Tim Saltuklaroglu | University of Tennessee Knoxville (original) (raw)

Papers by Tim Saltuklaroglu

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Neuropsychologia, 2009

Motor involvement in speech perception has been recently studied using a variety of techniques. I... more Motor involvement in speech perception has been recently studied using a variety of techniques. In the current study, EEG measurements from Cz, C3 and C4 electrodes were used to examine the relative power of the mu rhythm (i.e., 8-13 Hz) in response to various audio-visual speech and non-speech stimuli, as suppression of these rhythms is considered an index of 'mirror neuron' (i.e., motor) activity. Fourteen adult native English speaking females watched and listened to nine audio-video stimuli clips assembled from three different auditory stimuli (speech, noise, and pure tone) combined with three different video stimuli (speech, noise, and kaleidoscope-made from scrambling an image from the visual speech). Relative to the noise-noise (baseline condition), all visual speech conditions resulted in significant levels of suppression, a finding that is consistent with previous reports of mirror activity to visual speech and mu suppression to 'biological' stimuli. None of the non-speech conditions or conditions in which speech was presented via audition only resulted in any significant suppression of the mu rhythm in this population. Thus, visual speech perception appears to be more closely associated with motor activity than acoustic speech perception. It is postulated that in this study, the processing demands incurred by the task were insufficient for inducing significant mu suppression via acoustic speech only. The findings are discussed in theoretical contexts of speech perception and the mirror system. We suggest that this technique may offer a cost-efficient, non-invasive technique for measuring motor activity during speech perception.

Neuroscience Letters, 2006

Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) ha... more Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) have repeatedly been found to be highly effective inhibitors of stuttering. Sine wave analogs of speech consist of a trio of changing pure tones representative of formant frequencies. They are otherwise devoid of traditional speech cues, yet have proven to evoke consistent linguistic percepts in listeners. Thus, we investigated the potency of sinusoidal speech for inhibiting stuttering. Ten adults who stutter read while listening to (a) forward-flowing natural speech; (b) forward-flowing sinusoid analogs of natural speech; (c) reversed natural speech; (d) reversed sinusoid analogs of natural speech; and (e) a continuous 1000 Hz pure tone. The levels of stuttering inhibition achieved using the sinusoidal stimuli were potent and not significantly different from those achieved using natural speech (∼50% in forward conditions and ∼25% in the reversed conditions), suggesting that the patterns of undulating pure tones are sufficient to endow sinusoidal sentences with 'quasi-gestural' qualities. These data highlight the sensitivity of a specialized 'phonetic module' for extracting gestural information from sensory stimuli. Stuttering inhibition is thought to occur when perceived gestural information facilitates fluent productions via the engagement of mirror neurons (e.g., in Broca's area), which appear to play a crucial role in our ability to perceive and produce speech.

Neuroscience Letters, 2001

This study investigated the effects of producing and listening to the vowel /a/ on the frequency ... more This study investigated the effects of producing and listening to the vowel /a/ on the frequency of overt stuttering moments in eight people who stuttered. Stuttering frequency counts were made for the speech produced in the control condition, and after each of these four experimental conditions: (a) producing a vowel /a/ for 4 s; (b) producing a vowel /a/ for 4 s and waiting for 4 s; (c) listening to a recording of the vowel /a/ for 4 s; and (d) listening to a recording of the vowel / a/ for 4 s and waiting for 4 s. A signi®cant reduction in the stuttering frequency was only observed following production of the vowel /a/ without a 4 s delay (P 0:02), suggesting that the vowel production prior to speech, serves as a temporary¯uency enhancer. Its similarity to the occurrence of overt stuttering moments (e.g. discrete part-word repetitions and prolongation's) and its relationship to the fundamental nature of the pathology are discussed. q

Medical Hypotheses, 2002

Treatment for stuttering attempts to reduce or eliminate the observable core markers of the disor... more Treatment for stuttering attempts to reduce or eliminate the observable core markers of the disorder, specifically repetitions and prolongation. In this hypothesis, it is proposed that stuttering may be inhibited by two distinct yet related procedures: active inhibition and passive inhibition. Active inhibition is brought about when the person who stutters makes volitional changes to his or her speaking pattern, such as when employing behavioral modification techniques. Passive inhibition automatically inhibits the involuntary stuttering block and can be induced from an external source, such as altered auditory feedback, or by the use of sufficient active inhibition. It is suggested that passively inhibiting stuttering results in speech that is more automatic, natural sounding, and truly fluent speech than the speech that is derived primarily from active inhibition. Evidence of passive inhibition resulting from active inhibition can be seen when people who stutter exhibit uncontrolled fluency following behavioral therapy.

