Auditory Attentional Set-Shifting and Inhibition in Children Who Stutter

Mental state verb use in play by preschool-age children who stutter and their mothers

INTRODUCTION

Preschool-age children use mental state verbs (MSVs; e.g., think, know) to reference thoughts and other cognitive states. In play-based language, MSV use requires conversational flexibility, as speakers shift from discussion of actions happening in the here-and-now to more abstract discussion of mental states. Some evidence suggests that children who stutter (CWS) demonstrate subtle differences in shifting on experimental tasks of cognitive flexibility, differences which may extend to conversational flexibility. This study explored MSV use in conversational language between CWS and their mothers.

METHODS

Thirty-five preschool-age CWS and 35 age- and gender-matched children who do not stutter (CWNS), all performing within the typical range on standardized language testing, conversed with their mothers during play. Samples were transcribed and coded for MSV use.

RESULTS

No between-group differences were observed in MSV use, either between the CWS and CWNS or between the groups of mothers. Age and language skills were positively associated with MSV use in the CWNS group only. For both groups of dyads, mothers' MSV use corresponded at least to some extent to their children's language skills. Finally, correspondence between CWNS and their mothers was observed for two conversational language measures, representing lexical diversity and morphosyntax; this overall pattern was not observed in the CWS dyad group.

CONCLUSIONS

Although these findings point to similar use of MSVs among the groups of children and their mothers, for the CWS group, the patterns of use in relation to age and language skills are somewhat different from developmental expectations.

Inhibitory Control, Cognitive Flexibility, and the Production of Disfluencies in Children Who Do and Do Not Stutter

PURPOSE

Differences in inhibitory control and cognitive flexibility between children who stutter (CWS) and children who do not stutter (CWNS) have been previously demonstrated. The aim of the current study was to investigate whether the previously reported inhibitory control- and cognitive flexibility-related performance costs for CWS are associated with the number of speech disfluencies that they produce.

METHOD

Participants were 19 CWS (Mage = 7.58 years, range: 6.08-9.17) and 19 CWNS matched on age and gender (Mage = 7.58 years, range: 6.08-9.33). Gamma regression models were used to investigate possible associations between performance costs in speed and accuracy measured during a computer task evaluating inhibitory control and cognitive flexibility and the number of speech disfluencies during video-recorded speech samples (story retelling and casual conversation).

RESULTS

Two significant interactions were observed. For both inhibitory control and cognitive flexibility, we identified a significant group and inhibitory control/cognitive flexibility performance-cost interaction in stuttering-like disfluencies (SLDs), indicating that the performance-cost effects on SLD production were significantly higher in the CWS group, compared to the CWNS group.

CONCLUSIONS

CWS with reduced inhibitory control or cognitive flexibility produce more SLDs, but not other disfluencies. These results are partly in line with some previous findings in nonstuttering and stuttering populations linking inhibitory control and cognitive flexibility weaknesses to the production of speech disfluencies.

Delay frustration in children who do and do not stutter: A preliminary study

PURPOSE

Frustration is an emotion often clinically reported by persons who stutter. So far, mainly questionnaire-based studies have reported findings related to increased frustration or decreased frustration tolerance. The aim of this preliminary study was to determine possible group differences between children who stutter (CWS) and children who do not stutter (CWNS) using a behavioral experimental task, as well as to evaluate possible associations with the frequency, duration, and physical concomitants of stuttering disfluencies.

METHOD

Participants were 13 CWS (mean age = 6;05 years) and 13 CWNS (mean age = 6;06 years), matched on age (±4 months) and gender. Frustration tolerance was assessed by the Delay Frustration task. This task includes normal delay, short delay, and long delay trials. Responses during long delay trials provide an indication of frustration tolerance and were recorded across time intervals during the response window.

RESULTS

CWS, compared to CWNS, responded more frequently during the long delay trials, which is indicative of higher delay frustration. The variation in responding across time within intervals was similar for both groups. Decreased frustration tolerance was associated with increased duration of stuttered disfluencies and of physical concomitants.

CONCLUSIONS

In general, the current findings seem to provide support for earlier theoretical conceptualizations about the role of emotional reactivity in the development of stuttering.

