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PubMed1989

The superiority of the Goodwin procedure over the traditional procedure in measuring the loudness level of tinnitus.

The results of two procedures for measuring the loudness level of tinnitus will be presented. The traditional procedure yielded significantly smaller loudness matches, when expressed in decibel sensation level (i.e., dB SL), than did the Goodwin procedure. The Goodwin procedure is more sensitive to pharmacologically induced changes in tinnitus loudness than is the traditional procedure. The Goodwin method correlates well with changes in patient's subjective rating of tinnitus severity. The Goodwin match has a larger reliability coefficient. Nonlinear correlation also indicates that the Goodwin procedure is superior to the traditional method.

Aminooxyacetic Acid↗
PubMed1990

Preliminary studies on the use of an ABR amplitude projection procedure for hearing aid selection.

Hearing aid selection in young nonverbal children is difficult and objective selection procedures are needed. Kiessling (Scand Audiol 1982;11:269-275; Arch Otorhinolaryngol 1983;238:233-240) has proposed an objective hearing aid selection method based on an unaided ABR amplitude projection procedure. However, Kiessling's ABR projection method is based on the assumption that ABR amplitude is directly related to the loudness of a signal--an assumption which has not been tested. This assumption was investigated in a group of ten normally hearing and three hearing-impaired listeners. The results indicated that ABR amplitude measures obtained in a single trial do not always correlate well with perceived loudness, but ABR amplitudes averaged over several trials do correlate well with estimates of perceived loudness. The hearing-impaired listeners then participated in a second phase of the investigation in which hearing aids chosen by the ABR projection procedure were compared with hearing aids chosen by more conventional methods. The results indicated that the projection procedure prescribed appropriate gain and compression characteristics for two of the three hearing-impaired listeners.

Adult↗
PubMed1991

Preferred hearing aid gain in everyday environments.

Thirty-three hearing-impaired individuals were each fitted with three hearing aids. The instruments conformed to three frequency-gain prescriptions, differing by a total of 8 dB/octave, with the middle prescription derived using the MSU version 3.0 procedure. The subjects were divided into three matched groups of eleven. Each group used the fitted hearing aids in one of three everyday listening environments representing quiet, reverberant, and noisy situations, respectively. In each listening environment, preferred hearing aid gain for conversationally produced speech was measured in each hearing aid condition for each subject. Preferred gain in daily listening situations was compared to prescribed gain. Results indicated that: (1) preferred gain averaged across all three environments was about equal to prescribed gain, (2) mean preferred gain in each separate environment was substantially different from the prescribed level, (3) volume control adjustments of about +/- 8 dB relative to the prescribed level would be necessary to accommodate the preferred gain settings of the typical hearing aid wearer in daily life. Guidelines are presented for establishing recommended volume control settings for hearing aid users who may be unable to set the volume control independently.

Acoustics↗
PubMed1991

Hearing aid benefit in everyday environments.

Hearing aid benefit was measured for three matched groups of eleven hearing-impaired subjects, each serving in one typical listening environment. Benefit was quantified in terms of improvement in intelligibility score for the Connected Speech Test. Each subject was individually fitted with three hearing aids, differing in nominal frequency response slope by a total of 8 dB/octave. Research questions centered on the amount of benefit typically realized in everyday environments and the interactions of this benefit with frequency response and/or visual cues. Results revealed: (1) mean benefit in a living-room type setting was about 24% and significantly greater than in a reverberant setting (7%) and a noisy setting (-1%); (2) despite the relatively large mean difference in benefit between the reverberant and noisy environments, the difference was not statistically significant (p greater than 0.05); (3) the addition of visual cues did not change hearing aid benefit in any tested environment; (4) there was no significant overall trend for any of the three different frequency-response slopes to give superior benefit in any environment; (5) 76% of the subjects achieved significantly different benefit (p less than 0.05) in at least one hearing aid condition when data were considered on an individual basis; and (6) articulation indices in the aided conditions did not successfully predict the observed within-subject benefit differences. Benefit was significantly related to speech reception threshold in the living-room environment. However, in the less favorable environments, benefit and hearing loss were not related despite the fact that benefit varied considerably across subjects.

