An analysis of intrusive error types in Alzheimer's disease and related disorders

Abstract

Evidence suggests that test intrusions, a type of delayed perseveration, occur more frequently during neuropsychological testing of patients with Alzheimer's disease (AD) than with other dementing disorders. The absolute number of test intrusions occurring among AD patients is relatively low, however, making this an insensitive index of AD. Using the Fuld Object Memory Evaluation, we attempted to determine whether other types of intrusive errors might be useful as behavioral markers of early AD. Intrusions were classified into five qualitatively different categories and documented for mild and moderately impaired AD patients, patients with multiple cerebral infarctions who exhibited mild cognitive impairment, and normal age‐equivalent controls. Within our sample we found that specific types of word intrusions possessed a relatively high degree of sensitivity as well as specificity in distinguishing among patient groups.