PubMed Health⌕ Search

Biomedical subjects

D B Hawkins

Publications and source records attributed to D B Hawkins.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of sound quality judgments for monaural and binaural hearing aid processed stimuli.

Fifteen adults with bilaterally symmetrical mild and/or moderate sensorineural hearing loss completed a paired-comparison task designed to elicit sound quality preference judgments for monaural/binaural hearing aid processed signals. Three stimuli (speech-in-quiet, speech-in-noise, and music) were recorded separately in three listening environments (audiometric test booth, living room, and a music/lecture hall) through hearing aids placed on a Knowles Electronics Manikin for Acoustics Research. Judgments were made on eight separate sound quality dimensions (brightness, clarity, fullness, loudness, nearness, overall impression, smoothness, and spaciousness) for each of the three stimuli in three listening environments. Results revealed a distinct binaural preference for all eight sound quality dimensions independent of listening environment. Binaural preferences were strongest for overall impression, fullness, and spaciousness. Stimulus type effect was significant only for fullness and spaciousness, where binaural preferences were strongest for speech-in-quiet. After binaural preference data were obtained, subjects ranked each sound quality dimension with respect to its importance for binaural listening relative to monaural. Clarity was ranked highest in importance and brightness was ranked least important. The key to demonstration of improved binaural hearing aid sound quality may be the use of a paired-comparison format.

Acoustics↗
PubMed1992

Comparison of SSPL90 selection procedures.

Recommended SSPL90 values were determined at 500, 1000, and 2000 Hz for 16 subjects with mild-to-moderate sensorineural hearing losses using six different selection procedures, including an Upper Limit of Comfortable Listening (ULCL) and threshold-based procedure by Cox (1988), a threshold-based procedure by Seewald and Ross (1988), and loudness discomfort procedures by Berger (1988), McCandless and Lyregaard (1983), and Hawkins et al (1987) and Libby (1985). Statistically significant differences were found among the procedures at 500 and 2000 Hz. Analysis of individual data showed that while some subjects obtained similar recommended SSPL90s across the procedures, others showed dramatically different values.

Adult↗
PubMed1991

Abscesses of the neck in infants and young children. A review of 112 cases.

A review of 112 patients 5 years of age and younger with cervical abscesses is reported. Staphylococcus aureus and group A beta-hemolytic Streptococcus were cultured most often: in 39% and 17% of patients, respectively. Sixteen patients (14%) had unusual abscesses such as infected congenital cysts, cat-scratch disease, or myocobacterial abscesses. One patient had a necrotizing infection with group A streptococci and anaerobic streptococci. Intravenous antibiotic therapy was used in 104 patients, with 94% of these patients receiving a penicillin derivative, usually an antistaphylococcal penicillin. Ninety-six percent of the patients had incision and drainage of their abscesses; 8 patients required more than one incision and drainage. Two patients required airway intervention, 1 by intubation and 1 by trachetomy. Most pediatric cervical abscesses respond well to appropriate intravenous antibiotic therapy and incision and drainage.

Abscess↗
PubMed1991

Effect of reference microphone location and loudspeaker azimuth on probe tube microphone measurements.

The effects of loudspeaker azimuth and reference microphone location on probe tube microphone measures were assessed. The real ear unaided response (REUR), real ear aided response (REAR), and real ear insertion response (REIR) were obtained on a KEMAR. Aided measures were obtained with both a behind-the-ear and an in-the-ear hearing aid. All three measurements were affected by changes in the loudspeaker azimuth and reference microphone location. Responses obtained with a 90 degree loudspeaker azimuth or with the reference microphone located at-the-ear revealed greater disparity than those obtained under other conditions. Most of the differences occurred at frequencies above 2000 Hz, with measurements utilizing the behind-the-ear hearing aid showing greater dispersion. These results suggest that the location of the loudspeaker and the reference microphone are important variables when utilizing probe tube microphone measurements.

Acoustics↗
PubMed1990

Visual biasing of normal and impaired auditory speech perception.

Intersensory biasing occurs when cues in one sensory modality influence the perception of discrepant cues in another modality. Visual biasing of auditory stop consonant perception was examined in two related experiments in an attempt to clarify the role of hearing impairment on susceptibility to visual biasing of auditory speech perception. Fourteen computer-generated acoustic approximations of consonant-vowel syllables forming a /ba-da-ga/ continuum were presented for labeling as one of the three exemplars, via audition alone and in synchrony with natural visual articulations of /ba/ and of /ga/. Labeling functions were generated for each test condition showing the percentage of /ba/, /da/, and /ga/ responses to each of the 14 synthetic syllables. The subjects of the first experiment were 15 normal-hearing and 15 hearing-impaired observers. The hearing-impaired subjects demonstrated a greater susceptibility to biasing from visual cues than did the normal-hearing subjects. In the second experiment, the auditory stimuli were presented in a low-level background noise to 15 normal-hearing observers. A comparison of their labeling responses with those from the first experiment suggested that hearing-impaired persons may develop a propensity to rely on visual cues as a result of long-term hearing impairment. The results are discussed in terms of theories of intersensory bias.

