Self-reported musculoskeletal pain, headache, jaw pain and swallowing dysfunction in a sample of young Saudi adults who stutter.

Objectives: To report the prevalence of musculoskeletal pain, headache, jaw pain and difficulty in swallowing among people who stutter (PWS). METHODS: The cross-sectioal study was conducted from October 3, 2021, to March 21, 2022, after approval from the ethics review committee of King Khalid University, Abha, Saudi Arabia, and comprised adult people who stutter belonging to different regions of Saudi Arabia. They were divided into five groups based on stuttering severity as estimated by Stuttering Severity Instrument-4. Data was collected on musculoskeletal pain in different body areas using a questionnaire.. Data ws analysed using SPSS 22. RESULTS: Of the 101 Arabic-speaking subjects, 63(62.4%) were males and 38(37.6%) were females. The overall mean age was 27±7 years (range: 18-39 years). The largest group was of subjects with moderate severity of stuttering 31(30.6%); 21(68%) males and 10(32%) females. The increase in number of musculoskeletal pain locations was related to the severity of stuttering (p<0.05). The most common musculoskeletal pain sites were the lower back 31(31%), neck 26(26%) and shoulder 26(26%). Frequent headaches and difficulty chewing hard food due to jaw pain were reported by 49(49%) and 22(22%) participants, respectively (p<0.05). Swallowing difficulty was reported by 9(9%) participants (p>0.05). CONCLUSIONS: Widespread chronic musculoskeletal pain of low intensity was found to be common among people who stuttered, and the number of pain locations was positively related to stuttering severity.

A two-case study of coarticulation in stuttered speech. An articulatory approach.

This study aims to describe the coarticulatory behaviour in stuttered speech from an articulatory point of view. Its purpose is to assess the nature of transitions between a stuttered phone and preceding and subsequent phones. Two persons who stutter were recorded by means of an electromagnetic articulograph while reading a text. The vertical movements of upper and lower lips, tongue body, tongue tip and mandible were extracted. They were then analysed during a stuttering moment and linked to the acoustic type of disfluency. Our findings showed several configurations of coarticulatory behaviour in terms of supraglottic articulatory movements. While disfluencies can be the result of a disrupted coarticulatory configuration, no systematicity has been found. Moreover, all acoustic types of disfluencies are represented in several coarticulatory configurations. Therefore, a stuttering-like disfluency is not always due to a coarticulatory disturbance, since correct coarticulatory patterns can be observed both between the disfluent sound and its previous and subsequent sounds. Furthermore, they suggest that the acoustic classification of disfluencies does not seem important for the coarticulatory behaviour.

The effect of manual movements on stuttering in individuals with down syndrome.

PURPOSE: Stuttering may disrupt the speech of individuals with Down syndrome (DS), but standard stuttering therapies may be less adapted to these clients' needs. This study examined if their strength in gesture use can lead to the development of a new stuttering therapy. METHOD: Eighteen individuals with DS who stutter participated in an experimental task. During this task, they produced sentences in three different conditions: once without the ability to use gestures, once while moving the mouth of a hand puppet synchronous with their speech, and once while making beat gestures along their speech. Stuttering frequency was measured and compared between conditions while controlling for the effect of articulation rate. RESULTS: The experimental hand puppet and beat condition did not affect the stuttering frequency, but the covariate articulation rate did. An exploratory posthoc analysis showed that the articulation rate decreased during the experimental hand puppet and beat condition. Manual movements in the present task might only induce fluency through articulation rate reduction. However, analyses at individual level show significant interindividual variability. CONCLUSION: Individual analyses show that effect on stuttering frequency cannot be attributed entirely to articulation rate reduction and that beat gestures might still play a role. However, at this point, there is not enough direct evidence to implement beat gestures in current stuttering therapy.

Expanding the speech and language phenotype in Koolen-de Vries syndrome: late onset and periodic stuttering a novel feature.

