Selected temporal, grammatical, and phonological characteristics of conversational utterances produced by children who stutter.

The purpose of this study was to assess clause, syllable, and response latency characteristics of conversational utterances produced by children who stutter. Subjects were 14 boys who stutter (M age = 52.07 months; SD = 9.02 months) and 14 boys who do not stutter (M age = 51.93 months; SD = 8.55 months). Selected aspects of speech fluency, clause and syllable structure, and response latency were analyzed in utterances collected from each subject as he spoke with his mother during a 30-minute conversation. Results indicated that stuttered utterances of children who stutter contained significantly more clausal constituents than their length-matched fluent utterances. There was, however, no significant difference in syllable structure of the length-matched utterances, and neither stuttering frequency nor duration was significantly associated with syllable structure measures. Further, there was no significant difference in response latency of non-length-matched stuttered and fluent utterances. Findings are taken to suggest that changes in the number of clausal constituents that must be constructed, stored, or coordinated within an utterance may influence the likelihood of speech errors and, hence speech disfluencies within that utterance.

Treatment efficacy: stuttering.

The purpose of this article is to review the state of the art regarding treatment efficacy for stuttering in children, teenagers, and adults. Available evidence makes it apparent that individuals who stutter benefit from the services of speech-language pathologists, but it is also apparent that determining the outcome of stuttering treatment is neither easy nor simple. Whereas considerable research has documented the positive influence of treatment on stuttering frequency and behavior, far less attention has been paid to the effects of treatment on the daily life activities of people who stutter and their families. Although it seems reasonable to assume that ameliorating the disability of stuttering lessens the handicap of stuttering, considerably more evidence is needed to confirm this assumption. Despite such concerns, it also seems reasonable to suggest that the outcomes of treatment for many people who stutter are positive and should become increasingly so with advances in applied as well as basic research.

Stuttering and phonological disorders in children: examination of the Covert Repair Hypothesis.

The purpose of this study was to evaluate whether the Covert Repair Hypothesis (CRH; Postma & Kolk, 1993), a theory designed to account for the occurrence of speech disfluencies in adults who stutter, can also account for selected speech characteristics of children who stutter and demonstrate disordered phonology. Subjects were 9 boys who stutter and exhibit normal phonology (S + NP; mean age = 61.33 months; SD = 10.16 months) and 9 boys who stutter and exhibit disordered phonology (S + DP; mean age = 59.11 months; SD = 9.37 months). Selected aspects of each child's speech fluency and phonology were analyzed on the basis of an audio/videotaped picture-naming task and a 30-min conversational interaction with his mother. Results indicated that S + NP and S + DP children are generally comparable in terms of their basic speech disfluency, nonsystematic speech error, and self-repair behaviors. CRH predictions that utterances produced with faster articulatory speaking rates or shorter response time latencies are more likely to contain speech errors or speech disfluencies were not supported. CRH predictions regarding the co-occurrence of speech disfluencies and speech errors were supported for nonsystematic ("slip-of-the-tongue"), but not for systematic (phonological process/rule-bases), speech errors. Furthermore, neither S + NP nor S + DP subjects repaired their systematic speech errors during conversational speech, suggesting that systematic deviations from adult forms may not represent true "errors, " at least for some children exhibiting phonological processes. Findings suggest that speech disfluencies may not represent by-products of self-repairs of systematic speech errors produced during conversational speech, but that self-repairs of nonsystematic speech errors may be related to children's production of speech disfluencies.

Disfluency clusters of children who stutter: relation of stutterings to self-repairs.

