A Validation Study of the Hong Kong Brief Cognitive Test for Screening Patients with Mild Cognitive Impairment and Alzheimer’s Disease

The Hong Kong Brief Cognitive Test (HKBC), a brief instrument designed to screen for cognitive impairment in older adults, has been validated in Cantonese-speaking populations and has shown better performance than the Mini-Mental State Examination (MMSE) in detecting both mild and major neurocognitive disorder (NCD). This study aimed to validate the HKBC for detecting patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) in a Mandarin-speaking Chinese population. Two hundred forty-eight patients with aMCI, 67 patients with mild AD and 306 healthy controls (HCs) were recruited for this study and completed both the HKBC and the MMSE. The performance of the HKBC and MMSE in distinguishing patients with aMCI from HCs and distinguishing patients with AD from patients with aMCI was compared in the whole population and in age- and education-stratified subgroups. The optimal HKBC cutoff score for distinguishing patients with aMCI from HCs was 23, and the optimal cutoff score for distinguishing patients with AD from patients with aMCI was 17. The HKBC significantly outperformed the MMSE at differentiating patients with aMCI from HCs in the whole population (z = 12.38, p < 0.01) and all subgroups stratified by age or education. Regarding the discrimination of patients with AD from patients with aMCI, the HKBC showed better performance than the MMSE in the oldest subgroup (z = 2.18, p = 0.03). The HKBC is a sensitive and specific screening tool for detecting aMCI and AD in the Chinese population across age groups and educational levels.