Effect of extended exposure to frequency-altered feedback on stuttering during reading and monologue

A Case Study of Mediated Learning, Delayed Auditory Feedback, and Motor Repatterning to Reduce Stuttering

A case study of DW, an 11-yr. old monolingual, English-speaking boy who exhibits stuttering, language delay, and ADHD is presented. DW experienced only limited improvement during stuttering therapy received in public schools, according to parents and the public school clinician. The purpose of this case study was to assess whether fluency treatment which incorporated Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning would enhance progress. Therapy was delivered in two treatments, with each treatment being 5 wk. of intense therapy, separated by one year. Treatment 1 of combined Mediated Learning and Delayed Auditory Feedback yielded improvement in fluency, judged by parents and the teacher to be clinically significant. The improved fluency was maintained for one year when DW was pretested for participation in Treatment 2, which combined Mediated Learning, Delayed Auditory Feedback, and Speech Motor Repatterning Exercises. As no conclusions are possible, further study is needed.

Linguistic and emotional-valence characteristics of reading passages for clinical use and research

PURPOSE

Fluency assessment in people who stutter (PWS) includes reading aloud passages. There is little information on properties of these passages that may affect reading performance: emotional valance, arousal, word familiarity and frequency and passage-readability. Our first goal was to present an extensive examination of these factors in three commonly used (“traditional”) passages. The second goal was to compare a traditional passage to a new passage, designed to minimize the impact of these properties.

METHODS

Content words were rated (129 participants) on arousal, valence and familiarity. Other linguistic features were analyzed based on available datasets. This information was used to assess traditional passages, and to construct a new well-balanced passage, made of neutral, low-arousal and highly-familiar words. Readability for all passages was tested using formula-based and CLOZE tests (31 participants). Finally, 26 PWS were evaluated on fluency comparing the commonly used “Rainbow” passage with the novel one.

RESULTS

The three traditional passages contain a share of emotionally valenced (22-34%), high arousal (15-18%), lower familiarity (6-8%) and polysyllabic (5-9%) content words. Readability was highest for the novel passage (on formula-based scales). Average disfluencies percent for the Rainbow and our novel passage were not significantly different. Yet half of the individuals in this sample showed a large difference between the two passages.

CONCLUSION

We provide detailed information on potential sources of variance using the traditional passages. Knowledge about these characteristics can inform clinical practice (and research). We suggest a combined procedure, using more than one passage to assess stuttering in individual cases.

Non-pharmacological treatments for stuttering in children and adults: a systematic review and evaluation of clinical effectiveness, and exploration of barriers to successful outcomes

BACKGROUND

Despite many years of research, there is no certainty regarding the cause of stuttering. Although numerous interventions have been developed, a broad-based systematic review across all forms of intervention for adults and children was needed including views and perceptions of people who stutter.

OBJECTIVE

The aims of the study were to report the clinical effectiveness of interventions for people who stutter (or clutter), to examine evidence regarding the views of people who stutter and the views of professionals regarding interventions.

DATA SOURCES

A systematic review of quantitative and qualitative literature was carried out between August 2013 and April 2014. The following electronic databases were searched: (1) MEDLINE, (2) EMBASE, (3) The Cochrane Library (including The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, Health Technology Assessment Database and NHS Economic Evaluations Database), (4) PsycINFO, (5) Science Citation Index, (6) Social Science Citation Index, (7) Cumulative Index to Nursing and Allied Health Literature, (8) ASSIA, (9) Linguistics and Language Behavior Abstracts, (10) Sociological Abstracts and (11) the EPPI Centre. Reference lists of included papers and other reviews were screened and also key journals in the subject area were hand-searched.

REVIEW METHODS

The searches aimed to identify (1) evidence of clinical effectiveness in populations of pre-school children, school-aged children, adolescents and adults, and (2) data relating to perceptions of barriers and facilitators to intervention clinical effectiveness among staff and people who stutter. A metasynthesis of the two linked elements via development of a conceptual model was also carried out to provide further interpretation of the review findings.

RESULTS

A systematic search of the literature identified a large number of potentially relevant studies. Of these, 111 studies examining the clinical effectiveness of interventions, 25 qualitative papers and one mixed-methods paper met the criteria for inclusion in this review. Review of the effectiveness literature indicated evidence of positive outcomes across all types of interventions. Virtually all evidence we identified reported at least some positive effect for some participants. However, there was evidence of considerable individual variation in outcome for study participants. The qualitative literature highlighted the need for programmes to be tailored to individual need with variation at the levels of the intervention, the individual and interpersonal/social elements. Metasynthesis of the data highlighted the complexity of elements that need to be considered in evaluation of long-term impacts following stuttering interventions.

LIMITATIONS

Around two-thirds of the studies were considered to be at higher risk of bias. The heterogeneous nature and variability in outcomes meant that we were unable to complete a meta-analysis.

