Motor dyscontrol in narcolepsy: Rapid‐eye‐movement (REM) sleep without atonia and REM sleep behavior disorder

TLDR

Narcolepsy is marked by REM‑sleep abnormalities such as brief REM latency, hypnagogic hallucinations, sleep paralysis, and occasionally sustained muscle tone or excessive twitching during REM. The authors aim to demonstrate that REM sleep behavior disorder can also be a symptom of narcolepsy. They examined 17 narcoleptic patients (ages 8–74) who met established diagnostic criteria for both narcolepsy and REM sleep behavior disorder. Among these patients, 10 displayed overt REM sleep behavior disorder, 7 showed subclinical persistent tone or twitching, 71 % were male, the disorders usually co‑occurred, and in three cases stimulant or tricyclic treatment for cataplexy induced or worsened REM sleep behavior disorder.

Abstract

Narcolepsy involves abnormalities of rapid-eye-movement (REM) sleep, including a short latency to the onset of REM sleep, hypnagogic hallucinations, and sleep paralysis. In addition, persistence of muscle tone by electromyographic criteria or excessive muscle twitching during REM sleep or both have been reported in treated and untreated narcoleptic patients. We report that another previously described abnormality of REM sleep, REM sleep behavior disorder, may also be a symptom of narcolepsy. This disorder was found in 10 narcoleptic patients during routine clinical evaluations involving polysomnography and multiple sleep latency tests. During REM sleep, 7 additional narcoleptic patients displayed persistent muscle tone and/or excessive twitching, which we believe to be subclinical components of REM sleep behavior disorder. These 17 patients, diagnosed by established criteria for narcolepsy and for REM sleep behavior disorder, ranged in age from 8 to 74 years. Seventy-one percent were male. Narcolepsy and REM sleep behavior disorder most commonly emerged in tandem. In 3 patients, treatment of narcolepsy-cataplexy with stimulants and tricyclics either induced or exacerbated REM sleep behavior disorder.