Perceptual analyses of stuttering and nonstuttering children's fluent speech productions

Several investigators have reported a significant perceptual difference between adult stutterers' and nonstutterers' fluent speech productions. However, there is only limited information concerning the perceptual evaluation of stuttering and nonstuttering children's fluent speech. Therefore, in this study identical fluent sentences from nine stuttering children (mean age = 6 yrs, 8 mos) and nine nonstuttering children matched individually for sex and age (within 6 mos) were analyzed perceptually in both a paired- and single-stimulus paradigm by 12 sophisticated listeners. Individual subject analyses revealed that only one-half or fewer of the stutterers could be discerned in either paradigm. In the remaining cases, either no discrimination could be made or a nonstutterer was incorrectly identified as a stutterer. When averaged for subject group comparison, these findings indicated that listeners could not discriminate between the two groups. Possible explanations for this discrepancy in results between child and adult stutterers are proposed.     

The precision fluency shaping program: Replication and evaluation

The purpose of this article is to present the results of a two-year project to evaluate the Precision Fluency Shaping Program (Webster, 1980) in a community speech and hearing center. Fifty stutterers participated in therapy. Results indicated that Precision Fluency Shaping was an effective therapy for the treatment of stuttering. In addition, stutterer's perception of their speech changed from pre to post therapy. Follow-up data are presented on 28 clients. Advantages of conducting Precision Fluency Shaping, meeting accountability standards, and procedures for collecting follow-up data are discussed.     

Perceptual fluency and affect without recognition

A dichotic listening task was used to investigate the affect-without-recognition phenomenon. Subjects performed a distractor task by responding to the information presented in one ear while ignoring the target information presented in the other ear. The subjects' recognition of and affect toward the target information as well as toward foils was measured. The results offer evidence for the affect-without-recognition phenomenon. Furthermore, the data suggest that the subjects' affect toward the stimuli depended primarily on the extent to which the stimuli were perceived as familiar (i.e., subjective familiarity), and this perception was influenced by the ear in which the distractor or the target information was presented. These data are interpreted in terms of current models of recognition memory and hemispheric lateralization.     

Women''s liberation, stuttering, and the concern for fluency

At a large urban speech and hearing center, the sex ratio of male to female stutterers was found to be decreasing, showing that more female stutterers were referring themselves or being referred for treatment. This may or may not indicate that the women's liberation movement is having a deleterious effect on stuttering incidence for females. However, it may indicate more of a concern for fluency among females when compared to males. The study could be an indication that concern for fluency among upward striving females should be studied in more depth.     

Past speech therapy experiences of individuals exploring a new stuttering treatment

Perceptions of benefits of speech therapy, success of therapy across clinical settings, reasons for returning to therapy, client-clinician relationships, and clinicians' competency were assessed in 57 participants (47 men, 10 women; M age = 34 yr.) trying a new therapy. A majority of respondents had cumulatively five or more years in therapy and at least two stuttering therapies. Respondents rated university or hospital settings as more successful than services in public schools. 70% of the respondents noted difficulty communicating basic needs; they blamed themselves for inability to maintain posttherapeutic gains while perceiving their clinicians to be competent and attentive--although 47% of the respondents had minimal to no contact with their therapist after therapy.     

Syntactic determinants of stuttering in the spontaneous speech of normally fluent and stuttering children

Conflicting findings have been reported concerning whether fluent children use more complex syntactic structures than stutterers and whether or not stutterers experience specific difficulty with complex syntactic structures. On critical examination, the first of these apparent discrepancies appears to be due to (a) differences in the methods employed for syntactic analysis in different studies, and (b) misleading impressions gained by looking at speakers within a single age range. Data were reanalyzed where one method of analysis had shown that fluent speakers and stutterers did not differ with regard to syntactic structures used but where they did show a propensity for stuttering to occur on complex syntactic structures. These data cover a range of age groups. When the second method of syntactic analysis was applied, a difference was found between fluent speakers and stutterers, with the stutterers initially using more simple structures and fewer complex ones. This difference decreased over age groups. However, a difference still remained with respect to which syntactic structures stutterers experience difficulty. An additional analysis, not formerly conducted on these data, showed that, as reported elsewhere, there was a higher probability of stuttering on clause-initial and. It was also shown that this tendency decreased with age group of the stutterers.     

Nonstutterers'' perceptions of stuttering and speech difficulty

Two versions of Woolf's (1967) Perception of Stuttering Inventory (PSI) were administered to nonstuttering college students in three experiments. In one (Woolf's published version) the word “stuttering” appeared and in another [a version developed by Daly, Oakes, Breen, and Mishler (1981)] “stuttering” was replaced by “speech difficulty.” Nonstutterers' scores on the PSI were found to be affected by knowledge of—or attention to—“stuttering” or “stutterers” as well as orientation toward speech or speech pathology. It was concluded that a total PSI score of 5 is presently a more defensible criterion of normality for stutterers than the more commonly used score of 10.     

Critical words and the locus of stuttering in speech

The locus of stuttering in the communicative speech of 26 stutterers was studied in situations where subjects received and conveyed specific information. It was hypothesized that a larger proportion of critical rather than noncritical words would be stuttered. Critical words were those which necessarily had to be pronounced if a listener should be able to understand and act according to the messages given. The critical words were selected by the experimenter before the experiment started. The results showed that 35.8% of the critical and 8.4% of the noncritical words were stuttered. There was also significantly more stuttering on critical words than on long noncritical words. The largest proportion of critical words appeared in the final position of sentences, which was also where most stuttering was located. Whole-word repetitions, an instance of normal nonfluency, were associated with noncritical words. No correlation between frequency of stuttering and whole-word repetitions was found.     