CONCLUSIONS

Although much of the evidence we identified was from studies at risk of bias, it is suggested that most available interventions for stuttering may be of benefit to at least some people who stutter. There is a requirement for greater clarity regarding what the core outcomes following stuttering intervention should be and also enhanced understanding of the process whereby interventions effect change. Further analysis of those for whom interventions have not produced a significant benefit may provide additional insights into the complex intervention-outcomes pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004861.

The state of the art in non-pharmacological interventions for developmental stuttering. Part 1: a systematic review of effectiveness

BACKGROUND

The growing range of available treatment options for people who stutter presents a challenge for clinicians, service managers and commissioners, who need to have access to the best available treatment evidence to guide them in providing the most appropriate interventions. While a number of reviews of interventions for specific populations or a specific type of intervention have been carried out, a broad-based systematic review across all forms of intervention for adults and children was needed to provide evidence to underpin future guidelines, inform the implementation of effective treatments and identify future research priorities.

AIMS

To identify and synthesize the published research evidence on the clinical effectiveness of the broad range of non-pharmacological interventions for the management of developmental stuttering.

METHODS & PROCEDURES

A systematic review of the literature reporting interventions for developmental stuttering was carried out between August 2013 and April 2014. Searches were not limited by language or location, but were restricted by date to studies published from 1990 onwards. Methods for the identification of relevant studies included electronic database searching, reference list checking, citation searching and hand searching of key journals. Appraisal of study quality was performed using a tool based on established criteria for considering risk of bias. Due to heterogeneity in intervention content and outcomes, a narrative synthesis was completed.

MAIN CONTRIBUTION

The review included all available types of intervention and found that most may be of benefit to at least some people who stutter. There was evidence, however, of considerable individual variation in response to these interventions. The review indicated that effects could be maintained following all types of interventions (although this was weakest with regard to feedback and technology interventions).

CONCLUSIONS

This review highlights a need for greater consensus with regard to the key outcomes used to evaluate stuttering interventions, and also a need for enhanced understanding of the process whereby interventions effect change. Further analysis of the variation in effectiveness for different individuals or groups is needed in order to identify who may benefit most from which intervention.

Event- and interval-based measurement of stuttering: a review

BACKGROUND

Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based absolute reliability data or to compute the agreement between the two methodologies in terms of inter-judge, intra-judge and accuracy (i.e., correspondence between raters' scores and an established criterion).

AIMS

To provide a review related to reproducibility of event-based and time-interval measurement, and to verify the effect of methodological factors (training, experience, interval duration, sample presentation order and judgment conditions) on agreement of time-interval measurement; in addition, to determine if it is possible to quantify the agreement between the two methodologies

METHODS & PROCEDURES

The first two authors searched for articles on ERIC, MEDLINE, PubMed, B-on, CENTRAL and Dissertation Abstracts during January-February 2013 and retrieved 495 articles. Forty-eight articles were selected for review. Content tables were constructed with the main findings.

MAIN CONTRIBUTION

Articles related to event-based measurements revealed values of inter- and intra-judge greater than 0.70 and agreement percentages beyond 80%. The articles related to time-interval measures revealed that, in general, judges with more experience with stuttering presented significantly higher levels of intra- and inter-judge agreement. Inter- and intra-judge values were beyond the references for high reproducibility values for both methodologies. Accuracy (regarding the closeness of raters' judgements with an established criterion), intra- and inter-judge agreement were higher for trained groups when compared with non-trained groups. Sample presentation order and audio/video conditions did not result in differences in inter- or intra-judge results. A duration of 5 s for an interval appears to be an acceptable agreement. Explanation for high reproducibility values as well as parameter choice to report those data are discussed.

CONCLUSIONS & IMPLICATIONS

Both interval- and event-based methodologies used trained or experienced judges for inter- and intra-judge determination and data were beyond the references for good reproducibility values. Inter- and intra-judge values were reported in different metric scales among event- and interval-based methods studies, making it unfeasible to quantify the agreement between the two methods.

Stuttering inhibition via altered auditory feedback during scripted telephone conversations

BACKGROUND

Overt stuttering is inhibited by approximately 80% when people who stutter read aloud as they hear an altered form of their speech feedback to them. However, levels of stuttering inhibition vary from 60% to 100% depending on speaking situation and signal presentation. For example, binaural presentations of delayed auditory feedback (DAF) and frequency-altered feedback (FAF) have been shown to reduce stuttering by approximately 57% during scripted telephone conversations.

AIMS

To examine stuttering frequency under monaural auditory feedback with one combination of DAF with FAF (COMBO-2) and two combinations of DAF with FAF (COMBO-4) during scripted telephone conversations.

METHODS & PROCEDURES

Nine adult participants who stutter called 15 local businesses during scripted telephone conversations; each condition consisted of five randomized telephone calls. Conditions consisted of (1) baseline (i.e. non-altered feedback), (2) COMBO-2 (i.e. 50-ms delay with a half octave spectral shift up), and (3) COMBO-4 (i.e. 200-ms delay and a half octave spectral shift down in addition to the COMBO-2). Participants wore a supra-aural headset with a dynamic condenser microphone while holding a receiver to their contralateral ear when making telephone calls.

