Clinical, behavioral, and physiological characteristics of isolated rapid eye movement sleep behavior disorder patients with ambulatory dream enactment behaviors.

STUDY

OBJECTIVES

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) involves dream enactment behaviors (DEBs) during REM sleep, accompanied by REM sleep without atonia (RWA). While most DEBs are bed-confined, a minority engage in ambulatory behaviors. This study investigated clinical, behavioral, and physiological characteristics of iRBD patients exhibiting ambulatory behaviors.

METHODS

We retrospectively reviewed electronic medical records of 361 patients with video-polysomnography (v-PSG)-confirmed iRBD (mean age: 66.9 years; 59.0% males). Patients reporting at least one DEB episode involving ambulation out of the bedroom were classified as RBD-walkers; those without any ambulatory episodes as non-walkers. Clinical assessments, dream contents, behaviors, and PSG metrics were compared between groups.

RESULTS

31 patients (8.6%) were categorized as RBD-walkers, none with prior history of sleepwalking. RBD-walkers were more frequently female (64.5% vs. 38.0%, p = 0.006) and showed higher RBDQ-KR Factor 1 scores (15.7 vs. 12.6, p = 0.005). Combined clonazepam-melatonin use was more common among RBD-walkers (38.7% vs. 19.8%, adjusted residual = +2.443). Behaviorally, they frequently exhibited escape-related motor behaviors and object-interactive behaviors. PSG findings revealed preserved sleep architecture, along with elevated RWA and REM EMG amplitude (6.7 μV vs. 3.6 μV, p = 0.009) in RBD-walkers.

CONCLUSIONS

RBD-walkers represent a clinically and physiologically distinct iRBD subgroup, marked by complex ambulatory behaviors, increased treatment demands, and elevated RWA and REM EMG amplitude despite preserved sleep structure. These findings suggest that ambulatory DEB may arise from multifactorial mechanisms beyond simple REM-atonia loss, warranting further investigation for pathophysiology and clinical implications.