REM sleep behavior disorder and epileptic phenomena: Clinical aspects of the comorbidity

Purpose: To document the occurrence of REM sleep behavior disorder (RBD) episodes in patients with epilepsy, and of interictal EEG epileptiform abnormalities (IEA) in patients with idiopathic RBD. Methods: Consecutive observations in a tertiary epilepsy center and a tertiary sleep center. RBD diagnosis was based on standard clinical and video-polysomnographic findings. Results: Co-occurrence of epileptic seizures and RBD episodes was found in six cases (all men; mean age 70.5 ± 11.1 years). Focal, isolated, sporadic sharp waves during wakefulness and/or during sleep were documented in 9 out of 34 (26.4%) patients with idiopathic RBD; no significant differences in age at onset and duration of RBD emerged between RBD patients with and without IEA. Conclusions: RBD episodes can occur in epilepsy patients and focal IEA in patients with idiopathic RBD. This, apart from being a possible cause for misdiagnosis, may indicate a possible link between the two disorders. Further systematic investigations of the occurrence of RBD episodes in epilepsy will help to establish the real extent of this comorbidity and its ultimate neurobiological significance. © 2006 International League Against Epilepsy.