ESPRIT (C2): Efficacy and mechanisms of transcranial direct current stimulation (tDCS)-enhanced cognitive training in schizophrenia

01/02/2015 to 31/01/2019

Impairments of cognition are a core, severely disabling feature of schizophrenia leading to poor long-term outcome with no established treatment available. Particularly impaired executive functions (e.g working memory) are frequently observed and are consistently associated with reduced activation of the dorsolateral prefrontal cortex (dlPFC). Deficits in those functions have been shown to be closely related to negative symptoms, thought disorder, and functional outcome in schizophrenia leading to the notion that frontal lobe dysfunction is crucially important in schizophrenic psychopathology. Cognitive training has been used to improve cognitive deficits in patients with schizophrenia. Noninvasive brain stimulation like tDCS can enhance executive functions like working memory in healthy subjects as well as in patients. Therefore, the specific combination of tDCS and cognitive training is promising to enhance the effects of cognitive training in schizophrenia. To identify the optimal parameters for this intervention in patients with schizophrenia, we first test the effects of different polarities, stimulation intensities and laterality on working-memory performance in a sham-controlled cross-over design (n=128). In the next step, we apply the most effective tDCS-parameters as identified in the previous experiments in an enhanced-training paradigm. In order to provide evidence for the specific effect of tDCS enhanced cognitive training we compare three conditions: i) working-memory training during tDCS, ii) working-memory training during sham-stimulation, and iii) tDCS alone.