Andrew Stuart

Effects of alterations in auditory feedback and speech rate on stuttering frequency.

This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates. Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Stuttering amelioration at various auditory feedback delays and speech rates

The primary purpose of this study was to determine if the finding of Kalinowski et al. (1993) of dramatic reductions in stuttering under delayed auditory feedback (DAF) at normal and fast speech rates could be replicated. The second purpose was to determine if stuttering frequency is differentially affected by various delays in an attempt to identify the optimal delay for fluency enhancement for both normal and fast speech rates. Fourteen adult stutterers read eight different passages at either a normal or fast speech rate under non-altered auditory feedback (NAF) and DAF with delays of 25, 50 and 75 ms. Results showed that significant fluency enhancement occurred under DAF at both normal and fast speech rates at all DAF settings (p < 0.05). This finding corroborates the notion that a slowed rate of speech is not a necessary antecedent for fluency improvement under conditions of altered auditory feedback. In addition, the results indicated that 50 ms appears to be the shortest delay producing the maximum reduction in stuttering frequency.

Stereotypes of stutterers and nonstutterers in three rural communities in Newfoundland

Abstract The existence of a negative stereotype of stutterers among residents of three small, rural communities in Newfoundland, Canada was investigated. Members of these communities (n = 106) completed a 25-item semantic differential scale developed by Woods and Williams (1976) which asked them to rate a hypothetical adult male stutterer and nonstutterer. Results indicated that community members perceived hypothetical stutterers in a negative manner in comparison to nonstutterers, despite the fact that 85% of the respondents reported knowing stutterers and 39% reported being related to stutterers. It is suggested the negative stuttering stereotype exists because nonstutterers generalize state to trait anxiety, and because of the nature of the stuttering moment itself. Since this study and previous studies appear to show that the stereotype is not modified by exposure to stutterers, familial relationships, and/or educational background, further research is needed to determine what, if any factor, can modify the pervasive negative stereotype.

Effects of Age, Gender, Bolus Volume, Bolus Viscosity, and Gustation on Swallowing Apnea Onset Relative to Lingual Bolus Propulsion Onset in Normal Adults.

The purpose of this study was to ascertain the normal relation of swallowing apnea (SA) onset relative to lingual bolus propulsion along with factors that may alter this relation. Forty adults, composed of 10 men and 10 women in each of 2 age groups (i.e., 20-30 and 63-79 years) participated. SA onset was assessed during 5- and 20-ml bolus volumes of water and apple juice across 3 trials. The effects of age, gender, bolus volume, bolus viscosity, and gustation on SA onset relative to lingual bolus propulsion were examined. A significant interaction of Age x Gender x Volume was found. In general, older adults initiated SA onset earlier than young adults, and large boluses elicited an earlier SA onset than small boluses regardless of group. Young men demonstrated significantly later SA onset than the older men for large volumes; this difference was not observed for small volumes, nor was it found between young and older women. SA onset also was assessed during 5-ml bolus volumes of thin apple juice, thick apple juice, and applesauce across three trials. A significant main effect of viscosity was found revealing that SA onset was initiated later as bolus viscosity increased. Thus, the results of this investigation provided data on the relation of SA onset relative to lingual bolus propulsion in individuals with normal swallowing and how this relation changes as a function of age, gender, bolus volume, bolus viscosity, and gustation.

Effect of delayed auditory feedback on normal speakers at two speech rates

This study investigated the effect of short and long auditory feedback delays at two speech rates with normal speakers. Seventeen participants spoke under delayed auditory feedback (DAF) at 0, 25, 50, and 200 ms at normal and fast rates of speech. Significantly two to three times more dysfluencies were displayed at 200 ms (p<0.05) relative to no delay or the shorter delays. There were significantly more dysfluencies observed at the fast rate of speech (p = 0.028). These findings implicate the peripheral feedback system(s) of fluent speakers for the disruptive effects of DAF on normal speech production at long auditory feedback delays. Considering the contrast in fluency/dysfluency exhibited between normal speakers and those who stutter at short and long delays, it appears that speech disruption of normal speakers under DAF is a poor analog of stuttering.

