Speech

Permanent URI for this collectionhttps://digital.lib.washington.edu/handle/1773/4970

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Asian Indian Families' Experiences with Autism, Neurodiversity, and Language Intervention in the United States
(2026-04-20) Ram, Poornima; Kover, Sara
Autism research in the field of communication science disorders (CSD) has insufficient representation of cultural perspectives. Research through an intersectionality lens can better inform training, practice and policies for CSD, specifically in the U.S., where families seeking SLP services represent a wide range of racial and cultural identities. Using a qualitative methodology, this dissertation explored the lived experiences of Asian Indian families with autistic children to gain insight into cultural and linguistic factors that may influence how these families approach and engage with speech-language therapy services, and how cultural contexts shape their understanding of the concepts of disability, autism, and neurodiversity-affirming care. Fourteen mothers and two fathers from six states across the U.S. participated in the study. Participant accounts were captured through semi-structured interviews. Three broad themes were identified: dissatisfaction with SLP services; the stigma of autism; and cultural factors can be both barriers and supports. Implications and recommendations for practice, training and research are provided.
Examining Cortical and Subcortical Processes Underlying Speech Auditory-motor Adaptation and Syllable Sequence Learning
(2025-10-02) Wang, Hantao; Max, Ludo
Sensorimotor control and learning rely on the dynamic interplay of cortical-subcortical circuits, particularly the cerebellum and basal ganglia. Beyond their roles in feedforward and feedback control, these cortical-subcortical circuits are implicated in distinct motor learning mechanisms, including sensory prediction error-based learning, reinforcement learning, strategy-based learning, and motor sequence learning. While most knowledge about cortico-subcortical contributions to motor control comes from studies of non-speech movements, similar mechanisms are thought to underlie speech sensorimotor control and learning. Disorders affecting these structures, such as Parkinson's disease (PD), essential tremor (ET), and cerebellar degeneration, are associated with motor speech impairments, altered speech sensorimotor control, and deficits in speech motor learning. This dissertation integrates behavioral, neurostimulation, and neurophysiological evidence to investigate the cortical and subcortical processes underlying two fundamental forms of speech motor learning: auditory–motor adaptation and syllable sequence learning. Chapter I reviews the literature on speech sensorimotor control in basal ganglia and cerebellar disorders, focusing on motor and sensory impairments, performance in auditory perturbation tasks, and the modulatory effects of pharmacological and deep brain stimulation (DBS) interventions. The review highlights both converging and divergent findings across patient populations and underscores key knowledge gaps. Chapter II presents a behavioral study testing the effects of basal ganglia DBS in PD and cerebellar-related DBS in ET on auditory-motor adaptation and syllable sequence learning. Results showed that these learning processes are differentially affected in PD and ET, but they are not acutely modulated by DBS. ET patients exhibited reduced early adaptation under gradual perturbations and lower overall sequence accuracy, whereas PD patients performed comparably to controls in both domains. Chapter III investigates subthalamic nucleus (STN) electrophysiology during speech production in PD patients using subcortical recordings from implanted DBS electrodes. STN activity showed beta event-related desynchronization/re-synchronization (ERD/ERS) during speech, attenuated under stimulation and modulated by sequence complexity, but unrelated to auditory-motor adaptation, suggesting a role for the STN in speech sequencing. Finally, Chapter IV employs electroencephalography in healthy adults to compare oscillatory dynamics of auditory-motor adaptation and syllable sequence learning. Both tasks elicited alpha/beta ERD during speech planning, but only sequence learning showed stronger alpha ERD in early versus late trials, identifying alpha desynchronization as a potential neural marker of syllable sequence learning. Together, these studies delineate complementary roles of cerebello-thalamo-cortical and basal ganglia-thalamo-cortical circuits in speech sensorimotor learning, clarify how neurological disorders and DBS shape these processes, and identify oscillatory markers that distinguish distinct forms of speech sensorimotor learning.
