Vocal changes across disease progression in amyotrophic lateral sclerosis (ALS)

Abstract

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by loss of muscle strength and function. The speech systems (respiratory, phonatory, velopharyngeal, and articulatory) are frequently affected, causing speech and swallowing impairments. Changes to voice production are often reported. These changes include altered fundamental frequency, phonatory instability, and the development of breathy or harsh voice quality (see Green et al., 2013 for review). While acoustic studies of speakers with ALS have demonstrated voice dysfunction, the findings have been variable in the type and direction of change across individual speakers. The current investigation seeks to further explicate vocal dysfunction and change in ALS by exploring promising acoustic phonatory measures across disease progression. Participants with and without ALS were audiorecorded at multiple time points while producing sustained vowels and connected speech. Acoustic analyses include traditional phonatory measures extracted from vowel prolongations (fundamental frequency, jitter, and shimmer) and newer measures of phonation across connected speech (e.g., cepstral peak prominence). Voice metrics are compared between speaker groups and across time points. It is anticipated that the findings will support the development of valid and reliable measures to mark disease onset and progression, thereby facilitating intervention and mitigating the devastating impact of ALS.Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by loss of muscle strength and function. The speech systems (respiratory, phonatory, velopharyngeal, and articulatory) are frequently affected, causing speech and swallowing impairments. Changes to voice production are often reported. These changes include altered fundamental frequency, phonatory instability, and the development of breathy or harsh voice quality (see Green et al., 2013 for review). While acoustic studies of speakers with ALS have demonstrated voice dysfunction, the findings have been variable in the type and direction of change across individual speakers. The current investigation seeks to further explicate vocal dysfunction and change in ALS by exploring promising acoustic phonatory measures across disease progression. Participants with and without ALS were audiorecorded at multiple time points while producing sustained vowels and connected speech. Acoustic analyses include traditional phonatory measures ext...