The reliability of simultaneous versus individual data collection during stuttering assessment.

BACKGROUND: Speech-language pathologists often multitask in order to be efficient with their commonly large caseloads. In stuttering assessment, multitasking often involves collecting multiple measures simultaneously. AIMS: The present study sought to determine reliability when collecting multiple measures simultaneously versus individually. METHODS & PROCEDURES: Over two time periods, 50 graduate students viewed videos of four persons who stutter (PWS) and counted the number of stuttered syllables and total number of syllables uttered, and rated speech naturalness. Students were randomly assigned to one of two groups: the simultaneous group, in which all measures were gathered during one viewing; and the individual group, in which one measure was gathered per viewing. Relative and absolute intra- and inter-rater reliability values were calculated for each measure. OUTCOMES & RESULTS: The following results were notable: better intra-rater relative reliability for the number of stuttered syllables for the individual group (intraclass correlation coefficient (ICC) = 0.839) compared with the simultaneous group (ICC = 0.350), smaller intra-rater standard error of measurement (SEM) (i.e., better absolute reliability) for the number of stuttered syllables for the individual group (7.40) versus the simultaneous group (15.67), and better inter-rater absolute reliability for the total number of syllables for the individual group (88.29) compared with the simultaneous group (125.05). Absolute reliability was unacceptable for all measures across both groups. CONCLUSIONS & IMPLICATIONS: These findings show that judges are likely to be more reliable when identifying stuttered syllables in isolation than when simultaneously collecting them with total syllables spoken and naturalness data. Results are discussed in terms of narrowing the reliability gap between data collection methods for stuttered syllables, improving overall reliability of stuttering measurements, and a procedural change when implementing widely used stuttering assessment protocols. WHAT THIS PAPER ADDS: What is already known on the subject The reliability of stuttering judgments has been found to be unacceptable across a number of studies, including those examining the reliability of the most popular stuttering assessment tool, the Stuttering Severity Instrument (4th edition). The SSI-4, and other assessment applications, involve collecting multiple measures simultaneously. It has been suggested, but not examined, that collecting measures simultaneously, which occurs in the most popular stuttering assessment protocols, may result in substantially inferior reliability when compared to collecting measures individually. What this paper adds to existing knowledge The present study has multiple novel findings. First, relative and absolute intra-rater reliability were substantially better when stuttered syllables data were collected individually compared to when the same data were collected simultaneously with total number of syllables and speech naturalness data. Second, inter-rater absolute reliability for total number of syllables was also substantially better when collected individually. Third, intra-rater and inter-rater reliability were similar when speech naturalness ratings were given individually compared to when they were given while simultaneously counting stuttered and fluent syllables. What are the potential or actual clinical implications of this work? Clinicians can be more reliable when identifying stuttered syllables individually compared to when they judge stuttering along with other clinical measures of stuttering. In addition, when clinicians and researchers use current popular protocols for assessing stuttering that recommend simultaneous data collection, including the SSI-4, they should instead consider collecting stuttering event counts individually. This procedural change will lead to more reliable data and stronger clinical decision making.

Reliability of judgments of stuttering-related variables: The effect of language familiarity.

Previous studies demonstrate mixed results and some methodological limitations regarding judges' ability to reliably assess stuttering-related variables in an unfamiliar language. The present study examined intra- and inter-rater reliability for percent syllables stuttered (%SS), stuttering severity (SEV), syllables per minute (SPM), and speech naturalness (NAT) when English-speaking judges viewed speech samples in English and in a language with which they had no or minimal familiarity (Spanish). Over two time periods, 21 judges viewed eight videos of four bilingual persons who stutter. Data were analyzed for relative and absolute intra- and inter-rater reliability as well as for an effect of language on time period differences. Intra- and inter-rater relative reliability were good or excellent for all measures in both languages, with the exception of inter-rater relative reliability for NAT in both languages and %SS in Spanish. Intra-rater absolute reliability was acceptable in both languages for NAT and SEV and unacceptable in both for SPM and %SS. Inter-rater absolute reliability in both languages was unacceptable for all measures, even with judges with the same training. There was a clinically significant effect of language on %SS scores, but, despite a statistically significant effect of language for SPM and SEV, the differences were not clinically significant. Results indicate that reliability across and within languages varies by measure and is impacted by intra- vs. inter-rater reliability, relative vs. absolute reliability, and language familiarity. Modifications in training may be able to address some of the limitations found, particularly with regard to SPM and NAT.