Speech and language impairment is core in Koolen-de Vries syndrome (KdVS), yet only one study has examined this empirically. Here we define speech, language, and functional/adaptive behaviour in KdVS; while deeply characterising the medical/neurodevelopmental phenotype in the largest cohort to date. Speech, language, literacy, and social skills were assessed using standardised measures, alongside an in-depth health and medical questionnaire. 81 individuals with KdVS were recruited (35 female, mean age 9y 10mo), 56 of whom harboured the typical 500-650 kb 17q21.31 deletion. The core medical phenotype was intellectual disability (largely moderate), eye anomalies/vision disturbances, structural brain anomalies, dental problems, sleep disturbance, musculoskeletal abnormalities, and cardiac defects. Most were verbal (62/81, 76.5%), while minimally-verbal communicators used alternative and augmentative communication (AAC) successfully in spite of speech production delays. Speech was characterised by apraxia (39/61, 63.9%) and dysarthria (28/61, 45.9%) in verbal participants. Stuttering was described in 36/47 (76.6%) verbal participants and followed a unique trajectory of late onset and fluctuating presence. Receptive and expressive language abilities were commensurate with one another, but literacy skills remained a relative weakness. Social competence, successful behavioural/emotional control, and coping skills were areas of relative strength, while communication difficulties impacted daily living skills as an area of comparative difficulty. Notably, KdVS individuals make communication gains beyond childhood and should continue to access targeted therapies throughout development, including early AAC implementation, motor speech therapy, language/literacy intervention, as well as strategies implemented to successfully navigate activities of daily living that rely on effective communication.

Developmental stuttering, physical concomitants associated with stuttering, and Tourette syndrome: A scoping review.

BACKGROUND AND PURPOSE: Developmental stuttering and Tourette syndrome (TS) are common neurodevelopmental disorders. Although disfluencies may co-occur in TS, their type and frequency do not always represent pure stuttering. Conversely, core symptoms of stuttering may be accompanied by physical concomitants (PCs) that can be confused for tics. This scoping review aimed to explore the similarities and differences between stuttering and tics in terms of epidemiology, comorbidities, phenomenology, evolution, physiopathology, and treatment. We also described the nature of PCs in stuttering and disfluencies in TS. METHODS: A literature search on Medline, Embase and PsycInfo was executed in March 2022. From 426 studies screened, 122 were included in the review (a majority being narrative reviews and case reports). RESULTS: TS and stuttering have several epidemiological, phenomenological, comorbidity, and management similarities suggesting shared risk factors and physiopathology (involving the basal ganglia and their connections with speech and motor control cortical regions). PCs in stuttering commonly involve the face (eyelids, jaw/mouth/lip movements) and sometimes the head, trunk and limbs. PCs can be present from early stages of stuttering and vary over time and within individuals. The function of PCs is unknown. Some individuals with TS have a distinct disfluency pattern, composed of a majority of typical disfluencies (mostly between-word disfluencies), and a mix of cluttering-like behaviors, complex phonic tics (e.g. speech-blocking tics, echolalia, palilalia), and rarely, atypical disfluencies. CONCLUSION: Future investigations are warranted to better understand the complex relationships between tics and stuttering and address the management of disfluencies in TS and PCs in stuttering.

Culture and listeners' gaze responses to stuttering.

BACKGROUND: It is frequently observed that listeners demonstrate gaze aversion to stuttering. This response may have profound social/communicative implications for both fluent and stuttering individuals. However, there is a lack of empirical examination of listeners' eye gaze responses to stuttering, and it is unclear whether cultural background plays a role in regulating listeners' eye gaze response to stuttering. AIM: To examine listeners' eye gaze responses to stuttering speech relative to fluent speech in three cultural groups. METHODS & PROCEDURES: Eighteen African-American, 18 European-American and 18 Chinese adults were audiovisually presented with three stuttering and three fluent speech samples, when an eye-tracking device simultaneously recorded their gaze behaviours. The targets of listeners' eye gaze included four regions of interest (ROIs) on the speaker's face: eyes, nose, mouth and outside (i.e., everything else). Listeners' per cent of gaze time, gaze fixation count and average duration of gaze fixation were analysed with repeated-measures ANOVAs regarding each ROI as functions of the speaker's fluency status and listeners' cultural background. OUTCOMES & RESULTS: When observing stuttering speech, listeners tended to reduce gaze fixation duration on the speaker's eyes and increase their gaze time on the mouth. However, different from the two American groups, the Chinese group reduced their gaze time on the speaker's mouth. In addition, the Chinese participants' gaze behaviours were more focused on the ROI of outside, whereas the two American groups showed a similar focus on the ROIs of eyes and mouth. CONCLUSIONS & IMPLICATIONS: All groups of listeners responded to stuttering with gaze aversions mainly contributed to by a reduction in gaze fixation duration rather than gaze fixation number. This pattern of gaze aversion suggests that stuttering oppresses listeners with an emotional and/or cognitive overload. Attention shift and compensation strategies for speech signal degradation may also account for listeners' gaze responses to stuttering. Cultural differences in eye gaze responses to stuttering were observed mainly between Chinese and American listeners.

