Influence of stuttering therapy on clinicians'' disfluencies: Effects of client modeling

This study investigated whether student clinicians working with stutterers subsequently produce more disfluencies than student clinicians providing therapy to clients with other speech and language disorders. Seventeen graduate students working in a 6-wk summer camp setting were divided into two groups: eight who provided treatment for stutterers (group 1) and nine who provided therapy for clients with other communication disorders (group 2). All student clinicians were recorded during spontaneous speaking and oral reading tasks prior to camper arrival and following camper departure. An eight-category classification system was used to determine disfluency types. Findings revealed that Group 1 clinicians significantly decreased their total disfluencies between pre- and post-camp recordings on the spontaneous speaking task. Unexpectedly, this same group also substantially increased part-word repetitions and sound prolongations. The possibilities of incidental learning, reverse modeling, and overidentification with stuttering clients are discussed.     

Vocal changes in stutterers and nonstutterers during monotoned speech

For years, reports have circulated that stutterers experience marked decrements in their stuttering when they speak or read in monotone. Wingate has suggested that the ameliorative effects of various novel speaking conditions on stuttering can be attributed to modifications in vocalization induced by such conditions. The present study was conducted to see whether this explanation would extend to monotoned speech as well. Ten teenage and adult stutterers and 10 normal speakers were tested in control and monotone reading conditions. Dependent measures were the frequencies of disfluency and stuttering, fundamental frequency, fundamental frequency standard deviation, vocal SPL, vocal SPL standard deviation, and fluent reading rate. Only within-group statistical comparisons were made, because members of the two groups could not be matched pairwise along critical vocal parameters. The major findings of this study indicated that across the two conditions, both groups significantly reduced their fundamental frequency, fundamental frequency standard deviation, vocal SPL and vocal SPL standard deviation. Only the stutterers exhibited a significant decrement in disfluency and stuttering. The normals did not evince enough disfluency in the control condition for a reduction to occur during monotoning. Neither group effected a reduction in fluent reading rates. These and other findings and interpretations are discussed relative to Wingate's modified vocalization hypothesis.     

Pause time and phonation time in stuttering and cluttering

This study examined the potential usefulness of automated analysis of on-off speech patterns in the differentiation of stuttering from cluttering. Two groups of fifteen persons who had been previously classified as stutterers and clutterers served as subjects for this investigation. The data indicate that stutterers tend to have greater mean pause times and lower mean phonation times than clutterers. This result corresponds to the clinically observable characteristics of these groups. It is concluded that automated analysis of on-off speech patterns provides some basis for the differential diagnosis of stuttering from cluttering.Supported, in part, by a general research support grant from NIMH to the Research Foundation for Mental Hygiene, Inc.     

Rate reduction strategies used by stutterers and nonstutterers during high- and low-pitched speech

Groups of child and adult normal speakers and stutterers were tested in an habitual condition and in conditions where they were instructed to read aloud at pitches both higher than and lower than normal. Objective measures were made of subjects' fluent reading rate, and vowel and pause durations across conditions. Disfluencies were also counted. Findings revealed that all four subject groups reduced their frequency of disfluency from the habitual to both experimental conditions. These decrements in disfluency were attended by significant reductions in fluent reading rate. Spectrographic analyses revealed that most subjects, regardless of age and speaker characteristic, affected their rate reduction by extending both vowel and pause durations. These results are compatible with those obtained in recent studies and are discussed.     

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.     

