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Biomedical subjects

J L Punch

Publications and source records attributed to J L Punch.

16 recordsLinked to original sources
PubMed1992

Prescriptive hearing aid fitting by parameter adjustment and selection.

We describe the rationale for the development of a psychophysical procedure that allows individual listeners to adjust the frequency-gain characteristic of a programmable hearing aid on a unidimensional scale, based on a target-gain reference value. The listener's task is to adjust the frequency response and select the parametric value judged to optimize the intelligibility or quality of speech. Originally described as the Sliding Scale, the procedure has been modified for use in reliability and validity studies of hearing aid fitting at Michigan State University. The modified approach is referred to as the Parameter Adjustment and Selection (PAS) procedure. Primary immediate goals for the procedure are ease of use, high reliability, and rapid clinical administration. The procedure, which may offer potential advantages over a paired-comparison approach, appears to be generally applicable to the fitting of digitally programmable hearing aids.

Auditory Threshold↗
PubMed1991

Evaluation of three strategies for fitting hearing aids binaurally.

Three strategies for evaluating optimum frequency shaping and noise reduction in binaural digital hearing aids were compared in a repeated-measures design, using a new preference-based prescriptive fitting method. These strategies consisted of using preferred frequency shaping and noise reduction values binaurally: (1) based on monaural testing; (2) based on separate evaluations of each ear; and (3) based on evaluation of a second ear while subjects wore an aid programmed with the preferred values in the first ear. Individually preferred characteristics were programmed for 17 hearing-impaired subjects, most of whom exhibited symmetrical sensorineural hearing loss. Each subject was administered intelligibility estimation and midplane localization measurements in the laboratory, as well as a questionnaire survey based on situational listening in the real world. No statistically significant differences in preferences for either frequency shaping or noise reduction were found for the three fitting strategies, suggesting that monaural testing is sufficient in symmetrical cases to provide information for binaural fitting. Related to this finding, differences across binaural conditions were minimal for both intelligibility estimation and localization results. A significant improvement in localization performance under binaural conditions over monaural listening, however, was documented by both the laboratory and the real world data. A strong overall preference for binaural over monaural amplification was also documented under real world conditions.

Adult↗
PubMed1988

The impact of digital technology on the selection and fitting of hearing aids.

The commercial availability of wearable digital hearing aids begins a new era in hearing aid technology. The impact of the introduction of digital technology extends from differences in hardware configuration to changes in the hearing aid fitting process to improvements in the perceptual experience enjoyed by the hearing-impaired individual. In this article, differences among analog, hybrid, and digital technology are reviewed. Performance differences among these technologies are examined in terms of flexibility, size, power consumption, programmability, and signal processing power. Emphasis is placed on the interdependence of hardware technology, signal processing algorithms, and the fitting procedure. The specific advantages of applying digital technology to fitting procedures are discussed. A number of perceptual and nonperceptual factors for the listener and the need to expand the history-taking process to identify performance-oriented patients are discussed. More rapid and reliable tests of patient preferences and speech intelligibility are needed for digital hearing aid fitting procedures.

Acoustics↗
PubMed1988

CROS revisited.

Explore the source record for details and available documents.

Acoustics↗
PubMed1987

Matching commercial hearing aids to prescriptive gain and maximum output requirements.

Insertion gain and saturation sound pressure level (SSPL) characteristics of 71 behind-the-ear hearing aids were evaluated in a computer-assisted analysis as acceptable matches to prescriptive insertion gain and SSPL values derived by a variation of the Prescription of Gain and Output, or POGO, technique (McCandless & Lyregaard, 1983). Stringency criteria in a primary analysis varied from +/- 6 to +/- 16 dB and +/- 2 to +/- 8 dB for gain and SSPL, respectively. Three audiometric contours and associated loudness discomfort levels were used in the simulation. Findings indicated that the relationship between tolerances and the number of aids selected as optimally appropriate varied substantially as a function of audiometric configuration. Minimum gain and SSPL tolerance values of +/- 12 dB and +/- 4 dB, respectively, were required to provide a reasonable choice of instruments for a variety of such configurations. Further analyses shed light on the feasibility of using alternative stringency criteria and on the clinical utility of hearing aid selection using small clinic samples.

Audiometry↗
PubMed1987

Relationships among selected measures of single-channel cochlear implant performance.

