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Biomedical subjects

B Hoover

Publications and source records attributed to B Hoover.

6 recordsLinked to original sources
PubMed2001

Some issues relevant to establishing a universal newborn hearing screening program.

This article describes some of the factors relevant to the establishment of a universal newborn hearing screening (UNHS) program. First, the difficulty in providing precise estimates of test sensitivity and specificity are reviewed. This section is followed by hypothetical estimates of overall programmatic costs, first for a fixed number of babies to be screened and then as a function of the number of babies to be screened in a year. Included in these estimates are the costs for equipment, disposables, personnel, and follow-up testing. These estimates are provided for three different screening protocols: auditory brainstem response (ABR) alone, otoacoustic emission (OAE) alone, and OAE followed by ABR only for those babies who failed the OAE screening. If follow-up costs are not included, it is less expensive to screen newborns with OAEs compared with the other two protocols. However, once follow-up testing is included as part of the program costs and there are at least 400 births per year, procedures in which OAEs are performed first, followed by an ABR on those infants who do not pass the OAE test, result in the lowest costs. Hospitals with as few as 400 births per year should expect per-baby costs not exceeding $30, regardless of which protocol is used. For all three protocols, the unit costs decrease as the number of babies screened increases. The final section describes data from a local UNHS program in which all infants are screened first with an OAE test, followed by an ABR test on infants not passing the OAE screening. Idiosyncratic features to this program are described, including the fact that all screening tests are performed by audiologists, who are paid on a part-time basis, adding cost to the program. Even under these circumstances, the unit cost is under $30. These data lead us to conclude that all infants can be screened in a cost-effective manner.

Cost-Benefit Analysis↗
PubMed1999

Subjective effects of peak clipping and compression limiting in normal and hearing-impaired children and adults.

Despite many advances in hearing-aid signal processing, compression limiting and peak clipping are still used. To date, perceptual studies have been conducted only with adults. The current study was designed to investigate the clarity of peak-clipped and compressed speech for both adults and children. Subjects were 30 normal-hearing and 30 hearing-impaired individuals in three age ranges (7-9, 10-12, and 16-50 years). Stimuli were processed at 60, 70, 75, and 80 dB SPL using peak clipping and at 80 dB SPL using compression limiting. Paired-comparison measures were used to assess the clarity of sentences, and a signal-to-distortion ratio (SDR) based on a measure of coherence between input and output was computed for each condition. For the peak-clipping conditions, there was a decrease in perceived clarity as the input increased from 60 to 80 dB SPL. This perceptual continuum was most apparent for the normal-hearing adults. The normal-hearing 10-12 year olds and the hearing-impaired adults showed a similar, but less pronounced, pattern. In contrast, the remaining three subject groups showed minimal differences in perceived clarity across conditions. Surprisingly, only the two oldest normal-hearing groups showed a clear preference for compression limiting over peak clipping at the highest input level, and only their results were consistent with the pattern of coherence across stimuli. Judgments of clarity by the normal-hearing subjects correlated best with the SDR in the 500-2000-Hz range, while clarity judgments of the hearing-impaired subjects correlated best with the SDR below 1000 Hz.

Adolescent↗
PubMed1997

From laboratory to clinic: a large scale study of distortion product otoacoustic emissions in ears with normal hearing and ears with hearing loss.

OBJECTIVES: 1) To describe distortion product otoacoustic emission (DPOAE) measurements in large groups of subjects with normal hearing and with hearing loss, and to use these data to provide comprehensive descriptions of DPOAE test performance. 2) To describe the effects of primary frequency and audiometric threshold on the extent to which DPOAE measurements accurately identify auditory status. 3) To develop an approach that describes the probability that any measured response is coming from either a normal or an impaired ear. 4) To develop an approach for representing DPOAE data clinically. 5) To explore the relation between magnitude of hearing loss and DPOAE measurements. DESIGN: DPOAE measurements were made in 1267 ears of 806 subjects, using stimulus conditions that previously had been demonstrated to result in the greatest separation between normal and impaired ears (i.e., primary levels of 65/55 dB SPL for f1/f2; Stover et al., 1996). Subjects were recruited from local clinical populations and through local advertisements. All data were analyzed using clinical decision theory, including relative operating characteristic (ROC) curves and estimates of areas under these curves (Az). In addition, cumulative distributions were constructed of response properties from both normal and hearing-impaired ears. These cumulative distributions were used to select specific probabilities that measured responses were coming from either the normal or impaired distributions, and to develop an approach for describing clinical DPOAE data. RESULTS: For no conditions were the distributions of DPOAE responses from normal and impaired ears completely separated, meaning that optimal criterion values would still result in errors in identification of auditory status. Test performance, defined by Az, was best for mid and high frequencies and poorest for lower frequencies and for the highest frequency tested (8000 Hz). Performance was best when normal hearing was defined as audiometric thresholds between 20 and 30 dB HL, with poorer performance for more stringent or lax audiometric criteria. CONCLUSIONS: Within the limits related to the effects of primary frequency and audiometric criterion, it appears that DPOAE measurements can be used to accurately identify auditory status. An approach is described, using the present data set, that allows one to assign to any measured DPOAE value (DPOAE amplitudes, DPOAE/noise) the probability that the response is coming either from the distribution of normal or impaired responses. In addition, DPOAE/noise systematically decreases as hearing loss increases over the range of hearing losses from 0 to about 40 to 60 dB HL (depending on frequency), thus potentially enabling one to differentiate hearing losses over this range. For hearing losses greater than 50 to 60 dB HL, ears do not produce measurable DPOAEs and thus, no predictive relationship exists.

Acoustic Stimulation↗
PubMed1993

A model for integrating technology into a multi-agency community service delivery system.

This article presents the results of a 4-year project to develop and test a model for integrating technology into a multi-agency community human services delivery system. "Technology" in this sense refers to both information technology and assistive technology. The project focused on systems change rather than on the creation of comprehensive assistive technology services. Several strategies of the model were developed and tested by the project. The project developed an information/communication tier that lay on top of the existing service delivery system. The information/communication tier was provided to agencies through an electronic network and searchable database, assistive technology advice-giving software, a public awareness campaign, and professional training. The results of these strategies are used to illustrate the Community Assistive Technology Services Network (CATSN) model. The model consists of five modules: 1) client assessment and technology examination, 2) professional and client training and technical assistance, 3) information and referral and needs analysis, 4) special projects, and 5) central coordination and facilitation--the hub. This model is important given recent nationwide initiatives for using assistive technology to provide people with disabilities opportunities for maximum independence, productivity, and integration.

Community Health Services↗