Stuttering Frequency, Speech Rate, Speech Naturalness, and Speech Effort During the Production of Voluntary Stuttering.

PURPOSE: Voluntary stuttering techniques involve persons who stutter purposefully interjecting disfluencies into their speech. Little research has been conducted on the impact of these techniques on the speech pattern of persons who stutter. The present study examined whether changes in the frequency of voluntary stuttering accompanied changes in stuttering frequency, articulation rate, speech naturalness, and speech effort. METHOD: In total, 12 persons who stutter aged 16-34 years participated. Participants read four 300-syllable passages during a control condition, and three voluntary stuttering conditions that involved attempting to produce purposeful, tension-free repetitions of initial sounds or syllables of a word for two or more repetitions (i.e., bouncing). The three voluntary stuttering conditions included bouncing on 5%, 10%, and 15% of syllables read. Friedman tests and follow-up Wilcoxon signed ranks tests were conducted for the statistical analyses. RESULTS: Stuttering frequency, articulation rate, and speech naturalness were significantly different between the voluntary stuttering conditions. Speech effort did not differ between the voluntary stuttering conditions. Stuttering frequency was significantly lower during the three voluntary stuttering conditions compared to the control condition, and speech effort was significantly lower during two of the three voluntary stuttering conditions compared to the control condition. CONCLUSIONS: Due to changes in articulation rate across the voluntary stuttering conditions, it is difficult to conclude, as has been suggested previously, that voluntary stuttering is the reason for stuttering reductions found when using voluntary stuttering techniques. Additionally, future investigations should examine different types of voluntary stuttering over an extended period of time to determine their impact on stuttering frequency, speech rate, speech naturalness, and speech effort.

Intrajudge and Interjudge Reliability of the Stuttering Severity Instrument-Fourth Edition.

PURPOSE: The Stuttering Severity Instrument (SSI) is a tool used to measure the severity of stuttering. Previous versions of the instrument have known limitations (e.g., Lewis, 1995). The present study examined the intra- and interjudge reliability of the newest version, the Stuttering Severity Instrument-Fourth Edition (SSI-4) (Riley, 2009). METHOD: Twelve judges who were trained on the SSI-4 protocol participated. Judges collected SSI-4 data while viewing 4 videos of adults who stutter at Time 1 and 4 weeks later at Time 2. Data were analyzed for intra- and interjudge reliability of the SSI-4 subscores (for Frequency, Duration, and Physical Concomitants), total score, and final severity rating. RESULTS: Intra- and interjudge reliability across the subscores and total score concurred with the manual's reported reliability when reliability was calculated using the methods described in the manual. New calculations of judge agreement produced different values from those in the manual-for the 3 subscores, total score, and final severity rating-and provided data absent from the manual. CONCLUSIONS: Clinicians and researchers who use the SSI-4 should carefully consider the limitations of the instrument. Investigation into the multitasking demands of the instrument may provide information on whether separating the collection of data for specific variables will improve intra- and interjudge reliability of those variables.

Strategies for Teachers to Manage Stuttering in the Classroom: A Call for Research.

Purpose: This clinical focus article highlights the need for future research involving ways to assist children who stutter in the classroom. Method: The 4 most commonly recommended strategies for teachers were found via searches of electronic databases and personal libraries of the authors. The peer-reviewed evidence for each recommendation was subsequently located and detailed. Results: There are varying amounts of evidence for the 4 recommended teacher strategies outside of the classroom, but there are no data for 2 of the strategies, and minimal data for the others, in a classroom setting. That is, there is virtually no evidence regarding whether or not the actions put forth influence, for example, stuttering frequency, stuttering severity, participation, or the social, emotional, and cognitive components of stuttering in the classroom. Conclusion: There is a need for researchers and speech-language pathologists in the schools to study the outcomes of teacher strategies in the classroom for children who stutter.

Anticipation in stuttering: A theoretical model of the nature of stutter prediction.