International Journal of Psychophysiology, 2006

The present study examined the psychophysiological responses of fluent listeners to stuttered spe... more The present study examined the psychophysiological responses of fluent listeners to stuttered speech. Specifically, skin conductance and heart rate changes were measured from adults who do not stutter while watching one-minute video speech samples of persons stutter read aloud. Fifteen adult participants observed three stuttered and three fluent speech samples, presented in random order with a two-minute interstimulus intervals. Results revealed that observing stuttered speech evoked a significant increase in skin conductance and a significant deceleration in heart rate relative to watching fluent speech samples. These findings suggest that listeners are physiologically aroused by stuttering and appear to maintain feelings of unpleasantness to stuttered speech. Further, deceleration in heart rate during stuttered samples also suggest that listeners may be paying more attention to the stuttered speech samples as compared to the fluent speech samples. We speculate that aberrant and anomalous stuttering behaviors probably simulate the mirror neuronal mechanism eliciting the emotional arousal associated within them. Such physiological arousal may provide the emotional genesis to the listener's negative stereotypical perceptions towards people who stutter. D

International Journal of Language & Communication Disorders, 2002

... Joseph Kalinowski, Vikram N. Dayalu and Tim Saltuklaroglu Department of Communication, Scienc... more ... Joseph Kalinowski, Vikram N. Dayalu and Tim Saltuklaroglu Department of Communication, Sciences and Disorders, School of Allied Health, Belk Building, Oglesby Drive, Greenville, NC 27858, USA; e-mail: kalinowskij@mail.ecu.edu ... Behavior Modi cation, 25, 116–139. ...

International Journal of Language & Communication Disorders, 2009

Background: Stuttering is prone to strike during speech initiation more so than at any other poin... more Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate speech before it can go into effect and, therefore, it might not be as helpful as true choral speech during speech initiation. Aims: To examine how AAF and choral speech differentially enhance fluency during speech initiation and in subsequent portions of utterances. Methods & Procedures: Ten participants who stuttered read passages without altered feedback (NAF), under four AAF conditions and under a true choral speech condition. Each condition was blocked into ten 10 s trials separated by 5 s intervals so each trial required 'cold' speech initiation. In the first analysis, comparisons of stuttering frequencies were made across conditions. A second, finer grain analysis involved examining stuttering frequencies on the initial syllable, the subsequent four syllables produced and the five syllables produced immediately after the midpoint of each trial. Outcomes & Results: On average, AAF reduced stuttering by approximately 68% relative to the NAF condition. Stuttering frequencies on the initial syllables were considerably higher than on the other syllables analysed (0.45 and 0.34 for NAF and AAF conditions, respectively). AAF conditions than in the NAF condition (approximately 66%) with frequencies on the last nine syllables analysed averaging 0.15 and 0.05 for NAF and AAF conditions, respectively. In the true choral speech condition, stuttering was virtually (approximately 98%) eliminated across all utterances and all syllable positions. Conclusions & Implications: Altered auditory feedback effectively inhibits stuttering immediately after speech has been initiated. However, unlike a true choral signal, which is exogenously initiated and offers the most complete fluency enhancement, AAF requires speech to be initiated by the user and 'fed back' before it can directly inhibit stuttering. It is suggested that AAF can be a viable clinical option for those who stutter and should often be used in combination with therapeutic techniques, particularly those that aid speech initiation. The substantially higher rate of stuttering occurring on initiation supports a hypothesis that overt stuttering events help 'release' and 'inhibit' central stuttering blocks. This perspective is examined in the context of internal models and mirror neurons.

International Journal of Language & Communication Disorders, 2009

Background: Stuttering is prone to strike during speech initiation more so than at any other poin... more Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate speech before it can go into effect and, therefore, it might not be as helpful as true choral speech during speech initiation. Aims: To examine how AAF and choral speech differentially enhance fluency during speech initiation and in subsequent portions of utterances. Methods & Procedures: Ten participants who stuttered read passages without altered feedback (NAF), under four AAF conditions and under a true choral speech condition. Each condition was blocked into ten 10 s trials separated by 5 s intervals so each trial required 'cold' speech initiation. In the first analysis, comparisons of stuttering frequencies were made across conditions. A second, finer grain analysis involved examining stuttering frequencies on the initial syllable, the subsequent four syllables produced and the five syllables produced immediately after the midpoint of each trial. Outcomes & Results: On average, AAF reduced stuttering by approximately 68% relative to the NAF condition. Stuttering frequencies on the initial syllables were considerably higher than on the other syllables analysed (0.45 and 0.34 for NAF and AAF conditions, respectively). AAF conditions than in the NAF condition (approximately 66%) with frequencies on the last nine syllables analysed averaging 0.15 and 0.05 for NAF and AAF conditions, respectively. In the true choral speech condition, stuttering was virtually (approximately 98%) eliminated across all utterances and all syllable positions. Conclusions & Implications: Altered auditory feedback effectively inhibits stuttering immediately after speech has been initiated. However, unlike a true choral signal, which is exogenously initiated and offers the most complete fluency enhancement, AAF requires speech to be initiated by the user and 'fed back' before it can directly inhibit stuttering. It is suggested that AAF can be a viable clinical option for those who stutter and should often be used in combination with therapeutic techniques, particularly those that aid speech initiation. The substantially higher rate of stuttering occurring on initiation supports a hypothesis that overt stuttering events help 'release' and 'inhibit' central stuttering blocks. This perspective is examined in the context of internal models and mirror neurons.

