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Biomedical subjects

A M Donahue

Publications and source records attributed to A M Donahue.

9 recordsLinked to original sources

Performance of two rapid, single-use immunoassays for the detection of Clostridium difficile toxin A.

Two rapid, single-use immunoassays for C. difficile toxin A, the Clearview C. DIFF A (Wampole Laboratories, Cranbury, N.J.) and the ImmunoCard Toxin A assays (Meridian Diagnostics Inc., Cincinnati, Ohio) were compared to the cytotoxin assay for their ability to detect C. difficile toxin in fecal specimens. A total of 537 specimens were tested and 47 (8.8%) were positive by the cytotoxin assay. The sensitivity, specificity, positive predictive value, and negative predictive value of the toxin A assays were as follows: 70.2% (95% CI, 57.1 to 83.3), 98.8% (95% CI, 97.8 to 99.8), 84.6% (95% CI, 73.3 to 95.9), and 97.2% (95% CI, 95.7 to 98.6) respectively for the Clearview assay; and 74.5% (95% CI, 62.0 to 86.9), 99.0% (95% CI, 98.1 to 99.9), 87.5% (95% CI, 77.3 to 97.8), and 97.6% (95% CI, 96.2 to 98.9) respectively for the ImmunoCard assay. Both toxin A assays are less sensitive than the cytotoxin assay, however, these assays offer a rapid and easy-to-perform test that may be used in conjunction with the cytotoxin assay for laboratory confirmation of C. difficile-associated disease.

Bacterial Toxins↗

Assessment of the proposed Draft American National Standard method for evaluating the effectiveness of hearing conservation programs.

Using audiometric data, this study assessed the Draft American National Standard ANSI S12.13-1991 (DANS) method for evaluating the effectiveness of hearing conservation programs by comparing it against a standard epidemiologic method. Although the hearing conservation program of the study population was rated as "acceptable" (scale: acceptable, marginal, unacceptable) using the DANS method, the epidemiologic method found a 130% increased risk of hearing loss (relative risk = 2.3, 95% confidence interval = 0.8 to 6.5). In addition, study workers who were excluded from analyses for failing to comply with the DANS criteria were found to be at significantly increased risk of hearing loss (relative risk = 9.1, 95% confidence interval = 3.4 to 24.2). These data indicate that the DANS method may overestimate the effectiveness of hearing conservation programs and systematically exclude workers at high risk of hearing loss from analyses.

Adult↗

An epidemiologic method for assessing the effectiveness of hearing conservation programs using audiometric data.

A hearing conservation program (HCP) must include audiometric monitoring. In keeping with this requirement, enormous bodies of audiometric data have been accumulated. However, only a limited number of methods are available for using audiometric data to assess HCP effectiveness. This study illustrates an epidemiologic method. The risk of developing hearing loss (measured by the standard threshold shift) was compared between study and reference populations using the risk ratio. The study population had an increased risk of nearly 3-fold. Epidemiologic risk comparison methods, using reference populations, offer an alternative to current methods for HCP evaluation using audiometric data.

Adult↗

Comparison of amplification systems in an auditorium.

Intelligibility of speech at two positions in a large auditorium was compared for the public address system (PA) and two assistive listening systems: Frequency modulation of radio frequencies (FM) and modulation of infrared light waves (IR). Listening groups were: normal-hearing adults, hearing-impaired, hearing aid users, elderly, and non-native. Word-identification scores were obtained with the Modified Rhyme Tests. Analysis of variance indicated that the main effects of systems, groups, and listening position were significant. Also significant were the two-way interactions. For all groups, the assistive listening systems provided better scores than the PA system. The difference between the two systems was statistically significant, but very small. It can be concluded that both listening systems provide improved speech intelligibility for various types of listeners.

Acoustic Stimulation↗

Comparison of amplification systems in a classroom.

"Listening systems" are used for hearing impaired listeners as an alternative to public address systems (PA) used for the general public. These listening systems allow individual control of sound pressure level and minimize the effects of background noise and room reverberation. Three listening systems, based on an audio induction loop (AL), frequency modulation of radio frequencies (FM), and modulation of infrared light (IR) were compared among themselves and with a PA system in a medium-size classroom. Listening groups were normal hearing, hearing impaired, hearing aid users, and elderly. Word identification scores were obtained with the Modified Rhyme Test at two conditions: with a babble of 12 voices at a speech-to-noise ratio (S/N) of + 8 dB, and without the babble at S/N of +20 dB. Analysis of variance indicated that the main effects of systems, groups and room S/N were significant. Also significant were interactions of systems by groups, and systems by S/N. For all groups, the three listening systems provided better scores than the PA system. It can be concluded that all three of the tested listening systems are suitable for listeners with various degrees of hearing losses.

Acoustic Stimulation↗

Induction loop listening system designed for a classroom.

The principles of designing an induction loop listening system are discussed. Step-by-step procedures for building an induction loop are presented. The loop described was installed in a medium-size classroom and listening tests were performed comparing the loop and loudspeakers. Two groups of hearing impaired listeners were used. One group of listeners wore hearing aids while the other group did not. Result indicated that for both groups, speech perception was enhanced with the loop system.

Correction of Hearing Impairment↗

Vibrotactile performance by normal and hearing-impaired subjects using two commercially available vibrators.

The aim of this study was to measure vibrotactile sensitivity and stress pattern recognition of untrained normal-hearing and hearing-impaired subjects. Vibrotactile thresholds were measured as a function of frequency with two vibrators at three body placements. Stress pattern recognition was tested with two vibrators at two body placements. Vibrotactile threshold results indicate that wrist placements were less sensitive than fingertip placement and the hearing-impaired subjects were equally or less sensitive than the normal-hearing subjects. Vibrator plunger size had the greatest effect on threshold in the most sensitive frequency range of the skin. Stress pattern recognition results indicate that subject performance is a function of body placement but not a function of plunger size. Moreover, stress pattern recognition curves obtained in this study had lower plateaus for the hearing-impaired subjects than for the normal-hearing subjects. Implications for vibrotactile training are discussed.

Adult↗

Tepid sponging.

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Baths↗