Cognitive impairment is a core symptom of schizophrenia and is in a large part responsible for the poor psychosocial outcome of the disorder. The use of non-invasive brain stimulation techniques as a therapeutic option is just commencing for neuropsychiatric patients. Concerning healthy subjects the investigators have previously shown that anodal tDCS to the right dorsolateral prefrontal cortex (DLPFC) parallel to working memory training can sustainingly enhance performance in a spatial n-back task. Additionally, first translational experiments regarding the use of anodal tDCS to improve working memory (WM) in patients with schizophrenia rendered promising results. On those grounds, the investigators now test the hypothesis that anodal tDCS to the right DLPFC can augment working memory training in patients with schizophrenia.
Name: active tDCS
Name: sham tDCS
Name: Adaptive working memory training
Description: Use of d' and response time as dependent variables. Based on signal detection theory, the discriminability index d' (d-prime) is calculated by using the formula d' = Z(hit rate) - Z(false alarm rate).
Measure: Change (post training - pre training) in working memory task performance (1-,2-,3-back). Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of working memory training.Description: Trail Making Test (TMT) A and B. Results in seconds will be normalized by age and education adjusted standard values. Slower processing time indicates less cognitive flexibility and processing speed.
Measure: Change (post training - pre training) in cognitive flexibility and processing speed. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training. And changes in follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Trail Making Test (TMT) A and B. Results in seconds will be normalized by age and education adjusted standard values. Slower processing time indicates less cognitive flexibility and processing speed.
Measure: Change (follow-up - pre training) in cognitive flexibility and processing speed. Time: Pre Training: 3-4 days before training start. Follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Measure of different cognitive domains with the Brief Assessment of Cognition in Schizophrenia (BACS). Subscales (Verbal Memory, Working Memory, Motor Function, Verbal Fluency, Speed of Processing, Executive Function) and composite score. Taking age and gender into account, individual test scores are averaged to standardized scores (z-score) . Higher scores indicate better task performance.
Measure: Change (post training - pre training) in cognition. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training. And changes in follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Measure of different cognitive domains with the Brief Assessment of Cognition in Schizophrenia (BACS). Subscales (Verbal Memory, Working Memory, Motor Function, Verbal Fluency, Speed of Processing, Executive Function) and composite score. Taking age and gender into account, individual test scores are averaged to standardized scores (z-score) . Higher scores indicate better task performance.
Measure: Change (follow-up - pre training) in cognition. Time: Pre Training: 3-4 days before training start. Follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Use of the d' and response time as dependent variables. Based on signal detection theory, the discriminability index d' (d-prime) is calculated by using the formula d' = Z(hit rate) - Z(false alarm rate).
Measure: Change (follow-up - pre training) in working memory task performance (1-,2-,3-back). Time: Pre Training: 3-4 days before training start. Follow up: 4 and 12 weeks after completion of working memory training.Description: Calgary Depression Scale for Schizophrenia (CDSS). Maximum score is 27. Higher scores indicate a higher level of depression.
Measure: Change (post training - pre training) in depressive symptoms. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training.Description: Calgary Depression Scale for Schizophrenia (CDSS). Maximum score is 27. Higher scores indicate a higher level of depression.
Measure: Change (follow-up - pre training) in depressive symptoms. Time: Pre Training: 3-4 days before training start. Follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Positive and Negative Syndrome Scale (PANSS). The PANSS measures symptom severity on a positive, a negative and a general psychopathology scale. Higher scores indicate more pronounced symptom severity. The PANSS will be analyzed in subscales and as a summed total score.
Measure: Change (post training - pre training) in psychopathology. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training. And changes in follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Positive and Negative Syndrome Scale (PANSS). The PANSS measures symptom severity on a positive, a negative and a general psychopathology scale. Higher scores indicate more pronounced symptom severity. The PANSS will be analyzed in subscales and as a summed total score.
Measure: Change (follow-up - pre training) in psychopathology. Time: Pre Training: 3-4 days before training start. Follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Scale for the Assessment of Negative Symptoms (SANS). The total score is calculated by addition of 5 subscales with a maximum score of 25. A higher score indicates more pronounced negative symptoms.
Measure: Change (post training - pre training) in negative symptoms Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training.Description: Scale for the Assessment of Negative Symptoms (SANS). The total score is calculated by addition of 5 subscales with a maximum score of 25. A higher score indicates more pronounced negative symptoms.
Measure: Change (follow-up - pre training) in negative symptoms Time: Pre Training: 3-4 days before training start. And changes in follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: World Health Organization Quality of Life Questionnaire, short version (WHOQOL-BREF). Four major domains are assessed: physical, psychological, social relationships and environment. It consists of 26 items and a maximum score of 130. Higher scores indicate a higher quality of life.
Measure: Change (post training - pre training) in quality of life. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training.Description: World Health Organization Quality of Life Questionnaire, short version (WHOQOL-BREF). Four major domains are assessed: physical, psychological, social relationships and environment. It consists of 26 items and a maximum score of 130. Higher scores indicate a higher quality of life
Measure: Change (follow-up - pre training) in quality of life. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training. And changes in follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS).Scale with 21 items, maximum score of 84, higher scores indicate more subjective cognitive impairment.
Measure: Change (post training - pre training) in subjective cognitive capacity. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of training.Description: Subjective Scale to Investigate Cognition in Schizophrenia (SSTICS).Scale with 21 items, maximum score of 84, higher scores indicate more subjective cognitive impairment.
Measure: Change (follow-up - pre training) in subjective cognitive capacity. Time: Pre Training: 3-4 days before training start. Follow-up sessions: 4 and 12 weeks after completion of working memory training.Description: resting state connectivity, event-related potentials (ERP), 32-channel EEG
Measure: Differences in EEG signatures between interventional arms. Time: Pre Training: 3-4 days before training start. Post Training: 3-4 days after completion of trainingDescription: Examination of gene polymorphisms (BDNF Val66Met, COMT Val108Met158; CACNA1C) via polymerase chain reaction (PCR).
Measure: Influence of genetic constitution on tDCS effectiveness Time: Pre Training: 3-4 days before training startDescription: Age in years; demographic questionnaire
Measure: Influence of age on tDCS effectiveness Time: Pre Training: 3-4 days before training startDescription: Sex: male, female, not specified; self report questionnaire
Measure: Influence of sex on tDCS effectiveness Time: Pre Training: 3-4 days before training startAllocation: Randomized
Parallel Assignment
There is one SNP
Examination of gene polymorphisms (BDNF Val66Met, COMT Val108Met158; CACNA1C) via polymerase chain reaction (PCR).. Influence of age on tDCS effectiveness. --- Val66Met ---