Characteristics of speech disfluency and stuttering behaviors in 3- and 4-year-old children.

The purpose of this investigation was to quantitatively and qualitatively characterize speech disfluencies exhibited by 3- and 4-year-old children who do (CWS, N = 36) and do not (CWNS, N = 36) stutter. Five measures of speech disfluency (e.g., percentage of total, other, and stuttering-like disfluencies, mean number of repetition units, and weighted SLD measure) were used in attempts to differentiate CWS from CWNS. Similar measures of stuttering (e.g., percentage of stuttering-like disfluencies consisting of disrhythmic phonations) were used to characterize speech disfluencies in 3- and 4-year-old CWS in relation to time since stuttering onset (TSO). It was hypothesized that such measures of speech disfluency should significantly differ between CWS and CWNS, as well as 3- versus 4-year-old CWS in relation to TSO. Results indicated that 4 out of the 5 dependent measures significantly differed between CWS and CWNS, and within the CWS group there was a significant relationship between TSO and the percentage of stuttering-like disfluencies when the effects of chronological age were partialled out of the regression analyses. Furthermore, 4-year-old CWS exhibited a moderate correlation between TSO and the percentage of stuttering-like disfluencies consisting of disrhythmic phonations, whereas 3-year-old CWS exhibited no such relationship between these two variables. Findings were taken to suggest that certain measures of speech disfluency appreciably differentiate CWS from CWNS and that 4-year-old CWS exhibit changes in nonreiterative forms of stuttering as a function of time since stuttering onset.     

Articulation rate and its relationship to disfluency type, duration, and temperament in preschool children who stutter

The purpose of this study was to examine the relationship between articulation rate, frequency and duration of disfluencies of different types, and temperament in preschool children who stutter (CWS). In spontaneous speech samples from 19 CWS (mean age=3:9; years:months), we measured articulation rate, the frequency and duration of (a) sound prolongations; (b) sound-syllable repetitions; (c) single syllable whole word repetitions; and (d) clusters. Temperament was assessed with the Children's Behavior Questionnaire (Rothbart et al., 2001). There was a significant negative correlation between articulation rate and average duration of sound prolongations (p<0.01), and between articulation rate and frequency of stuttering-like disfluencies (SLDs) (p<0.05). No other relationships proved statistically significant. Results do not support models of stuttering development that implicate particular characteristics of temperament as proximal contributors to stuttering; however, this is likely due to the fact that current methods, including the ones used in the present study, do not allow for the identification of a functional relationship between temperament and speech production. Findings do indicate that for some CWS, relatively longer sound prolongations co-occur with relatively slower speech rate, which suggests that sound prolongations, across a range of durations, may represent a distinct type of SLD, not just in their obvious perceptual characteristics, but in their potential influence on overall speech production at multiple levels. LEARNING OUTCOMES: Readers will be able to describe the relationship between stuttering-like disfluencies, articulation rate and temperament in children who stutter, and discuss different measurements of articulation rate.     

Differences of articulation rate and utterance length in fluent and disfluent utterances of preschool children who stutter

Purpose

The purpose of this study was to investigate characteristics of four types of utterances in preschool children who stutter: perceptually fluent, containing normal disfluencies (OD utterance), containing stuttering-like disfluencies (SLD utterance), and containing both normal and stuttering-like disfluencies (SLD + OD utterance). Articulation rate and length of utterance were measured to seek the differences. Because articulation rate may reflect temporal aspects of speech motor control, it was predicted that the articulation rate would be different between perceptually fluent utterances and utterances containing disfluencies. The length of utterance was also expected to show different patterns.

Method

Participants were 14 preschool children who stutter. Disfluencies were identified from their spontaneous speech samples, and articulation rate in syllables per second and utterance length in syllables were measured for the four types of utterances.

Results and discussion

There was no significant difference in articulation rate between each type of utterance. Significantly longer utterances were found only in SLD + OD utterances compared to fluent utterances, suggesting that utterance length may be related to efforts in executing motor as well as linguistic planning. The SLD utterance revealed a significant negative correlation in that longer utterances tended to be slower in articulation rates. Longer utterances may place more demand on speech motor control due to more linguistic and/or grammatical features, resulting in stuttering-like disfluencies and a decreased rate.

