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.     

Adaptation effect in nonfluent speech behavior of controlled stutterers and nonstutterers

The adaptation effect in stuttering behavior has received considerable attention. Adaptation effect is defined as the reduction in the frequency of nonfluencies in the speech of subjects during successive readings of the same passage. The objective of this investigation was to assess the adaptation effect of nonfluent speech behavior of controlled stutterers and nonstutterers. The subjects included 35 controlled stutterers and 35 nonstutterers matched for factors of sex, grade level, and age. Results suggest a significant mean difference between the number of nonfluencies between trials of controlled stutterers with evidence of adaptation in the speech of nonstutterers. Nonstutterers demonstrate significant mean differences in nonfluencies among replicated testing occasions. Findings of this investigation suggest that both controlled stutterers and nonstutterers demonstrate similar adaptation regarding their nonfluent speech behavior. Issues and import for future research are offered.     

Voice reaction time of stuttering and nonstuttering children and adults

The voice reaction time (VRT) of 5-yr old, 9-yr old, and adult stutterers and nonstutterers was investigated. Subjects initiated the sound / Λ / in response to fifty-five 1000-Hz tones of 1 sec duration. The tones were presented in five equal sets of 11 tones each with the silent intervals between the tones randomly selected to be 3, 4, 5, or 6 sec. Data analysis was based on responses 2–11 for each set. The VRTs for both the stutterers and the nonstutterers decreased significantly as an inverse function of age, with the largest decrease in reaction time occuring between 5 and 9 yr. The VRTs for the stutterers, however, were significantly slower than those of the nonstutterers at each of the three age levels. The results suggest that observed disruption in the laryngeal behavior for at least some stutterers may not result from the development of stuttering with age, but may contribute to early difficulty in the child's ability to produce fluent speech. Consideration of central factors are discussed.     

Stuttering and anxiety: The difference between stutterers and nonstutterers in verbal apprehension and physiologic arousal during the anticipation of speech and non-speech tasks

To test if stressful anticipation of speech situations is a factor in eliciting stuttering behavior, the difference between 24 stutterers and 24 nonstutterers in verbal apprehension and physiologic activity was studied before and during speech tasks (reading and conversation), and nonspeech tasks (motor and intelligence task).Results indicate that the difference between stutterers and nonstutterers mainly were restricted to anxiety ratings assessed after each task. Heart rate, vasomotor responses, and electrodermal activity recorded before and during speech tasks were higher compared with the physiologic activity before and during nonspeech tasks but, unexpectedly, this was also the case for nonstutterers. It is concluded that stuttering is not elicited by anxiety.     

Unsophisticated judges' perceptual evaluations of the speech of “successfully treated” stutterers

The purpose of this investigation was to determine if the speech of “successfully therapeutized” stutterers and a group of partially treated stutterers was perceptually different from the speech of normal speakers when judged by unsophisticated listeners. Tape-recorded speech samples of treated stutterers were obtained from leading proponents 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. Fluent speech samples from these groups of stutterers were paired with matched fluent samples of normal talkers and presented to a group of 20 unsophisticated 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 showed that five of seven experimental groups were identified at levels significantly above chance. It can be concluded that the fluent speech of the partially and successfully treated stutterers was perceptibly different from the utterances of the normal speakers and that the perceptual disparity can be detected, even by unsophisticated listeners.     

A perceptual comparison between paired stimulus and single stimulus methods of presentation of the fluent utterances of stutterers

This investigation compared tape recordings containing the fluent utterances of treated stutterers with those of normal speakers as paired stimuli and single stimuli as presented to 20 sophisticated judges. Fluent utterances were obtained from stutterers successfully treated in one of the following programs: (1) Van Riperian, (2) metronome-conditioning speech retraining, (3) delayed auditory feedback, (4) operant conditioning, (5) precision fluency shaping program, and (6) holistic therapy. In addition, a group of partially treated stutterers were included. The original tape recordings containing matched samples of the fluent utterances of a stutterer and normal speaker were presented as paired stimuli. These paired samples were then separated, randomized, and assembled individually on another tape recording and presented as single stimuli to the same judges. The results of the statistical analysis indicated that the fluent utterances of treated stutterers was perceptibly different from the fluent utterances of nonstutterers, regardless of the method of stimulus presentation.     

