Spectral Aggregate of the High-Passed Fundamental Frequency and Its Relationship to the Primary Acoustic Features of Adductor Laryngeal Dystonia.

Abstract

Currently, no clinically feasible objective measures exist that are specific to the signs of adductor laryngeal dystonia (LD), deterring effective diagnosis and treatment. This project sought to establish concurrent validity of a new automated acoustic outcome measure, designed to be specific to adductor laryngeal dystonia (AdLD): the spectral aggregate of the high-passed fundamental frequency contour (SAHf o). Twenty speakers with AdLD read voiced phoneme-loaded (more symptomatic) and voiceless phoneme-loaded (less symptomatic) sentences. LD discontinuities (defined as phonatory breaks, frequency shifts, and creak), the acoustic ramifications of laryngeal spasms, were manually identified. The frequency content of the f o contour was examined as a function of time, and content above 1000 Hz was summed to automatically calculate SAHf o. Multiple linear regression analysis was applied to SAHf o based on LD discontinuities and sentence type (voiced or voiceless phoneme-loaded). The regression model accounted for 41.1% of the variance in SAHf o. Both the LD discontinuities and sentence type were statistically related to SAHf o. Results of this study provide evidence of concurrent validity. SAHf o is an automatic outcome measure specific to acoustic signs of AdLD that may be useful to track treatment progress.