UNLABELLED: The fact that some people who stutter have the ability to anticipate a stuttering moment is essential for several theories of stuttering and important for maximum effectiveness of many currently used treatment techniques. The "anticipation effect," however, is poorly understood despite much investigation into this phenomenon. In the present paper, we combine (1) behavioral evidence from the stuttering-anticipation literature, (2) speech production models, and (3) models of error detection to propose a theoretical model of anticipation. Integrating evidence from theories such as Damasio's Somatic Marker Hypothesis, Levelt's Perceptual Monitoring Theory, Guenther's The Directions Into Velocities of Articulators (DIVA) model, Postma's Covert Repair Hypothesis, among others, our central thesis is that the anticipation of a stuttering moment occurs as an outcome of the interactions between previous learning experiences (i.e., learnt associations between stuttered utterances and any self-experienced or environmental consequence) and error monitoring. Possible neurological mechanisms involved in generating conscious anticipation are also discussed, along with directions for future research. EDUCATIONAL OBJECTIVES: The reader will be able to: (a) describe historical theories that explain how PWS may learn to anticipate stuttering; (b) state some traditional sources of evidence of anticipation in stuttering; (c) describe how PWS may be sensitive to the detection of a stuttering; (d) state some of the neural correlates that may underlie anticipation in stuttering; and (e) describe some of the possible utilities of incorporating anticipation into stuttering interventions.

Systematic studies of modified vocalization: the effect of speech rate on speech production measures during metronome-paced speech in persons who stutter.

BACKGROUND: Metronome-paced speech results in the elimination, or substantial reduction, of stuttering moments. The cause of fluency during this fluency-inducing condition is unknown. Several investigations have reported changes in speech pattern characteristics from a control condition to a metronome-paced speech condition, but failure to control speech rate between conditions limits our ability to determine if the changes were necessary for fluency. AIMS: This study examined the effect of speech rate on several speech production variables during one-syllable-per-beat metronomic speech in order to determine changes that may be important for fluency during this fluency-inducing condition. METHODS & PROCEDURES: Thirteen persons who stutter (PWS), aged 18-62 years, completed a series of speaking tasks. Several speech production variables were compared between conditions produced at different metronome beat rates, and between a control condition and a metronome-paced speech condition produced at a rate equal to the control condition. OUTCOMES & RESULTS: Vowel duration, voice onset time, pressure rise time and phonated intervals were significantly impacted by metronome beat rate. Voice onset time and the percentage of short (30-100 ms) phonated intervals significantly decreased from the control condition to the equivalent rate metronome-paced speech condition. CONCLUSIONS & IMPLICATIONS: A reduction in the percentage of short phonated intervals may be important for fluency during syllable-based metronome-paced speech for PWS. Future studies should continue examining the necessity of this reduction. In addition, speech rate must be controlled in future fluency-inducing condition studies, including neuroimaging investigations, in order for this research to make a substantial contribution to finding the fluency-inducing mechanism of fluency-inducing conditions.

The effect of speech rate on stuttering frequency, phonated intervals, speech effort, and speech naturalness during chorus reading.

PURPOSE: This study examined the effect of speech rate on phonated intervals (PIs), in order to test whether a reduction in the frequency of short PIs is an important part of the fluency-inducing mechanism of chorus reading. The influence of speech rate on stuttering frequency, speaker-judged speech effort, and listener-judged naturalness was also examined. An added purpose was to determine if chorus reading could be further refined so as to provide a perceptual guide for gauging the level of physical effort exerted during speech production. METHODS: A repeated-measures design was used to compare data obtained during control reading conditions and during several chorus reading conditions produced at different speech rates. Participants included 8 persons who stutter (PWS) between the ages of 16 and 32 years. RESULTS: There were significant reductions in the frequency of short PIs from the habitual reading condition during slower chorus conditions, no change when speech rates were matched between habitual reading and chorus conditions, and an increase in the frequency of short PIs during chorus reading produced at a faster rate than the habitual condition. Speech rate did not have an effect on stuttering frequency during chorus reading. In general, speech effort ratings improved and naturalness ratings worsened as speech rate decreased. CONCLUSION: These results provide evidence that (a) a reduction in the frequency of short PIs is not necessary for fluency improvement during chorus reading, and (b) speech rate may be altered to provide PWS with a more appropriate reference for how physically effortful normally fluent speech production should be. Future investigations should examine the necessity of changes in the activation of neural regions during chorus reading, the possibility of defining individualized units on a 9-point effort scale, and if there are upper and lower speech rate boundaries for receiving ratings of "highly natural sounding" speech during chorus reading. LEARNING OUTCOMES: The reader will be able to: (1) describe the effect of changes in speech rate on the frequency of short phonated intervals during chorus reading, (2) describe changes to speaker-judged speech effort as speech rate changes during chorus reading, (3) and describe the effect of changes in speech rate on listener-judged naturalness ratings during chorus reading.

Systematic studies of modified vocalization: speech production changes during a variation of metronomic speech in persons who do and do not stutter.

