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The purpose of this study was to assess the influence of phonological priming on the speech reaction time (SRT) of children who do (CWS) and who do not (CWNS) stutter during a picture-naming task. Participants were eighteen 3-5-year-old CWS (M = 50.67 months, SD = 11.83 months), matched in age and gender with 18 CWNS (M = 49.44 months, SD = 10.22 months). The picture-naming task required each child to name, one at a time, computer-presented, white-on-black line drawings of common, age-appropriate objects "as quickly as you can" during 3 different conditions: (a) no prime, (b) related prime, and (c) unrelated prime, with naming latency (alternatively referred to as SRT; in milliseconds) as the main dependent variable. Results indicated that all children exhibited faster or shorter SRTs during the related condition compared to the no prime condition. Similarly, SRT was influenced with advancing age for all children, with 5-year-olds exhibiting faster SRTs than 3-year-olds. Furthermore, CWNS, but not CWS, demonstrated a negative correlation between articulatory mastery and SRT. Findings were taken to suggest that phonological priming is a feasible procedure for studying the speech-language planning and production of 3-5-year-old children and that preschool children who stutter, as a group, may have somewhat less well developed articulatory systems than preschool children who do not stutter. KEY WORDS: stuttering, phonology, priming, children, A considerable amount of research (e.g., Bloodstein, 1995; Cantwell & Baker, 1985; Paden & Yairi, 1996; Paden, Yairi, & Ambrose, 1999; St. Louis & Hinzman, 1988; Throneburg, Yairi, & Paden, [...]

The purpose of this study was to assess anticipatory coarticulation and second formant (F2) transition rate (FTR) of speech production in young children who stutter (CWS) and who do not stutter (CWNS). Fourteen CWS and 14 age- and gender-matched CWNS in three age groups (3-, 4-, and 5-year-olds) participated in a picture-naming task that elicited single-word utterances. The initial consonant-vowel (CV) syllables of these utterances, comprising either bilabial [b m] or alveolar [d n s z] consonants and a number of vowels [i I e [epsilon] ae u o [??] [??]], were used for acoustic analysis. To assess coarticulation and speech movement velocity, the F2 onset frequency and F2 vowel target frequency (for coarticulation) and FTR (for speech movement velocity) were computed for each CV syllable and for each participant. Based on these measures, locus equation statistics of slope, y-intercept, and standard error of estimate as well as the FTR were analyzed. Findings revealed a significant main effect for place of articulation and a significantly larger difference in FTR between the two places of articulation for CWNS than for O/VS. Findings suggest that the organization of the FTR production for place of articulation may not be as contrastive or refined in CWS as in CWNS, a subtle difficulty in the speed of speech-language production, which may contribute to the disruption of their speech fluency. KEY WORDS: stuttering, coarticulalion, children, speech acoustics, transition rate, Recent theories of stuttering suggested that people who stutter have an impaired or slower-than-normal phonological encoding ability (Perkins, Kent, & Curlee, 1991; Postma & Kolk, 1993; Wingate, 1988). Although it [...]

The goal of the present experiment was to determine if stuttering is associated with unusually high levels of activity in laryngeal muscles. Qualitative and quantitative analyses of thyroary-tenoid and cricothyroid recordings from 4 stuttering and 3 nonstuttering adults revealed the following: Compared to periods of fluent speech, intervals of disfluent speech are not typically characterized by higher levels of activity in these muscles; and when EMG levels during conversational speech are compared to maximal activation levels for these muscles (e.g., those observed during singing and the Valsalva maneuver), normally fluent adults show robust and sometimes near maximal recruitment during conversational speech. The adults who stutter had a lower operating range for these muscles during conversational speech, and their disfluencies did not produce relatively high activation levels. In summary, the present data require us to reject the claim that adults with a history of chronic stuttering routinely produce excessive levels of intrinsic laryngeal muscle activity. These results suggest that the use of botulinum toxin injections into the vocal folds to treat stuttering should be questioned. KEY WORDS: stuttering, laryngeal muscles, speech motor control, electromyography, voice

Stuttering is manifested as a disruption in speech timing, but it may stem from a more basic temporal disorder (R. D. Kent, 1984). We compared the ability of stuttering and nonstuttering adults to estimate protensity and to distinguish the relative lengths of short tones. We also examined whether there is a correlation between a person's degree of disfluency and the ability to measure protensity or judge the relative lengths of short tones. Twenty stuttering and 20 nonstuttering adults were given the Duration Pattern Sequence Test. They were also asked to estimate the lengths of 8 tones and silent intervals. A negative correlation was found between degree of disfluency and ability to determine the relative lengths of short tones. A positive correlation was found between degree of disfluency and length of protensity estimates. KEY WORDS: disfluency, temporal processing, time estimation, stuttering, protensity, An important theory of stuttering suggests that it is not only overtly manifested as a disruption in the normal timing pattern of speech, but that it stems from a more [...]

