high-resolution CT scanning also helps in the diagnosis. Most patients suffering deafness by this mechanism will have had at least transient unconsciousness and have been admitted to hospital.
A fracture through this bone (which is the hardest bone in the body) implies the force of the injury was severe and often incompatible with survival. Unfortunately these antibiotics can cause varying degrees of cochlear, vestibular and renal toxicity.
The Auditory Brainstem Response (ABR) is used as a screening test while a gadolinium enhanced Magnetic Resonance Imaging (MRI) study is the gold standard investigation. The extent of the loss varies from a partial loss at one frequency right up to a profound loss at all frequencies with a profound discrimination loss. For the purposes of compensation, the most reliable audiograms will likely be performed by an audiologist who typically has a mastersa€™ degree or doctorate in audiology. The audiometer used to test hearing has been especially calibrated so that each frequency of sound tested for hearing has been normalized where 0 dB represents the lowest intensity of sound that the majority of people with normal hearing can hear from large population studies. When a conductive hearing loss is suspected the ear canal and inner ear mechanisms for transmission of sound energy to the inner ear are bypassed by placing a bone vibrator over the mastoid which directly stimulates the inner ear. A weighted pure tone average from frequencies at 500, 1000, 2000 and 3000 Hz is required for this determination from AC thresholds if a pure sensorineural hearing loss is present or from BC thresholds if any conductive element to hearing loss is present.
As a general rule the SRT value should roughly equal the pure tone average in the speech frequencies at 500, 1000 and 2000 Hz.
Most individuals with normal sensorineural hearing should get over 80% of the words correct at this level. Most individuals with normal sensorineural hearing will exhibit a reflex at 70-80 dB above their hearing threshold level at the frequency being tested. When reflexes occur at less than a difference than 70-80 dB above hearing threshold at the frequency tested this is indirect evidence of a phenomenon called recruitment which is usually seen in cochlear pathology (i.e.
ECoGa€™s chief value lies in its ability to demonstrate wave 1 of the auditory brainstem response (ABR) and whether waveform morphology is suggestive of changes thought to occur in endolymphatic hydrops, the pathophysiologic substrate of MeniA?rea€™s disease.
This test measures electrical waveforms obtained in the first 10 msec from cochlear stimulation. Middle ear pressures should be normal, stapedial reflexes present and a normal tympanogram noted. In some instances it can be quite disabling for the affected individual who tends to withdraw from any exposure to uncomfortable noise.
Cognitive behavioural therapy (CBT) has also demonstrated promise in a recent randomized controlled study.
The Relative Contributions of Occupational Noise and Aging in Individual Cases of Hearing Loss.
Specialized treatment based on cognitive behavior therapy versus usual care for tinnitus: a randomized controlled trial. Diabetes and hearing impairment in the United States: Audiometric evidence from the National Health and Nutrition Examination Survey (1999-2004). The pathology is thought to arise from excess fluid in the inner ear leading to membrane ruptures (so-called endolymphatic hydrops). Certain antibiotics (especially the aminoglycoside class), antimalarials, chemotherapeutic agents and even excessive doses of ASA can be toxic to the inner ear. Although changes may take place as early as age 40, hearing loss due to aging usually starts to accelerate around ages 55-60 yrs and continues with age.
Auditory Brainstem Response (ABR) - Synonymous with the term BERA (brainstem evoked response audiometry) or auditory BEPa€™s (brainstem evoked potentials). Cortical Evoked Response Audiometry - Synonymous with Threshold Evoked Potential (TEP) testing. Depending on the frequency of the sound certain parts of the cochlea will emit an a€?echoa€? in response.
This occurs to a loud noise typically 70-80 dB above an individuala€™s hearing level at the frequency tested which causes stiffness of the ossicular chain and tympanic membrane Absent stapedial reflexes are usually seen in otosclerosis due to stapes footplate fixation for example.
Conceptually it has three distinct anatomical components which include the external, middle and inner ear. The auricle is a flattened, funnel shaped appendage that contains a cartilage framework covered by skin.
The anatomy favours the transmission of sound waves typically between 500-8,000 Hz which interestingly represents the common speech frequencies of most individuals. Proper function of the Eustachian tube which connects the middle ear cavity to the back of the nose (nasopharynx) is important for the normal middle ear aeration and function. The tympanic membrane or ear drum is an ovoid, pale gray, semi-transparent membrane positioned obliquely at the medial end of the ear canal.
The tensor tympani and stapes muscles help stabilize the bones along with suspensory ligaments of connective tissue inside the middle ear. Covered by an otic capsule its membranous portion (or labyrinth) contains a delicate system of fluid-filled canals lined with sensory neuroepithelium necessary for hearing and balance perception.
It is a three chambered organ containing anatomical spaces known as the scala media, scala vestibuli and scala tympani. The scala vestibuli and scala tympani (T) by comparison contain fluid rich in sodium called perilymph. Within each semicircular canal is an area called the ampulla which contains hair cells sensitive to low frequency bidirectional fluid displacement that occurs with angular acceleration type movements of the head.
The sound vibrations are then transmitted across the air-filled middle ear space by the 3 tiny linked bones of the ossciular chain: the malleus, incus and stapes . The hair cells change these mechanical vibrations from the waves into electrochemical impulses that can interpreted by the central nervous system (CNS). It can be a simple sound commonly known as a pure tone or it may be complex when we think of speech, music and noise. The prediction of a handicap did not appear to be improved by the inclusion of other frequencies > 4000 Hz.
What do other jurisdictions consider to be disabling hearing loss (provincial, national and international)? The hearing loss that remains after the presbycusis adjustment is then used to determine entitlement to benefits.
It is generally thought that if an ear has suffered a permanent threshold shift from a noise induce etiology further noise exposure will cause less damage than would occur in a normal ear to a similar exposure.
