IS 33. NBS in schizophrenia

Abstract

Background Working memory represents a core cognitive domain that is impaired in schizophrenia for which there are currently no satisfactory treatments. Repetitive transcranial magnetic stimulation (TMS) targeted over the dorsolateral prefrontal cortex (DLPFC) has been shown to modulate neurophysiological mechanisms linked to working memory in schizophrenia and improves working memory performance in healthy subjects, and may therefore represent a treatment modality for schizophrenia patients. Objectives To evaluate the effects of rTMS on working memory performance in schizophrenia patients; and evaluate if rTMS normalizes performance to healthy subject levels. Design 4-week randomized double-blind sham-controlled pilot study design. Setting Centre for Addiction and Mental Health (a university teaching hospital that provides psychiatric care to a large urban catchment area and serves as a tertiary referral centre for the province of Ontario). Participants 27 medicated schizophrenia patients performed the verbal working memory N-back task before and after rTMS. Intervention rTMS was targeted bilaterally sequentially to left and right DLPFC 750 pulses per side at 20 Hz for 20 treatments using MRI-targeted methods. Main outcome measures Mean magnitude of change in the N-back accuracy for target responses with active (n = 13) or sham (n = 12) rTMS treatment course. Results rTMS significantly improved 3-back accuracy for targets compared to placebo sham. The improvement in 3-back accuracy was also found to be at a level comparable to healthy subjects. Conclusions These pilot data suggest that bilateral rTMS may be a novel, efficacious, and safe treatment for working memory deficits in patients with schizophrenia. rTMS for the treatment on neurophysiology and non-cognitive symptoms for schizophrenia will also be reviewed in the context of this trial.