Disfluency characteristics of 2-, 4-, and 6- yr-old males

Fluency characteristics of 36 nonstuttering males aged 2, 4, and 6 yr are presented in terms of patterns of disfluency and relationships among disfluency variables. The most frequently occuring disfluency types at each age level were revision-incomplete phrase and interjections; the least noted type was part-word repetitions for 2- and 4-yr olds and disrhythmic phonations for 6-yr-olds. Patterns of disfluency appear to be similar at all age levels studied, except that the 2-yr-old pattern showed greater magnitudes in various disfluency types. A range exists in the relationships among individual disfluency types, from moderately strong relationships between, for example, revision-incomplete phrase and interjections to lack of linear relationships between, for example, interjections and phrase repetitions. A linguistic factor may be strong within certain disfluency types. e.g., revision-incomplete phrase, interjections, and word repetitions, whereas a motor factor may be operative in others, e.g., part-word repetitions and disrhythmic phonations.     

Vocal changes in stutterers and nonstutterers when speaking to children

Within the last few years, considerable attention has been devoted to the possibility that the amelioration of stuttering in many novel speaking conditions is a function of vocal changes with or without accompanying modifications in prosodic expression. These formulations have made reference primarily to conditions in which stutterers were induced into one or another novel speech pattern by an external stimulus such as masking noise, a rhythmic cue, or by instructions to sing, or read in unison with another speaker. In contrast, far less attention has been paid to other ameliorative conditions that lack a novel external stimulus or special instructions that direct the stutterer to speak in some unique manner. Speaking or reading to a child is an example of this latter type of condition. The present study was conducted to see if nine adult stutterers and a matched group of nonstutterers would evince vocal changes as they read aloud to another adult, a child, and a child and adult together. There was also a fourth control condition wherein the subjects read to one of the experimenters. Dependent measures of disfluency and stuttering, fundamental frequency, fundamental frequency deviation, fluent reading rate, and peak vocal sound pressure level were made and treated statistically. The major findings of this study indicated that, relative to the control condition, both subject groups exhibited several vocal changes when reading to a child alone and to a child and adult together. In addition, the stutterers experienced a reduction in disfluency, but only when reading to the child alone. The normal speakers exhibited too few disfluencies in the control condition for any meaningful change to occur in that dependent variable. The fact that the stutterers evinced vocal changes in both experimental conditions but a significant drop in disfluency in just one bears importantly on hypotheses that emphasize vocal changes in conditions that ameliorate stuttering.     

Vocal changes in stutterers and nonstutterers during high- and low-pitched speech

This study was conducted to provide an indirect test of Wingate's “modified vocalization” hypothesis. In this formulation, the improved fluency that stutterers experience in various novel conditions is attributed to changes in the key correlates of stress, namely, fundamental frequency, vocal SPL, and rate.Normal speakers and stutterers read aloud in an habitual condition following instructions to read at higher- and lower-than-normal pitches. Objective measures were taken of subjects' fundamental frequency, fundamental frequency deviation, vocal SPL, and fluent reading rate. Disfluences were also counted. Findings showed that both stutterers and normals altered several features of voicing from the habitual to the two experimental conditions. Significant condition main effects emerged for fundamental frequency deviation, vocal SPL, fluent reading rate, and disfluency. The only meaningful between-group difference noted showed that the stutterers were more disfluent than the normals across all conditions. Results were interpreted as supporting Wingate's “modified vocalization” position and were discussed relative to how the vocal changes observed might act to promote fluency.     

Attention and stuttering: Do stutterers think too much about speech?

In this investigation the ability of stutterers and nonstutterers to simultaneously perform speech and nonspeech tasks was compared. Subjects were 10 stutterers and 10 nonstutterers. Two experiments were conducted. In the first, subjects performed a non-attention-demanding gross-motor task while they read aloud. In the second, subjects performed an attention-demanding task (reading comprehension) during speech. Results indicated that there was no significant change in the disfluency values of stutterers during the motor activity or as a result of the reading comprehension task. However, stutterers were found to perform significantly poorer than nonstutterers on the reading comprehension task. This finding was taken as evidence that stutterers devote more attention to speech than do nonstutterers.     

