[Sleep disorders and fatigue in patients with different forms of myotonic dystrophy type 1]

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

The study included 48 adults and 9 children with confirmed DM1. Patients underwent an assessment of clinical and anamnestic data, neurological, cognitive status, severity of EDS, fatigue, quality of life according to international scales and questionnaires. Polysomnography was performed to identify sleep disorders.

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), the severity of muscle weakness (p=0.033), especially the neck muscles (p=0.018). In patients with OSAS and nocturnal hypoxemia, an increase in the duration of the 1st stage of sleep (p=0.008) and in the microactivation index (p=0.005) was revealed. EDS and fatigue were present in 31 (64.6%) and 34 (70.8%) adults, respectively, in 9 (18.8%) they emerged at the onset of the disease. The greater severity of muscle symptoms, anxiety, depression contributed to increased fatigue in adults and the presence of obesity and type 2 diabetes mellitus contributed to EDS. Increased fatigue affects the quality of life to a greater extent than EDS and sleep disturbances.

OSAS, the development of which is facilitated by the presence of muscle weakness and obesity, is the leading syndrome among the spectrum of sleep disorders in all age groups. Cognitive and emotional impairments are not the result of sleep apnea, but rather develop because of a primary CNS lesion. The presence of increased fatigue reduced the quality of life of patients.