As previously noted the effects of noise exposure and aging on hearing when not combined are reasonably well understood. One however has to qualify this by saying that there is a significant amount of redundancy within the inner ear as it pertains to hearing. Moreover we really dona€™t have a lot of good prospective longterm studies over 4-5 decades that can ultimately answer this question completely. Can moderate workplace noise exposure causing a TTS and repeated exposures later cause a PTS? Repeated noise exposure that causes a temporal threshold shift (TTS) can ultimately lead to a permanent threshold shift (PTS) with repeated exposures. Some of this is based on the redundancy principle within the inner ear: not all hairs cells possibly recover following a TTS but enough do as to prevent hearing loss. Following acute acoustic trauma what is the natural history of the subsequent hearing loss? Audiometric evaluations were performed on these individuals at 6 months, 1, 2 and 4 years after initial exposure. In his study cohort only 1% of individuals following acute acoustic trauma demonstrated deterioration of hearing of more than 20 dB in at least 1 frequency. Most have high-frequency hearing loss, which may be related to increasing hazardous noise exposures from such things as personal listening devices, concert-going, ATV-riding and hunting with firearms. In addition, the school hearing test was found to have a sensitivity of only 13 percent for adolescent hearing loss while the study-designed hearing test had 100 percent sensitivity. The challenge in doing so may stem from the fact that genetics and duration of exposure are additional factors that affect an individual’s risk of hearing loss. I've learned that audiologists the world over, while a diverse group, share the same goals and objectives for our patients. Also, the risk of a stroke or fatal cardiac event is two to four times higher among adults with diabetes than those without diabetes.
Early attempts to establish an association between diabetes and hearing impairment were not very convincing, probably due to subject selection, design or other errors. The total number of people with diabetes is projected to rise from 171 million in 2000 to 366 million in 2030. This article reports the results of several auditory measures from 999 veteran and 590 nonveteran males 48 to 92 years of age included in the EHLS.
6, PTA = pure tone average, RE = right ear, SD = standard deviation, SNR = signal-to-noise ratio, VA = Department of Veterans Affairs. Studies indicate the prevalence of hearing loss in the elderly population (>65 years) ranges from 27 to 45 percent and increases with age [1-6]. Of the 4,541 available participants at the 5-year follow-up visit of the Eye Study, 3,753 individuals (82.6%) agreed to participate in the EHLS between March 1993 and July 1995 [7].
The percentage of nonveterans and veterans in each of the four age groups varied, which is reflected in the significant χ2. Handedness was the same for both groups of participants with 89 percent responding right handed, 7 percent responding left handed, and 4 percent responding ambidextrous (data not shown in Table 2).
These tissue could be activated by the presence of regenerative enzymes in the blood following bone fracture elsewhere in the body.
As I was looking through them, it became apparent that I've neglected to discuss what is perhaps most important hearing dimension of all, the simple audiogram.
Perhaps the most important insight of all is an appreciation of how specific audiograms impact upon the perception of certain speech sounds.
Frequency (or pitch) is depicted on the horizontal axis, from low frequencies on the left (250 Hz) to high frequencies on the right (8000 Hz). This is a general, but static, representation of the acoustical speech energy across frequency. In reality, however, conversational speech is a dynamic and time-varying event, with one speech sound (phoneme) following another in a rapid succession.
Those individuals with superior linguistic skills would perform this task better than those with lesser skills.
Somebody with this type of hearing loss actually hears better at 250 Hz than the one whose audiogram is shown in figure 1, but much worse at 1000 Hz and higher.
Without a hearing aid (and even with one) this person needs to depend upon visual cues (speechreading) to supplement the information received through hearing. Looking at this audiogram, we can state that this person has perfectly normal hearing in the left ear, but this is only true at 250 Hz and 500 Hz.
In a room full of people with hearing loss, it is doubtful that any two would exhibit exactly the same audiogram for both their ears.
While an audiogram can help explain much of the auditory behavior of a person, it does not explain it all. But because their threshold of hearing is elevated, but not their threshold of discomfort, this means that people with hearing loss generally have a reduced listening area (or narrow dynamic range). This typically occurs in individuals who are exposed to gunfire, firecrackers, or a rock concert.
The first one shows the peak noise levels, in decibels or dBs (that is the measure for how loud sound is) for various events. Today, some advanced technology features, which were formerly only available in expensive, high-end hearing aids, are now available in economy-level hearing aids.
The ability to hear high-frequency speech sounds is crucial for understanding speech as well as the rules underlying language and grammar, such as plurality, possessives and subject-verb agreement. The speech sounds on the audiogram are placed in the pitch and intensity range at which the sounds are typically heard. This constraint was primarily attributed to a limitation of the hearing aid receiver (the term used to refer to the miniature speaker of the hearing aid), which simply could not provide adequate amplification of high-frequency sounds. Although this technology is promising, there is a paucity of studies showing significant improvements in speech recognition with the use of extended bandwidth amplification.
Frequency lowering can be achieved by linear frequency transposition (LFT), non-linear frequency compression (NLFC), or spectral envelope warping (SEW). Similar to LFT, the bandwidth of the high-frequency sound information is not altered, SEW moves the high-frequency of sound to a lower frequency range, where the low-frequency and high-frequency sounds are overlaid on one another.
In particular, if the frequency-lowering is too aggressive, then speech and environmental sounds may become distorted resulting in poor sound quality and a reduction in speech understanding. Studies have shown that around 40% of adult wearers continue to be unsatisfied with their ability to hear in noise after being fitted with hearing aids (Kochkin, 2010).
This approach assumes that the wearer will face the signal of interest in a noisy environment, and consequently, the speech will be enhanced and the surrounding noise will be reduced.
