Speech auditory‐motor adaptation to formant‐shifted feedback lacks an explicit component: reduced adaptation in adults who stutter reflects limitations in implicit sensorimotor learning

2021 ◽  
Author(s):  
Kwang S. Kim ◽  
Ludo Max
Keyword(s):  
Motor Adaptation ◽  
Sensorimotor Learning ◽  
Adults Who Stutter

scholarly journals Speech auditory-motor adaptation lacks an explicit component: reduced adaptation in adults who stutter reflects limitations in implicit sensorimotor learning

2020 ◽  
Author(s):  
Kwang S. Kim ◽  
Ludo Max
Keyword(s):  
Motor Learning ◽  
Implicit Learning ◽  
Auditory Feedback ◽  
Large Body ◽  
Motor Adaptation ◽  
Auditory Target ◽  
Sensorimotor Learning ◽  
Adults Who Stutter ◽  
Feedback Modalities ◽  
Sensory Prediction

AbstractThe neural mechanisms underlying stuttering remain poorly understood. A large body of work has focused on sensorimotor integration difficulties in individuals who stutter, including recently the capacity for sensorimotor learning. Typically, sensorimotor learning is assessed with adaptation paradigms in which one or more sensory feedback modalities are experimentally perturbed in real-time. Our own previous work on speech with perturbed auditory feedback revealed substantial auditory-motor learning limitations in both children and adults who stutter (AWS). It remains unknown, however, which sub-processes of sensorimotor learning are impaired. Indeed, new insights from research on upper-limb motor control indicate that sensorimotor learning involves at least two distinct components: (a) an explicit component that includes intentional strategy use and presumably is driven by target error, and (b) an implicit component that updates an internal model without awareness of the learner and presumably is driven by sensory prediction error. Here, we attempted to dissociate these components for speech auditory-motor learning in AWS vs. adults who do not stutter (AWNS). Our formant-shift auditory-motor adaptation results replicated previous findings that such sensorimotor learning is limited in AWS. Novel findings are that neither control nor stuttering participants reported any awareness of changing their productions in response to the auditory perturbation, and that neither group showed systematic drift in auditory target judgments made throughout the adaptation task. These results indicate that speech auditory-motor adaptation relies exclusively on implicit learning processes. Thus, limited adaptation in AWS reflects poor implicit sensorimotor learning. Keywords: stuttering, adaptation, auditory feedback, sensorimotor learning, implicit learning Speech auditory-motor adaptation lacks an explicit component: reduced adaptation in adults who stutter reflects limitations in implicit sensorimotor learning

scholarly journals Auditory-motor adaptation is reduced in adults who stutter but not in children who stutter

2017 ◽  
Vol 21 (2) ◽  
pp. e12521 ◽  
Author(s):  
Ayoub Daliri ◽  
Elizabeth A. Wieland ◽  
Shanqing Cai ◽  
Frank H. Guenther ◽  
Soo-Eun Chang
Keyword(s):  
Motor Adaptation ◽  
Adults Who Stutter

scholarly journals Cortico-Cerebellar Networks Drive Sensorimotor Learning in Speech

2017 ◽  
Author(s):  
Daniel R. Lametti ◽  
Harriet J. Smith ◽  
Phoebe Freidin ◽  
Kate E. Watkins
Keyword(s):  
Motor Cortex ◽  
Error Correction ◽  
Real Time ◽  
Speech Production ◽  
Motor Adaptation ◽  
Sensorimotor Learning ◽  
Vowel Sound ◽  
Cerebellar Tdcs ◽  
Second Formant

