Pattern of intrusions in verbal recall: Comparison of Alzheimer's disease,Parkinson's disease, and frontal lobe dementia

Although some researchers have suggested that intrusions in word list learn ing are more frequent in Alzheimer's disease, recent studies have shown tha t this might not be true. In fact, intrusions are common in many neurologic al degenerative diseases. The goal of the present study was to examine the types of intrusions made by three groups of patients, namely patients with Parkinson's disease (PD), Alzheimer's disease (AD), and dementia with promi nent frontal lobe semiology (FD). Although PD patients learned more words ( trials 1 to 5 on the RAVLT) than the two other groups, there was no signifi cant difference in the total number of intrusions. However, significant dif ferences between groups were observed for nonrelated intrusions, the propor tion of PD patients (15.48) being lower than the proportion of AD (45.5%) a nd FD (45.8%) patients with this type of intrusions. No other type of intru sions (same category, recurring, phonemic) significantly differentiated bet ween the three groups. The proactive interference effect (PI), measured as the difference between first recall of list A and list B recall, was strong er in PD than in the two other groups, reflecting the strong positive corre lation between total number of words recalled on the RAVLT and severity of the PI effect. Frier list intrusions (intrusions from list A while recallin g list B items) were significantly more pronounced in FD than in the two ot her groups. Finally, free associations (series of intrusions related to one another but not to the target items) were observed almost exclusively in F D patients. Three findings illustrate some qualitative differences between various neurological degenerative diseases. They also stress the marked sim ilarities between AD and FD with regards to verbal learning. (C) zool Acade mic Press.