A kinematic analysis of articulatory function in dysarthric and non-dysarthric speakers with Parkinson’s disease

Min Wong (2011). A kinematic analysis of articulatory function in dysarthric and non-dysarthric speakers with Parkinson’s disease PhD Thesis, School of Health & Rehabilitation Sciences, The University of Queensland.

       
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Author Min Wong
Thesis Title A kinematic analysis of articulatory function in dysarthric and non-dysarthric speakers with Parkinson’s disease
School, Centre or Institute School of Health & Rehabilitation Sciences
Institution The University of Queensland
Publication date 2011-12
Thesis type PhD Thesis
Supervisor Professor Bruce E. Murdoch
Dr. Brooke-Mai Whelan
Total pages 239
Total black and white pages 239
Language eng
Subjects 11 Medical and Health Sciences
Abstract/Summary The most common articulatory impairment reported in individuals with Parkinson’s disease (PD) is imprecision of consonant production, although, it is noted that depending on the level of severity of PD, articulation of vowels may be affected. It has been hypothesised that the imprecision of consonant production is the result of limited range of movement, slowness of movement, muscle rigidity and reduced force of movement of the articulators. To date, the majority of research has utilised descriptive analysis, acoustical techniques and non-speech physiological measures in the investigation of articulatory function in individuals with PD. The application of dynamic investigation, specifically electromagnetic articulography (EMA) is limited. In an attempt to add empirical data to the body of research, the present thesis aims to use EMA to investigate tongue function in dysarthric and non-dysarthric speakers with PD during sentence production and rapid syllable repetition. Additionally, the present thesis also aims to explore the effects of increased loudness on tongue function in dysarthric speakers with PD. A total of 15 individuals with PD participated in this research. The participants were further divided into two groups, dysarthric speakers with PD (n = 8) and non-dysarthric speakers with PD (n = 7) based on the findings of perceptual speech evaluation. A total of 11 neurologically healthy participants also participated in the study to serve as normal controls. EMA was used to examine the tongue tip and tongue back movements during sentence production and rapid syllable repetition. The lingual kinematic parameters examined included maximum velocity, maximum acceleration, maximum deceleration, duration and distance of tongue movement. In Chapter 2, the lingual kinematics in a group of seven non-dysarthric speakers with PD were examined using EMA, matched with seven normal controls. The tongue tip and tongue back movements were examined during the production of an alveolar sentence Tess told Dan to stay fit and a velar sentence Karl got a croaking frog, respectively. The subclinical lingual kinematic deficits documented in the non-dysarthric speakers with PD included significantly prolonged duration of lingual movement, significant slower rate of sentence production and reduced speed measures (i.e., maximum velocity, maximum acceleration/deceleration) of lingual movement. However, no significant differences in the distance/range of lingual movement were reported. In Chapter 3, the lingual kinematics during alveolar and velar sentence production in a group of eight mild dysarthric speakers with PD were examined, and matched with eight normal controls. During alveolar consonant production, the dysarthric speakers with PD had similar range but prolonged duration of lingual movement; during velar consonant production, the dysarthric speakers with PD had increased range but similar duration of lingual movement. The dysarthric speakers with PD also had increased speed measures of lingual movement primarily in the release phase of consonant production. Having examined the lingual kinematics in dysarthric speakers with PD (DPD) and non-dysarthric speakers with PD (NDPD) separately, a between groups comparison was essential to determine the factors that may contribute to dysarthria in PD. Hence, Chapter 4 compared lingual kinematics in the DPD group, the NDPD group and a group of 11 normal controls during alveolar and velar sentence production. Results showed that both the DPD and NDPD groups had deviant articulatory movement during consonant production that resulted in longer duration of consonant production. When compared to the NDPD group, the DPD group primarily had increased range of lingual movement together with increased speed measures of lingual movement that resulted in comparable duration of lingual movement. The lingual kinematics in a subgroup of five DPD and five NDPD were further explored in Chapter 5 by examining the tongue tip and tongue back movements during rapid /ta/ and /ka/ syllable repetition. The results showed that although the DPD, the NDPD and the normal control groups had comparable rapid syllable repetition rates, significant between groups differences were documented for most of the kinematic parameters. Chapter 6 sought to examine, in detail, the tongue tip kinematics of two dysarthric participants with PD during habitual and loud alveolar sentence production as well as rapid /ta/ syllable repetition. Results showed that the two participants with PD exhibited lingual kinematic deficits in all three speaking conditions with marked individual differences. Positive effects of increased loudness on lingual kinematics were also documented. Overall, the findings of the present thesis are contrary to proposed theories that suggest that the clinical features of hypokinetic dysarthria in PD, including articulatory imprecision, is the outcome of reduced range of articulatory movement. The prolonged duration of lingual movement may plausibly be due to the increased range of lingual movement rather than slowness of lingual movement. Further, increased loudness may contribute to increased tongue function in individuals with PD. The noticeable individual variability documented has important clinical implications. This thesis provides the largest kinematic study of lingual function in individuals with PD using EMA to date. It is anticipated that this research will provide a baseline for further longitudinal study of articulatory function in individuals with PD.
Keyword Parkinson's disease
Dysarthria
Articulation
Electromagnetic Articulography
Tongue
Additional Notes Landscape pages: 72-73, 94-97, 144-147, 170-171, 175

 
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