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It is estimated that 18,000 people have noise induced hearing loss (NIHL) caused or made worse by work in the UK.
When we are exposed to potentially harmful noise, sensitive structures in our inner ear can be damaged.
The meters that we use to measure noise mimic the human ear, which is more sensitive to some sounds than others. The minimum change that a human ear can detect is about 3dB, however, on average a person perceives a change in sound level of about 10dB as a doubling (or halving) of the sounds loudness. Taking the actual measurement of sound and human perceived loudness into the work environment can have an impact on how we respond to noise as individuals, and would allow a better understanding of the damage that noise may cause to individuals when there are very small increases in noise levels. Although being aware of decibel levels is an important factor in protecting an individual’s hearing, distance from the source of sound and duration of exposure are equally important. For some people the problem of loss of hearing is severe enough to impact their everyday life. In a work environment the individual may not be able to hear important information as part of a meeting, and it may cause interpersonal problems that can cause frustration and stress.
As we have seen, long term exposure to sounds over 80dB (A) can damage your ears, it is therefore essential that employers comply with the Control of Noise at Work Regulations 2005 in order to protect their workers from NIHL.
Is the noise intrusive — like a busy street, a vacuum cleaner or a crowded restaurant — for most of the working day? Do your staff have to raise their voices to carry out a normal conversation when about two metres apart for at least part of the day?
Noise measurements must be made by competent people, who have been trained in the techniques of noise measurement and have experience of assessing noise. If noise needs to be controlled, you’ll need to make sure that the controls are put in place and work. Where noise levels still exceed 85dB (A) ensure workers wear hearing protection (ear plugs or earmuffs) within the designated and clearly marked zones.
Where hearing protection is used, it needs to be selected to give enough protection to get below 85dB (A) at the ear. Have a “blanket” approach to hearing protection, it is better to target its use and only encourage people to wear it when they need to. PDF access policyFull text access is free in HTML pages; however the journal allows PDF access only to subscribers. Margaret I Lomax, Tzy-Wen L Gong, Younsook Cho, Li Huang, Seung-Ha Oh, Henry J Adler, Yehoash Raphael, Richard A AltschulerPMID:12689446Acoustic overstimulation has very different outcomes in birds and mammals.
Kohei Kawamoto, Sho Kanzaki, Masao Yagi, Timo Stover, Diane M Prieskorn, David F Dolan, Josef M Miller, Yehoash RaphaelPMID:12689447Environmental inner ear insults often lead to hair cell injury and loss. Knowing how to determine which HPD does its job the best requires the user to rely upon the manufacturersa€™ published performance data, a little knowledge of the acronyms and a few tricks of the trade. PNR is the reduction of unwanted sounds (noise) through the use of passive materials such as foam and silicone.
ANR is the electro-acoustic reduction of unwanted sounds (noise) through the use of electronics, traditionally analogue, or more advanced digital processing.
HPDs are designed to prevent hearing damage, but having usersa€™ ears covered degrades their ability to hear naturally. To try and overcome this effect of the HPD, communication headsets quite often provide a means of replicating the sounds external to the headset so the user can have normal conversations while still wearing the headset as well as maintaining their situational awareness. Mechanical talk-through systems use a mechanical acoustic valve that closes when it detects a specific sound pressure level.
Electrical systems provide a means of reproducing the sounds inside the headset or earpiece. PROs: The two important aspects of impulse protection relate to the speed of response to the impulse noise and the treatment of the sound during the impulse event. High levels of impulse protection are provided by good PNR and effective Talk-Through control. The Noise Reduction Rating is the most common way for manufacturers to detail the performance of their HPD. Traditionally, NRR figures are measured in accordance with American National Standards Institute (ANSI) S3.19-1974.
Since rating methods are based upon idealized laboratory testing, some have criticized the NRR and SNR for being too generous in its prediction of noise reduction (attenuation).
In an effort to bring the Noise Reduction Rating more in line with real-world usage, the United States Environmental Protection Agency (EPA) has proposed a new regulation for the testing and labelling of HPDs.
The proposed method will use a new ANSI-standard lab test protocol, ANSI S12.6-2008 (Supervised Subject Fit), to generate the attenuation ratings. Most recently, Nacre independently tested its QUIETPRO Intelligent Hearing System to the proposed new ANSI S12.6-2008 Method A protocol. If you are involved in military operations, the chances are rather high that you will require a Hearing Protection Device. 6 The Detection Question – Absolute Threshold: Absolute threshold is the weakest level of stimulus that can be detected 50% of the time. 8 Why does signal detection theory appear to be more credible than absolute threshold theory?