A test of the distraction explanation of disfluency modification in stuttering

The distraction explanation of changes in stuttering rate was examined in the present experiment. Twelve stutterers were compared with 12 nonstutterers who were matched for age, sex, and level of education. Subjects were tested for disfluency production under conditions designed to reflect the dimension of distraction. These conditions were: (a) over attention to speech (counting speaking errors). (b) “normal” conditions (no additional task), and (c) distraction (pursuit tracking of an irregular target). The results showed no effect on stuttering rate that could be attributed to the distraction conditions. However, stutterers rated the difficulty of these conditions in concordance with the distraction theory. It was suggested that, while stutterers' perceptions may account for the popularity of the distraction explanation, evidence supporting the theory is lacking.     

Profiles of stutterers' and nonstutterers' affective, cognitive, and behavioral communication attitudes

The purposes of this investigation were 1) to profile the affective, cognitive, and behavioral attitudinal dimensions of stutterers' and nonstutterers' communication attitudes and 2) to describe membership characteristics of each profile. To this end, 76 stutterers and 81 nonstutterers completed the Inventory of Communication Attitudes. This self-report inventory obtained ratings of different types of speaking situations, using five response scales reflecting behavioral, affective, and cognitive aspects of attitudes. Exploratory cluster analysis identified six attitudinal clusters or profiles. Some profiles were more typical either of stuttering respondents or of nonstuttering respondents, whereas one profile reflected attitudes of proportionately equal numbers of stutterers and nonstutterers. Examination of profile membership characteristics revealed two significant discriminators, classification as a stutterer or nonstutterer and an overall speech rating. Nondiscriminatory characteristics included sex, age, education, therapy experiences, stuttering severity self-rating, onset of stuttering, total therapy time, current therapeutic status, and familial history.     

Reaction time for voiced and whispered /a/ in stutterers and nonstutterers

Recent research reviewed in this article suggests that stutterers' inability to initiate phonation promptly could be a significant factor in the occurence of stuttering. Since stuttering is either completely absent or markedly reduced in frequency during whisper, the present study tested the hypothesis that stutterers do not significantly differ from nonstutterers in reaction time (RT) for the initiation of whispered/a/, whereas the two groups differ significantly in RT for the initiation of voiced /a/. Ten adult stutterers and an equal number of comparable nonstutterers produced prolonged versions of the vowel /a/ using voice and whisper in response to tone stimuli. The results showed that stutteres and nonstutterers did not differ in RT for either voiced or whispered /a/. The stutterers, however, exhibited significantly longer RT to produce voiced /a/ than whispered /a/.     

A comparison of syntax in young stutterers and nonstutterers

This study compares the syntactic structure of the spontaneous speech of a small group of stutterers and nonstutterers, using a method of constituent analysis. Speech samples were taped during play sessions with subjects, and the tapes were then transcribed and analyzed according to preselected constituent criteria. The stutterers were in the early stages of stuttering and had been diagnosed as stutterers by experienced clinicians. The method of analysis proved to be highly reliable. Differences were found in the number of complete clauses, the number of complex sentences, and in clause types between the two groups.     

Voice onsets and segment durations of normal speakers and beginning stutterers

Longer VOT and segment durations apparently characterize the contrived responses of school-age stutterers examined under laboratory conditions. Thus, these variables may reflect basic disparities between the speech production abilities of stutterers and normal speakers. To better explore this possibility, VOT and segment durations were assessed in five nonstutterers who were closely matched with five preschool stutterers who had been diagnosed and tested in the experiment within six months of parental concern about fluency development. Target words were measured in isolation, in elicited sentences, and conversation. Results revealed significantly slower VOT and longer segment durations in the young stuttering members of the pairs of speakers. The stutterers were also more variable in their management of these same two aspects of motor speech timing control.     

Motor Performance of Stutterers and Nonstutterers on Timing and Force Control Tasks

Recently it has been suggested that speech and manual timing tasks share a common central process (Franz, Zelaznik, & Smith, 1992): Because stuttering is thought to be related to deficits in motoric processes such as timing, stutterers (n = 15) were compared with a set of age-, education-, and sex-matched nonstutterers on timing and isometric force-production tasks. In the timing tasks, subjects flexed and extended the right index finger at the metacarpophalangeal joint at cycle durations of 600, 500, 400, 300, and 200 ms. In the force-production tasks, subjects generated isometric forces to match target force levels displayed on a cathode-ray tube (CRT) screen. There were five levels of force, ranging from.11 to 7.85 newtons. Overall, there were no differences in timing and force-production performance between stutterers and nonstutterers. These results are similar to those obtained recently by Hulstijn, Summers, van Lieshout, and Peters (1992). We suggest that stuttering is not characterized by a general deficit in rhythmic timing. Instead, the motor deficit associated with stuttering should be viewed as speech specific.     

