Objectives: To determine the clinical usefulness of an electrophysiologic method for evaluating dysphagia and to identify the effects of various head and neck positions on oropharyngeal swallowing.
Design: Experimental, with control group.
Setting: An electromyography laboratory.
Participants: Patients with neurogenic dysphagia (n = 51) and healthy controls (n = 24). Patients were divided into 2 groups: those patients with unilateral lower cranial lesions (n = 9) and those without laterality in the function of the oropharyngeal muscles (n = 42).
Interventions: Subjects were instructed to swallow doses of water, gradually increasing in quantity from 1 to 25 mL under 5 conditions: neutral, chin up, chin tucked, head rotated right, and head rotated left.
Main outcome measures: Change in dysphagia limit through specified head and neck postures. Oropharyngeal swallowing was evaluated by laryngeal movements that were detected by a piezoelectric sensor and electromyography of the submental muscle complex. Laryngeal sensor signals occurring within 8 seconds of a swallow were accepted as a sign of the dysphagia limit.
Results: In the control group, dysphagia limit did not change significantly with changes in head and neck postures, except for the chin-up posture (p <.05) in which piecemeal deglutition occurred when subjects swallowed volumes less than 20 mL. Dysphagia limit improved significantly (p <.05) in 67% of the patients with unilateral lower cranial lesions when the head was rotated toward the paretic side. In dysphagic patients with bilateral symptoms, a significant (p <.01) improvement in dysphagia limit occurred in 50% of patients in chin-tuck position, but in the chin-up position, 55% of the patients experienced a significant (p <.01) decrease in dysphagia limit.
Conclusion: The electrophysiologic method of measuring dysphagia limit confirms neurogenic dysphagia and its severity in the neutral head position. Changes in head and neck positions do not significantly alter dysphagia limit in unimpaired subjects except for the chin-up position. Although the results obtained were not compared with other techniques (eg, videofluoroscopy), this simple electrophysiologic method for describing dysphagia limit may have a place in the evaluation of dysphagia and its variability in various head and neck positions.