Acoustics↗
PubMed1991

Probe tube microphone measures of loudness discomfort levels in children.

Loudness discomfort levels (LDLs) have been advocated as a means for selecting the SSPL90 setting of an individual's hearing aid. Kawell, Kopun, and Stelmachowicz (Ear Hear 1988; 9: 133-136) recently developed a procedure to measure LDLs in children. Several procedural cautions, involving the hearing aid stimulus delivery and sound field calibration, have been noted with this method. As a means of overcoming these problems, a new method utilizing insert earphone derived stimuli delivered to a child's ear-mold with probe tube microphone monitoring of real-ear sound pressure level was explored. Twenty children, aged 7 to 14 years, served as subjects. The advantage of the present method lies in the procedural conveniences and the ability to compare real-ear audiometric measures and hearing aid performance.

Adolescent↗
PubMed1991

Thresholds of discomfort in young children.

Procedures for obtaining thresholds of discomfort from young children are almost nonexistent. This is likely due to the problems encountered in finding a task that they can easily perform. The purpose of this project was to design and test a procedure appropriate to the cognitive and language abilities of 4- to 5-yr-old hearing-impaired children. Data obtained from normally hearing subjects indicate that the procedure can be used with children whose mental ages are at or above 5 yr.

Child Development↗
PubMed1991

Hearing aid gain for loudness-density normalization in cochlear hearing losses with impaired frequency resolution.

A theoretical criterion for preliminary prescription of hearing aid gain and frequency response was formulated on the basis of Zwicker's loudness model, modified for impaired auditory frequency resolution in cochlear hearing losses. The procedure was designed to restore normal relative loudness contributions from each frequency band of input speech. Prescribed frequency responses had less steep bass cut than recommended by either the Prescription of Gain/Output or the National Acoustic Laboratories' procedures, regardless of various model assumptions. Prescribed overall gain depended on the loudness growth assumed in the model. In cases where auditory filters are wider than normal and loudness recruitment is complete, the procedure yielded a nonlinear relation between hearing aid gain and hearing loss: Required insertion gain (in dB) was 25 to 30% of hearing threshold loss (in dB HL) for mild to moderate losses, but this percentage increased for more severe impairments. For cases with incomplete loudness recruitment, the model prescribed that insertion gain should be 40 to 50% of hearing threshold loss for a wide range of impairments.

Amplifiers, Electronic↗
PubMed1991

Sound quality and speech reception for prescribed hearing aid frequency responses.

Four different prescriptions of hearing aid insertion gain versus frequency were validated with a group of 26 moderately hearing-impaired, elderly hearing aid users. Three prescriptions were based on calculating the loudness and articulation index (AI) for aided speech, and ranged from a frequency response with moderate high-frequency emphasis, restoring normal loudness for speech peaks, to a response with the greatest high-frequency emphasis, maximizing the AI. The fourth prescription was a well-established formula of the half-gain type. The frequency responses were evaluated by paired comparison ratings of the pleasantness and intelligibility of speech in noise, and by speech identification tests in noise. The subjects rated the flattest response as significantly more pleasant than the other responses, and significantly more intelligible than the prescription with maximal high-frequency emphasis. There were no detectable differences in signal/noise ratios required for 50% speech identification. These results indicate that a prescription that restores normal loudness for speech peaks in each critical band is probably more easily accepted than either a procedure which is intended to make all speech bands equally loud, or a prescription which maximizes the AI.

Aged↗
PubMed1991

Loudness judgment procedures for evaluating hearing aid preselection decisions for severely and profoundly hearing-impaired listeners.

