Characteristics of conversation in frontotemporal dementia: Comparison with dementia of the Alzheimer's type

Abstract

Objectives: Due to the general damage to the frontal lobe, patients with frontotemporal dementia (FTD) could have pragmatic difficulties in conversation from early stages. The purpose of this study is to investigate the characteristics of conversation in patients with FTD through a comparison with dementia of the Alzheimer's type (DAT), and then examine the relationship with general cognitive functions. Methods: Fifty subjects (FTD group = 10, DAT group = 20, normal adults [NA] group = 20) were engaged in free conversation on various topics. Results: First, regarding conversation participation, the FTD group showed significantly lower performance than the DAT group and the NA group in the frequency of conversation turn exchanges and the number of utterances during conversation turns. Second, regarding conversation topic, the FTD group showed a significantly lower number of topics, a lower frequency of conversation turns per topic, a lower rate of topic maintenance, and a lower rate of topic switching, but a significantly higher rate of topic breakaway than the DAT group and the NA group. Third, with regard to conversation disturbance, the FTD group did not show a significant difference in performance from the DAT group or the NA group. Conclusion: It is possible that FTD patients displayed a smaller number of utterances due to lack of motivation caused by the damage to the medial frontal lobe and have difficulties in topic maintenance and various topic initiation due to dysfunction of general language processing abilities and working-memory capacity caused by the damage to the dorsolateral area.