Position of the hyoid and larynx in people with muscle tension dysphonia.

OBJECTIVES/HYPOTHESIS To determine whether radiographic measures of hyoid position, laryngeal position, and hyolaryngeal space during phonation were different for people with primary muscle tension dysphonia (MTD) as compared to control participants without voice disorders. STUDY DESIGN Prospective, quasi-experimental research design. METHODS Twenty participants, 10 with primary MTD and 10 without voice disorders who were age and sex matched were studied radiographically while producing phonation. Lateral x-ray images were obtained for each participant during three tasks: resting state, sustained phonation, and a swallow-hold maneuver. Vertical positions of the hyoid and larynx were measured on a Cartesian coordinate system and were normalized to reflect change from rest during phonation. RESULTS Normalized, vertical hyoid, and laryngeal positions during phonation were significantly higher for people with MTD than for control participants. Normalized hyolaryngeal space during phonation did not show differences between groups. A low to moderate significant correlation for radiographically measured hyoid and laryngeal position and the total score from a subjective laryngeal palpatory scale were evidenced, but no relationship was evidenced for radiographic laryngeal position and the laryngeal position subscore of the palpatory examination. CONCLUSIONS Objective determinants of physiology are critical for the differential diagnosis of MTD and its effective treatment. Radiographic findings from this study indicate that hyoid and laryngeal positions during phonation are higher in people with primary MTD as compared to people without voice disorders.