Assessing the feasibility of reducing slow-wave activity with a wearable device in a home setting

Abstract

Objective: Sleep deprivation has been shown to reverse depressive symptoms in approximately 60% of patients with major depression. Its therapeutic utility, however, is hampered by the typical relapse into the depressive state after recovery sleep and the detrimental physiological and psychological effects of prolonged wakefulness. This pilot aims to assess the feasibility of reducing slow-wave activity (SWA) by performing auditory stimulation using a wearable device (MHSL-Sleepband v3) in a home setting. Methods: We recorded frontal EEG in five healthy participants (24.3±2.3 years old) for six consecutive nights with tone application (verum) and six nights without (sham). The device precisely delivered tones upon detecting the slow-wave down-phase (before the negative peak) and N2/N3 sleep, using alternating 10-s ON-OFF window pairs. Device usability was assessed on a scale from 0, not at all difficult, to 5, very difficult. Sleep scoring (30 s epochs) was performed according to AASM guidelines. Separately considering ON and OFF windows, we used linear mixed effects models to analyze potential differences in SWA (0.5-4.0 Hz) between verum and sham stimulation nights. Results: All five participants used the wearable device for twelve nights. The device was considered easy to use (all participants scored < 2). Due to artefacts (signal loss of > 20%), four nights of one participant were excluded from analysis. Fifty-six nights were included in the analysis (n = 27 sham, n = 29 verum). We saw an effect of tone application, with SWA in OFF windows being lower on verum nights (166 μV2, 95%-CI from 68 to 266, p < .01) and unchanged in ON windows (p = 0.99) as compared to sham nights. When averaging SWA from ON and OFF windows we found no difference between verum and sham (p = 0.21). Sleep architecture (stage percentage) did not change due to conditions or nights (p > 0.05 for all stages). Conclusions: This proof-of-concept study in healthy volunteers suggests that down-phase sleep modulation with the MHSL-Sleepband v3 is feasible and reduces SWA in N2/N3 sleep. Future clinical trials are planned to evaluate the efficacy of lowering SWA without disrupting the overall sleep architecture in depressed patients.