In fact, some hearing aids even go a step further and remain in omni-directional mode if the primary signal arriving from behind the user is speech.
Hopefully, ongoing research and development will clarify the question of whether young children should use adaptive directional amplification and possibly even result in a hearing aid that limits the potential disadvantages of directional amplification for children.
DNR analyzes the sound arriving to the hearing aid, determines whether it is speech or noise, and reduces the aided gain when background noise is the dominant input. It is imperative that the audiologist verify that gain is not reduced when speech is present. In people with typical hearing, the ears work together to better understand speech in noisy environments as well as to determine the direction from which a sound originates.
Directionality with Binaural Processing.Furthermore, some hearing aids work together so that a wearer may adjust the volume or a program on one hearing aid and the change automatically happens at the other hearing aid. Some companies use “streamers” (a device you wear around your neck to allow you to interface between the hearing aids and the accessory) to wirelessly connect to your personal products, while other manufacturers have developed hearing aids that allow you to wirelessly connect without an interface device. Recently, manufacturers have started introducing digitally-modulated RF systems, which are similar to Bluetooth® technology used in several recreational and business applications. Some even claim you can swim with them.  It is important to consider how the warranty works if you do choose to participate in water activities with the hearing aids on. If you are struggling with your hearing, you should consult your audiologist to determine whether new technology may alleviate your communication difficulties. In particular, there have been no reported studies that have evaluated whether children with hearing loss may understand speech over the telephone better while listening with two ears compared to one. Picou and Ricketts3,4 recently reported on two studies in which they examined recognition of recorded speech presented over the telephone for a group of adult hearing aid users. These devices typically require an additional investment in technology, and these accessories may not be readily available every time a child chooses or needs to talk on the telephone. DuoPhone uses digital, near-field magnetic induction to wirelessly stream audio signals from one hearing aid to the hearing aid on the opposite ear.
As a result, the primary objective of this study was to compare speech recognition in quiet and in noise for a group of pre-school children (ages 2-5 years old) with hearing loss when listening with binaural (DuoPhone) versus monaural telephone input.
All subjects were fitted with Phonak Bolero Q90-M13 behind-the-ear (BTE) hearing aids, except for one subject who had a four-frequency pure-tone average of 81 dB HL in the poorer ear and was fitted with Phonak Bolero Q90-SP BTE hearing aids.
Simulated real ear output for standard conversational level speech presented from the Audioscan Verifit loudspeaker (Green), for a recorded speech passage presented to the microphone of the hearing aid (Pink) (ie, “Acoustic Telephone”), and for a recorded speech passage presented to the hearing aid telecoil (Blue). During the procedure, one of the study examiners held the receiver of the telephone handset next to the microphone of the hearing aid.
As before, one of the study examiners held the receiver of the telephone handset next to the body of the hearing aid. Speech recognition was assessed in all conditions with a half-list (25 words) of Northwestern University-Children’s Perception of Speech test (NU-CHIPS) open-set words7 presented by the same female talker throughout the study. Mean NU-CHIP word recognition scores (with 1 SD bar) in quiet and in the presence of noise for the monaural and DuoPhone conditions. Mean word recognition scores in the monaural and binaural phone conditions are provided in Figure 3. Similar measures should be considered for clinical purposes to ensure that the telephone signal is audible for young children. Audiologists should devote time to counseling the families of pre-school children regarding strategies for optimal telephone use. Binaural hearing on the telephone for pre-school children with hearing loss. Hearing Review.
Occupational NIHL and presbycusis (degenerative hearing from aging change) represent the two most common causes of sensorineural hearing loss in society today.
For this reason workers ideally should be out of noise for at least 24 hours if not 48 hours prior to audiometric testing to avoid the effects of TTS on hearing.
Noise exposure from chipping machines and jackhammers characteristically damage the higher frequencies severely before affecting the lower frequencies.
Nevertheless some individuals exposed to noise not infrequently demonstrate some asymmetry to their hearing loss.
The majority of changes histopathologically are noted in the basal turn of the cochlea where the high frequency hair cells and their corresponding cochlear nerve neurons are found. When the distended membranes rupture the resulting admixture of inner (endolymph) and outer (perilymph) fluids causes electrolyte disturbances (i.e.
When the foci primarily affect the cochlea the patient may present with a chronic progressive sensorineural hearing loss in one or both ears.
As otosclerosis is a lifelong condition, the sensorineural hearing loss from cochlear otosclerosis is often superimposed on hearing loss from advancing age (i.e. The hearing loss noted is usually conductive and usually arises from discontinuity of the ossicular chain although any combination of conductive and sensorineural hearing loss can occur.
If the individual survives there is usually complete loss of hearing and vestibular function on the involved side.
Persistence of a conductive loss after the TM has healed would suggest continued problems with the ossicular chain.
Careful and regular monitoring of auditory function (especially in the ultra high frequencies > 8000 Hz) and serum antibiotic levels may help the physician predict when ototoxic effects are occurring.
Pressure on or devascularization of the acoustic nerve or inner ear causes hearing loss, usually a high-frequency loss with reduced speech discrimination. Patients can sometimes identify the moment of occurrence or wake with it or appreciate it only when they go to use the phone. If there is a significant discrepancy this could imply an exaggerated hearing loss is present as well. When speech discrimination scores are especially poor this implies that there may be a lesion involving the cochlear nerve (i.e.
In general terms if the Eustachian tube is functioning normally pressure on both sides of the ear drum should be similar (i.e.
Waveform morphology is thought to arise from the cochlear nerve and the various relay stations in the brainstem the electrical response has to travel through. The test is often indicated in an individual if there are concerns regarding an exaggerated hearing loss.