OUTCOMES & RESULTS

Stuttering was significantly reduced during both altered auditory feedback (AAF) conditions by approximately 65%. Furthermore, a greater reduction in stuttering was revealed during the COMBO with four effects (74%) as compared with the COMBO with two effects (63%).

CONCLUSIONS & IMPLICATIONS

Results from the current study support prior research reporting decreased stuttering under AAF during scripted telephone conversations. Findings that stuttering was significantly reduced to a greater extent under the COMBO with four effects condition suggest that second signals reduce stuttering along a continuum. Additionally, findings support prior research results of decreased stuttering frequency under AAF during hierarchically difficult speaking situations. Clinical application of these findings may be that people who stutter can use specific software or smartphone applications that produce second speech signals to inhibit stuttering frequency effectively during telephone conversations.

The SpeechEasy device in stuttering and nonstuttering adults: fluency effects while speaking and reading

The SpeechEasy is an electronic device designed to alleviate stuttering by manipulating auditory feedback via time delays and frequency shifts. Device settings (control, default, custom), ear-placement (left, right), speaking task, and cognitive variables were examined in people who stutter (PWS) (n=14) compared to controls (n=10). Among the PWS there was a significantly greater reduction in stuttering (compared to baseline) with custom device settings compared to the non-altered feedback (control) condition. Stuttering was reduced the most during reading, followed by narrative and conversation. For the conversation task, stuttering was reduced more when the device was worn in the left ear. Those individuals with a more severe stuttering rate at baseline had a greater benefit from the use of the device compared to individuals with less severe stuttering. Our results support the view that overt stuttering is associated with defective speech-language monitoring that can be influenced by manipulating auditory feedback.

Revisiting Bloodstein's Anticipatory Struggle Hypothesis from a psycholinguistic perspective: a Variable Release Threshold hypothesis of stuttering

This paper reviews Bloodstein's (1975) Anticipatory Struggle Hypothesis of stuttering, identifies its weaknesses, and proposes modifications to bring it into line with recent advances in psycholinguistic theory. The review concludes that the Anticipatory Struggle Hypothesis provides a plausible explanation for the variation in the severity of stuttered disfluencies across speaking situations and conversation partners. However, it fails to explain the forms that stuttered disfluencies characteristically take or the subjective experience of loss of control that accompanies them. The paper then describes how the forms and subjective experiences of persistent stuttering can be accounted for by a threshold-based regulatory mechanism of the kind described in Howell's (2003) revision of the EXPLAN hypothesis. It then proposes that shortcomings of both the Anticipatory Struggle and EXPLAN hypotheses can be addressed by combining them together to create a 'Variable Release Threshold' hypothesis whereby the anticipation of upcoming difficulty leads to the setting of an excessively high threshold for the release of speech plans for motor execution. The paper also reconsiders the possibility that two stuttering subtypes exist: one related to formulation difficulty and other to difficulty initiating motor execution. It concludes that research findings that relate to the one may not necessarily apply to the other.

LEARNING OUTCOMES

After reading this article, the reader will be able to: (1) summarize the key strengths and weaknesses of Bloodstein's Anticipatory Struggle Hypothesis; (2) describe two hypothesized mechanisms behind the production of stuttered disfluencies (tension and fragmentation & release threshold mechanisms); and (3) discuss why the notion of anticipation is relevant to current hypotheses of stuttering.

Individual variability in delayed auditory feedback effects on speech fluency and rate in normally fluent adults

PURPOSE

Delayed auditory feedback (DAF) is known to induce stuttering-like disfluencies (SLDs) and cause speech rate reductions in normally fluent adults, but the reason for speech disruptions is not fully known, and individual variation has not been well characterized. Studying individual variation in susceptibility to DAF may identify factors that predispose an individual to be more or less dependent on auditory feedback.

METHOD

Participants were 62 normally fluent adults. Each participant performed a spontaneous speech task in 250-ms DAF and amplified nondelayed auditory feedback (NAF) conditions. SLDs, other disfluencies (ODs), speech errors (SEs), and articulation rate (AR) were measured under each condition.

RESULTS

In the DAF condition, SLDs and SEs significantly increased, and AR decreased. Sex had a limited effect in that men exhibited higher rates of ODs and faster AR than women. More important, parametric cluster analysis identified that 2- and 3-subgroup solutions reveal important variation that differentiates tendencies toward disfluency changes and rate reduction under DAF, which are theoretically and empirically preferred to a single-group solution.

CONCLUSION

Individual variability in response to DAF may be accounted for by subgroups of individuals. This suggests that certain normally fluent individuals could be more dependent on intact feedback to maintain fluency.