Investigations of the impact of altered auditory feedback in‐the‐ear devices on the speech of people who stutter: initial fitting and 4‐month follow‐up

BACKGROUND Self-contained ear-level devices delivering altered auditory feedback (AAF) for the application with those who stutter have only been recently developed. AIMS The paper examines the first therapeutic application of self-contained ear-level devices in three experiments. The effect of the device on the proportion of stuttered syllables and speech naturalness was investigated following initial fitting and at 4 months post-fitting. METHODS & PROCEDURES Three experiments were undertaken: In Experiment 1, the effect of a self-contained in-the-ear device delivering AAF was investigated with those who stutter during reading and monologue. Two adolescents and five adults who stuttered read and produced monologue with and without a device fit monaurally. The device provided a frequency shift of +500 Hz in combination with a delayed auditory feedback of 60 ms. Custom-made ITC and CIC devices were fabricated for four adults and four youths in Experiment 2. The effect of group (i.e. youth versus adult), time (i.e. initial fitting versus 4-month follow-up), speech task (i.e. reading versus monologue), and device (i.e. present versus absent) on stuttering rate was examined. In Experiment 3, 15 naïve listeners rated the speech naturalness of speech produced by the participants in Experiment 2. Speech samples from six conditions were rated: reading and monologue without the device at the initial visit, reading and monologue with the device at the initial visit, and reading and monologue with the device at 4 months. OUTCOMES & RESULTS In Experiment 1, the proportion of stuttered syllables was significantly (p=0.011) reduced by approximately 90% during reading and 67% during monologue with the device relative to no device. Only a significant main effect of device (p=0.0028) was found in Experiment 2. That is, stuttering rate was significantly reduced with the device in place regardless of speech task or group and remained so 4 months later. In Experiment 3, speech samples generated while wearing the device were judged to be more natural sounding than those without the device (p<0.0001) for reading and monologue with both adults and youths. There was no significant difference between the mean naturalness ratings of speech samples generated during the initial fitting with the device relative to that at 4 months with the device (p>0.05) in all cases except with the youths while engaged in monologue. For that condition, raters judged the speech produced at the initial fitting as more natural. CONCLUSIONS These findings support the notion that a self-contained in-the-ear device delivering AAF assists those who stutter. With the device in place, stuttering is reduced and speech produced is judged to be more natural than with out the device.

Effect of single and combined altered auditory feedback on stuttering frequency at two speech rates

The purpose of this study was to determine if combining delayed auditory feedback (DAF) and frequency altered feedback (FAF) would enhance fluency more than either DAF or FAF alone. Ten stutterers read at normal and fast speech rates under nonaltered auditory feedback (NAF), DAF (i.e., a 50 ms delay), FAF (i.e., a one half octave downward shift), and a combination of DAF and FAF [(COMBO), i.e., a 50 ms delay plus a one half octave downward shift]. Results indicated that stuttering frequency was significantly reduced under all altered auditory conditions at high speech rates relative to the NAF condition. There were, however, no significant differences between the altered auditory feedback conditions (i.e., DAF, FAF, and COMBO). It is suggested that further studies be undertaken to explore the combination of altered auditory feedback conditions, as it may be the case that a floor effect was demonstrated with the singular presentations of DAF and FAF and further improvements in fluency enhancement could not be exhibited in the combined condition. Finally, these findings support the notion that a slowed rate of speech is not necessary for fluency enhancement under conditions of altered auditory feedback.

