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Biomedical subjects

D B Hawkins

Publications and source records attributed to D B Hawkins.

At least 37 records · Page 2Linked to original sources
PubMed1989

Use of probe tube microphone measurements in hearing aid selection for children: some initial clinical experiences.

Some initial experiences are described in which ear canal probe tube microphone measurements are used to determine hearing aid settings for children. Decisions are based upon ideas developed by Seewald and Ross (in Amplification for the Hearing Impaired, New York: Grune & Stratton, 1988: 213-267) and Seewald, Ross, and Stelmachowicz (J Acad Rehab Aud 1987;20:25-37) in which the long term spectrum of speech is amplified to desired sensation levels. Case results from four children are used to demonstrate the application and usefulness of the procedure.

Amplifiers, Electronic↗
PubMed1989

Advances in sinus disease in pediatrics.

Advances in sinus diseases in pediatrics during the 1980s have occurred in both diagnosis and treatment. Perhaps the most significant development in diagnosis has been the increased sophistication of computerized tomography. In treatment, the most significant advances have been in the better understanding of the bacteriology of pediatric sinusitis and the development of endoscopic sinus surgery.

Child↗
PubMed1988

New hearing aid users' perception of the "hearing aid effect".

The negative attitude elicited by the presence of a hearing aid has been termed the "hearing aid effect." The purpose of this study was to examine the negative reactions associated with hearing aids among new hearing aid users themselves and their perception of the hearing aid effect in their immediate environment. This was accomplished through a questionnaire completed just prior to hearing aid fitting and again 6 months after initial use of amplification. The responses to the questionnaires were compared between individuals who had chosen either in the ear or behind the ear type hearing aids, and between those using either monaural or binaural instruments. The effect of age on the data was also examined. The results indicated that the hearing aid effect was not expected or perceived very widely among these subjects, as only about 10% of them reported sensing negative attitudes to the use of hearing aids. Positive responses to the benefits of hearing aid use from other people often fell short of expectations.

Adult↗
PubMed1987

An evaluation of residue features as correlates of voice disorders.

Two experiments were conducted to assess the correlations of residue features with some perceptual properties of voice disorders. First, 90 samples of the vowel /a/ produced by patients with various vocal pathologies were analyzed to obtain the residue features, and severity judgments of these vowel samples were obtained. The results of linear multiple regression analysis indicated that the features were highly correlated with the severity ratings. Second, an attempt was made to correlate the residue features with voice qualities. The features were calculated for the vowel /a/ produced by patients with vocal nodules, vocal fold paralysis, and vocal polyps and by normal talkers. Each vowel sample was rated on ten scales of voice quality. The results revealed high correlations among the quality scales so that discrete subject groups could not be formed. Thus, residue features may be useful in assessing the degree of vocal impairment, but their use as correlates of voice quality must await further research.

Adolescent↗
PubMed1987

Examination of two issues concerning functional gain measurements.

The test-retest variability of aided sound-field thresholds and the feasibility of using corrected 2-cm3 coupler gain values to predict individual functional gain were examined. Test-retest data were used to generate critical differences (in dB) for statistical significance between two aided sound-field thresholds. To be significantly different at the .05 level, two aided thresholds would have to differ by greater than 15 dB. Functional gain and 2-cm3 coupler gain were compared for 20 subjects using careful measurement procedures. Individual variability in the difference between functional gain and 2-cm3 coupler gain was reduced substantially from previous studies and indicates that corrected coupler gain measurements may have some clinical utility.

Adult↗
PubMed1987

Binaural loudness summation in the hearing impaired.

Binaural loudness summation was measured using three different paradigms with 10 normally hearing and 20 bilaterally symmetrical high-frequency sensorineural hearing loss subjects. An adaptive paradigm and a loudness matching procedure measured summation at the lower and upper level of comfortable loudness and the loudness discomfort level (LDL). Monaural and binaural LDLs also were obtained with a clinical procedure designed to select maximum output of hearing aids. Stimuli for all three tasks consisted of 500- and 4000-Hz pure tones and a speech spectrum noise. Binaural summation increased with presentation level using the loudness matching procedure, with values in the 6-10 dB range. Summation decreased with level using the adaptive paradigm, and no summation was present with the clinical LDL task. The hearing-impaired subjects demonstrated binaural summation that was not significantly different from the normally hearing subjects. The results suggest that a bilaterally symmetrical sensorineural hearing loss does not affect binaural loudness summation. The monaural and binaural dynamic range widths were similar, and the LDL results suggest that binaural loudness summation may not be an important factor in selecting maximum output of hearing aids.

Acoustics↗
PubMed1987

Formant frequencies of stuttered and fluent vowels.