Relationships among a number of pre- and postimplant variables measured in 20 adults implanted with a single-channel cochlear implant were examined through a variety of univariate and multivariate statistical techniques. A large number of variables were analyzed to yield information on the relationships between pre- and postimplant performance, and among a variety of postimplant measures. Variables included: age; etiology and nature of deafness; type of implant worn; pre- and postimplant warble tone and speech detection thresholds; postimplant performance on the Monosyllable-Trochee-Spondee (MTS) and Environmental Sounds tests; postimplant electrical thresholds, uncomfortable loudness levels, and dynamic range; I.Q. scores; and postimplant discourse tracking performance with and without the implant. The difference score on the discourse tracking task, representing the auditory advantage over performance with lipreading alone, related substantively to a combination of variables including type of unit worn (Sigma versus Alpha), nature of deafness (progressive versus sudden), and etiology (meningitis versus nonmeningitis). Additionally, MTS and Environmental Sounds test scores were found to relate to one another and to etiology and nature of deafness.

Adolescent↗
PubMed1986

Relative effects of low-frequency amplification on syllable recognition and speech quality.

A moderate-bandwidth master hearing aid was used to study the relationships among low-frequency response, syllable recognition scores, and perceived speech quality. As measured on KEMAR, this hearing aid provided true high-frequency emphasis in all conditions, with three degrees of relative low-frequency de-emphasis. Subjects were 12 listeners with gradually sloping sensorineural hearing loss bilaterally. Contrary to common expectations, increased low-frequency response yielded a substantial enhancement in speech quality under both quiet and babble conditions, as well as a modest improvement in syllable recognition in quiet. Furthermore, low-frequency amplification, as used in this study, resulted in no observable degradation in syllable recognition in the presence of multitalker babble. The findings have clinical implications in the evaluation and selection of hearing aids when optimization of speech quality is desired.

Acoustic Stimulation↗
PubMed1986

Cochlear implant candidate selection.

In recent years there has been an increased acceptance of the cochlear implant as an appropriate sensory aid for selected hearing-impaired individuals with profound losses. With the Food and Drug Administration's release of the 3M/House single channel cochlear implant on November 29, 1984 and the Nucleus 22-channel cochlear implant on October 31, 1985 it is anticipated that many new groups of otologists and audiologists will have direct involvement in this exciting new approach to the management of patients with profound hearing impairments. This report reviews our cochlear implant selection protocol for the severe to profound adult hearing-impaired population.

Adult↗
PubMed1986

Long-term intracochlear implantation in man.

Whether long-term intracochlear implantation and direct electrical stimulation of the acoustic nerve will induce intracochlear bone growth or cause further degeneration of a severely compromised auditory system is an important clinical consideration. Thin-section CT evaluations of the cochleas of six subjects who have used their cochlear implant devices on a daily basis for 3 or more years demonstrated no evidence of osteoneogenesis of the cochlea in the vicinity of the active electrode. No corrosion of the electrode or insulation material was noted on electron microscopy of an explanted electrode system. Electrical threshold and dynamic range measurements have remained stable or even improved during the period of observation. Performance measures using a variety of audiologic tests and speech-tracking scores have demonstrated stability of performance.

Adult↗
PubMed1985

Spondee recognition threshold as a function of set size.

Recognition thresholds for spondaic words were obtained in normal listeners under conditions of varying set size. Six sets of spondees were derived from the 36-word corpus of a Northwestern University recording of CID W-1 spondaic words. One of these sets represented the full list of 36 spondees, whereas the remaining five were comprised of 27, 18, 9, 6, and 3 spondees selected to be homogeneous in level and slope characteristics. Results revealed a systematic and reliable effect wherein mean threshold decreased from 19.1 dB SPL to 12.2 dB SPL as set size was reduced from 36 to 3 spondees. The data are consistent with past research on human information processing in that spondee recognition threshold increased linearly with the number of bits per stimulus.

Adolescent↗
PubMed1978

Measurement of attack-release times in compression hearing aids.