Hearing aid fitting involves a two-phase process of preselection and evaluation (Seewald RC and Ross M. Amplification for the Hearing Impaired 1988:213-271). The purpose of the present study was to examine alternative procedures that clinicians might use in the evaluation phase to verify the adequacy of hearing aid preselection decisions for severely and profoundly hearing-impaired listeners. Bekesy tracking, loudness rating, and conventional bracketing procedures were used to determine threshold, most comfortable listening level, and uncomfortable listening level for 10 hearing-impaired young adults. Stimuli were pulsed pure tones of 500, 1000, and 2000 Hz and filtered words. Means and standard deviations of most comfortable listening levels and uncomfortable listening levels derived from loudness judgments of the 10 subjects showed only nominal differences across procedures. However, correlation analysis (Pearson r) indicated that individuals responded to the three procedures in varying ways, producing different loudness judgments and overall dynamic ranges. Thus, test procedure may influence the clinician's final evaluation of a preselected hearing aid. Initial work suggests that closed-set response categories such as loudness rating can limit measurement variability and potentially guide the clinician's evaluation of hearing aid preselection decisions.

Adult↗
PubMed1991

Evaluation and assessment of FM systems.

In the past, frequency modulated (FM) systems were recommended for use only in educational settings for children with severe or profound hearing losses. Recent studies, however, have suggested that FM systems may be appropriate in nonacademic settings and also may benefit children with minimal hearing loss. In addition to the more widespread application of FM use, advances in amplification technology have provided audiologists with a variety of devices and coupling options, resulting in more variables to evaluate in the fitting process. There are three commonly used methods of evaluating FM systems: functional gain measures, probe tube microphone measures, and coupler measures. This paper is intended to provide the audiologist working with FM systems with an overview of the complexities involved in selecting and setting FM systems and the benefits and limitations of each evaluation method. Each evaluation method is examined in view of how well it answers three basic questions related to frequency response, maximum output, and distortion in FM systems. Finally, other issues which may impact on the selection of an FM system for a given individual are discussed.

Acoustics↗
PubMed1991

Allowing for real ear venting effects when selecting the coupler gain of hearing aids.

Vents in hearing aids have two major effects on the insertion gain of a hearing aid: they let low-frequency sound in without amplification, and they reduce the low-frequency gain of sound transmitted through the hearing aid. Their net effect on low-frequency gain can thus be either negative or positive. This paper shows how to allow for both of these effects. One of the results is that for many hearing-impaired clients, there is a range of coupler gain curves which will result in the required insertion gain. The tables in this article are arranged to enable the user to specify a desired vent, and then determine the allowable range of coupler gains that will achieve a desired insertion gain to within a specified tolerance. The results of various studies comparing coupler gain and insertion gain are also compared and combined. The calculation method outlined in this paper can predict low-frequency real ear insertion gain for the individual subject with a prediction accuracy (root-mean-square-error) of 3.6 dB.

Ear↗
PubMed1992

Real ear attenuation at threshold for three audiometric headphone devices: implications for maximum permissible ambient noise level standards.

Attenuation measurements were made using the ANSI S12.6-1984 protocol on a standard Telephonics headset with TDH-50P earphones and Model 51 cushions, Amplivox Audiocups headphone enclosures, and Peltor AudioMate headphone enclosures. Each of the enclosures housed Telephonics TDH-50P earphones with Model 51 cushions. The mean attenuation values obtained were compared with those previously reported, and reasons for discrepancies were analyzed. Pure-tone threshold shifts in background noise complying with ANSI S3.1-1977 and Occupational Safety and Health Administration (1983) maximum permissible ambient noise level standards were estimated on the basis of the attenuation values for each headphone device, and the adequacy of these current standards for accurate pure-tone threshold assessment was considered. The results indicated that Model 51 cushions alone are insufficient to attenuate the ambient noise levels permitted under ANSI S3.1-1977, and even the utilization of noise-excluding headphone enclosures does not reduce the background noise levels permitted under the Occupational Safety and Health Administration (1983) to a sufficient degree to permit testing down to 0 dB HL.