Vowel duration in stutterers participating in precision fluency shaping

The purpose of this study was to determine the extent to which stutters manipulate vowel duration to achieve fluency after participating in Precision Fluency Shaping. Nine stutterers who read an all-voiced sentence fluently before and after therapy were selected for study. Wide-band spectrograms were made of the initial phrase of the sentences, and vowel durations were computed. Results indicated that extended vowel durations were characteristic of the fluency of stutterers posttherapy. The subject that had the highest rate of disfluency after therapy also had the shortest vowel durations. Clinical implications concerning the importance of speech rate during carryover practice are made.     

Word fragmentations and repetitions in the spontaneous speech of 2–6-yr-old children

Samples of spontaneous speech of 110 nursery school children, aged 2 yr, 1 mo to 6 yr, were written down. Two of the children were regarded as stutterers by the parents and the nursery school personnel. Instances of word and phrase repetitions and word fragmentations were marked. Fragmentation of a word before the whole word is pronounced was used as criterion of stuttering. The nonstutterers had an average frequency of word repetitions of 6.3%, while word fragmentations were virtually nonoccurrent. The frequency of word repetitions decreased with increasing age. Relating word repetitions to grammatical complexity of speech, it was found that the decrease was particularly large at a certain point of the grammatical development. The two stutterers had, in addition to normal frequencies of word repetitions, marked occurences of word fragmentations (2.8 and 4.1%).     

Listener ratings of severity for specific disfluency types in children

This study investigated whether some types of disfluency are perceived as more severe than others and if listener groups differ in their perception of severity for some disfluency types. Three normal speaking children were trained to produce eight types of disfluency and one sample of fluency. The experimental tape, consisting of three examples for each of the eight disfluency types and of fluency, was presented auditorily to 40 judges divided into four groups of 10 each: parents of stutterers, parents of nonstutterers, speech clinicians, and elementary school teachers. The judges rated the disfluency and fluency on a 15-point severity continuum, divided into four nominal categories of Fluent, Normal Disfluency, Mild Stuttering, Moderate Stuttering, and Severe Stuttering. Results showed that although listener groups did not significantly differ in their severity ratings, the specific types of disfluency did differ significantly. The type of disfluency emitted by a speaker is apparently more salient in perceiving and judging disfluency than the type of listener making the judgment.     

Speech and bimanual hand organization in adult stutterers and nonstutterers

A multivariate approach was used to investigate the relationship between speech fluency and bimanual handwriting in right-handed male stutterers and nonstutterers. Handedness was determined by the Harris Test of Lateral Dominance. Subjects were required to write the numbers 1 through 12 simultaneously, as quickly as possible. Speech measures were derived from the Stuttering Severity Instrument and from a reading passage. Stutterers performed more poorly than nonstutterers on all speech measures. There were no differences in bimanual handwriting performance for the dominant hand. However, stutterers performed more poorly than nonstutterers in nondominant handwriting. There were no relationships between speech measures and bimanual handwriting for stutterers or nonstutterers. Some stutterers performed better on the handwriting task than did some nonstutterers. It is suggested that disorganization in interhemispheric integration functions may be a more fundamental problem in stuttering than is incomplete cerebral dominance.     

Perceptual study of the speech of “successfully therapeutized” stutterers

The purpose of this investigation was to determine if the fluent speech of “successfully therapeutized” stutterers and a group of partially treated stutterers was perceptually different from the fluent speech of normal speaking subjects. Tape recorded speech samples of treated stutterers were obtained from leading exponents of (1) Van Riperian, (2) metronome-conditioned speech retraining, (3) delayed auditory feedback, (4) operant conditioning, (5) precision fluency shaping, and (6) “holistic” therapy programs. All forms of disfluency were edited out of these tapes. The remaining samples were then paired with matched fluent samples of normal talkers and presented to a group of 20 sophisticated judges. The judges were instructed to select from each paired speech sample presented to them the one produced by the stuttering subject. The results of the analyses of variance for correct identification of the stutterers showed that the partially treated stutterers, as well as each group of therapeutized stutterers, were identified at levels significantly above chance. This meant that the fluent speech of the partially and successfully treated stutterers was perceptibly different from the utterances of the normal speakers sampled. In addition, the analyses of variance also revealed that all stuttering groups had a significant severity factor. This finding indicated there was a significant difference between the severity subgroup in all the samples investigated. These results were discussed in terms of their clinical implications.     

