Diffuse esophageal spasm is a disease of unknown etiology in which neural or muscular control mechanisms malfunction, resulting in impaired and sometimes painful swallowing response, and inappropriate muscular contraction. An association between social stresses and disease activity suggesting elements of central control has been observed. In an effort to uncouple conscious central mechanisms from end organ response, we manometrically studied esophageal activity of four patients with symptomatic diffuse esophageal spasm while asleep (identified by electroencephalographic monitoring) as compared to wakeful states. We observed significant decreases from awake studies in number and duration of spontaneous contraction, during all sleep stages. We conclude that CNS mechanisms participate in the expression of the abnormal excitability of the esophagus in symptomatic diffuse esophageal spasm.