The effect of rivastigmine on connected speech assessed by the Boston Cookie Theft picture description task in patients with early Alzheimer’s disease

Abstract

Background: Rivastigmine delays cognitive deterioration in patients with mild to moderate Alzheimer’s disease (AD). Treatment with rivastigmine results in beneficial effects on cognitive function, ADL performance, global function and behavior, when a daily dose of 6-12 mg is used for at least six months. However, the effect of rivastigmine on connected speech is almost unknown. Aims: This study aimed (i) to compare the connected speech of early stage AD patients with the connected speech of cognitively normal elderly people, and (ii) to compare the connected speech of the same group AD patients before and after treatment with rivastigmine. Methods and procedure: Connected speech of AD patients (N= 28) elicited by the Boston Cookie Theft Picture Description Task was compared with that of healthy elderly volunteers (N=29). By using the same method, AD patients’ connected speech was transcribed and analyzed before and after treatment with rivastigmine on six variables, namely number of essential concepts, total number of words, conciseness index, empty words, TTR-content words, and semantic paraphasias. Furthermore, we checked if the participants showed associative behavior, and if they gave comments on the picture. Outcomes and results: This study demonstrated that there was no significant difference in connected speech performance of AD patients and controls. In addition, this study showed that the differences between assessment one and two of both groups were not significant for all variables. Conclusions: The Cookie Theft Description Task is not a good method to discriminate between AD patients in the early stage and healthy elderly controls. It is furthermore demonstrated that rivastigmine positively affects connected speech of AD patients in the early stage, since they performed at an equal level at both assessments.