Confirmatory Trial of Gamma Neurofeedback to Improve Working Memory in Schizophrenia

Overview

This study is a confirmatory, double-blind, placebo-controlled randomized clinical trial (RCT) testing whether gamma EEG neurofeedback (EEG-NFB) improves working memory in adults with schizophrenia or schizoaffective disorder. Participants are randomly assigned to receive either active gamma EEG-NFB (real-time feedback of frontal gamma brain activity) or sham EEG-NFB (false pre-recorded feedback), twice weekly for 12 weeks. Working memory (N-back task), brain gamma coherence, and everyday community functioning are assessed at baseline, mid-treatment, end of treatment, and follow-up.

Schizophrenia is associated with deficits in gamma frequency (30-45 Hz) neural synchrony and working memory that are resistant to antipsychotic treatment. EEG neurofeedback (EEG-NFB) targeting frontal gamma coherence is a non-invasive approach that may restore gamma synchrony and improve working memory by reinforcing endogenous neural oscillations in real time. This confirmatory RCT builds on a successful pilot trial (R33) demonstrating feasibility and preliminary efficacy of gamma EEG-NFB in schizophrenia. Participants (N=104) are randomized 1:1 to active gamma EEG-NFB or sham EEG-NFB. Active EEG-NFB delivers real-time feedback of frontal gamma coherence (F3/F4, 30-50 Hz) via a CGX wireless headset. Sham participants undergo identical procedures but receive pre-recorded feedback unrelated to their own brain activity. Both groups complete 30 sessions over 12 weeks (two sessions per week). Co-primary outcomes are working memory (N-back d-prime) and frontal gamma coherence, assessed at baseline and Week 12. Secondary outcomes include global cognition, symptoms (PANSS), negative symptoms (CAINS), and community functioning (ILSS, UPSA-Brief, SFS). Follow-up assessments are conducted at 3 months (Week 24) and 6 months (Week 36) post-treatment. Primary analysis uses mixed model repeated measures (MMRM).