Complex working memory in adults with and without stuttering disorders: Performance patterns and predictive relationships

PURPOSE

Available studies of working memory (WM) in speakers who stutter tend to rely on parent report, focus on phonological WM, or measure WM in combination with other processes. The present research aimed to: (1) compare complex WM in adults who stutter (AWS) and adults who do not stutter (AWNS); (2) characterize group performance patterns; and (2) determine whether WM predicts stuttering severity.

METHODS

Eighteen AWS and 20 AWNS completed parallel verbal and spatial span tasks in which to-be-remembered items were interleaved with a distracting task across varying set sizes. Dependent variables included the number of correctly recalled items, accuracy on distraction tasks, and detailed analyses of item-level responses. We further examined whether span scores predicted subjective and objective measures of stuttering severity.

RESULTS

Relative to AWNS, AWS showed poorer recall, specifically on short set sizes in the spatial task. Groups performed similarly on distraction tasks and showed comparable error patterns. Predictive relationships differed by span task and severity measure. Lower verbal span scores predicted greater stuttering impact and more overt stuttering behaviors; lower spatial span scores predicted lower impact and was unrelated to overt behaviors.

CONCLUSIONS

Findings suggest that AWS differ subtly from AWNS in WM performance. Group differences became more apparent under certain task conditions but could not be attributed to specific underlying processes. Data further indicated a complex relationship between WM and stuttering severity. Overall, results corroborate previous studies linking stuttering to domain-general weaknesses, but highlight the need for additional research to clarify the nature of this relationship.

Complex response inhibition and cognitive flexibility in school-aged Cypriot-Greek-speaking children who stutter

PURPOSE

Over the last few years, research findings have suggested limitations in executive function (EF) of children who stutter (CWS) with the evidence being more consistent in studies with preschoolers (3-6  years old) than in studies with school-aged children (6-12  years old). The purpose of the current study was to assess complex response inhibition and cognitive flexibility in school-aged CWS and their non-stuttering peers.

METHODS

Participants, 19 CWS (mean age = 7.58  years, range 6.08-9.17) and 19 age-and gender-matched children who do not stutter (CWNS; mean age = 7.58  years, range 6.08-9.33), completed a visual task consisting of three task blocks. Analyses were based on response times and error percentages during the different task blocks.

RESULTS

All participants showed expected performance-costs in task block comparisons targeting complex response inhibition and cognitive flexibility. Significant group differences were found in measures of cognitive flexibility with CWS performing slower compared to CWNS (p = 0.02). Additionally, significant block × group interactions demonstrated that CWS, compared to CWNS, slowed down more (i.e., higher performance-cost) under both complex response inhibition (p = 0.049) and cognitive flexibility task conditions (p = 0.04 for no-set-shifting and p = 0.02 for set-shifting).

CONCLUSION

These results are in line with some of the previous findings in school-aged CWS and suggest that CWS present lower performance in complex response inhibition and cognitive flexibility task conditions when compared to their non-stuttering peers.

Cognitive flexibility in younger and older children who stutter

Purpose

Recent research findings suggest possible weaknesses in cognitive flexibility (CF) in children who stutter (CWS) when compared to children who do not stutter (CWNS). Studies so far, have been conducted with either younger (3-6 years old) or older children (6-12 years old) with a variety of measures. The purpose of the present study was to investigate CF with the use of a single behavioral measure across a broader age range (4-10 years old).

Methods

Participants were 37 CWS (mean age = 6.90 years) and 37 age-and gender-matched CWNS (mean age = 6.88 years), divided in a younger (below 7 years) and older (above 7 years) age group. All participants undertook a computerized visual set-shifting task consisting of three blocks. CF was evaluated through across-and within-block comparisons of the actual response speed and accuracy values. In addition, mixing-and set-shifting-costs were evaluated based on the mean response speed and accuracy.

Results

All participants showed expected mixing-and set-shifting-costs. Only the within-block analyses yielded significant between (sub)group differences. Investigation of the block × classification group × age group interactions showed that older CWS had larger set-shifting-costs (slowed down more and made more errors) compared to older CWNS.

