Sleep quality and sleep-related symptoms in Pompe disease

Abstract

Late-onset Pompe disease (LOPD) is highly representative for neuromuscular disorders with progressive respiratory muscle dysfunction. Non-invasive ventilation almost inevitably becomes necessary in the majority of patients, and pulmonary complications of diaphragmatic weakness are the major cause of early death in patients with LOPD. Nocturnal hypercapnia is the first sign of respiratory muscle weakness, causing sleep disruption and non-restorative sleep. We investigated sleep-related symptoms along with motor performance, respiratory symptoms, and forced vital capacity (FVC) in 60 adult patients with LOPD. Patients answered the Fatigue Severity Scale (FSS), the Epworth Sleepiness Scale (ESS), the Pittsburgh Sleep Quality Index (PSQI), the Rotterdam 9-Item Handicap Scale (RHS), the SF-36 quality of life (QoL) questionnaire, and a questionnaire covering symptoms potentially indicative of respiratory muscle weakness. All patients performed the 6-min walk test (6-MWT), and FVC (upright and supine) was routinely measured. LOPD was confirmed bioptically or genetically in all patients (30 female, 48.0 ± 14.4 years). 55 patients received enzyme replacement therapy, and 31 individuals were on home ventilatory support. Excessive daytime sleepiness (EDS), sleep disturbances, and fatigue were highly prevalent (ESS > 10: 21.3%, PSQI > 5: 41.0%, FSS > 4: 68.9%). Severity of respiratory distress was significantly correlated with the ESS, FSS and PSQI scores. Fatigue was associated with reduction of supine FVC and walking distance in the 6-MWT. QoL was reduced in the physical domains, and was inversely correlated with fatigue, reduced sleep quality, disease duration, and FVC. In LOPD, EDS, fatigue and sleep disturbances are very common. They show association with symptoms of respiratory muscle weakness and may incidate sleep-disordered breathing. The authors are grateful to all patients who took part in this study.