Verbal perseveration in individuals with Alzheimer's disease

Perseveration has been described as a reliable indicator of disturbed brain function and is a common characteristic of neurological conditions such as Alzheimer's disease (AD). This article will begin with a review of recent theories that account for the phenomenon of perseveration, and data from a National Institute on Deafness and Other Communication Disorders (NIDCD)--supported study further delineate the nature of perseveration among individuals with AD. The study investigated the frequency of verbal perseveration in individuals with AD in relation to task type, mental status, and performance on attention and memory tests. Thirty Alzheimer's patients and 40 healthy elders were given a confrontation naming, generative naming, and picture description test. Perseveration was defined as a proportion of total number of responses. Data analysis revealed that individuals with AD perseverated more than normal elders did, but variability was high. Generative naming elicited more perseveration than either confrontation naming or picture description did. When overall frequency of perseveration was correlated with mental status and performance on attention and memory tests, seemingly paradoxical results were obtained, probably because the unique cognitive demands of each language test affected the probability of perseveration differently. Nonparadoxical, strong positive correlations were obtained, however, between language test scores and performance on tests of attention, memory and mental status.