Conclusion

While all participants required more time during set-shifting trials, only the older CWS (7-10 years old), and not younger CWS, were slower and made more errors. This finding corroborates previous findings in CWS of a similar age and could possibly point to a role of CF in stuttering persistence.

Dual-Task Effects on Concurrent Speech Production in School-Age Children With and Without Stuttering Disorders

PURPOSE

Contemporary motor theories indicate that well-practiced movements are best performed automatically, without conscious attention or monitoring. We applied this perspective to speech production in school-age children and examined how dual-task conditions that engaged sustained attention affected speech fluency, speech rate, and language productivity in children with and without stuttering disorders.

METHOD

Participants included 47 children (19 children who stutter, 28 children who do not stutter) from 7 to 12 years of age. Children produced speech in two baseline conditions with no concurrent task and under a dual-task condition requiring sustained attention to on-screen stimuli. Measures of speech fluency, speech rate, and language productivity were obtained for each trial and compared across conditions and groups.

RESULTS

Dual-task conditions resulted in a reduction in stutter-like disfluencies relative to the initial baseline speaking condition. Effects were similar for both groups of children and could not be attributed to decreases in language productivity or a simple order effect.

CONCLUSIONS

Findings suggest that diverting attention during the process of speech production enhances speech fluency in children, possibly by increasing the automaticity of motor speech sequences. Further research is needed to clarify neurophysiological mechanisms underlying these changes and to evaluate potential clinical applications of such effects.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19945838.

Complex nonverbal response inhibition and stopping impulsivity in childhood stuttering

PURPOSE

The primary purpose of this study was to examine complex nonverbal response inhibition and stopping impulsivity in children who do (CWS) and do not stutter (CWNS).

METHOD

A total of 30 CWS and 30 CWNS between the ages of 3;1 and 6;0 (years; months) performed the Peg-Tapping Task (PTT; Diamond & Taylor, 1996; Luria, 1966), in which children were required to tap a dowel once when an examiner taps twice and vice versa. The main dependent variables were the number of practice trials, response accuracy, response latency for accurate responses, and the number of extra taps (i.e., tapping more than two times).

RESULTS

The CWS were less accurate and slower on the PTT than the CWNS, with no differences in the number of practice trials. Furthermore, the CWS, especially boys, produced more extra taps than the CWNS.

CONCLUSIONS

Findings revealed that preschool CWS have weaknesses in complex response inhibition and stopping impulsivity in the nonverbal domain compared to CWNS. Taken together, these findings along with those of previous studies indicate that CWS may have weaknesses in inhibition and impulsivity in the nonverbal domain as well as the verbal domain, suggesting a domain-general weakness.

Rhyming abilities in a dual-task in school-age children who stutter

PURPOSE

We compared school-age children who stutter (CWS) and age and gender matched control participants (CWNS) in a dual-task involving a word-level rhyming task and a tone task involving pitch decisions.

METHODS

Participants were 30 children (CWS, n = 15) between 7 and 16 years. Auditory word - picture stimuli pairs from the rhyme task were categorized into nonrhyme (e.g., bear-cart), rhyme (e.g., bear-pear), and replica (e.g., bear-bear) categories. The effort associated with managing resources in the dual-task was varied through the manipulation of stimulus onset asynchrony (SOA) between the stimuli of the two tasks. Mixed methods analyses of the response time (RT, ms) and error (%) data were conducted with Group, Category, and SOA as the fixed effects and participants as the random effect. Age and phoneme awareness skills were included in the analyses.

RESULTS

More rhyming errors and a significant positive correlation between rhyming errors and age was observed in the CWS compared to the CWNS. Compared to the CWNS, a higher percentage of rhyming errors was observed in the rhyme than the nonrhyme and replica categories in the CWS in both the SOA conditions, and this effect was influenced by age and phoneme awareness skills. Analysis of the tone task data indicated that a subgroup of CWNS with higher phoneme awareness skills showed reduced RT difference between the long and the short SOA conditions thereby suggesting higher efficiency with resource allocation for dual tasking. Task-specific differences between the CWS and CWNS are interpreted to suggest limitations in the encoding of the phonological aspects of covert speech in a dual-task.