The formant frequencies of 15 adult stutterers' fluent and disfluent vowels and the formant frequencies of stutterers' and nonstutterers' fluent vowels were compared in an F1-F2 vowel space and in a normalized F1-F2 vowel space. The results indicated that differences in formant frequencies observed between the stutterers' and nonstutterers' vowels can be accounted for by differences among the vocal tract dimensions of the talkers. In addition, no differences were found between the formant frequencies of the fluent and disfluent vowels produced by the stutterers. The overall pattern of these results indicates that, contrary to recent reports (Klich & May, 1982), stutterers do not exhibit significantly greater vowel centralization than nonstutterers.

Adult↗
PubMed1987

Description and validation of an LDL procedure designed to select SSPL90.

A new procedure is described for measuring loudness discomfort levels (LDLs) for the purpose of selecting SSPL90 characteristics of hearing aids. The person is seated in sound field wearing a high-output hearing aid (with a known amount of 2 cm3 coupler gain) connected to a personal earmold. The loudness of frequency-specific signals is rated from a series of loudness category descriptors. The LDL is defined in terms of SPL developed in a 2 cm3 coupler, thus making selection of SSPL90 from hearing aid specification sheets practical. Experiments on LDL stability over time and validation of the SSPL90 selection are reported.

Adult↗
PubMed1987

Assessment of FM systems with an ear canal probe tube microphone system.

A technique is described to measure the real-ear performance of an FM system using an ear canal probe tube microphone device. The method involves placement of the FM microphone next to the monitoring (compression) microphone of the probe tube assembly to produce a constant sound pressure level input to the FM system. With the probe tube in the ear canal, a hearing aid alone is measured with a 60 dB SPL input and the FM system attached to the hearing aid (personal FM system) is assessed with an 80 dB SPL input to account for the higher input levels that occur due to the 6 inch distance between the speaker's mouth and the FM microphone. This technique permits a rapid comparison of the real-ear response of the hearing aid and the FM system.

Ear Canal↗
PubMed1987

Clinical ear canal probe tube measurements.

This paper describes a variety of areas in which ear canal probe tube microphone measurements can be useful to the audiologist. Areas such as measurement of hearing aid insertion gain to match some predetermined target levels, output sound pressure level in the ear canal (real ear SSPL90), and assessment of FM systems and FM system-hearing aid combinations are discussed. In addition, some variables affecting the accuracy of these measurements and the reliability will be discussed.

Acoustics↗
PubMed1987

Representations of the long-term spectra of speech.

Numerous and somewhat different representations of the long-term spectra of speech are available in the literature. Various estimates of speech spectra have been converted to a consistent audiogram format for presentation here. Even so, plots of speech spectral levels across the frequency region of 125 to 8000 Hz vary considerably. Bases for some of these variations and clinical utilization of a speech spectrum are discussed.

Auditory Threshold↗
PubMed1987

Speech recognition in noise and reverberation by school-age children.

The present study examined the effects of noise (S/N ratio = +2 and +6 dB) and reverberation time (Rt = 0.0 and 0.8 s) on monaural speech recognition in normal-hearing school-age children (aged 8-10 years) using sentence materials. Our data confirm the results of other studies which suggest that the typical acoustic conditions existing in classrooms do not permit adequate speech recognition. The introduction of a typical level of classroom reverberation significantly reduced speech recognition in both levels of noise. These results have implications regarding the clinical assessment of communicative function in hearing-impaired children.

Acoustics↗
PubMed1986

Coins in the esophagus. What is the best management?

In order to compare esophagoscopy to the Foley catheter method of removing coins from the esophagus, we reviewed our results with 136 esophagoscopies performed to remove coins during a 15-year period. Fifty-two percent of the patients were under two years of age and 29% were under one year. One hundred and twenty-seven patients had no problems from the anesthesia or the esophagoscopy. Complications related to the endotracheal tube and exacerbations of pre-existing respiratory illnesses occurred in 9 patients. There were no deaths or esophageal perforations. Our results are compared to the published results from the Foley catheter method. In our opinion, esophagoscopy is the procedure of choice for all children with coins in the esophagus.

Catheterization↗
PubMed1986

Tracheotomy in infants and young children: the changing perspective 1970-1985.

One hundred fifty-three children 3 years of age or younger who had tracheotomies performed during the past 15 years are reviewed. During this time, short-term endotracheal intubation for airway obstruction from acute infections and long-term intubation for patients on ventilators have replaced early tracheotomy for these conditions. The number of tracheotomies decreased during each of three 5-year periods, from 73 to 55 to 25, respectively. Improvements in medical management resulted in prolonged survival of children with multiple abnormalities and resulted in more prolonged tracheotomies. Early complications occurred in 12% of patients and late complications occurred in 26%. In spite of changes in the indications, basic fundamentals of pediatric tracheotomy management remain unchanged.

Airway Obstruction↗