SLEEP-RELATED RESPIRATORY DISTURBANCES IN PATIENTS WITH DUCHENNE MUSCULAR-DYSTROPHY

Sleep-related respiratory disturbances (SRD) in patients with muscle diseases may have significant clinical implications, because the patients frequently die at night. The aims of the study were to : 1) assess the presence and severity of sleep-related respiratory disturbances in patients with Duchenne muscular distrophy (DMD); and 2) investigate the relationship of sleep-related respiratory disturbances to daytime symptoms and pulmonary function. We studied six clinically stable patients with Duchenne muscular dystrophy, mean age (+/-SD) 18+/-2 yrs. Vital capacity was 27+/-19% of predicted and daytime arterial oxygen tension (Pao(2) was 10.9+/-1 kPa (range 8.9-12.4 kPa). The presence of daytime somnolence, insomnia, headache, nightmares and/or snoring was recorded. Four patients (67%) showed symptoms that suggest sleep-related respiratory disturbances. At night, the apnoea-hypopnoea index (AHI) was 11+/-6. The patients with more symptoms during the daytime had the highest AHI scores. Most of the apnoeas (85%) were central, particularly during rapid eye movement (REM) sleep. Sleep architecture was well-preserved. Arterial desaturation (>5% below baseline) occurred during 25+/-23% of total time. AHI correlated with daytime Pao(2), and AHI in REM sleep correlated with age. A stepwise multivariate analysis showed that Pao(2) and, to some extent, the degree of airflow obstruction were significantly correlated with AHI. We conclude that sleep-related respiratory disturbances are frequently present in patients with Duchenne muscular dystrophy. Therefore, physicians should look for symptoms related to sleep-related respiratory disturbances in these patients, Furthermore, sleep-related respiratory disturbances should be strongly suspected in older Duchenne muscular dystrophy patients, particularly if diurnal arterial hypoxaemia is concurrently present.