Sleep stage sequence analysis of sleep onset REM periods in the hypersomnias
- Panagis Drakatos1,
- Angula Suri1,
- Sean E Higgins1,
- Irshaad O Ebrahim1,
- Rexford T Muza1,
- Christopher A Kosky1,
- Adrian J Williams1,
- Guy D Leschziner1,2,3
- 1Sleep Disorders Centre, Guy's and St Thomas’ Hospital NHS Foundation Trust, London, UK
- 2Department of Neurology, Guy's and St Thomas’ Hospitals NHS Foundation Trust, London, UK
- 3Deptartment of Clinical Neuroscience, Institute of Psychiatry, King's College London, UK
- Correspondence to Dr G D Leschziner, Department of Neurology, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK;
- Received 3 July 2012
- Revised 10 September 2012
- Accepted 19 September 2012
- Published Online First 20 October 2012
Background The Multiple Sleep Latency Test (MSLT) remains an important diagnostic tool in the diagnosis of hypersomnias. However, a positive MSLT may be found in other sleep disorders, such as behaviourally induced inadequate sleep syndrome (BIISS). It has been demonstrated that in sleep onset rapid eye movement (SOREM) periods in BIISS, REM sleep tends to arise from stage 2 sleep (non-REM (NREM) 2), rather than stage 1 sleep (NREM1), as in narcolepsy.
Methods We performed sleep stage sequence analysis on 127 patients with nocturnal polysomnography and MSLT, including 25 with narcolepsy with cataplexy (N+C), 41 with narcolepsy without cataplexy (N−C), 21 with idiopathic hypersomnia with long sleep time (IHL), 20 with BIISS and 20 with periodic limb movement disorder (PLMD). 537 naps were recorded, containing 176 SOREM periods.
Results All SOREM periods in the IHL, BIISS and PLMD groups arose from NREM2 sleep, 75% of those in N+C arose from NREM1 and in N−C only 52% arose from NREM1. Within the N−C group, those with SOREM periods all arising from stage 1 had a shorter MSL (p=0.02).
Conclusions These results suggest that SOREM periods arising from NREM1 have high sensitivity for the diagnosis of narcolepsy and that SOREM periods from NREM1 are a marker of severity, either of sleepiness or REM instability. Sleep stage sequence analysis of SOREM periods may also aid more accurate phenotyping of the hypersomnias and in particular clarify heterogeneity among patients with narcolepsy without cataplexy.