Validity, diagnostics and feasibility of the Italian version of the Montreal Cognitive Assessment (MoCA) in Huntington’s disease

Background: This study is aimed at assessing the clinimetric properties and feasibility of the Italian version of the Montreal Cognitive Assessment (MoCA) in patients with Huntington’s disease (HD). Methods: N = 39 motor-manifest HD patients, N = 74 Parkinson’s disease (PD) patients and N = 92 matched HCs were administered the MoCA. HD patients further underwent the Unified Huntington’s Disease Rating Scale (UHDRS), self-report questionnaires for anxiety and depression and a battery of first- and second-level cognitive tests. Construct validity was tested against cognitive and behavioural/psychiatric measures, whereas ecological validity against motor-functional subscales of the UHDRS. Sensitivity to disease severity was tested, via a logistic regression, by exploring whether the MoCA discriminated between patients in Shoulson-Fahn stage ≤ 2 vs. > 2. The same analysis was employed to test its ability to discriminate HD patients from HCs and PD patients. Results: The MoCA converged towards cognitive and behavioural measures but diverged from psychiatric ones, being also associated with motor/functional measures from the UHDRS. In identifying patients with cognitive impairment, adjusted MoCA scores were highly accurate (AUC =.92), yielding optimal diagnostics at the cut-off of < 19.945 (J =.78). The MoCA was able to discriminate patients in the middle-to-advanced from those in the early-to-middle stages of the disease (p =.037), as well as to differentiate HD patients from both HCs (p <.001) and PD patients (p <.001). Conclusions: The MoCA is a valid, diagnostically sound and feasible cognitive screener in motor-manifest HD patients, whose adoption is thus encouraged in clinical practice and research.