10 Subliminal Messages: Subliminal techniques have occasionally been used in advertising, propaganda, and even music. 11 The Difference Question – Just noticeable difference: A difference threshold is the minimum difference between two stimuli that is detected 50% of the time. 12 Weber’s Law: Weber’s Law – Difference thresholds increase in proportion to the size of the stimulus. 14 Sensory Adaptation: Sensory adaptation is the disappearance to repetitive or unchanging stimuli Think about a hot tub – when you first get in, you think it is really hot. 16 Hearing 101: Sight will always been our most used sense, though hearing is a close second Hearing (audition) is most helpful for language transmission So, how does the process of hearing work? 19 Physical Characteristics of Sound Waves Wavelength - distance in one cycle of a wave, from one crest to the next Amplitude is the amount of energy in a wave, its intensity, which is the height of the wave at its crest (dB) Frequency is the number of times a sound wave cycles in one second Pitch – The highness or lowness of the sound (Hz) Timbre (pronounced “TAM-bur”) The distinguishing quality of sound Can you tell the difference between a trumpet playing a C# and a guitar playing a C#? 25 Locating Sounds: Sound Localization Sound Localization – the process by which you determine the location of a sound. 32 An Eye on the World Retina Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision. 36 Trichromatic Theory Young (1802) & von Helmholtz (1852) both proposed that the eye detects 3 primary colors: red, blue, & green All other colors can be derived by combining these three. Authors of the research paper Noise-induced hearing loss in the 21st Century from the World Journal of Otorhinolaryngology (WJO) confirm that it is the second most common form of hearing loss, after age-related hearing loss, yet 100% preventable.
NIHL can be caused by a one-time exposure to an intense “impulse” sound such as an explosion, or by a continuous exposure to loud sounds over an extended period of time, such as noise generated in a woodworking shop. These sensitive structures, called hair cells, are small sensory cells that convert sound energy into electrical signals that travel to the brain.
0dB is the lowest threshold of human hearing, with normal speech having a sound level of approximately 60dB.
Noise measurements at work are usually shown as dB(A), which means they directly relate to what we hear. We know that people who are exposed to 80 dB(A) for eight hours a day are likely to suffer harm to their hearing.
A decrease in sound level of 10 dB actually represents a 90% decrease in sound intensity, but only a 50% decrease in perceived loudness because of the nonlinear response of the human ear. When a person is exposed to loud noises over a long period of time, symptoms of NIHL will increase gradually.
Many people find that they feel isolated, and frustrated at not being able to be involved in a conversation. They will be able to use the readings to decide whether the noise levels need to be controlled and how.
When choosing hearing protection consideration should be given to the comfort and fit for the user, hygiene, and whether the protection has to be worn with other protective equipment.
Claims cost insurers ?70 million per year, however the number of claims has reduced over the last few years.
However, the changes in gene expression that underlie these biological changes are poorly understood.
When noise exposure kills hair cells in birds, these cells can regenerate and hearing will recover. ROS can cause oxidative damage to diverse cellular components, including membranes, proteins, and DNA, if they are not "neutralised" by antioxidant defences. Fibroblast growth factor-2 (FGF-2) can protect hair cells from neomycin ototoxicity in vitro, and in vivo study has shown upregulation of FGF receptor­3 in the cochlea following noise exposure, suggesting that some FGF family members might play a role in protection or repair of the cochlea from damage. The permanent hearing threshold shift (PTS) was measured 1 week post-exposure, using auditory brain stem response audiometry (frequency range, 0.5-32 kHz). This sound is processed through the electronics and inverted so that it is 180 degrees out of phase with the original noise, and matched so the relative amplitudes of the signals are the same.
The practical application presents several problems and if not addressed will lead to instability and poor performance. A microphone on the outside of the headset listens to the sound; the system then processes it through the use of electronics and presents it to the user through a loudspeaker.
The QUIETPRO Intelligent Hearing System uses a specifically-designed Application Specific Integrated Circuit (ASIC) that performs both digital ANR and talk-through impulse protection.


It is becoming more common for headsets to use commercial off-the-shelf Digital Signal Processing (DSP) integrated circuits for this purpose.