Oral sensorimotor integration in adults who stutter.

OBJECTIVE: To investigate the relationship between tendon vibration sensitivity and oral motor control in adults who stutter (AWS). PATIENTS AND METHODS: Ten controls and 10 AWS first made jaw-opening movements from a closed-mouth position to an 18-mm target. Then, masseter tendon vibration was applied during jaw opening in a separate condition to test whether accuracy and/or variability is related to movement undershoot. RESULTS: AWS made less accurate and more variable jaw movements than controls without visual feedback. Among the normally fluent adult participants, higher accuracy and lower variability were significantly related to masseter vibration undershoot, but significant correlations were not observed for AWS. CONCLUSION: These results suggest that increased tendon vibration sensitivity may be related to more refined oral motor control. Subtle sensorimotor limitations could be present in stuttering that render speech more susceptible to breakdowns.

Influence of gestures on the intelligibility and comprehensibility of utterances with stuttering events in individuals with Down syndrome.

INTRODUCTION: Individuals with Down syndrome (DS) often stutter, which can affect their speech intelligibility. Previous research has shown that manual signs can enhance speech intelligibility and comprehensibility. It remains unclear to what extent spontaneous hand gestures, such as iconic and beat gestures, may enhance intelligibility and/or comprehensibility during utterances with stuttering events. METHODS: Eleven individuals with DS who stutter provided video-recorded speech samples. From these samples, 60 utterances containing a stuttering event were selected. In half of them, the stuttering events were accompanied by gestures; in the other half, the stuttering events were not accompanied by gestures. The samples were shown to 250 assessors who were blind to the study's goals. Each sample was shown in three visibility conditions: 1) video-with-audio, 2) video-with-audio but with the speaker's mouth covered and 3) audio-only. The assessors rated speech intelligibility on a 7-point Likert scale and transcribed the speech sample. The effect of gesture production, gesture type and the visibility conditions on comprehensibility and intelligibility was examined with a hierarchical multiple linear regression. RESULTS: When a speaker had used a gesture during a stuttering event, the Likert scale score increased with 0.47 and the accuracy of transcription with 9.07%. There was no difference in effect between the different gesture types. Despite the effect from gesture use, there was no effect of the visibility conditions on the Likert scale or transcription score. CONCLUSIONS: Gestures positively affect intelligibility and comprehensibility of utterances with stuttering events in individuals with DS by altering the speech production. The possibility of beat gestures as a therapy method should be examined, with caution for the development of maladaptive behaviours.

Stuttering inhibition via visual feedback at normal and fast speech rates.

BACKGROUND: Immediate and drastic reductions in stuttering are found when speech is produced in conjunction with a variety of second signals (for example, auditory choral speech and its permutations, and delayed auditory feedback). Initially, researchers suggested a decreased speech rate as a plausible explanation for the reduction in stuttering as people who stutter produced speech under second signals. However, this explanation was refuted by research findings that demonstrated reductions in stuttering at both normal and fast speech rates under second signals. Recent studies have also demonstrated significant reductions in stuttering from second signals delivered via the visual modality. However, the question as to whether stuttering can be substantially reduced at normal and fast speech rates under visual speech feedback conditions has yet to be answered. AIMS: The current study investigated stuttering frequency reduction at normal and fast speech rates across different visual speech feedback conditions relative to a no-visual feedback condition. METHODS & PROCEDURES: Ten adults who stutter recited memorized tokens of eight to 13 syllables under five visual speech feedback conditions at both normal and fast speech rates. Visual speech feedback conditions consisted of participants viewing the lower portion of their face (that is, lips, jaw, and base of the nose) on a monitor as they produced the aforementioned utterances. Conditions consisted of (1) no-visual feedback condition, (2) 0 ms (simultaneous visual speech feedback), (2) a 50-ms delay, (3) a 200-ms delay, and (4) a 400-ms delay. OUTCOMES & RESULTS: A significant main effect of visual speech feedback on stuttering frequency was found (p= 0.001) with no significant main effect of speech rate or the interaction between speech rate and visual speech feedback. Relative to the no-visual feedback condition, the feedback conditions produced reductions in stuttering ranging from 27% (0 ms) to 62% (400 ms). Post-hoc comparisons revealed that all of the delay conditions differed significantly from the simultaneous feedback (p= 0.017) and the no-visual feedback conditions (p= 0.0002) while no significant differences between delay conditions (that is, 50, 200, and 400 ms) were observed. CONCLUSIONS & IMPLICATIONS: The current findings demonstrate the capabilities of visual speech feedback signals to reduce stuttering frequency that is independent of the speaker's rate of speech. Possible strategies are suggested to transfer these findings into naturalistic and clinical settings, though further research is warranted.