Learning outcomes

The reader will learn about and be able to: (a) distinguish the difference between measures of overall speaking rate and articulation rate; (b) explain the theoretical and clinical trends of articulation rate in stuttering; (c) discuss how utterances containing stuttering-like disfluencies, utterances containing other disfluencies, and utterances containing both stuttering-like disfluencies and other disfluencies influence articulation rate; and (d) discuss how the length of utterances is related to disfluencies.     

The effects of self-generated synchronous and asynchronous visual speech feedback on overt stuttering frequency

PurposeRelatively recent research documents that visual choral speech, which represents an externally generated form of synchronous visual speech feedback, significantly enhanced fluency in those who stutter. As a consequence, it was hypothesized that self-generated synchronous and asynchronous visual speech feedback would likewise enhance fluency. Therefore, the purpose of this study was to investigate the effects of self-generated visual feedback (i.e., synchronous speech feedback with a mirror and asynchronous speech feedback via delayed visual feedback) on overt stuttering frequency in those who stutter.MethodEight people who stutter (4 males, 4 females), ranging from 18 to 42 years of age participated in this study. Due to the nature of visual speech feedback, the speaking task required that participants recite memorized phrases in control and experimental speaking conditions so that visual attention could be focused on the speech feedback, rather than a written passage. During experimental conditions, participants recited memorized phrases while simultaneously focusing on the movement of their lips, mouth, and jaw within their own synchronous (i.e., mirror) and asynchronous (i.e., delayed video signal) visual speech feedback.ResultsResults indicated that the self-generated visual feedback speaking conditions significantly decreased stuttering frequency (Greenhouse–Geisser p = .000); post hoc orthogonal comparisons revealed no significant differences in stuttering frequency reduction between the synchronous and asynchronous visual feedback speaking conditions (p = .2554).ConclusionsThese data suggest that synchronous and asynchronous self-generated visual speech feedback is associated with significant reductions in overt stuttering frequency. Study results were discussed relative to existing theoretical models of fluency-enhancement via speech feedback, such as the engagement of mirror neuron networks, the EXPLAN model, and the Dual Premotor System Hypothesis. Further research in the area of self-generated visual speech feedback, as well as theoretical constructs accounting for how exposure to a multi-sensory speech feedback enhances fluency, is warranted.Learning outcomes: Readers will be able to (1) discuss the multi-sensory nature of fluency-enhancing speech feedback, (2) compare and contrast synchronous and asynchronous self-generated and externally generated visual speech feedback, and (3) compare and contrast self-generated and externally generated visual speech feedback.     

Influence of stuttering variation on talker group classification in preschool children: Preliminary findings

The purpose of this study was to investigate whether variations in disfluencies of young children who do (CWS) and do not stutter (CWNS) significantly change their talker group classification or diagnosis from stutterer to nonstutterer, and vice versa. Participants consisted of seventeen 3- to 5-year-old CWS and nine 3- to 5-year-old CWNS, with no statistically significant between-group difference in chronological age (CWS: M = 45.53 months, S.D. = 8.32; CWNS: M = 47.67 months, S.D. = 6.69). All participants had speech, language, and hearing development within normal limits, with the exception of stuttering for CWS. Both talker groups participated in a series of speaking samples that varied by: (a) conversational partner [parent and clinician], (b) location [home and clinic], and (c) context [conversation and narrative]. The primary dependent measures for this study were the number of stuttering-like disfluencies (SLD) per total number of spoken words [%SLD] and the ratio of SLD to total disfluencies (TD) [SLD/TD]. The results indicated that significant variability of stuttering did not exist as a result of conversational partner or location. Changes in context, however, did impact the CWS, who demonstrated higher SLD/TD in the conversation sample versus a narrative sample. Consistent with hypotheses, CWS and CWNS were accurately identified as stutterers and nonstutterers, respectively, regardless of changes to conversational partner, location or context for the overall participant sample. Present findings were taken to suggest that during assessment, variations in stuttering frequency resulting from changes in conversational partner, location or context do not significantly influence the diagnosis of stuttering, especially for children not on the talker group classification borderline between CWS and CWNS.Learning outcomes: Readers will be able to: (1) Describe the role of variability in stuttering frequency for young children who stutter; (2) Identify three fundamental measurements of the frequency of stuttering-like and nonstuttering-like disfluencies; (3) Describe the effects of stuttering variation on talker group classification of stuttering or nonstuttering.     