International Students' Belongingness in U.S. Communication Sciences and Disorders Clinical Graduate Programs
(2025-10-02) Xu, Shiao; Kover, Sara
Communication sciences and disorders (CSD) encompasses speech-language pathology (SLP) and audiology, both of which are vital for addressing a range of communication and hearing disorders. Despite rigorous training and a heterogeneous patient population, the CSD workforce in the United States remains predominantly homogeneous and is not particularly well-prepared to serve individuals from culturally and linguistically diverse backgrounds. International students, although historically well-represented in U.S. higher education, make up a small fraction of the student bodies in clinical CSD graduate programs, suggesting potential barriers in these programs for students without U.S. citizenship. Applying Allen et al.'s (2021) framework of belonging, this study explored how competencies (e.g., cultural intelligence, language proficiency), opportunities (e.g., social connections), motivations (e.g., academic and professional aspirations), perceptions (e.g., faculty support, microaggressions), and sociocultural contexts (e.g., cultural distance) impact international students' sense of belonging in CSD programs using a mixed-methods survey approach. Participants included 43 international graduate students currently enrolled in entry-level clinical graduate programs in SLP and audiology or completing their clinical fellowship year in the U.S. Several predictors of belongingness were identified based on quantitative analyses: cultural intelligence, experiences of microaggressions, and faculty support. By identifying potential areas associated with belongingness that can be bolstered, these findings contribute to efforts to foster greater cultural and linguistic diversity within the CSD field and ultimately improve the quality of care for diverse patient populations both domestically and globally.
Familiarization to Speech in Noise: The Roles of Phonological Processing and Audiovisual Integration
(2025-10-02) Smith, Erin; Ingvalson, Erin
Phonological processing, or the ability to recognize and manipulate phonemes, is a key aspect of language comprehension. Accurate speech recognition relies on the listener's ability to rapidly decode phonemic information. It is known that audiovisual (AV) integration can facilitate the speech recognition process, where simultaneously presented visual cues of a speaker's articulators can calibrate perception of the acoustic characteristics of incoming speech signals. In typically developing listeners, speech recognition is more robust with AV stimulus integration compared to unimodal auditory presentation. However, it remains unclear whether AV integration similarly benefits speech recognition in listeners with poor phonological processing ability. The present study uses a high-level linguistic task to examine whether a listener's recognition of unfamiliar speech in noise is moderated by their phonological processing ability, given a familiarization passage with unimodal auditory or multimodal AV stimulus presentation. Results show that there was no benefit of passive AV exposure to the speaker for sentence recognition. Moreover, while phonological processing ability supports overall recognition of speech in noise, it did not moderate the amount of gain received by AV integration. These findings indicate that as a listener-specific factor, phonological processing does not impact the effect of AV integration for the perceptual learning of unfamiliar speech.
Advanced Insights into the Regenerative Limits, Molecular Identities, and Functional Necessity of Vestibular Hair Cell Subtypes in the Adult Mouse Vestibular System
(2025-10-02) Ciani, Amanda; Stone, Jennifer
Vestibular hair cells are specialized mechanosensory receptors in the inner ear that detect head movements and gravitational forces to support balance, gaze stabilization, and spatial orientation (Hudspeth, 1997; Corey & Hudspeth, 1983; Gillespie & Müller, 2009). In adult mammals, these cells are vulnerable to damage from aging, ototoxic drugs, and genetic mutations, and they have limited regenerative abilities (Forge et al., 1993; 1998; Kawamoto et al., 2009; Golub et al., 2012; Bucks et al., 2017; Sayyid et al. 2019; Hicks et al., 2020; Ciani Berlingeri et al., 2022; Jauregui et al. 2024) compared to those in non-mammalian vertebrates such as birds and fish (Corwin & Cotanche, 1988; Ryals & Rubel, 1988; Ma et al., 2008). It is likely that humans also have some capacity for hair cell regeneration (Taylor et al., 2018). This limited regenerative capacity contributes to persistent vestibular dysfunction and balance impairment following hair cell loss (Agrawal et al., 2009; Hicks et al., 2020). Although a few studies have shown partial recovery of function, the newly formed hair cells do not fully compensate for the loss of vestibular function (Schlecker et al., 2011; Sayyid et al., 2019; Bremer et al., 2014). Many questions arise from these previous results. Why are only some type II hair cells regenerated? What is needed for functional regeneration? These and many other questions drive my work into the adult vestibular system. In this thesis, I investigated the molecular, functional, and regenerative properties of vestibular hair cells in adult mice. Using a conditional knockout model, I show that the transcription factor SOX2, previously implicated in sensory development (Kiernan et al., 2005; Neves et al., 2012), is required in adult vestibular supporting cells for the limited regeneration of hair cells following hair cell loss. Sox2-deficient supporting cells failed to transdifferentiate into new hair cells, resulting in markedly reduced regeneration across the utricle, saccule, and ampulla (Ciani Berlingeri et al., 2022). Although we now know Sox2 and Atoh1 (Hicks et al., 2020) are necessary for the limited number of regenerated hair cells and that these cells come from supporting cells, the lack of regeneration of all the rest of the hair cells does not occur. This led to my exploration into the different types of cells in the adult vestibular sensory epithelia. Maybe there are more cell types than we think. To define the molecular identity of vestibular hair cell subtypes, I performed single-nucleus RNA-sequencing on adult mouse utricles. This transcriptomic profiling revealed five molecularly distinct hair cell subtypes spanning the classically defined type I and type II hair cell types across different epithelial zones. Markers such as Calb2, Spp1, Ocm, Agbl1, Paqr9, and others distinguished these subtypes (Xia et al., 2025; Desai et al., 2005; Simmons et al., 2010; Dechesne et al., 1988), and expression patterns were validated through immunolabeling and fluorescent in situ hybridization. The findings expand upon previous efforts by defining hair cell heterogeneity in the adult utricle at single-cell resolution and identifying novel molecular markers specific to regional and subtype identity through analysis of thousands of adult cells (McInturff et al., 2018, Xia et al., 2025). These molecular differences could result in functional differences. Therefore, while analyzing these cells molecularly, I also investigated the functional requirements of one population of vestibular hair cells. I employed a selective genetic ablation strategy to remove peripheral type I hair cells in all vestibular organs in adult mice while preserving central type I and all type II populations using a recently generated mouse line (McGovern et al., 2022; Hartman et al., 2018). This loss caused severe and lasting deficits in balance and vestibulo-ocular reflex performance, highlighting the unique and non-redundant role of peripheral type I hair cells in dynamic vestibular function. Altogether, this work identified Sox2 as a key regulator of supporting cell driven hair cell regeneration, revealed new molecular markers and subtype distinctions in adult vestibular hair cells, as well as identified the critical role of peripheral type I hair cells in maintaining complex vestibular reflexes. These findings add to the foundation for regenerative strategies aimed at restoring vestibular function after injury or degeneration.
Treatment of Ataxic Dysarthria Using a Modified Be Clear Approach: A Pilot Study
(2025-10-02) Olegario, Alliyah; Spencer, Kristie
Ataxic dysarthria is a motor speech disorder characterized by irregular articulatory errors as well as changes to prosody, such as atypical variability in loudness, pitch and stress (Duffy, 2020). Like many other motor speech disorders, ataxic dysarthria can impact an individual's quality of life, affecting social participation, well-being, and mental health (Daker-White et al., 2015; Jacobi et al., 2018). To date, treatment studies specifically designed for speakers with ataxic dysarthria have been limited. The present study examined the viability of a tailored speech treatment that builds on the established Be Clear (Park et al., 2016) and ClearSpeechTogether (Lowit et al., 2023) approaches. In this pilot study, two speakers with ataxic dysarthria participated in an 8-week treatment administered remotely. Strategies focused on overenunciation and slowed rate via phrasing. Ten listeners conducted blinded perceptual ratings of articulation clarity and speech naturalness across three time points (pre-treatment, immediately post-treatment, and 1-month maintenance). Outcome measures of transcription intelligibility and psychosocial impact were also included. Results suggest improvements across perceptual ratings of intelligibility and naturalness, as well as pronounced increases to sentence-level intelligibility. Post-treatment changes to measures of dysarthria impact and communication participation were mixed. Additional research is required to establish efficacy with a larger and more diverse sample.
The Effects of Age and Background Noise on Intelligibility and Perceived Listening Effort for Tracheoesophageal Speakers
(2025-10-02) Spies, Carly; Eadie, Tanya
The current study evaluated the effect of background noise and/or a communication partner's age on speech intelligibility and perceived listening effort for individuals who use tracheoesophageal (TEP) speech. Nine adult male TEP speakers provided speech samples from an intelligibility test. One set of speech samples were recorded in quiet, and another set was mixed with multitalker babble. Twelve younger listeners and 12 older listeners with typical hearing transcribed sentences from the TEP speakers in quiet and noise and rated perceived listening effort using 100-mm visual analog scales. Results revealed that regardless of the age of listener, TEP speakers were significantly less intelligible in noise and that listeners required more listening effort to understand these speakers in noise. Results also revealed that when both hearing status and working memory were controlled, the age of the communication partner did not significantly impact speech intelligibility or perceived listening effort. These results add to the growing literature that people with communication disorders are penalized more than typical speakers when communicating in background noise, even if they show comparable metrics in quiet settings. These results need to be considered when developing strategies for assessing TEP speakers and monitoring treatment success. While the results of this study did not show a statistically significant difference in intelligibility ratings and perceived listening effort based on the age of listener, it is also important to consider factors related to the communication partner/listener when providing therapy and counseling for TEP speakers and their families.