White matter microstructural differences underlying beta oscillations during speech in adults who stutter.

The basal ganglia-thalamocortical (BGTC) loop may underlie speech deficits in developmental stuttering. In this study, we investigated the relationship between abnormal cortical neural oscillations and structural integrity alterations in adults who stutter (AWS) using a novel magnetoencephalography (MEG) guided tractography approach. Beta oscillations were analyzed using sensorimotor speech MEG, and white matter pathways were examined using tract-based spatial statistics (TBSS) and probabilistic tractography in 11 AWS and 11 fluent speakers. TBSS analysis revealed overlap between cortical regions of increased beta suppression localized to the mouth motor area and a reduced fractional anisotropy (FA) in the AWS group. MEG-guided tractography showed reduced FA within the BGTC loop from left putamen to subject-specific MEG peak. This is the first study to provide evidence that structural abnormalities may be associated with functional deficits in stuttering and reflect a network deficit within the BGTC loop that includes areas of the left ventral premotor cortex and putamen.

Gaze aversion to stuttered speech: a pilot study investigating differential visual attention to stuttered and fluent speech.

BACKGROUND: People who stutter are often acutely aware that their speech disruptions, halted communication, and aberrant struggle behaviours evoke reactions in communication partners. Considering that eye gaze behaviours have emotional, cognitive, and pragmatic overtones for communicative interactions and that previous studies have indicated increased physiological arousal in listeners in response to stuttering, it was hypothesized that stuttered speech incurs increased gaze aversion relative to fluent speech. The possible importance in uncovering these visible reactions to stuttering is that they may contribute to the social penalty associated with stuttering. AIMS: To compare the eye gaze responses of college students while observing and listening to fluent and severely stuttered speech samples produced by the same adult male who stutters. METHODS & PROCEDURES: Twelve normally fluent adult college students watched and listened to three 20-second audio-video clips of the face of an adult male stuttering and three 20-second clips of the same male producing fluent speech. Their pupillary movements were recorded with an eye-tracking device and mapped to specific regions of interest (that is, the eyes, the nose and the mouth of the speaker). OUTCOMES & RESULTS: Participants spent 39% more time fixating on the speaker's eyes while witnessing fluent speech compared with stuttered speech. In contrast, participants averted their direct eye gaze more often and spent 45% more time fixating on the speaker's nose when witnessing stuttered speech compared with fluent speech. These relative time differences occurred as a function of the number of fixations in each area of interest. Thus, participants averted their gaze from the eyes of the speaker more frequently during the stuttered stimuli than the fluent stimuli. CONCLUSIONS & IMPLICATIONS: This laboratory study provides pilot data suggesting that gaze aversion is a salient response to the breakdown in communication that occurs during stuttering. This response may occur as a result of emotional, cognitive, and pragmatic factors in communication partners. Regardless of the factors contributing to the response, its primary importance may be that gaze aversion is a visible communication partner signal informing the person stuttering that something is amiss in the interaction and hence, may contribute to inducing negative emotions in the persons stuttering, via engagement of the mirror neuron system. We suggest that witnessing and interpreting communication partner responses to stuttering may play a role when a person who stutters engages in future interactions, perhaps contributing to the development of covert strategies to hide stuttering.

Surface Electrical Stimulation for Persistent Stuttering and Concomitant Orofacial Disorders: A Multiple Case Study.

This multiple case study analysis describes the immediate effects on speech fluency of transcutaneous electrical nerve stimulation (TENS) applied to participants with persistent stuttering and concomitant orofacial disorders. Study participants were 14 adolescents and adults who stuttered and had jaw clenching bruxism or mouth breathing. Participants experienced low-frequency TENS applied at mild motor level for 20 minutes with electrodes placed at the lower third of the face (Area A), submandibular region (Area B), posterior neck (Area C), or shoulder girdle (Area D), with speech fluency assessed immediately before and after each stimulation.For participants with stuttering and bruxism, AB stimulation reduced the median frequency of syllables stuttered by 27% and reduced the median duration of the three highest stuttering moments by 29%. In addition, for participants with stuttering and mouth breathing, CD stimulation reduced the median duration of the three highest stuttering moments by 28% and increased their median speech rate by 113%. As a single session of TENS may help participants with stuttering and concomitant orofacial disorders better use fluency shaping techniques, the therapeutic potential of TENS for treating stuttering should be further investigated.