The purpose of this study was to account for the frequency, type, and possible origins of speech disfluency clusters in the spontaneous speech of 3- to 6-year-old children, 30 who stutter and 30 who do not stutter. On the basis of the Covert Repair Hypothesis (Postma & Kolk, 1993), which suggests that stutterings are the by-products of self-repairs or self-corrections of speech errors, three hypotheses were tested in attempts to account for the frequency and location of stutterings within speech disfluency clusters. Sequences of various types of speech disfluencies in utterances containing disfluency clusters were collected from audio/videotaped conversations between each of these 60 children and their mothers. Three types of speech disfluencies--overt self-repairs, covert self-repairs, and within-word disfluencies ("stutterings")--and the disfluency clusters they comprised, were identified and analyzed frame-by-frame. Results indicated that children who stutter produced significantly more stuttering-stuttering clusters (e.g., "I-I-I w-w-want ..." or "w-w-waaaant") and that, although children who do not stutter occasionally produced stutterings, they never produced stuttering-stuttering clusters. Furthermore, children who stutter produced significantly more stuttering-repair clusters, whereas children who do not stutter produced significantly more repair-repair clusters. Within the disfluency clusters of children who do not stutter, stutterings were more likely to follow an overt self-repair produced at a relatively fast speaking rate (6.6 sylls/sec). Findings are taken to suggest that stuttering-stuttering clusters may help differentiate between children who do and do not stutter, and that speech errors, self-repairs, and speech disfluencies influence one another within and between adjacent sounds, syllables, and words in what appears to be a nonhappenstance and theoretically important fashion.

F2 transitions during sound/syllable repetitions of children who stutter and predictions of stuttering chronicity.

The purpose of the present study was to examine the relationships between second formant (F2) transitions during the sound/syllable repetitions (SSRs) of young children who stutter and their predicted chronicity of stuttering. Subjects were 13 youngsters who stutter, who were divided into two groups based on their predicted chronicity of stuttering as measured by the Stuttering Prediction Instrument (SPI; Riley, 1984): a high-risk group, consisting of 7 boys (mean age = 50.6 months), and a low-risk group, consisting of 5 boys and 1 girl (mean age = 48.5 months). Each child was audio/videotape-recorded during a 30-minute conversational interaction with his or her mother. Ten SSRs per child were acoustically analyzed to identify differences in F2 transitions between the repeated (stuttered) and fluent (nonstuttered) portions of the words. Present findings are consistent with those of Stromsta (1965, 1986), who reported that children who stutter produce F2 transitions during stuttering that are nonmeasurable or missing or that differ in direction of movement from fluent transitions. However, there were no significant between-group differences in the frequency of occurrence of these "abnormal" F2 transitions, findings that are apparently inconsistent with Stromsta's results. The remaining measurable F2 transitions showed no significant between-group differences in the mean differences between stuttered and fluent F2 transitions for onset and offset frequencies, transition extents, and transition rates. Within both groups, significant positive correlations were found between stuttered and fluent F2 transitions for all acoustic measures except for transition durations, which were not significantly correlated for either high-risk or low-risk subjects. Within the low-risk group, stuttered F2 transitions were typically shorter than fluent transitions. Findings were taken to suggest that some elements of sound or segment prolongation may be present within the SSRs of children who stutter and who are considered to be at high risk for continuing to stutter, indicating that further study of selected aspects of F2 transitions during stuttering may provide useful clinical information for predicting the likelihood that a child will continue to stutter.

Coexistence of stuttering and disordered phonology in young children.

The purpose of the present study was to assess differences in stuttering, phonological, and diadochokinetic behaviors in young children who exhibit both stuttering and disordered phonology and children who exhibit only one of the disorders. Subjects were 21 male children (aged 4 to 6 years), representing three groups of seven children each: (a) stuttering and normal phonological abilities (S+NP), (b) stuttering and disordered phonology (S+DP), and (c) normal fluency and disordered phonology (NF+DP). Stuttering behavior was assessed during a 30-minute conversational speech task; phonological behavior was assessed during a 162 item picture-naming task; and diadochokinetic abilities were assessed during bi- and multisyllable productions. Results indicated that the S+DP group produced significantly more sound prolongations and significantly fewer iterations per whole-word repetition than the S+NP group. However, there were no differences between the two groups in other stuttering indices. Moreover, no differences were noted between the S+DP and NF+DP groups in phonological behavior. Diadochokinetic rates did not differ among the three groups. The possibility of two types of stuttering, one occurring with and one without disordered phonology, is discussed.

Speaking rates, response time latencies, and interrupting behaviors of young stutterers, nonstutterers, and their mothers.