Tinnitus maskers are noise generators worn like a hearing aid that produces a sound of similar frequency to an individuala€™s tinnitus. The problem with tinnitus however is that it is difficult to quantify objectivity and to fully appreciate how it affects an individuala€™s well-being. This test measure electrical activity along the cochlear nerve and at the various relay stations in the brainstem between 1-10 msec of stimulation.
This test looks at electrical waveforms in the cortical areas of the brain between 50-200 msec after cochlear stimulation. In humans the auricle has rudimentary functions for gathering sounds and in sound localization which is much more important in animals.
The first part of the ear canal is cartilaginous and is lined by thick, hair bearing skin that contains numerous sebaceous and ceruminous glands.
Malfunction of the Eustachian tube remains the leading cause for most middle ear disorders. The air cell system is typically underdeveloped or even absent (sclerotic) in individuals with a past history of recurrent ear disease.
It is a three layered structure whose outer epithelial layer is contiguous with the skin of the external auditory canal, its middle layer is fibrous and its inner layer is composed of the same mucosal lining found throughout the middle ear cleft. Clinically the malleus is attached by its handle to the tympanic membrane and is readily visible in most individuals on otoscopic examination. The separate but intimately related perilymphatic and endolymphatic compartments of the inner ear and their ionic constituents are efficiently controlled by the stria vascularis of the cochlea and the dark cells of the vestibular apparatus.
This ionic difference between these chambers forms the basis of the endocochlear electrical potential which is necessary for the conversion of mechanical activity from fluid movement within the cochlea to electrical activity arising from the hair cells. The hair cells of the otolithic endorgans (utricle and saccule) are covered by otoliths ( literally a€?little stonesa€? or crystals of calcium carbonate ). The mechanical vibrations are transmitted to the inner ear via the vibrations of the stapes footplate. The tiny cilia (little hairs) on top of the hair cells (both inner and outer) are covered by a gelatinous membrane called the tectorial membrane.
This apparent internal a€?feedback loopa€? is thought to be responsible for a€?fine tuninga€? by inhibiting some unwanted electrical impulses and by changing the mechanical properties of the basilar and tectorial membranes.
Distortion of certain sounds arises when enough hair cells are damaged such that the hearing threshold is reduced. A cycle of a pure tone is represented by a sine wave appearance with an area of compression followed by rarefaction. Low sounds tend to have a long wavelength relative to higher pitched sounds which have shorter wavelengths by comparison.
Entitlement to health care and rehabilitation benefits is available when the adjusted hearing loss is at least 22.5 dB in each ear. When the two processes are combined, the resultant pathology and its effects upon aging are not as well understood. In other words many hair cells in a similar region of the cochlea will produce a certain frequency response to sound stimulation. Upon saying this however we can actually demonstrate that many individuals will start to show early changes in hearing as early as age 40 years (in subjects screened to rule out other ear disease and noise exposure). It is agreed that hearing loss and injury to the ear increases with the noise level, the duration of exposure, the number of exposures and the susceptibility of the individual. The findings also indicate that the late progression of hearing loss following a single episode of acute acoustic trauma did not exist.
Researchers are working to develop an objective hearing screening test custom-designed for adolescents with more high-frequency tones above 3,000 Hertz. I invite guest articles on topics ranging from differences in training, expertise, and scope of practice from one country to another to interesting, debonair, or disgusting practices.
Altogether, the data covered 7,377 diabetics and 12,817 people without the condition.  Some scientists, however, caution that this kind of study does not prove that diabetes is directly responsible for the greater rate of hearing loss among those with the disease.
Figure C suggests the difference in hearing for those with peripheral neuropathy, with the peripheral neuropathy patients having the worse of the two audiograms presented.  Finally Figure D presents the healthiness of the patients, with those in poor health having worse hearing. The prevalence of diabetes is higher in men than women, but there are more women with diabetes than men since men do not live as long.
The auditory measures included pure tone thresholds, tympanometry and acoustic reflexes, word recognition in quiet and in competing message, and the Hearing Handicap Inventory for the Elderly-Screening (HHIE-S) version. The results from one population-based study focusing on the prevalence of hearing loss, the Epidemiology of Hearing Loss Study (EHLS) conducted in Beaver Dam, Wisconsin [7], indicated that 46 percent of older adults were affected by hearing loss.


We examined self-assessed hearing handicap using the Hearing Handicap Inventory for the Elderly-Screening (HHIE-S) version [12]. The encouraging statistic is that current smoking is down to about 15 percent in both groups, which demonstrates a substantial decrease in smoking for both groups of participants. For people who may not even have heard of a pure-tone audiometer before they stepped into the audiologist's office, this is a quite understandable. Without including speech in the equation, it is simply not possible to intelligibly discuss the audiogram. For some specific purposes, it may be useful to test 125 Hz as well as some frequencies higher than 8000 Hz (for example, a progressive hearing loss above 8000 Hz can occur with certain type of ototoxic medications). Some speech sounds, such as vowels are predominately composed of low frequency energy, with less of their power in the higher frequencies. The specific acoustical composition of speech sounds is partially shaped by the preceding and following sounds in an utterance. Looking at the speech banana, it is apparent that while a great deal of low frequency vowel energy will be perceived, practically no high frequency consonants would be.
Some people, because of their superior ability to utilize some of the secondary cues in a speech signal referred to above, or their superior linguistic ability may do better than these comments would suggest. Or one could assert that he is completely deaf in the left ear, as again indeed he is (but only at 4000 Hz and higher).
There would be differences in degree of hearing loss at the different frequencies as well as divergences between the ears.
We know that there are other dimensions to auditory experiences that cannot be explained by the audiogram. The second shows the stands set by the Occupational Safety and Health Administration (OSHA) for the amount of noise you can be exposed to at work. Most of the time the damaging frequencies created by instruments are the high-frequencies.
So, is there anything you can do besides not playing your instrument and not listening to your music?