Adult↗
PubMed1992

Evaluation of a dual-channel full dynamic range compression system for people with sensorineural hearing loss.

This article describes an evaluation of an in the ear hearing aid, which applies fast-acting full dynamic range compression independently in two frequency bands. This can compensate for the loudness recruitment typically associated with sensorineural hearing loss. The crossover frequency between the two bands and the gain and compression ratio in each band are programmable to suit the individual patient. Twenty subjects with moderate sensorineural hearing loss were tested in a counterbalanced order using the aid programmed as a linear amplifier (condition L) and as a two-band compressor (condition C). All subjects were fitted binaurally. Subjects were also tested without hearing aids (condition U) and using the hearing aids that they normally wore (condition Own). Speech intelligibility was measured in quiet at three sound levels (50, 65, and 80 dB SPL), and speech reception thresholds (SRTs) in 12-talker babble were measured under monaurally and binaurally aided conditions, with the speech and babble both coincident and spatially separated. In condition C, speech intelligibility in quiet was high at all sound levels. Speech intelligibility at the two lower levels decreased in condition L, and decreased still further in conditions Own and U. Condition C gave, on average, better speech intelligibility in babble (lower SRTs) than conditions L, Own, or U. The advantage of condition C over condition L varied across subjects and was correlated with the dynamic range for tones at high frequencies; small dynamic ranges were associated with greater benefit from compression. A significant advantage for binaural aiding was found both when the speech and noise were spatially separated and when they were coincident. The binaural advantage was similar for the C and L conditions, indicating that the independent compression at the two ears did not adversely affect the use of binaural cues. Questionnaires on the subjects' experiences with the aids in everyday life indicated that they generally preferred condition C over condition L.

Adult↗
PubMed1993

Loudness balance between acoustic and electric stimulation by a patient with a multichannel cochlear implant.

Estimates of loudness balance were obtained for acoustically and electrically presented 250 Hz sine signals from a patient who uses the Ineraid multichannel cochlear implant. Acoustic and electric loudness matching was possible because the patient evidenced a 25 dB HL threshold at 250 Hz in his nonimplanted ear. The level of the electrical stimulus in microamperes required for a balance of loudness grew linearly with equal increments in decibels for the acoustic stimulus. These data, in concert with the very limited data from previous studies, provide a rationale for using a logarithmic transformation of acoustic to electric intensity in signal processors for cochlear implants.

Acoustic Stimulation↗
PubMed1994

The relationship between electrical acoustic reflex thresholds and behavioral comfort levels in children and adult cochlear implant patients.

The accuracy with which behavioral comfort levels could be predicted by the electrically elicited acoustic reflex threshold (EART) was examined in 35 Nucleus Cochlear Implant patients (16 adults and 19 children). EARTs were obtained by stimulating bipolar pairs of electrodes through the Nucleus Diagnostic Programming System and monitoring the change in middle ear admittance in the ear contralateral to the implanted ear. EARTs were successfully elicited in 24 patients. EARTs differed from behavioral comfort levels by a mean of 19.4 stimulus level units for adults and 9.6 stimulus level units for children. While EARTs were found to be acceptably close to behavioral comfort levels in four adults and eight children, EARTs significantly overestimated or underestimated comfort levels in the rest. The results of this study suggested that while the EART does not accurately predict comfort levels in all cases, it may provide valuable information regarding levels which should not be exceeded when programming the cochlear implant. Cautious use of information available from the EART may prove useful for programming the cochlear implant in children or adults who are unable to make reliable psychophysical judgments.

Acoustic Stimulation↗
PubMed1994

Simultaneous measurement of tinnitus pitch and loudness.

