The effect of slow speech on tongue movements & acoustic vowel space distance in speakers with Amyotrophic Lateral Sclerosis
Abstract
With disease progression, the speech of talkers with Amyotrophic Lateral Sclerosis
(ALS) becomes increasingly imprecise and unintelligible. Although speaking rate reduction is
commonly used as a treatment approach to enhance speech intelligibility in these talkers, its
effect on tongue movements and speech acoustics is not well understood. Thus, the purpose of
this study was to determine how slow speech affects tongue excursions and speech acoustics in
persons with ALS. Further, this study investigated how tongue excursions and speech acoustics
differed between persons with ALS and healthy controls. Lastly, this study sought to determine
how predictable tongue excursions are based on speech acoustics in persons with ALS.
3D electromagnetic articulography was used to capture tongue movements during speech
in five talkers with ALS and five healthy controls. Tongue excursions and the vowel space
distance during the production of the vowels /a/ and /i/ in the word "kite" embedded in the
sentence "See a kite again" were measured during typical and slow speech.
Results showed increased tongue excursions and acoustic vowel space in response to
slow speech for persons with ALS and controls; however, the effect was larger in the control
group than in the ALS group. These outcomes support the current clinical assumption that slow
speech increases tongue excursions and expanded vowel space in persons with speech
impairments due to ALS. Although tongue excursions tended to be slightly larger in persons
with ALS than controls, vowel space tended to be smaller in persons with ALS than controls.
These findings challenged the current assumption that a small vowel space indicate small tongue
excursion. The predictability of change in tongue excursions based on change in speech acoustics
in response to slow speech was much lower in persons with ALS than controls. Thus, acoustic
measures should not be used to infer the underlying speech movements in persons with ALS.
Description
Thesis (M.A.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders
Collections
- CSD Theses and Dissertations [43]
- CHP Theses and Dissertations [46]
- Master's Theses [1437]