A Multidimensional Study on Articulation Deficits in Parkinsons Disease

Study Overview
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Brief Summary
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Articulatory deficits are present in most speakers with dysarthria, which negatively impacts their speech intelligibility, yet little is known about the relationship between articulatory movement and speech intelligibility. This study will examine the relationship between articulation measures, both acoustic and kinematic, and their relationship to perceptual measures (i.e., speech intelligibility and articulation ratings) in 30 individuals with dysarthria secondary to Parkinson's disease and 30 neurologically healthy adults of the same age. The findings will have implications for behavioral management.

Detailed Description
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Dysarthria is a motor speech disorder that affects individuals with various etiologies. Parkinson's disease (PD) alone affects nearly one million individuals in the U.S., with dysarthria developing in approximately 90% of these individuals within the first two years of onset. The dysarthria associated with PD is characterized by reduced movement, which has been supported by findings of reduced lip, tongue, and jaw movement in speakers with PD. However, it remains unclear if hypokinetic dysarthria causes a global reduction across all articulators, or if specific articulators are disproportionally affected by the disease. Further, it is not fully understood what factors contribute to speech intelligibility. Specifically, little is known about the articulatory-kinematic correlates of speech intelligibility. This missing link is vital to understand, as articulation deficits are a universal characteristic of dysarthria, regardless of etiology. The proposed study provides a linked investigation of kinematic, acoustic, and perceptual characteristics in speakers with PD and neurologically healthy speakers. This research aims to (1) examine the perceptual, acoustic, and articulator-specific movement deficits in speakers with PD and (2) understand the relationship between articulatory movement and measures of speech perception. Specific Aim 1 will examine the group differences between speakers with PD and neurologically healthy speakers using perceptual, acoustic, and articulator-specific kinematic measures. The investigators hypothesize the perceptual, acoustic, and tongue-related kinematic measures will differentiate individuals with PD from neurologically healthy speakers. Specific Aim 2 will model speech intelligibility (Specific Aim 2a) and ratings of articulatory precision (Specific Aim 2b) using selected acoustic and kinematic measurements. The investigators hypothesize that the acoustic measures will be stronger predictors of speech intelligibility than the kinematic measures, as they are both derived from the speech signal. Further, the investigators hypothesize the selected kinematic measures may demonstrate a stronger relationship to articulation ratings than speech intelligibility. This study is a requisite step toward our long-term goal of advancing dysarthria management strategies. The primary outcome will be explanatory models that identify acoustic and articulatory correlates of speech intelligibility and articulatory precision. This study has important implications for developing articulator-specific dysarthria management strategies to supplement universal dysarthria management strategies.

Official Title
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A Multidimensional Study on Articulation Deficits in Parkinson's Disease

Conditions
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Parkinson Disease, Dysarthria, Hypokinetic

Intervention / Treatment
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* Behavioral: Clear Speech
* Behavioral: Less Clear Speech


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: neurological diagnosis of PD (for the PD group only) diagnosis of dysarthria (for the PD group only) native English speaker no evidence of cognitive impairment, as indicated by a score above 26 on the Montreal Cognitive Assessment able to read a paragraph in 19-point font Exclusion Criteria: Not within the age limits

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Parkinsons (PD) Group<br>This cohort includes individuals who have been diagnosed with Parkinson's disease. | Behavioral: Clear Speech<br>* This behavioral modification asks participants to speak more clearly, as if they were speaking to someone with a hearing loss.<br>Behavioral: Less Clear Speech<br>* This behavioral modification asks participants to speak less clearly, as if they were in a room with many people and they were mumbling something to the person next to them that they didn't want other people in the room to hear.<br>|
| Neurotypical (NT) Group<br>This group consists of age-matched control participants. They are neurologically healthy and do not have any neurological diagnoses. | Behavioral: Clear Speech<br>* This behavioral modification asks participants to speak more clearly, as if they were speaking to someone with a hearing loss.<br>Behavioral: Less Clear Speech<br>* This behavioral modification asks participants to speak less clearly, as if they were in a room with many people and they were mumbling something to the person next to them that they didn't want other people in the room to hear.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vowel Space Area | Vowel space area is a measure of the planar area among the four corner vowels /i/, /ae/, /a/, and /u/. It is calculated using the first and second formant resonant frequencies obtained from the acoustic signal, using the software PRAAT. | Baseline | 
| F2 Slope | Second formant frequency (F2) slope is measured as the rate of F2 change during the diphthong in Buy. To calculate this measure, first the investigators will obtain the extent of F2 change (max F2 - min F2) from the diphthong Buy. Then this F2 change is divided by the duration of the diphthong Buy. | Baseline | 
| Tongue and Jaw Speed | This is measured as the tongue and jaw speed during the diphthong in Buy. Specifically, this will be calculated as tongue/jaw movement (measured in mm), divided by movement duration (measured in ms). The tongue and jaw movement will be collected using the electromagnetic articulography (EMA) device used in this study. | Baseline | 
| Acoustic Distance | This is measured as the Euclidean distance between the second formant frequency (F2) onset and offset of the diphthong in Buy in an F1-F2 (first and second formant frequency) space. Measured in Hz. | Baseline | 
| Tongue and Jaw Distance | This is measured as the Euclidean distance between the tongue and jaw onset and offset of the diphthong in Buy in a two-dimensional space.The tongue and jaw movement will be collected using the electromagnetic articulography (EMA) device used in this study. | Baseline |