Comparison of Hearing-Aid Gain Using Functional, Coupler, and Probe-Tube Measurements

1986 ◽  
Vol 29 (2) ◽  
pp. 218-226 ◽  
Author(s):  
David Mason ◽  
Gerald R. Popelka
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Sound Field ◽  
Average Difference ◽  
Ear Canal ◽  
Tube System ◽  
Acoustic Characteristics ◽  
Standard Deviations ◽  
Functional Gain

Measurements of functional gain were compared first to coupler gain for 57 subjects using one of three hearing aid—earmold combinations and second to probe-tube gain for 12 subjects using in-the-ear hearing aids. The average difference between functional and coupler gain plotted as a function of frequency yielded results that were similar to previous reports, with the greatest effects occurring at 3000 and 4000 Hz. Significant differences were seen among hearing aid—earmold combinations at 3000, 4000, and 6000 Hz. Standard deviations for measurements between 750 and 2000 Hz were less than 5 dB and could be explained by variability of functional gain measures associated with test—retest variability of thresholds measured in a sound field. Below 750 Hz and above 2000 Hz, standard deviations exceeded 5 dB. The greater variability may be explained by differences in earmold venting, acoustic characteristics of the ear canal, and stimuli used to measure functional and coupler gain. Neither room nor hearing-aid noise appeared to affect the results significantly. When functional gain was compared to insertion gain measured with a probe-tube system, the average difference across frequencies was less than 1 dB. The variability of the differences at all frequencies, with the exception of 6000 Hz, was within the range reported for functional gain measurements. It was concluded that functional gain can be accurately estimated using probe-tube measurements.

Probe-Determined Hearing-Aid Gain Compared to Functional and Coupler Gains

1985 ◽  
Vol 28 (3) ◽  
pp. 394-404 ◽  
Author(s):  
Jan Zemplenyi ◽  
Donald Dirks ◽  
Samuel Gilman
Keyword(s):  
Hearing Loss ◽  
Individual Variation ◽  
Optical Method ◽  
Hearing Aid ◽  
Sound Field ◽  
Operating Microscope ◽  
Average Difference ◽  
Ear Canal ◽  
The Individual ◽  
Functional Gain

In this investigation, hearing-aid gain as measured by a probe-earmold system was compared with gain determined from couplers (HA-2 coupler and ear simulator) and functional-gain measurements. Fifteen subjects with moderate sensorineural hearing loss were tested under aided and unaided conditions in the sound field. In order to determine the effect of the occluded ear canal length on these results, an optical method was developed using an operating microscope to measure the length of the individual subject's occluded ear canal. The results indicate that gain, as measured by the probe-earmold system, corrected for effects of occluded ear canal length, agrees closely with functional and ear-simulator gain through 4.0 kHz. At the frequencies of 5.0 and 6.0 kHz the probe-earmold system underestimated gain particularly when compared to measurements conducted with the ear simulator. Other comparisons were also made between gain measured in a HA-2 coupler and functional gain. The average differences between these measurements of gain agree with several previous investigations, but individual variation around the average difference was smaller than previously reported.

Maximum Real-Ear Gain of In-the-Ear Hearing Aids

1991 ◽  
Vol 34 (2) ◽  
pp. 351-359 ◽  
Author(s):  
Faye N. Erickson ◽  
Dianne J. Van Tasell
Keyword(s):  
Individual Differences ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Hearing Impaired ◽  
Volume Control ◽  
Ear Canal ◽  
Shell Size ◽  
Maximum Gain ◽  
Functional Gain

Three hearing aid manufacturers provided custom full-shell in-the-ear hearing aids for each of 3 hearing-impaired subjects. Each manufacturer was instructed that the hearing aids should provide the maximum possible acoustic gain within the limits of hearing aid shell size and available components. Coupler gain, insertion gain, and functional gain were measured for each hearing aid. Gain measures were made with the volume control at either the full-on setting or the highest setting possible before the onset of acoustical feedback. Full-on coupler gain curves were similar across all nine hearing aids. Individual differences in concha/ear canal size and in the fit of the hearing aids produced substantial variance in insertion gain across hearing aids. Peak insertion gain varied from 41 to 58 dB. If 10 dB reserve gain is allowed, the range of estimated peak use gain from these maximum-gain in-the-ear hearing aids is 31–48 dB.