For a musician, rapid hearing loss is always a disaster and a good reason without any hesitation to consult an ear specialist. Age-related hearing loss is highly hereditary, and its progress can vary significantly between individuals.
After age-related hearing loss, noise-induced loss of hearing is the second most common cause of hearing loss among the adult population.
This article discusses several new hearing aid technologies and suggests questions that you may want to ask your hearing health providers when you select your next set of hearing aids. Furthermore, research has shown that when children with hearing loss cannot adequately hear sounds above 4,000 Hz, they will have to be exposed to three times as many words as children with typical hearing to learn new vocabulary and concepts due to the reduced acoustic bandwidth caused by the hearing loss (Pittman, 2008). Audiologists should properly select good candidates for frequency-lowering technologies, program this technology appropriately for the individual’s needs, and verify the benefit the wearer receives through the use of probe microphone measures (ask your audiologist about probe microphone measures if you are unaware of this important hearing aid assessment tool).
Numerous research studies have shown that directional microphones improve speech understanding in noise more than any other technology currently built into hearing aids (although directional microphones do not provide as much improvement in speech understanding in noise as remote microphone radio frequency systems—also commonly known as FM systems—which are an assistive technology that may be used with hearing aids to provide the most improvement in speech recognition in noise (Schafer & Thibodeau, 2004)).
With this approach, the risk of missing out on important speech signals arriving from behind or from the side of a hearing aid wearer is limited. Bentler and colleagues (2010) did show that DNR may improve listening comfort for children in noisy situations. For instance, we can tell that a sound originates from our right side, because it is a little louder and arrives a little earlier at the right ear than the left. Some hearing aids also have the capability of allowing the user to hear the sound from a telephone in both ears simultaneously when the phone is placed next to one of the hearing aids.
Here, a directional hearing aid provides amplification for sounds arriving from directly in front of the wearer, while reducing the volume for sounds arriving from other directions. Here, a listener is using hearing aids with directional microphones enhanced by binaural processing. Some manufacturers also offer a wireless microphone accessory, which can pick up an important voice and wirelessly send it to the hearing aids directly or via the streamer.
Because the microphone is positioned closely to the mouth of a parent or teacher, the speech signal captured by the system’s microphone is typically much higher in volume level than the surrounding background noise. Digital RF systems are able to provide a higher level of analysis and control over the signal that is captured by the microphone and eventually delivered to the receiver. Some are not “water-resistant” per se, but have a special coating inside the electronics that helps repel moisture—especially good if you (or your child) are susceptible to excessive sweating or have wax problems. Specifically, the investigators showed that 16 of 18 adults with moderate-to-severe sensorineural hearing loss achieved less than 50% correct speech recognition over the telephone when assessed in the unilateral condition (ie, the telephone receiver held next to the microphone of one hearing aid).
Furthermore, wireless streaming accessories are not usually configured to easily interface with most landline telephones but instead are designed to work primarily with mobile devices. The user simply holds any landline or mobile telephone next to the hearing aid, and the signal that is captured by the hearing aid microphone or telecoil is wirelessly transmitted from one hearing instrument to the other.
Digital noise reduction and directional microphone features were disabled for the fitting and for the speech recognition assessment conducted in this study.
Then, the hearing aid was set to the manufacturer’s default “acoustic telephone program” (ie, a telephone program intended for placement of the telephone receiver next to the microphone of the hearing aid-no telecoil). Adjustments were made to the hearing aid gain to ensure that the output of the hearing aid was at least as high as what was obtained to the 60 dB SPL Standard Speech signal (Figure 2). Adjustments were made to the hearing aid gain to ensure that the output of the hearing aid matched (±3 dB) what was obtained for the measurement made with the acoustic telephone program (Figure 2). This improvement is similar to the improvement Picou and Ricketts3,4 reported when comparing binaural telephone performance of adults to monaural use.
Studies on bilateral cochlear implants at the University of Wisconsin’s Binaural Hearing and Speech Laboratory. Efficacy of hearing-aid based telephone strategies for listeners with moderate-to-severe hearing loss. Remote Microphone Hearing Assistance Technologies for Children and Youth from Birth to 21 Years. Speech recognition in noise in children with cochlear implants while listening in bilateral, bimodal, and FM system arrangements.
Tribunal adjudicators recognize that It is always open to the parties to an appeal to rely on or to distinguish a medical discussion paper, and to challenge it with alternative evidence: see Kamara v.
Constant or steady state noise by comparison remains relatively constant and lasts longer although fluctuations in sound intensity may occur.
This is however usually related to the fact that one ear receives a greater exposure to the noise than another. Nevertheless the changes seen in presbycusis are typically non-specific and can also be seen in a vast number of pathologies including the effects of noise upon the inner ear.
Occasionally both a low-frequency and a high-frequency loss occurs but not usually the type of high frequency loss seen following noise exposure.
When vertigo is incapacitating the balance function of the inner ear may be attenuated or ablated by the trans-tympanic instillation of gentamicin with relative preservation of hearing.
If the footplate as well as the cochlea is involved then a mixed (conductive and sensorineural) loss might result.
The pathognomic sign of a longitudinal temporal bone fracture is the so-called a€?step deformitya€? in the deep ear canal.
Facial paralysis from an injury to the facial nerve (a nerve that runs in close approximation to the inner ear) typically occurs. The prolonged use of topical aminoglycoside antibiotics to treat middle ear pathology in the presence of a TM perforation is not without some risk which should always be kept in mind. In fact some people with a€?superhumana€? hearing can even hear sound intensities less than this relative value of sound pressure. In complex situations (mixed hearing losses) it may also be necessary to a€?maska€? the ear not being tested (to prevent crossover of sound to the other ear).
