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Biomedical subjects

A Stuart

Publications and source records attributed to A Stuart.

At least 19 recordsLinked to original sources
PubMed2000

Stutter-free and stutter-filled speech signals and their role in stuttering amelioration for English speaking adults.

This study examined the power of an exogenously generated stuttered speech signal on stuttering frequency when compared to an exogenously generated normal speech signal. In addition, we examined the specific components of the second speech signal, which might be responsible for the inducement of fluency in people who stutter. Eight males and two females who stuttered participated in this study. Experiment I involved meaningful speech: normal continuous speech, normal interrupted speech, stuttered continuous speech, and stuttered interrupted speech, whereas Experiment II involved vowels and consonants: /a/, /a-i-u/, /s/, /s-sh-f/. The results indicated that stuttered and normal speech signals were equally effective in reducing stuttering frequency. Further, the vowels were more powerful than consonants in inducing fluency for people who stutter. It is suggested that acoustic manifestations of stuttering, rather than a problem, may be a natural compensatory mechanism to bypass or inhibit the 'involuntary block' at the neural level.

Adult↗
PubMed2000

Inducement of fluent speech in persons who stutter via visual choral speech.

A novel phenomenon of fluency enhancement via visual gestures of speech in the absence of traditional auditory feedback is reported herein. The effect on visual choral speech on stuttering frequency was investigated. Ten participants who stuttered recited memorized text aloud under two conditions. In a visual choral speech (VCS) condition participants were instructed to focus their gaze on the face, lips and jaw of a research assistant who 'silently mouthed' the text in unison. In a control condition, participants recited memorized text to the research assistant who sat motionless. A statistically significant (P=0.0025) reduction of approximately 80% in stuttering frequency was observed in the VCS condition. As visual linguistic cues are sufficient to activate the auditory cortex, one may speculate that VCS induces fluency in a similar yet undetermined manner as altered auditory feedback does.

Adult↗
PubMed2000

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 patient's continuity of care that support individual success.

Adult↗
PubMed2000

Evaluation of a direct doctor-patient telephone advice line in general practice.

A general practitioner-staffed direct access telephone advice line was made available for 30 minutes every morning at an inner-London practice to advise patients with urgent problems. Users valued the service, but the impact on surgery consultations was too small for this to be advocated as an alternative to emergency consultations.

Family Practice↗
PubMed1999

The effects of venting on in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shell frequency responses: real-ear measures.

The acoustic effects of 1-, 2-, and 3-mm vents were investigated with in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shells. Real-ear sound pressure level measures were obtained from unvented and vented shells with 12 adults. In general, with increasing vent size, a statistically significant (p < .05) increase in the amount of low-frequency reduction, an upward shift in vent cutoff frequencies, and an upward shift in vent-associated resonances occurred for all hearing aid shell styles. There was no significant change in the slope of the low-frequency reduction across all hearing aid shell styles (p > .05), albeit the frequency response curves were shifted upward in frequency with increasing vent diameters. Only with the in-the-ear and completely-in-the-canal hearing aid shells were statistically significant (p < .05) differences found with the magnitude of vent-associated resonance as a function of vent diameter, and these differences were not consistent across the different styles. These findings suggest that venting may be used effectively to tune low-frequency responses in custom in-the-ear hearing instruments.

Adult↗
PubMed1999

Effects of monitoring condition and frequency-altered feedback on stuttering frequency.

The purpose of the study was to examine stuttering frequency during speaking conditions that are believed to mitigate stuttering frequency both with normal nonaltered auditory feedback (NAF) and a known fluency-enhancing feedback. Specifically, stuttering frequency was examined as a function of three monitoring conditions under NAF and frequency-altered feedback (FAF): no monitoring (i.e., speaking alone, in the absence of audio and visual recording), audiovisual monitoring (i.e., speaking alone with audiovisual recording), and audiovisual monitoring with observers (i.e., speaking with audiovisual recording in the presence of two observers). Seven adults and one adolescent who stutter served as participants. Stuttering frequency was differentially affected across monitoring conditions under each auditory feedback condition (p = .027). Post hoc analyses revealed no significant difference in stuttering frequency between the two conditions in the absence of the observers (i.e., no monitoring vs. audiovisual monitoring) under NAF (p = .45). There was, however, a significant difference in stuttering frequency for the no-monitoring and audiovisual-monitoring conditions relative to the audiovisual-monitoring-with-observers condition (p = .0002). There was no statistically significant difference in stuttering frequency across monitoring conditions under FAF (p > .05). The findings are consistent with the notion that during NAF stuttering frequency varies as a function of hierarchical socio-environmental conditions in which inanimate monitoring conditions constitute one entity. Such a relationship does not exist during FAF.

