Objective: To determine an optimal cutoff point of the MoCA for cognitive impairment detection in Mexican persons with PD.

Background: Cognitive impairment (CI) is frequent in persons with Parkinson’s disease (PwP). Whereas 19–38% of PwP develop a degree of CI, up to 80% could progress to dementia (PDD). Neuropsychological testing is needed to classify CI subtypes, as well as to identify PwP at higher risk of developing PDD, furthermore implementing timely therapeutic strategies and improving patient care and well-being [1]. The Montreal Cognitive Assessment (MoCA) is a screening tool recommended to assess CI in PD. Its Spanish version is a valid and reliable tool for Mexican elderly people [2]. Nevertheless, the cutoff point for PD-CI might need adjustment considering the lower educational level in Mexico [3].

Method: 91 Mexican PwP (60.4% males; 60.3±10.0 years-old) were included in this cross-sectional study. Cognitive assessment was carried out with the Mexican version of the MoCA (v8.3) and a comprehensive neuropsychological battery, which explored 5 cognitive domains, with 2 tests for each domain [table1]. Scores from each test were converted to normative values (percentile scores and Z-scores) based on Mexican norms. Cognitive impairment was diagnosed according to the Movement Disorder Society Task Force criteria [1], and considering a Z-score of less than -1.5 either in one test of at least two different domains or in both tests from one single domain.

Results: Mean education and PD evolution years were 11.6±4.9 and 8.7±4.8, respectively. MoCA score was 25.8±3.5 points. The prevalence of CI was 30.8% using the neuropsychological battery as the gold standard. Sensitivity of 42.9% (24.5-62.8), specificity of 77.8% (65.5-87.3), PPV of 46.1% and NPV of 73% were calculated with a diagnostic accuracy of 67.1% (56.4-76.6) for a cutoff point of 24 for PD-CI (AUC=0.634 [0.508-0.759], 95% CI, p=0.043; Youden index (J)=0.21) [figure1].

Conclusion: Comprehensive neuropsychological testing cannot be substituted by global cognitive scales. Screening cognitive impairment in Mexican PwP using the MoCA could benefit by adjusting the cutoff point to ≤24, considering the lower level of education in the general Mexican population. Therefore, optimizing the diagnostic, therapeutic, and research resources aimed to address PD-CI patients not only in Mexico but also in other resource-limited countries.

References: [1] Litvan I, Goldman J, Tröster A, et al. Diagnostic criteria for mild cognitive impairment in Parkinson’s disease: Movement Disorder Society Task Force Guideline. Mov Disord. 2012;27(3):349-56.
[2] Aguilar-Navarro SG, Mimenza-Alvarado AJ, Palacios-García AA, et al. Validity and Reliability of the Spanish version of the Montreal Cognitive Assessment (MoCA) for the Detection of Cognitive Impairment in Mexico. Rev Colomb Psiquiatr. 2018;47(4):237-43.
[3] Borda MG, Reyes-Ortiz C, Pérez-Zepeda MU, et al. Educational level and its association with the domains of the Montreal Cognitive Assessment Test. Aging Ment Health. 2019;23(10):1300-06.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/montreal-cognitive-assessment-cutoff-point-for-cognitive-impairment-in-mexican-subjects-with-pd-a-neuropsychological-approach/