Cognitive Flexibility and Effortful Control in School-Age Children With and Without Stuttering Disorders

Purpose This study compared attention control and flexibility in school-age children who stutter (CWS) and children who do not stutter (CWNS) based on their performance on a behavioral task and parent report. We used a classic attention-shifting paradigm that included manipulations of task goals and timing to test effects of varying demands for flexibility on switching accuracy and speed. We also examined associations between task performance, group, and relevant aspects of temperament. Method Participants included 33 children (15 CWS, 18 CWNS) between 8 and 11 years of age. Children sorted stimuli that differed on two dimensions (color and shape) based on sorting rules that varied from block to block or trial to trial. Timing manipulations included intervals of 200-, 600-, or 1,200-ms durations for critical trial components. Temperament data were obtained via the Children's Behavior Questionnaire. Results All children showed expected performance costs in response to block and trial manipulations; however, CWS were more affected by task conditions that increased demands for cognitive flexibility. Effects of interval durations also differed by group. Factor scores on the Children's Behavior Questionnaire indicated differences in effortful control between groups; however, this aspect of temperament did not mediate between-groups differences in switching performance. Conclusions Findings suggest that stuttering continues to be associated with differences in attention control and flexibility beyond the preschool years. Further research is needed to clarify how these cognitive processes shape the development of stuttering throughout childhood.

Inhibitory Control of Lexical Selection in Adults who Stutter

PURPOSE

Based on previous evidence that lexical selection may operate differently in adults who stutter (AWS) versus typically-fluent adults (TFA), and that atypical attentional processing may be a contributing factor, the purpose of this study was to investigate inhibitory control of lexical selection in AWS.

METHOD

12 AWS and 12 TFA completed two tasks. One was a picture naming task featuring High and Low Agreement object naming. Naming accuracy and reaction times (RT), and event-related potentials (ERPs) time-locked to picture onset, were recorded. Second was a flanker task featuring Congruent and Incongruent arrow arrays. Push-button accuracy and RTs, and ERPs time-locked to arrow array onset, were recorded.

RESULTS

Low Agreement pictures were named less accurately and slower than High Agreement pictures in both Groups. The magnitude of the Agreement effect on naming RTs was larger in AWS versus TFA. Delta-plot analysis revealed that the Agreement effect was positively correlated with individual differences in inhibition in TFA but not in AWS. Moreover, Low Agreement pictures elicited negative-going ERP activity relative to High Agreement pictures in both Groups. However, the scalp topography of this effect was markedly reduced in AWS versus TFA. For the Flanker task, Congruency affected push-button accuracy and RTs, and N2 amplitudes, similarly between groups.

CONCLUSIONS

Results point to a selective deficit in inhibitory control of lexical selection in AWS. Potential pathways between diminished inhibitory control of lexical selection, speech motor control and stuttering are discussed.

Visual exogenous and endogenous attention and visual memory in preschool children who stutter

PURPOSE

Attention develops gradually from infancy to the preschool years and beyond. Exogenous attention, consisting of automatic responses to salient stimuli, develops in infancy, whereas endogenous attention, or voluntary attention, begins to develop later, in the preschool years. The purpose of this study was to examine (a) exogenous and endogenous attention in young children who stutter (CWS) and children who do not stutter (CWNS) through two conditions of a visual sustained selective attention task, and (b) visual short-term memory (STM) between groups within the context of this task.

METHOD

42 CWS and 42 CWNS, ages 3;0-5;5 (years;months), were pair-matched in age, gender (31 males, 11 females per group), and socioeconomic status. Children completed a visual tracking task (Track-It Task; Fisher et al., 2013) requiring sustained selective attention and engaging exogenous and endogenous processes. Following each item, children were asked to recall the item they had tracked, as a memory check.

RESULTS

The CWS group demonstrated significantly less accuracy in overall tracking and visual memory for the tracked stimuli, compared to the CWNS group. Across groups, the children performed better in sustained selective attention when the target stimuli were more salient (the condition tapping both exogenous and endogenous attention) than when stimuli were less so (the condition tapping primarily endogenous processes).

