Differential Validity of K-MoCA-22 Compared to K-MoCA-30 and K-MMSE for Screening MCI and Dementia.

Background and purpose: Since the onset of the coronavirus disease 2019 pandemic, the Telephone-Montreal Cognitive Assessment (T-MoCA) has gained popularity as a remote cognitive screening tool. T-MoCA includes items from the original MoCA (MoCA-30), excluding those requiring visual stimuli, resulting in a maximum score of 22 points. This study aimed to assess whether the T-MoCA items (MoCA-22) demonstrate comparable discriminatory power to MoCA-30 and Mini-Mental State Examination (MMSE) in screening for mild cognitive impairment (MCI) and dementia.

Methods: Participants included 233 cognitively normal (CN) individuals, 175 with MCI, and 166 with dementia. All completed the Korean-MoCA-30 (K-MoCA-30) and Korean-MMSE (K-MMSE), with the Korean-MoCA-22 (K-MoCA-22) scores derived from the K-MoCA-30 responses. A receiver operating characteristic (ROC) curve analysis was conducted.

Results: K-MoCA-22 showed a strong correlation with K-MoCA-30 and a moderate correlation with K-MMSE. Scores decreased progressively from CN to MCI and dementia, with significant differences between groups, consistent with K-MoCA-30 and K-MMSE. The study also explored modified K-MoCA-22 index scores across 5 cognitive domains. ROC curve analysis revealed that the area under the curve (AUC) for K-MoCA-22 was significantly smaller than that for K-MoCA-30 in distinguishing both MCI and dementia from CN. However, no significant difference in AUC was found between K-MoCA-22 and K-MMSE, indicating similar discriminatory power. Additionally, the discriminability of K-MoCA-22 varied by education level.

Conclusions: These results indicate that K-MoCA-22, although slightly less effective than K-MoCA-30, still shows good to excellent discriminatory power and is comparable to K-MMSE in screening for MCI and dementia.