UNLABELLED: The most common way to induce fluency using rhythm requires persons who stutter to speak one syllable or one word to each beat of a metronome, but stuttering can also be eliminated when the stimulus is of a particular duration (e.g., 1 second [s]). The present study examined stuttering frequency, speech production changes, and speech naturalness during rhythmic speech that alternated 1s of reading with 1s of silence. A repeated-measures design was used to compare data obtained during a control reading condition and during rhythmic reading in 10 persons who stutter (PWS) and 10 normally fluent controls. Ratings for speech naturalness were also gathered from naïve listeners. Results showed that mean vowel duration increased significantly, and the percentage of short phonated intervals decreased significantly, for both groups from the control to the experimental condition. Mean phonated interval length increased significantly for the fluent controls. Mean speech naturalness ratings during the experimental condition were approximately "7" on a 1-9 scale (1=highly natural; 9=highly unnatural), and these ratings were significantly correlated with vowel duration and phonated intervals for PWS. The findings indicate that PWS may be altering vocal fold vibration duration to obtain fluency during this rhythmic speech style, and that vocal fold vibration duration may have an impact on speech naturalness during rhythmic speech. Future investigations should examine speech production changes and speech naturalness during variations of this rhythmic condition. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) describe changes (from a control reading condition) in speech production variables when alternating between 1s of reading and 1s of silence, (2) describe which rhythmic conditions have been found to sound and feel the most natural, (3) describe methodological issues for studies about alterations in speech production variables during fluency-inducing conditions, and (4) describe which fluency-inducing conditions have been shown to involve a reduction in short phonated intervals.

Systematic studies of modified vocalization: effects of speech rate and instatement style during metronome stimulation.

PURPOSE: This study introduces a series of systematic investigations intended to clarify the parameters of the fluency-inducing conditions (FICs) in stuttering. METHOD: Participants included 11 adults, aged 20-63 years, with typical speech-production skills. A repeated measures design was used to examine the relationships between several speech production variables (vowel duration, voice onset time, fundamental frequency, intraoral pressure, pressure rise time, transglottal airflow, and phonated intervals) and speech rate and instatement style during metronome-entrained rhythmic speech. RESULTS: Measures of duration (vowel duration, voice onset time, and pressure rise time) differed across different metronome conditions. When speech rates were matched between the control condition and metronome condition, voice onset time was the only variable that changed. CONCLUSION: Results confirm that speech rate and instatement style can influence speech production variables during the production of fluency-inducing conditions. Future studies of normally fluent speech and of stuttered speech must control both features and should further explore the importance of voice onset time, which may be influenced by rate during metronome stimulation in a way that the other variables are not.

Measurement of phonated intervals during four fluency-inducing conditions.

PURPOSE: Previous investigations of persons who stutter have demonstrated changes in vocalization variables during fluency-inducing conditions (FICs). A series of studies has also shown that a reduction in short intervals of phonation, those from 30 to 200 ms, is associated with decreased stuttering. The purpose of this study, therefore, was to test the hypothesis that the distribution of phonated intervals (PIs) should change during 4 of the most well-known FICs. METHOD: A repeated-measures design was used to explore the relationship between PIs and stuttering during 4 FICs: chorus reading, prolonged speech, singing, and rhythmic stimulation. Most conditions were conducted at 2 different speech rates. The distribution of PIs was measured during these conditions and was compared with PI distributions obtained during control conditions. RESULTS: Overall PI distributions were significantly different during all 4 FICs, as compared with control conditions. PIs in the range of 30-150 ms were reduced across all FICs, at all speech rates. CONCLUSION: These results provide further evidence of the importance of phonation variables to (a) our understanding of how FICs may operate and (b) the treatment of stuttering. These findings, along with previous studies that showed how purposefully reducing the number of short PIs resulted in the elimination of stuttering, suggest that treatment programs based on prolonged speech-or PIs, in particular-may benefit from emphasizing a reduction in the number of short PIs and a simultaneous increase in the number of longer PIs.

Stuttering treatment research 1970-2005: I. Systematic review incorporating trial quality assessment of behavioral, cognitive, and related approaches.

