1000 Hypnagogic hallucinations as a manifestation of Parkinson’s disease

Hypnagogic hallucinations—vivid, dream-like experiences that occur while falling asleep—can be a symptom of Parkinson's disease (PD) even in patients who do not have narcolepsy. A 66-year-old woman with tremor and dream enactment reported seeing a grim reaper and a dark figure upon falling asleep. She was diagnosed with mild obstructive sleep apnea and loss of REM atonia. Treatment with melatonin and clonazepam improved dream enactment. Over two years, she was diagnosed with PD and started on carbidopa-levodopa; higher doses of dopaminergic therapy were associated with more frequent hypnagogic hallucinations. The case illustrates that such hallucinations are not exclusive to narcolepsy and may be underrecognized in PD.

Study at a glance

Abstract

Abstract Introduction Narcolepsy and Parkinson’s disease (PD) share many similar symptoms. Narcolepsy is characterized by excessive daytime sleepiness, sleep attacks, sleep paralysis, and hallucinations, with or without cataplexy. Hypnagogic hallucinations occur while falling asleep and the person experiencing them typically knows they are not real. Here, we present a case of hypnagogic hallucinations as a manifestation of PD in a patient without narcolepsy. Report of case(s) A 66-year-old female with a history of tremor was seen in the sleep disorders clinic with chief complaints of dream enactment and excessive daytime sleepiness. She described bruising after falling out of bed. On further questioning, she reported instances of seeing “death and a grim reaper as well as a dark figure”, usually upon falling asleep at night. She denied daytime hallucinations. She underwent diagnostic polysomnography (PSG), which showed mild obstructive sleep apnea and loss of rapid eye movement (REM) atonia during brief periods of REM sleep. Treatment for dream enactment was implemented by increasing her dose of melatonin (which she had been taking for insomnia) and initiation of clonazepam, which led to significant improvement in dream enactment. Over the next two years, she was diagnosed with PD and started on carbidopa-levodopa. She reported more frequent hypnagogic hallucinations during a follow-up visit, occurring 1-2 times weekly, which her neurologist attributed to being on higher dosages of dopaminergic therapy. During a recent visit, she reported no dream enactment and infrequent hypnagogic hallucinations. Conclusion Sleep disturbances in PD are common and include insomnia, hypersomnia, and REM behavioral disorder (RBD). A lesser appreciated association is that between hypnagogic hallucinations and PD, as depicted in this case. Partial hypocretin cell loss in PD has been postulated to result in disturbed hypocretin signaling, which probably explains the occurrence of narcolepsy-like symptoms (including hypnagogic hallucinations) in PD. Hypnagogic hallucinations are more common among patients with PD compared to the general population and tend to occur more as PD progresses, with longer duration of treatment with dopaminergic agents, with older age, and in patients with RBD. This case serves as an important reminder that hypnagogic hallucinations are not pathognomonic for narcolepsy and are likely underappreciated in PD. Support (if any)