When tinnitus is severe enough to affect an individuala€™s well-being a trial of pharmacological treatment is generally recommended. Investigations such as a magnetic resonance imaging (MRI) are generally required to exclude the remote possibility of central nervous system pathology. Because of the brains proximity possible life-threatening complications can occur if left untreated (i.e. This test is typically performed when an asymmetric sensorineural hearing loss is present when there is concern a retrocochlear lesion such as an acoustic neuroma or MS might be present. The presence of waveforms following stimulation with the lowest intensity sound an individuala€™s cochlea hears provides us with a reasonable estimation of an individuala€™s hearing (usually within 5-10 dB of the anticipated threshold hearing at the frequency tested). The deeper part of the ear canal is bony, lacks skin appendages and is lined by thinner skin densely adherent to the periosteal lining of the bone. It is anatomically divided into 2 parts: the pars tensa and the pars flaccida (located in what is called the attic region of the tympanic membrane).
Medially the arch (crura) of the stapes attaches to the inner ear via its footplate (which is a thin, flat oval piece of bone approximately 7mm X 3mm in dimension). Series of generation potentials culminate to form action potentials that transmit this electrical activity along the cochlear nerve fibres to the brainstem and onto the higher centers of auditory processing.
The hair cells of the vestibular macula respond primarily to gravity and linear accelerations.
The presence of active non-muscular contractile elements within the outer hair cells and their effects on movement of the basilar membrane is used to explain the concept of otoacoustic emission (OAE) testing.
When the sound gets loud enough the inability to a€?fine tunea€? sound becomes lost and more nearby hair cells are drawn into the firing needed to create an electrical signal; hence the distortion of a loud sound.
Hair cell loss can continue until a certain critical point is breeched with the individual unaware of a hearing deficit.
Follow-up beyond the 1 year mark did not reveal any further deterioration of hearing in any individual.
Stories of travel, clinical practice, research, training diversity and other topics are of particular interest. It found a higher threshold among diabetic persons only at 500 Hz (Ma, Gomez-Marin, Lee, & Balkany, 1998). Diabetic subjects with low HDL, a history of coronary heart disease, symptoms of peripheral neuropathy, or those who report poor health also exhibited a greater likelihood of hearing impairment.
Hearing loss in the auditory domains of pure tone thresholds, word recognition in quiet, and word recognition in competing message increased with age but were not significantly different for the veterans and nonveterans.
The prevalence of hearing loss increased with age and was more common in men than in women. Because the EHLS queried the participants about their status as a veteran from one of the U.S. Except for 132 homebound residents who were tested in their homes, all other auditory testing was completed in a sound booth. The nonveteran and veteran groups also were significantly different in the education category.
The two groups of participants did not differ in the three remaining general health categories in Table 2, diabetes, history of myocardial infarction, and history of head injury. Even though just about everybody who receives a hearing aid has his or her hearing tested with a pure-tone audiometer, not everybody receives a comprehensive explanation of exactly what the results mean and what the implications are for them. To expect them to fully understand how the pattern of their hearing loss impacts upon their listening behavior is not very realistic. This, after all, is the signal we are most interested in hearing (not to minimize the specific needs of certain groups of people for other types of sounds, such as musicians). The amount of hearing loss is shown on the vertical axis with the higher numbers indicating a greater degree of hearing loss. The intensity of all other speech sounds in the English language fall within these bounds (note, however, that this does not take into consideration inflected speech, which will move the entire speech banana up and down). These specific effects, such as the unique modifications in vowels made by different preceding and following consonants, are actually secondary cues that can be helpful for understanding speech. Yes, but only with some difficulty and then only if the talker is close by and raises his or her voice slightly. Looking at the audiogram, we can understand somewhat why this should occur: they are not hearing the full range of high frequencies where many of the consonants have their predominant energy. An individual with this audiogram would have even more difficulty in understanding speech than the one whose audiogram is shown in figure 1.
But there are limits to even the keenest brain and the most developed auditory integration ability; at some point, people do need to detect speech energy in order to understand a spoken message. While there is merit and often necessity to this practice, there is also the danger of oversimplification.
In the right ear, the hearing loss at each of the three frequencies is the same, also resulting in an average of 40 dB.
People with bilaterally symmetrical hearing losses (that is, with similar hearing losses in both ears) may have quite different auditory experiences than people with bilaterally asymmetrical hearing losses. Still, the audiogram is a good place to begin when trying to understand someone's speech perception problems. Sounds delivered by the hearing aid below the threshold of hearing would not be audible; those exceeding the threshold of discomfort would not be tolerated (the hearing aid user would either turn the volume control down or simply remove the hearing aid). It is a good idea for people to keep copies of all the audiometric tests administered to them so that comparisons can be made (and to be sure that they are dated correctly). The unfortunate thing about the loud noises that are around us is the fact that they cause hearing loss just in the range that is important for speech. At retirement age, approximately every third person has suffered some degree of hearing loss, mostly as the result of ageing. Permanent noise damage can be caused by long term exposure to noise or by very loud one-off noise. The “Familiar Sounds Audiogram” shown in Figure 1 illustrates the large number of consonants that reside in the high frequencies.
Further, the benefits of frequency-lowering technology should be validated with behavioral testing and feedback from parents, speech therapists, and teachers. Hearing aid manufacturers have developed numerous technologies to improve performance in noise, including directional microphones, digital noise reduction (DNR), wind noise reduction, and dereverberation algorithms. We know that incidental listening, the term used to describe a child’s tendency to listen to speech that is not directed specifically to him or her, is responsible for a great deal of a child’s vocabulary and social development. It is likely that there are differences in adaptive directional algorithms from one manufacturer to another, and consequently, there is not enough evidence to determine whether they are suitable for children.
