Stuttering Frequency Research Articles

Personal Factors and the Overall Variability of Stuttering

Purpose: The initial diagnosis of stuttering is based on stuttering-like disfluencies. This approach fails to capture the variability in overt stuttering behaviors of persons who stutter across speaking tasks and over time. This preliminary study explored the relationships between day-to-day variability of stuttering and several commonly used self-report and behavioral outcomes used to diagnose and monitor stuttering in clinical and research settings. Method: Five adults who stutter participated in this study. All participants completed a demographic questionnaire; the Overall Assessment of the Experience of Stuttering, State, and Trait Anxiety Inventory; and the Brief Version of Unhelpful Thoughts and Beliefs About Stuttering (UTBAS), followed by six (i.e., twice weekly) online sessions where conversation and reading samples were video-recorded to determine stuttering frequency and severity. Participants also rated their stuttering severity, variability, stress, anxiety, and sleep on a 7-point Likert scale for each session. Results: No self-report measures correlated with stuttering frequency or severity measures determined at each twice-weekly online session. Positive correlations were observed between self-rated stuttering severity and stress, anxiety, and normal disfluencies. Stuttering variability across tasks and sessions was positively correlated with the one-time Overall Assessment of the Speaker's Experience of Stuttering (OASES) and UTBAS-6 scores. Conclusions: Stuttering frequency was found to vary to different degrees for individual participants, and preliminary data suggest that scores on standardized assessments such as the OASES and UTBAS-6 are predictive of stuttering variability. Objective data on stuttering frequency may not capture the entire experience of stuttering.

Comparing Speech Rate and Stuttering Frequency During Reading and Monologue Between Subjects With and Without Stuttering

Comparing Speech Rate and Stuttering Frequency During Reading and Monologue Between Subjects With and Without Stuttering

Effect of Length of Low Bi-Mora Frequency Nonwords on Stuttering Frequency in School-Age Children Who Stutter

Effect of Length of Low Bi-Mora Frequency Nonwords on Stuttering Frequency in School-Age Children Who Stutter

Executive Functions Impact the Relation Between Respiratory Sinus Arrhythmia and Frequency of Stuttering in Young Children Who Do and Do Not Stutter.

This study sought to determine whether respiratory sinus arrhythmia (RSA) and executive functions are associated with stuttered speech disfluencies of young children who do (CWS) and do not stutter (CWNS). Thirty-six young CWS and 36 CWNS were exposed to neutral, negative, and positive emotion-inducing video clips, followed by their participation in speaking tasks. During the neutral video, we measured baseline RSA, a physiological index of emotion regulation, and during video viewing and speaking, we measured RSA change from baseline, a physiological index of regulatory responses during challenge. Participants' caregivers completed the Children's Behavior Questionnaire from which a composite score of the inhibitory control and attentional focusing subscales served to index executive functioning. For both CWS and CWNS, greater decrease of RSA during both video viewing and speaking was associated with more stuttering. During speaking, CWS with lower executive functioning exhibited a negative association between RSA change and stuttering; conversely, CWNS with higher executive functioning exhibited a negative association between RSA change and stuttering. Findings suggest that decreased RSA during video viewing and speaking is associated with increased stuttering and young CWS differ from CWNS in terms of how their executive functions moderate the relation between RSA change and stuttered disfluencies.

語頭と語末のバイモーラ頻度が吃音頻度に及ぼす影響

語頭と語末のバイモーラ頻度が吃音頻度に及ぼす影響

Influence of Methylphenidate on the Frequency of Stuttering: A Randomized Controlled Trial.

Recently, a case report described a decrease in frequency of stuttering after intake of methylphenidate (MPH). This study was undertaken to investigate if this effect could again be reproduced in a population of young healthy male adult persons with developmental stuttering. A double-blind randomized crossover trial, with a 2-week washout period, including 15 Dutch-speaking young healthy persons with developmental stuttering, assessed the effects of a single dose of 20 mg MPH compared with placebo on stuttering. Dependent and 1-sample t tests were used to detect significant differences. The end point was the number of stutter moments and self-perceived improvement. MPH yielded a significant decrease in the number of stutter moments when reading and speaking (P = 0.002), which was not the case with placebo (P = 0.090). There was a significant improvement from baseline after intake of MPH as compared with placebo (P = 0.003). Self-perceived improvement with MPH was not significantly better as compared with placebo (P = 0.28). This study showed that the participants had an objective statistically significant decrease in the frequency of stuttering with MPH, and this was not the case with placebo. This was also the case for a reduction in stutter moments when reading out loud and speaking spontaneously. However, this result was not subjectively perceived by the participants.