The timing and intensity variability of 8 adults who stutter and 8 age-matched fluent speakers was investigated under metronomic conditions. Participants were required to produce double or triple-stress patterns at a slow speech rate (1 syllable/870 ms) when repeating the syllable /staet/ or /straet/ nine times. Measures that are sensitive to cyclic rather than overall variation in syllable timing and intensity were employed. Specifically, durational variation between successive syllable onsets as well as intensity variation of the beginning consonant and vowel in successive syllables were computed. Results revealed that, although intensity variation was similar, the timing of successive syllables of persons who stutter was significantly more variable than that of persons who do not stutter. These outcomes are discussed in relation to previous experiments of timing control of persons who stutter and normally fluent persons during metronomic stimulation. KEY WORDS: stuttering, speech timing, variability, metronome, Although we are intuitively aware of rhythmic constraints in speech production, our knowledge of the exact nature of these constraints and how they are controlled remains scant. Much of our [...]

The purpose of the present study was to investigate the impact of utterance length and syntactic complexity on the speech motor stability of adults who stutter. Lower lip movement was recorded from 8 adults who stutter and 8 normally fluent controls. They produced a target phrase in isolation (baseline condition) and the same phrase embedded in utterances of increased length and/or increased syntactic complexity. The spatiotemporal index (STI) was used to quantify the stability of lower lip movements across multiple repetitions of the target phrase. Results indicated: (a) Adults who stutter demonstrated higher overall STI values than normally fluent adults across all experimental conditions, indicating decreased speech motor stability; (b) the speech motor stability of normally fluent adults was not affected by increasing syntactic complexity, but the speech motor stability of adults who stutter decreased when the stimuli were more complex; (c) increasing the length of the target utterance (without increasing syntactic complexity) did not affect the speech motor stability of either speaker group. These results indicate that language formulation processes may affect speech production processes and that the speech motor systems of adults who stutter may be especially susceptible to the linguistic demands required to produce a more complex utterance. The present findings, therefore, support the hypothesis that linguistic complexity is one factor that contributes to the disruptions of speech motor stability characteristic of stuttering. KEY WORDS: stuttering, fluency, linguistic complexity, kinematics, speech motor control, For the past 50 years, researchers have attempted to discover the relationship between linguistic variables and overt stuttering behaviors. Early experiments focused primarily on the properties of stuttered words. For [...]

The purpose of the present study was to develop and evaluate an instrument for assessing the communicative suitability of speech (i.e., the speaking situation-dependent adequacy of speech as judged by listeners). Listeners judged the suitability of speech of people who stutter (N = 10) at three stages of treatment (before, immediately after, and 6 months after) and that of people who do not stutter (N = 10, the latter serving as a reference). The listeners rated the suitability of the speech, using a 10-point scale, for 10 speaking situations that supposedly make different demands, with listeners consisting of three groups: unsophisticated listeners (N = 17), clinicians specializing in the treatment of stuttering (N = 17), and stuttering listeners (N = 17). Results indicate that the rating instrument can be scored reliably. Analysis of variance for the ratings of the reference speakers showed that the factor "situation" had a significant effect on the suitability ratings, with more demanding situations receiving lower suitability scores than the less demanding ones. Also, the speech of the people who stutter was judged significantly less suitable than the speech of the reference speakers. Furthermore, unsophisticated listeners were considerably less tolerant in their judgments than clinicians and stuttering listeners. Findings suggest that communicative suitability is a promising criterion to further investigate, especially as it may apply to the objective evaluation of treatment outcome for stuttering. KEY WORDS: stuttering, speech fluency, speech quality, evaluation of speech, evaluation of stuttering

The majority of work that suggests a relationship between syntactic complexity and the frequency of stuttering has been carried out with young children. In this paper, we investigate whether or not syntactic complexity exerts an influence on the frequency of stuttering in adolescent speech. Fourteen adolescents, 7 of whom stuttered, and 7 of whom were normally fluent, ages 10-18 years, participated in a sentence imitation task in which stimuli were divided into three classes of grammatical complexity. Results indicated that for both groups of speakers, normal disfluencies and errors in repetition accuracy increased as syntactic complexity increased. However, stuttering frequency did not appear to be affected by changes in the syntactic complexity of the target stimuli. Such findings suggest either a diminution of the effects of syntactic complexity on stuttering over the course of language acquisition or changes in the mix of chronic and nonchronic stuttering speakers from those used in earlier studies of the effects of linguistic structure on stuttering in children. KEY WORDS: stuttering, language, adolescents, syntax, fluency