Neuropsychological assessment in idiopathic REM sleep behavior disorder (RBD). Does the idiopathic form of RBD really exist?

To evaluate the cognitive performance of patients with idiopathic REM sleep behavior disorder (RBD). The authors studied 17 consecutive patients with idiopathic RBD vs 17 age- and education-matched control subjects. Tests given to each patient and control included Mini-Mental State Examination, verbal and spatial short-term memory, visual selective attention, verbal fluency, prose memory, visuoconstructional abilities, spatial learning, and executive function tests. A self-administered depression rating scale was also used. RBD patients had significantly lower scores than control subjects in two tests: copy of Rey-Osterrieth Figure and Corsi Supraspan Learning. No correlation was found between the results of neuropsychological tests and RBD duration or with polysomnographic findings. Visuospatial constructional dysfunction and altered visuospatial learning may be present in idiopathic RBD. A neuropsychological assessment may be indicated in RBD patients.