Audiovisual analysis of the diagnostic video polysomnography in patients with isolated REM sleep behavior disorder.

Background: The diagnosis of isolated REM sleep behavior disorder (IRBD) requires video polysomnography (V-PSG) showing increased muscle activity and abnormal behaviors in REM sleep.

Objective: To describe in IRBD the behavioral manifestations occurring during REM sleep in the diagnostic V-PSG.

Methods: This is a systematic audiovisual V-PSG analysis of consecutive IRBD patients. According to the International RBD Study Group recommendations, REM sleep movements and vocalizations were classified into categories and severity.

Results: We analyzed the V-PSG of 62 IRBD patients with a mean age of 67.6 ± 8.1 years. Of 6,330 30-s epochs of REM sleep, 55.1% epochs exhibited motor events, 5.5% contained vocalizations and 39.4% were silent. Among the epochs with motor manifestations, 66.1% contained simple minor movements, 25.0% simple major and 8.9% complex movements. Motor severity of the epochs was mild in 82.2%, moderate in 13.2% and severe in 4.6%. Most movements were bilateral (62.4%) and located in the upper limbs (42.5%). Of the epochs with vocalizations, 61.5% were simple minor, 20.7% complex and 17.8% simple major of mild (72.7%), moderate (23.0%) and severe (4.3%) severity. Complex movements occurred in 87.1% of the patients and complex vocalizations in 38.7%.

Conclusions: In IRBD, the most common manifestations in REM sleep are simple minor movements and vocalizations of mild intensity. Complex movements are observed during REM sleep in most patients but are much less frequent than simple minor and major motor events. These findings should be considered for the routine diagnosis of IRBD when reviewing the V-PSG studies.