Clinical significance of REM sleep behavior disorder in Parkinson's disease

Objective: Rapid eye movement (REM) sleep behavior disorder (RBD) may be a risk factor for dementia development in patients with Parkinson's disease (PD); however, the role of subclinical RBD remains unknown. Patients with PD and clinical RBD, subclinical RBD, or with normal REM sleep were examined in a cross sectional study and a longitudinal follow-up. Methods: Interviews regarding RBD symptoms and polysomnographies were performed on 82 PD patients divided into RBD subcategories based on the presence/absence of REM sleep without atonia (RWA) and/or RBD symptoms. Descriptive variables were compared and patients were followed-up longitudinally for 21.4 +/- 10.8 months. Results: The existence of RBD, but not subclinical RBD, was associated with orthostatic hypotension and levodopa dose equivalents (LDEs) in patients with PD. Kaplan-Myer curves indicated that the occurrence of dementia in the PD group with clinical RBD was significantly faster than in the PD group with normal REM sleep (p = 0.013). A Cox hazard regression analysis revealed that development to PD with dementia was only significantly associated with the presence of clinical RBD (hazard ratio: 14.1, p = 0.017). Conclusion: Clinical RBD symptoms, but not subclinical RBD, were associated with the development of dementia in PD. (C) 2012 Elsevier B.V. All rights reserved.