OBJECTIVE: Simultaneous measures of the frequency and level of a pure tone matching the predominant pitch and loudness of tinnitus were obtained using four interleaved staircases. DESIGN: Two staircases in a forced-choice procedure tracked two frequencies, one higher and one lower than the predominant pitch of the tinnitus, while two staircases tracked two levels, one louder and one softer than the tinnitus. RESULTS: The standard deviation of the pitch matches to tinnitus using the forced-choice procedure with four staircases (4SFC) exceeded that from a double staircase (2SFC) task in which the level of the matching tone was fixed, whereas the 2SFC and 4SFC tasks had similar SDs for loudness matches to tinnitus when the frequency of the matching tone was fixed and for matches to the pitch or loudness of external tones. As the level of the tone matching the tinnitus pitch in the 4SFC task increased relative to that of the 2SFC task, so did its frequency. CONCLUSION: These data may be interpreted as indicating that tinnitus is a fluctuant signal, and that matches of pure tones to tinnitus are not single-valued.

Acoustic Stimulation↗
PubMed1995

Use of test-retest measures to evaluate performance stability in adults with cochlear implants.

OBJECTIVE: This study was designed to evaluate performance stability with test-retest measures of electrical thresholds, electrical maximum acceptable loudness levels, sound-field thresholds, and audition-only speech tests. The hypothesis was that the standard error of measurement differs from one individual to another for each test, and therefore test-retest measures need to be obtained from each subject. DESIGN: Test-retest data were obtained in three sets. For the first two sets, data were obtained over 4 successive weeks to determine day-to-day variability. The third set was obtained on 2 successive days, 2 to 10 months later at each subject's annual evaluation. The seven subjects were recipients of the Nucleus cochlear implant and used the Mini Speech Processor at least one year. They were selected because they were available for research testing. RESULTS: The ranges of electrical thresholds and maximum acceptable loudness levels obtained from each subject during the first two sets were substantially larger on some electrodes than on others. Between set 1 and set 2 for each subject, there were significant differences between thresholds and between maximum acceptable loudness levels on some electrodes. For thresholds as well as maximum acceptable loudness levels, the standard error of measurement across the three sets and 10 electrodes differed among subjects. The group standard error of measurement for sound-field thresholds was small (2 dB). The group standard error of measurement for the NU-6 word test scored according to phonemes (2.75%) was less than half that for the vowel (6.06%) and consonant (5.67%) tests. The standard error of measurement for each speech test differed among subjects. CONCLUSIONS: The standard error of measurement for thresholds as well as maximum acceptable loudness levels varies among electrodes in the same subject and among subjects across electrodes. The standard error of measurement also varies among speech tests for the group as well as among subjects for each speech test. There is little variation in test-retest measures of sound-field thresholds among subjects. These results suggest the clinical importance of obtaining test-retest measures for evaluating the stability of electrical thresholds, electrical maximum acceptable loudness levels, and speech tests.

Adult↗
PubMed1996

Test-retest reliability of loudness scaling.

OBJECTIVE: Establish the test-retest reliability of loudness scaling using a bounded category rating method. DESIGN: The individual loudness functions were investigated in three groups of listeners: seven normal-hearing listeners age 18 to 35 yr, five normal-hearing listeners aged 57 to 84 yr, and five listeners aged 54 to 82 yr with bilateral sloping sensorineural hearing loss. Test-retest reliability was investigated by determining the intralistener, between-session standard deviation. RESULTS: The pattern of test-retest reliability was similar across all three groups. It improved as the intensity of the stimulus increased: 7 dB at the first quartile of the loudness function, and 3 dB at the third quartile. Two to four runs of the task appear to be sufficient to obtain a stable loudness function, and it was shown that an exponential function provided a better goodness of fit than a linear function (r2: 0.99 compared with 0.94). CONCLUSIONS: Loudness scaling is a longer test than most conventional suprathreshold measures and requires special equipment. However, it has good test-retest reliability and provides more information on the loudness function that might be useful in the fitting of nonlinear hearing aids. The data show that an exponential function provides a good fit to the loudness growth data, and should probably be incorporated into fitting algorithms associated with loudness scaling.

Adolescent↗