Talking About There-And-Then: Parent Coaching on Decontextualized Language for Mandarin-English Bilingual Children with Developmental Language Disorder (DLD)
(2025-08-01) Guo, Laura Xiaoqian; Pace, Amy
Despite extensive research on language use difficulties in children with Developmental Language Disorder (DLD), substantial gaps exist in intervention evidence. This dissertation describes a parent coaching intervention exploring associations between parental language input and parent-child conversation turns in Mandarin-English bilingual preschoolers with DLD by increasing decontextualized input (narrative and explanation language) in daily routines. The “CHILD” parent coaching program was designed for 20 Mandarin-English bilingual children (typical development/TD=11; DLD=9; mean age = 4;11). Verbal interactions across reading, play, and snack activities were recorded and analyzed before and after coaching. TD children outperformed DLD children on baseline language measures in both languages. Post-coaching, both groups increased decontextualized input and conversation turns, though TD parents consistently used more sophisticated language. The CHILD program effectively supports both populations, demonstrating that bilingual children with DLD benefit from sophisticated language input when appropriately supported, and establishing the feasibility of remote parent coaching.
Electronic Cognitive Aid Use in Parkinson Disease: Usability, Feasibility, and Metacognitive Influences
(2025-01-23) Summers, Dale; Spencer, Kristie
Parkinson disease (PD) is the second most common neurodegenerative disorder. People with PD are prone to a range of cognitive difficulties, and most will eventually progress to dementia. At present, there is emerging evidence for the use of electronic aids in people with PD and mild cognitive impairment, but the benefit of such aids in people with PD and dementia is unknown. The proposed study addressed this gap in two phases by examining the usability and feasibility of an electronic aid, titled IndiAideÂ©, as well as the influence of metacognition on aid use, in persons with PD and a range of cognitive decline. Phase I used a mixed-methods approach to examine ease-of-use and user sentiment and found that people with PD and cognitive decline were able to successfully use the aid when given support and reported generally positive feedback about the app. Phase II assessed global awareness and task-specific awareness. Participants with PD showed patterns consistent with heightened awareness of metacognitive challenges relative to care partners, and they overestimated how much time it would take to complete tasks in IndiAideÂ©. Outcomes include recommendations to ensure IndiAideÂ© is tailored to the needs and preferences of users with PD, as well as clinical recommendations for candidacy for aid use.
Sensory modulation during speech movement planning in stuttering and nonstuttering adults
(2025-01-23) LeBovidge, Elise; Max, Ludo
Stuttering is a complex neurodevelopmental communication disorder with an approximate prevalence of one percent, affecting about eighty million people worldwide. To date, the specific neural mechanisms associated with stuttering and its overt symptoms are still largely unknown, despite evidence of speech and nonspeech sensorimotor differences and extensive sensorimotor network involvement. This dissertation presents novel results from three electrophysiological experiments that aimed to improve our understanding of the sensorimotor mechanisms underlying stuttering. First, I extended our previously established pre-speech auditory modulation (PSAM) paradigm to investigate the modulatory influence of speech movement planning on auditory processing (assessed with auditory evoked potentials) prior to the production of full sentences rather than just isolated words. Second, I investigated whether pre-speech sensory modulation can also be detected in the somatosensory domain. For this study, sensory processing during speech movement planning was assessed by means of somatosensory-evoked potentials in response to experimentally applied orofacial skin stretches. Third, I explored the functional relevance of PSAM in a preliminary study evaluating the correlation between speakers’ extent of PSAM and kinematics-based estimates of their reliance on feedforward versus feedback control. The results from these experiments replicated key findings from our laboratory’s prior work and provide several new insights into the phenomenon of pre-speech sensory modulation in stuttering and nonstuttering speakers. Specifically, Study 1 revealed substantial auditory modulation during speech movement planning for both words and sentences. Study 2 found no pre-speech somatosensory modulation (PSSM) for either typically fluent speakers or speakers who stutter. Thus, the specific cutaneous mechanoreceptors stimulated with the present experimental technique may not be subject to modulation by pre-motor systems involved in speech planning. Study 3 provided preliminary evidence that PSAM is associated with neural mechanisms directly involved in feedforward mechanisms rather than preparing auditory cortex for optimized feedback monitoring. Taken together, the overall findings confirm that adults who stutter show atypical motor-to-auditory interactions during speech movement planning and suggest that this observation relates to a fundamental limitation in the use of feedforward control mechanisms for speech production. The results suggest new testable hypotheses for further research into the neural mechanisms underlying stuttering and speech sensorimotor control in general.