Investigating the inner speech of people who stutter: evidence for (and against) the covert repair hypothesis

In their Covert Repair Hypothesis, Postma and Kolk (1993) suggest that people who stutter make greater numbers of phonological encoding errors, which are detected during the monitoring of inner speech and repaired, with stuttering-like disfluencies as a consequence. Here, we report an experiment that documents the frequency with which such errors are made. Thirty-two people who stutter (PWS) and thirty-two normally fluent controls, matched for age, gender and education, recited tonguetwisters and self-reported any errors they perceived themselves to have made. In 50% of trials the tonguetwisters were recited silently and errors reported were those detected in inner speech. Compared to controls, PWS produced significantly more word-onset and word-order errors. Crucially, this difference was found in inner as well as in overt speech. Comparison of experimenter ratings and participants' own self-ratings of their overt speech revealed similar levels of accuracy across the two groups, ruling out a suggestion that PWS were simply more sensitive to the errors they made. However, the frequency of participants' inner-speech errors was not correlated to their SSI4 scores, nor to two other measures of stuttering severity. Our findings support Postma and Kolk's contention that, when speech rate is held constant, PWS make, and therefore detect, more errors of phonological encoding. They do not, however, support the hypothesis that stuttering-like disfluencies in everyday speech stem from covert repairs of errors of phonological encoding. Learning outcomes: Readers will learn about three current psycholinguistic theories of stuttering, and how speech-errors elicited during tonguetwister recitation can be used to explore the controversies that exist surrounding: (a) Whether or not people who stutter are more prone to making language production errors; and (b) The extent to which stuttering-like disfluencies stem from covert repairs of language-production errors.     

A new antistuttering device: treatment of stuttering using bone conduction stimulation with delayed temporal feedback

OBJECTIVES: Stuttering is a communication disorder affecting approximately 1% of the adult population, some with severe manifestations. Speech therapy improves stuttering, but many do not receive enough benefit to communicate fluently. Antistuttering devices have been available for several years, but available technology has been limited in long-term success and reliability. The current study evaluates the effects of a prototype device using a modification of a currently used bone conduction hearing device with delayed auditory feedback on adult patients with significant stuttering problems. STUDY DESIGN: A prospective nonrandomized study evaluating effects of a prototype device on stuttering in adult subjects. METHODS: Ten stutterers > or=18 years of age were fit with a bone conduction device on a headband with temporal feedback delayed according to patient preference between 5 and 130 msec. Patients were asked to wear the device at least 4 hours per day for 4 weeks. Stuttering Severity Index-3 (SSI-3) tests were completed at prefit, immediate postfit, and at 2-week, 4-week, and 6-week intervals. Questionnaires were also completed at each visit. RESULTS:: Nine patients completed the entire study. A statistically significant decline in SSI-3 scores was documented from prefit compared with immediate postfit and 4 weeks follow up (P < .001) using the Tukey test method. Statistical significance was approached but not reached at 2 weeks. There was no significant difference between prefit and the 6-week follow up when patients had returned the device. Patients subjectively noted improvement in their speech and confidence using the device. CONCLUSIONS: A new antistuttering prototype using a modification of a bone conduction device with delayed temporal feedback is effective in decreasing stuttering in patients over a short time course. Further studies need to be completed to evaluate the long-term effects of the device.     

