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Biomedical subjects

P L Michael

Publications and source records attributed to P L Michael.

14 recordsLinked to original sources
PubMed1984

Reference threshold sound pressure levels for the Welch Allyn AudioScope.

The Welch Allyn AudioScope has been evaluated as an audiometer screening instrument using a threshold, loudness balancing technique. Two sets of eartips have been compared to determine which eartip configuration would yield the most reliable audiometric data. The AudioScope has also been evaluated by the American National Standard Method for Coupler Calibration of Earphones using both sets of eartips, and reference threshold sound pressure levels for the AudioScope were developed by combining the coupler and loudness balance data. The most reliable eartip configuration for audiometric purposes is identified and guidelines for use of the audiometric screening instrument are proposed.

Audiometry↗
PubMed1980

Permanent effects of noise exposure on results of a battery of hearing tests.

Industrial noise exposures may result in permanent hearing impairment caused by changes at the inner ear or cochlea. Research at the Environmental Acoustics Laboratory has shown that measurements of audiometric thresholds alone may not be an adequate indicator of hearing changes due to noise exposure, especially in the early stages of developing, noise-induced, hearing impairment. In response to this observation a battery of tests sensitive to several parameters of hearing has been developed at the Environmental Acoustics Laboratory for use in characterizing and identifying auditory effects of noise exposure. Prior to the present investigation, the use of the testing battery had been restricted to the examination of temporary, noise-induced, hearing impairments under carefully controlled laboratory conditions. The present work reports on the use of the testing battery with clinical patients known to have a history of high-level noise exposure. Generally, the usefulness of the testing battery outside of the laboratory setting and with untrained listeners was demonstrated in this investigation. Details of the procedure for presenting the testing battery components are discussed.

Adult↗
PubMed1980

Hearing protector performance--an update.

A single-number descriptor, the A-weighted sound pressure level, has been used widely during the last 10 years for the assessment of noise exposure levels. Prior to that time octave band levels were the common means for describing noise exposures. Hearing protector noise reduction data have been presented in various ways to facilitate the calculation of exposure levels while wearing hearing protectors. This paper describes both single-number and octave band procedures for presenting hearing protector noise attenuation data and discusses advantages and disadvantages of each.

Auditory Threshold↗
PubMed1977

Loudness Discrimination Index (LDI): a test for the early detection of noise susceptible individuals.

Work has been completed at the Environmental Acoustics Laboratory during the past year on developing an industrially feasible Loudness Discrimination Index (LDI) Test. Data obtained on experimental subjects who had been exposed to brief, high-level sound showed that the maximum Loudness Discrimination Index Shift (LDIS-Max.) is a valid and reliable indicator of temporary, noise-induced, hearing change. This test is better suited to industrial usage than the traditional TTS test. Suggestions for the implementation of LDI testing in the industrial setting are discussed.

Auditory Threshold↗
PubMed1976

A procedure for the early detection of noise-susceptible individuals.

Currently used threshold audiograms fail to detect the early stages of noise-induced hearing impairment. Threshold shifts may reach 10 to 15 dB before the impairment is detected. Loudness difference limen and critical band phenomena should provide an earlier and more sensitive test for such hearing impairment.

Auditory Perception↗
PubMed1976

The effect of high level sound exposure on the loudness difference limen.

Currently used threshold audiograms fail to detect the early stages of noise-induced hearing impairment. Threshold shifts may reach 10 to 15 dB before the impairment is detected. Loudness difference limen and critical band phenomena may provide an earlier and more sensitive test for such hearing impairment. Data is reported which shows that the difference limen shift (DLS) due to noise persists longer than temporary threshold shift (TTS). These findings suggest that DLS may be a more feasible tool for industrial use than either TTS or monitoring audiometry.

Auditory Perception↗
PubMedDate not supplied

Noise in the news.

Explore the source record for details and available documents.

Legislation as Topic↗
PubMedDate not supplied

The AudioScope: a clinical tool for otoscopic and audiometric examination.

The AudioScope was evaluated both in laboratory and in clinical settings. Audiometric calibration of the instrument proved to be reliable and easy to accomplish. Clinic evaluation with 182 subjects demonstrated that audiometric screening with the AudioScope shows good agreement with conventional, clinical audiometry. The instrument is a useful clinical adjunct to audiometry since it generally categorizes audiogram configuration and level and provides insight into subject cooperation. This information can enhance the efficiency of manual, threshold audiometry, especially in pediatric cases.

Adolescent↗
PubMedDate not supplied

Noise attenuation characteristics of the MX-41/AR and the Telephonics circumaural audiometric headsets.

Masking from background noise is often a serious problem when hearing levels are measured at or near the low reference threshold levels specified in the American National Standards Specifications for Audiometers, ANSI S3.6-1969. Since background noise limits for audiometric test rooms are inversely related to the noise reduction characteristics of the earphone/cushion assemblies, it is important that these units have significant and consistent attenuation properties. This paper reports the noise reduction characteristics measured for the conventional TDH-39 earphone mounted in the supra-aural MX-41/AR cushion and for the new TDH-50 Telephonics circumaural headset. The circumaural headset was found to produce an average of about 10 dB more noise attenuation than did a well-adjusted supra-aural device, and the circumaural headset provided much more consistent test-retest noise reduction characteristics. Theoretical aspects of headband force as well as the implications of attenuation measurements for test room recommendations are discussed.

Adult↗