Investigating the Relationship Between Local and Global Coherence and Cognitive Processes in Persian-speaking Elderly Population

Many studies have suggested a relationship between coherence and cognitive processes. This study aims to investigate this hypothesis by assessing the relationship between cognitive variables and coherence in the discourse of 2 groups of Persian-speaking young adults and the elderly.

To evaluate our participants’ cognitive capabilities, we employed the cognitive tests of the mini-mental status test, the Stroop-color task, the digit symbol copy task, the clock-drawing task, and the backward digit span. On the other hand, the specific tasks to evaluate the discourse properties of the participants were the single task of talking and the dual task of talking while walking.

The results demonstrated that the dual task did not impact local coherence while global coherence was significantly disrupted in both tasks. However, the global coherence scale was more negatively affected in the dual task compared to the single task. While the relationship between global coherence and cognitive variables was significant in both tasks, the relationship between global coherence and working memory measures was only significant in the dual task. Furthermore, no relationship was observed between the scale of local coherence and either cognitive or working memory measures. 

Our findings corroborate previous findings that local and global coherence is manipulated by different cognitive processes and the maintenance of global coherence requires more demanding cognitive processes and is disrupted before local coherence occurs.