%0 Journal Article
%T Sleep-Wake Cycle and Daytime Sleepiness in the Myotonic Dystrophies
%A A. Romigi
%A M. Albanese
%A C. Liguori
%A F. Placidi
%A M. G. Marciani
%A R. Massa
%J Journal of Neurodegenerative Diseases
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/692026
%X Myotonic dystrophy is the most common type of muscular dystrophy in adults and is characterized by progressive myopathy, myotonia, and multiorgan involvement. Two genetically distinct entities have been identified, myotonic dystrophy type 1 (DM1 or Steinert¡¯s Disease) and myotonic dystrophy type 2 (DM2). Myotonic dystrophies are strongly associated with sleep dysfunction. Sleep disturbances in DM1 are common and include sleep-disordered breathing (SDB), periodic limb movements (PLMS), central hypersomnia, and REM sleep dysregulation (high REM density and narcoleptic-like phenotype). Interestingly, drowsiness in DM1 seems to be due to a central dysfunction of sleep-wake regulation more than SDB. To date, little is known regarding the occurrence of sleep disorders in DM2. SDB (obstructive and central apnoea), REM sleep without atonia, and restless legs syndrome have been described. Further polysomnographic, controlled studies are strongly needed, particularly in DM2, in order to clarify the role of sleep disorders in the myotonic dystrophies. 1. Introduction Myotonic dystrophies are autosomal, dominantly inherited, progressive, and multisystemic disorders characterized by neuromuscular weakness, myotonia, early-onset cataracts, endocrine abnormalities, and involvement of other organs including CNS, heart, and gastrointestinal system [1, 2]. There are 2 clinically, histopathologically, and genetically distinct forms of myotonic dystrophy: type1 (DM1) and type2 (DM2), although a high degree of clinical overlap exists between these two entities [3, 4]. DM1 is the most common form of muscular dystrophy in adults, with a prevalence ranging from 5 to 12 per 100000 population among Caucasians. Based on age at onset and severity of symptoms, 4 clinical types of DM1 can be distinguished: mild, adult-onset, early childhood, and congenital onset. The phenotype and genetics of DM2 have been described more recently, and its prevalence has not yet been clearly established. Sleep disturbances are well described in neuromuscular diseases. The presence of sleep dysfunction is also a major cause of morbidity and mortality in patients with neuromuscular disorders. Persistent nocturnal hypoxemia, the end result of sleep disordered breathing (SDB) from any cause, results in cardiovascular and pulmonary failure; in addition, sleep fragmentation and excessive daytime sleepiness lead to disability and may affect mood and cognition. DM1 represents the neuromuscular disorder with the most prominent propensity to sleep disorders and excessive daytime sleepiness [5]. SDB, resulting
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