Varying patterns of verbal recall, recognition, and response bias with progression of Alzheimer's disease

Aspects of performance on verbal list learning tasks, such as recall, recognition, and response bias, may vary with severity in Alzheimer's disease (AD). We administered a 10-item, single-category word list learning test using selective reminding procedures to 188 patients with probable AD and 36 healthy normal controls with equivalent age and education. We analyzed the total number of words recalled as well as discrimination and response bias indexes derived from signal detection theory. Recall and discrimination were impaired in patients with probable AD compared to controls, and recall scores were more sensitive to dementia severity than discrimination. While many AD patients showed a liberal response bias, their response bias varied considerably within patient groups and did not correlate with disease severity.