The effects of non-pharmacological interventions on sleep disturbances in people with subjective cognitive decline: A systematic review

Background Fifty to eighty percent of people aged over 60 have subjective cognitive decline, and more than half report sleep disturbances, which may accelerate their cognitive decline. Non-pharmacological interventions have been identified as the first-line treatment to improve sleep disturbances for people of any age. However, the effectiveness of non-pharmacological interventions among people with subjective cognitive decline varies, and there is a lack of systematic reviews synthesizing their effectiveness in improving sleep disturbances in this population. Objective This study aimed to identify, appraise, and synthesize the effects of non-pharmacological interventions for improving sleep disturbance among people with subjective cognitive decline. Methods Six databases (Medline, Web of Science, Scopus, PsycINFO, EMBASE, CINAHL) and relevant references of included studies were systematically searched. Two researchers screened the literature, extracted data, and independently assessed the quality of the studies. Version 2 of the Cochrane collaboration risk of bias tools for randomized controlled trials was used to assess the quality of studies. Results Seven studies were included in this review. Two studies reported small positive effect sizes for music and meditation interventions based on pre-post within-group comparisons. Another study combined the results of meditation and music and compared them with the usual care group, which reported no improvement in sleep disturbance. A fourth study reported a small positive effect of a brain photobiomodulation intervention, while a fifth reported that mobile-based multidomain interventions did not improve sleep disturbance. Finally, two studies reported acupuncture with medium to large positive effect sizes on improving sleep disturbance. Caution is necessary in interpreting the results, as all studies had methodological limitations and insufficient sample sizes. Conclusion A small number of studies with small sample sizes and methodological limitations support the limited effectiveness of non-pharmacological interventions to improve sleep disturbance in people self-reporting cognitive decline. More rigorous studies are needed to better characterize the impact of non-pharmacological interventions in this population.