The purpose of this study was to investigate the speaking rates, interrupting behaviors, and response time latencies (RTL) produced by stuttering and nonstuttering children and their mothers, and the relationship these three paralinguistic behaviors have to children's speech disfluencies. Subjects were 13 boys who stutter (mean age = 4:0) and their mothers and 13 nonstuttering boys (mean age = 4:0) and their mothers. No significant differences were found between the two groups of children or between the two groups of mothers for any of the three paralinguistic behaviors with the exception that the mothers of nonstuttering children exhibited significantly (p < 0.01) faster rates of speech than either group of children. A strong positive correlation (r = .84) was found between stuttering children's scores on the Stuttering Severity Instrument (Riley, 1980) and the durations of the overlapping portions of their mothers' interruptions (i.e., their simultalk). Findings of this study are taken to support a facilitative demands-capacities model of conversational interaction in which mothers adjust the demands of their speaking models in response to their children's demonstrated capacities for fluent speech production.

Young stutterers' nonspeech behaviors during stuttering.

The purpose of this study was to assess the nonspeech behaviors associated with young stutterers' stuttering and normally fluent children's comparable fluent utterances. Subjects were 28 boys and 2 girls who stutter (mean age = 54 months) and 28 boys and 2 girls who do not stutter (mean age = 54 months). Each child and his or her mother were audio-video recorded during a loosely structured, 30-min conversation. Sixty-six different nonspeech behaviors associated with 10 randomly selected stutterings per stutterer and 10 comparable fluent utterances per normally fluent child were assessed by means of frame-by-frame analysis of the audio-video recordings. Results indicate that (a) young stutterers produce significantly more nonspeech behaviors during stuttered words than do normally fluent children during comparable fluent words, (b) young stutters produce significantly more head turns left, blinks, and upper lip raising during stuttered words than do normally fluent children during comparable fluent words, and (c) talker group membership could be significantly determined on the basis of certain types of nonspeech behaviors despite considerable overlap in frequency and type of nonspeech behavior between the two talker groups. Findings suggest that children can be classified as stutterers on the basis of their nonspeech behaviors and that these behaviors may reflect a variety of cognitive, emotional, linguistic, and physical events associated with childhood stuttering.

Comorbidity of stuttering and disordered phonology in young children.

Young stutterers frequently exhibit concomitant speech and/or language disorders. The co-occurrence of these disorders is, however, not yet well understood. The purpose of this paper is to introduce the notion of "comorbidity" as it relates to the field of speech-language pathology: specifically, to discuss comorbidity (coexistence) of stuttering and disordered phonology in young children. Literature on concomitant speech and language disorders in young stutterers is reviewed, with special reference to the prevalence of articulatory/phonological disorders in young stutterers. Future research on the coexistence of two speech and language disorders is encouraged, as well as the consideration of diagnostic treatment and prognostic implications for children who exhibit both stuttering and disordered phonology as opposed to children who exhibit each disorder in isolation.

Judgments of disfluency by mothers of stuttering and normally fluent children.

The purpose of this study was to examine the relation between selected aspects of speech disfluency and perceptual judgments of these events by mothers of young stutterers and mothers of age- and sex-matched normally fluent children. Each mother independently listened to and judged as either "stuttered" or "not stuttered" recorded examples of a young stutterer's imitated productions of: (a) five different types of speech disfluency, (b) sound prolongations, and (c) sound/syllable repetitions of five different durations each, along with a comparable number of fluent utterances. Results indicated that although some between-group differences in judgments were observed, both groups most frequently judged sound/syllable repetitions to be stuttered, followed by whole-word repetitions and broken words. Fluent utterances, interjections, and sound prolongations were most frequently judged to be not stuttered by all mothers. Both groups judged sound prolongations averaging 258 ms in duration to be stuttered an average of 25% of the time, increasing to 68% for sound prolongations averaging 1254 ms; however, both groups of mothers judged sound/syllable repetitions of two or more iterations to be stuttered an average of 93% of the time. Findings suggest that there are not appreciable differences between mothers of stuttering and normally fluent children regarding their perceptual judgments of speech disfluencies, but each group might more frequently judge as stuttered those types of speech disfluencies characteristic of their own children's speech.

Selected temporal aspects of coordination during fluent speech of young stutterers.