An Alternate Method for Determining Functional Gain of Hearing Aids

1984 ◽  
Vol 27 (4) ◽  
pp. 627-633 ◽  
Author(s):  
Diane Rines ◽  
Patricia G. Stelmachowicz ◽  
Michael P. Gorga
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Sound Field ◽  
Normal Hearing ◽  
Acoustic Reflex ◽  
Behavioral Threshold ◽  
Hearing Sensitivity ◽  
Behavioral Thresholds ◽  
Acoustic Reflex Threshold ◽  
Functional Gain

The functional gain of a hearing aid typically is determined by comparing aided and unaided behavioral thresholds. With this method, however, true gain may be underestimated in frequency regions of normal or near-normal hearing sensitivity (i.e., in cases of sloping, rising, or trough-shaped audiograms). Internal hearing-aid noise and/or amplified room noise imposes a lower limit on obtainable aided thresholds. In these cases, comparing aided and unaided acoustic-reflex thresholds may be a valuable clinical alternative to traditional means of determining real-ear gain. This study compared sound-field behavioral threshold and acoustic-reflex threshold estimates of functional gain for individuals with a variety of audiometric configurations. The sound-field behavioral threshold measurements were found to underestimate functional gain if unaided thresholds approached the normal hearing range. In regions of greater hearing loss, behavioral and acoustic-reflex estimates of functional gain were in good agreement.

Body-Baffle and Real-Ear Effects in the Selection of Hearing Aids for Deaf Children

1973 ◽  
Vol 38 (2) ◽  
pp. 224-231 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Deaf Child ◽  
Sound Field ◽  
Deaf Children ◽  
Ear Canal ◽  
Body Type ◽  
Acoustic Output ◽  
Selection Of

A difference between expected and obtained results in hearing-aid selection often can be explained on a physical basis alone. For example, the frequency response of a hearing aid typically is obtained by suspending the instrument in a free sound field and measuring the acoustic output of the receiver in a standard 2-cc coupler. However, when a body-type hearing aid is used by a deaf child, it normally is worn on his chest, and its receiver is coupled to an earmold in his ear canal. Under these conditions, the acoustic input to the hearing-aid microphone and the acoustic output of the receiver will differ from that measured in the laboratory. Because the dynamic range of sensitivity of profoundly deaf children typically is small, a neglected 5–10 dB of amplification can be critical in the selection of hearing aids. A clinical procedure is proposed by which the output of a hearing aid can be matched more accurately to the sensory capacities of an impaired ear. This method defines both thresholds and hearing-aid output in terms of sound pressures generated in a 2-cc coupler and considers only the specific body-baffle and real-ear effects that are produced by the patient himself.

The Reliability of Functional Gain

1990 ◽  
Vol 55 (2) ◽  
pp. 193-197 ◽  
Author(s):  
Larry E. Humes ◽  
Elizabeth U. Kirn
Keyword(s):  
Hearing Aids ◽  
Sound Field ◽  
Hearing Impaired ◽  
Retest Reliability ◽  
Standard Deviations ◽  
Test Retest Reliability ◽  
Functional Gain

This study examined the test-retest reliability of unaided and aided sound-field thresholds and the functional gain values derived from these measurements. Sound-field warble-tone thresholds were obtained at 250, 1000, and 4000 Hz from 24 hearing-impaired listeners with and without their hearing aids. Test-retest standard deviations were significantly larger for functional gain than for unaided thresholds, but only slightly and nonsignificantly larger than for aided thresholds. The variability of functional-gain measures is discussed in relation to measures of insertion gain obtained with probe-tube microphones.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

Modified Earpieces and CROS for High Frequency Hearing Losses

1968 ◽  
Vol 11 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Elizabeth Dodds ◽  
Earl Harford
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Field ◽  
Intensity Level ◽  
Test Results ◽  
High Frequency Hearing Loss ◽  
Increased Sensitivity ◽  
Difficult Cases

Persons with a high frequency hearing loss are difficult cases for whom to find suitable amplification. We have experienced some success with this problem in our Hearing Clinics using a specially designed earmold with a hearing aid. Thirty-five cases with high frequency hearing losses were selected from our clinical files for analysis of test results using standard, vented, and open earpieces. A statistical analysis of test results revealed that PB scores in sound field, using an average conversational intensity level (70 dB SPL), were enhanced when utilizing any one of the three earmolds. This result was due undoubtedly to increased sensitivity provided by the hearing aid. Only the open earmold used with a CROS hearing aid resulted in a significant improvement in discrimination when compared with the group’s unaided PB score under earphones or when comparing inter-earmold scores. These findings suggest that the inclusion of the open earmold with a CROS aid in the audiologist’s armamentarium should increase his flexibility in selecting hearing aids for persons with a high frequency hearing loss.

