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.     

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.     

Motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task

The issue of handedness has been the topic of great interest for researchers in a number of scientific domains. It is typically observed that the dominant hand yields numerous behavioral advantages over the non-dominant hand during unimanual tasks, which provides evidence of hemispheric specialization. In contrast to advantages for the dominant hand during motor execution, recent research has demonstrated that the right hand has advantages during motor planning (regardless of handedness), indicating that motor planning is a specialized function of the left hemisphere. In the present study we explored hemispheric advantages in motor planning and execution in left- and right-handed individuals during a bimanual grasping and placing task. Replicating previous findings, both motor planning and execution was influenced by object end-orientation congruency. In addition, although motor planning (i.e., end-state comfort) was not influenced by hand or handedness, motor execution differed between left and right hand, with shorter object transport times observed for the left hand, regardless of handedness. These results demonstrate that the hemispheric advantages often observed in unimanual tasks do not extend to discrete bimanual tasks. We propose that the differences in object transport time between the two hands arise from overt shifting visual fixation between the two hands/objects.     

Speech disfluencies in nonstutterers Syntactic complexity and production task effects

The differences in the number of disfluencies of 3-, 5-, and 7-year-old nonstuttering children were investigated as syntactic complexity was varied in three different syntactic constructions: 1) simple affirmative declarative with copula + ing (SAAD), 2) future (FUT), and 3) passive (PAS) within a sentence imitation and a sentence-modeling task. The subjects repeated 30 sentences from the imitation task stimuli and produced response constructions from 30 pictures from the modeling task stimuli. The 3-year-olds exhibited significantly more disfluencies than the 5-year-olds, and the 5-year-olds produced significantly more disfluencies than the 7-year-olds. All three age groups produced significantly more disfluencies on the modeling task than on the imitation task. A significant complexity effect was demonstrated for the PAS construction. Results are compared to previous research findings and discussed with reference to hypothesized linguistic complexity and task difficulty.     

Motor perseverative behavior in adult stutterers and nonstutterers

The performances of 22 adult stutterers and 22 adult nonstutterers on motor tasks requiring the graphic reproduction of a sequence of alternating figures following the production of a series of nonalternating figures were studied. The finding that there were no differences in the performance of the two groups on the alternating motor tasks was interpreted as challenging the validity of previous observations that motor perseverative behavior exists in stutterers and is indicative of a central neurological deficit in that population.     

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.     

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.     

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.     

Comparing performance by parents and offspring on a rapid tapping task

The purpose of this study was to identify the relationships between 42 parents' and their offsprings' performance on a rapid tapping task. It was expected that genetic predispositions would gradually limit children's performance on a tapping task as they matured chronologically. Four different age groups of children and their parents performed the tapping task on different sizes of boards. Repeated-measures analysis of variance indicated that, while parents' mean performance was generally higher than that of their children (F = 32.89, p < .001), the difference was affected by the children's age, which hand was used, and the board size. Spearman rank correlation scores between parents' and children's overall performances gradually increased across age groups (p = -.29, -.10, .47, and .40, respectively, from younger to older age groups). This finding suggests that the potential of youngsters' future performance may be predicted with greater certainty by observing their parents' present performance. This may improve the predictive power of planned programs.     

Stereotypes of stutterers and nonstutterers in three rural communities in Newfoundland

The existence of a negative stereotype of stutterers among residents of three small, rural communities in Newfoundland, Canada was investigated. Members of these communities (n = 106) completed a 25-item semantic differential scale developed by Woods and Williams (1976) which asked them to rate a hypothetical adult male stutterer and nonstutterer. Results indicated that community members perceived hypothetical stutterers in a negative manner in comparison to nonstutterers, despite the fact that 85% of the respondents reported knowing stutterers and 39% reported being related to stutterers. It is suggested the negative stuttering stereotype exists because nonstutterers generalize state to trait anxiety, and because of the nature of the stuttering moment itself. Since this study and previous studies appear to show that the stereotype is not modified by exposure to stutterers, familial relationships, and/or educational background, further research is needed to determine what, if any factor, can modify the pervasive negative stereotype.     

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/.     

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.     

Duration of subsegments within the intervocalic interval in stutterers and nonstutterers

Intervocalic intervals (IVI) from the contextual fluent speech of 14 stutterers and controls were examined at one-quarter speed on simultaneously prepared spectrograms and intensity x time displays. Seven subsegments within the IVI were identified and their durations compared between the two groups. Stutterers were slower than controls in transitional subsegments, corresponding to movements of the tongue and larynx, but not in steady-state subsegments. The results are interpreted as suggesting that stutterers are not able to move their laryngeal and supralaryngeal structures as quickly as nonstutterers.     

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.     

Temporal characteristics in the fluent speech of child stutterers and nonstutterers

Past research reveals that adult stutterers often possess aberrant speech-timing abilities. As yet, only Healey and Adams (1981) have investigated these abilities in child stutterers. The present study attempted to assess the speech-timing skills of child stutterers and normal-speaking children while performing both simple and complex speech. Each subject was required to participate in two tasks: a sentence repetition task for simple speech and a story-retelling task for complex speech. Results supported those found by Healey and Adams, indicating that child stutterers have speech-timing abilities similar to normal-speaking children in simple speech tasks. The complex task, however, revealed that stutterers exhibited more frequent and longer interword pauses than nonstutterers. Two hypotheses generated from past research are offered to explain these differences. A third untested theory is also presented.     

Manual reaction time to linguistic stimuli in child stutterers and nonstutterers

Ten stuttering and ten nonstuttering children, ages 4–8 yr, served as subjects for a motor reaction task to simple and complex linguistic stimuli. The subjects reacted by pressing one of four panels on a touch-sensitive board that depicted the appropriate semantic relationship in response to 30 simple and complex linguistic stimuli. There was a significant increase in the reaction time of both groups with increasing linguistic complexity. No significant differences were found in the reaction time between the two groups, nor in the interaction between group and complexity. Implications regarding linguistic processing are discussed, and an “overload” hypothesis of stuttering is dispelled. It is concluded that stutterers and nonstutterers in this study did not differ in their reaction time nor in their processing time of linguistic material.     

Clarification of the dual task dilemma: Lateralized effects for perfunctory and purposeful tasks in left- and right-handed males

The hypothesis that behavioral asymmetries with the dual task paradigm represent manual dominance was investigated with right- and left-handed males performing verbal and spatial tasks ordered by complexity. Lateralization was assessed for nonideational (perfunctory) and ideational (purposeful) components of tasks with multivariate and ANCOVA procedures. The outcomes of prerequisite tests showed the assumptions for conducting ANCOVA procedures were not satisfied with different handedness groups in the same design. However, results of the multivariate analyses suggest lateralized effects are more likely to represent the cognitive task when interference is high and may represent manual dominance when interference is low.     

The mean fundamental frequency in stutterers and nonstutterers during reading and spontaneous speech

Corresponding to the higher tension of muscles involved in speech production, a higher mean fundamental frequency should be expected in stutterers as compared to nonstutterers. It could be shown by the change scores of the mean fundamental frequency from reading to free conversation that stutterers tend to have a higher fundamental frequency during spontaneous speech.