Patterns of Parent-Child Code-Switching and Links to Child Language Development
(2024-10-16) Sohn, Juhee; Pace, Amy
Many bilingual families code-switch (e.g., switch from one language to another) in natural environments, but little is known about its role in language acquisition or the relationship between child and caregiver code-switching. This study identified instances of code-switching (CS) in 23 23- to 36-month-old Spanish-English bilingual toddlers and their caregivers using Language ENvironment Analysis (LENA) audio-recordings during their daily interactions, then investigated the interval frequency of CS occurrence and how it was related to children’s Macarthur-Bates Communicative Developmental Inventory (M-CDI) vocabulary as well as word learning skills. Multiple linear regression models were used to investigate associations between M-CDI vocabulary (English, Spanish, and combined) and children’s age, Language Exposure Assessment Tool (LEAT) scores, child CS, mother CS, and father CS. The same factors were used to investigate associations with word learning skills (English, Spanish, and combined). Interval frequency of CS was highly variable, with a significant correlation between children and fathers’ code-switching. For the English M-CDI, LEAT scores, child CS, and mother CS were significant factors; child CS was the significant factor for the Spanish and combined M-CDIs. Child CS was also the significant factor for English word learning. Results emphasize the importance of children’s CS in language development. In contrast to historical perceptions of CS as a sign of linguistic confusion, findings suggest that CS is an indication of linguistic mastery.
Examining the Links Among Motor Symptoms in Hyperfunctional Voice Disorders, Auditory Discrimination, and Auditory-Motor Function
(2024-09-09) Kapsner-Smith, Mara; Eadie, Tanya
Voice disorders are experienced by nearly a third of people at some point in their lifetimes. Recent evidence suggests impaired auditory-motor function may be a factor in the development or evolution of hyperfunctional voice disorders (HVDs), the most common category. The series of studies outlined in this dissertation form a program of research that focused on further describing the role and nature of such auditory-motor (dys)function in HVDs. In chapter 1, we explored the reliability of common methods used to assess auditory-motor function for speech. Prior to this study, test-retest reliability had never been examined for these methods, which was important for interpretation of study findings across studies outlined in chapters 1 and 3. Results from the study outlined in chapter 1 showed different patterns of reliability of assays of speech auditory-motor control between the domains of voice and articulation, and supported the use of a categorical measure of fundamental frequency (fo) adaptation employed in chapter 3. In chapter 2, we developed a protocol to assess volitional control of small changes in vocal fo and intensity, and tested for group differences between people with and without HVDs. Prior studies of auditory-motor impairment in HVDs found unusually large involuntary changes in vocal fo during auditory-motor adaptive learning tasks. The study outlined in chapter 2 evaluated the possibility that people with HVDs simply are not able to make smaller changes, even when asked to do so volitionally. We found no significant differences in volitional control of fo and intensity between people with and without HVDs. In chapter 3, we evaluated the specificity of vocal auditory-motor impairment in people with HVDs, by replicating studies of fo discrimination and adaptive vocal learning, and extending findings to a second vocal parameter, intensity. In addition, we tested a novel hypothesis that manipulations of auditory feedback, particularly of fo, may elicit a stabilization response in muscles around the larynx, as a form of vocal control. We posited that if this type of response exists, it may be dysregulated in people with HVDs. The results of these studies replicated and extended findings of prior work. Specifically, we found impaired auditory-motor adaptive learning for fo that was similar to prior findings, and a trend for a significant difference from controls in adaptive learning for intensity that was qualitatively different. These findings occurred in the absence of differences in volitional control of small changes in fo and intensity, as reported in chapter 2. Taken together, the results of this series of studies may suggest differences in the causal vs. compensatory nature of these impairments in people with HVDs, which should be explored in future studies. We also found preliminary evidence for laryngeal stabilization as a mechanism of control of vocal fo, which was not present in measures of vocal intensity. Taken together with differences in vocal and articulatory auditory-motor control described in chapter 2, these findings reinforce the importance of refining theoretical models of speech sensorimotor control to account for differences across different parameters of speech. Future directions for research and clinical implications also are discussed.
