Abstract
Purpose: To compare two different tasks and kinematic measures in terms of their ability to detect Amyotrophic lateral sclerosis (ALS) and differences in ALS severity in order to establish potential candidate markers of bulbar decline.Method: We tracked jaw kinematics during speech and chewing to determine which is more affected by bulbar motor deterioration, based on measures of maximum speed and articulatory working space. Data were collected from 31 individuals diagnosed with ALS and 17 neurologically intact controls.Result: (1) Both sentence and chewing tasks were effective in distinguishing between the groups of individuals with ALS and controls, (2) jaw maximum speed for both chewing and speech was a more sensitive marker for bulbar dysfunction than articulatory working space, (3) the sentence task distinguished between ALS subgroups stratified by severity and (4) distinct jaw kinematic differences existed between chewing and sentence tasks. More specifically, movement speed for speech decreased with severity while movement speed for chewing increased with disease severity.Conclusion: The findings from the current investigation suggest that measures of jaw movement speed during chewing and sentence tasks are affected by bulbar deterioration, and jaw speed during a sentence task may serve as a candidate marker of bulbar disease onset and severity.