Dissecting choral speech: properties of the accompanist critical to stuttering reduction

The effects of choral speech and altered auditory feedback (AAF) on stuttering frequency were compared to identify those properties of choral speech that make it a more effective condition for stuttering reduction. Seventeen adults who stutter (AWS) participated in an experiment consisting of special choral speech conditions that were manipulated to selectively eliminate specific differences between choral speech and AAF. Consistent with previous findings, results showed that both choral speech and AAF reduced stuttering compared to solo reading. Although reductions under AAF were substantial, they were less dramatic than those for choral speech. Stuttering reduction for choral speech was highly robust even when the accompanist's voice temporally lagged that of the AWS, when there was no opportunity for dynamic interplay between the AWS and accompanist, and when the accompanist was replaced by the AWS's own voice, all of which approximate specific features of AAF. Choral speech was also highly effective in reducing stuttering across changes in speech rate and for both familiar and unfamiliar passages. We concluded that differences in properties between choral speech and AAF other than those that were manipulated in this experiment must account for differences in stuttering reduction. LEARNING OUTCOMES: The reader will be able to (1) describe differences in stuttering reduction associated with altered auditory feedback compared to choral speech conditions and (2) describe differences between delivery of a second voice signal as an altered rendition of the speakers own voice (altered auditory feedback) and alterations in the voice of an accompanist (choral speech).     

A longitudinal study of stuttering in children: a preliminary report.

The objectives of this pilot study were to establish methods for longitudinal research of stuttering in children and to provide preliminary data on the variations that occur in disfluencies during the developmental course of stuttering. Twenty-seven preschool-aged children were followed for a minimum of 2 years shortly after they began stuttering. Tape-recorded speech samples were obtained from the children at several intervals during this period. The number of various types of disfluencies was counted in the speech samples obtained in each testing period. Twenty-one children continued to be followed for varying periods of up to 12 years. Eighteen of the 27 subjects received a few speech treatment sessions during the initial period of the study, whereas 9 children did not receive direct treatment. Results indicated that for the two subgroups there was a marked deceleration over time in the mean frequency of stuttering-like disfluencies. Individual subjects' data showed considerable variability in the longitudinal development of disfluency but most subjects followed the patterns of the group means. Much of the reduction took place during the early stage of the disorder, especially near the end of the first year post-onset. There were indications that group differences between chronic and recovering stutterers become distinct by approximately 20 months post-onset.     

Real-ear output measures of ear level fluency devices

Abstract

Objective: The purpose of this study was to measure real-ear aided and saturated responses of SpeechEasy^? devices and compare responses while devices delivered altered auditory feedback (AAF) and non-altered feedback (NAF). Design: A repeated measures quasi-experimental design was employed. Study sample: Ten people fitted with completely-in-the-canal or open fit behind-the-ear devices participated. Probe microphone measures were obtained with speech, and 17 chirp stimuli presented at 75 dB and 85 dB SPL, respectively. Measurements were compared with devices delivering AAF (i.e. delayed and frequency shifted) versus NAF. Results: Maximum outputs were approximately 100–105 dB SPL in the 2000–4000 Hz range. Statistically significant differences in device SPL output as a function of device setting (AAF vs. NAF) were found for seven chirp stimuli (p <.05) when levels were sampled at points that were not temporally aligned with the output chirps but not for speech stimulus (p = .17). Device output varied across individuals and with open fit devices dominated by ear canal resonance effects. Conclusions: Real-ear aided responses were equivalent with speech input when devices delivered AAF and NAF. Real-ear saturated responses were not, however, comparable between AAF and NAF settings and may be underestimated if AAF delay is not accounted for.     

Normative disfluency data for early childhood stuttering.

Although the past 50 years of research on early childhood stuttering and normal disfluency have produced vital information on the general features of disfluent speech behavior of young children, an adequate normative reference for early stuttering does not exist. The purpose of this report is to provide such reference and to provide a basis for clinical needs of differential diagnosis of stuttering from normal disfluency. Data are presented from 90 stuttering children ages 2 to 5 within 6 months of stuttering onset and from 54 age-matched normally fluent children. Means for disfluency types are presented. No significant differences were found for gender or for age. Stuttering-like disfluencies (SLD) did differ significantly for the stuttering and fluent groups, but other disfluencies (OD) did not. A weighted SLD is defined to further clarify differences between the groups. The pattern of disfluency types for normally fluent and for mild, moderate, and severe stuttering is presented. Stuttering is shown to be qualitatively as well as quantitatively different from normal disfluency even at the earliest stages of stuttering. Clinical and research implications are discussed.     