Factors influencing Audiovisual Speech Integration
(2024-04-26) Gijbels, Liesbeth; Lee, Adrian KC
Audiovisual (AV) integration, identified as a pivotal factor in comprehending speechin noisy environments, is a complex phenomenon. Understanding speech perception, even within a single modality, presents various nuances due to language specificity. When consolidating information from multiple modalities, it is imperative to understand how the listener processes the speech signals in each modality, and how this information is successfully integrated to benefit our speech understanding. Prelinguistic integration mechanisms, such as synchronous temporal information from both modalities, have a significant role in identifying AV events. Yet, linguistic integration mechanisms, like phoneme-viseme connections of the AV speech signal or individual linguistic knowledge, significantly influence speech intelligibility. This dissertation contains two sections. First, we outline three remote AV speech perception tasks across developmental stages, and in developmental disorders such as developmental dyslexia (ages 4-15; n = 261). Second, we present a series of four remote AV psychophysical tasks in adults, ages 21-40 (n = 46), to elucidate the role of prelinguistic and linguistic features pertinent to AV speech integration. For the developmental work we find that weighting assigned to the auditory modality in the AV speech signal serves as a better explanation for individual variability across development than age itself. Moreover, atypical weighting of auditory modality explains differences between children with and without developmental dyslexia on a group level. In adults, our findings suggest that how well temporal asynchrony between the auditory and visual signal is tolerated depends not only on the linguistic complexity of the stimulus, but also on the individual. Prelinguistic information like temporal synchrony perception has an important role in AV speech perception as it endows a 3 dB increase in perceived loudness perception of the target speaker, but this increment interacts with linguistic complexity and temporal asynchrony. Together, these results offer novel insights into different factors influencing AV speech integration.
Relationships Between Auditory Discrimination and Adaptation of Vocal Features of Speech
(2023-09-27) Knutson, Madeline Lis; Eadie, Tanya
The current study evaluated relationships between auditory discrimination and adaptation of vocal features of speech. Previous research suggests relationships between auditory discrimination and adaptation of articulatory features of speech. However, there is conflicting evidence relating auditory discrimination ability and adaptation responses of one specific vocal feature of speech, fundamental frequency (fo). Additionally, there are no published studies evaluating the relationship of auditory discrimination ability and adaptation of intensity. Therefore, the purpose of this study was to investigate relationships between auditory discrimination and adaptation of vocal features of speech, including fundamental frequency (fo) and intensity. Twenty typical speakers underwent auditory discrimination tasks for fo and intensity. They also participated in speech adaptation experiments for fo and intensity. Results indicated no to weak relationship between auditory discrimination and adaptation of fo and no to weak relationship between auditory discrimination and adaptation of intensity. The results therefore support the use and further development of voice-specific models of sensorimotor control for vocal parameters, such as fo and intensity, when analyzing auditory-motor control of vocal features of speech. Implications for future research and clinical studies will be discussed.
Examination of Perceptual Subgroups of Ataxic Dysarthria Through Auditory Free Classification
(2023-09-27) Bouchard, Haley; Spencer, Kristie A
Ataxic dysarthria is highly heterogeneous in its presentation (Duffy, 2020). While the most salient and distinguishing perceptual characteristics center on articulatory and prosodic abnormalities, the manifestation can be quite variable. In fact, some characteristics are even contradictory in nature, such as prosodic excess and prosodic insufficiency. This perceptual heterogeneity has prompted research into possible subgroups within ataxic dysarthria. The current study expands upon the extant literature (e.g., Spencer, Amaral, and Lansford, 2022) which contends that subgroups are mediated by different patterns of motor control, namely an unstable pattern and an inflexible pattern (see Hartelius et al., 2000). In the present study, 25 speakers with ataxic dysarthria from a range of etiologies provided speech samples during two tasks: alternating motion rates (AMR) and connected speech (55 syllables from a reading sample). Seventeen experienced speech-language pathologists served as listeners and completed an auditory free-classification task (Clopper, 2008). Listeners grouped speakers who sounded similar based on their own judgment of the most salient perceptual characteristics. Listener ratings were compared with a priori expert determinations of speakers who fit the instability subgroup profile, the inflexibility subgroup profile, or a mixed subgroup of the two profiles. Results contributed to the existing evidence of perceptually distinct subgroups in ataxic dysarthria, and argue for continued investigation. The findings have implications for models of cerebellar disruption and can inform clinical diagnostic and treatment practices.
