Background: The Hong Kong version of Montreal Cognitive Assessment (HK-MoCA) has been used to screen for dementia, but it has not been validated to delineate the stages of Alzheimer disease (AD). This study aimed to determine the cut-off score ranges for mild, moderate, and severe AD.
Methods: The HK-MoCA score was matched against the Clinical Dementia Rating on 155 patients with AD. Investigators performing the HK-MoCA and Clinical Dementia Rating were blinded to each other. Receiver-operating characteristic analysis was used to determine the cut-off scores between different stages of AD (mild, moderate, and severe stage). A secondary analysis with adjustments for age and education received were also performed.
Result: The cut-off score in HK-MoCA was ≤4 for those with severe AD (sensitivity 84.4%, specificity 91.9%, area under curve=0.92, P<0.001) and 5 to 9 for those with moderate AD (sensitivity 86.3%, specificity of 93.3%, area under curve=0.953, P<0.001). With adjustments for age and education, the cut-off score for moderate AD was adjusted to 5 to 8, whereas the cut-off score for severe AD remained unchanged.
Conclusions: The severity of AD could be delineated using the HK-MoCA for the Cantonese-speaking population in Hong Kong, and the effect of education on the cut-off score needs further investigation.