Immediate effects of AAF devices on the characteristics of stuttering: a clinical analysis

The present study investigated the immediate effects of altered auditory feedback (AAF) and one Inactive Condition (AAF parameters set to 0) on clinical attributes of stuttering during scripted and spontaneous speech. Two commercially available, portable AAF devices were used to create the combined delayed auditory feedback (DAF) and frequency altered feedback (FAF) effects. Thirty adults, who stutter, aged 18-68 years (M=36.5; SD=15.2), participated in this investigation. Each subject produced four sets of 5-min of oral reading, three sets of 5-min monologs as well as 10-min dialogs. These speech samples were analyzed to detect changes in descriptive features of stuttering (frequency, duration, speech/articulatory rate, core behaviors) across the various speech samples and within two SSI-4 (Riley, 2009) based severity ratings. A statistically significant difference was found in the frequency of stuttered syllables (%SS) during both Active Device conditions (p=.000) for all speech samples. The most sizable reductions in %SS occurred within scripted speech. In the analysis of stuttering type, it was found that blocks were reduced significantly (Device A: p=.017; Device B: p=.049). To evaluate the impact on severe and mild stuttering, participants were grouped into two SSI-4 based categories; mild and moderate-severe. During the Inactive Condition those participants within the moderate-severe group (p=.024) showed a statistically significant reduction in overall disfluencies. This result indicates, that active AAF parameters alone may not be the sole cause of a fluency-enhancement when using a technical speech aid.

EDUCATIONAL OBJECTIVES

The reader will learn and be able to describe: (1) currently available scientific evidence on the use of altered auditory feedback (AAF) during scripted and spontaneous speech, (2) which characteristics of stuttering are impacted by an AAF device (frequency, duration, core behaviors, speech & articulatory rate, stuttering severity), (3) the effects of an Inactive Condition on people who stutter (PWS) falling into two severity groups, and (4) how the examined participants perceived the use of AAF devices.

Análise sistemática da efetividade do uso da alteração do feedback auditivo para a redução da gagueira

OBJETIVO: Realizar uma revisão sistemática de pesquisas relacionadas aos efeitos da alteração do feedback auditivo sobre a fluência da fala em pessoas com gagueira. ESTRATÉGIA DE PESQUISA: Foram seguidos os preceitos do Cochrane Handbook: formulação da pergunta inicial (tema a ser pesquisado), localização e seleção dos estudos (base de dados PubMed) e compatibilização entre os pesquisadores (visando minimizar possíveis perdas de citações). CRITÉRIOS DE SELEÇÃO: Foram excluídas: citações em línguas que não fossem o Inglês, citações que não permitiram o acesso ao texto completo, citações repetidas por sobreposição das palavras-chave utilizadas, pesquisas realizadas exclusivamente com indivíduos fluentes; estudos de caso; revisões de literatura; cartas ao editor e textos que não se relacionavam diretamente ao tema. Desta forma, foram analisados os textos que efetivamente se relacionavam às pesquisas de tratamento com delayed auditory feedback (DAF)e o frequency-altered feedback (FAF). ANÁLISE DOS DADOS: Os dados foram analisados quanto aos indicadores da pesquisa e quanto aos marcadores de qualidade dos estudos. RESULTADOS: Os resultados indicaram que o uso dos dispositivos de alteração do feedback auditivo na redução do número de eventos de gagueira ainda não tem suporte robusto em sua aplicabilidade. A variabilidade de método não permite uma resposta ou uma tendência de resposta que possa ser considerada consistente sobre a eficácia do dispositivo. CONCLUSÃO: Embora as limitações apontadas nos estudos impeçam generalizações sobre a eficácia do uso do dispositivo para a redução da gagueira, essas mesmas limitações são recursos importantes para o planejamento de pesquisas futuras.

An experimental investigation of the effect of altered auditory feedback on the conversational speech of adults who stutter

PURPOSE

To investigate the impact on percentage of syllables stuttered of various durations of delayed auditory feedback (DAF), levels of frequency-altered feedback (FAF), and masking auditory feedback (MAF) during conversational speech.

METHOD

Eleven adults who stuttered produced 10-min conversational speech samples during a control condition and under 4 different combinations of DAF, FAF, and MAF. Participants also read aloud in a control condition with DAF and FAF.

RESULTS

A statistically significant difference was found between the NAF conversation condition and the 4 combined altered auditory feedback (AAF) conditions. No statistically significant differences in percentage of syllables stuttered were found in conversation or reading between the control conditions and the FAF/DAF or MAF conditions. The analysis of individual participants' data showed highly individual responsiveness to different conditions.

CONCLUSIONS

Participants' varying responses to differing AAF settings likely accounted for the failure to find group differences between conditions. These results suggest that studies that use standard DAF and FAF settings for all participants are likely to underestimate any AAF effect. It is not yet possible to predict who will benefit from AAF devices in everyday situations and the extent of those benefits.

A survey of Australian adult users of altered auditory feedback devices for stuttering: Use patterns, perceived effectiveness and satisfaction

PURPOSE

Small portable devices that provide delayed auditory feedback (DAF) and/or frequency altered feedback (FAF) have been developed and marketed to clinicians and people who stutter as fluency enhancing aids for use in everyday speaking situations. The literature contains many laboratory-based reports about the impact of altered auditory feedback (AAF) on the speech of people who stutter but few reports about its use in everyday speaking situations. This paper investigates use patterns and perceptions of the effectiveness and satisfaction with AAF devices.