Speaking rates, response time latencies, and interrupting behaviors of young stutterers, nonstutterers, and their mothers.

The purpose of this study was to investigate the speaking rates, interrupting behaviors, and response time latencies (RTL) produced by stuttering and nonstuttering children and their mothers, and the relationship these three paralinguistic behaviors have to children's speech disfluencies. Subjects were 13 boys who stutter (mean age = 4:0) and their mothers and 13 nonstuttering boys (mean age = 4:0) and their mothers. No significant differences were found between the two groups of children or between the two groups of mothers for any of the three paralinguistic behaviors with the exception that the mothers of nonstuttering children exhibited significantly (p < 0.01) faster rates of speech than either group of children. A strong positive correlation (r = .84) was found between stuttering children's scores on the Stuttering Severity Instrument (Riley, 1980) and the durations of the overlapping portions of their mothers' interruptions (i.e., their simultalk). Findings of this study are taken to support a facilitative demands-capacities model of conversational interaction in which mothers adjust the demands of their speaking models in response to their children's demonstrated capacities for fluent speech production.     

Difference of susceptibility to delayed auditory feedback between stutterers and nonstutterers

Forty stutterers and 40 nonstutterers were tested for susceptibility to delayed auditory feedback (DAF) while reading passages under amplified delay conditions. Susceptibility to DAF of stutterers was significantly higher than that of nonstutterers. In the nonstuttering group, men were more susceptible to DAF than women, but in the stuttering group, there was no significant difference between sexes. There was also no significant difference in DAF susceptibility between stuttering men and nonstuttering men. Nonstuttering women were least susceptible to DAF. A Susceptibility Index (SI) was found to discriminate speaker sensitivity to DAF and was interpreted to suggest that stutterers rely on auditory feedback for speech control more than nonstutterers.     

Phonological neighborhood and word frequency effects in the stuttered disfluencies of children who stutter.

PURPOSE: The purpose of this study was to examine (a) the role of neighborhood density (number of words that are phonologically similar to a target word) and frequency variables on the stuttering-like disfluencies of preschool children who stutter, and (b) whether these variables have an effect on the type of stuttering-like disfluency produced. METHOD: A 500+ word speech sample was obtained from each participant (N = 15). Each stuttered word was randomly paired with the firstly produced word that closely matched it in grammatical class, familiarity, and number of syllables/phonemes. Frequency, neighborhood density, and neighborhood frequency values were obtained for the stuttered and fluent words from an online database. RESULTS: Findings revealed that stuttered words were lower in frequency and neighborhood frequency than fluent words. Words containing part-word repetitions and sound prolongations were also lower in frequency and/or neighborhood frequency than fluent words, but these frequency variables did not have an effect on single-syllable word repetitions. Neighborhood density failed to influence the susceptibility of words to stuttering, as well as the type of stuttering-like disfluency produced. CONCLUSIONS: In general, findings suggest that neighborhood and frequency variables not only influence the fluency with which words are produced in speech, but also have an impact on the type of stuttering-like disfluency produced.     

Error monitoring in people who stutter: evidence against auditory feedback defect theories.

Several theories purport that people who stutter suffer a speech-auditory feedback defect. The disordered feedback creates the illusion that some kind of error has intruded into the speech flow. Stuttering then results from actions aimed to correct the suspected, but nonexistent, error. These auditory feedback defect theories thus predict deviant error detection performance in people who stutter during speech production. To test this prediction, subjects who stuttered and those who did not had to detect self-produced (phonemic) speech errors while speaking with normal auditory feedback and with the auditory feedback masked by white noise. The two groups did not differ significantly in error detection accuracy and speed, nor in false alarm scores. This opposes auditory feedback defect theories and suggests that the self-monitoring processes of people who stutter function normally. In a condition in which errors had to be detected in other-produced speech, i.e., while listening to a tape recording, subjects who stuttered did detect fewer errors. Whether this might signal some general phonological problem is discussed.     

