The Montreal Cognitive Assessment: a screening tool for mild cognitive impairment in REM sleep behavior disorder.

Mild cognitive impairment (MCI) is a frequent feature in idiopathic REM sleep behavior disorder (RBD), a sleep disturbance that can be a preclinical stage of Parkinson's disease or Lewy body dementia. We evaluated the sensitivity and specificity of two brief screening tools, the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), in detecting MCI in idiopathic RBD. Thirty-eight idiopathic RBD patients underwent a comprehensive neuropsychological assessment, including the MoCA and the MMSE. Receiver operating characteristic curves were created for the MoCA and the MMSE to assess their ability to identify MCI in idiopathic RBD patients, with neuropsychological assessment as the gold standard. For the MoCA, a normality cutoff of 26 yielded the best balance between sensitivity (76%) and specificity (85%) with a correct classification of 79%. For the MMSE, the optimal normality cutoff was 30, with a sensitivity of 84% and a specificity of 54% and a correct classification of 74%. The MoCA is superior to the MMSE in detecting MCI in idiopathic RBD patients, showing good sensitivity and very good specificity. (c) 2010 Movement Disorder Society.