Comparison of Alternate and Original Items on the Montreal Cognitive Assessment

BACKGROUND: The Montreal Cognitive Assessment (MoCA) is a screening tool for mild cognitive impairment (MCI) in elderly individuals. We hypothesized that measurement error when using the new alternate MoCA versions to monitor change over time could be related to the use of items that are not of comparable difficulty to their corresponding originals of similar content. The objective of this study was to compare the difficulty of the alternate MoCA items to the original ones. METHODS: Five selected items from alternate versions of the MoCA were included with items from the original MoCA administered adaptively to geriatric outpatients (N = 78). Rasch analysis was used to estimate the difficulty level of the items. RESULTS: None of the five items from the alternate versions matched the difficulty level of their corresponding original items. CONCLUSIONS: This study demonstrates the potential benefits of a Rasch analysis-based approach for selecting items during the process of development of parallel forms. The results suggest that better match of the items from different MoCA forms by their difficulty would result in higher sensitivity to changes in cognitive function over time.