Abstract
BACKGROUND: Difficulties in inhibition and self-monitoring are early features of incipient Alzheimer's disease and may manifest as susceptibility to proactive semantic interference. However, due to limitations of traditional memory assessment paradigms, recovery from interference effects following repeated learning opportunities has not been explored. OBJECTIVE: This study employed a novel computerized list learning test consisting of repeated learning trials to assess recovery from proactive and retroactive semantic interference. DESIGN: The design was cross-sectional. SETTING: Participants were recruited from the community as part of a longitudinal study on normal and abnormal aging. PARTICIPANTS: The sample consisted of 46 cognitively normal individuals and 30 participants with amnestic mild cognitive impairment. MEASUREMENTS: Participants were administered the Cognitive Stress Test and traditional neuropsychological measures. Step-wise logistic regression was applied to determine which Cognitive Stress Test measures best discriminated between diagnostic groups. This was followed by receiver operating characteristic analyses. RESULTS: Cued A3 recall, Cued B3 recall and Cued B2 intrusions were all independent predictors of diagnostic status. The overall predictive utility of the model yielded 75.9% sensitivity, 91.1% specificity, and an overall correct classification rate of 85.1%. When these variables were jointly entered into receiver operating characteristic analyses, the area under the curve was .923 (p<.001). CONCLUSIONS: This novel paradigm's use of repeated learning trials offers a unique opportunity to assess recovery from proactive and retroactive semantic interference. Participants with mild cognitive impairment exhibited a continued failure to recover from proactive interference that could not be explained by mere learning deficits.