Non-invasive assessment of swallowing and respiration in Parkinson's disease

Oro-pharyngeal dysphagia is well recognised but often underestimated in people with Parkinson's disease. Asymptomatic patients may fail to receive timely advice or therapy, thus placing them at risk. The aim of this study was to determine whether subclinical abnormalities in swallowing and discrete changes in function such as those produced by prompting can be detected by non-invasive methods. We examined 12 people with idiopathic Parkinson's disease and 14 elderly comparison subjects. Five components of respiratory synchronisation and swallowing efficiency were monitored using the Exeter Dysphagia Assessment Technique. Ten feeding trials were administered under standard quiet conditions. The patients were then restudied using verbal prompts when the spoon was presented to the mouth. The duration of two oro-pharyngeal events and the frequency of respiratory variables were compared for unrelated and related samples. Results showed the oral and pharyngeal parts of the swallow to be significantly slower in those with Parkinson's disease. These patients required significantly more swallows to clear a 5-ml bolus, and fewer swallows were followed by expiration. When the patients were verbally prompted, there was a significant reduction in the duration of the oral part. This study demonstrates that non-invasive methods can be used to detect subclinical difficulties with swallowing amongst a group of asymptomatic patients with PD and that these methods are sensitive to small changes in function produced by a verbal cue.