The purpose of this study was to compare the onsets, offsets, and durations of respiratory, articulatory, and laryngeal behaviors associated with the perceptually fluent speech of young stutterers (n = 8) to those of their normally fluent peers (n = 8). Simultaneous recordings of the targeted behaviors were made using noninvasive, minimally intrusive instrumentation. Specific temporal parameters of coordination--onsets, offsets, and durations of muscle activity and structural movement--were assessed within a particular component of the speech production system (e.g., onset of lower lip closing relative to lower lip opening muscle activity) as well as between different components (e.g., onset of rib cage deflation relative to onset of vocal fold contact for voicing). Results indicated that there were neither statistically significant nor apparent differences between the perceptually fluent speech of young stutterers and that of their normally fluent peers in terms of selected temporal characteristics of coordination. Findings suggest that the molar temporal characteristics of coordination for young stutterers' fluent speech production(s) are not appreciably different from those of their normally fluent peers and further, any temporal characteristics of stutterers' fluent speech that do differ from normal are probably brief, as well as subtle, in nature.

Subgrouping young stutterers: preliminary behavioral observations.

The purpose of this investigation was to identify speech and nonspeech behaviors associated with stuttering of young persons and to use these behaviors in attempts to discern and describe subgroups of these individuals. Forty-three young stutterers (10 girls and 33 boys) produced stutterings and associated behaviors during conversations that were video/audio recorded. Fourteen associated speech and nonspeech behaviors and speech disfluency types were identified and quantified for 10 stutterings from each of the 43 subjects. The 14 associated behaviors and speech disfluency types were further reduced to form three related indices: (a) Sound Prolongation Index, (b) Nonspeech Behavior Index, and (c) Behavioral Variety Index. Results indicated that five subgroups of young stutterers could be identified and described on the basis of these youngsters' number and variety of speech and nonspeech behaviors associated with their stuttering. Findings are taken to suggest that these speech and nonspeech behavioral differences reflect differences in young stutterers' reactions and adjustments to their problem.

Electroglottographic observations of young stutterers' fluency.

The purpose of this study was to compare the laryngeal behavior associated with the perceptually fluent speech of young stutterers (n = 8) to that of their normally fluent peers (n = 8). Laryngeal behavior during fluent productions of the initial and final consonants and medial vowels in each of the words Pete, bake, face, and veal was observed by means of an electroglottograph (EGG). The recorded EGG signal was electrically processed to obtain a measure of vocal fold abduction from the "open quotient" (glottal open time divided by glottal period) during consonant-vowel (CV) and vowel-consonant (VC) transitions, as well as during the central portion of the vowel. In each case, a Typical pattern for the abduction measure that was consistent with the underlying production mechanism for the sound sequence was found for the normally fluent subjects. The normally fluent children exhibited significantly more Typical patterns during the CV/CV transitions than did the stuttering youngsters, with 72% of the total transition samples from normally fluent youngsters being Typical versus 42% for the young stutterers. Though some Atypical patterns for the vowels were noted, most of the normally fluent (94%) and stuttering (84%) youngsters' total vowel samples were Typical. These findings suggest that some young stutterers tend to have difficulty stabilizing and controlling laryngeal gestures even during speech judged fluent by trained listeners, particularly at those points in the utterance where these youngsters must move between sound segments.

Laryngeal behavior during stuttering: a further study.

The purpose of this study was to provide detailed, objective descriptions of stutterers' laryngeal behavior during instances of stuttering within conversational speech. Subjects were 11 adult stutterers who produced stutterings (sound prolongations and sound/syllable repetitions) while their laryngeal behaviors were observed by means of a flexible fiber-optic nasolaryngoscope (fiberscope). Laryngeal behaviors during 86 of the 11 stutterers' stutterings were categorized as adducted, intermediate, or abducted. Results indicate that during sound prolongations the vocal folds were more likely to be adducted and less variable in their movement than during sound/syllable repetitions. Results further indicated that the voicing characteristics of the stuttered sound (voiceless vs. voiced) and the type of stuttering (sound prolongation vs. sound/syllable repetition) interactively influenced laryngeal behavior. It is hypothesized that a complex interaction among the laryngeal, articulatory, and respiratory systems contribute to the occurrence of the inappropriate abductory and/or adductory laryngeal behavior which characterizes prolonged or repeated (stuttered) speech segments.

Deaf speakers' laryngeal behavior.

