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.