METHODS

The current study surveys 14 Australian AAF users.

RESULTS

The survey responses revealed varied opinions about AAF devices and their use and effectiveness in everyday speaking situations. Opinions were somewhat related to the type of device used.

CONCLUSIONS

The results of this study provide some important directions for future research. In particular there is need to investigate the effectiveness of AAF devices when used in conjunction with other traditional treatments.

Investigations of the impact of altered auditory feedback in-the-ear devices on the speech of people who stutter: One-year follow-up

PURPOSE

This study examined objective and subjective measures of the effect of a self-contained ear-level device delivering altered auditory feedback (AAF) for those who stutter 12 months following initial fitting with and without the device.

METHOD

Nine individuals with developmental stuttering participated. In Experiment 1, the proportion of stuttering was examined during reading and monologue. A self-report inventory inquiring about behaviour related to struggle, avoidance and expectancy associated with stuttering was examined in Experiment 2. In Experiment 3, naïve listeners rated the speech naturalness of speech produced by the participants during reading and monologue.

RESULTS

The proportions of stuttering events were significantly ( p < 0.05) reduced at initial fitting and remained so 12 months post follow-up. After using the device for 12 months, self-reported perception of struggle, avoidance and expectancy were significantly (p < 0.05) reduced relative to pre-fitting. Naïve listeners rated the speech samples produced by those who stutter while wearing the device significantly more natural sounding than those produced without the device for both reading and monologue (p < 0.0001).

CONCLUSIONS

These findings support the notion that a device delivering AAF is a viable therapeutic alternative in the treatment of stuttering.

Effects of the SpeechEasy on objective and perceived aspects of stuttering: a 6-month, phase I clinical trial in naturalistic environments

PURPOSE

Effects of the SpeechEasy when used under extraclinical conditions over several months were investigated. Primary purposes were to help establish Phase I level information about the therapeutic utility of the SpeechEasy and to compare those results with previous findings obtained in laboratory and clinical settings.

METHOD

Eleven adults who stutter participated. A nonrandomized ABA group design was utilized. Speech samples were collected every 2 weeks in extraclinical environments. Qualitative data were collected through weekly written logs and an exit questionnaire.

RESULTS

Group analyses revealed a statistically significant effect of the SpeechEasy immediately postfitting but no treatment effect across 4 months' time. Individual responses varied greatly with regard to stuttering frequency and subjective impressions. Relatively more stuttering reduction occurred during oral reading than during formulated speech.

CONCLUSIONS

Based on this protocol, Phase II trials are not indicated. However, positive individual responses and self-reports suggest some clinical utility for the SpeechEasy. The use of more challenging sampling procedures strengthened external validity and captured more modest altered auditory feedback effects compared with those previously reported in laboratory settings. Device use coincided more so with positive subjective impressions than with measurable fluency improvement, highlighting challenges facing clinicians when implementing principles of evidence-based practice, including client-based preferences.

Effects of altered auditory feedback (AAF) on stuttering frequency during monologue speech production

The present study investigated the immediate effects of eight altered auditory feedback (AAF) parameters on stuttering frequency during monologue speech production on two occasions. One of the modern commercially available portable anti-stuttering devices, "The Pocket Speech Lab" (Casa Futura Technologies) was used in the study to produce the auditory feedback alterations. Six types of combined delayed auditory feedback (DAF) and frequency shifted auditory feedback (FAF) and two types of DAF alone were tested for eight participants aged 16-55 years, with stuttering severity ranging from mild to severe. The present study found that AAF is an effective means to reduce stuttering frequency during monologue speech production. All eight AAF experimental conditions reduced stuttering frequency, however, there was substantial variability in the stuttering reduction effect across experimental conditions and across participants. There was also instability in stuttering reduction across the two testing sessions. On average, a 75 ms time delay on its own and a combination of the 75 ms time delay and a half octave downward frequency shift were found to be more effective than other combinations of AAF parameters that were investigated.

EDUCATIONAL OBJECTIVES

After reading this paper, the reader should be able to (1) summarize the research investigating the effect of altered auditory feedback on stuttering frequency during monologue speech production; (2) describe the stuttering reduction effect of the eight parameters of AAF tested during monologue speech production; and (3) discuss the possible clinical implications of the use of AAF for stuttering treatment.

The effect of frequency altered feedback on stuttering duration and type

PURPOSE

The effect of frequency altered feedback (FAF) on stuttering type (i.e., prolongation, repetition, or silent block) and stuttering duration (i.e., average duration of stuttering event and total stuttering time) was examined.

METHOD

Retrospective analyses of previously collected data from 12 adult persons who stutter who participated in an ABA time-series design while reading orally was undertaken. It was hypothesized that stuttering duration would decrease and there would be a differential reduction in the type of stuttering during FAF, concurrent with previously confirmed reduction of stuttering episodes. A total of 2,971 stuttered syllables were analyzed.

