Swallowing performance during cognitive tasks in healthy adults

Dysphagia frequently co-occurs with cognitive impairment, suggesting that swallowing may involve cognitive processes. However, the relationship between cognitive load and swallowing performance remains unclear. This study aimed to examine the effects of different levels of cognitive load on swallowing performance under dual-task conditions in healthy adults.

Forty-three graduate students (mean age: 24.49 ± 1.63 years, male/female: 22/21) were recruited and performed five tasks: swallowing single task (SST), low-load cognitive single task (ST_low), high-load cognitive single task (ST_high), low-load cognitive-swallowing dual task (DT_low), and high-load cognitive-swallowing dual task (DT_high). Here, a dual-task refers to the concurrent execution of a swallowing task and a cognitive task, designed to evaluate the competition for attentional resources and performance trade-offs. The low-load cognitive task consisted of a digit forward-span task, while the high-load cognitive task involved a digit backward-span task, which demands greater cognitive processing complexity and working memory load. Swallowing measures (e.g., swallowing volume) and cognitive task accuracy were recorded, and dual-task cost (DTC) was calculated to evaluate performance changes under dual-task conditions.

Swallowing volume differed significantly among SST, DT_low, and DT_high (p < 0.05), with lower volume in DT_high compared to SST (p < 0.05). Cognitive accuracy was significantly lower in DT_high than in DT_low (p < 0.05), indicating greater interference under high cognitive load.

The findings confirm that swallowing engages executive function and attentional resources, and suggest that participants prioritize swallowing performance during dual-task conditions by adjusting prefrontal activation patterns rather than increasing overall cortical activation to manage interference. This study provides preliminary evidence for the cognitive involvement in swallowing and highlights the need to consider cognitive load in dysphagia assessment and rehabilitation.