AbstractThe motor cortex and cerebellum are thought to be critical for learning and maintaining motor behaviours. Here we use tDCS to test the role of the motor cortex and cerebellum in sensorimotor learning in speech. During productions of ‘head’, ‘bed’, and ‘dead’, the first formant of the vowel sound was altered in real-time towards the first formant of the vowel sound in ‘had’, ‘bad’, and ‘dad’. Compensatory changes in first and second formant production were used as a measure of motor adaptation. TDCS to either the motor cortex or the cerebellum improved sensorimotor learning in speech compared to sham stimulation. However, in the case of cerebellar tDCS, production changes were restricted to the source of the acoustical error (i.e. the first formant). Motor cortex tDCS drove production changes that offset errors in the first formant, but, unlike cerebellar tDCS, adaptive changes in the second formant also occurred. The results suggest that motor cortex and cerebellar tDCS have both shared and dissociable effects on motor adaptation. The study provides initial causal evidence in speech production that the motor cortex and the cerebellum support different aspects of sensorimotor learning. We propose that motor cortex tDCS drives sensorimotor learning towards previously learned patterns of movement, while cerebellar tDCS focuses sensorimotor learning on error correction.

scholarly journals Dissociated development of speech and limb sensorimotor learning in stuttering: speech auditory-motor learning is impaired in both children and adults who stutter

2020 ◽  
Author(s):  
Kwang S. Kim ◽  
Ayoub Daliri ◽  
John Randall Flanagan ◽  
Ludo Max
Keyword(s):  
Motor Learning ◽  
Neurodevelopmental Disorder ◽  
Visuomotor Adaptation ◽  
Sensorimotor Learning ◽  
Typically Developing ◽  
Older Children ◽  
Visuomotor Learning ◽  
Report Data ◽  
Adults Who Stutter ◽  
Reach Movements

Stuttering is a neurodevelopmental disorder of speech fluency. Various experimental paradigms have demonstrated that affected individuals show limitations in sensorimotor control and learning. However, controversy exists regarding two core aspects of this perspective. First, it has been claimed that sensorimotor learning limitations are detectable only in adults who stutter (after years of coping with the disorder) but not during childhood close to the onset of stuttering. Second, it remains unclear whether stuttering individuals' sensorimotor learning limitations affect only speech movements or also unrelated effector systems involved in nonspeech movements. We report data from separate experiments investigating speech auditory-motor learning (N = 60) and limb visuomotor learning (N = 84) in both children and adults who stutter versus matched nonstuttering individuals. Both children and adults who stutter showed statistically significant limitations in speech auditory-motor adaptation with formant-shifted feedback. This limitation was more profound in children than in adults and in younger children versus older children. Between-group differences in the adaptation of reach movements performed with rotated visual feedback were subtle but statistically significant for adults. In children, even the nonstuttering groups showed limited visuomotor adaptation just like their stuttering peers. We conclude that sensorimotor learning is impaired in individuals who stutter, and that the ability for speech auditory-motor learning -- which was already adult-like in 3-6 year-old typically developing children -- is severely compromised in young children near the onset of stuttering. Thus, motor learning limitations may play an important role in the fundamental mechanisms contributing to the onset of this speech disorder.

scholarly journals Limited Pre-Speech Auditory Modulation in Individuals Who Stutter: Data and Hypotheses

2019 ◽  
Vol 62 (8S) ◽  
pp. 3071-3084 ◽  
Author(s):  
Ludo Max ◽  
Ayoub Daliri
Keyword(s):  
Auditory Feedback ◽  
Auditory Processing ◽  
Auditory Evoked Potentials ◽  
Motor Adaptation ◽  
Motor Command ◽  
Auditory Evoked Potential ◽  
Movement Planning ◽  
Feedback Signal ◽  
Auditory Modulation ◽  
Adults Who Stutter

