Prognostic utility of the Montreal Cognitive Assessment

The Montreal Cognitive Assessment (MoCA) is a widely applied cognitive screening instrument, with a supplemental Memory Index Score (MIS) which has been suggested to predict conversion from Mild Cognitive Impairment (MCI) to Alzheimer's Clinical Syndrome (ACS). This study compared the prognostic utility of the MIS to other MoCA metrics in predicting conversion to ACS or other dementias (OD). We analyzed National Alzheimer's Coordinating Center data from 2900 participants aged 50 years or older, diagnosed with MCI at baseline, with at least one follow-up visit. Multinomial logistic regression models assessed whether baseline MoCA Total Score (TS) or MIS predicted final diagnoses, and receiver operating characteristic (ROC) curves examined the clinical utility of baseline MoCA TS, MIS, Free Recall Score (FRS) and TS+MIS for identifying ACS converters at 1-, 3-, and 5-year follow-ups. Over an average follow-up of 4.65 years, 26.5% converted to ACS and 7.4% to OD. Higher baseline TS was associated with lower odds of conversion to ACS (OR = 0.82) and OD (OR = 0.86), while higher MIS was associated with lower odds of ACS (OR = 0.82) but not OD (OR = 0.97). For identifying ACS, ROC area under the curve ranges showed modest advantage for FRS (0.70-0.73), MIS (0.71-0.74), and TS+MIS (0.70-0.74) over the TS (0.63-0.70). MoCA memory subscores were the strongest baseline indicator of later ACS conversion, but no cut-off score displayed acceptable sensitivity and specificity. Future research may explore if MoCA memory subscores display greater prognostic utility in combination with other ACS features.