Journal of Speech Language and Hearing Research, 2010

To challenge the findings of Pollard, Ellis, Finan, and Ramig (2009), who examined 11 participant... more To challenge the findings of Pollard, Ellis, Finan, and Ramig (2009), who examined 11 participants using the SpeechEasy, an in-the-ear device that employs altered auditory feedback to reduce stuttering, in a 6-month "clinical trial." Pollard et al. failed to demonstrate a significant treatment effect on stuttering frequency, yet found positive subjective self-report data across four months of use. The authors concluded that the device was not therapeutically useful and further testing is unwarranted. We dispute Pollard et al. on the following grounds: Their operational definition of stuttering is confounded as it does not adequately distinguish true stuttering from "normally" disfluent speech or from volitionally produced initiating gestures taught to be used as part of the treatment protocol, nor is it the definition used in their pre- and posttreatment stuttering assessment instrument; they failed to maintain participant adherence to the treatment protocol of device usage; they utilized an inadequate question-asking task; and their conclusion of no significant treatment effect that is drawn from their inferential statistical analyses of group data. In light of problematic objective measurements, reported positive subjective findings, a robust corpus of contradictory data, and the need for alternative stuttering treatments, we argue that the SpeechEasy merits further investigation.

International Journal of Language & Communication Disorders, 2006

Bloodstein reviewed hundreds of studies that investigated the efficacy of therapeutic protocols f... more Bloodstein reviewed hundreds of studies that investigated the efficacy of therapeutic protocols for ameliorating the stuttering syndrome. Surprisingly, almost all were effective in significantly reducing overtly perceptible behaviours such as repetitions and prolongations of speech sounds. These results seem highly improbable considering that many of the treatment methods were diametrically opposed in their principles and implementation procedures (e.g. psychoanalysis, drug therapy, behaviourism, cognitive behavioural therapy and auditory feedback devices with rate control, etc.). In addition, time and more ecologically valid methods such as self-report measures demonstrate that overt measures of success are tenuous, their ameliorative effects tend to diminish drastically over time and show poor generalizability. Further, the real conundrum in stuttering therapy is the failure to acknowledge stuttering as a complete syndrome of continuous compensatory behaviours. To highlight how self-report measures serve as a primary tool to understand the syndrome-like nature of stuttering and to test the efficacy of the therapy outside the confines of the clinic and the needs of the people who stutter. In the past, therapeutic efficacy has typically been measured by the reduction in overtly observable and countable events of stuttering such as repetitions and prolongations. However, recent neuroimaging data and our research suggest that the stuttering syndrome is more than the mere presence of peripheral speech disruptions. Stuttering is a central, experiential sense of 'loss of control' that manifests itself across a continuum of compensatory behaviours from the central nervous system outwards to the speech periphery. In other words, aberrant neural activity, as well as covert stuttering behaviours, subperceptual stuttering forms and overt speech disruptions are all effects or compensations for the central involuntary 'neural block'. Hence, by counting only perceptible portions of the disorder, efficacy measures 'fail to capture' the experiential sense of 'loss of control' and the covert compensatory behaviours of the disorder (i.e. avoidances of words or situations, substitutions, circumlocutions, subperceptual stuttering forms, etc.). Furthermore, unnatural sounding speech, decreased ease of speech production, elevated levels of clinic room fluency and poor reliability in counting stuttering behaviours confound the overt measures in the clinic milieu. Therefore, while overt measures remain important, used in isolation, they cannot provide a 'true metric' of efficacy. Any efficient and effective means of evaluating intervention methods over the long-term should include a form of self-report as a primary tool as it best accesses the experiential sense of 'loss of control' and other covert behaviours. Overt measures should be used to supplement or complement the self-report data.

