Hemispheric alpha asymmetries during an electromyographic biofeedback procedure for stuttering: A single-subject experimental design

A single-subject “double-reversal” experimental design was used to investigate the use of electromyographic (EMG) biofeedback on the dysfluent behaviors of a right-handed male stutterer. A systematic decrease in EMG amplitude accompanied a progressive approximation of increased verbal complexity resulting in increased fluent behavior. Electroencephalographic (EEG) alpha data (8–12 Hz) gathered during baseline and pre- and post- treatment sessions appeared to co-vary with changes in fluency with right hemispheric suppression associated with greater dysfluencies and left hemispheric alpha suppression with decreased dysfluencies. The results are discussed relative to stutterer's adoption of differing behavioral production strategies for fluent speech that are associated with hemispheric information processing strategies.     

Hemispheric alpha asymmetries of stuttering males and nonstuttering males and females for words of high and low imagery

Alpha hemispheric asymmetries of nonstuttering males, nonstuttering females, and stuttering males were explored with electroencephalographic procedures during exposure to two lists of one-syllable words which the subjects were required to recall following presentation. One word list contained low-imagery words while the other contained high-imagery words. Stuttering males were found to have significantly less alpha in their right hemispheres, suggesting right hemispheric processing strategies. This finding was interpreted as supporting the “segmentation dysfunction” explanation of stuttering suggested by Moore and Haynes (1979b). Nonstuttering males showed less left than right alpha while nonstuttering females revealed no difference between their right and left hemispheres. Differences between nonstuttering males and females are discussed as being task and stimuli dependent relative to the segmental/nonsegmental nature of both task and stimuli. Differential hemispheric asymmetries for words of high or low-imagery were not observed.     

A study of alpha hemispheric asymmetries for verbal and nonverbal stimuli in males and females

The alpha hemispheric asymmetries of males and females were examined with electroencephalographic (EEG) techniques during exposure to connected speech and nonlinguistic stimuli. The subject selection controlled for familial handedness and each subject was administered the Block Design and Vocabulary Subtests of the WAIS as a general measure of “visual-spatial” and “verbal” ability. The results showed that there was less alpha in the right hemisphere for nonverbal tasks and less alpha in the left hemisphere for verbal tasks. The females showed significantly more “lateralization” during the tasks as compared to the males. The results are discussed in terms of processing differences and the possible effects of subject variables, stimulus mode, stimulus presentation, and task requirements on neurolinguistic research results.     

Sex task and processing strategy effects in hemispheric alpha asymmetries for the recall and recognition of arousal words: results from perceptual and motor tasks in males and females

Hemispheric alpha asymmetries of males and females were observed during perceptual and motor tasks requiring recall and recognition of words controlled for level of arousal (positive, negative, and neutral). Verbal reports of individual processing strategy were collected and analyzed relative to hemispheric alpha ratios. Results showed greater alpha suppression in the left relative to right hemisphere for recall as compared to recognition tasks and for word presentation when contrasted with motor conditions. High positive correlations were found between narrative report of processing strategy and hemispheric alpha data. A separate analysis revealed that seven subjects identified as highly analytic processors showed greater alpha suppression in the left relative to right hemisphere across tasks, conditions, and stimuli than did seven highly visual processors who, in contrast, demonstrated greater right hemispheric alpha suppression. Task difficulty and individual differences in processing style that modify cerebral laterality effects are discussed.     

Hemispheric alpha asymmetries of words with positive, negative, and neutral arousal values preceding tasks of recall and recognition: Electrophysiological and behavioral results from stuttering males and nonstuttering males and females

Hemispheric alpha asymmetries were obtained for stuttering males and nonstuttering males and females for words of positive, negative, and neutral arousal values. Electroencephalographic data were gathered during the presentations of stimulus words and during the actual nonoral recall and recognition of the stimulus items. Stuttering males demonstrated right-hemispheric alpha suppression across stimulus words and tasks as contrasted with left-hemispheric alpha suppression for the nonstuttering males and females. Stuttering males were also shown to recall and recognize fewer words than the nonstuttering subjects across arousal categories. Subjects were also administered a modified version of A. Paivio's (1971, In B. Randhawa & W. Coffman, Eds., Visual thinking, learning, and communication, New York: Academic Press) Individual Differences Questionnaire (IDQ). Results showed our stuttering males to have obtained lower scores on the verbal and imagery questions of the IDQ as compared to the nonstuttering groups. Hemispheric alpha asymmetry results and memory performance from the stuttering males are discussed relative to nonsegmental, right-hemispheric processing strategies.     

