The promise of portable remote auditory stimulation tools to enhance slow‐wave sleep and prevent cognitive decline

Abstract

Dementia is the seventh leading cause of mortality, and a major source of disability and dependency in older individuals globally. Cognitive decline (and, to a lesser extent, normal ageing) are associated with sleep fragmentation and loss of slowwave sleep. Evidence suggests a bidirectional causal link between these losses.Phase-locked auditory stimulation has emerged as a promising non-invasive tool to enhance slow-wave sleep, potentially ameliorating cognitive decline. In laboratory settings, auditory stimulation is usually supervised by trained experts. Different algorithms (simple amplitude thresholds, topographic correlation, sine-wave fitting, phase-locked loop, and phase vocoder) are used to precisely target auditory stimulation to a desired phase of the slow wave. While all algorithms work well in younger adults, the altered sleep physiology of older adults and particularly those with neurodegenerative disorders requires a tailored approach that can adapt to older adults' fragmented sleep and reduced amplitudes of slow waves. Moreover, older adults might require a continuous intervention that is not feasible in laboratory settings. Recently, several auditory stimulation-capable portable devices ('Dreem ® ', 'SmartSleep ® ' and 'SleepLoop ® ') have been developed. We discuss these three devices regarding their potential as tools for science, and as clinical remoteintervention tools to combat cognitive decline. Currently, SleepLoop ® shows the most promise for scientific research in older adults due to high transparency and customizability but is not commercially available. Studies evaluating down-stream effects on cognitive abilities, especially in patient populations, are required before a portable auditory stimulation device can be recommended as a clinical preventative remote-intervention tool.

Automated analysis of a large-scale paediatric dataset illustrates the interdependent relationship between epilepsy and sleep

“…In this study, our methodology has been applied to patients with childhood epilepsy, but the proposed methods are applicable to any disorder related to sleep or spike alterations (e.g., Alzheimer’s, Parkinson’s, autism, ADHD). A better understanding of the underlying pathology has become increasingly important in recent years, due to the rise of new technologies enabling us to manipulate sleep, such as acoustic stimulation 50 , which may lead to new treatment options for these disorders.…”

Acoustic stimulation during slow wave sleep shows delayed effects on memory performance in older adults

“…Other studies using multiple nights of PLAS further confirmed a lack of physiological habituation, rendering PLAS a good candidate for long-term applications (Debellemaniere et al, 2018;Lustenberger et al, 2022). With current developments in the field of PLAS-capable home-use devices (Zeller et al, 2023), future research can delve into options for long-term PLAS-applications and investigate whether memory increases can be sustainable.…”

Memory retention following acoustic stimulation in slow-wave sleep: a meta-analytic review of replicability and measurement quality

“…This suggests that phase-locked acoustic stimulation in younger adults could be an effective tool to modulate memory retention. Toward this end, Wunderlin and colleagues compare portable systems that allow for multiple nights of electroencephalogram (EEG) recordings and phase-locked acoustic stimulation delivery with the goal of collecting quality data over multiple nights to strengthen future studies (Zeller et al, 2023). A meta-analysis by Stanyer and colleagues reports a memory performance effect size (d = 0.68, 95% CI [0.06, 1.30]) that is almost three-fold larger than reported for a similar set of studies in the meta-analysis by Wunderlin and colleagues.…”