Neuroscience Letters, 2003

We explored a possible temporal window for central stuttering inhibition via exogenously presente... more We explored a possible temporal window for central stuttering inhibition via exogenously presented speech signals. Thirteen adults who stutter were asked to read while listening to a continuous vowel /a/, or a repeating 1 s vowel /a/ followed by 1, 3 and 5 s silences. In all conditions, stuttering was significantly reduced. However, the continuous and 1 s repeating conditions showed the greatest reduction in stuttering relative to all other conditions. Furthermore, these conditions did not differ significantly from each other, suggesting a temporal window of at least 1 s for stuttering inhibition induced by a 1 s stimulus. We propose that exogenous speech signals provide an additional speech source that engages mirror neurons for 'on-line' stuttering inhibition during continous speech. Employing dual speech sources results in 'on-line' stuttering inhibition and continuous speech flow. In contrast, endogenous (single source) inhibitory techniques require speech flow to be interrupted and go 'off-line' to derive the mirror neuronal inhibition. q

International Journal of Language & Communication Disorders, 2004

Background: Self-contained ear-level devices delivering altered auditory feedback (AAF) for the a... more Background: Self-contained ear-level devices delivering altered auditory feedback (AAF) for the application with those who stutter were only recently developed .

Folia Phoniatrica Et Logopaedica, 2009

This study assessed the impact of stuttering via a questionnaire in which fluent individuals were... more This study assessed the impact of stuttering via a questionnaire in which fluent individuals were asked to assume the mindset of persons who stutter (PWS) in various life aspects, including vocation, romance, daily activities, friends/social life, family and general lifestyle. The perceived impact of stuttering through the mind's eyes of nonstutterers is supposed to reflect respondents' abilities to impart 'theory of mind' in addressing social penalties related to stuttering. Ninety-one university students answered a questionnaire containing 56 statements on a 7-point Likert scale. Forty-four participants (mean age = 20.4, SD = 4.4) were randomly selected to assume a stuttering identity and 47 respondents (mean age = 20.5, SD = 3.1) to assume their normally fluent identity. Significant differences between groups were found in more than two thirds of items regarding employment, romance, and daily activities, and in fewer than half of items regarding family, friend/social life, and general life style (p <0.001). The social penalties associated with stuttering appear to be apparent to fluent individuals, especially in areas of vocation, romance, and daily activities, suggesting that nonstuttering individuals, when assuming the role of PWS, are capable of at least temporarily feeling the negative impact of stuttering.

International Journal of Language & Communication Disorders, 2009

Background: Previous studies have found simultaneous increases in skin conductance response and d... more Background: Previous studies have found simultaneous increases in skin conductance response and decreases in heart rate when normally fluent speakers watched and listened to stuttered speech compared with fluent speech, suggesting that stuttering induces arousal and emotional unpleasantness in listeners. However, physiological responses of persons who stutter observing stuttering and fluent speech has not been measured. Research suggests that the mechanism responsible for listeners' reactions is the mirror neuron system. The mirror neuron system activates when perceiving and producing goal-directed actions and forms the link between action perception and action production. Aims: To compare physiological responses elicited via fluent and stuttered speech in fluent and persons who stutter groups.

International Journal of Neuroscience, 2004

Stuttering can be effectively inhibited via exogenous sensory signals (e.g., speaking in unison o... more Stuttering can be effectively inhibited via exogenous sensory signals (e.g., speaking in unison or using altered auditory feedback) or by using endogenous motoric strategies (e.g., singing or therapeutically implementing long vowel prolongations to reduce speech rates). We propose that these channels, which superficially appear to be diametrically opposite, centrally converge in the engagement of mirror neurons for fluent gestural productions. Sensory changes incurred via exogenous speech signals allow for direct engagement of mirror systems, while endogenous motor strategies appear to require significant departures from normal speech production (e.g., highly unnatural or droned speech) to engage mirror systems. Thus, paradoxically, stuttering is prone to resurface during attempts to impose naturalness upon therapeutic speech.

Journal of Clinical and Experimental Neuropsychology, 2004

This study examined fluency enhancement in people who stutter via the concomitant presentation of... more This study examined fluency enhancement in people who stutter via the concomitant presentation of silently mouthed visual speech. Ten adults who stutter recited memorized text while watching another speaker silently mouth linguistically equivalent and linguistically different material. Relative to a control condition, in which no concomitant stimulus was provided, stuttering was reduced by 71% in the linguistically equivalent condition versus only 35% in the linguistically different condition. Despite being an 'incomplete' second speech signal, visual speech possesses the capacity to immediately and substantially enhance fluency when it is linguistically equivalent to the intended utterance. It is suggested that fluency enhancement via concomitantly presented external speech is achieved through the extraction of relevant speech gestures from the external speech signal that compliment the intended production, thereby compensating for possible internal inconsistencies in the matching of speech codes in people who stutter. As visual speech perception relies on fewer redundant cues to demarcate the intended gestures, when used as an external stuttering inhibitor, higher degrees of linguistic equivalence seem to be necessary for optimal stuttering inhibition.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Human Movement Science, 2009

We examined the disruptive effects of stuttering on manual performance during simultaneous speaki... more We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.