Beware though, the NRR figure only applies to PNR and does not consider the contribution of ANR on an HPDa€™s performance. The European standard EN352-2 provides a Single Number Rating (SNR) figure that manufactures sometimes use instead of the NRR figure (one of those tricks of the trade). Studies indicate that while some users in real-world applications achieve these ratings, many users do not. It will now provide an indication of how much attenuation minimally-trained users (the lower number) versus highly-motivated trained users (the higher number) can expect to achieve.
The initial results showed that in its lower number, it could achieve 33 dB of noise reduction, and 40 dB in its high range. Depending upon their role, some users may even need the a€?bells and whistles.a€™ Be sure to select the appropriate device for your needs. Discuss basic principles of sensory transduction, including absolute threshold, difference threshold, signal detection, and sensory adaptation. The purpose, effectiveness, and the frequency of the application of such techniques is debated. Example: When you are in a noisy environment you must shout to be heard while a whisper works in a quiet room. When you “hear” a sound, your ear picks up the sound waves and converts them into neural impulses that you perceive as music or language.
There is a split second delay on sounds that are coming at you from the left or right side because both ears hear the sound differently. Place Theory – The position on the basilar membrane at which waves reach their peak depends on the frequency of a tone. Sound levels above 120dB can be uncomfortable, with sound levels between 130 to 140 dB being painful. What seems like small differences in numbers are really big changes in how much noise people are exposed to. Over time, the sounds a person hears may become distorted, and it may be difficult for the person to understand speech. As a simple guide you will probably need to do something about the noise if any of the following apply.
But it is likely that you will need to have the noise levels measured, using a sound meter. Although, it is thought that the reduction in claims is partly inspired by reform in insurance legislation in 2013 rather than in better controls. Our approach to investigating this problem is to use gene microarrays to measure the changes in gene expression in the chinchilla inner ear following a 3 h or 6 h noise exposure (95 dB SPL, 707-1414 Hz).
Several reports have demonstrated the applicability of growth factors for hair cell protection. We therefore examined if FGF­1 and FGF-2 chronically delivered to the cochlea prior to noise overstimulation can attenuate noise-induced hair cell damage in vivo under conditions in which GDNF and NT-3 were effective.
The total Mg concentrations of perilymph, cerebrospinal fluid and plasma were analyzed by atomic absorption spectrometry. The headset then plays this anti-phase noise through a loudspeaker within the ear piece so that the original and anti-phase noises cancel out each other. Broadband noise, that is noise made up of many frequencies of different amplitudes, differentiates ANR technologies and reveals the benefit of digital ANR processing. The purpose-built processing engine works entirely in the digital domain - not analogue, therefore operating faster than standard DSP or analogue circuits. These DSP devices essentially perform in the same way as their analogue equivalents; they do however allow the noise threshold a€?triggera€™ level to be programmed by the manufacturer.
This has led to a variety of inappropriate de-rating methods for hearing protectors, and has contributed to much confusion in knowing how to accurately estimate a hearing protectora€™s attenuation. While it will still be known as the NRR, this new rating will now represent a two-number range of expected protection, as opposed to a single-number estimate. Insist that the manufacturers provide you all pertinent information with the product, most importantly the NRR independently tested in accordance with the new standard. Example: If a person turns up your IPOD just a hair, you probably will not hear the difference (even though there is one) Subliminal messages are perceived below your absolute threshold. Just-noticeable difference Example: Car stereo – how much do you have to turn up the volume to notice a “real” difference? Transduction – The transformation of stimulus energy to the electrochemical energy of neural impulses. Care should be taken to provide protectors that do not cut out too much noise, as this can cause isolation or lead to an unwillingness to wear them.
There is very little information on the impact of NIHL on the economy, however, the overall impact of hearing loss on the UK economy has been estimated at ?25 billion. This noise exposure causes a temporary threshold shift (~40 dB) and a temporary reduction in distortion product otoacoustic emissions (DPOAE), but no permanent hearing loss or hair cell loss. Changes in gene expression form the basis for important biological processes, including repair, regeneration, and plasticity.
The goal of the experiments presented here was to assess the protective capability of the human GDNF transgene against noise trauma in the guinea pig cochlea.
