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Bradley McPherson

Publications and source records attributed to Bradley McPherson.

11 recordsLinked to original sources
PubMed2006

Assessment of central auditory processing in a group of workers exposed to solvents.

CONCLUSION: Despite having normal hearing thresholds and speech recognition thresholds, results for central auditory tests were abnormal in a group of workers exposed to solvents. Workers exposed to solvents may have difficulties in everyday listening situations that are not related to a decrement in hearing thresholds. A central auditory processing disorder may underlie these difficulties. OBJECTIVE: To study central auditory processing abilities in a group of workers occupationally exposed to a mix of organic solvents. MATERIALS AND METHODS: Ten workers exposed to a mix of organic solvents and 10 matched non-exposed workers were studied. The test battery comprised pure-tone audiometry, tympanometry, acoustic reflex measurement, acoustic reflex decay, dichotic digit, pitch pattern sequence, masking level difference, filtered speech, random gap detection and hearing-in-noise tests. RESULTS: All the workers presented normal hearing thresholds and no signs of middle ear abnormalities. Workers exposed to solvents had lower results in comparison with the control group and previously reported normative data, in the majority of the tests.

Adolescent↗
PubMed2006

Organic solvents and hearing loss: The challenge for audiology.

Organic solvents have been reported to adversely affect human health, including hearing health. Animal models have demonstrated that solvents may induce auditory damage, especially to the outer hair cells. Research on workers exposed to solvents has suggested that these chemicals may also induce auditory damage through effects on the central auditory pathways. Studies conducted with both animals and humans demonstrate that the hearing frequencies affected by solvent exposure are different to those affected by noise, and that solvents may interact synergistically with noise. The present article aims to review the contemporary literature of solvent-induced hearing loss, and consider the implications of solvent-induced auditory damage for clinical audiologists. Possible audiological tests that may be used when auditory damage due to solvent exposure is suspected are discussed.

Animals↗
PubMed2006

Auditory processing tests for Spanish-speaking adults: an initial study.

There is no standardized material to assess auditory processing (AP) in Spanish-speaking adults. The purpose of this research was to develop and obtain initial normative data for AP tests for Spanish-speaking adults. The AP tests comprised the Hong Kong CAPA (Hong Kong central auditory processing assessment) including speech-in-noise, binaural fusion, filtered speech, and dichotic digit tests. In addition five tests already developed by other authors, but with no normative data reported for the target population, were included in the study. These tests were staggered spondaic words, random gap detection, pitch pattern sequence, duration pattern sequence, and masking level difference. Forty normal hearing Chilean adults were assessed to obtain the initial normative data. Several correlations were found between tests and between subtests within the same test category. 90th percentiles are suggested as initial normative data.

Adult↗
PubMed2005

Audiological status of Chinese patients with cleft lip/palate.

OBJECTIVE: To review the audiological and otoscopic status of Chinese children and young adults seen at a cleft lip and palate clinic in Hong Kong and compare with previous studies of Western clinical populations. DESIGN: The hearing health status of the patients was analyzed on the basis of the results of their otoscopic, pure tone audiometric, and tympanometric examinations. The patients' sex, age, race, and type of cleft pathology were examined for their potential relationship to hearing health status. PARTICIPANTS: The records of 180 predominantly Chinese patients attending the Cleft Lip and Palate Centre, Prince Philip Dental Hospital/University of Hong Kong from July 1977 to December 1999 were reviewed. RESULTS AND CONCLUSION: The results indicated 13.4% of patient ears failed the audiometric screening and 23.7% of patient ears yielded abnormal tympanometric results. Patients' sex, age, and type of cleft pathology were found not to be related to hearing screening results. The prevalence of hearing disorder was in contrast with Western studies that show a much higher rate of audiological problems in children and young adults with cleft lip/palate. Racial factors were considered to be possible reasons for this disparity. Other factors, such as timely medical and surgical intervention, including early cleft palate repair and the insertion of ventilation tubes in cases of middle ear effusion, do not convincingly account for the study findings.

Acoustic Impedance Tests↗
PubMed2004

Auditory neuropathy/auditory dys-synchrony in school children with hearing loss: frequency of occurrence.

OBJECTIVE: The frequency of occurrence of a recently identified hearing disorder, auditory neuropathy/auditory dys-synchrony (AN/AD), was investigated in children with hearing impairment in Hong Kong. METHODS: In this study, 56 students, aged 7-18 years, attending primary divisions in schools for the hearing impaired were screened using otoacoustic emission procedures. RESULTS: One student in the study group was found to have intact outer hair cell function. A detailed diagnostic assessment of this case strongly suggested AN/AD was involved. Combining the study results with those of a previously conducted survey in Hong Kong, the frequency of occurrence of AN/AD in children attending schools for the hearing impaired was estimated to be 2.44% (3 out of 123 children screened). Estimates of the frequency of occurrence of AN/AD in various other educational settings in Hong Kong were also derived. CONCLUSIONS: The study indicates that AN/AD is not an extremely rare disorder. Educational audiologists and other health care professionals need to be actively involved in the identification and management of AN/AD. Research should be directed at technological innovations that may help to overcome the limitations of present screening procedures, in order to more accurately identify the disorder.

Acoustic Impedance Tests↗
PubMed2004

Occupational hearing loss: screening with distortion-product otoacoustic emissions.

