Global coherence in structured and unstructured discourse types in neurotypical adults

Research on global coherence in neurotypical aging has predominantly focused on different methods of elicitation and their impact on age. The use of structured versus unstructured discourse tasks can have varying effects on global coherence. Comparative studies investigating this effect within Tamil language-speaking populations are scarce. This study seeks to address this gap by examining global coherence in structured and unstructured tasks among speakers of Tamil language.

This study aimed to identify any significant differences in the global coherence of discourse, as measured through structured (picture description) and unstructured (conversation) tasks, in middle-aged and older neurotypical individuals across ages and genders.

Thirty Tamil-speaking individuals participated in the study, which included 15 middle-aged adults (aged 44–59 years) and 15 older adults (aged 60–80 years), with an equal number of males and females. Discourse samples were audio recorded using structured (picture description) and unstructured (conversational discourse) tasks. The picture description task included describing a single picture (of a birthday scene) and a sequential picture stimulus (depicting an argument event). The conversational task consisted of two topics of conversation (family and work) with the investigator. Each discourse task lasted for at least a minute. The recorded samples were transcribed verbatim and analyzed using a 4-point Global Coherence Rating Scale.

Participants exhibited significant differences, with the unstructured discourse task having a significantly higher global coherence rating (p ≤ 0.05) than both structured discourse tasks. The varying cognitive demands, functional purposes, and contextual factors across various discourse elicitation tasks could be attributed to these differences. No significant differences were observed in the coherence ratings between middle-aged and older adults or between genders.

The method used to elicit discourse and the type of discourse need to be considered when exploring global coherence measures. The current study has important methodological implications for the coherence analysis of the Tamil-speaking population in both structured and unstructured tasks.