PURPOSE: To complete a systematic review, with trial quality assessment, of published research about behavioral, cognitive, and related treatments for developmental stuttering. Goals included the identification of treatment recommendations and research needs based on the available high-quality evidence about stuttering treatment for preschoolers, school-age children, adolescents, and adults. METHOD: Multiple readers reviewed 162 articles published between 1970 and 2005, using a written data extraction instrument developed as a synthesis of existing standards and recommendations. Articles were then assessed using 5 methodological criteria and 4 outcomes criteria, also developed from previously published recommendations. RESULTS: Analyses found 39 articles that met at least 4 of the 5 methodological criteria and were considered to have met a trial quality inclusion criterion for the purposes of this review. Analysis of those articles identified a range of stuttering treatments that met speech-related and/or social, emotional, or cognitive outcomes criteria. CONCLUSIONS: Review of studies that met the trial quality inclusion criterion established for this review suggested that response-contingent principles are the predominant feature of the most powerful treatment procedures for young children who stutter. The most powerful treatments for adults, with respect to both speech outcomes and social, emotional, or cognitive outcomes, appear to combine variants of prolonged speech, self-management, response contingencies, and other infrastructural variables. Other specific clinical recommendations for each age group are provided, as are suggestions for future research.

Stuttering treatment research 1970-2005: II. Systematic review incorporating trial quality assessment of pharmacological approaches.

PURPOSE: To complete a systematic review, incorporating trial quality assessment, of published research about pharmacological treatments for stuttering. Goals included the identification of treatment recommendations and research needs based on the available high-quality evidence. METHOD: Multiple readers reviewed 31 articles published between 1970 and 2005, using a written data extraction instrument developed as a synthesis of existing standards and recommendations. Articles were then assessed using 5 methodological criteria and 4 outcomes criteria, also developed from previously published recommendations. RESULTS: None of the 31 articles met more than 3 of the 5 methodological criteria (M = 1.74). Four articles provided data to support a claim of short-term improvement in social, emotional, or cognitive variables. One article provided data to show that stuttering frequency was reduced to less than 5%, and 4 additional articles provided data to show that stuttering may have been reduced by at least half. Among the articles that met the trial quality inclusion criterion for the second stage of this review, none provided uncomplicated positive reports. CONCLUSIONS: None of the pharmacological agents tested for stuttering have been shown in methodologically sound reports to improve stuttering frequency to below 5%, to reduce stuttering by at least half, or to improve relevant social, emotional, or cognitive variables. These findings raise questions about the logic supporting the continued use of current pharmacological agents for stuttering.

The Stuttering Treatment Research Evaluation and Assessment Tool (STREAT): evaluating treatment research as part of evidence-based practice.

PURPOSE: This article presents, and explains the issues behind, the Stuttering Treatment Research Evaluation and Assessment Tool (STREAT), an instrument created to assist clinicians, researchers, students, and other readers in the process of critically appraising reports of stuttering treatment research. METHOD: The STREAT was developed by combining and reorganizing previously published recommendations about the design and conduct of stuttering treatment research. CONCLUSIONS: If evidence-based practice is to be widely adopted as the basis for stuttering assessment and treatment, procedures must be developed and distributed that will allow students, clinicians, and other readers without specialized knowledge of research design to critically appraise treatment research reports. The STREAT is intended to be such an instrument: It represents the consensus of previous methodological recommendations; it is consistent with and complements existing recommendations in evidence-based medicine and in the broader science of treatment outcome evaluation; and it is formatted into a single instrument for ease of use.

Low-level static lip force control does not alter vibrotactile detection thresholds in the human orofacial system.

Mechanosensation associated with precise orofacial force regulation may contribute considerably to processes associated with perception, proprioception and sensorimotor control due to the direct coupling between orofacial skin and the underlying musculature. Recent investigations have demonstrated that dynamic, low-level lip force control is capable of modulating vibrotactile detection thresholds of the lips in a frequency-dependent manner. What is not known is whether the mode of motor control (static versus dynamic) may represent an important control variable in the expression of these perceptual threshold changes. The purpose of this study was to assess lower-lip (LL) vibratory detection thresholds from adult subjects during the simultaneous performance of a visually regulated, static lip motor control task. Vibrotactile inputs were delivered to the right LL vermilion at test frequencies of 5, 10, 50 and 150 Hz. Psychophysical detection was performed simultaneously during a no-force baseline condition and an active static force control task performed with the lip musculature. Subjects used their analog lip force signal to maintain a static lip force posture by visually tracking a steady-state force target calibrated to a 0.1 N load. Both signals were displayed in real time on a monitor. Results suggest that, unlike dynamic lip motor control, low-level, static lip force regulation is not effective in altering LL vibrotactile detection thresholds to any test frequency. These findings are discussed in relation to published reports of movement-related sensory gating in orofacial and limb systems and the possible significance this phenomenon may have for perception and proprioception in the orofacial system.