Hearing assessment of applicants for occupational hearing loss compensation can be a time-consuming process. An accurate screening procedure that is sensitive to occupational hearing loss may have application in many situations. The present study developed distortion-product otoacoustic emission (DPOAE) screening criteria to identify subjects likely to meet the Hong Kong requirements for occupational hearing loss compensation, namely a bilateral sensorineural loss > or = 40 dB HL (average of 1000, 2000 and 3000 Hz). The screening criteria of 1500 and/or 2000 Hz, with a signal-to-noise ratio of > 0 or 3 dB, yielded high sensitivity and specificity. DPOAE measures therefore have the potential to accurately indicate possible occupational hearing loss. However, DPOAEs should be used as a screening tool only, as conventional puretone audiometry remains the more comprehensive measure of hearing sensitivity.

Adult↗
PubMed2003

Hearing aid satisfaction: what does research from the past 20 years say?

Hearing aid satisfaction is a pleasurable emotional experience as an outcome of an evaluation of performance. Many tools have been designed to measure the degree of satisfaction overall, or along the dimensions of cost, appearance, acoustic benefit, comfort, and service. Various studies have used these tools to examine the relationships between satisfaction and other factors. Findings are not always consistent across studies, but in general, hearing aid satisfaction has been found to be related to experience, expectation, personality and attitude, usage, type of hearing aids, sound quality, listening situations, and problems in hearing aid use. Inconsistent findings across studies and difficulties in evaluating the underlying relationships are probably caused by problems with the tools (eg, lack of validity) and the methods used to evaluate relationships (eg, correlation analyses evaluate association and not causal effect). Whether satisfaction changes over time and how service satisfaction contributes to device satisfaction are unclear. It is hoped that this review will help readers understand current satisfaction measures, how various factors affect satisfaction, and how the way satisfaction is measured may be improved to yield more reliable and valid data.

Journal Article↗
PubMed2002

Transient evoked otoacoustic emissions in children studying in special schools.

OBJECTIVES: The present study aimed to investigate the feasibility and practicalities of testing children in special school settings using transient evoked otoacoustic emissions (TEOAE) and tympanometry. Children studying in special schools, particularly those with intellectual impairment, may be highly susceptible to hearing pathologies and can be difficult to assess using traditional test batteries. Researchers have recently suggested the possible applicability of TEOAE testing, in lieu of conventional behavioral methods, as a hearing screening device for persons with intellectual impairment. However, to date, few publications have detailed the particulars and results of such testing. METHODS: A total of 489 children, with a mean age of 9.6 years, were tested in 15 special schools. Case information was obtained regarding birth history, medical history and type/degree of impairment, for later comparison with screening results. TEOAEs were collected using Quickscreen mode of the ILO292 Otodynamics Analyzer, whilst tympanometry was performed utilizing a Madsen Zodiac 901 Middle Ear Analyzer. RESULTS: In total, 80% of students were able to be tested using TEOAEs. Average test time per ear was 2 min. However, a large proportion (40% of those able to be tested) failed TEOAE testing in at least one ear. No significant effects were found between could-not-test (CNT) cases and case history factors. A significant difference in TEOAE failure rates was found across history of neonatal special care nursery residency and history of parental concern regarding possible hearing impairment. Failure rates were higher for those who indicated positive histories. A total of 74% of subjects could be tested using tympanometry, with 25% of those able to be tested failing in at least one ear. Notably, neither type nor degree of impairment had any significant bearing on CNT or failure rates for tympanometry or TEOAE screening. CONCLUSIONS: Findings of the present investigation lend support to the review of hearing screening programs for children in special schools, with TEOAEs presenting as a potential alternative procedure. Further examination of the performance measures of protocols incorporating TEOAEs would now be advantageous.

Acoustic Impedance Tests↗
PubMed2002

Handedness effects on transient evoked otoacoustic emissions in schoolchildren.

Handedness, as a potentially influencing, nonpathologic factor, has not been investigated in relation to transient evoked otoacoustic emissions (TEOAEs). The present study aimed to examine the effects of handedness on the TEOAE spectrum in entry-level schoolchildren, with attention also to possible ear asymmetry. A total of 228 subjects (114 males, 114 females, mean age = 6.3 years) were tested using the ILO292 Otodynamics Analyzer (Quickscreen mode) in quiet rooms in 22 schools. For statistical analysis, subjects were matched for factors such as handedness, gender, age, and history of recent ear infection. The results from subjects with passing TEOAE, pure-tone screening, and tympanometry revealed no significant handedness effect overall, although a significant ear asymmetry effect on the measurement parameters of AB difference, noise level, response level, whole-wave reproducibility, band reproducibility, and signal-to-noise ratios was found.

Acoustic Stimulation↗
PubMedDate not supplied

Seasonal effects on transient evoked otoacoustic emission screening outcomes in infants versus 6-year-old children.

The purpose of this study was to compare transient evoked otoacoustic emission (TEOAE) screening outcomes (pass/fail) across the seasons (spring, autumn, and winter) between infants and schoolchildren. A total of 526 infants (275 boys, 251 girls) with a mean age of 2.0 months (SD = 0.38 months) and 975 schoolchildren (513 boys, 462 girls) with a mean age of 6.2 years (SD = 0.36 years) were screened using the ILO Otodynamics Quickscreen program. The same TEOAE pass/fail criterion was applied to the two groups. The results indicated a significant difference in pass rates between infants (91.2% of 1052 ears) and schoolchildren (86.0% of 1950 ears). A seasonal effect was found only for schoolchildren, with a significantly lower pass rate in winter than in spring or autumn. There was no difference in pass rates between spring and autumn. Implications for the seasonal effect on TEOAE screening outcomes for infants and schoolchildren are discussed.

Acoustic Stimulation↗