Effects of divided attention on swallowing in persons with idiopathic Parkinson's disease

The purpose of this study was to determine whether attentional resources are involved in swallowing in persons with idiopathic Parkinson's disease, and if so, in which phase(s) of swallowing. The approach involved a dual-task, reaction time (RT) paradigm using ten participants with Parkinson's disease. Single-task baseline measures were obtained for durations of the anticipatory phase and oropharyngeal phase of swallowing and RTs were obtained for 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 oropharyngeal phase. Target stimuli were randomized across baseline and dual-task trials. Durations of the anticipatory and oropharyngeal phases of swallowing and RTs during baseline and dual-task trials were determined. Results showed a nonsignificant change in speed of completion for both the anticipatory phase and the oropharyngeal phase of swallowing during dual-task trials. However, there was a statistically significant increase in RT during the anticipatory phase during the dual-task condition. RT during the oropharyngeal phase remained unaffected. Given a need for additional research using more complex competing tasks, these data on attention are consistent with earlier claims of an automatic, nonresource-demanding, oropharyngeal swallowing mechanism that is preserved for persons with early-to-mid-stage Parkinson's disease. Clinical implications of these data suggest that disruptive environmental stimuli to individuals with early-to-mid-stage Parkinson's disease may alter feeding but have little effect on the oropharyngeal swallow.