Penetration and Aspiration in Healthy Older Adults as Assessed during Endoscopic Evaluation of Swallowing

Objectives: A previous article from our group presented data on normal swallowing as assessed during simultaneous manometry and flexible endoscopic evaluation of swallowing (FEES). Because penetration and aspiration events were identified in healthy adults, the question arose, could the presence of the manometric catheter confound normal FEES findings? Thus, a follow-up study was designed to address the effects of catheter condition on healthy older adults as assessed during FEES. Methods: Twenty older adults (mean, 78.9 years of age) participated. The participants each contributed 28 swallows, affording a study total of 560 swallows for analyses. Results: The older adults demonstrated penetration on 82 (15%) and aspiration on 18 (3%) of 545 swallows. The numbers of participants who had penetration and aspiration during the study protocol were 75% and 30%, respectively. The older adults demonstrated both penetration and aspiration events irrespective of the presence of a catheter; whether they were drinking milk, water, or barium; whether the bolus was 5 or 10 mL; and whether they took the bolus via syringe or self-administered the bolus with a cup. However, significantly more aspiration was found on thin liquids than on puree or solids. Conclusions: Endoscopic data on normal swallowing physiology were generated. These may serve as an accurate benchmark for clinicians and researchers in the interpretation of dysphagia.

Effect of monaural and binaural altered auditory feedback on stuttering frequency

The effect of monaural and binaural alterations in auditory feedback on stuttering frequency was investigated. Eleven participants who stutter read aloud under nonaltered auditory feedback (NAF) and monaural and binaural conditions of frequency altered feedback [(FAF), on-quarter octave shift upward] and delayed auditory feedback [(DAF), 50-ms delay] at a normal speech rate. Relative to the NAF condition, reductions in stuttering frequency of approximately 60%-75% were found with the altered auditory feedback conditions. Post hoc single-df comparisons revealed a reduction in stuttering frequency with altered auditory feedback versus NAF (p < 0.0001), a greater reduction in stuttering frequency for binaural compared to monaural altered auditory feedback (p = 0.028), and nonsignificant differences in stuttering frequencies for right versus left monaural conditions (p = 0.54) and DAF versus FAF (p = 0.70).

The effect of an educational patient compliance program on serum phosphate levels in patients receiving hemodialysis

OBJECTIVE This study sought to determine the effectiveness of a recently developed educational patient compliance program (A Taste for Life [1995]; Abbott Laboratories, Abbott Park, IL) on improving serum phosphate levels in patients receiving hemodialysis. DESIGN An ABA time series design was used. PARTICIPANTS/SETTING Eighty-one patients receiving hemodialysis participated. The experimental group consisted of 50 participants (mean [M] = 57.9 years of age; 92% African-American; 62% female) from a private freestanding dialysis unit (Kinston, NC). The control group consisted of 31 control participants (M = 58.2 years of age; 90% African-American; 48% female) from a separate private freestanding dialysis unit (Greenville, NC). INTERVENTION The experimental group took part in the educational patient compliance program directed at dietary and medical regimes. The program used educational materials, interactive educational modules, motivational posters, creative games and puzzles, videos, and an in-center achievement contest. The control group did not partake in the program, but received individual ongoing monthly therapy that involved nutrition counseling consistent with the National Renal Diet (American Dietetic Association, 1993) and instruction regarding use of phosphate binders. MAIN OUTCOME MEASURE Serum phosphate levels were monitored monthly for 1 year (ie, 3, 3, and 6 months during pretreatment, treatment, and posttreatment, respectively). RESULTS No statistically significant differences were found in serum phosphate levels between the two groups (P >.05). There was, however, a significant difference across time within groups. Mean serum phosphate levels significantly declined during the treatment period and further during the posttreatment period relative to the pretreatment baseline (P <.05). Results were not compared with a group of patients receiving hemodialysis who received no nutrition counseling. CONCLUSION The findings suggest that an educational compliance program is equally effective as standard individual ongoing counseling in affecting serum phosphate levels among patients with end-stage renal disease who receive hemodialysis. Results suggest that renal dietitians choose types of intervention within each patients continuity of care that support individual success.