Speech Performance among Healthy Malay Female Speakers during Dual Tasks and Sentence Complexity

Objectives: This study aimed to identify how different dual tasks influence speech performance among young Malay speakers by manipulating the complexity of sentences. Fifteen female speakers (20-30 years old) were audio recorded while executing a series of simple and complex sentence repetition tasks. Methods: Hierarchical linear modeling was conducted to examine the effects of task (speech task only, speech + cognitive tasks, speech + linguistic tasks, and speech + manual tasks) and sentence complexity (simple vs. complex), as well as their interaction on 3 outcome measures (word accuracy rate [WAR], response reaction time [RRT], and duration of sentence [DoS]). Results: Significantly higher WAR were found when participants read the sentences only compared to when they completed another task simultaneously. The pairwise comparison further revealed that the conditions of speech + manual tasks produced the lowest WAR. For RRT, participants responded significantly faster when they only read the sentences (mean = 1.36, SE = 0.17) than when they read the sentences and conducted another task at the same time (mean = 1.66, SE = 0.14; p < 0.0001). A pairwise comparison showed that the conditions of speech + manual tasks produced the longest DoS. Neither the effect of sentence complexity nor the interaction between task and sentence complexity was statistically significant across WAR, RRT, and DoS. Conclusions: The results augment what is known about interference between speech and other concurrent tasks and provides evidence that divided attention affects manual task performance more than other tasks. In addition, sentence complexity did not affect speech performance in healthy adults. This paradigm could be used in future studies to serve as a clinical marker that can potentially distinguish mild cognitive impairment from normal aging.