Neuronavigated rTMS inhibition of right pars triangularis anterior in stuttering: Differential effects on reading and speaking.

Functional neuroimaging studies show an overactivation of speech and language related homologous areas of the right hemisphere in persons who stutter. In this study, we inhibited Broca's homologues using 1 Hz repetitive transcranial magnetic stimulation (rTMS) and assessed its effects on stuttering severity. The investigated cortical areas included pars opercularis (BA44), anterior and posterior pars triangularis (BA45), mouth area on the primary motor cortex (BA4). We collected reading and speaking samples before and after rTMS sessions and calculated the percentage of syllables stuttered. Only right anterior pars triangularis stimulation induced significant changes in speech fluency. Notably, the effects were differential for reading and speaking conditions. Overall, our results provide supportive evidence that right anterior BA45 may be a critical region for stuttering. The observed differential effects following the inhibition of right anterior BA45 merits further study of contributions of this region on different language domains in persons who stutter.

Bite-block perturbation in people who stutter: immediate compensatory and delayed adaptive processes.

UNLABELLED: This exploratory study investigated sensory-motor mechanisms in five people who stutter (PWS) and five people who do not (PNS). Lip kinematic and coordination data were recorded as they produced bi-syllabic nonwords at two rates (normal and fast) in three conditions (jaw-free, immediately after insertion of a bite-block, and after a 10-min accommodation period). At normal speech rates, effects of bite-blocks on lip kinematics were similar for both PWS and PNS speakers showing larger amplitudes, peak velocities, shorter durations and more stable movement cycle patterns. However, at fast speech rates upper lip responses of PWS exhibited larger amplitudes and peak velocities. At both speech rates, the presence of a bite-block changed movement coordination patterns only for PNS. However, at fast speech rates bite-blocks decreased variability of coordination patterns for both groups. No adaptive changes in movement stability were found for either group, but a practice-related increase in lower lip peak velocity was found at normal speech rates. These findings indicate that bite-block perturbation did not exacerbate any hypothesized limitation or difficulty in controlling individual articulatory movements or their coordination in PWS. The results also support the position that specific motor control strategies are used by PWS as compared to PNS to compensate for bite-block perturbations under increased speech rate demands. LEARNING OUTCOMES: The reader will be able to: (1) distinguish between compensatory and adaptive responses to bite-block perturbation; (2) explain the measurement of articulatory stability; (3) summarize the potential role of motor control strategies in people who stutter; and (4) discuss the assumptions of the motor skills approach to stuttering.

Speech motor correlates of treatment-related changes in stuttering severity and speech naturalness.

Participants of stuttering treatment programs provide an opportunity to evaluate persons who stutter as they demonstrate varying levels of fluency. Identifying physiologic correlates of altered fluency levels may lead to insights about mechanisms of speech disfluency. This study examined respiratory, orofacial kinematic and acoustic measures in 35 persons who stutter prior to and as they were completing a 1-month intensive stuttering treatment program. Participants showed a marked reduction in stuttering severity as they completed the treatment program. Coincident with reduced stuttering severity, participants increased the amplitude and duration of speech breaths, reduced the rate of lung volume change during inspiration, reduced the amplitude and speed of lip movements early in the test utterance, increased lip and jaw movement durations, and reduced syllable rate. A multiple regression model that included two respiratory measures and one orofacial kinematic measure accounted for 62% of the variance in changes in stuttering severity. Finally, there was a weak but significant tendency for speech of participants with the largest reductions in stuttering severity to be rated as more unnatural as they completed the treatment program.

Jaw-phonatory coordination in chronic developmental stuttering.

UNLABELLED: A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies, which show that movement coordination depends on intact proprioception. We hypothesized that adult stutterers would show deficient jaw-phonatory coordination relative to control participants. The task required initiation of phonation as a jaw-opening movement passed through a narrow spatial target. Target amplitude and jaw movement speed were varied. The stuttering group showed significantly higher movement error and spatial variability in jaw-phonatory coordination compared to the control group, but group differences in movement velocity or duration were not found. The aberrant jaw-phonatory coordination of the stuttering participants suggests that stuttering is associated with an oral proprioceptive limitation, although, the findings are also consistent with a motor control deficit. LEARNING OUTCOMES: As a result of this activity, reader will (1) learn about a hypothesis and evidence supporting the view that a sensorimotor deficit contributes to chronic developmental stuttering and (2) will obtain information about the role of proprioception in multi-articulatory coordination and how it can be tested using an oral-phonatory coordination task.