The effects of visual feedback on hemispheric alpha asymmetries and reported processing strategies: a single-subject experimental design

A double reversal single-subject experimental design was used to study the effects of visual feedback on the hemispheric alpha asymmetries of a male subject during a linguistic task. Results indicated that the subject demonstrated flexibility in hemispheric alpha and corresponding processing strategies employed when an alpha biofeedback procedure was used. These results provide further support for the notion that right and left hemispheric activation is associated with different, yet compatible, cognitive strategies and that both can be manipulated under conditions of feedback.     

Programmed stuttering therapy for children: Comparison of four establishment programs

Four different establishment programs (programmed traditional, delayed auditory feedback, pause, and gradual increase in length and complexity of utterance) for improving the fluency of school-age children who stutter were compared. The programs were carried out by eight public school clinicians with 16 children (eight elementary and eight junior-senior high school) in their respective schools. All four programs produced important improvement in the speech fluency of the 16 children. All the children demonstrated transfer of fluency to extratraining settings. The delayed auditory feedback program required the least therapy hours, but it was difficult for the clinicians to operate correctly. The gradual increase in length and complexity of utterance programs produced the best overall results. The transfer and maintenance programs provided for additional generalization and permanency of fluency. Follow-up revealed that the children continued their increased level of fluency.     

The use of a portable delayed auditory feedback unit in stuttering therapy

A portable on-the-body delayed auditory feedback was used in the establishment and transfer modes of fluent speech in a stutterer while he was on the Monterey Fluency Program. The performance of the client was compared with a “standard” population of stutterers. The portable DAF was comparable to the larger DAF in establishment and superior in transfer with minimal behavioral and technical problems. Use and potential value of the portable DAF in transfer and maintenance phases of therapy are discussed.     

Cumulative integrated electromyographic activity of selected speech-related muscle groups of nonstutterers during massed oral readings

The electromyographic (EMG) integrated amplitude of masseter and laryngeal muscle groups were analyzed during five massed oral readings of 16 nonstuttering adult subjects. Reduction in dysfluencies were observed over the five trials as was a reduction in reading time across trials. Significant decreases in EMG activity across trials were found for the laryngeal, but not the masseter, EMG activity. This suggests that changes in vocal behavior thought to accompany adaptation are reflected in decreases in EMG activity of select speech-related muscle groups.     

The effects of communication,resource feedback,and identifiability on behavior in a simulated commons

This study examined the effects of communication, feedback, and identifiability on behavior in a simulated commons. To do this, 64 mixed-sex groups of four introductory psychology students participated in a commons dilemma simulation for 50 trials or until the group exhausted the commons pool. Half of the groups played under a free communication condition, while the other half were prohibited from communicating. Half of the groups in both communication conditions received visual feedback about the amount of the commons' resource (money) which remained after each trial while the other half received no feedback. Finally, half of the groups in each of these four conditions were made highly identifiable by the use of the name tags and feedback about the choices of each player. The remaining groups were assigned to a low identifiability condition in which no name tags were used, no feedback given and group members were separated by wooden dividers to prevent visual contact. Results showed that groups having the opportunity for resource feedback or for communication achieved greater total money harvests and maintained the commons for a greater number of trials than groups having neither. As expected, the largest totals and longest commons maintenance were achieved by groups having both. Identifiability had no influence on the length of commons maintenance except when there was neither resource feedback nor communication opportunities. When both were unavailable, groups in the high identifiability condition harvested more money and maintained the commons longer.     

