Methodological approach to sleep state misperception in insomnia disorder: comparison between multiple nights of actigraphy recordings and a single night of polysomnography recording

ABSTRACT Rationale Sleep state misperception (SSM) represents the discrepancy between objectively recorded and subjectively perceived measures of sleep, including sleep onset latency (SOL), sleep duration (TST) and wake duration (WASO). The severity of SSM is higher in insomnia disorder (INS) compared to other populations. SSM is typically assessed in-lab during one night with polysomnographic (PSG) recording or at-home with actigraphy recordings over multiple days, both complemented by subjective sleep reports. Both methods of data collection have their specific strengths and weaknesses, and provide sleep measures that may differ, especially in individuals with sleep disorders. The extent to which the methods and environment of data collection impact measures of sleep misperception remains unclear. This study aimed at providing a comprehensive assessment of SSM in INS and good sleepers (GS) by comparing recordings performed for one night in-lab (PSG and night review) and during several nights at-home (actigraphy and sleep diaries). Methods Fifty-seven INS and 29 GS wore an actigraphy device and filled a sleep diary for two weeks at-home. They subsequently completed a PSG recording and filled a night review the next morning in-lab. Sleep perception index (subjective/objective × 100; in %) of SOL, WASO and TST were computed and compared between methods and groups. Results We found that GS and INS exhibit opposite patterns of sleep misperception. GS displayed a tendency to overestimate TST and WASO but correctly perceived SOL. The degree of misperception was similar across methods within the GS group. In contrast, INS underestimated their TST and overestimated their SOL both in-lab and at-home, yet the severity of misperception (i.e., degree of mismatch) of SOL was larger at-home than in-lab. Finally, INS overestimated WASO only in-lab while correctly perceiving it at-home. While only the degree of TST misperception was stable across methods in INS, misperception of SOL and WASO were dependent on the method used. Conclusions We found that GS and INS exhibit opposite patterns and severity of sleep misperception. While the degree of misperception in GS was similar across methods, we found that only sleep duration misperception was reliably detected by both in-lab and at-home methods in INS. Our results highlight that, when assessing sleep misperception in individuals with insomnia disorder, the method of data collection should be carefully considered in relation to the main sleep outcomes of interest.