Biomedical subjects

J E Widen

Publications and source records attributed to J E Widen.

9 recordsLinked to original sources

PubMed1995

Progressive neural hearing impairment: case report.

This report describes a patient whose ability to understand speech had so deteriorated over 20 years time that she was being considered for a cochlear implant, despite the fact that pure-tone sensitivity loss had not deteriorated proportionately. An unusual combination of otoacoustic emissions (OAEs) and auditory evoked potential (AEP) results are described. Click-evoked and distortion product emissions were present and normal-appearing. Auditory brainstem and middle latency responses were totally absent but the N1-P2 complex of the long-latency response was present. The case illustrates the contribution of otoacoustic emissions to site of lesion testing. It also illustrates that the manifestations of pathology can appear in certain epochs of the family of AEPs without affecting the others.

Adult↗

PubMed1993

Adding objectivity to infant behavioral audiometry.

This article deals with the limitations of infant behavioral audiometry, which have led us to seek objective methods of audiometry for determining hearing sensitivity in infants. It describes efforts to add objectivity to (or reduce the subjectivity of) behavioral methods of infant audiometry. Several aspects of visual reinforcement audiometry (VRA), including the head turn response, the use of control trials, and adherence to the principles of operant conditioning, serve to reduce the subjectivity inherent in behavior observation audiometry. In addition, computer control of VRA procedures can relieve the examiner of potentially subjective decision-making during the course of evaluation and can facilitate testing with sophisticated algorithms that could not be done manually by a single examiner. Computer simulations to determine the best VRA test parameters are described.

Acoustic Stimulation↗

PubMed1991

Optimization of automated hearing test algorithms: simulations using an infant response model.

Computer simulation was used to evaluate several parameters of an automated hearing test algorithm in an attempt to optimize the algorithm for accuracy and efficiency. An infant response model was developed to guide the simulations. Test parameters of interest were starting intensity and stopping rule and their interaction with a measure that is thought to emulate infant reliability, probability of task orientation. Results indicated that stopping rule, within the ranges investigated, had little effect on accuracy but had major impact on efficiency. Starting intensity interacted with the hearing status of pseudosubjects in influencing accuracy. Accuracy was most influenced by probability of task orientation. The simulated test data are compared to data from infants and young children in the accompanying article so that the response model can be evaluated.

Algorithms↗

PubMed1991

Optimization of automated hearing test algorithms: a comparison of data from simulations and young children.

A five-up, five-down automated staircase procedure was used to explore the effects of variable starting and stopping rules as they interact with infant behavior in influencing the accuracy and efficiency of infant auditory threshold testing. Results from 146 infants were compared to results from computer simulations (see accompanying article) in order to evaluate an infant response model used in the simulations. Results indicate that the automated procedure successfully discriminated between infants with normal versus abnormal tympanograms. In addition, the model accurately predicted infant results in terms of the effects of starting and stopping rules. The model was less useful in predicting the relationship between minimum response levels and false positive rates.

Algorithms↗

PubMed1990

Evoked otoacoustic emissions in normal-hearing infants and children: emerging data and issues.

Evoked otoacoustic emissions (EOAEs) are a promising tool for evaluating cochlear status in children. Preliminary data from normal-hearing subjects ranging from birth to 29.9 years old are discussed. EOAEs are present and robust in infant ears. However, there is a statistically significant decrease in EOAE amplitude for a fixed stimulus level with increasing age even in a carefully screened sample. At the present time it is unclear if these age-associated changes are due to normal developmental changes in the external and/or middle ear acoustics, normal developmental changes in cochlear mechanics and/or everyday cochlear wear and tear. Issues related to further application of evoked emissions to pediatric populations are discussed.

Adolescent↗

PubMed1990

Computer methods for on-line hearing testing with auditory brain stem responses.

On-line computer methods were developed and evaluated for automated hearing testing with auditory brain stem responses (ABR). The system contained (1) a response recognition unit which recognized the presence or absence of an ABR response and (2) a threshold tracking unit which adjusted stimulus intensity and determined the ABR threshold. Two methods, one nontemplate (variance ratio) and one template (cross-correlation), were evaluated for response recognition while three threshold tracking methods were explored: clinical, Békésy, and PEST (parameter estimation by sequential testing). Both response recognition and threshold tracking units were evaluated by computer simulations for on-line operation using a standard set of experimentally recorded ABRs. The results indicated that while all the response recognition methods were reasonably accurate, their on-line use resulted in significant differences in test efficiency due to differences in tracking methods.

Acoustics↗

PubMed1988

Assessment techniques to evaluate tactual aids for hearing-impaired subjects.

In order to optimize the use of tactual aids for the deaf, it is important to have a battery of assessments to determine the potential contribution of the aids to acoustic perception and speech identification. We have designed such a battery to be used with young hearing-impaired children. The tasks were developed so that they could be implemented with standard audiometric equipment and applied to subjects of varying age and to different types of tactual aids. Illustrative results from four profoundly hearing-impaired children showed that tactual vocoders allowed detection of high frequencies that were not available to the subjects through aided audition. In most cases with these subjects, performance on simple detection and discrimination tasks showed facilitative effects with tactual vocoders. Facilitative effects were further evidenced in more complex phonemic identification tasks for all subjects. The tasks can be used to determine possible benefits of tactual aids for individual hearing-impaired children.

Auditory Perception↗

PubMed1987

Auditory brainstem responses in young adults with Down syndrome.

Auditory brainstem response (ABR) wave V detection levels, latency, and amplitude were studied in a group of 15 young adults with Down syndrome for whom behavioral measures of hearing sensitivity were also obtained. Comparisons were made to a group of nonretarded control subjects matched by age and sex. Auditory brainstem response detection levels were elevated, response amplitude was reduced, and latency-intensity functions were significantly steeper for the subjects with Down syndrome than for the control group. These findings were associated with a high frequency (8000 Hz) hearing loss prevalent in the otherwise normal-hearing experimental group.

Adolescent↗

PubMed1983

Auditory brain-stem responses in infants with Down's syndrome.

Auditory brain-stem responses to clicks were recorded from 38 infants with Down's syndrome at the ages of 3, 6, and 12 months in an attempt to delineate age-dependent and intensity-dependent latency changes in this population. Comparisons were made with 35 normally developing infants at the same age levels. Significant wave V latency differences were observed between groups for both age and intensity, with the group with Down's syndrome showing, in general, shorter absolute wave V latency values across age and steeper latency functions across intensity. The implications of this study are as follows: (1) latency-intensity curves for normally developing infants will not serve adequately as normative values for infants with Down's syndrome, particularly at the age of 12 months, and (2) cochlear function in infants with Down's syndrome may differ from normal infants by the age of 12 months.

Acoustic Stimulation↗