Antecedents of fluent and dysfluent oral reading: A descriptive analysis

Utilizing the method of repeated observations of a single subject, 18 oral reading samples were obtained from a fluent male child. Observations were made when the child was 5.6 to 6.1 yr of age. The reading material contained varying amounts of words neither understood nor produced by the child. Taped samples were analyzed for antecedents and consequences of fluent and dysfluent events, and extraneous verbal and nonverbal stimulus-response sequences. The analysis revealed the presence of five antecedents of dysfluencies: (1) poor lexical control, (2) competing stimulus-response sequences, (3) intraverbal break, (4) poor prosodic control, and (5) unusually strong intraverbal control. The results also suggested that fluency may be a function of appropriate, sequential, discriminative, stimulus control, adequate intraverbal and prosodic control in the absence of overbearing intraverbal control and interfering stimulus-response sequences.     

Bilateral tachistoscopic word perception of stutterers and normal subjects

Bilateral tachistoscopic procedures were utilized to investigate the visual half-field preferences of 15 stutterers and a group of 15 normal controls. Statistical analyses indicated a right visual half-field preference for the control group. In contrast, a significant visual half-field preference was not revealed for the stuttering group. However, further analysis revealed that a significantly larger proportion of stutterers, compared to controls, demonstrated a left visual half-field preference. Results indicated reversed cerebral processing for the stuttering group as compared with the control group.     

Syntactic influences on stuttering in young child stutterers

This study examined the location and rate of stuttering in the spontaneous speech of nine young stutterers (4.0–6.6 yr) in relation to certain aspects of syntax. It was designed to answer the following questions: Is there more stuttering at clause onset (boundary) than at other points in the clause? Does the type of clause influence rate of stuttering? Is there more stuttering on complex than on simple sentences? The syntactic analysis defined 10 clause types (seven pertaining to complex sentences and three pertaining to simple sentences); clause boundaries (taking into account “filler” words occuring in such positions); and hierarchical constituent structure within sentences. Stuttering was found with significantly greater frequency at clause boundaries than at internal (nonboundary) positions of clauses. This was apparent for nine of the 10 clause types, the exception being complement clauses. The word “and” at the beginning of simple and complex sentences provoked a high rate of stuttering. The hierarchical structure within the clause did not influence the location of stuttering, and sentence complexity was not a factor in the rate of stuttering.     

Nonspecific elements in therapy with stutterers

Currently, many different strategies are employed by respected professionals working in the area of therapy for persons who stutter. This phenomenon serves as a point of departure for reflections on the nonspecific elements involved in therapy. Drawing on the literature of holistic medicine and psychotherapy these elements are identified as follows: (1) active participation of the client in the therapy process; (2) role of self-management skills; (3) influence of client's expectations regarding treatment; (4) suggestion as a factor in therapy; and (5) the therapeutic relationship.     

A component model for diagnosing and treating children who stutter

Nine components of stuttering and their distribution among 54 children who stutter are described. The components are arranged into a model that includes four neurologic components (attending disorder, auditory-processing disorder, sentence-formulation disorder, and oral-motor disorder) and five traditional components (high self-expectations, manipulative stuttering, disruptive communication environment, unrealistic parental expectations, and abnormal parental need for the child to stutter). Diagnostic and treatment usefulness of the model are discussed. Thirty-two of the children have been followed through component-based treatment and 12 mo post termination. Results indicate that treatment was successful with 27 (84%) of the 32 children. Only one child regressed during the 12 mo after treatment ended. These results suggest that treating the neurologic and traditional factors which disrupt fluency improves maintenance and carry-over.     

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/.     

Reading abilities of school-age stutterers

The reading abilities of 20 school-age stutterers and their matched normally fluent controls were assessed by means of the Woodcock Reading Mastery Tests. Results indicate that the reading abilities of school-age stutterers are not significantly different from those of school-age normals. Similarly, knowing whether a subject was classified as a stutterer or normally fluent speaker was of minimal assistance in predicting the subject's reading performance. These findings suggest that school-age stutterers' reading abilities are within normal limits. An individual stutterer, just like an individual normally fluent speaker, may exhibit “reading problems”; however, caution should be employed in extrapolating from one individual stutterer's reading performance to the reading abilities of all stutterers.     

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.     

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.