Amyotrophic lateral sclerosis associated with insomnia and the aggravationof sleep-disordered breathing

A case of amyotrophic lateral sclerosis (ALS) diagnosed by sleep-disordered breathing is described. The patient's chief complaints were insomnia and n octurnal dyspnea after taking a hypnotic drug. On examination, he showed re strictive ventilatory impairment, alveolar hypoventilation and hypoxia. Pol ysomnographic examination revealed marked hypoxia during REM sleep periods, decreased duration of REM sleep periods, and increased sleep disruption. A myotrophic lateral sclerosis was diagnosed by the neurological finding of p araspinal muscle weakness and neurogenic changes revealed by needle electro myography and muscle biopsy The daytime and nocturnal respiratory insuffici ency improved after nasal bilevel positive airway pressure therapy. Amyotro phic lateral sclerosis should be suspected as a cause of insomnia and noctu rnal dyspnea.