Neuropsychologia, 2009

Motor involvement in speech perception has been recently studied using a variety of techniques. I... more Motor involvement in speech perception has been recently studied using a variety of techniques. In the current study, EEG measurements from Cz, C3 and C4 electrodes were used to examine the relative power of the mu rhythm (i.e., 8-13 Hz) in response to various audio-visual speech and non-speech stimuli, as suppression of these rhythms is considered an index of 'mirror neuron' (i.e., motor) activity. Fourteen adult native English speaking females watched and listened to nine audio-video stimuli clips assembled from three different auditory stimuli (speech, noise, and pure tone) combined with three different video stimuli (speech, noise, and kaleidoscope-made from scrambling an image from the visual speech). Relative to the noise-noise (baseline condition), all visual speech conditions resulted in significant levels of suppression, a finding that is consistent with previous reports of mirror activity to visual speech and mu suppression to 'biological' stimuli. None of the non-speech conditions or conditions in which speech was presented via audition only resulted in any significant suppression of the mu rhythm in this population. Thus, visual speech perception appears to be more closely associated with motor activity than acoustic speech perception. It is postulated that in this study, the processing demands incurred by the task were insufficient for inducing significant mu suppression via acoustic speech only. The findings are discussed in theoretical contexts of speech perception and the mirror system. We suggest that this technique may offer a cost-efficient, non-invasive technique for measuring motor activity during speech perception.

Neuroscience Letters, 2006

Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) ha... more Sensory signals containing speech or gestural (articulatory) information (e.g., choral speech) have repeatedly been found to be highly effective inhibitors of stuttering. Sine wave analogs of speech consist of a trio of changing pure tones representative of formant frequencies. They are otherwise devoid of traditional speech cues, yet have proven to evoke consistent linguistic percepts in listeners. Thus, we investigated the potency of sinusoidal speech for inhibiting stuttering. Ten adults who stutter read while listening to (a) forward-flowing natural speech; (b) forward-flowing sinusoid analogs of natural speech; (c) reversed natural speech; (d) reversed sinusoid analogs of natural speech; and (e) a continuous 1000 Hz pure tone. The levels of stuttering inhibition achieved using the sinusoidal stimuli were potent and not significantly different from those achieved using natural speech (∼50% in forward conditions and ∼25% in the reversed conditions), suggesting that the patterns of undulating pure tones are sufficient to endow sinusoidal sentences with 'quasi-gestural' qualities. These data highlight the sensitivity of a specialized 'phonetic module' for extracting gestural information from sensory stimuli. Stuttering inhibition is thought to occur when perceived gestural information facilitates fluent productions via the engagement of mirror neurons (e.g., in Broca's area), which appear to play a crucial role in our ability to perceive and produce speech.

Neuroscience Letters, 2001

This study investigated the effects of producing and listening to the vowel /a/ on the frequency ... more This study investigated the effects of producing and listening to the vowel /a/ on the frequency of overt stuttering moments in eight people who stuttered. Stuttering frequency counts were made for the speech produced in the control condition, and after each of these four experimental conditions: (a) producing a vowel /a/ for 4 s; (b) producing a vowel /a/ for 4 s and waiting for 4 s; (c) listening to a recording of the vowel /a/ for 4 s; and (d) listening to a recording of the vowel / a/ for 4 s and waiting for 4 s. A signi®cant reduction in the stuttering frequency was only observed following production of the vowel /a/ without a 4 s delay (P 0:02), suggesting that the vowel production prior to speech, serves as a temporary¯uency enhancer. Its similarity to the occurrence of overt stuttering moments (e.g. discrete part-word repetitions and prolongation's) and its relationship to the fundamental nature of the pathology are discussed. q

Medical Hypotheses, 2002

Treatment for stuttering attempts to reduce or eliminate the observable core markers of the disor... more Treatment for stuttering attempts to reduce or eliminate the observable core markers of the disorder, specifically repetitions and prolongation. In this hypothesis, it is proposed that stuttering may be inhibited by two distinct yet related procedures: active inhibition and passive inhibition. Active inhibition is brought about when the person who stutters makes volitional changes to his or her speaking pattern, such as when employing behavioral modification techniques. Passive inhibition automatically inhibits the involuntary stuttering block and can be induced from an external source, such as altered auditory feedback, or by the use of sufficient active inhibition. It is suggested that passively inhibiting stuttering results in speech that is more automatic, natural sounding, and truly fluent speech than the speech that is derived primarily from active inhibition. Evidence of passive inhibition resulting from active inhibition can be seen when people who stutter exhibit uncontrolled fluency following behavioral therapy.

