Abstract

Objective: We established the diagnostic accuracy of the “ABC Dementia Scale” (ABC-DS) for Alzheimer’s disease (AD), which concurrently assesses activities of daily living (“A”), behavioral and psychological symptoms of dementia (“B”), and cognitive function (“C”), using a novel scoring approach called the three-dimensional distance (TDD).
Methods: The ABC-DS has 13 items with nine ordered categorical levels. Caregivers were interviewed using a semi-structured interview. The construct validity, concurrent validity, test-retest reliability, and responsiveness (score changes over 12 weeks) were assessed.
Results: We enrolled 63 participants with probable AD as well as 88, 106, and 55 patients with mild, moderate, and severe AD, respectively. The construct and concurrent validities of each domain score were determined. The TDD accurately discriminated the AD stages and detected score changes indicating disease progression over 12 weeks.
Conclusion: The ABC-DS is stable, accurately stages AD severity, and monitors disease progression. The TDD is a useful algorithm for detecting disease progression.

Keywords: Activities of daily living; Alzheimer’s disease; Cognitive function; Factor analysis; Item response theory; Receiver operating characteristic; Semi-structured interview; Three-dimensional distance; Multi-domain scale