Diagnostic accuracy of the ADAS-Cog-13 as a cognitive screening tool in older adults with focal epilepsy: A multicenter cross-sectional study.

OBJECTIVE

Cognitive impairment is common among older adults with epilepsy, and although the Montreal Cognitive Assessment (MoCA) has demonstrated validity as a screening tool in this population, additional efficient screening options are needed. Here we examine, for the first time, the diagnostic accuracy of the Alzheimer's Disease Assessment Scale-Cognitive-13 Item Subscale (ADAS-Cog-13) as a screening tool to identify cognitive impairment in older adults with focal epilepsy.

METHODS

Participants included 83 adults (ages ≥55) with focal epilepsy from the Brain, Aging, and Cognition in Epilepsy (BrACE) study and 83 age-, sex-, and education-matched cognitively healthy controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI-3). All completed the ADAS-Cog-13 and a comprehensive neuropsychological battery that was analyzed through the International Cognitive Disorders in Epilepsy (IC-CoDE) system to identify cognitive phenotypes (intact vs. impaired). Performance on the individual ADAS-Cog-13 total score and items was assessed, clinical and sociodemographic features characterized, and diagnostic efficiency statistics determined and compared with MoCA performance.

RESULTS

Focal epilepsy participants (mean age = 66.4 years) performed significantly worse across the ADAS-Cog-13 total score and 8 of the 13 individual test items compared with controls. The largest effect sizes were observed on verbal learning and memory tasks, particularly word recall (d = .87) and delayed word recall (d = 1.06). An ADAS-Cog-13 total score of ≥15 yielded optimal diagnostic efficiency (67.5% accuracy, 68.8% sensitivity, 66.7% specificity) for identifying cognitive impairment-similar to MoCA performance.

SIGNIFICANCE: The ADAS-Cog-13 is sensitive to detecting cognitive impairment in older adults with focal epilepsy and may represent a scalable screening option in this population. Additional comparative studies in older epilepsy populations are needed to determine the sensitivity of this measure to longitudinal change, cross-cultural applicability, and availability across languages.

PLAIN LANGUAGE SUMMARY: Cognitive decline is common among older adults with epilepsy. Although the Montreal Cognitive Assessment (MoCA) has been shown to be a valid screening tool in this population, additional options are needed. The ADAS-Cog-13 may be a useful screening option in epilepsy research and clinical care, although additional studies are needed to compare it with other cognitive screening tests and to confirm its applicability for clinical care and across healthcare settings and cultures.