International Journal of Psychophysiology, 2006

The present study examined the psychophysiological responses of fluent listeners to stuttered spe... more The present study examined the psychophysiological responses of fluent listeners to stuttered speech. Specifically, skin conductance and heart rate changes were measured from adults who do not stutter while watching one-minute video speech samples of persons stutter read aloud. Fifteen adult participants observed three stuttered and three fluent speech samples, presented in random order with a two-minute interstimulus intervals. Results revealed that observing stuttered speech evoked a significant increase in skin conductance and a significant deceleration in heart rate relative to watching fluent speech samples. These findings suggest that listeners are physiologically aroused by stuttering and appear to maintain feelings of unpleasantness to stuttered speech. Further, deceleration in heart rate during stuttered samples also suggest that listeners may be paying more attention to the stuttered speech samples as compared to the fluent speech samples. We speculate that aberrant and anomalous stuttering behaviors probably simulate the mirror neuronal mechanism eliciting the emotional arousal associated within them. Such physiological arousal may provide the emotional genesis to the listener's negative stereotypical perceptions towards people who stutter. D

International Journal of Language & Communication Disorders, 2002

... Joseph Kalinowski, Vikram N. Dayalu and Tim Saltuklaroglu Department of Communication, Scienc... more ... Joseph Kalinowski, Vikram N. Dayalu and Tim Saltuklaroglu Department of Communication, Sciences and Disorders, School of Allied Health, Belk Building, Oglesby Drive, Greenville, NC 27858, USA; e-mail: kalinowskij@mail.ecu.edu ... Behavior Modi cation, 25, 116–139. ...

International Journal of Language & Communication Disorders, 2009

Background: Stuttering is prone to strike during speech initiation more so than at any other poin... more Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate speech before it can go into effect and, therefore, it might not be as helpful as true choral speech during speech initiation. Aims: To examine how AAF and choral speech differentially enhance fluency during speech initiation and in subsequent portions of utterances. Methods & Procedures: Ten participants who stuttered read passages without altered feedback (NAF), under four AAF conditions and under a true choral speech condition. Each condition was blocked into ten 10 s trials separated by 5 s intervals so each trial required 'cold' speech initiation. In the first analysis, comparisons of stuttering frequencies were made across conditions. A second, finer grain analysis involved examining stuttering frequencies on the initial syllable, the subsequent four syllables produced and the five syllables produced immediately after the midpoint of each trial. Outcomes & Results: On average, AAF reduced stuttering by approximately 68% relative to the NAF condition. Stuttering frequencies on the initial syllables were considerably higher than on the other syllables analysed (0.45 and 0.34 for NAF and AAF conditions, respectively). AAF conditions than in the NAF condition (approximately 66%) with frequencies on the last nine syllables analysed averaging 0.15 and 0.05 for NAF and AAF conditions, respectively. In the true choral speech condition, stuttering was virtually (approximately 98%) eliminated across all utterances and all syllable positions. Conclusions & Implications: Altered auditory feedback effectively inhibits stuttering immediately after speech has been initiated. However, unlike a true choral signal, which is exogenously initiated and offers the most complete fluency enhancement, AAF requires speech to be initiated by the user and 'fed back' before it can directly inhibit stuttering. It is suggested that AAF can be a viable clinical option for those who stutter and should often be used in combination with therapeutic techniques, particularly those that aid speech initiation. The substantially higher rate of stuttering occurring on initiation supports a hypothesis that overt stuttering events help 'release' and 'inhibit' central stuttering blocks. This perspective is examined in the context of internal models and mirror neurons.

International Journal of Language & Communication Disorders, 2009

Background: Stuttering is prone to strike during speech initiation more so than at any other poin... more Background: Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate speech before it can go into effect and, therefore, it might not be as helpful as true choral speech during speech initiation. Aims: To examine how AAF and choral speech differentially enhance fluency during speech initiation and in subsequent portions of utterances. Methods & Procedures: Ten participants who stuttered read passages without altered feedback (NAF), under four AAF conditions and under a true choral speech condition. Each condition was blocked into ten 10 s trials separated by 5 s intervals so each trial required 'cold' speech initiation. In the first analysis, comparisons of stuttering frequencies were made across conditions. A second, finer grain analysis involved examining stuttering frequencies on the initial syllable, the subsequent four syllables produced and the five syllables produced immediately after the midpoint of each trial. Outcomes & Results: On average, AAF reduced stuttering by approximately 68% relative to the NAF condition. Stuttering frequencies on the initial syllables were considerably higher than on the other syllables analysed (0.45 and 0.34 for NAF and AAF conditions, respectively). AAF conditions than in the NAF condition (approximately 66%) with frequencies on the last nine syllables analysed averaging 0.15 and 0.05 for NAF and AAF conditions, respectively. In the true choral speech condition, stuttering was virtually (approximately 98%) eliminated across all utterances and all syllable positions. Conclusions & Implications: Altered auditory feedback effectively inhibits stuttering immediately after speech has been initiated. However, unlike a true choral signal, which is exogenously initiated and offers the most complete fluency enhancement, AAF requires speech to be initiated by the user and 'fed back' before it can directly inhibit stuttering. It is suggested that AAF can be a viable clinical option for those who stutter and should often be used in combination with therapeutic techniques, particularly those that aid speech initiation. The substantially higher rate of stuttering occurring on initiation supports a hypothesis that overt stuttering events help 'release' and 'inhibit' central stuttering blocks. This perspective is examined in the context of internal models and mirror neurons.

