Phonological and Semantic Contributions to Verbal Short-Term Memory in Young Children With Developmental Stuttering

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.

Linguistic aspects of stuttering: research updates on the language-fluency interface

PURPOSE

Although commonly defined as a speech disorder, stuttering interacts with the language production system in important ways. Our purpose is to summarize research findings on linguistic variables that influence stuttering assessment and treatment.

METHOD AND RESULTS

Numerous topics are summarized. First, we review research that has examined linguistic features that increase stuttering frequency and influence where it occurs. Second, we tackle the question of whether or not persons who stutter exhibit subtle language differences or deficits. Next, we explore language factors that appear to influence recovery from early stuttering in children. The final topic discusses the unique challenges inherent in differentially diagnosing stuttering in bilingual children. Clinical implications for each topic are discussed.

DISCUSSION

The article concludes with a discussion of the unique differences in the integration of language and speech demands by people who stutter, when compared to people who are typically fluent, and their clinical ramifications.

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.

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.

Lexical diversity and lexical skills in children who stutter

PURPOSE

Numerous "small N" studies of language ability in children who stutter have produced differing conclusions. We combined test and spontaneous language data from a large cohort of children who stutter (CWS) and typically fluent peers, gathered from independent laboratories across the US, to appraise a variety of lexical measures.

METHOD

Standardized receptive and expressive vocabulary test data and spontaneous language samples from 99 pairs of CWS (ages 25-100 months), and age-, gender-, and SES-matched children who do not stutter (CWNS) were compared. Language sample transcripts were analyzed with four measures of lexical diversity. Correlations between lexical diversity measures and expressive vocabulary scores were also calculated.

RESULTS

On standardized tests of both receptive and expressive vocabulary, there were significant differences between CWS and CWNS. In contrast, on spontaneous language measures of lexical diversity, CWS did not differ in their lexical diversity, across analyses, compared to CWNS. Three of the four lexical diversity analyses, MATTR, VocD, and NDW, were significantly correlated with each other.

CONCLUSIONS

We were able to confirm prior findings of relative disadvantage on standardized vocabulary tests for a very large sample of well-matched CWS. However, spontaneous language measures of lexical diversity did not distinguish the groups. This relative weakness in CWS may emerge from task differences: CWS are free to encode their own spontaneous utterances but must comply with explicit lexical prompts in standardized testing situations.

Autonomic Nervous System Response to Speech Production in Stuttering and Normally Fluent Preschool-Age Children

Purpose We studied speech-related sympathetic nervous system arousal of preschool-age children who do (CWS) and do not stutter (CWNS) and its association with children's proclivity to experience negative emotions and children's self-reported attitudes toward speaking. Method Electrodermal activity measures were collected from 32 preschool-age children while they engaged in a picture description and a nonword repetition task. Children's proclivity to experience negative emotions was assessed with a parent report questionnaire. Children's communication attitude was assessed with a self-report questionnaire. Results CWS did not differ from CWNS in their sympathetic arousal during a picture description task. However, during a more challenging nonword repetition task, preschool-age CWS had a higher sympathetic arousal level than CWNS. Although CWS were rated by their caregivers as more fearful and prone to sadness, children's tendency to experience stronger and more frequent negative emotions was not associated with their sympathetic arousal during speaking. Lastly, although CWS had a more negative communication attitude than CWNS, it was not associated with their level of sympathetic arousal during speaking. Conclusions Our findings suggest that age-appropriate social communication tasks are not inherently more stressful for preschool-age CWS and are not associated with state-related stress or anxiety that is often reported for adults who stutter. However, speaking tasks that place a higher demand on children's cognitive-linguistic system may be more taxing and challenging to preschool CWS than CWNS, leading to a higher level of arousal.

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.