RESULTS

The total stuttering duration (s/min) was significantly reduced by approximately 50% irrespective of stuttering type (p = .0014). Although significant differences in the average duration(s) of the 3 stuttering types (p = .0064) existed, FAF significantly reduced each type of stuttering by approximately 20% (p = .0055). There was no differential effect on the reduction of proportion of stuttering type during FAF (p = .36).

CONCLUSIONS

FAF positively affects the speech of persons who stutter by reducing the proportion of stuttered events with a concomitant decrease in duration of residual stuttering and total stuttering time during oral reading.

The effect of SpeechEasy on stuttering frequency, speech rate, and speech naturalness

The effects of SpeechEasy on stuttering frequency, stuttering severity self-ratings, speech rate, and speech naturalness for 31 adults who stutter were examined. Speech measures were compared for samples obtained with and without the device in place in a dispensing setting. Mean stuttering frequencies were reduced by 79% and 61% for the device compared to the control conditions on reading and monologue tasks, respectively. Mean severity self-ratings decreased by 3.5 points for oral reading and 2.7 for monologue on a 9-point scale. Despite dramatic reductions in stuttering frequency, mean global speech rates in the device condition increased by only 8% in the reading task and 15% for the monologue task, and were well below normal. Further, complete elimination of stuttering was not associated with normalized speech rates. Nevertheless, mean ratings of speech naturalness improved markedly in the device compared to the control condition and, at 3.3 and 3.2 for reading and monologue, respectively, were only slightly outside the normal range. These results show that SpeechEasy produced improved speech outcomes in an assessment setting. However, findings raise the issue of a possible contribution of slowed speech rate to the stuttering reduction effect, especially given participants' instructions to speak chorally with the delayed signal as part of the active listening instructions of the device protocol. Study of device effects in situations of daily living over the long term is necessary to fully explore its treatment potential, especially with respect to long-term stability.

EDUCATIONAL OBJECTIVES

The reader will be able to discuss and evaluate: (1) issues pertinent to evaluating treatment benefits of fluency aids and (2) the effects of SpeechEasy on stuttering frequency, speech rate, and speech naturalness during testing in a dispensing setting for a relatively large sample of adults who stutter.

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).

On the importance of scientific rhetoric in stuttering: a reply to Finn, Bothe, and Bramlett (2005)

PURPOSE

To refute the alleged practice of "pseudoscience" by P. Finn, A. K. Bothe, and R. E. Bramlett (2005) and to illustrate their experimental and systematic bias when evaluating the SpeechEasy, an altered auditory feedback device used in the management of stuttering.

METHOD

We challenged the experimental design that led to the seemingly predetermined outcome of pseudoscience rather than science: Limited preselected literature was submitted to a purposely sampled panel of judges (i.e., their own students). Each criterion deemed pseudoscientific was contested with published peer-reviewed data illustrating the importance of good rhetoric, testability, and logical outcomes from decades of scientific research.

CONCLUSIONS

Stuttering is an involuntary disorder that is highly resistant to therapy. Altered auditory feedback is a derivation of choral speech (nature's most powerful stuttering "inhibitor") that can be synergistically combined with other methods for optimal stuttering inhibition. This approach is logical considering that in stuttering no single treatment is universally helpful. Also, caution is suggested when attempting to differentiate science from pseudoscience in stuttering treatments using the criteria employed by Finn et al. For example, evaluating behavioral therapy outcomes implements a post hoc or untestable system. Speech outcome (i.e., stuttered or fluent speech) determines success or failure of technique use, placing responsibility for failure on those who stutter.

The effect of SpeechEasy on stuttering frequency in laboratory conditions

The effect of SpeechEasy on stuttering frequency during speech produced in a laboratory setting was examined. Thirteen adults who stutter participated. Stuttering frequencies in two baseline conditions were compared to stuttering frequencies with the device fitted according to the manufacturer's protocol. The fitting protocol includes instructions for deliberate use of vowel prolongation. Relative to the initial baseline condition, stuttering was reduced by 74%, 36%, and 49% for reading, monologue, and conversation, respectively. In comparison, stuttering was reduced by 42%, 30%, and 36%, respectively with the device in place, but before participants were instructed to deliberately prolong vowels. Examination of individual response profiles revealed that although stuttering reduced in the device compared to the baseline conditions during at least one of three speech tasks for most participants, degree and pattern of benefit varied greatly across participants.

EDUCATIONAL OBJECTIVES

The reader will be able to: (1) discuss recent research in altered auditory feedback that led to the development of SpeechEasy, (2) analyze and describe issues related to evaluating the treatment benefits of fluency aids, and (3) summarize the range of outcomes that were observed with SpeechEasy in this study.

Altered auditory feedback and the treatment of stuttering: a review

Several authors have suggested that devices delivering altered auditory feedback (AAF) may be a viable treatment for adults and children who stutter. This paper reviews published, peer reviewed journal papers from the past 10 years that investigate the effect of AAF during different speaking conditions, tasks and situations. A review of that literature indicates that considerable experimental evidence and limited Phase 1 treatment outcome evidence has been accumulated about the effect of AAF on the speech of people who stutter. However, critical knowledge about the effect of AAF during conversational speech and in everyday speaking situations is missing. Knowledge about how to determine the correct levels of AAF for individuals, and the characteristics of those likely to benefit from AAF, also needs to be established. At present there is no reason to accept a recent suggestion that AAF devices would be a defensible clinical option for children. In general device development and availability has occurred at a faster pace than clinical trials research.

