Concurrent virtual reality and transcranial alternating current stimulation for social cognition and neural activity in schizophrenia: A proof-of-concept study

Social cognition, including theory of mind (ToM), is impaired in people with schizophrenia which can significantly impact daily functioning. Current interventions for social cognitive impairment are often time consuming and have limited ecological validity. Combining emerging technologies such as virtual reality (VR) and transcranial alternating current stimulation (tACS) may help address these limitations. The current study applied theta tACS to the right temporoparietal junction (rTPJ) during VR social cognition training in 15 participants with schizophrenia. Neurophysiological (event-related potentials and spectral power) and behavioural outcome measures (ToM task performance) were assessed. Participants underwent two experimental sessions. One session involved VR with concurrent active theta tACS (5Hz frequency) and the other consisted of VR with concurrent sham theta tACS. Resting state electroencephalography (EEG) and ToM tasks with concurrent EEG were measured pre- and post- VR-tACS. Order of stimulation condition was randomised, and stimulation and assessments were all double-blinded. We found ToM task response time improved after VR, regardless of tACS condition. While only VR and active tACS, but not sham, resulted in a widespread increase in resting state theta power. This is the first study to combine VR and tACS in a psychiatric population to address social cognition and provides initial evidence to support the feasibility and efficacy of a combined VR-tACS protocol in schizophrenia. Implications for future research are discussed.