A system for measurement of attack-release times in hearing aids with automatic-gain-control circuitry is described, with a view toward implementing that portion of the ANSI S3.22-1976 Standard in which parameters for these measurements are specified. Signal generation is accomplished by using a phased-array loudspeaker arrangement designed to produce transient-free pulsed acoustic sinusoids. Output waveforms are captured by a commercial transient recorder, and are displayed in either an oscilloscopic or graphic mode. A specific means of calculating attack and release times is recommended whereby variously shaped output waveforms are amenable to the basic protocol outlined in the ANSI Standard.

Acoustics↗
PubMedDate not supplied

Quality judgments of hearing aid-processed speech and music by normal and otopathologic listeners.

Ten normal listeners and ten listeners with high-frequency sensorineural hearing loss were given a paired-comparison task designed to elicit relative quality preferences among hearing aids when male speech, female speech, and music were processed by five different instruments. Results revealed notably high intrasubject test-retest reliability within the two groups of listeners for the male speech condition and in normal listeners for the female speech condition. Preferences assigned for any one of the three stimuli were found to be statistically correlated with those assigned for each of the other two stimuli. Furthermore, preferences of the otopathologic listeners were statistically equivalent those yielded by the normal listeners. Within the separate groups of listeners, rankings derived from the preferences of individual subjects were highly related to those of the other subjects within the respective group, suggesting the lack of a hearing aid-listener interaction. The relationship between preferences and "goodness" of selected electroacoustic characteristics, examined descriptively, was found to be equivocal. Overall results suggest that, while paired-comparison quality judgments may serve as an adequately reliable and adequately differentiating index of behavioral performance with hearing aids, incorporation of such a task within the traditional philosophy of hearing aid evaluation appears unjustifiable.

Acoustics↗
PubMedDate not supplied

Masking of spondees by interrupted noise in hearing-impaired listeners.

The effects of changing the duty cycle of an interrupted-broad band masker on the spondee thresholds of hearing-impaired subjects were explored. Two diagnostic groups of sensorineural hearing loss, presbycusics and cochlear otosclerotics, were investigated. The interruption rate of the masker was 10/sec, and its duty cycle was varied at 25% intervals. Thresholds also were obtained in continuous noise and in quiet. Results when compared with earlier data from normal listeners revealed that subjects with sensorineural impairment exhibited poorer performance in all instances, including the continuous noise condition, when mean masker levels were adjusted to comparable sound pressure levels. The overall pattern of masking was more similar for the normal and hearing-impaired groups when performance was equated in terms of the mean threshold shift each group experienced in continuous noise. Even under these circumstances, however, hearing-impaired subjects demostrated notably greater residual masking under the 25 and 50% noise-on conditions. A major determinant of speech reception in fluctuating noise backgrounds is the dependence of the pattern of masking upon the difference between an individual's masked threshold in continuous noise and his threshold in quiet, rather than upon the sound pressure level of the masker.

Acoustic Stimulation↗
PubMedDate not supplied

Listener-assessed intelligibility of hearing aid-processed speech.

The capacity of listeners to yield reliable and valid preferences for hearing aid-processed speech was evaluated by the method of paired comparisons. Discourse by a male talker with General American dialect was processed by five hearing aids under conditions of quiet and a background of multitalker babble. Hearing aid-processed Revised Central Institute for the Deaf Sentences spoken by the same male talker and embedded in the same multitalker background were used as stimuli in establishing criterion intelligibility performance. All stimuli were tape-recorded and delivered via monaural earphone to 90 normal listeners. Test-retest results revealed reliability coefficients of 0.94 and 0.65 on the paired-comparison condition in quiet and in babble, respectively. A low-positive relationship was observed between responses on the two subjective tasks. Essentially negligible correlations were found between subjective preferences on these individual conditions and performance on the sentence task. General conditions are hypothesized under which paired-comparison judgments of intelligibility might be expected to correspond favorably with objective performance.

Hearing Aids↗
PubMedDate not supplied

Decibel notation with correlated and uncorrelated signals.

Audiologists perform sound level measurements in a variety of settings. These measurements typically involve clinical audiometric calibration, specification of sound field levels in industrial environments, psychoacoustic experimentation, or specification of sound levels in hearing and test boxes or anechoic chambers. Any of these circumstances can present problem situations in which some form of signal combination is involved. Solutions of such problems require use of the concepts of average power and signal correlation, as they are related to decibel notation. These concepts are discussed in the present paper, and several examples that apply these concepts to specific measurement situations are presented.

Noise↗