The purpose of this study was to compare deaf speakers' (n = 4) laryngeal behavior during voiced and voiceless consonant productions to that of normal hearing subjects (n = 4). Laryngeal behavior during these two speaker groups' productions of six word-initial stop plosives (/b d g p t k/) and fricatives (/v z delta f s pheta/) was visually observed by means of a flexible fiberoptic nasolaryngoscope (fiberscope). The visualizations and their acoustic correlates were audiovisually recorded. The audiovisual recordings were analyzed by means of both frame-by-frame categorical judgments of laryngeal behavior and broad phonetic transcriptions of the accuracy/inaccuracy of consonantal voicing. Results indicated that deaf speakers' laryngeal behavior during production of those consonants perceived as accurately voiced was comparable to that of normal speakers, whereas deaf speakers' laryngeal behavior during production of consonants perceived as inaccurately voiced generally differed in various ways from normal. Findings seem to suggest that some aspects of deaf speakers' atypical laryngeal behavior associated with inaccurately voiced consonants may be due to an aberrant linguistic system while other aspects may be due to inadequate laryngeal motor control.

Youngsters who stutter: diagnosis, parent counseling, and referral.

The purpose of this paper is to present clinical considerations regarding the speaking behavior, nature, and environment of young children who stutter. The speech of these children contains more within-word speech disfluencies (sound/syllable repetitions, sound prolongations, and within-word pauses) than that of their normally fluent peers. Although the physical, mental, social, psychological, and communicative nature of these children is not grossly different than that of unaffected children, some youngsters who stutter do exhibit subtle delays or deviancies in speech sound articulation, expressive language, and fine/gross motor coordination skills. The young stutterer's environment is as variable as that of the average child. Careful observation reveals subtle, and some not so subtle, parental attitudes which seem to foster the child's belief that speaking is a difficult task, requiring mental and physical effort, and that it must be produced precisely, quickly, and maturely. Information is provided to clinicians working with children between 2 and 6 years of age (the time period when stuttering usually begins) which should assist in objective identification of childhood stuttering, recognition of those symptoms which most strongly suggest referral, as well as an understanding of basic "facts" about this most complex of communication disorders.

Voice onset time, frication, and aspiration during stutterers' fluent speech.

The purpose of this study was to investigate voice onset time (VOT) and durations of frication and aspiration in stutterers' fluent speech. Broadband wound spectrograms were used to measure five adult stutterers' and five adult normally fluent controls' VOT, frication and aspiration durations during fluent productions of 18 word-initial sounds or sound clusters. Results indicate that stutterers' mean VOT for six of the 18 sounds/sound clusters (/p b br pr tw bl/) was significantly different from that of normally fluent speakers. VOT values for four of these 18 sounds/sound clusters (/b bl p tw/) could, to a moderate degree, be predicted from knowledge of whether a subject is a stutterer or a normally fluent speaker. With one exception, aspiration duration for /tw/, stutterers were not significantly different from normally fluent speakers in terms of frication and aspiration durations. These results suggest that stutterers' VOT during fluency is within normal limits and as such is of small assitance in distinguishing between stutterers and normally fluent speakers.

Effects of noise and rhythmic stimulation on the speech of stutterers.

This study was designed to investigate the effects of noise and rhythmic stimulation on stutterers' vocal fundamental frequency, vowel duration, and vocal level, and the relation these variables have to one another and to stuttering during noise and rhythmic stimulation. Measurements of speech variables were obtained from audio and graphic-level recordings and from narrow- and broad-band spectrograms. Results indicated that stuttering was significantly reduced during noise and rhythmic stimulation with the reduction during rhythmic stimulation being significantly greater than the reduction during noise. Decreases in stuttering were correlated with increases in vowel duration during both conditions for seven of nine subjects. We interpret our findings to suggest that temporal changes in speech production are related to the decrease in stuttering that occurs during noise and rhythmic stimulation.

Laryngeal behavior during stuttering.

Laryngeal behavior associated with 101 stutterings (part-work repetitions, sound prolongations, and broken words) produced by a group of 10 stutterers was observed by means of a flexible fiberoptic naso-laryngoscope. Results indicated that 60% of part-word repetitions were different from fluent productions of the same speech segment in terms of laryngeal behavior, and 72% of sound prolongations were similar to fluent productions of the same speech segment. Findings indicate that there are differences in laryngeal behavior among the various types of stutterings.