CONCLUSIONS

Relative to peers, preschool-age CWS, as a group, display weaknesses in visual sustained selective attention and visual STM.

Cognitive Flexibility for Semantic and Perceptual Information in Developmental Stuttering

Purpose The purpose of this study was to examine cognitive flexibility for semantic and perceptual information in preschool children who stutter (CWS) and who do not stutter (CWNS). Method Participants were 44 CWS and 44 CWNS between the ages of 3;0 and 5;11 (years;months). Cognitive flexibility was measured using semantic and perceptual categorization tasks. In each task, children were required to match a target object with two different semantic or perceptual associates. Main dependent variables were reaction time and accuracy. Results The accuracy with which CWS and CWNS shifted between one semantic and perceptual representation to another was similar, but the CWS did so significantly more slowly. Both groups of children had more difficulty switching between perceptual representations than semantic ones. Conclusion CWS are less efficient (slower), though not less accurate, than CWNS in their ability to switch between different representations in both the verbal and nonverbal domains.

Associations between stuttering, comorbid conditions and executive function in children: a population-based study

Background

The aim of this study was to investigate the relationship between executive function (EF), stuttering, and comorbidity by examining children who stutter (CWS) and children who do not stutter (CWNS) with and without comorbid conditions. Data from the National Health Interview Survey were used to examine behavioral manifestations of EF, such as inattention and self-regulation, in CWS and CWNS.

Methods

The sample included 2258 CWS (girls = 638, boys = 1620), and 117,725 CWNS (girls = 57,512; boys = 60,213). EF, and the presence of stuttering and comorbid conditions were based on parent report. Descriptive statistics were used to describe the distribution of stuttering and comorbidity across group and sex. Regression analyses were to determine the effects of stuttering and comorbidity on EF, and the relationship between EF and socioemotional competence.

Results

Results point to weaker EF in CWS compared to CWNS. Also, having comorbid conditions was also associated with weaker EF. CWS with comorbidity showed the weakest EF compared to CWNS with and without comorbidity, and CWS without comorbidity. Children with stronger EF showed higher socioemotional competence. A majority (60.32%) of CWS had at least one other comorbid condition in addition to stuttering. Boys who stutter were more likely to have comorbid conditions compared to girls who stutter.

Conclusion

Present findings suggest that comorbidity is a common feature in CWS. Stuttering and comorbid conditions negatively impact EF.

Neural Processes Underlying Nonword Rhyme Differentiate Eventual Stuttering Persistence and Recovery

Purpose Phonological skills have been associated with developmental stuttering. The current study aimed to determine whether the neural processes underlying phonology, specifically for nonword rhyming, differentiated stuttering persistence and recovery. Method Twenty-six children who stutter (CWS) and 18 children who do not stutter, aged 5 years, completed an auditory nonword rhyming task. Event-related brain potentials were elicited by prime, rhyming, and nonrhyming targets. CWS were followed longitudinally to determine eventual persistence (n = 14) or recovery (n = 12). This is a retrospective analysis of data acquired when all CWS presented as stuttering. Results CWS who eventually recovered and children who do not stutter exhibited the expected rhyme effect, with larger event-related brain potential amplitudes elicited by nonrhyme targets compared to rhyme targets. In contrast, CWS who eventually persisted exhibited a reverse rhyme effect, with larger responses to rhyme than nonrhyme targets. Conclusions These findings suggest that CWS who eventually persisted are not receiving the same benefit of phonological priming as CWS who eventually recovered for complex nonword rhyming tasks. These results indicate divergent patterns of phonological processing in young CWS who eventually persisted, especially for difficult tasks with limited semantic context, and suggest that the age of 5 years may be an important developmental period for phonology in CWS. Supplemental Material https://doi.org/10.23641/asha.12682874.