Other studies have indicated that DNR provides at most a modest improvement, and in many cases, no change in speech understanding in noise (Bentler, 2005; Peeters 2009).
They also showed that children’s novel word learning abilities were improved with the use of DNR, a fact they attributed to a decrease in the cognitive processing load afforded by improved listening comfort associated with DNR.
The interested audiologist is referred to an excellent review by McCreery and colleagues on electroacoustic assessment of hearing aids with DNR (McCreery, Gustafson, & Stelmachowicz, 2010). Note how the binaural directional response is more focused on the sounds arriving from the front than the directional response achieved by the hearing aids in Figure 3B.
Furthermore, these systems typically use a carrier frequency that “hops” from frequency to frequency many hundred times per second, a characteristic that makes digital RF systems less susceptible to interference from nearby RF devices (Wolfe et al., in press). Additionally, make certain you see a licensed audiologist who is experienced with providing new technology for patients in your age range (or the range of your child).
In contrast, this group of adult hearing aid users achieved a 22% improvement when listening with both ears at the same time via wireless streaming that delivered the telephone signal to each hearing aid simultaneously. The examiners ensured that the children perceived the recorded speech from the telephone to be comfortably loud.
In summary, performance with use of DuoPhone in both quiet and in noise was significantly better than performance in the monaural condition.
For example, truck drivers in North America not infrequently have a greater degree of hearing loss in their left ear (when the window is rolled down the left ear would be exposed to more sound from the engine). In the last resort the whole inner ear can be destroyed surgically by a procedure called a labyrinthectomy. Exploration of the middle ear surgically with correction of the ossicular chain or insertion of a prosthesis is called an ossiculoplasty. On examination blood is usually seen in the middle ear behind the ear drum (a hemotympanum). The resultant hearing loss depending on the mechanism can be conductive, sensorineural or a combination thereof. Of interest the first course of cisplatinum often demonstrates which patients are vulnerable to cochlear damage and what may happen in future if continued treatment courses are required. ANs are overwhelmingly unilateral, but in association with a rare genetic disorder, neurofibromatosis type 2, they may be bilateral.
Another concept to appreciate is that the dB scale is a logarithmic (an exponentially increasing) rather than arithmetic (linear increasing) scale which makes it difficult to apply a percentage hearing loss to any individual. Certain anti- depressants (especially the tricyclic or SSRI classes) and anti-convulsants (medications used for seizure control) have been effective for some individuals.
Mean comfort levels (MCLa€™s) and uncomfortable loudness levels (ULLa€™s) during audiometry provide some information concerning the threshold intensity of sound an individual can tolerate. One general maxim in medicine is that a€?an unexplained unilateral sensorineural hearing loss should be considered an acoustic neuroma until proven otherwisea€?.
Continuous migration of epithelium from the deeper to the lateral portion of the ear canal tends to keep the ear clean.
The pars tensa or lower four-fifths of the ear drum is conically shaped and has a strong fibrous middle layer which provides strength. The blood supply to the incus can be tenuous compared to other structures of the middle ear.
Abnormalities in vestibular end organ function often result in the patient experiencing the subjective complaint of vertigo. In general terms the greater the frequency the higher the pitch of the sound and the greater the intensity the louder we hear it.
Of interest, in a parallel series of control patients who were further exposed to repeated episodes of acute acoustic trauma during the same study period by the end of 4 years 30% of these individuals had demonstrated significant hearing deterioration.
A testing protocol that requires adolescents to fail twice instead of once will reduce false positives. Severe forms of diabetic nerve disease often necessitate amputation of the lower extremities. No significant differences were found between participant groups on the HHIE-S; however, regarding hearing aid usage, mixed differences were found. Anecdotally, the percept is that because of noise exposure experienced in the military service, veterans have more hearing loss than do nonveterans.
Finally, from Table 2, the two groups of participants did not differ in the rates at which either dizziness or tinnitus had been experienced in the past year. And even for those that do, at a time when prospective hearing aid purchasers are being inundated with new information, anxious about the test results, and worried about the cost involved, much of this explanation will be forgotten or misconstrued the time several weeks have passed. Indeed, the ability to take advantage of these cues may help explain why some people seem to understand speech much better than one would predict on the basis of their audiogram. There are, unfortunately, many people with audiograms similar to this who do not, for one reason or another, wear hearing aids. And we know from many years of research, that consonants contribute more to the understanding of speech than vowels.
In truth, they may be hanging on to speech comprehension with their finger tips; any further distortion in the speech signal, such as someone talking rapidly or in a foreign accent, or in the presence of noise and reverberation, and they lose it.
These people depend upon whatever low frequency energy they do receive for comprehending speech. And this person is missing just too much of the speech signal to expect easy communication in any oral exchange. Or perhaps someone's hearing loss is described by employing a single figure (derived usually from averaging the hearing losses at 500 Hz, 1000 Hz, and 2000 Hz).
But it should be apparent, just from a visual inspection, that these two ears would perceive speech quite differently. All it would take would to resolve this verbal conundrum would be an understanding of what the audiogram actually signifies (degree of hearing loss across frequency).
While most people exhibit a gradually sloping hearing loss across frequency (such as in figure 1), some people have audiograms that are very atypical. Hearing losses greater than about 70 dB may produce qualitatively different effects than losses less than this.
In brief, the audiogram is perhaps the most important indictor of one's hearing function, the particulars of which everybody who has a hearing loss should be aware of. First, turn down the volume on your mp3 player and give your ears a break some time during the day. Most studies have shown no degradation in speech recognition in noise for adults using DNR. The best technology in the world can be worthless if it is not selected and fitted appropriately to meet the wearer’s needs.
All things being equal most noise in industry however is a combination of primary continuous and superimposed impact type noise. Those who fire guns often demonstrate a greater degree of hearing loss in the ear closest to the barrel (the left ear in a right-handed shooter) because that ear would be closest to the explosion and the other ear would be protected by a a€?head shadowa€?.
