The influence of stuttering severity on acoustic startle responses

PURPOSE: This study examined the potential impact of stuttering severity, as measured by the Perceptions of Stuttering Inventory (Woolf, 1967) on acoustic startle responses. METHOD: Three groups, consisting of 10 nonstuttering adults, 9 mild stutterering adults, and 11 moderate/severe stutterering adults, were presented with identical 95-dB acoustic stimuli to elicit acoustic startle responses across 10 trials. Electromyographic recordings of orbicularis occuli activity were used to measure individual acoustic startle responses. RESULTS: Participant groups failed to exhibit statistically significant differences in initial acoustic startle response amplitude, mean acoustic startle response amplitude, habituation rates, and onset latency. Acoustic startle responses were characterized by high levels of variability across all participant groups but with highest levels of variability in the moderate/severe stuttering group. CONCLUSIONS: The current results suggest that stuttering severity, as measured in this study, does not effectively predict acoustic startle responses in groups of adults who stutter.     

Direct magnitude estimation and interval scaling of stuttering severity

The appropriateness of direct magnitude estimation and interval scaling for assessing stuttering severity was investigated by determining whether the continuum of the stutterers' judged severity was prothetic or metathetic. As operationally defined by Stevens, prothetic continua show a curvilinear relation between magnitude estimates and interval scale values of the same set of stimuli, whereas metathetic continua show a linear relation between these scale values. The stuttering severity of 20 stutterers was scaled by three groups of 15 listeners who used interval scaling, direct magnitude estimation with standard/modulus, and direct magnitude estimation without standard/modulus. The results indicated that the two sets of direct magnitude estimation scale values were related to the interval scale values in the curvilinear fashion that is typical of prothetic continua. These findings suggest that direct magnitude estimation is preferable to interval scaling for measuring stuttering severity.     

Acknowledgment and severity of stuttering as factors influencing nonstutterers' perceptions of stutterers

The purpose of this study was to determine (a) if nonstutterers prefer to interact with mild and severe stutterers who acknowledge their stuttering and (b) if nonstutterers' perceptions of mild and severe stutterers' intelligence, personality, and appearance are altered as a function of stutterers' acknowledgment of their stuttering. Acknowledgment and nonacknowledgment videotapes of two mild and two severe male stutterers were made during interview situations. Eighty-four female subjects examined the interview tapes and were then instructed to answer questions and complete adjective scales. Findings indicate that significant numbers of female nonstutterers prefer to interact with severe stutterers who acknowledged their stuttering. Mild and severe stutterers who acknowledged their stuttering receive more favorable ratings on intelligence, personality, and appearance.     

Variations in the relative speeds of orofacial structures with stuttering severity.

Stuttering can be characterized in part as a disorder in the coordination of different muscle systems. In light of basic aspects of orofacial physiology and development, the speeds of the lips and tongue relative to the jaw may be an important dimension for evaluating motor coordination among persons who stutter (PWS). To test this idea, an electromagnetic system was used to obtain measures of lip, tongue, and jaw speed in 38 adults (29 PWS and 9 normally fluent speakers, NFS) as they repeated a simple speech utterance at a normal rate. Using categorical ratings of stuttering severity, ratios of tongue speed to jaw speed were significantly greater in PWS rated as severe, compared to NFS and other PWS. Significant increases in lower lip-to-jaw and tongue-to-jaw speed ratios with stuttering severity were also reflected in correlation analyses relating speed ratios to a continuous measure of stuttering severity. These trends in speed ratio were related to increases in lower lip and tongue speed and decreases in jaw speed with stuttering severity. Sources of the speed differences are discussed in relation to underlying muscle activity, motor compensation processes in adults, and the development of orofacial motor control in children who stutter.     

Speech motor correlates of treatment-related changes in stuttering severity and speech naturalness

Participants of stuttering treatment programs provide an opportunity to evaluate persons who stutter as they demonstrate varying levels of fluency. Identifying physiologic correlates of altered fluency levels may lead to insights about mechanisms of speech disfluency. This study examined respiratory, orofacial kinematic and acoustic measures in 35 persons who stutter prior to and as they were completing a 1-month intensive stuttering treatment program. Participants showed a marked reduction in stuttering severity as they completed the treatment program. Coincident with reduced stuttering severity, participants increased the amplitude and duration of speech breaths, reduced the rate of lung volume change during inspiration, reduced the amplitude and speed of lip movements early in the test utterance, increased lip and jaw movement durations, and reduced syllable rate. A multiple regression model that included two respiratory measures and one orofacial kinematic measure accounted for 62% of the variance in changes in stuttering severity. Finally, there was a weak but significant tendency for speech of participants with the largest reductions in stuttering severity to be rated as more unnatural as they completed the treatment program.     

Speech clinicians' attribution of personality traits as a function of stuttering severity.

Thirty-six speech-language pathologists participated in a study to evaluate clinicians' preconceptions of persons who stutter. Each rated a designated construct (the normally fluent individual, the mild stutterer, the moderate stutterer, the severe stutterer) using a personality trait scale. Results indicated that clinicians stereotypically assign negative personality traits to all levels of stuttering severity relative to normal. Their ratings further demonstrated that stutterers are generally considered to be a homogenous group. Differentiation amongst stutterers was made only between the polar ends of the stuttering severity continuum (that is, mild vs. severe). Clinicians' sterotypical trait assignment was not related to their professional experience. Results are discussed with reference to their clinical implications.     

Effects of stuttering severity and therapy involvement on role entrapment of people who stutter

The primary purpose of this study was to examine whether a group of university students would report role entrapment of people who stutter (PWS) in the form of occupational stereotyping. The study also examined whether severity of stuttering (mild or severe) and level of therapy involvement (choosing or not choosing to attend therapy) affected the perceptions of role entrapment. To examine these issues, 260 students completed the Vocational Advice Scale (VAS) [Gabel, R. M., Blood, G. W., Tellis, G., & Althouse, M. T. (2004). Measuring role entrapment of people who stutter. Journal of Fluency Disorders, 29, 27-49]. Results suggested that stuttering severity and the level of therapy involvement did not appear alter the judges' reports for all of the careers except for the career of speech therapist. For the career of speech therapist, therapy involvement improved the participants' reports and stuttering severity had no effect. Additionally, findings suggested that university students reported that 16 of the careers listed on the VAS were appropriate choices for people who stutter and were less certain about advising for 27 of the careers. Thus, the findings from this study do not support the notion that stuttering leads to role entrapment in the form vocational stereotyping and variations in therapy involvement or stuttering severity do not change perceptions of role entrapment. LEARNER OUTCOMES: The reader will be able to (1) identify common stereotypes of PWS, (2) describe the possible effects of stereotyping and role entrapment, and (3) describe the effects of severity and therapy involvement of role entrapment of PWS.