Magnetic seizure therapy preserves delayed memory and 40-Hz auditory steady-state responses compared with electroconvulsive therapy in schizophrenia.

BACKGROUND Electroconvulsive therapy (ECT) is effective for schizophrenia but often impairs delayed memory, whereas magnetic seizure therapy (MST) typically spares cognition. We investigated whether these modalities differentially affect 40-Hz auditory steady-state responses (ASSR)-a marker of gamma synchrony critical for memory-and if these changes predict cognitive outcomes.

METHODS This study is a secondary analysis of a randomized clinical trial for schizophrenia comparing ECT (n = 16) and MST (n = 17). Clinical symptoms and cognition were assessed using Positive and Negative Syndrome Scale (PANSS) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) at baseline and after 10 treatment sessions. 40-Hz ASSR were recorded via EEG at baseline and after the first treatment session.

RESULTS Both treatments improved psychotic symptoms. However, ECT induced cognitive deficits (particularly delayed memory) and significant reductions in acute ASSR power and phase-locking. In contrast, MST preserved both cognitive function and ASSR integrity. Notably, within the ECT group, greater acute suppression of ASSR power predicted better preservation of delayed memory.

CONCLUSION MST demonstrates a superior safety profile compared to ECT, preserving both gamma synchrony and memory. The association between acute gamma suppression and better memory retention in ECT suggests this reduction may be an adaptive physiological response. Thus, early ASSR changes may serve as a predictive biomarker for cognitive tolerability.