Phasic tongue movements in human rapid eye-movement sleep.

Polygraphic recordings demonstrated complex tongue movements as unusual phasic phenomena during rapid-eye-movement (REM) sleep in patients with narcolepsy, sleep apnea syndrome, or posterior fossa lesions, and in normal controls. These tongue movements may counteract posterior displacement of the tongue to prevent obstructive sleep apnea, which may otherwise occur in REM sleep because of genioglossal hypotonia. Hypotonia affected not only the genioglossus but also other muscles innervated by pontomedullary neurons during non-REM-sleep-related apnea in patients with sleep apnea syndrome.