Journal of Speech Language and Hearing Research, 2010

To challenge the findings of Pollard, Ellis, Finan, and Ramig (2009), who examined 11 participant... more To challenge the findings of Pollard, Ellis, Finan, and Ramig (2009), who examined 11 participants using the SpeechEasy, an in-the-ear device that employs altered auditory feedback to reduce stuttering, in a 6-month "clinical trial." Pollard et al. failed to demonstrate a significant treatment effect on stuttering frequency, yet found positive subjective self-report data across four months of use. The authors concluded that the device was not therapeutically useful and further testing is unwarranted. We dispute Pollard et al. on the following grounds: Their operational definition of stuttering is confounded as it does not adequately distinguish true stuttering from "normally" disfluent speech or from volitionally produced initiating gestures taught to be used as part of the treatment protocol, nor is it the definition used in their pre- and posttreatment stuttering assessment instrument; they failed to maintain participant adherence to the treatment protocol of device usage; they utilized an inadequate question-asking task; and their conclusion of no significant treatment effect that is drawn from their inferential statistical analyses of group data. In light of problematic objective measurements, reported positive subjective findings, a robust corpus of contradictory data, and the need for alternative stuttering treatments, we argue that the SpeechEasy merits further investigation.

International Journal of Language & Communication Disorders, 2006

Bloodstein reviewed hundreds of studies that investigated the efficacy of therapeutic protocols f... more Bloodstein reviewed hundreds of studies that investigated the efficacy of therapeutic protocols for ameliorating the stuttering syndrome. Surprisingly, almost all were effective in significantly reducing overtly perceptible behaviours such as repetitions and prolongations of speech sounds. These results seem highly improbable considering that many of the treatment methods were diametrically opposed in their principles and implementation procedures (e.g. psychoanalysis, drug therapy, behaviourism, cognitive behavioural therapy and auditory feedback devices with rate control, etc.). In addition, time and more ecologically valid methods such as self-report measures demonstrate that overt measures of success are tenuous, their ameliorative effects tend to diminish drastically over time and show poor generalizability. Further, the real conundrum in stuttering therapy is the failure to acknowledge stuttering as a complete syndrome of continuous compensatory behaviours. To highlight how self-report measures serve as a primary tool to understand the syndrome-like nature of stuttering and to test the efficacy of the therapy outside the confines of the clinic and the needs of the people who stutter. In the past, therapeutic efficacy has typically been measured by the reduction in overtly observable and countable events of stuttering such as repetitions and prolongations. However, recent neuroimaging data and our research suggest that the stuttering syndrome is more than the mere presence of peripheral speech disruptions. Stuttering is a central, experiential sense of 'loss of control' that manifests itself across a continuum of compensatory behaviours from the central nervous system outwards to the speech periphery. In other words, aberrant neural activity, as well as covert stuttering behaviours, subperceptual stuttering forms and overt speech disruptions are all effects or compensations for the central involuntary 'neural block'. Hence, by counting only perceptible portions of the disorder, efficacy measures 'fail to capture' the experiential sense of 'loss of control' and the covert compensatory behaviours of the disorder (i.e. avoidances of words or situations, substitutions, circumlocutions, subperceptual stuttering forms, etc.). Furthermore, unnatural sounding speech, decreased ease of speech production, elevated levels of clinic room fluency and poor reliability in counting stuttering behaviours confound the overt measures in the clinic milieu. Therefore, while overt measures remain important, used in isolation, they cannot provide a 'true metric' of efficacy. Any efficient and effective means of evaluating intervention methods over the long-term should include a form of self-report as a primary tool as it best accesses the experiential sense of 'loss of control' and other covert behaviours. Overt measures should be used to supplement or complement the self-report data.