EDUCATIONAL OBJECTIVES

After reading this paper readers should be able to: (1) describe what altered auditory feedback is and common ways the speech signal is altered in stuttering; (2) describe the effects of AAF on the speech of adults who stutter; (3) provide a critical analysis of the literature in the area of AAF and stuttering.

The effects of temporal modification of second speech signals on stuttering inhibition at two speech rates in adults

The recovery of 'gestural' speech information via the engagement of mirror neurons has been suggested to be the key agent in stuttering inhibition during the presentation of exogenous second speech signals. Based on this hypothesis, we expect the amount of stuttering inhibition to depend on the ease of recovery of exogenous speech gestures. To examine this possibility, linguistically non-congruent second speech signals were temporally compressed and expanded in two experiments. In Experiment 1, 12 participants who stutter read passages aloud at normal and fast speech rates while listening to second speech signals that were 0, 40, 80% compressed, and 40 and 80% expanded. Except for the 80% compressed speech signal, all other stimuli induced significant stuttering inhibition relative to the control condition. The 80% compressed speech signal was the first exogenously presented speech signal that failed to significantly reduce stuttering frequency by 60--70% that has been the case in our research over the years. It was hypothesized that at a compression ratio of 80%, exogenous speech signals generated too many gestures per unit time to allow for adequate gestural recovery via mirror neurons. However, considering that 80% compressed signal was also highly unintelligible, a second experiment was conducted to further examine whether the effects of temporal compression on stuttering inhibition are mediated by speech intelligibility. In Experiment 2, 10 participants who stutter read passages at a normal rate while listening to linguistically non-congruent second speech signals that were compressed by 0, 20, 40, 60, and 80%. Results revealed that 0 and 20% compressed speech signals induced approximately 52% stuttering inhibition. In contrast, compression ratios of 40% and beyond induced only 27% stuttering inhibition although 40 and 60% compressed signals were perceptually intelligible. Our findings suggest that recovery of gestural information is affected by temporal compression before intelligibility starts to decrease.

Science and pseudoscience in communication disorders: criteria and applications

PURPOSE

The purpose of this tutorial is to describe 10 criteria that may help clinicians distinguish between scientific and pseudoscientific treatment claims. The criteria are illustrated, first for considering whether to use a newly developed treatment and second for attempting to understand arguments about controversial treatments.

METHOD

Pseudoscience refers to claims that appear to be based on the scientific method but are not. Ten criteria for distinguishing between scientific and pseudoscientific treatment claims are described. These criteria are illustrated by using them to assess a current treatment for stuttering, the SpeechEasy device. The authors read the available literature about the device and developed a consensus set of decisions about the 10 criteria. To minimize any bias, a second set of independent judges evaluated a sample of the same literature. The criteria are also illustrated by using them to assess controversies surrounding 2 treatment approaches: Fast ForWord and facilitated communication.

CONCLUSIONS

Clinicians are increasingly being held responsible for the evidence base that supports their practice. The power of these 10 criteria lies in their ability to help clinicians focus their attention on the credibility of that base and to guide their decisions for recommending or using a treatment.

The Perception of Speech Naturalness of Post-Therapeutic and Altered Auditory Feedback Speech of Adults with Mild and Severe Stuttering

The effect of therapy and altered auditory feedback (AAF) on the perception of speech naturalness of people who stutter was examined. Thirty-five naive young adult listeners rated speech samples from fluent speakers and individuals who stutter. Samples came from normal adults who spoke Standard American English; adults with mild or severe stuttering who spoke under conditions of non-altered feedback (NAF), delayed auditory feedback (DAF), and frequency-altered feedback (FAF); and adults with mild or severe stuttering prior to and following successful completion of a Precision Fluency Shaping Program. Speech produced under AAF was rated as significantly more natural sounding than speech from the same individuals under NAF (p < 0.0001). Speech produced during FAF was judged to be more natural sounding than that produced during DAF for those with mild (p = 0.003) and severe (p < 0.0001) stuttering. Mild stuttered speech was judged to have more natural-sounding speech than severe stuttered speech during AAF (p < 0.0001). Speech from individuals following therapy was rated significantly less natural sounding than that from individuals during AAF for both mild and severe stuttering (p < 0.0001). The speech of individuals prior to therapy was rated significantly more natural than their speech produced after therapy (p < 0.0001). Speech from normal fluent speakers was rated as significantly more natural sounding than all samples produced from the individuals who stutter (p < 0.0001). These findings support the contention that AAF benefits those who stutter through a reduction of stuttering with a gain in perceived speech naturalness.

