Effects of divided attention on swallowing in healthy participants

Swallowing impairments are treated mostly behaviorally. It is requisite to understand the relationship of cognition, specifically attention, with swallowing since so many swallowing impairments occur concomitantly with cognitive disorders. This study examined the hypothesis that attentional resources are required during swallowing. The approach involved a dual-task, reaction time (RT) paradigm in ten healthy, nonimpaired participants. Baseline measures were obtained of the duration of the anticipatory phase and of the oropharyngeal phase of swallowing and the RTs to nonword auditory stimuli. A dual-task then required participants to swallow 5 ml of water from an 8-oz. cup while listening for a target nonword presented auditorily during the anticipatory or the oropharyngeal phase. Target stimuli were randomized across baseline and dual-task trials. Duration of the anticipatory phase and of the oropharyngeal phase of swallowing and duration of the RT baseline trial and of the dual-task trial were determined. Results showed a statistically significant increase in speed of the anticipatory phase, relative to the oropharyngeal phase, for swallowing during the dual-task. RTs were slowed for both the anticipatory and the oropharyngeal phase during the dual-task, although neither of these was statistically significant. Clinical implications of these data suggest that disruptive stimuli in the environment to nonimpaired individuals may alter feeding but have little effect on the oropharyngeal swallow.