Adult stuttering and attentional ability: A meta-analytic review

Purpose: The study presents the first review in which the link between attentional ability and developmental stuttering is explored. The review aimed to summarise the published research literature and provide a more conclusive understanding as to the relationship between stuttering and attention.Method: To be included in this review, the studies had to compare the attentional performance of adult people who stutter (PWS) and people who do not stutter (PWNS) over the age of 18 years with a validated psychometric instrument for measuring attentional ability. Articles were searched in four electronic databases where each of the following search terms (attention, vigilance, inhibitory, inhibition, interference, executive and processing) was cross-referenced with each of the following terms (stutter, stammer, speech disfluency and speech dysfluency). A total of 21 studies met the inclusion criteria to be submitted into a meta-analysis.Result: The results of the main meta-analysis, which included all selected studies, demonstrated that PWS had a significantly worse attentional performance as compared to PWNS. Two further meta-analyses on selective attention and dual tasking performance confirmed the latter finding. Importantly, however, the effect was not present in all studies.Conclusion: Our findings should be taken as an indication that stuttering sometimes (but not always) manifests together with poorer attentional ability, such that the identified link does not affect all PWS. These results provide support for the notion that there is a close association between stuttering and attentional ability in a subgroup of PWS, highlighting potential practical implications for stuttering treatment.

Attention, Speech-Language Dissociations, and Stuttering Chronicity

The purpose of this study was to investigate the singular and joint contributions of speech-language dissociations and attention (i.e., distractibility and attention span) to stuttering chronicity. Method Participants, aged 3;0-4;11 (years;months) at an initial visit, were classified as persisting (n = 10; 9 boys), recovered (n = 32; 23 boys), and nonstuttering (n = 28; 19 boys) based on multiple speech and language evaluations spread across 2 years. The evaluations included assessments of articulation, receptive and expressive vocabulary, and omnibus receptive and expressive language. These measures were used to identify speech-language dissociations using a correlation-based statistical approach. Attentional characteristics, which included measures of distractibility and attention span, were based on parent report. Analyses investigated between-group differences related to dissociations and attentional characteristics as well as the relation between these indices. Results There were no significant between-group differences for the persisting and recovered groups on measures of speech-language dissociations; however, the recovered group was found to exhibit less optimal attention span than the persisting group. In addition, children with dissociations exhibited less optimal distractibility and attention spans at the final time point than children without dissociations. Conclusions Present results indicate that attention is related to both stuttering chronicity and the presence of speech-language dissociations; however, they do not support the notion that dissociations are associated with stuttering persistence. These results provide novel insights into the complex nature of the association between developmental stuttering, speech-language dissociations, and attention.

The Application of EEG Mu Rhythm Measures to Neurophysiological Research in Stuttering

Deficits in basal ganglia-based inhibitory and timing circuits along with sensorimotor internal modeling mechanisms are thought to underlie stuttering. However, much remains to be learned regarding the precise manner how these deficits contribute to disrupting both speech and cognitive functions in those who stutter. Herein, we examine the suitability of electroencephalographic (EEG) mu rhythms for addressing these deficits. We review some previous findings of mu rhythm activity differentiating stuttering from non-stuttering individuals and present some new preliminary findings capturing stuttering-related deficits in working memory. Mu rhythms are characterized by spectral peaks in alpha (8-13 Hz) and beta (14-25 Hz) frequency bands (mu-alpha and mu-beta). They emanate from premotor/motor regions and are influenced by basal ganglia and sensorimotor function. More specifically, alpha peaks (mu-alpha) are sensitive to basal ganglia-based inhibitory signals and sensory-to-motor feedback. Beta peaks (mu-beta) are sensitive to changes in timing and capture motor-to-sensory (i.e., forward model) projections. Observing simultaneous changes in mu-alpha and mu-beta across the time-course of specific events provides a rich window for observing neurophysiological deficits associated with stuttering in both speech and cognitive tasks and can provide a better understanding of the functional relationship between these stuttering symptoms. We review how independent component analysis (ICA) can extract mu rhythms from raw EEG signals in speech production tasks, such that changes in alpha and beta power are mapped to myogenic activity from articulators. We review findings from speech production and auditory discrimination tasks demonstrating that mu-alpha and mu-beta are highly sensitive to capturing sensorimotor and basal ganglia deficits associated with stuttering with high temporal precision. Novel findings from a non-word repetition (working memory) task are also included. They show reduced mu-alpha suppression in a stuttering group compared to a typically fluent group. Finally, we review current limitations and directions for future research.

