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.     

Factors affecting judgments of fluency: II. Word repetitions

Six speech samples containing varying amounts of whole-word repetitions were tape-recorded and presented to 36 male and 36 female listeners. For each sample, listeners were asked to make judgments of fluent, disfluent, and stuttered speech, and to answer the question, “Would you recommend speech therapy?” Results showed that samples containing 5% or more word repetitions were not judged fluent speech by a majority of listeners. Judgments of disfluent and stuttered speech were nearly equal for speech samples containing word repetitions from 5% to 15%. At 20%, however, the judgments of stuttered speech were found to be more likely than judgments of disfluent speech. A majority of listeners recommended clinical services for speech samples containing 5% or more word repetitions. Generally, the results indicated that (1) the presence of whole-word repetitions is not normal regardless of frequency, (2) fluent speech may not contain 5% or more word repetitions, and (3) with 20% word repetitions the judgments of stuttering may be more likely than judgments of disfluency.     

Factors affecting judgments of fluency: I. interjections

Six speech samples containing varying amounts of schwa interjections were tape-recorded and presented to 36 male and 36 female listeners. For each sample, listeners were asked to make judgments of fluent, disfluent, and stuttered speech, and to answer the question “Would you recommend speech therapy?” Results indicated that speech samples containing 5% or more interjections evoked a judgment of disfluent speech by a majority of listeners. The sample containing 20% interjections, however, was found to evoke judgments of disfluent and stuttered speech about equally. Varying numbers of listeners recommended clinical services for disfluent speech. In general, the results indicated that (1) the presence of interjections in connected speech is not normal regardless of frequency, (2) fluent speech may not contain interjections in excess of 5%, and (3) with 20% interjections in speech, the distinction between disfluency and stuttering may be blurred.     

Reinforcing fluency in stutterers: An experimental study

Subject-specific periods of fluent reading responses of three adult stutterers were positively reinforced with the presentation of a dime. Subjects were run individually through a sequence of two base rate, two experimental, and two extinction sessions, each session lasting 45 min. Periods of fluent reading responses increased during the experimental condition for each of the three subjects. When the reinforcer was withdrawn during the extinction condition, the frequency of fluent periods showed a decrease. Concomitantly, disfluencies decreased during the experimental condition and they increased during the extinction condition. The clinical implications of fluency manipulation as against disfluency manipulation are discussed.     

Some relationships between adaptation and electromyographic activity at laryngeal and masseter sites in stutterers

Cumulative integrated electromyographic (EMG) activity was recorded from laryngeal and masseter sites from ten stutterers during a five trial oral adaptation sequence. Results showed more activity at the laryngeal site than the masseter site. While significant reductions in EMG activity were not found, patterns were shown to be related to the subjects' dysfluency patterns over trials. Results were interpreted as suggesting that reduced muscle activity and adaptation (when they occur) are artifacts of other behavioral modifications resulting from overt motor practice.     

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.     

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.     

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.     

Dominance as a function of cue similarity: A test of the intrinsic cue dominance model

A nonselective model postulating intrinsic cue dominance was tested in simultaneous discrimination tasks involving reversal on one dimension. In this procedure two dimensions are relevant throughout training; however, following initial discrimination training the reward contingency is reversed for one dimension but maintained for the other. Cue dominance was assessed following acquisition of reversal by the use of opposed-cues test trials, and was defined as a greater number of choices of the test compound containing the positive cue of the reversed dimension than of the test compound containing the positive cue of the maintained dimension. In Experiment I, brightness cues dominated orientation cues. In Experiment II, which employed two different sets of relevant cues, more disparate brightness cues dominated the orientation cues for one set and orientation cues dominated less disparate brightness cues for the other. From this, it was concluded that dominance is a function of relative cue similarity.     

A feature analysis of stuttered phonemes

Stuttered and nonstuttered phonemes of 20 adult males were analyzed for distinctive feature patterns using the Chomsky-Halle system. The features (+ consonantal), (- voice), (+ continuant), and (- strident) occured significantly more often in stuttering than in nonstuttering instances. Results suggest that adult stuttering is most likely to occur when the primary sites of tension and discoordination are lingual and laryngeal and when the speaker must shift from (- voice) to (+ voice).     

Stutterers' voice initiation times during conditions of novel stimulation

The present experiment examined stutterers' voice initiation times (VITs) during conditions of novel stimulation. The experimenters were interested in determining how VITs varied as a function of pacing and masking. Stutterers were examined in control, pacing, and masking conditions. The results indicated that: (1) stutterers significantly improved their VITs in the pacing condition as compared with the control condition (p = 0.005), (2) stutterers had significantly faster VITs in the pacing condition as compared with the masking condition (p = 0.005), and (3) stutterers improved VITs in the masking condition as compared with the control condition (p = 0.075). These results are discussed in terms of the facilatory nature of novel stimulation in modifying speech-system functioning.     