Purpose We review and interpret our recent series of studies investigating motor-to-auditory influences during speech movement planning in fluent speakers and speakers who stutter. In those studies, we recorded auditory evoked potentials in response to probe tones presented immediately prior to speaking or at the equivalent time in no-speaking control conditions. As a measure of pre-speech auditory modulation (PSAM), we calculated changes in auditory evoked potential amplitude in the speaking conditions relative to the no-speaking conditions. Whereas adults who do not stutter consistently showed PSAM, this phenomenon was greatly reduced or absent in adults who stutter. The same between-group difference was observed in conditions where participants expected to hear their prerecorded speech played back without actively producing it, suggesting that the speakers who stutter use inefficient forward modeling processes rather than inefficient motor command generation processes. Compared with fluent participants, adults who stutter showed both less PSAM and less auditory–motor adaptation when producing speech while exposed to formant-shifted auditory feedback. Across individual participants, however, PSAM and auditory–motor adaptation did not correlate in the typically fluent group, and they were negatively correlated in the stuttering group. Interestingly, speaking with a consistent 100-ms delay added to the auditory feedback signal–normalized PSAM in speakers who stutter, and there no longer was a between-group difference in this condition. Conclusions Combining our own data with human and animal neurophysiological evidence from other laboratories, we interpret the overall findings as suggesting that (a) speech movement planning modulates auditory processing in a manner that may optimize its tuning characteristics for monitoring feedback during speech production and, (b) in conditions with typical auditory feedback, adults who stutter do not appropriately modulate the auditory system prior to speech onset. Lack of modulation of speakers who stutter may lead to maladaptive feedback-driven movement corrections that manifest themselves as repetitive movements or postural fixations.

scholarly journals Cortico-cerebellar Networks Drive Sensorimotor Learning in Speech

2018 ◽  
Vol 30 (4) ◽  
pp. 540-551 ◽  
Author(s):  
Daniel R. Lametti ◽  
Harriet J. Smith ◽  
Phoebe F. Freidin ◽  
Kate E. Watkins
Keyword(s):  
Motor Cortex ◽  
Error Correction ◽  
Direct Current ◽  
Motor Adaptation ◽  
Sensorimotor Learning ◽  
Vowel Sound ◽  
Motor Behaviors ◽  
Cerebellar Tdcs ◽  
Second Formant

The motor cortex and cerebellum are thought to be critical for learning and maintaining motor behaviors. Here we use transcranial direct current stimulation (tDCS) to test the role of the motor cortex and cerebellum in sensorimotor learning in speech. During productions of “head,” “bed,” and “dead,” the first formant of the vowel sound was altered in real time toward the first formant of the vowel sound in “had,” “bad,” and “dad.” Compensatory changes in first and second formant production were used as a measure of motor adaptation. tDCS to either the motor cortex or the cerebellum improved sensorimotor learning in speech compared with sham stimulation ( n = 20 in each group). However, in the case of cerebellar tDCS, production changes were restricted to the source of the acoustical error (i.e., the first formant). Motor cortex tDCS drove production changes that offset errors in the first formant, but unlike cerebellar tDCS, adaptive changes in the second formant also occurred. The results suggest that motor cortex and cerebellar tDCS have both shared and dissociable effects on motor adaptation. The study provides initial causal evidence in speech production that the motor cortex and the cerebellum support different aspects of sensorimotor learning. We propose that motor cortex tDCS drives sensorimotor learning toward previously learned patterns of movement, whereas cerebellar tDCS focuses sensorimotor learning on error correction.

Self-Compassion and Quality of Life in Adults Who Stutter

2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd
Keyword(s):  
Quality Of Life ◽  
Social Connectedness ◽  
The Self ◽  
Future Research ◽  
Self Compassion ◽  
Adults Who Stutter ◽  
And Gender ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.

Group Experiences and Individual Differences in Stuttering

2019 ◽  
Vol 62 (12) ◽  
pp. 4335-4350 ◽  
Author(s):  
Seth E. Tichenor ◽  
J. Scott Yaruss
Keyword(s):  
Individual Differences ◽  
Support Groups ◽  
Support Group ◽  
Affective States ◽  
Life Outcomes ◽  
Self Help ◽  
Wide Range ◽  
Group Experiences ◽  
History Of ◽  
Adults Who Stutter

Purpose This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings. Method In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences. Results Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states. Conclusion Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.

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