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Biomedical subjects

J L Punch

Publications and source records attributed to J L Punch.

29 records · Page 2Linked to original sources
PubMed1982

Tournament strategies in hearing aid selection.

Recently, the elimination tournament has been proposed as an approach to hearing aid selection. In the present study the effects of seeding on the reliability, clinical utility, and validity of the single and double elimination tournament as methods for selecting hearing aids were examined. In an earlier study of round robin tournaments, 12 hearing-impaired subjects were asked to make paired-comparison intelligibility judgments of all possible pairings of eight relatively homogeneous hearing aids. The present study employed these data in a computer-aided simulation of single and double elimination tournaments based on all possible seedings of the eight aids. The results indicated that while group performance was reliable and correlated well with nonsense-syllable identification, the distribution of tournament winners for individual listeners was unreliable and highly dependent on the effects of seeding. These findings were due in part, however, to the similarity of the intelligibility characteristics of the aids employed. Further investigation of the elimination tournament as a method for hearing aid selection is warranted.

Consumer Behavior↗
PubMed1981

Pairwise listener preferences in hearing aid evaluation.

The relationships among pairwise judgments of the quality of connected discourse, pairwise judgments of the relative intelligibility of discourse, and measured intelligibility on a nonsense-syllable test were evaluated under identical conditions of primary talker and competitive babble. Stimuli were processed by eight hearing aids and presented in a repeated-measures design to 12 listeners with sensorineural hearing loss. Results revealed moderately high test-retest reliability for all three experimental conditions. Overall, a noteworthy positive relationship was evident between relative intelligibility judgments and measured phonemic identification, although this relationship varied considerably among individual listeners. The correspondence between quality judgments and relative intelligibility judgments was substantially lower, while the relationship between judgments of quality and phonemic identification scores was negligible. Findings demonstrate the potential importance of instructional set in producing valid judgments of the relative intelligibility of aided speech. The determination of measurement error inherent in pairwise preference data is discussed from the viewpoint of a probabilistic model encompassing a binomial distribution. It is concluded that experimental optimization of the agreement between relative intelligibility judgments and measured intelligibility performance of individual listeners will be required before the pairwise comparison technique can be considered a viable alternative to traditional hearing aid evaluation procedures.

Aged↗
PubMed1980

Low-frequency response of hearing aids and judgments of aided speech quality.

Connected discourse was processed by a master hearing aid via two channels that were independently adjusted to seven discrete settings of low-cutoff frequency. Signals were tape-recorded and played back in a paired-comparison format to 12 listeners with gradually sloping sensorineural hearing loss, who selected the speech channel preferred for its sound quality. Four experimental trials were administered, each of which consisted of 21 randomized paired conditions. Results across the four trials revealed high intersubject and intrasubject response agreement. Listeners indicated strong and systematic preferences for speech reproduced by circuitry having progressively extended low-frequency emphasis. Findings confirm earlier experimental observations that hearing-impaired listeners are capable of making repeatable paired-comparison preference judgments of the quality of hearing-aid processed speech. Additionally, results demonstrate definitively that low-cutoff frequency is sufficiently robust to be regarded as the probable source of a potent perceptual basis for such judgments. The clinical implication is that hearing-impaired listeners can be expected to exhibit strong preferences for the quality of speech reproduced by hearing aids having relatively extended low-frequency response.

Acoustics↗
PubMed1980

Multidimensional scaling of quality judgments of speech signals processed by hearing aids.

Perceptual dimensions underlying similarity ratings and preference judgments of the quality of hearing-aid-processed speech were derived via multidimensional-scaling procedures, and were correlated with 15 indices of electroacustic performance to determine those electroacoustic characteristics contributing maximally to quality judgements. Connected discourse was tape recorded through 20 conventional hearing aids and presented in a paired-comparison paradigm to ten normal listeners for similarity ratings and quality preference judgments. Analysis of the group similarity matrices revealed only one definitive perceptual dimension, low-cutoff frequency, that was common to the listeners. In a three-dimensional INDSCAL solution, this electroacoustic factor correlated--0.87 with dimension 1. Listeners strongly preferred hearing aids with relatively low low-cutoff frequencies; dimension 1 correlated--0.76 with their preferences. The quality judgments of some listeners were found via KYST analysis to exhibit a multidimensional structure, with low-cutoff frequency remaining the most salient dimension. Secondary dimensions varied across these several listeners, and included response irregularity, equivalent input noise level, high-cutoff frequency, and intermodulation distortion. Thus, the data provided evidence that, while low-cutoff frequency dominates listener judgments a multidimensional model may underlie the perceptual strategies used by some listeners to form quality judgments of hearing-aid-processed speech.

Acoustics↗
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↗