Using Statistical Process Control Charts to Study Stuttering Frequency Variability During a Single Day

Stuttering varies between and within speaking situations. In this study, the authors used statistical process control charts with 10 case studies to investigate variability of stuttering frequency. Participants were 10 adults who stutter. The authors counted the percentage of syllables stuttered (%SS) for segments of their speech during different speaking activities over a 12-hr day. Results for each participant were plotted on control charts. All participants showed marked variation around mean stuttering frequency. However, there was no pattern of that variation consistent across the 10 participants. According to control charts, the %SS scores of half the participants were indicative of unpredictable, out-of-control systems, and the %SS scores of the other half of the participants were not. Self-rated stuttering severity and communication satisfaction correlated significantly and intuitively with the number of times participants exceeded their upper control chart limits. Control charts are a useful method to study how %SS scores might be applied to the study of stuttering variability during research and clinical practice. However, the method presents some practical problems, and the authors discuss how those problems can be solved. Solving those problems would enable researchers and clinicians to better plan, conduct, and evaluate stuttering treatments.

Correlation Between Frequency and Perceptual Severity of Stuttering in a Clinical Setting

Purpose: The purpose of this study is to further explore the relationship between the frequency of stuttering measured in percentage of syllables stuttered (%SS) and perceptual ratings of stuttering severity by the clinician and the client in a clinical setting. Method: Eight adolescent and adult participants attending a stuttering therapy program and their graduate student clinicians perceptually rated stuttering severity using a 9‐point scale. Speech samples were gathered during each therapy session for a total of 167 speech samples. Further, each sample was analyzed for %SS. A Pearson Product Moment Correlation (PPMC) was used to determine the strength and direction of correlations between %SS and perceptual ratings by the clinician and client. Results: The correlational analysis indicates significant positive correlations between perceptual severity ratings by the clinician and client as well as %SS. Correlation between perceptual ratings was stronger than the correlation between perceptual ratings and %SS. Conclusion: The strong, positive correlation between the client's self‐measurement and the clinician's perceptual measurement indicates similarities in global severity of stuttering perception. Weaker correlation between %SS and perceptual ratings indicates the need to incorporate a more holistic measure of stuttering severity. Implication and directions for future research are discussed.

Effect of Syntactic Structure on the Frequency of Stuttering in Japanese Children Who Stutter

本研究は，吃音児を対象とし，等位節構文と関係節構文を用いて，関係節構文は等位節構文よりも吃音が生じやすいのかどうか，また，関係節構文と等位節構文では吃音の生起位置が異なるのかどうかを明らかにすることを目的としたものである．対象児は6～11歳の吃音児11名であった．本研究の結果，等位節構文と関係節構文における吃音頻度に有意な差は認められなかった．また，等位節構文と関係節構文では吃音の生起位置にも顕著な違いは認められなかった．一方で，両構文ともに第1文節と第3文節は第2文節よりも有意に吃音頻度が高かった．これらの結果から，統語構造は吃音頻度や吃音生起位置に，直接的には影響を与えないことが示唆された．また，吃音頻度および吃音生起位置ともに階層関係よりも順序関係とより強く関係している可能性が示唆された．

日本語の頭子音から核母音への移行は吃音頻度に影響を与えるか?

日本語の頭子音から核母音への移行は吃音頻度に影響を与えるか?

音節量と吃音頻度 : 吃音の家族歴の有無との関係

音節量と吃音頻度 : 吃音の家族歴の有無との関係

吃音児における語頭の音節量が吃音頻度に及ぼす影響

吃音児における語頭の音節量が吃音頻度に及ぼす影響

Effect of Reading with Reversed Speech on Frequency of Stuttering in Adults

This study explored the effect of reading with reversed speech on the frequency of stuttering. Eight adults who stutter served as participants and read four 300-syllable passages while listening to three types of speech stimuli: normal speech (choral reading), reversed speech at normal speed, reversed speech at half speed, and a control condition of no auditory feedback. A repeated-measures analysis of variance showed a significant decrease in stuttering frequency in the choral reading condition but not in reversed speech at normal and half speed. However, the reversed speech at half-speed condition showed a large effect size (omega2 = 0.32). Data suggest that a forward moving speech feedback is not essential to decrease the frequency of stuttering in adults who stutter.

