Schizophrenia and working memory

Researchers at MAPrc have published a pair of research papers providing crucial proof-of-principle for a new treatment for cognitive impairment in schizophrenia.  Cognitive impairment is a core symptom of schizophrenia, occurring in greater than 80% of patients, and results in considerable functional disability. Despite the prevalence and significant burden associated with these symptoms, treatment options are few and of limited effectiveness.

MAPrc researchers, led by Dr Kate Hoy, undertook a world-first proof-of-concept study into the effects of a type of non-invasive brain stimulation called transcranial Direct Current Stimulation (tDCS) working memory performance in patients with schizophrenia.  tDCS was applied to the prefrontal cortex of 18 patients and following 20 minutes of active stimulation, as compared to sham, there were significant improvements in working memory over 40 minutes following stimulation. These findings were highly consistent, with over 70% of patients showing some degree of improvement compared to sham.

The investigation also looked at whether tDCS had any effect on the underlying brain activity thought to be responsible for working memory impairment in schizophrenia (i.e. gamma synchrony). It was found that tDCS did in fact result in significantly increased gamma synchrony, and that this was correlated with the significant behavioural improvement. These findings indicate that tDCS may indeed be enhancing working memory performance in schizophrenia by modulating the underlying brain activity associated with impairment.

These findings represent a critical first step in the development of a highly promising novel treatment approach. MAPrc researchers are now undertaking the next stage of this research which aims to provide information regarding the clinical value of this treatment approach, specifically investigating repeated sessions of tDCS to assess the duration of improvement and subsequent impact on functional outcomes. This work could pave the way for clinical translation of the first novel treatment for cognitive impairment SCZ in decades; and has potential to do so in the short-term.

Reference: Hoy, K. E., Bailey, N. W., Arnold, S. L., & Fitzgerald, P. B. (2015). The effect of transcranial Direct Current Stimulation on gamma activity and working memory in schizophrenia. Psychiatry research.

Reference: Hoy, K. E., Arnold, S. L., Emonson, M. R., Daskalakis, Z. J., & Fitzgerald, P. B. (2014). An investigation into the effects of tDCS dose on cognitive performance over time in patients with schizophrenia. Schizophrenia research, 155(1), 96-100.