To characterize sleep disorders in children and adults with different forms of myotonic dystrophy type 1 (DM1) and to evaluate their impact on cognitive functions, excessive daytime sleepiness (EDS), and fatigue. To determine the relationship between EDS,

E. K. Erokhina, E. A. Melnik, D. D. Lebedeva, K. V. Shamtieva, T. V. Peters, E. P. Pavlikova, V. V. Gepard, D. V. Vlodavets 
Neuroscience and Behavioral Physiology, 2024
To characterize sleep disorders in children and adults with different forms of myotonic dystrophy type 1 (DM1) and to evaluate their impact on cognitive functions, excessive daytime sleepiness (EDS), and fatigue. To determine the relationship between EDS, fatigue, and sleep disorders and patients’ quality of life. Materials and methods. The study included 48 adults and nine children with confirmed DM1. Patients underwent assessment of clinical and history data, neurological and cognitive status, extent of EDS and fatigue, and quality of life using international scales and questionnaires. Polysomnography was performed to identify sleep disorders. Results. Obstructive sleep apnea syndrome (OSAS) was found in 78% of children and 79.2% of adults. The severity of OSAS in adults, in contrast to children, was influenced by obesity (p < 0.001) and the extent of muscle weakness (p = 0.033), especially of the neck muscles (p = 0.018). Increases in the duration of stage I sleep (p = 0.008) and the microactivation index (p = 0.005) were detected in patients with OSAS and nocturnal hypoxemia. EDS and fatigue were present in 31 (64.6%) and 34 (70.8%) adults, respectively, and in nine (18.8%) at disease onset. Greater severity of muscle symptoms, anxiety, and depression contributed to increased fatigue in adults and the presence of obesity and type 2 diabetes mellitus contributed to EDS. Increased fatigue had a greater impact on quality of life than EDS and sleep disturbances. Conclusions. OSAS occupies the leading position among the spectrum of sleep disorders in all age groups and its development is facilitated by the presence of muscle weakness and obesity. Cognitive and emotional disturbances do not result from sleep apnea, but rather develop as a result of primary damage to the central nervous system. The presence of increased fatigue reduces patients’ quality of life.