Adult↗
PubMed1998

Effect of extended exposure to frequency-altered feedback on stuttering during reading and monologue.

An ABA time series design was used to examine the effect of extended, continuous exposure to frequency-altered auditory feedback (FAF) during an oral reading and monologue task on stuttering frequency and speech rate. Twelve adults who stutter participated. A statistically significant decrease in number of stuttering events, an increase in number of syllables produced, and a decrease in percent stuttering was observed during the experimental segment relative to baseline segments for the oral reading task. In the monologue task, there were no statistically significant differences for the number of stuttering events, number of syllables produced, or percent stuttering between the experimental and baseline segments. Varying individual patterns of response to FAF were evident during the experimental segment of the reading task: a large consistent reduction in stuttering, an initial reduction followed by fluctuations in amount of stuttering, and essentially no change in stuttering frequency. Ten of 12 participants showed no reduction in stuttering frequency during the experimental segment of the monologue task. These findings have ramifications both for the clinical utilization of FAF and for theoretical explanations of fluency-enhancement.

Adult↗
PubMed1998

Quantitative electroencephalogram of posterior cortical areas of fluent and stuttering participants during reading with normal and altered auditory feedback.

In the left and right hemisphere, posterior quantitative electroencephalogram Beta band activity (13.5-25.5 Hz) of seven adult participants who stutter and seven age-matched normal controls was obtained while subjects read text under three experimental conditions of normal auditory feedback, delayed auditory feedback, and frequency-altered feedback. Data were obtained from surface electrodes affixed to the scalp using a commercial electrode cap. Electroencephalogram activity was amplified, band-pass analog-filtered, and then digitized. During nonaltered auditory feedback, stuttering participants displayed Beta band hyperreactivity, with the right temporal-parietal lobe region showing the greatest activity. Under conditions of delayed auditory feedback and frequency-altered auditory feedback, the stuttering participants displayed a decrease in stuttering behavior accompanied by a strong reduction in Beta activity for the posterior-temporal-parietal electrode sites, and the left hemisphere posterior sites evidenced a larger area of reactivity. Such findings suggest than an alteration in the electrical fields of the cortex occurred in the stuttering participants under both conditions, possibly reflecting changes in neurogenerator status or current dipole activity. Further, one could propose that stuttering reflects an anomaly of the sensory-linguistic motor integration wherein each hemisphere generates competing linguistic messages at hyperreactive amplitudes.

Adolescent↗
PubMed1998

A latent trait approach to the development of persistent stuttering.

The premise that stuttering disorders develop according to the orthogenetic principle, preceding in a continuous, unilinear fashion from a state of relative lack of differentiation to a state of increasing differentiation and hierarchic integration, was examined. Responses to Woolf's Perceptions of Stuttering Inventory of 87 individuals who stutter were analyzed using a Rasch 1980 latent trait model for dichotomously scored data. Analyses of responses indicated struggle, avoidance, and expectation through the development of stuttering that became increasingly articulated, integrated, stable, and yet responsive to environmental changes. Four stages of development were noted: Stage I was characterized by the expectation of interruptions in the flow of speech, the addition of unnecessary sounds, and general body tension. Stage II was typified by distinctions between troublesome and not so troublesome words and sounds and between the speaker and various audiences and contexts for speaking. In Stage III, speech control decreased despite more focused and complex efforts to control the environment and the speech apparatus. Stage IV was characterized by automatic scanning of all speech, increasingly uncontrolled body movements, and attempts to produce fluent speech by way of comprehensive changes to sound, rhythm, and pitch. Follow-up of 29 respondents suggested the latent struggle was generally stable over time.

Adolescent↗
PubMed1998

Recognition of temporally distorted words by listeners with and without a simulated hearing loss.

In separate experiments, word recognition performance of two groups of 12 normal-hearing young adults was investigated as a function of temporal distortion (i.e., time compression ratio or reverberation time) with and without a simulated high-frequency hearing loss (i.e., low-pass filtered at 2000 Hz). Performance decreased significantly as a function of increasing time compression, reverberation, and with the simulated hearing loss (p < .05). A statistically significant interaction between each of time compression ratio and reverberation time with the filtered listening condition was found (p < .05). This finding of an interactive, as opposed to a simple additive, effect of multiple distortions of the speech on word recognition performance suggests that loss of audibility alone cannot account for decrements in word recognition performance with time-altered speech. It is suggested that this multiplicative effect for combined acoustic distortions is a consequence of the functional loss of the high-frequency region of the cochlea. Not only is there a loss of audibility, but there is also a loss in temporal resolution capacity since it is perception mediated through the population of high-frequency auditory channels that has the best temporal resolution.

