Nocturnal vagus nerve stimulation enhances cognitive functions in patients with early Alzheimer's disease.

BackgroundAuricular transcutaneous vagus nerve stimulation (atVNS) has been proposed as a non-invasive neuromodulation approach for cognitive disorders, including Alzheimer's disease (AD). Sleep represents a physiological state characterized by enhanced vagal activity and memory consolidation, making it a potentially optimal window for stimulation.ObjectiveTo investigate the cognitive effects of nocturnal atVNS in individuals diagnosed with mild cognitive impairment (MCI) and AD.MethodsParticipants underwent nightly atVNS using a Vguard device, specifically designed for non-invasive stimulation during sleep. Cognitive performance was evaluated using four standardized neuropsychological instruments, including the Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-Cog).ResultsRepeated nocturnal atVNS over several months was associated with significant improvements in global cognitive function. Among the administered tests, the ADAS-Cog demonstrated the greatest sensitivity in detecting stimulation-related changes.ConclusionsNocturnal atVNS may constitute a promising therapeutic strategy for enhancing cognition in patients with MCI and AD. By leveraging sleep-related vagal activity, this approach could potentially delay or prevent the progression of MCI to AD and dementia.