Deep brain stimulation versus nonsurgical treatment for severe Alzheimer's disease: A long-term retrospective cohort study

Severe Alzheimer's disease (AD) is characterized by significant neuropsychiatric symptoms and sleep disorders, with limited effectiveness of conservative drug treatments. Deep brain stimulation (DBS) offers a potential alternative. To evaluate the efficacy, safety, and long-term outcomes of DBS versus conservative treatment in patients with severe AD. We retrospectively analyzed 40 patients with severe AD diagnosed at the People's Liberation Army General Hospital from 2015 to 2022. Twenty patients received DBS, and twenty received conservative treatment. Treatment effects were assessed using standardized scales at three- and twelve-months post-treatment. Primary outcomes included changes in cognitive function [Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Alzheimer's Disease Rating Scale-Cognitive subscale, Clinical Dementia Rating). Secondary outcomes included quality of life, sleep quality, neuropsychiatric symptoms, and caregiver burden (Barthel Index, Functional Activity Questionnaire, Functional Independence Measure (FIM), Neuropsychiatric Inventory (NPI), Hamilton Anxiety Rating Scale (HAM-A), Hamilton Depression Rating Scale (HAM-D), Pittsburgh Sleep Quality Index (PDQI), Zarit Burden Interview (ZBI)]. DBS patients showed significantly greater improvements in MMSE, MoCA, FIM, and ZBI scores than controls, suggesting improved cognitive function and quality of life, and reduced caregiver burden (p < 0.05). Notably, DBS significantly reduced HAM-A, HAM-D, and PSQI scores, and improved NPI scores more than controls, indicating significant amelioration of neuropsychiatric symptoms and sleep disorders (p < 0.05). DBS is a safe and reversible treatment that potentially enhances cognitive function and quality of life in severe AD patients and alleviates caregiver burden. For the first time, we report that DBS also improves neuropsychiatric symptoms and sleep disorders, highlighting its clinical potential in AD.