Montreal Cognitive Assessment for the screening and prediction of cognitive decline in early Parkinson's disease

Abstract

Background: Early diagnosis of cognitive impairment in PD would allow appropriate monitoring and timely intervention to reduce the progression to dementia (PDD).

Objective: To study the usefulness of the Montreal Cognitive Assessment (MoCA) in the screening for mild cognitive impairment (PD-MCI) and its predictive utility in determining longitudinal cognitive decline in PD.

Methods: Prospective longitudinal study of patients with mild PD. PD-MCI and PDD was diagnosed based on the Movement Disorder taskforce (MDS) criteria. Receiver Operating Characteristic analyses and Cox regression analyses were performed.

Results: 95 patients; mean age 66.37 (SD 7.86); mean H&Y score of 1.99 (SD 0.45) were studied. At baseline, 34 patients fulfilled the MDS criteria for PD-MCI. MoCA, compared to the MMSE had a high discriminatory power in detecting PD-MCI [Area Under Curve (AUC) of 0.912, p < 0.001]. A MoCA score of ≤26 provided a sensitivity of 93.1% for the diagnosis of PD-MCI. In the longitudinal cohort over 2 years, baseline MOCA was useful in predicting cognitive decline (AUC of 0.707, p = 0.05). With Cox regression analyses, a 1-point lower score on baseline MoCA was associated with a 34% increased risk of cognitive decline [Hazard ratio (HR) 1.34; 95% CI: 1.03-1.74: p = 0.029]. A baseline MoCA ≤26 was highly predictive of progressive cognitive decline (HR 3.47, 95% CI: 2.38-5.07; p < 0.01).

Conclusions: MoCA is a reliable tool in predicting cognitive decline in early PD. A MoCA score of ≤26 significantly increases the risk for progressive cognitive decline.

Keywords: Cognitive functions; Dementia; Parkinson's disease.