Randomized, sham-controlled, clinical trial of repetitive transcranial magnetic stimulation for patients with Alzheimer’s dementia in Japan

Abstract

BackgroundSeveral medications have been applied to Alzheimer’s dementia patients (AD) but their efficacies have been insufficient. The efficacy and safety of 4 weeks of repetitive transcranial magnetic stimulation (rTMS) in Japanese AD were evaluated in this exploratory clinical trial.MethodsForty-two patients, aged 60–93 years (average, 76.4 years), who were taking medication (> 6 months) and had Mini-Mental State Examination (MMSE) scores ≤ 25 and Clinical Dementia Rating Scale scores (CDR-J) of 1 or 2, were enrolled in this single-center, prospective, randomized, three-arm study [i.e., 120% resting motor threshold (120% RMT), 90% RMT for the bilateral dorsolateral prefrontal cortex, and Sham]. Alzheimer’s Disease Assessment Scale-Japanese Cognitive (ADAS-J cog), Montreal Cognitive Assessment (MoCA-J), Clinical Global Impression of Change (CGIC), Neuropsychiatric inventory (NPI), and EuroQOL 5 Dimensions 5-Level (EQ-5D-5L) were administered. The primary endpoint was the mean change from baseline in the MMSE score (week 4). An active rTMS session involved applying 15 trains bilaterally (40 pulses/train at 10 Hz; intertrain interval, 26 s). Participants received ≥ 8 interventions within the first 2 weeks and at least one intervention weekly in the 3rd and 4th weeks. Full Analysis set (FAS) included 40 patients [120% RMT (n = 15), 90% RMT (n = 13), and Sham (n = 12)].ResultsIn the FAS, MMSE, ADAS-J cog, MoCA-J, CDR-J, CGIC, NPI, and EQ-5D-5L scores between the three groups were not significantly different. Two patients were erroneously switched between the 120% RMT and 90% RMT groups, therefore, “as treated” patients were mainly analyzed. Post hoc analysis revealed significant treatment efficacy in participants with MMSE scores ≥ 15, favoring the 120% RMT group over the Sham group. Responder analysis revealed 41.7% of the 120% RMT group had a ≥ 3-point improvement in the ADAS-J cog versus 0% in the Sham group (Fisher’s exact test, p = 0.045). The MoCA-J showed the same tendency but was not significant. Efficacy disappeared in week 20, based on the ADAS-cog and MoCA-J. No intervention-related serious adverse events occurred.ConclusionThis paper is the first report of using rTMS in Japanese AD patients. The treatment seems safe and moderate-mild stage AD should be target population of pivotal clinical trial with 120% RMT rTMS.