Based on previous acoustic studies, people with dysarthria secondary to amyotrophic lateral sclerosis (PALS) experience different degrees of difficulty in producing vowels; therefore, some vowels may be harder to produce than others. The current study aims to identify as to why there are vowel-specific production difficulties by looking at the articulatory underpinnings of both the tongue and jaw. The participants included twenty-two PALS and twenty-two sex- and age-matched controls. The target stimuli were nine monophthongs in American English that were placed in a /h/-vowel-/d/ context in a carrier phrase. To record the tongue and jaw movements of each participant, an electromagnetic articulography was used. The results of the current study showed that there are three characteristics of vowels that show clear kinematic differences between PALS and typically aging individuals, such as 1. Being a high or mid-high vowel, 2. Requiring the greatest amount of tongue movement as seen in typically aging individuals, and 3. Requiring the least amount of movement as seen in typically aging individuals. This vowel-specific pattern was observed in tongue kinematic variables but was not seen in jaw kinematic variables.