Anomalous sensorimotor integration in adults who stutter: a tendon vibration study.

Anomalies in oral movement control have been identified in stuttering, which suggest this speech disorder involves a sensorimotor deficit. To test whether adults who stutter (AWS) display aberrant proprioceptive function, masseter tendon vibration was used to manipulate jaw proprioception as AWS and normal speakers performed a jaw-opening task. A movement amplitude reduction in the vibration condition was observed in both groups indicating the movements of AWS and controls were influenced in a similar manner by altering masseter proprioception. However, the undershoot magnitude was reduced in AWS relative to the control participants indicating a subtle difference in proprioceptive integration among the stuttering participants. Our interpretation is that AWS use proprioceptive information less efficiently than normal speakers, which could interfere with sensorimotor integration during speech production.

Oral kinesthetic deficit in adults who stutter: a target-accuracy study.

The current study was based on the hypothesis that chronic developmental stuttering in adults involves a deficiency in oral kinesthesia. The authors used a target-accuracy task to compare oral kinesthesia in adults who stutter (n = 17) and in normal speakers (n = 17). During the task, participants were instructed to make accurate jaw-opening movements in visual and nonvisual feedback conditions. The authors further contrasted oral movement control in a normal response time condition with that in a reaction time condition. Overall, the adults who stutter consistently made significantly less accurate and more variable movements than the control participants in the nonvisual condition, but particularly in the reaction time condition. In general, the present findings suggest that chronic developmental stuttering involves an oral kinesthetic deficiency, although without direct measures of somatosensory function, one cannot exclude a motor deficit interpretation.

Motor practice effects and sensorimotor integration in adults who stutter: Evidence from visuomotor tracking performance.

PURPOSE: The purpose of this study was to utilize a visuomotor tracking task, with both the jaw and hand, to add to the literature regarding non-speech motor practice and sensorimotor integration (outside of auditory-motor integration domain) in adults who do (PWS) and do not (PWNS) stutter. METHOD: Participants were 15 PWS (14 males, mean age = 27.0) and 15 PWNS (14 males, mean age = 27.2). Participants tracked both predictable and unpredictable moving targets separately with their jaw and their dominant hand, and accuracy was assessed by calculating phase and amplitude difference between the participant and the target. Motor practice effect was examined by comparing group performance over consecutive tracking trials of predictable conditions as well as within the first trial of same conditions. RESULTS: Results showed that compared to PWNS, PWS were not significantly different in matching either the phase (timing) or the amplitude of the target in both jaw and hand tracking of predictable and unpredictable targets. Further, there were no significant between-group differences in motor practice effects for either jaw or hand tracking. Both groups showed improved tracking accuracy within and between the trials. CONCLUSION: Our findings revealed no statistically significant differences in non-speech motor practice effects and integration of sensorimotor feedback between PWS and PWNS, at least in the context of the visuomotor tracking tasks employed in the study. In general, both talker groups exhibited practice effects (i.e., increased accuracy over time) within and between tracking trials during both jaw and hand tracking. Implications for these results are discussed. EDUCATIONAL OBJECTIVES: The reader will be able to: (a) describe the importance of motor learning and sensory-motor integration for speech, (b) summarize past research on PWS's performance during speech and nonspeech motor tasks, and (c) describe the relation between different aspects of speech and non-speech motor control and stuttering.

Functional organization of the auditory cortex is different in stutterers and fluent speakers.

Impaired auditory feedback has been suggested to cause stuttering, and subtle irregularities of audition have been reported in behavioural studies. To characterize processing at the auditory cortical level, we recorded neuromagnetic responses to monaural tones in nine stutterers and 10 fluent speakers while the subjects were reading silently, with mouth movements only, aloud, and in chorus with another person. The basic functional organization of the auditory cortices was found to be different in stutterers and controls. The altered interhemispheric balance in stutterers was affected by speech production, due to changes in the left auditory cortical representation, and more severely by self-paced than accompanied speech. This may lead to transient non-optimal interpretation of the auditory input and affect speech fluency.