The Montreal Cognitive Assessment as a screening tool for cognitive dysfunction in Huntington's disease.

Cognitive dysfunction is one of the hallmarks of Huntington's disease (HD) and may precede the onset of motor symptoms. The Montreal Cognitive Assessment (MoCA), a brief cognitive screening instrument with high specificity and sensitivity for detecting early cognitive impairments, has not been studied in the HD population. In this study, we compare the MoCA with the mini-mental state examination (MMSE) as a screening tool for cognitive dysfunction among 53 patients with HD. The mean MMSE score was 26 +/- 2.4, and mean MoCA score was 21 +/- 4.4. Twenty-one patients (81%) of those who scored >or=26 on the MMSE had the MoCA score <26. Thirty-two patients (78%) of those who scored >or=24 on the MMSE had the MoCA score <24. The MoCA may be a more sensitive screening tool for cognitive impairments in HD relative to the MMSE.