The effect of head and neck positions on oropharyngeal swallowing: A clinical and electrophysiologic study

Objectives: To determine the clinical usefulness of an electrophysiologic m ethod 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 contr ols (n = 24). Patients were divided into 2 groups: those patients with unil ateral lower cranial lesions (n = 9) and those without laterality in the fu nction of the oropharyngeal muscles (n = 42). Interventions: Subjects were instructed to swallow doses of water, graduall y increasing in quantity from 1 to 25mL under 5 conditions: neutral, chin u p, 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 movemen ts that were detected by a piezoelectric sensor and electromyography of the submental muscle complex. Laryngeal sensor signals occurring within 8 seco nds 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 volu mes less than 20mL. Dysphagia limit improved significantly (p < .05) in 67% of the patients with unilateral lower cranial lesions when the head was ro tated toward the paretic side. In dysphagic patients with bilateral symptom s, a significant (p < .01) improvement in dysphagia limit occurred in 50% o f patients in chin-tuck position, but in the chin-up position, 55% of the p atients experienced a significant (p < .01) decrease in dysphagia limit. Conclusion: The electrophysiologic method of measuring dysphagia limit conf irms neurogenic dysphagia and its severity in the neutral head position. Ch anges in head and neck positions do not significantly alter dysphagia limit in unimpaired subjects except for the chin-up position. Although the resul ts obtained were not compared with other techniques (eg, videofluoroscopy), this simple electrophysiologic method for describing dysphagia limit may h ave a place in the evaluation of dysphagia and its variability in various h ead and neck positions.