Speech errors, disfluencies, and self-repairs of stutterers in two accuracy conditions

The purpose of the present study was to see whether the covert repair hypothesis, which views normal disfluencies as the by-products of covert self-repairing of internal speech (programming) errors, applies to habitual stutterers. To this end, we examined the effects of emphasis on speech accuracy in stutterers on three sorts of incidents: speech errors, disfluencies (also including stuttering), and self-repairs. In a condition in which they performed a speech task under instructions stressing the accuracy of speaking, stutterers made considerably fewer speech errors, than in a condition in which speech accuracy could be ignored. On the other hand, disfluency and self-repair rates remained about the same. They did increase, however, relative to speech error rates with accuracy emphasis. A control group of normal speakers performed in a similar way. Apparently, disfluencies behaved like self-repairs. These results support the covert repair hypothesis of disfluency, both for stutterers and for normal speakers.     

Auditory processing and perceptual abilities of “organic” and “functional” stutterers

The present investigation was undertaken to determine whether significant differences in auditory processing and perceptual abilities exist between (1) stutterers as a supposedly homogeneous group when compared with controls, (2) two differentiated subgroups of stutterers, and (3) either of the stuttering subgroups when separately compared with controls. Dichotic listening and masking level difference (MLD) tasks were administered to the two groups of school-age stutterers and an age-matched nonstuttering control group. Stuttering subjects were differentiated into “organic” and “functional” subgroups on the basis of neuropsychological test performances. Organic stutterers performed significantly poorer than did controls on one MLD experimental condition. Functional stutterers performed more like control subjects than like organic stutterers.     

Assessment of stuttering in a familiar versus an unfamiliar language

The present study investigated how well individuals knowledgeable about stuttering are able to make disfluency judgments in clients who speak another language than their own. Fourteen native speakers of Brazilian Portuguese identified and judged stuttering in Dutch speakers and in Portuguese speakers. Fourteen native speakers of Dutch identified and judged stuttering in Brazilian Portuguese speakers and in Dutch speakers. It was found that judges can make similar level of judgment in a native and a foreign language, and that native and foreign judges can make similar level of judgment irrespective of native/foreign differences. It was also found, however, that the Dutch judges performed significantly better in identifying native stutterers than foreign stutterers. And for the identification of nonstutterers, both panels performed better in their native language than in the foreign language, and in their native language they both performed better than the other panel. Both the Brazilian Portuguese and the Dutch speaking panel were generally also less confident, and found identification of stuttering more difficult in the foreign language than in the native language. In addition, when asked for the characteristics that helped them identify stutterers, they provided more detail in the native language than in the foreign language. Also a number of differences were found between the two panels which may be due to differences in training or cultural background. The implications of the findings for clinical practice and for future research in this area are discussed. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) describe how language influences the identification of a speech disorder such as stuttering, and (2) list, and (3) define behaviors that help to identify stuttering in a foreign language.     

Effect of threat of shock for being disfluent of fluency of normal speakers.

Each of 20 adult nonstutterers read a 330-word passage six times with a one minute pause between readings. Between the third and fourth reading or the fifth and sixth reading (determined by a table of random numbers) Ss were informed that at the conclusion of the next reading an electric shock would be administered for each instance of disfluency detected by E during that reading. Ss did not become less fluent as a consequence of the experimental condition. Their mean disfluency frequency during the threat-of-shock reading was lower than during the preceding one. Thus, threat of shock for being disfluent may be a condition which differentiates stutterers from nonstutterers since stutterers have been reported to become less fluent under this condition.