However the natural history is enigmatic with unpredictable periods of exacerbation and remission. For example the difference between 10 and 40 dB in sound pressure intensities is not a 4xa€™s increase but actually an increase by a factor of 1,000 or 103 in sound pressure intensities! An experienced tester, typically an audiologist, is required to perform these technically demanding tests. Wax and debris can collect in the ear canal when this migratory mechanism fails or is overloaded from infectious or inflammatory conditions. The pars flaccida or upper one-fifth is less distinct and has a poorly developed middle fibrous layer.
When pathology affects its blood supply it can lead to the erosion of its long process which is attached to the stapes.
Diabetic autonomic neuropathies can affect cardiovascular, gastrointestinal, bladder, and erectile function.
Given the increasing prevalence of obesity, however,  it is likely that these figures provide an underestimate of future diabetes prevalence. To date, no studies have focused on the prevalence of hearing loss among the veteran population. In this context, a veteran refers to anyone who served in any branch of the military services. Word-recognition in quiet and in competing message were evaluated on one ear with the Department of Veterans Affairs (VA) female speaker version [14-15] of Northwestern University Auditory Test No.
I know that I'm often bemused when I hear what some people recount to me what they think their audiologist told them about their audiogram and its implications.
Only the shaded area of the speech banana above the threshold curve is audible; portions below will not be perceived. Still, there are certain anchor locations for all speech sounds, as displayed on the speech banana, and these can offer valuable insights in understanding the effects of differing hearing losses. And this audiogram depicts only a gradual high frequency hearing loss; were this person's audiogram something like the one shown in figure 2, problems with speech perception would be even more severe. The presence of noise and reverberation (not exactly an uncommon occurrence in our society!) would have a disproportionate effect on them, since it would mask the only speech energy they are able to receive.
Quite clearly this example demonstrates that the shorthand description of a hearing loss with a number or a verbal label can be quite deceptive.
This would include people with rising thresholds with frequency as well as those with perfectly normal hearing at the very low and high frequencies, but with moderately or severe hearing losses in the mid frequencies. In this instance, it would be more of a challenge to package sound within this more restricted dynamic range (this is where advanced technology can be very helpful, as in hearing aids with fast acting automatic gain control circuits). Research has determined if you were working in an environment that was as loud as your player, the government regulations would limit you to only 1 hour of listening at 70% of the maximum volume level. And if you play an instrument, there are a number of strategies that can be used to reduce the chance of noise injury. More recently, Wolfe and colleagues (submitted, 2013) compared aided thresholds and speech recognition for a group of children who had mild hearing loss and used hearing aids with NLFC and extended bandwidth. Carol Flexer has estimated that as much as 90% of what a child learns during the first few years of life comes from incidental listening (Cole & Flexer, 2010). This makes the pars flaccida especially susceptible to negative middle ear pressure and prone to retractions that can lead to the formation of retraction pockets. Another structure called Reissnera€™ s membrane (R) forms the roof of the scala media (M) which separates this from the scala vestibuli (V). In complex sounds the interaction of its pure tone components forms the basis of its complexity or its psychological counterpart known as timbre. Of the 3,753 EHLS participants, 1,021 (27.2%) reported military service with 22 females and 999 males. After that point, people will usually begin to display some communication difficulties because of the elevated hearing thresholds.
In spite of portrayals to the contrary on some charts, no speech sound can be pinpointed to a speech point on the audiogram; all of them spread their energy somewhat along some segment of the frequency spectrum.
For example people with an average 40 dB hearing loss are considered to have just a moderate hearing loss. The varieties are almost (but not quite) endless and many of these differences have behavioral implications.
A hearing loss may also involve central auditory pathways and these, too, may affect speech perception quite severely.
NLFC provided better access to low-level high-frequency sounds as well as better recognition of high-frequency speech sounds when compared to hearing aids with extended bandwidth. Could directional microphones, which inherently limit access to sounds arriving from behind a child, interfere with incidental listening? When retraction pockets fail to be self-cleansing they fill with debris and desquamated skin that can lead to secondary infection and bone erosion better known as cholesteatoma. Because the 22 females were a substantial minority (2.2%), only the data from 1,589 males (veterans and nonveterans) were analyzed. The ear selected for word recognition was either the ear with better (lower) pure tone thresholds or the right ear (RE) if the pure tone thresholds were equal. The higher the number, the greater the impact of the hearing loss (referring only to the unaided condition). But such a shorthand label does not reflect the pattern of a hearing loss, a pattern, as we have seen, that may lead to more insights into the behavioral implications of a hearing loss. Nevertheless, in spite of all these caveats, the audiogram is still the most fundamental auditory dimension of all.
When the ears are exposed to noise over a number of years, it will eventually lead to loss of hearing.
In quiet, the word-recognition materials were presented nominally 36 dB above the 2,000 Hz threshold in the test ear. The 100 dB point should not be confused with a 100% hearing loss, which is a total lack of hearing.
Of the veterans, 70.3 percent served during wartime, most of which were in World War II (n = 396), Korea (n = 220), and Vietnam (n = 86). Hearing sensations do continue past this point, with some audiometers extending this vertical range to 120 dB. In a slightly different viewpoint in this article, pure tone thresholds are considered but one domain of auditory function with other domains, including word recognition in quiet and the word recognition in the competing message. The prevalence of hearing loss in the nonveteran and veteran populations of the Beaver Dam cohort was examined in these three domains of auditory function.
The analyses used the chi-square test of association for categorical variables, the Mantel Haenszel chi-square test of trend for ordinal data [17], and t-tests of mean differences for continuous data (SAS Institute, Inc; Gary, North Carolina).



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