An analysis of speech disfluencies in down''s syndrome and in normally intelligent subjects

Spontaneous speech samples were obtained from 19 institutionalized mongoloids and from 19 normally intelligent individuals. All subjects were evaluated by a panel of speech pathologists to be nonstutterers. Subjects' speech samples were analyzed to determine (a) frequency of occurance of seven disfluency categories per 100 words spoken, (b) the proportion of each category in the total number of disfluencies. Statistically significant differences indicated that the mongoloids were more disfluent both absolutely and relatively, on categories that have been regarded as most typical to speech of stutterers. Interpretations were made to reflect on factors which may enhance the high prevalence of stuttering among Down's Syndrome patients.     

Motor Performance of Stutterers and Nonstutterers on Timing and Force Control Tasks

Recently it has been suggested that speech and manual timing tasks share a common central process (Franz, Zelaznik, & Smith, 1992). Because stuttering is thought to be related to deficits in motoric processes such as timing, stutterers (n = 15) were compared with a set of age-, education-, and sex-matched nonstutterers on timing and isometric force-production tasks. In the timing tasks, subjects flexed and extended the right index finger at the metacarpophalangeal joint at cycle durations of 600, 500, 400, 300, and 200 ms. In the force-production tasks, subjects generated isometric forces to match target force levels displayed on a cathode-ray tube (CRT) screen. There were five levels of force, ranging from .11 to 7.85 newtons. Overall, there were no differences in timing and force-production performance between stutterers and nonstutterers. These results are similar to those obtained recently by Hulstijn, Summers, van Lieshout, and Peters (1992). We suggest that stuttering is not characterized by a general deficit in rhythmic timing. Instead, the motor deficit associated with stuttering should be viewed as speech specific.     

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.     

Personal constructs of fluency: a study comparing stutterers and nonstutterers

The personal construct systems relating to fluency of a group of five stutterers and a group of five nonstutterers were examined using the repertory grid technique. The results support findings that stereotypical notions about stuttering were characteristic of both stutterers and nonstutterers and did not support Fransella's 1972 assumption that constructs relating to fluency differ in the communication subsystems of stutterers and nonstutterers.     

The voice problems of stutterers: A practical approach from clinical experience

Voice disorders, which may be caused by the stuttering problem, have been noted in at least one-third of stutterers seen. Basically, stutterers have false speech images that normal speech is perfect and without natural dysfluencies (repetitions, pauses, etc.). Many stutterers also have erroneous vocal images of how they should or should not sound. Both images control speech and voice. Clinical experience indicates that vocal rehabilitation should be used in conjunction with speech therapy for many stutterers.     

Variability in the initiation of articulatory movements in the speech of stutterers and normal speakers

This study was designed to investigate the differences between stutterers and normal speakers in phonatory and articulatory timing during the initiation of fluent utterances of monosyllabic words. Electromyographic recordings of four articulatory muscles and recordings of glottal vibrations were made of repetitive utterances of a series of monosyllabic words by 15 stutterers and 17 nonstutterers. These data were analyzed in terms of average interval times between voice onset and onset of EMG activity and between onset of EMG activity in each articulator and in terms of the intrasubject variability of these durational measures. Results showed that there were no significant differences between stutterers and nonstutterers in average interval times and that stutterers, in general, were significantly more variable in their speech onset timing. Findings are discussed in terms of recent hypotheses concerning the role of timing disturbances as the main source of speech disruption in stutterers.     

An evaluation of the effects of supplemental “fluency” training during maintenance

The voice onset time (VOT) of two groups of treated stutterers and a normal-speaking group was assessed by spectrographic analysis. Both groups of stutterers had significantly slower VOT than the normal speakers. The experimental group of stutterers was given 8 wk of “fluency” training designed to remediate characteristics of speech identified as related to “tenuous” fluency. The control group of stutterers received ongoing maintenance therapy. Posttreatment VOT was assessed. The experimental stuttering group had significantly decreased their VOT in the direction of the normal-speaking group, whereas the control group of stutterers had a greater VOT between pre- and posttreatment. The implication of these results for the maintenance of fluency are discussed.