Gamma sensory stimulation in mild Alzheimer's dementia: An open-label extension study.
Level 4 - case-series / case-control
Open-label extension pilot study (n=5) with external/historical matched cohort controls
PubMed 41137616 · doi:10.1002/alz.70792
What was done
Five patients with mild Alzheimer's disease (AD) received 1 hour of daily 40 Hz audiovisual sensory stimulation over a 2-year open-label extension period. Investigators evaluated 40 Hz neural entrainment via EEG, brain volume via MRI, activity patterns via actigraphy, cognition via neuropsychological testing (MMSE, CDR, FAS), and plasma pTau217 via S-PLEX assay. Cognitive trajectories were compared against matched observational cohorts from NACC, ADNI, and LEADS databases.
What was found
No adverse events occurred during the 2-year intervention. Three female patients with late-onset AD (LOAD) maintained strong EEG entrainment and exhibited less cognitive and functional decline (MMSE, CDR, FAS) relative to matched external controls. Plasma pTau217 was available and measured in only 2 of the 5 participants (both with LOAD), decreasing by 47% and 19% over the 2-year study period.
Why it matters
This study provides initial 2-year feasibility and safety data for non-invasive 40 Hz sensory stimulation in mild AD, offering preliminary pilot evidence linking the intervention to reduced plasma pTau217 in two patients.
Limits
The sample size is extremely small (n = 5 total; biomarker data from only 2 patients). The lack of an internal randomized sham control group requires reliance on external historical cohorts, creating high risk for selection bias and confounding.
Cited by
- supports Exposure to 40 Hz sensory stimulation increases gamma brain wave activity and is associated in early clinical research with a slower rate of cognitive decline.