The present study aimed at investigating the topic shift in the discourse of the senile dementia of the Alzheimer's type based on neurolinguistics perspective within the framework of Crow's model (1983). The methodological nature of this quantitative research was casual-comparative; and the data include 20 subjects (10 senile dementia of the Alzheimer's type subjects and 10 normal elderly subjects). To determine the severity of dementia, the Clinical Dementia Rating Scale was administered and subjects with a score (0.5 ≤ X< 2) were selected. Then, they answered the questions about their families, daily activities. Moreover, the conversations were recorded and transcribed. The utterances were coded according to Dijkstra et al. model (2004), and they were categorized according to Crow's model (1983). Finally, the statistic results obtained using of independent t-test. The findings indicate significantly different Topic Shift (P=0.001) and Topic Maintenance (P=0.01) in the discourse of both groups that occurred Within Turn and Across Turn. The results showed that topic shift has much more frequency in the senile dementia of the Alzheimer's type subjects’ discourse occurring more often Within Turn. Also, Topic Initiation was Type of Shift having the most frequency, and also the most important Reason for Shift was related to Failure to Continue. |