AT A workshop held in Minneapolis, Minn, in 1995, Professor Peter S. Harper pointed out that daytime sleepiness may be the most common complaint of patients with myotonic dystrophy (hereafter "DM" for "dystrophia myotonica"). Most spouses of patients with DM would testify that their loved ones amaze them by falling asleep whenever and wherever they can. Patients with DM may also have sleep apnea. These abnormalities have been at least partly attributed to impaired central nervous system functions. Additionally, psychological literature supports the existence of personality disorders and impaired intellectual, cognitive, and frontal "executive" functions in patients with DM. As neurologists, we are familiar with "indifferent" attitudes of these patients toward the disease even when they have relatively severe manifestations. In affected children, the central nervous system manifestations may be much more conspicuous than those seen in adults. In the congenital form of DM (CDM), mental retardation becomes the major element of disability after the child survives the life-threatening neonatal hypotonia. These clinical findings attributable to brain dysfunctions were well summarized by Harper1 and have been confirmed and extended by more recent studies.
Ashizawa T. Myotonic Dystrophy as a Brain Disorder. Arch Neurol. 1998;55(3):291-293. doi:10.1001/archneur.55.3.291