Adult↗
PubMed1998

Effects of contralateral speech competition on auditory event-related potentials recorded from elderly listeners: brain map study.

Topographic brain mapping was used to investigate the ability of young and elderly female listeners to attend to tones at one ear in the presence of speech competition at the opposite ear. An oddball stimulus presentation paradigm was used to record the N1, P2, and P300 components of the late auditory evoked potential from 19 scalp locations. With speech competition, elderly listeners exhibited significantly larger reductions in N1 amplitude than did young listeners. This suggests that N1 may provide an electrophysiologic index of age-related breakdowns in processing sounds in the presence of background competition. An unexpected difference was also found between young and elderly listeners in P300 scalp topography. While the young listeners' P300 response was centered at midline for both left and right ear stimulation, the elderly participants had P300 maxima centered in the parietal area of the hemisphere located contralateral to the test ear. This suggests that some of the functional properties (e.g., timing, strength, orientation) of the P300 neural generators may change with age or, alternatively, that different generators may be operative in elderly listeners.

Adult↗
PubMed1997

Effect of altered auditory feedback on people who stutter during scripted telephone conversations.

The effect of altered auditory feedback (AAF) conditions on stuttering during scripted telephone conversations was investigated. Nine adult participants made 15 scripted telephone calls to business in New York City. Alterations in the participants' auditory feedback signal were generated by a commercially available digital signal processor (Casa Futura Technologies Desktop Fluency System Model BTD-400) that shifted participants' speech one-half octave down in frequency, produced a 50-ms delay, or produced non-altered auditory feedback. The AAF effects produced by the digital signal processor were not perceived by the recipients of the telephone calls. The proportion of stuttering events per scripted telephone conversations were significantly reduced in the AAF conditions relative to the non-altered auditory feedback condition (p = .0004). Stuttering frequency was reduced by 55% and 60% for the FAF and DAF, respectively. These findings demonstrate the applicability of this technology to situations of daily living involving telephone use.

Adult↗
PubMed1997

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).

Adolescent↗
PubMed1997

Formant frequency characteristics of elderly speakers in contextual speech.

The present study measured F1 and F2 formant frequency levels of elderly and young male and female speakers producing the /i/, /ae/, [symbol: see text], /u/, and /a/ vowels in two carrier phrases. Results of a series of ANOVAs showed significant interactions of speaker age x vowel for both F1 and F2 formant frequencies for the male and female speakers. Results suggested that while elderly male speakers exhibit significant alterations in vowel production during contextual speech, elderly female speakers generally maintain formant frequency integrity or appropriate articulatory posturing during contextual vowel productions.

Adult↗
PubMed1997

Effect of speaking into a passive resonator on stuttering frequency.

The effect on stuttering frequency of speaking into a passive resonator was investigated. Eight participants who stuttered read aloud with and without the benefit of the resonator. A statistically significant reduction of approximately 30% in stuttering frequency was observed while the participants spoke with the resonator. These and similar commercially available devices may be employed with individuals who stutter, particularly children, as a means of enhancing fluency.

Adolescent↗
PubMed1997

Word recognition in continuous noise, interrupted noise, and in quiet by normal-hearing listeners at two sensation levels.

The effect of presentation level on word recognition performance-intensity functions in continuous and interrupted broadband noise and in quiet was explored. Normal-hearing participants were tested at 30 and 50 dB sensation levels (SLs). Performance-intensity functions in both noises were determined at signal-to-noise ratios (S/Ns) of 10, 5, 0, -5, -10, -15, and -20 dB. There was no effect of SL presentation on word recognition performance in quiet (p = 0.136). A significant main effect was observed for S/N in both continuous and interrupted broadband noise conditions (p < 0.0001). Performance increased with increases in S/N regardless of the competing noise condition. A significant main effect for SL presentation was only observed in the interrupted noise condition (p = 0.0019). That is, performance was higher for the 50 SL for the interrupted noise condition only. It is suggested that the observed difference in performance in interrupted noise at different SLs offers additional evidence for level-dependent, temporal masking phenomena.

Hearing↗