Dyadic Coordination of Vocalizations and Pauses in Autistic Children and their Caregivers
(2023-09-27) Choi, Eun Ae; Kover, Sara T
There is emerging evidence that infants with autism spectrum disorder (ASD) demonstrate differences in dyadic coordination of vocalization and pauses with their caregivers throughout infancy and childhood compared to neurotypical children (Northrup et al, 2015; Seidl et al., 2018; Warlaumont et al., 2014). In fact, reduced dyadic coordination of vocalization characterized as larger differences in latency to respond to one another (i.e., latency difference) and overlapping vocalizations were observed to be associated with later receptive and expressive language delays in neurotypical and neurodiverse infant-caregiver dyads (Northrup & Iverson, 2015). However, dyadic coordination and its relationship to language in older, school-age autistic children are poorly understood. The current study investigated dyadic coordination variables (child and caregiver’s percent overlapping speech, latency difference) and conversational state variables (frequency and mean duration of vocalizations and pauses) in dyads of autistic or typically developing school-age children with their caregivers engaged in parent-child-play sessions in the home environment. Results showed that autistic children’s vocalization and within-speaker pauses (i.e., pauses between vocalizations made by the same speaker) were significantly less compared to typically developing children. No group differences were observed in caregivers’ percent overlapping speech or conversational state variables. One dyadic coordination variable, latency difference, significantly and uniquely predicted concurrent receptive vocabulary size, but was not a reliable predictor of composite language scores. Contrary to previous findings, latency difference was positively associated with concurrent language abilities in school-age children. These findings suggest that dyadic coordination variables present differently in older school-age children engaged in parent-child play sessions compared to infant-caregiver dyads or dyads engaged in structured tasks.
Validity and Reliability of Auditory-Perceptual Scales for the Assessment of Stuttering Severity
(2023-09-27) Sokolov, Sima Sheina; Cler, Gabriel
The current study investigated the appropriateness of equal appearing interval scaling, direct magnitude estimation scaling, and visual analog scaling for assessing stuttering severity by determining whether the continuum of stuttering severity, as defined in this study, was prothetic or metathetic. A secondary purpose was to determine interrater reliability of all three scaling methods. The stuttering severity of 20 reading samples was each judged by three groups of 15 listeners each who used the three scaling techniques. The results indicated that the sets of values were related to each other in a linear fashion, indicating that stuttering severity is a metathetic continuum, which is inconsistent with previous studies. These findings suggest that equal appearing interval scaling may be as appropriate as direct magnitude estimation or visual analog scaling for measuring stuttering severity. Future directions should include investigation of the effect of individual training on intrarater reliability and use of expert raters on construct validity and reliability.
Examining the perspectives of augmentative and alternative communication specialists on conducting evaluations with people with Amyotrophic Lateral Sclerosis via telehealth
(2022-09-23) Barton, Mayaka Jane; Baylor, Carolyn
Purpose: To examine the perspectives of speech language pathologists (SLPs), who are augmentative and alternative communication (AAC) specialists working with people with ALS (pALS), on conducting SGD evaluations via tele-AAC vs in-person. Methods: Fifteen AAC specialists were assigned to watch videos of SGD assessments for eight pALS. The SLPs were provided with a checklist based on the AAC Clinical Assessment Project (AAC CAP) protocol that contained 17 different elements of an AAC assessment. The reviewers rated how comparable remote assessment was of each of the 17 elements to in-person evaluation and described any advantages or challenges with the tele-AAC assessment. Results: Across all 17 elements, most reviewers rated tele-AAC assessment as “same/comparable” to in-person sessions. From qualitative comments, the most common advantages that reviewers mentioned of tele-AAC assessment included that it was more functional, increased caregiver availability, and increased pALS’ comfort at home. The most common challenges identified by reviewers were technical difficulties and a limited comprehensive assessment due to the remote modality. In a follow-up survey inquiring about possible changes in attitudes towards tele-AAC following the COVID-19 pandemic, most of the same reviewers indicated that they had transitioned to remote service provision during the pandemic and would likely continue with a mix of in-person and telehealth services depending largely on patient preference and the SLPs own comfort and preference in providing telehealth. Conclusions: AAC specialists have found that conducting SGD assessments via tele-AAC is same or comparable to in-person evaluations with notable advantages and challenges. Tele-AAC should continue to be considered as a service modality for pALS.
