The Clinical and Polysomnography Characteristics Associated with Hypersomnia

Most patients with hypersomnia, defined as total sleep time of at least 19 hours, are mostly young, with younger age at excessive daytime sleepiness (EDS) onset, and have normal sleep architecture and continuity, according to study results published in Sleep.

Previous studies reported that hypersomnolence, defined by EDS or excessive quantity of sleep (EQS), is associated with increased morbidity. The objective of the current study was to explore the clinical and polysomnographic characteristics associated with EQS and EDS during extended polysomnography recording.

This study included 266 participants (201 women; mean age, 26.5 years) who completed polysomnography recording followed by a modified multiple sleep latency test (mMSLT). The mMSLT included 5 nap opportunities every 2 hours, from 9 AM to 5 PM, where participants were awakened following 1 minute of sleep. After that, they all underwent the 32-hour bed-rest polysomnography recording. The mMSLT and 32-hour bed-rest monitoring both included electroencephalogram, electrooculogram and submentalis electromyography.

Study participants were classified into 4 groups: bed-rest total sleep time of less than 19 hours compared with at least 19 hours, and mean sleep latency (MSL) of no more than 8 compared with over 8 minutes. The participants were also categorized into 3 groups: isolated EDS, isolated EQS, or complaint of both EDS and EQS.

Overall, 90.15 percent of participants had complaints of isolated EDS, 79.76 percent had complaints of EQS, and 71.71 percent reported having both conditions.  MSL was no greater than 8 minutes in 132 (49.62%) participants and was between 8 and 10 minutes in 36 (13.53%) participants.

Compared to patients with bed-rest total sleep time less than 19 hours, those with sleep duration of at least 19 hours were younger, had EDS onset at a younger age, higher sleep efficiency on polysomnography performed the night before the bed-rest recording, and shorter MSL on mMSLT.

Compared with participants with MSL greater than 8 minutes on the mMSLT, those with MSL no greater than 8 minutes reported less frequently night-EQS of at least 9 hours and 24-hour-EQS of at least 11 hours on weekdays and weekends, higher sleep efficiency, longer sleep duration, and higher percentage hypersomnia.

A total of 207 patients reported isolated EDS and/or hypersomnia, of which 5 met the diagnostic criteria for narcolepsy type 2. 71 of the remaining 202 participants met the criteria for idiopathic hypersomnia.

Limitations of this study included selection bias, the missing information on participants’ circadian preferences, and the exclusion of participants with severe forms of comorbidities, including BMI, depressive symptoms, and sleep apneas.

“Sleep duration and EDS should be quantified using self-reported and objective measures in a controlled procedure to differentiate long sleepers, patients with hypersomnia and patients with idiopathic hypersomnia,” concluded the study researchers.

Reference

Evangelista E, Rassu AL, Barateau L, et al. Characteristics associated with hypersomnia and excessive daytime sleepiness identified by extended polysomnography recording. Sleep. Published online November 29, 2020. doi:10.1093/sleep/zsaa264