Multiple Sclerosis & Sleep Disorders: Exploration of Sleep Disordered Breathing –Apnea Hypopnea Index Non-REM Vs REM in Multiple Sclerosis

Background:  Fatigue is a common and often disabling symptom reported in patients with MS. Fatigue as a symptom likely reflects the culmination of a complex heterogeneous problem reported as a simple complaint. Improved understanding of some pathogenic aspects contributing to fatigue might lead to improved treatment efficacy and satisfaction.  SDB is a common cause of daytime fatigue and impaired quality of life.  Characterization of the types and degrees of SDB in patients with MS has not well explored in a large cohort. Analysis underlying sleep architecture disturbances and SDB in Non-REM and REM sleep in this population is very limited.

Objectives:  To explore the correlation of polysomnography (PSG) documented first night sleep abnormalities related to both sleep disordered breathing (SDB) and contrast the differences of SDB in Non-REM and REM sleep in a large cohort of patients with multiple sclerosis (MS) who report fatigue. 

Methods: Retrospective analysis of patients with MS who reported fatigue, and who underwent overnight PSG studies. 

Results: 206 patients with MS who reported fatigue underwent overnight polysomnography.  Of these patients: 64/206 (31%) had no significant SDB (AHI<4.9), 79/ 206 (38%) exhibited mild SDB (5<AHI<19.9), 39/206 (19%) moderate SDB (20<AHI < 39.9), and 24/206 (12%) had severe SDB (AHI>40). PSG analysis of SDB during Non-REM sleep revealed: 81/205 (40%) no SDB (AHI<4.9), 70/205 (34%) mild SDB (5<AHI<19.9), 36/205 (18%) moderate SDB (20<AHI<39.9), 18/205 (9%) severe SDB (AHI > 40).  In contrast PSG analysis of SDB during REM sleep of those patients who reached REM sleep (12% did not achieve REM Sleep) demonstrated: 61/181 (34%) no SDB (AHI<4.9), 50/181 (28%) mild SDB (5<AHI<19.9), 38/181 (21%) moderate SDB (20<AHI<39.9), whereas 32/181 (18%) had severe SDB (AHI>40).

Conclusions: Fatigue is common in patients with MS.  Sleep disorders are common in patients with MS who report fatigue. SDB during REM sleep may be common and more severe than Non-REM SDB in patients with MS who report fatigue.  Awareness of the differences in degree of SDB of Non-REM and REM associated sleep disordered breathing might impact the consequence of this problem and reinforce the need for treatment even if the % REM sleep is limited during the sleep study.