Click location in sentences: A test of the linguistic competence of seven-year-old fluent and disfluent males

Ten fluent and ten disfluent 7-yr-old males were presented simple and complex fully grammatical, anomalous and scrambled sentences. A click (35-msec 1-kHz tone burst) had been superimposed within three positions to the right or left of the major syntactic boundary in each sentence. The subjects heard the sentence, repeated the sentence, and marked on a preprinted version of the sentence where they heard the click. It was expected that children with greater language facility would more probably locate the click veridically. By the same reasoning, less complex syntactic structures should be expected to influence click placement less than more complex utterances. The following results were obtained: (a) the disfluent group gave a greater number of correct responses than the fluent group; (b) more correct responses were observed for simple sentences than for complex sentences for both groups; and (c) fewer correct responses were observed for both simple and complex grammatical sentences than for anomalous and scrambled sentence types.     

Teacher attitudes toward stuttering

Attitudes of 100 elementary school teachers toward stuttering were studied using the Teacher Attitudes Toward Stuttering (TATS) Inventory. Teacher attitudes, as indicated by TATS Inventory scores, were compared with teacher knowledge of stuttering, age of teacher, number of years teaching experience, educational level, and whether the teacher had personal experience with a stutterer. Results indicated that significant positive correlations existed between teacher attitudes toward and knowledge of stuttering. Significant negative correlations were demonstrated between teacher attitudes/knowledge of stuttering and the presence of a stuttering child in the classroom. The applicability of the TATS Inventory as a clinical instrument in its current form and the research needed to enhance its flexibility are discussed.     

Transfer between downshift in reward magnitude and continuous delay of reward

Two separate experiments were conducted to investigate transfer of persistence between delay and a downshift in reward magnitude. In the first experiment, experimental rats were initially downshifted in reward magnitude and later tested for persistence to continuous delay of large reward. It was found that these rats were more persistent to the effects of delay than control rats which did not receive prior experience with a downshift in reward magnitude. In the second experiment, experimental rats were first trained to receive large reward under delayed conditions and then tested for persistence to a downshift in reward magnitude. Compared to control rats which received no prior experience with delay, the experimental rats showed a significantly smaller negative contrast effect. The results were interpreted as supporting Amsel's theory of persistence as well as Capaldi's recent interpretation of contrast effects.     

The identification of stuttering: Can you look and tell

This investigation focussed on how observers identify stutterers. It was found that stutterers are identified most correctly under visual circumstances as compared to auditory and combined auditory-visual conditions. Therefore, the reduction of stuttering should include removal of noticeable, interfering, and unnecessary nonverbal behaviors, particularly mouth and nostril movements.     

Stammering: A stress index in Caribbean classrooms

Speech communities in the British West Indies typically include two major dialect or code distinctions: (1) a standard variety of British West Indian English, and (2) a local variety of English-based dialect. Each dialect or code is intimately linked with political, social, racial, and economic class distinctions. In bicultural settings, characterized by diglossia, there are special situations in which loyalty to one's mother tongue conflicts with social, economic, and political expediency. “No win” speech events or contests, the product of conflicting sociocultural values, become salient features of this particular kind of bicultural setting. A comparatively high incidence of teacher-reported stammering found in two British West Indian speech communities supports this notion and suggests that stress, originating at a sociocultural level, is symbolically expressed through attitudes toward and usages of language. These results further suggest that the classroom, now a “battleground”, will suffer as an effective teaching/learning environment. This paper presents arguments for the teaching of Standard English as a second language with an emphasis on giving regional dialects appropriate and long overdue recognition.     

Dichotic speech perception: A comparison between stuttering and nonstuttering children

A stop consonant-vowel dichotic listening task was administered to 90 right- handed boys, 30 in each age group of 5, 7, and 9 yr. Half in each group were stutterers, half nonstutterers. Two and a half times as many stutterers as nonstutterers were found to display either a left-ear advantage (LEA) or no ear advantage (NEA). This finding suggested a greater tendency on the part of stutterers, as opposed to nonstutterers, for reversed or bilateral representation of the auditory speech areas of the brain. In addition, both stutterers and nonstutterers displayed significant developmental increases in the number of times they were able to identify both dichotic speech stimuli, thereby supporting the hypothesis of an age-related increase in children's total information processing capacity. The results are discussed in terms of the differences between stutterers and nonstutterers with respect to the issues of motor representation, cognitive modes, and higher-order linguistic processes.