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

OBJECTIVE: To evaluate the cognitive performance of patients with idiopathic REM sleep behavior disorder (RBD).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: Visuospatial constructional dysfunction and altered visuospatial learning may be present in idiopathic RBD. A neuropsychological assessment may be indicated in RBD patients.