Automated Creak Detection in Spanish Speakers with and without AdLD

Adductor laryngeal dystonia (AdLD) is a neurological voice disorder characterized by involuntary spasms of the adductor laryngeal muscles during phonation. An automated creak detector has shown promise in differentiating English speakers with AdLD from controls. However, no study has yet investigated creak in AdLD in Spanish speakers. In fact, there is a paucity of research validating tools to identify laryngeal dystonia (LD) in languages other than English. The purpose of this study was to determine whether creak differentiates Spanish-speaking individuals with and without AdLD.

Twenty speakers with AdLD, twenty speakers without voice disorders (controls), and twenty speakers with glottic insufficiency were recorded in a clinical environment. Each participant read a set of recently developed Spanish stimuli designed for LD screening, containing voiced and voiceless loaded sentences. An open-source creak detector was used to calculate the percentage of creak in each speaker's recording. Mean smoothed cepstral peak prominence (CPPS) per speaker was calculated in Praat.

A Pearson's correlation revealed a moderate relationship between creak and CPPS across groups (r = -0.56). An analysis of covariance revealed a statistically significant effect of creak between groups (F(3, 56) = 13.52, P > 0.05, R² = 0.39). Three receiver operating characteristic curve analyses indicated that creak differentiated AdLD and Controls (area under the curve [AUC] = 0.88), as well as AdLD and Glottic Insufficiency with acceptable diagnostic accuracy (AUC = 0.73), but not between control or glottic insufficiency groups.

Creak differentiated Spanish speakers with and without AdLD with moderate discrimination. Although creak and CPPS were moderately correlated, when controlling for CPPS, creak was statistically different between speakers with AdLD and speakers with glottic insufficiency, and between speakers with AdLD and controls. Further work is needed to determine the clinical utility of creak in aiding a differential diagnosis of AdLD and muscle tension dysphonia in Spanish-speaking individuals.