Semantic Intrusion Error Ratio Distinguishes Between Cognitively Impaired and Cognitively Intact African American Older Adults.

Background: Semantic intrusion errors on memory tests may represent very early cognitive changes associated with elevated Alzheimer's disease pathology within the brain, including amyloid-β (Aβ). Subscales that measure proactive semantic interference (PSI) and intrusions related to PSI on the Loewenstein Acevedo Scales of Semantic Interference and Learning (LASSI-L) have been associated with high levels of brain amyloid load, structural changes on brain MRI in Hispanic and non-Hispanic groups. It is presently unknown whether intrusion errors or other measures of the LASSI-L can differentiate between African-American (AA) older adults diagnosed with amnestic mild cognitive impairment (aMCI) or classified as cognitively normal (CN).

Objective: This study examined the extent to which a high percentage of semantic intrusion errors on LASSI-L subscales susceptible to PSI and other LASSI-L measures could differentiate between AA aMCI and CN groups.

Methods: Forty-eight AA older adults were recruited (27 CN and 21 aMCI) and received a through clinical and neuropsychological evaluation. The LASSI-L was administered independent of diagnostic classification.

Results: With and without statistical adjustment for literacy, AA aMCI participants scored lower on all LASSI-L measures. ROC analyses revealed an area under the curve exceeding 90% and correctly classified 86% of AA aMCI with 82% specificity for AA CN participants.

Conclusions: Percentage of intrusion errors on the LASSI-L subscales susceptible to PSI differentiated AA aMCI from AA CN. This adds to emerging evidence indicating that the LASSI-L may be culturally appropriate and can differentiate between aMCI and CN in diverse ethnic/cultural groups.