Daytime somnolence in myotonic dystrophy

Abstract

Somnolence in myotonic dystrophy (DM) has not been measured using a reliable daytime somnolence scale. The aim of this study was to compare somnolence in DM patients with healthy controls and Charcot-Marie-Tooth disease (CMT) patients using such a scale and to compare this with potential contributory factors. We investigated 35 subjects with adult-onset DM, 16 healthy controls and 13 CMT controls. The Epworth Sleepiness Scale (ESS) was the principal measurement of daytime somnolence. Nocturnal sleep was assessed using a sleep diary. Other assessments measured daytime respiratory function, cognitive function, motor impairment, disability, swallowing capacity and depression. DM and CMT patients had greater daytime sleepiness than unaffected controls. In the DM group significant correlations were found between somnolence and measures of disability, sleep quality and some measures of depression. It was concluded that there is an abnormal level of daytime somnolence in DM, which is partially associated with disability.

Sleep apnea in adult myotonic dystrophy patients who have no excessive daytime sleepiness

“…Among these symptoms, EDS, which is a very characteristic symptom of sleep apnea, is very common in MD [13][14][15][16][17][18]. Guilleminault et al found a correlation in MD patients between EDS and apnea index [3].…”

“…Therefore, PSG should always be considered in the presence of this symptom. EDS is common also in patients with MD [13][14][15][16][17][18]. Published sleep studies in MD patients with EDS have reported that sleep apnea is the most common cause of this symptom in MD [15,16,19,20].…”

Cerebral involvement in myotonic dystrophies

“…Excessive daytime sleepiness is a prominent complaint made by partners and relatives of patients with DM1, 55,90,102 but the patients seem to minimize the problem for unclear reasons that may relate to their global cognitive and behavioral profile. This attitude may explain why the Epworth Sleep Scale often underestimates excessive daytime sleepiness in patients with DM1.…”

“…27,41 Adult-Onset DM1. More than 50% of patients with classic DM1 are referred because of excessive daytime sleepiness 55,90,102 or fatigue. 49 Patients usually minimize their symptoms, do not keep outpatient appointments, and seem unconcerned about their health.…”

Neuromuscular disorders and sleep

“…The second group of myotonic disorders consists of the dominantly inherited multisystem myotonic dystrophies [2•,31,32]. Myotonic dystrophy type 1 (Steinert's disease) is the most common muscular dystrophy of adult life characterized by myotonia, endocrine dysfunctions, cataract formation, cardiac conduction defect, and muscle weakness [33,34]. Hypersomnolence, hypercapnia, SDB, and nocturnal desaturation are common in myotonic dystrophy.…”