Stutterers' perceptions of more satisfying communication: Interaction strategies for fluent speakers

Persons who stutter must conduct their daily lives by interacting with fluent speakers. A majority of fluent speakers, however, are unaware of the communicative behaviors that can increase the frequency and severity of stutterers' dysfluencies. Moreover, extant research is scant regarding the strategies used by fluent speakers to increase interactive satisfaction with persons who stutter. This investigation addresses this void by sharing an empirical study in which stutterers offer the behaviors and strategies which they suggest result in more satisfying communicative interactions among fluent persons and stutterers.

The Main and Interactive Effect of Oral Reading Rate on the Frequency of Stuttering

Twenty-four adults participated in a 2 (group) by 3 (rate) factorial study designed to determine the main and interactive effects of speech rate during reading on the frequency of stuttering. In this regard, the participants orally read three passages, one at their normal rate, one that was 30% faster than this rate, and one that was 30% slower. Rate was controlled by means of a computer software program, and passage order and reading rate were counter-balanced. The main effect of rate was significant. There was statistically more stuttering in the fast rate condition than in either the normal or slow rate condition. However, the frequency of stuttering in the normal and the slow rate conditions was not significantly different. Analysis of the experimental data of the eight participants who stuttered the most and the eight who stuttered the least, during base-rate oral readings, evidenced the presence of an interaction between group and rate. Those who stuttered the most showed a statistically significant increase in stuttering between the slow, normal, and fast rate conditions. In contrast, there was no significant difference in frequency between any of the three conditions for the group of eight participants who stuttered the least. These findings suggest that the extent to which rate affects fluency is a function of the degree to which stuttering is displayed. This possibility warrants consideration in relation to the use of rate management procedures.

Effect of speaking into a passive resonator on stuttering frequency.

The effect on stuttering frequency of speaking into a passive resonator was investigated. Eight participants who stuttered read aloud with and without the benefit of the resonator. A statistically significant reduction of approximately 30% in stuttering frequency was observed while the participants spoke with the resonator. These and similar commercially available devices may be employed with individuals who stutter, particularly children, as a means of enhancing fluency.

Effect of Frequency-Altered Feedback on Stuttering Frequency at Normal and Fast Speech Rates

The purpose of this study was to determine the effect of the magnitude and direction of the frequency shift of frequency-altered auditory feedback (FAF) on stuttering frequency at both normal and fast speech rates. Twelve adult male and 2 adult female subjects who stutter read 10 different passages at either a normal or fast speech rate under nonaltered auditory feedback (NAF) and each of four FAF conditions in which the feedback signal was shifted: up one-half octave; up one octave; down one-half octave; and down one octave. Mean stuttering frequency for NAF was significantly higher than mean stuttering frequencies for all FAF conditions (p < 0.05). There were no statistically significant differences between the FAF conditions (p > 0.05). Subjects exhibited significantly more disfluencies under the fast speech rate condition relative to the normal speech rate condition. Future research should examine the relationship between frequency shifts of less than one-half octave and stuttering amelioration.

Effects of alterations in auditory feedback and speech rate on stuttering frequency.

This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates, Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Syntactic analysis of the spontaneous speech of normally fluent and stuttering children

The unrestricted speech of three groups each of stutterers arranged by age and age-matched controls was assessed. Analyses made on utterance length showed that this depended on age group, fluency group, and that age and fluency interacted. The frequency of usage of the various syntactic categories did not differ between the fluency groups though it did depend on the age groups. Examination of the frequency of stutterings for the stutterer groups showed that stuttering varied with syntactic category produced. This was still so after the effects of sentence length and frequency of usage of the syntactic categories were taken out as covariates. Generally speaking the more complex syntactic categories resulted in higher stuttering frequency. This relationship depends on age, with the youngest group showing most dysfluencies on the simpler syntactic categories.

Syntactic clause boundaries, speech timing, and stuttering frequency in adult stutterers : Klouda, G.V., and Cooper, W.E., University of Iowa. Language and speech, (1987) 330, 263–276.

Syntactic clause boundaries, speech timing, and stuttering frequency in adult stutterers : Klouda, G.V., and Cooper, W.E., University of Iowa. Language and speech, (1987) 330, 263–276.