Self-reported efficacy of an ear-level prosthetic device that delivers altered auditory feedback for the management of stuttering

Numerous past efficacy studies in stuttering treatment have typically failed to assess generalization of therapeutic gains across speaking environments over time. The purpose of this study was to use a self-report format to gain insight into the improvements of clients who purchased an all in-the-ear device that provides altered auditory feedback to manage stuttering symptoms across everyday speaking situations. A total of 105 participants (age 7-81 years) returned completed questionnaires that examined seven parameters of stuttering behavior before acquiring the prosthetic device and after using the device with minimal clinical intervention for an average of 6 months. Across each parameter, participants rated a significant (P<0.001) improvement of approximately two units on seven-point scales after beginning to use the prosthetic device. In addition, the device received high overall satisfaction ratings, with a median score of 2.0 on the seven-point scale. Self-report is a 'must' for examining clinical efficacy in a disorder such as stuttering, which is so amenable to 'clinic room fluency' yet highly resistant to long-term amelioration. The data suggest that this device is helping to provide its users with functional, effective and efficient management of stuttering without the need for extended clinical follow-up.

Orofacial movements associated with fluent speech in persons who stutter

This study was intended to replicate and extend previous findings that (a) during fluent speech persons who stutter (PS) and those who do not (NS) differ in their vocal tract closing movements (L. Max, A. J. Caruso, and V. L. Gracco, 2003) and (b) ratios relating lip and tongue speed to jaw speed increase with stuttering severity (M. D. McClean and C. R. Runyan, 2000). An electromagnetic system was used to record movements of the upper lip, lower lip, tongue, and jaw of 43 NS and 37 PS during productions of a nonsense phrase and a sentence. Measurement and analysis of movement speeds, durations, and ratios of lip and tongue speed to jaw speed were performed on fluent productions of a nonsense phrase and sentence. Statistical comparisons were made between PS with low and high stuttering severity levels (LPS and HPS) and NS. Significant variations across groups in movement speed and duration were observed, but the pattern of these effects was complex and did not replicate the results of the two earlier studies. In the nonsense phrase, significant reductions in lower lip closing duration, jaw closing duration, and jaw closing speed were seen in PS. In the sentence task, HPS showed elevated tongue opening and closing durations. For tongue opening in the sentence, LPS showed elevated speeds and HPS showed reduced speeds. The elevated speeds for LPS are interpreted as a contributing factor to speech disfluency, whereas the reduced speeds and increased durations in HPS are attributed to adaptive behavior intended to facilitate fluent speech. Significant group effects were not seen for the speed ratio measures. Results are discussed in relation to multivariate analyses intended to identify subgroups of PS.

Stuttering: a dynamic motor control disorder

The purpose of this review is to determine what neural mechanisms may be dysfunctional in stuttering. Three sources of evidence are reviewed. First, studies of dynamic inter-relationships among brain regions during normal speech and in persons who stutter (PWS) suggest that the timing of neural activity in different regions may be abnormal in PWS. Second, the brain lesions associated with acquired stuttering are reviewed. These indicate that in a high percentage of cases, the primary speech and language regions are not affected but lesions involve other structures, such as the basal ganglia, which may modulate the primary speech and language regions. Third, to characterize the motor control disorder in stuttering, similarities and differences from focal dystonias such as spasmodic dysphonia (SD) and Tourette's syndrome (TS) are reviewed. This review indicates that the central control abnormalities in stuttering are not due to disturbance in one particular brain region but rather a system dysfunction that interferes with rapid and dynamic speech processing for production.

EDUCATIONAL OBJECTIVES

The reader will be able to describe: (1) the similarities and differences between stuttering and other speech motor control disorders, (2) which brain lesions are most likely to produce acquired stuttering in adults, and (3) what type of brain abnormality most likely underlies stuttering.

Parkinsonian speech disfluencies: effects of L-dopa-related fluctuations

The excess dopamine theory of stuttering (Wu et al., 1997) contends that stuttering may be related to excess levels of the neurotransmitter dopamine in the brain. As Parkinson's disease (PD) patients commonly exhibit changes in dopamine levels accompanied by changes in motor performance, the present study examined disfluency in PD patients to gain information on the role of dopamine in speech disfluencies. Nine PD patients with no history of developmental stuttering were recorded once before and twice after taking their morning medication (on separate days). They read a passage and produced a monologue. Within-word and overall speech disfluencies were calculated at each recording. Through motor testing, it was inferred that participants had relatively low dopamine levels before taking medication, and relatively high dopamine levels after taking medication. There were no group changes in disfluency levels when the low-dopamine and high-dopamine states were compared. There were, however, significant differences in percent disfluencies between the PD participants and age-matched controls. The results of this study do not strongly support the excess dopamine theory of stuttering. Rather, the disfluency changes exhibited by individual participants support a hypothesis that speech disfluencies may be related to increases or decreases in dopamine levels in the brain.

EDUCATIONAL OBJECTIVES

The reader will learn about: (1). the characteristics of disfluent speech exhibited by speakers with Parkinson's disease. (2). The effect of L-dopa based medications on disfluencies of Parkinsonian speakers. (3). The complex role brain dopamine levels may play in disfluent speaking behavior.

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.