These metalloenzymes work together to regulate ROS production in virtually every cell in the body, and they may be important for limiting cochlear damage associated with aging and acoustic overexposure. To achieve this seal either the around-the-ear headset conforms to the users head well and clamps tightly, or the in-ear ear tip (foam, silicon flange or custom silicon earplug) is fitted well inside the ear canal without any noise leaks. If the ANR system started adding the noises together because it did not process the sound quickly enough, the result would be similar to the screeching a€?feedbacka€™ sound experienced when putting a microphone next to a loudspeaker in a public address system. The term a€?Activea€™ headset is sometimes used to describe the electronic impulse protection or more accurately the Talk-Through control. This causes three tiny bones called the ossicles (hammer, anvil, stirrup) in your middle ear to vibrate 3.
It is clear that any hearing loss has a massive impact on the quality of life of individuals. Here, we present data showing (1) the suitability of mouse and human complementary DNA (cDNA) clones for detecting chinchilla cochlear gene transcripts, and (2) the change in cochlear gene transcripts in noise exposed chinchillas. We are therefore using a battery of molecular approaches to identify and compare changes in gene expression following noise trauma in birds and mammals.
The left ears of guinea pigs were inoculated with a recombinant adenovirus with a human GDNF insert (Ad.GDNF).
In this chapter, we describe a series of experiments using mice with targeted deletions of Sod1 or Gpx1, the mouse genes that code for SOD1 and GPx1, respectively, to study the cellular mechanisms underlying noise-induced hearing loss (NIHL).
The effect is that the speed of response to the impulse event is ultra quick a€“ stopping only the unwanted noise and quickly restoring full natural hearing.
Yes Signal detection theory – There is no absolute threshold – fatigue, motivation, and expectations can change this.
Work related hearing loss is entirely preventable, and therefore employers can help themselves in reducing their own costs by putting in place robust noise protective measures, that will prevent their staff from losing their hearing. Chinchilla cochlear transcript probes exhibited strong and discrete signals on both mouse and human cDNA filter arrays.
Both differential display and subtractive hybridisation were used to identify genes whose expression increased in the chick basilar papilla immediately following exposure to an octave band noise (118 dB, centre frequency 1.5 kHz) for 4-6 hr. The results from Sod1 and Gpx1 knockout mice provide insights into the link between endogenous levels of antioxidant enzymes and susceptibility to NIHL. Threshold shifts 10 days postexposure were essentially equivalent at all frequencies tested across different treatment groups. With the QUIETRPO, it is still possible for the user to hear sounds around them even during the impulse noise event. Inside the cochlea is the basilar membrane with hair cells that are bent by the vibrations and transduce this mechanical energy to electrochemical neural impulses.
Since the strongest hybridization occurred with mouse clones, mouse cDNA microarrays were used to study noise-induced changes in gene expression. Among those upregulated genes were two involved in actin signalling: the CDC42 gene encoding a Rho GTPase, and WDR1, which encodes a protein involved in actin dynamics. One week later, animals were sacrificed and hair cells counted in the left (inoculated) and right (non-inoculated) ears. No significant difference in threshold shifts was observed between the treated and untreated ears in any of the groups. The PTS and the perilymph Mg level showed a close negative correlation, suggesting that the intracochlear Mg level plays an important role in bringing about these protective effects. Chinchilla cDNA probes were differentially labelled with Cy3 (control) or Cy5 (noise exposed) by random primed synthesis, hybridized to 8750 mouse cDNAs arrayed on microscope slides and analysed by laser fluorescent microscopy.
Auditory brainstem thresholds were measured before the inoculation and just prior to sacrifice.
In a second series, we tested the therapeutic efficacy as a function of the post-exposure time of onset of the optimal Mg treatment (1 min, 2 and 4 hours), using normal Mg animals. Finally, auditory neurons stimulate the auditory nerve which transmits sound messages through your medulla, pons, and thalamus to the auditory cortex of the temporal lobes.
Several classes of genes exhibited time-dependent up regulation of transcription, including those involved in protein synthesis, metabolism, cytoskeletal proteins, and calcium binding proteins.


A fourth gene encodes a cystein-rich secreted protein that may interact with calcium channels. These findings indicate that exogenous FGF-1 or FGF-2 does not influence noise­induced hair cell damage under the experimental conditions used in this study, suggesting that these FGFs are not good candidates as auditory hair cell protectors in vivo. The therapeutic effect decreased with the length of time elapsed between the end of exposure and the beginning of treatment.
