Supraglottic Laryngeal Maneuvers in Adductor Laryngeal Dystonia During Connected Speech

Adductor laryngeal dystonia (AdLD) disrupts fine motor movements of vocal folds during speech, resulting in a strained, broken, and strangled voice. Laryngeal high-speed videoendoscopy (HSV) in connected speech enables the direct visualization of detailed laryngeal dynamics, hence, it can be effectively used to study AdLD. The current study utilizes HSV to investigate supraglottic laryngeal tissue maneuvers obstructing the view of the vocal folds, in AdLD and normophonic speakers during connected speech. Characterizing the laryngeal maneuvers in these groups can facilitate a deeper understanding of the normophonic voice physiology and AdLD voice pathophysiology.

HSV data were obtained from six normophonic speakers and six patients with AdLD during production of connected speech. Three experienced raters visually analyzed the data to determine laryngeal tissues leading to obstructions of vocal folds in HSV images. The raters recorded the duration of each obstruction and indicated the specific tissue(s) leading to the obstruction. After the completion of their individual visual analysis, the raters came to consensus about their observations and measurements.

Statistical analysis indicated that AdLD patients exhibited higher occurrences of vocal fold obstructions and longer durations of obstructions compared with the normophonic group. Similar obstruction types were found in both groups, with the epiglottis being the primary site of obstruction for both. Participants with AdLD displayed significantly elevated occurrences of sphincteric compression resulting in vocal fold obstruction.

HSV can be used to study the movements of laryngeal tissues in detail during connected speech. The analysis of supraglottic laryngeal tissue dynamics in speech can help us characterize the AdLD pathophysiology. The study's findings regarding the tissues implicated in obstructions may potentially inform the development of patient-specific therapeutic strategies targeting individual control over specific laryngeal muscles during phonation and speech production.