HZZ-1型口吃治疗仪对46例口吃患者综合治疗的临床观察

目的总结46例口吃病例综合治疗的效果，进一步探讨口吃的治疗方法。方法采用DAF口吃治疗仪．心理辅导．语言训练相结合的治疗方法，对患者治疗前后的口吃严重程度进行比较（采用t检验），并统计治疗的有效率。结果治疗前后口吃严重程度构成有显著性差异（p〈0．01），总有效率达到98％。结论根据观察，综合治疗对于口吃患者的康复具有比较确切的疗效。     

Effects of monitoring condition and frequency-altered feedback on stuttering frequency.

The purpose of the study was to examine stuttering frequency during speaking conditions that are believed to mitigate stuttering frequency both with normal nonaltered auditory feedback (NAF) and a known fluency-enhancing feedback. Specifically, stuttering frequency was examined as a function of three monitoring conditions under NAF and frequency-altered feedback (FAF): no monitoring (i.e., speaking alone, in the absence of audio and visual recording), audiovisual monitoring (i.e., speaking alone with audiovisual recording), and audiovisual monitoring with observers (i.e., speaking with audiovisual recording in the presence of two observers). Seven adults and one adolescent who stutter served as participants. Stuttering frequency was differentially affected across monitoring conditions under each auditory feedback condition (p = .027). Post hoc analyses revealed no significant difference in stuttering frequency between the two conditions in the absence of the observers (i.e., no monitoring vs. audiovisual monitoring) under NAF (p = .45). There was, however, a significant difference in stuttering frequency for the no-monitoring and audiovisual-monitoring conditions relative to the audiovisual-monitoring-with-observers condition (p = .0002). There was no statistically significant difference in stuttering frequency across monitoring conditions under FAF (p > .05). The findings are consistent with the notion that during NAF stuttering frequency varies as a function of hierarchical socio-environmental conditions in which inanimate monitoring conditions constitute one entity. Such a relationship does not exist during FAF.     

The influence of speech stimuli contrast in cortical auditory evoked potentials

Studies about cortical auditory evoked potentials using the speech stimuli in normal hearing individuals are important for understanding how the complexity of the stimulus influences the characteristics of the cortical potential generated.ObjectiveTo characterize the cortical auditory evoked potential and the P₃ auditory cognitive potential with the vocalic and consonantal contrast stimuli in normally hearing individuals.Method31 individuals with no risk for hearing, neurologic and language alterations, in the age range between 7 and 30 years, participated in this study. The cortical auditory evoked potentials and the P₃ auditory cognitive one were recorded in the Fz and Cz active channels using consonantal (/ba/-/da/) and vocalic (/i/-/a/) speech contrasts. Design: A cross-sectional prospective cohort study.ResultsWe found a statistically significant difference between the speech contrast used and the latencies of the N₂ (p = 0.00) and P₃ (p = 0.00) components, as well as between the active channel considered (Fz/Cz) and the P₃ latency and amplitude values. These correlations did not occur for the exogenous components N₁ and P₂.ConclusionThe speech stimulus contrast, vocalic or consonantal, must be taken into account in the analysis of the cortical auditory evoked potential, N₂ component, and auditory cognitive P₃ potential.     

Stuttering, delayed auditory feedback, and linguistic rhythm

The models of stuttering and delayed auditory feedback (DAF) discussed in this paper are derived from a model of the fluent production of speech in which a rhythmic structure prespecifies the intervals between vowels of stressed syllables. The same rhythmic structure enables a prediction to be made concerning when vowels of stressed syllables will be auditorily perceived. In both stuttering and speech produced under DAF conditions, it is suggested that an incorrect prediction is made concerning when the vowel will be perceived relative to its production. The proposed model of stuttering can account for a variety of other phenomena. Finally, a preliminary model of the onset of stuttering in children is proposed.