The goal of this study is to evaluate the efficacy of voice therapy for neurogenic voice disorders. The main questions are: Does voice therapy improve patient-reported quality of life in speakers with neurogenic voice disorders? Does voice therapy improve listener perception of voice in speakers with neurogenic voice disorders? Does voice therapy improve acoustical analyses of voice in speakers with neurogenic voice disorders? Does voice therapy improve physiologic function in speakers with neurogenic voice disorders?
Neurogenic voice disorders negatively impact communication-related quality of life for millions of patients. Yet current options for medical treatment including pharmacological and surgical interventions do not consistently improve voice and can have adverse effects. Although some patients with neurogenic voice disorders receive behavioral treatment like voice therapy, systematic treatment research evaluating the efficacy of behavioral treatment is limited. For example, in speakers with voice disorders related to essential tremor, the most common movement disorder in the world, only five studies have evaluated the effects of behavioral interventions. Of these studies, two were case studies (N=1, N=2), two were single-case experiments (N=1, N=3), and one was a prospective group study comparing control and experimental conditions (N=10). These studies evaluated a variety of treatment ingredients using various functional, perceptual, and acoustical treatment outcomes. However, some treatment ingredients and outcome measures were not specific to the underlying voice impairments in essential tremor. In neurogenic voice disorders with other etiologies like dystonia, more studies with larger sample sizes have been conducted. However, only eight studies have been published: two were case studies (N=1, N=1), one was a single-case experiment (N=1), one was a prospective group study comparing pre- and post-treatment phases (N=36), one was a retrospective group study comparing control and experimental conditions (N=37), one was a randomized cross-over study (N=9), one was a non-randomized controlled trial (N=17), and one was a randomized controlled trial (N=31). These studies also evaluated various treatment ingredients using functional, perceptual, and acoustical outcomes, as well as aerodynamic and acoustic outcomes. But again, some treatment ingredients and outcome measures were not specific to the underlying voice impairments related to dystonia. Finally, although a considerably higher number of treatment studies with greater sample sizes have been conducted with speakers who have voice disorders related to Parkinson's disease, the most widely studied treatment ingredients have limitations. For example, Lee Silverman Voice Therapy requires high-intensity, high-frequency treatment provided by speech-language pathologists with specialized training, and expiratory muscle strength training is also high-frequency, high-intensity treatment that requires specific equipment and physiologic capabilities. Thus, there is an important need for systematic treatment research in speakers with neurogenic voice disorders using treatment ingredients and outcome measures that are specific to patients' neurophysiologic impairments and functional limitations.
Participants will be trained to produce a breathy voice to reduce the perceptual severity of vocal tremor
The University of Texas at Austin
Austin, Texas, United States
Patient-reported outcome measures
Participants will be asked to rate their perception of the voice strategy on a 6-point Likert scale (0 = not at all, 5 = very much): 1) My voice was shaky when I used the strategy, 2) It was effortful to speak when I used the strategy, 3) It was difficult to use the strategy, 4), I liked the sound of my voice when I used the strategy.
Time frame: Participants will complete ratings during the treatment phase at the beginning of the first treatment session and at the end of the last treatment session.
Auditory-perceptual ratings
Listeners will be asked to complete perceptual ratings for the participants' voices by marking the severity of the 'shakiness' on a visual-analog scale (0 = not shaky, 100 = very shaky).
Time frame: Listeners will rate samples from all study phases within two years after all data have been collected from all study participants.
Acoustical analyses - extent of modulation
The extent of fundamental frequency and intensity modulation in percent will be measured in participants' sustained vowels as an estimate of tremor magnitude.
Time frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
Acoustical analyses - modulation rate
The rate of fundamental frequency and intensity modulation in Hertz will be measured in participants' sustained vowels as an estimate of tremor speed.
Time frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
Acoustical analyses - cepstral peak prominence
The cepstral peak prominence will be measured in participants' sustained vowels and connected speech as an estimate of 'breathiness.'
Time frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
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Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
40
Acoustical analyses - voice breaks
The number and duration of voice breaks will be measured in participants' sustained vowels.
Time frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.