Sensory stimulation improves daily functions in Alzheimer’s disease

• Published in: Alzheimer's & dementia Vol. 18; no. S4
• Main Authors: Cimenser, Aylin, Hempel, Evan, Konisky, Alexandra, Vaughan, Brent, Megerian, Jonathan Thomas, Malchano, Zach, Hajos, Mihaly
• Format: Journal Article
• Language: English
• Published: 01.12.2022
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1002/alz.060270

Background Abnormal neuronal function in Alzheimer’s disease (AD) is characterized by unbalanced neuronal excitatory‐inhibitory tone, distorted neuronal synchrony, and network oscillations, presumably contributing to the pathogenesis of the disease and accelerating disease progression. The probability that abnormal neuronal activity directly contributes to the pathogenesis of the disease has been recently proposed. It has been demonstrated that induction of synchronized gamma oscillation of neuronal networks by sensory stimulation reverses AD‐related pathological markers in transgenic mice carrying AD‐related human pathological genes. The current study evaluated whether non‐invasive sensory stimulation inducing cortical 40 Hz gamma oscillation is clinically beneficial for patients in AD spectrum. Method The data studied here is from Overture clinical trial (NCT03556280). The study included a treatment group, where participants received daily, 1‐hour, 40Hz gamma visual and auditory stimulation for 6‐months at home, and a placebo group. To assess the treatment efficacy on daily functional abilities, the Alzheimer’s Disease Cooperative Study ‐ Activities of Daily Living (ADCS‐ADL) scale was used. Assessments were made at baseline and every four weeks throughout the study. ADCS‐ADL consists of 23‐items where each item aims to assess different functional abilities. The change in ADCS‐ADL as well as change in each individual item’s score between the treatment group (n = 33) and the placebo group (n‐ = 19) were compared using a mixed model for repeated measures (MMRM). Result We observed that treatment group participants were able to maintain their functional abilities while placebo group participants showed a decline as assessed by ADCS‐ADL, p<0.001. Within the instrumental ADCS‐ADL individual items, the most significant differences between the two groups, all favoring treatment group, were observed in: (1) Attentive participation in conversations, p<0.001, and (2) Finding personal belongings, p<0.043. Conclusion Our results suggest that daily, 1‐hour 40Hz gamma sensory stimulation may help prevent functional decline in patients with AD spectrum disorder. Preventing functional loss would help both patients and caregivers. Furthermore, it may reduce the need for institutionalization and reduce healthcare costs. Larger studies are planned to confirm these initial findings on the benefits of gamma sensory stimulation on function.