Sequence learning on motor and non-motor tasks in people who stutter
(2022-09-23) Kim, Jiwon; Cler, Gabriel
The purpose of this study was to investigate the differences in sequence learning in people who stutter (PWS) and people who are typically fluent (PWTF) using both implicit and explicit sequence learning paradigms while controlling for motor performance. Persistent developmental stuttering (PDS) is a complex neurodevelopmental disorder that impacts 1% of the adult population. It is characterized by the presence of involuntary, audible, or silent prolongations or syllable repetitions most often at the beginning of a word. PWS are thought to have underlying neural differences that impact motor skill learning with further influence on motor sequence learning. In this study, we employed sequence-based learning paradigms to determine the impact of motor output demands on implicit and explicit sequence learning. A total of 28 participants (PWTF = 19; PWS = 9) were recruited for this study. Participants completed a serial reaction time task (SRTT) which measured their ability to learn a 10-item sequence with manual motoroutput in both implicit and explicit contexts in which the presence of a sequence was either concealed or disclosed, respectively. Participants also engaged in a visual statistical learning (VSL) task to measure implicit sequence learning when motor output was not required. Our hypothesis was largely influenced by differences in striatal learning mechanisms in PWS. We hypothesized that PWS would demonstrate less motor learning on implicit tasks when compared to PWTF while no significant differences would be expected on explicit tasks. Second, we hypothesized no significant differences in performance on the non-motor implicit tasks between PWS and PWTF indicating that when motor demands are not a factor, learning is the same. In brief, statistical analysis of our current data set found no significant group differences across all three tasks. Further investigation is necessary to explore the impact of manual motor output on sequence learning using explicit and implicit paradigms.
Procedural Learning in Adults with and without Developmental Language Disorder: The Influence of Manual Motor Demands
(2022-07-14) Bartolo, Samantha Margaret; Cler, Gabriel
The purpose of this research project was to determine differences in procedural learning in adults with and without developmental language disorder (DLD) when manual motor output is and is not required for a learning task. DLD is a neurodevelopmental disorder characterized by unexplained deficits in expressive and/or receptive components of language. The Procedural Deficit Hypothesis (PDH) suggests that individuals with DLD possess deficits in procedural learning and memory due to underlying brain structures responsible for both components of implicit learning and linguistic skill. Relatedly, the Sequential Pattern Learning Deficit Hypothesis (SPLDH) proposes that only sequence-based procedural memory and learning is impaired in DLD populations. In the present study, we employed two sequence-based procedural learning tasks to determine the influence of manual motor output demands on procedural learning. A total of 23 participants (4 = DLD; 19 = typical development) engaged in a serial reaction time task (SRTT) measuring their ability to implicitly learn a visually-presented, 10- element sequence via manual motor output (i.e., keystrokes on a keyboard). These same participants engaged in a visual statistical learning (VSL) task to measure their implicit learning when manual motor output is not demanded. Consistent with the PDH and SPLDH, we hypothesized that adults with DLD would perform worse on motor-dependent sequential learning task when compared to adults with typical development, indicating poorer procedural learning and memory when manual motor output is required. However, we additionally hypothesized that adults with DLD would perform similarly to typically developed adults on the sequential learning task in which manual motor output was not required. Here we present initial results on the preliminary data set. Visual inspection of our initial results indicates that the DLD group performs worse on the SRTT and equivalently on the statistical learning task, consistent with our hypotheses. Statistical analysis did not yield significant results with the current sample size. This study contributes to the existing literature by exploring the influence of motor demands on procedural learning in DLD populations. Implications and future directions are discussed.

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