Neuroscience Letters, 2003

We explored a possible temporal window for central stuttering inhibition via exogenously presente... more We explored a possible temporal window for central stuttering inhibition via exogenously presented speech signals. Thirteen adults who stutter were asked to read while listening to a continuous vowel /a/, or a repeating 1 s vowel /a/ followed by 1, 3 and 5 s silences. In all conditions, stuttering was significantly reduced. However, the continuous and 1 s repeating conditions showed the greatest reduction in stuttering relative to all other conditions. Furthermore, these conditions did not differ significantly from each other, suggesting a temporal window of at least 1 s for stuttering inhibition induced by a 1 s stimulus. We propose that exogenous speech signals provide an additional speech source that engages mirror neurons for 'on-line' stuttering inhibition during continous speech. Employing dual speech sources results in 'on-line' stuttering inhibition and continuous speech flow. In contrast, endogenous (single source) inhibitory techniques require speech flow to be interrupted and go 'off-line' to derive the mirror neuronal inhibition. q

International Journal of Language & Communication Disorders, 2004

Background: Self-contained ear-level devices delivering altered auditory feedback (AAF) for the a... more Background: Self-contained ear-level devices delivering altered auditory feedback (AAF) for the application with those who stutter were only recently developed .

Folia Phoniatrica Et Logopaedica, 2009

This study assessed the impact of stuttering via a questionnaire in which fluent individuals were... more This study assessed the impact of stuttering via a questionnaire in which fluent individuals were asked to assume the mindset of persons who stutter (PWS) in various life aspects, including vocation, romance, daily activities, friends/social life, family and general lifestyle. The perceived impact of stuttering through the mind's eyes of nonstutterers is supposed to reflect respondents' abilities to impart 'theory of mind' in addressing social penalties related to stuttering. Ninety-one university students answered a questionnaire containing 56 statements on a 7-point Likert scale. Forty-four participants (mean age = 20.4, SD = 4.4) were randomly selected to assume a stuttering identity and 47 respondents (mean age = 20.5, SD = 3.1) to assume their normally fluent identity. Significant differences between groups were found in more than two thirds of items regarding employment, romance, and daily activities, and in fewer than half of items regarding family, friend/social life, and general life style (p <0.001). The social penalties associated with stuttering appear to be apparent to fluent individuals, especially in areas of vocation, romance, and daily activities, suggesting that nonstuttering individuals, when assuming the role of PWS, are capable of at least temporarily feeling the negative impact of stuttering.

International Journal of Language & Communication Disorders, 2009

Background: Previous studies have found simultaneous increases in skin conductance response and d... more Background: Previous studies have found simultaneous increases in skin conductance response and decreases in heart rate when normally fluent speakers watched and listened to stuttered speech compared with fluent speech, suggesting that stuttering induces arousal and emotional unpleasantness in listeners. However, physiological responses of persons who stutter observing stuttering and fluent speech has not been measured. Research suggests that the mechanism responsible for listeners' reactions is the mirror neuron system. The mirror neuron system activates when perceiving and producing goal-directed actions and forms the link between action perception and action production. Aims: To compare physiological responses elicited via fluent and stuttered speech in fluent and persons who stutter groups.

International Journal of Neuroscience, 2004

Stuttering can be effectively inhibited via exogenous sensory signals (e.g., speaking in unison o... more Stuttering can be effectively inhibited via exogenous sensory signals (e.g., speaking in unison or using altered auditory feedback) or by using endogenous motoric strategies (e.g., singing or therapeutically implementing long vowel prolongations to reduce speech rates). We propose that these channels, which superficially appear to be diametrically opposite, centrally converge in the engagement of mirror neurons for fluent gestural productions. Sensory changes incurred via exogenous speech signals allow for direct engagement of mirror systems, while endogenous motor strategies appear to require significant departures from normal speech production (e.g., highly unnatural or droned speech) to engage mirror systems. Thus, paradoxically, stuttering is prone to resurface during attempts to impose naturalness upon therapeutic speech.

Journal of Clinical and Experimental Neuropsychology, 2004

This study examined fluency enhancement in people who stutter via the concomitant presentation of... more This study examined fluency enhancement in people who stutter via the concomitant presentation of silently mouthed visual speech. Ten adults who stutter recited memorized text while watching another speaker silently mouth linguistically equivalent and linguistically different material. Relative to a control condition, in which no concomitant stimulus was provided, stuttering was reduced by 71% in the linguistically equivalent condition versus only 35% in the linguistically different condition. Despite being an 'incomplete' second speech signal, visual speech possesses the capacity to immediately and substantially enhance fluency when it is linguistically equivalent to the intended utterance. It is suggested that fluency enhancement via concomitantly presented external speech is achieved through the extraction of relevant speech gestures from the external speech signal that compliment the intended production, thereby compensating for possible internal inconsistencies in the matching of speech codes in people who stutter. As visual speech perception relies on fewer redundant cues to demarcate the intended gestures, when used as an external stuttering inhibitor, higher degrees of linguistic equivalence seem to be necessary for optimal stuttering inhibition.