Conversations used to communicate with others often convey meanings beyond their explicit content. These are referred to as indirect speech acts, which require understanding the speaker's intentions through reasoning about the conversational context a...
Conversations used to communicate with others often convey meanings beyond their explicit content. These are referred to as indirect speech acts, which require understanding the speaker's intentions through reasoning about the conversational context and the surrounding circumstances. Dementia patients often exhibit impaired executive functions in the frontal lobe, responsible for cognitive processes such as reasoning and problem-solving. This impairment is expected to affect their ability to comprehend indirect speech acts. However, research on this topic remains insufficient. Therefore, this study aims to explore the auditory indirect speech act comprehension characteristics of individuals with dementia. The study involved 22 participants aged 65 or older residing in Gyeongbuk, Daegu, and Ulsan, consisting of 11 individuals with dementia and 11 normal elderly. They were asked to perform a newly developed indirect speech act comprehension task. The performance of the two groups was compared based on overall task scores, response times per question, sentence types, illocutionary act types, and error types. Additionally, correlations between the comprehension task and executive functions were examined. The results demonstrated that the dementia exhibited significantly lower performance in the indirect speech act comprehension task compared to the normal elderly, revealing difficulties in comprehending indirect speech acts. This deficit is likely due to impaired executive functions in the frontal lobe. Although significant differences in task performance scores were observed between the two groups across sentence types, the differences based on sentence type alone were not statistically significant. Significant differences were found between groups based on illocutionary act types, with statistical significance in both group differences and variations in act types. Both groups showed significant differences in declarative and imperative acts, while the normal elderly also showed differences in requestive acts. Both groups experienced the greatest difficulty in understanding declarative, requestive, and imperative acts, in that order. In addition, The dementia exhibited slower response times across all task types compared to the normal elderly, with significant group differences. This suggests inefficiencies in top-down processing among individuals with dementia. No significant differences in response times were found based on sentence or illocutionary act types, nor were there interactions between group and sentence or illocutionary act types. These findings indicate that comprehension and responses to indirect speech acts were not influenced by sentence or illocutionary act types. Similarly, error analysis revealed no significant differences in error rates between the groups. However, within-group comparisons showed statistically significant differences in error types, with both groups making more literal errors. This suggests a failure to suppress the literal meaning of sentences and infer their implicit meanings. Finally, A positive correlation was found between performance on the auditory indirect speech act comprehension task and the Verbal Fluency Test, an executive function measure from the Seoul Neuropsychological Screening Battery-Core (SNSB-C). This suggests that poor performance on the comprehension task may reflect deficits in executive functions. This study provides valuable insights into the auditory indirect speech act comprehension abilities of individuals with dementia and serves as foundational data for developing treatment guidelines or therapeutic materials tailored to this population.