Adult↗
PubMed1990

Complex and pure-tone signals in the evaluation of hearing-aid characteristics.

In recent years, a number of commercially available systems have been developed to analyze the electroacoustic characteristics of hearing aids. In addition to pure-tone signals, these systems often use a wide variety of complex signals such as broadband noise, clicks, and multitonal complexes. In this paper, a number of practical and theoretical issues concerning the use of pure-tone and complex signals in the evaluation of hearing-aid characteristics are described. The circumstances under which discrepancies in estimated gain and maximum output might occur using these two types of signals are described and the clinical implications of these differences are discussed.

Algorithms↗
PubMed1990

Removal of blunt foreign bodies from the esophagus.

Historically, removal of blunt foreign bodies from the esophagus by esophagoscopy under general anesthesia has been considered to be relatively safe and effective. In recent years, alternative techniques of blind removal with balloon catheters or bougies have been advocated. This paper reports 246 esophagoscopies performed over a 19-year period to remove blunt esophageal foreign bodies. Eighty-one percent of the foreign bodies were coins and 74% were in children under 3 years of age. There were no deaths, no perforations, and no instances of mediastinitis. The only complications encountered were those due to esophageal erosion and/or respiratory problems secondary to long-standing foreign bodies. In the author's opinion, esophagoscopy is the best method for removal of all esophageal foreign bodies. There simply does not seem to be a need for alternative methods involving blind removal.

Adolescent↗
PubMed1990

Familial vocal cord dysfunction associated with digital anomalies.

Familial vocal cord dysfunction is a rare condition that has been reported in only a few instances. This is a report of identical male twins, both of whom had congenital bilateral abductor vocal cord paresis associated with finger deformities. The vocal cord paresis progressed to paralysis that required tracheotomy, then returned to a slowly resolving paresis during which the vocal cords had uncoordinated motion generally known as synkinesis. Another male sibling and the mother had a history of stridor during infancy and finger deformities. Several other relatives had digital abnormalities, and an infant first cousin with finger abnormalities required a tracheotomy for vocal cord paralysis.

Diseases in Twins↗
PubMed1990

Avoiding a wrapped endotracheal tube in laser laryngeal surgery: experiences with apneic anesthesia and metal laser-flex endotracheal tubes.

Ninety-one laser laryngeal procedures using the apneic technique of anesthesia were performed in 28 patients between 2 months and 64 years of age. Seventy-two procedures (79%) were performed on children and 19 on adults. There were no complications. Eight laser laryngoscopies were performed using a new metal Laser-Flex endotracheal tube. Obstruction of the endotracheal tube with a mucous plug occurred in one case. The apneic technique described in this paper provides a laser operative field free of an endotracheal tube, virtually eliminating the danger of a laser fire. It is a relatively safe and effective means of performing laser laryngeal surgery. In addition, the Laser-Flex endotracheal tube appears to be an acceptable alternative to a metallic tape-wrapped endotracheal tube.

Adolescent↗
PubMed1990

Comparisons among SPLs in real ears, 2 cm3 and 6 cm3 couplers.

Sound pressure levels (SPLs) were measured in the ear canals of 30 adult subjects with standard audiometric earphones (TDH-39) and insert earphones (Etymotic ER-3A) and compared to those generated in 2 cm3 and 6 cm3 couplers. Transfer functions are shown for real ear to 2 cm3 coupler, real ear to 6 cm3 coupler, 6 cm3 to 2 cm3 coupler, and dB HL under standard earphones to 2 cm3 coupler SPL. In general, the data agreed rather well with published transfer functions that in most cases were derived by adding together a series of partial transfer functions from various studies. The conversion values from dB HL to 2 cm3 coupler SPL could be useful in selection of certain hearing aid parameters, but the intersubject variability may limit their usefulness somewhat.

Adult↗
PubMed1989

Basilar skull fractures in children.

In this paper we are reporting a retrospective study of patients under 18 years of age managed at the Los Angeles County/University of Southern California Medical Center from January 1979 through December 1987 with the diagnosis of basilar skull fracture. Sixty-two patients with basilar skull fractures were admitted during that 7 1/2 year period. The most common etiology was pedestrain versus vehicle accidents (42%), followed by falls (27%), vehicle accidents (23%), and being hit by an object (8%). The most common physical findings were hemotympanum (58%) and bleeding in the ear canals (47%). Thirty-four percent of the patients complained of hearing loss. Cerebrospinal fluid otorrhea was noted in 16 patients (26%), while only 1 patient had cerebrospinal fluid rhinorrhea. Facial nerve paralysis was present in 8 patients (13%). Vestibular symptoms were rare. Sixty-three percent of the patients had the diagnosis confirmed by radiography. The clinical presentation, complications, management and outcome of basilar skull fractures in the pediatric population are discussed.

Adolescent↗
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↗