Search

Purpose: The goal of this study was to determine the relationship between the perceptual measure of speech naturalness and objective measures of pitch, loudness, and rate control as a potential tool for assessment of ataxic dysarthria. Method: Twenty-seven participants with ataxia and 29 age- and sex-matched control participants completed the pitch glide and loudness step tasks drawn from the Frenchay Dysarthria Assessment-Second Edition (FDA-2) in addition to speech diadochokinetic (DDK) tasks. First, group differences were compared for pitch variability in the pitch glide task, loudness variability in the loudness step task, and syllable duration and speech rate in the DDK task. Then, these acoustic measures were compared with previously collected ratings of speech naturalness by speech-language pathology graduate students. Results: Robust group differences were measured for pitch variability and both DDK syllable duration and speech rate, indicating that the ataxia group had greater pitch variability, longer DDK syllable duration, and slower DDK speech rate than the control group. No group differences were measured for loudness variability. There were robust relationships between speech naturalness and pitch variability, DDK syllable duration, and DDK speech rate, but not for loudness variability. Conclusions: Objective acoustic measures of pitch variability in the FDA-2 pitch glide task and syllable duration and speech rate in the DDK task can be used to validate perceptual measures of speech naturalness. Overall, speechlanguage pathologists can incorporate both perceptual measures of speech naturalness and acoustic measures of pitch variability and DDK performance for a comprehensive evaluation of ataxic dysarthria. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we investigated how the direction and timing of a perturbation in voice pitch auditory feedback during phrasal production modulated the magnitude and latency of the pitch-shift reflex as well as the scaling of acoustic production of anticipatory intonation targets for phrasal prominence and boundary. Method: Brief pitch auditory feedback perturbations (±200 cents for 200-ms duration) were applied during the production of a target phrase on the first or the second word of the phrase. To replicate previous work, we first measured the magnitude and latency of the pitch-shift reflex as a function of the direction and timing of the perturbation within the phrase. As a novel approach, we also measured the adjustment in the production of the phrase-final prominent word as a function of perturbation direction and timing by extracting the acoustic correlates of pitch, loudness, and duration. Results: The pitch-shift reflex was greater in magnitude after perturbations on the first word of the phrase, replicating the results from Mandarin speakers in an American English-speaking population. Additionally, the production of the phrase-final prominent word was acoustically enhanced (lengthened vowel duration and increased intensity and fundamental frequency) after perturbations earlier in the phrase, but more so after perturbations on the first word in the phrase. Conclusion: The timing of the pitch perturbation within the phrase modulated both the magnitude of the pitch-shift reflex and the production of the prominent word, supporting our hypothesis that speakers use auditory feedback to correct for immediate production errors and to scale anticipatory intonation targets during phrasal production.

Purpose: This case study measured how well the Lee Silverman Voice Treatment (LSVT) improved vocal features, intelligibility, and communicative effectiveness for a multilingual participant with hypokinetic-hyperkinetic dysarthria secondary to suspected progressive supranuclear palsy. LSVT treatment was chosen for the participant due to the strengths and deficits he presented with prior to treatment, and for the anticipated challenges in treatment that may arise from the presence of multilingualism and impaired cognitive functioning. Methods: A multilingual patient in their 60's (English, Spanish, and French) with hypokinetic-hyperkinetic dysarthria secondary to suspected progressive supranuclear palsy completed the standard treatment sessions for LSVT. Assessment measures were taken at baseline, immediately post-treatment, and three-months post-treatment. Results: Improvementswere measured in vocal quality, vocal loudness, intelligibility, and communicative effectiveness immediately post-treatment. Three months posttreatment, improvements in vocal quality and intelligibility were maintained. Conclusion: This case study illustrates that LSVT may be a beneficial treatment for complex clients who are multilingual and present with complex comorbidities and cognitive deficits. LSVT resulted in some meaningful changes in vocal quality, intelligibility, and communicative effectiveness for this individual. Clinicians who work with complex patients may wish to consider the theoretical underpinnings of LSVT, client profile, areas of client need, and ability and desire to complete an intensive treatment program to determine if trialing LSVT is appropriate. The use of LSVT with complex clients may yield positive outcomes. [ABSTRACT FROM AUTHOR]

Purpose: Stuttering involves a breakdown in the speech motor system. We address whether stuttering in its early stage is specific to the speech motor system or whether its impact is observable across motor systems. Method: As an extension of Olander, Smith, and Zelaznik (2010), we measured bimanual motor timing performance in 115 children: 70 children who stutter (CWS) and 45 children who do not stutter (CWNS). The children repeated the clapping task yearly for up to 5 years. We used a synchronization-continuation rhythmic timing paradigm. Two analyses were completed: a cross-sectional analysis of data from the children in the initial year of the study (ages 4;0 [years;months] to 5;11) compared clapping performance between CWS and CWNS. A second, multiyear analysis assessed clapping behavior across the ages 3;5-9;5 to examine any potential relationship between clapping performance and eventual persistence or recovery of stuttering. Results: Preschool CWS were not different from CWNS on rates of clapping or variability in interclap interval. In addition, no relationship was found between bimanual motor timing performance and eventual persistence in or recovery from stuttering. The disparity between the present findings for preschoolers and those of Olander et al. (2010) most likely arises from the smaller sample size used in the earlier study. Conclusion: From the current findings, on the basis of data from relatively large samples of stuttering and nonstuttering children tested over multiple years, we conclude that a bimanual motor timing deficit is not a core feature of early developmental stuttering.

A study was conducted to examine production variability in American Sign Language (ASL) in order to gain insight into the development of motor control in a language produced in another modality. Production variability was characterized through the spatiotemporal index (STI), which represents production stability in whole utterances and is a function of variability in effector displacement waveforms (Smith et al., 1995). Motion capture apparatus was used to acquire wrist displacement data across a set of eight target signs embedded in carrier phrases. The STI values of Deaf signers and hearing learners at three different ASL experience levels were compared to determine whether production stability varied as a function of time spent acquiring ASL. We hypothesized that lower production stability as indexed by the STI would be evident for beginning ASL learners, indicating greater production variability, with variability decreasing as ASL language experience increased. As predicted, Deaf signers showed significantly lower STI values than the hearing learners, suggesting that stability of production is indeed characteristic of increased ASL use. The linear trend across experience levels of hearing learners was not statistically significant in all spatial dimensions, indicating that improvement in production stability across relatively short time scales was weak. This novel approach to characterizing production stability in ASL utterances has relevance for the identification of sign production disorders and for assessing L2 acquisition of sign languages.

This study investigated the effect of semantic focus on pitch auditory feedback control in the production of phrasal prosody through an experiment using pitch-shifted auditory feedback. We hypothesized that pitch-shift responses would be mediated by semantic focus because highly informative focus types, such as corrective focus, impose more specific constraints on the prosodic form of a phrase and require greater consistency in the production of pitch excursions compared to sentences with no such focus elements. Twenty-eight participants produced sentences with and without corrective focus while their auditory feedback was briefly and unexpectedly perturbed in pitch by +/−200 cents at the start of the sentence. The magnitude and latency of the reflexive pitch-shift responses were measured as a reflection of auditory feedback control. Our results matched our prediction that corrective focus would elicit larger pitch-shift responses, supporting our hypothesis that auditory feedback control is mediated by semantic focus. [ABSTRACT FROM AUTHOR]