Effects of different attention tasks on concurrent speech in adults who stutter and fluent controls

PURPOSE

Motor theories indicate that focusing attention on well-practiced movements interferes with skilled performance; however, specific forms of attention (alerting vs. orienting vs. executive control) associated with this effect are not well understood. The present study explored this question in relation to stuttering, and examined whether dual task conditions that engaged sustained attention or working memory (WM) affected speech fluency in different ways. We also considered whether fluency changes were associated with changes in speech rate and language.

METHODS

Nineteen adults who stutter (AWS) and 20 controls produced spontaneous speech under a baseline condition and two dual task conditions: one involving a sustained attention task, the other involving WM demands.

RESULTS

Both groups produced fewer stutter-like disfluencies under dual task relative to baseline conditions and this reduction did not differ between the two dual tasks (attention vs. WM). Speech rate and language variables, which were potentially influenced by attention conditions, were not affected by dual tasks in the same way as disfluencies, and appeared to be unassociated with fluency results.

CONCLUSIONS

Findings indicate that atypical disfluencies decrease when attention is divided, even when secondary task demands are minimal, as they were in the sustained attention task. For simple secondary tasks, fluency changes do not appear to be a byproduct of slowed rate and are not accompanied by observable changes in language. These results demonstrate that simple manipulations of attention can induce measurable effects on aspects of speech production, and may be a useful tool for facilitating fluency in clinical intervention.

The Role of Executive Function in Developmental Stuttering

Developmental stuttering is a complex disorder and children who stutter form a heterogeneous group. Most contemporary researchers would agree that multiple factors, including those associated with linguistic, motor, sensory, and emotional processes, are likely involved in its development and/or maintenance. There is growing evidence, however, that cognitive processes also play a role. In this article, we briefly review behavioral and parent-report studies of executive function in children who stutter, the findings of which have generally suggested that these skills may be challenging for at least some children who stutter. We then consider how deficits in executive function could provide an explanatory account for not only the multifactorial nature of developmental stuttering but also the considerable amount of variability that exists among individuals who stutter.

Decreased occipital alpha oscillation in children who stutter during a visual Go/Nogo task

OBJECTIVE

Our goal was to discover attention- and inhibitory control-related differences in the main oscillations of the brain of children who stutter (CWS) compared to typically developed children (TDC).

METHODS

We performed a time-frequency analysis using wavelets, fast Fourier transformation (FFT) and the Alpha/Theta power ratio of EEG data collected during a visual Go/Nogo task in 7-9 year old CWS and TDC, including also the time window between consecutive tasks.

RESULTS

CWS showed significantly reduced occipital alpha power and Alpha/Theta ratio in the "resting" or preparatory period between visual stimuli especially in the Nogo condition.

CONCLUSIONS

The CWS demonstrate reduced inhibition of the visual cortex and information processing in the absence of visual stimuli, which may be related to problems in attentional gating.

SIGNIFICANCE

Occipital alpha oscillation is elementary in the control and inhibition of visual attention and the lack of occipital alpha modulation indicate fundamental differences in the regulation of visual information processing in CWS. Our findings support the view of stuttering as part of a wide-ranging brain dysfunction most likely involving also attentional and inhibitory networks.

Exogenously triggered response inhibition in developmental stuttering

PURPOSE

The purpose of the present study was to examine relations between children's exogenously triggered response inhibition and stuttering.

METHOD

Participants were 18 children who stutter (CWS; mean age = 9;01 years) and 18 children who not stutter (CWNS; mean age = 9;01 years). Participants were matched on age (±3 months) and gender. Response inhibition was assessed by a stop signal task (Verbruggen, Logan, & Stevens, 2008).

RESULTS

Results suggest that CWS, compared to CWNS, perform comparable to CWNS in a task where response control is externally triggered.

CONCLUSIONS

Our findings seem to indicate that previous questionnaire-based findings (Eggers, De Nil, & Van den Bergh, 2010) of a decreased efficiency of response inhibition cannot be generalized to all types of response inhibition.