Howl

Abstract

Objective

Nightmare disorder consists of the appearance of unpleasant and vivid, repeated dreams, with a situation of discomfort and anguish on awakening. Its prevalence is 3%–4% in adults. They do not associate muscle mobilization during this phase. REM sleep behavior disorder (RSBD) is a rare parasomnia (0.5% of people older than 60 years of age), characterized by the presence of unpleasant dreams, with violent content, and vigorous movements of limbs (kicks and punches), reflecting a loss of muscle atony typical of the REM phase of sleep. Language (screams and words) can also be emitted. The same clinical manifestations of RSBD can appear in other sleep disorders. The diagnosis requires the performance of a polysomnography.

Methods

We present the case of a 41-year-old man referred for vivid and unpleasant dreams, beginning in the last year, related to work stress.

Results

The polysomnography showed the loss of atony in the REM phase and emission of a prolonged howl after which the patient continues in the REM phase.

Discussion

Prolonged howling is a very rare symptom in sleep disorders, and very atypical in RSBD, so polysomnography is essential to confirm the diagnosis and rule out other parasomnias.

PRACTICAL IMPLICATIONS

Isolated RSBD heralds a neurodegenerative condition (usually a synucleinopathy) in more than 90% of patients up to 10–14 years later. Its recognition is crucial for prognostic implications.

REM behavior disorder is more frequent from the sixth decade, so it is easier to underdiagnose the cases of young patients and confuse it with nightmares.

Nightmare disorder consists of the appearance of unpleasant and vivid, repeated dreams, with a situation of discomfort and anguish on awakening, which are remembered, and are usually triggered by a stressful situation. Its prevalence is 3%–4% in adults. They do not associate muscle mobilization during this phase, do not precede any neurodegenerative disease, and have a good prognosis, without the need for overnight polysomnography for diagnosis.^1-3

REM sleep behavior disorder (RSBD) is a rare parasomnia (0.5% of people older than 60 years of age) and is characterized by the presence of unpleasant dreams, with violent content, and vigorous movements of limbs (kicks and punches) as a representation of those dreams, reflecting a loss of muscle atony typical of the REM phase of sleep.^4,5 Language (screams and words) can also be emitted. It precedes (up to 14 years) a neurodegenerative disease in 91% of cases, normally associated with the deposit of alpha-synuclein protein.

The same clinical manifestations of RSBD can appear in other sleep disorders such as somniloquy, somnambulism, or nightmares. Unpleasant dreams can occur in any phase of sleep. The diagnosis requires in all cases the performance of a polysomnography that shows the presence of muscle atony in the REM phase (to differentiate from other disorders of other phases such as sleepwalking in phase 3 NREM or the absence of loss of muscle atony in the REM stage nightmares).

We present the case of a 41-year-old man, without previous pathologies, referred for vivid and unpleasant dreams, beginning in the last year, related to work stress. It has not improved with anxiolytic treatment, and it associates sporadic nonviolent movements of the extremities. The neurologic examination revealed no tremor, rigidity, cerebellar or gait disturbances, or alterations in the neuropsychological tests. A magnetic resonance of the brain was performed with no abnormalities, general laboratory tests with no abnormalities including liver enzymes, iron and thyroid hormones, and an overnight polysomnography (PSG) was requested (Video 1).

Video 1

Nocturnal polysomnography in REM stage. Nocturnal polysomnography (REM phase stage): the emission of a prolonged howl is heard, in addition to muscular activity in the chin canal, because of loss of muscular atony in the facial muscles, and rapid eye movements typical in this phase.Download Supplementary Video 1 ^{(40.6MB, mp4)} via http://dx.doi.org/10.1212/200093_Video_1

The PSG shows the loss of atony in the REM phase, with chin movement in the recording, and emission of a prolonged howl for more than 10 seconds, after which the patient continues in the REM phase, without waking up (Figure; Video 1).

Figure. Nocturnal Polysomnography in REM Phase.

Nocturnal polysomnography, REM phase, with rapid eye movements in the left eye electrooculography (EOG 1) and right eye electrooculography (EOG 2) channels (characteristic of this phase). Appearance of muscle contraction and loss of atony in the “chin” muscle activity channel (white arrow).

Prolonged howling is a very rare symptom in sleep disorders, and very atypical in RSBD, so PSG is essential to confirm the diagnosis and rule out other benign parasomnias.

Appendix. Authors

Study Funding

The authors report no targeted funding.

Disclosure

The authors report no disclosures relevant to the manuscript. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.