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.