The results are discussed in relationship to previous studies showing noise-induced changes in structural proteins, calcium binding proteins, metabolic enzymes and membrane bound vesicles. To examine the mammalian response, gene microarrays on nylon membranes (Clontech Atlas Gene Arrays) were used to examine global changes in gene expression 30 minutes after TTS (110 dB broadband noise 50% duty cycle) or PTS (125 dB, 100% duty cycle) noise overstimulation (each for 90 minutes) in the rat cochlea. The results show that intracochlear inoculation with adenovirus into normal ears does not compromise hair cell counts and ABR thresholds.
In a parallel scanning electron microscopic test, we also found a Mg-related difference in the susceptibility of hair cell stereocilia to impulse noise exposure. It appears as hard nodules in the helix or antihelix and may discharge chalky white crystals through the skin. The data demonstrate the general feasibility of gene therapy for over-expression of neurotrophic factors against noise trauma, and emphasize the complexity of the technique and the problems of variability between subjects. It usually develops after chronic sustained high blood levels of uric acid.4Basal Cell Carcinoma. Histologi- cally, it is usually either (1) an epidermoid cyst, common on the face and neck, or (2) a pilar (trichilemmal) cyst, com- mon in the scalp.
Such nodules may antedate the arthritis.7Normal Eardrum This normal right eardrum (tympanic membrane) is pinkish gray.
The small blood vessels along the handle of the malleus are normal.8Perforation of the Drum Perforations are holes in the eardrum that usually result from purulent infections of the middle ear. They are classified as central perforations, which do not extend to the margin of the drum, and marginal perforations, which do involve the margin. The more common central perforation is illustrated here. A reddened ring of granulation tissue surrounds the perforation, indicating chronic infection. The membrane covering the hole may be exceedingly thin and transparent.9Tympanosclerosis In the inferior portion of this left eardrum, there is a large, chalky white patch with irregular margins. It is typical of tympanosclerosis: a deposition of hyaline material within the layers of the tympanic membrane that sometimes follows a severe episode of otitis media. It does not usually impair hearing and is seldom clinically significant. Other abnormalities in this eardrum include a healed perforation (the large oval area in the upper posterior drum) and signs of a retracted drum. A retracted drum is pulled medially, away from the examiner’s eye, and the malleolar folds are tightened into sharp outlines.
The short process often protrudes sharply, and the handle of the malleus, pulled inward at the umbo, looks foreshortened and more horizontal.10Serous Effusion Serous effusions are usually caused by viral upper respiratory infections (otitis media with serous effusion) or by sudden changes in atmospheric pressure as from flying or diving (otitic barotrauma). The eustachian tube cannot equalize the air pressure in the middle ear with that of the outside air. Air is partly or completely absorbed from the middle ear into the bloodstream, and serous fluid accumulates there instead. Symptoms include fullness and popping sensations in the ear, mild conduction hearing loss, and perhaps some pain. Amber fluid behind the eardrum is characteristic, as in this patient with otitic barotrauma. A fluid level, a line between air above and amber fluid below, can be seen on either side of the short process. Air bubbles (not always present) can be seen here within the amber fluid.11Acute Otitis Media With Purulent Effusion Acute otitis media with purulent effusion is caused by bacterial infection.
Redness is most obvious near the umbo, but dilated vessels can be seen in all segments of the drum. Spontaneous rupture (perforation) of the drum may follow, with discharge of purulent material into the ear canal. Hearing loss is of the conductive type.
Acute purulent otitis media is much more common in children than in adults.12Bullous Myringitis Bullous myringitis is a viral infection characterized by painful hemorrhagic vesicles that appear on the tympanic membrane, the ear canal, or both. Symptoms include earache, blood-tinged discharge from the ear, and hearing loss of the conductive type. In this right ear, at least two large vesicles (bullae) are discernible on the drum. Causes include foreign body, otitis media, perforated eardrum, and otosclerosis of ossicles.14Pathophysiology of Sensorineural LossInner ear disorder involves cochlear nerve and neuronal impulse transmission to the brain. The inner ear or cochlear nerve is less able to transmit impulses regardless of how the vibrations reach the cochlea. The normal pattern prevails.22Angular Cheilitis Angular cheilitis starts with softening of the skin at the angles of the mouth, followed by fissuring. It may be due to nutritional deficiency or, more commonly, to overclosure of the mouth, as in people with no teeth or with ill-fitting dentures. Saliva wets and macerates the infolded skin, often leading to secondary infection with Candida, as seen here.23Actinic Cheilitis Actinic cheilitis results from excessive exposure to sunlight and affects primarily the lower lip. The lip loses its normal redness and may become scaly, somewhat thickened, and slightly everted. Because solar damage also predisposes to carcinoma of the lip, be alert to this possibility.24Herpes Simplex (Cold Sore, Fever Blister) The herpes simplex virus (HSV) produces recurrent and painful vesicular eruptions of the lips and surrounding skin.
