Long-term effects of multisession gamma transcranial alternating current stimulation in Alzheimer's disease

This study investigated the long-term clinical effects of multisession gamma transcranial alternating current stimulation (tACS) over the precuneus in early-stage Alzheimer's disease. Forty-six patients from a previous randomized, double-blind, sham-controlled trial with an open-label extension underwent follow-up at 36 and 72 weeks. Participants received either 8 or 16 weeks of gamma tACS. Both treatment durations showed comparable long-term outcomes. Alzheimer's Disease Assessment Scale–Cognitive Subscale did not significantly worsen at 36 weeks, and Face–Name Association Test remained stable at both follow-up time points, whereas Clinical Dementia Rating–Sum of Boxes and Alzheimer's Disease Cooperative Study–Activities of Daily Living worsened over time. These findings suggest relative preservation of selected cognitive measures, despite worsening in broader clinical and functional outcomes.