Voluntary stuttering suppresses true stuttering: a window on the speech perception-production link

In accord with a proposed innate link between speech perception and production (e.g., motor theory), this study provides compelling evidence for the inhibition of stuttering events in people who stutter prior to the initiation of the intended speech act, via both the perception and the production of speech gestures. Stuttering frequency during reading was reduced in 10 adults who stutter by approximately 40% in three of four experimental conditions: (1) following passive audiovisual presentation (i.e., viewing and hearing) of another person producing pseudostuttering (stutter-like syllabic repetitions) and following active shadowing of both (2) pseudostuttered and (3) fluent speech. Stuttering was not inhibited during reading following passive audiovisual presentation of fluent speech. Syllabic repetitions can inhibit stuttering both when produced and when perceived, and we suggest that these elementary stuttering forms may serve as compensatory speech gestures for releasing involuntary stuttering blocks by engaging mirror neuronal systems that are predisposed for fluent gestural imitation.     

Perceptual independence in the perception of speech

The purpose of the experiments and analyses was to discover whether the “independence” model, which successfully accounts for the perception of synthetic multi-dimensional stimuli, would also describe the perception of speech in noise. Two sets of four words were chosen which could be considered phonetically to be describable in terms of two dimensions. The S/R matrix was analysed as if the stimuli were bi-dimensional elementary stimuli. Satisfactory fits were obtained by the independence model. Two analyses were conducted upon data from Miller and Nicely (1955) and Conrad (1964) to discover whether the perception of phonemes was also predictable on the independence model. In general this was found to be the case.     

The effects of simulated stuttering and prolonged speech on the neural activation patterns of stuttering and nonstuttering adults

Functional magnetic resonance imaging was used to investigate the neural correlates of passive listening, habitual speech and two modified speech patterns (simulated stuttering and prolonged speech) in stuttering and nonstuttering adults. Within-group comparisons revealed increased right hemisphere biased activation of speech-related regions during the simulated stuttered and prolonged speech tasks, relative to the habitual speech task, in the stuttering group. No significant activation differences were observed within the nonstuttering participants during these speech conditions. Between-group comparisons revealed less left superior temporal gyrus activation in stutterers during habitual speech and increased right inferior frontal gyrus activation during simulated stuttering relative to nonstutterers. Stutterers were also found to have increased activation in the left middle and superior temporal gyri and right insula, primary motor cortex and supplementary motor cortex during the passive listening condition relative to nonstutterers. The results provide further evidence for the presence of functional deficiencies underlying auditory processing, motor planning and execution in people who stutter, with these differences being affected by speech manner.     

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.     

Rate changes in the speech of stutterers after therapy

The fluent speaking rate of nine adult male stutterers was compared before and after stuttering intervention. The subjects, ranging in age from 18 to 37 yr (mean, 25 yr, 3 mo), exhibited mild to severe stuttering prior to treatment. The only rate reduction strategy taught to subjects during intervention was to slow the first phoneme or syllable of sentences spoken. In addition, however, subjects significantly reduced their overall rate as determined by measurements made of their fluent speech at the middle of sentences, as well as overall sentence durations (excepting the first word of utterances). The data from this investigation are interpreted relative to the facilitation/simplification hypothesis.     

The maintenance of fluency after intensive in-patient therapy: Long-term follow-up

Maintenance of fluency after intensive in-patient treatment was studied in eight male stammerers. Reasons for success and failure are discussed in relation to objective and subjective data collected at the final follow-up interview.     

Impairments of speech fluency in Lewy body spectrum disorder

Few studies have examined connected speech in demented and non-demented patients with Parkinson’s disease (PD). We assessed the speech production of 35 patients with Lewy body spectrum disorder (LBSD), including non-demented PD patients, patients with PD dementia (PDD), and patients with dementia with Lewy bodies (DLB), in a semi-structured narrative speech sample in order to characterize impairments of speech fluency and to determine the factors contributing to reduced speech fluency in these patients. Both demented and non-demented PD patients exhibited reduced speech fluency, characterized by reduced overall speech rate and long pauses between sentences. Reduced speech rate in LBSD correlated with measures of between-utterance pauses, executive functioning, and grammatical comprehension. Regression analyses related non-fluent speech, grammatical difficulty, and executive difficulty to atrophy in frontal brain regions. These findings indicate that multiple factors contribute to slowed speech in LBSD, and this is mediated in part by disease in frontal brain regions.     

The relevance of DAF-induced speech disruption to the understanding of stuttering

The literature on delayed auditory feedback (DAF) repeatedly makes reference to the occurence of disfluencies under DAF in nonstutterers. However, no attempt has been made to determine the relative frequency of occurence of various types of disfluencies in nonstutterers under DAF. The present study investigated the frequency of occurence of various types of disfluencies in normal-speaking subjects in five successive oral readings under DAF. Twenty-four young adults read aloud a prose passage five times successively under 200 msec of bilateral DAF. Measures of the frequency of different types of disfluencies, locus of occurence of disfluencies in the speech sample, adaptation and consistency indicate that DAF-induced disfluencies are remarkably similar to those found in stuttering. It is suggested that DAF and stuttering disrupt speech at approximately the same “level” along the speech production process, possibly at the prosodic level.