Both of these stages are visible here.25Angioedema Angioedema is a diffuse, nonpitting, tense swelling of the dermis and subcutaneous tissue. Although usually allergic in nature and sometimes associated with hives, angioedema does not itch.26Hereditary Hemorrhagic Telangiectasia Multiple small red spots on the lips strongly suggest hereditary hemorrhagic telangiectasia. Affected people often have nosebleeds and gastrointestinal bleeding.27Peutz-Jeghers Syndrome When pigmented spots on the lips are more prominent than freckling of the surrounding skin, suspect this syndrome. Multiple intestinal polyps are often associated.28Chancre of Syphilis This lesion of primary syphilis may appear on the lip rather than on the genitalia. Because it is infectious, use gloves to feel any suspicious lesion.29Carcinoma of the Lip Like actinic cheilitis, carcinoma usually affects the lower lip. It may appear as a scaly plaque, as an ulcer with or without a crust, or as a nodular lesion, illustrated here. Fair skin and prolonged exposure to the sun are common risk factors.30Large Normal Tonsils Normal tonsils may be large without being infected, especially in children. The white marks are light reflections, not exudate.31Exudative Tonsillitis This red throat has a white exudate on the tonsils.
This, together with fever and enlarged cervical nodes, increases the probability of group A streptococcal infection or infectious mononucleosis.
The throat is dull red, and a gray exudate (pseudomembrane) is present on the uvula, pharynx, and tongue. The airway may become obstructed.35Thrush on the Palate (Candidiasis) Thrush is a yeast infection due to Candida. Among people with AIDS, the palate, as illustrated here, is a common site for this tumor.37Torus Palatinus A torus palatinus is a midline bony growth in the hard palate that is fairly common in adults. In this example, an upper denture has been fitted around the torus.38Fordyce Spots (Fordyce Granules) Fordyce spots are normal sebaceous glands that appear as small yellowish spots in the buccal mucosa or on the lips.
The rash of measles appears within a day.40Petechiae Petechiae are small red spots that result when blood escapes from capillaries into the tissues. Petechiae in the buccal mucosa, as shown, are often caused by accidentally biting the cheek. Oral petechiae may be due to infection or decreased platelets, as well as to trauma.41Leukoplakia A thickened white patch (leukoplakia) may occur anywhere in the oral mucosa. The extensive example shown on this buccal mucosa resulted from frequent chewing of tobacco, a local irritant. This kind of irritation may lead to cancer.42Marginal Gingivitis Marginal gingivitis is common among teenagers and young adults. The gingival margins are reddened and swollen, and the interdental papillae are blunted, swollen, and red.
Then the destructive (necrotizing) process spreads along the gum margins, where a grayish pseudomembrane develops. Causes include dilantin therapy (as in this case), puberty, pregnancy, and leukemia.45Pregnancy Tumor (Epulis, Pyogenic Granuloma) Gingival enlargement may be localized, forming a tumorlike mass that usually originates in an interdental papilla.
Note here the erosion of the enamel from the lingual surfaces of the upper incisors, exposing the yellow- brown dentin. This results from recurrent regurgitation of stomach contents, as in bulimia.48Abrasion of Teeth With Notching The biting surface of the teeth may become abraded or notched by recurrent trauma, such as holding nails or opening bobby pins between the teeth. The upper central incisors of the permanent (not the deciduous) teeth are most often affected. Together with the normal rough and coated areas, they give a maplike pattern that changes over time.51Hairy Tongue.
These dilatations of the lingual veins have no clinical significance.57Aphthous Ulcer (Canker Sore). Patches of any size raise the possibility of malignancy and require a biopsy.60Tori Mandibulares. Medially, note the reddened area of mucosa, called erythroplakia, suggesting possible malignancy.62Diffuse Enlargement.



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