Noise Exposure Associated With Hearing Aid Use in Industry

1996 ◽  
Vol 39 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Thomas G. Dolan ◽  
James F. Maurer
Keyword(s):  
Hearing Aids ◽  
Noise Exposure ◽  
Hearing Aid ◽  
Sound Field ◽  
High Gain ◽  
Sound Level ◽  
Weighted Averages ◽  
Hearing Aid Use ◽  
Listening Environments ◽  
Level Meter

Although noise may be innocuous in many vocational environments, there is a growing concern in industry that it can reach hazardous levels when amplified by hearing aids. This study examined the daily noise exposures associated with hearing aid use in industry. This was done by both laboratory and site measurements in which hearing aids were coupled to the microphone of an integrating sound level meter or dosimeter. The former method involved the use of recorded railroad and manufacturing noise and a Bruel and Kjaer 4128 Head and Torso simulator. In the latter procedure, a worker wore one of three hearing aids coupled to a dosimeter during 8-hour shifts in a manufacturing plant. Both methods demonstrated that even when amplified by mild-gain hearing aids, noise exposures rose from time-weighted averages near 80 dBA to well above the OSHA maximum of 90 dBA. The OSHA maximum was also exceeded when moderate and high gain instruments were worn in non-occupational listening environments. The results suggest that current OSHA regulations that limit noise exposure in sound field are inappropriate for hearing aid users.

scholarly journals The use of speech sentence audiometry in a free sound field

2020 ◽  
Vol 5 (1) ◽  
pp. 36-39
Author(s):  
Mariya Yu. Boboshko ◽  
Irina P. Berdnikova ◽  
Natalya V. Maltzeva
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Normative Data ◽  
Hearing Aid ◽  
Sound Field ◽  
Normal Hearing ◽  
Significant Difference ◽  
Hearing Aid Benefit

Objectives -to determine the normative data of sentence speech intelligibility in a free sound field and to estimate the applicability of the Russian Matrix Sentence test (RuMatrix) for assessment of the hearing aid fitting benefit. Material and methods. 10 people with normal hearing and 28 users of hearing aids with moderate to severe sensorineural hearing loss were involved in the study. RuMatrix test both in quiet and in noise was performed in a free sound field. All patients filled in the COSI questionnaire. Results. The hearing impaired patients were divided into two subgroups: the 1st with high and the 2nd with low hearing aid benefit, according to the COSI questionnaire. In the 1st subgroup, the threshold for the sentence intelligibility in quiet was 34.9 ± 6.4 dB SPL, and in noise -3.3 ± 1.4 dB SNR, in the 2nd subgroup 41.7 ± 11.5 dB SPL and 0.15 ± 3.45 dB SNR, respectively. The significant difference between the data of both subgroups and the norm was registered (p

scholarly journals Assessment of Hearing Aid Benefit Using Patient-Reported Outcomes and Audiologic Measures

2020 ◽  
Vol 25 (4) ◽  
pp. 215-223
Author(s):  
James R. Dornhoffer ◽  
Ted A. Meyer ◽  
Judy R. Dubno ◽  
Theodore R. McRackan
Keyword(s):  
Hearing Aids ◽  
Patient Reported Outcomes ◽  
Hearing Aid ◽  
Sound Field ◽  
Patient Reported Outcome ◽  
Middle Ear Implant ◽  
Patient Reported ◽  
The Difference ◽  
Patient Reported Measures ◽  
Hearing Aid Benefit

Purpose: To determine the contributions to hearing aid benefit of patient-reported outcomes and audiologic measures. Methods: Independent review was conducted on audiologic and patient-reported outcomes of hearing aid benefit collected in the course of a middle ear implant FDA clinical trial. Unaided and aided data were extracted from the preoperative profiles of 95 experienced hearing aid users, and the relationships between a patient-reported outcome and audiologic measures were assessed. The following data were extracted: unaided and aided pure-tone or warble-tone thresholds (PTA), word recognition in quiet (NU-6), Speech Perception in Noise (low-/high-context SPIN), and patient-reported benefit (Abbreviated Profile of Hearing Aid Benefit, APHAB). Hearing aid benefit was defined as the difference in thresholds or scores between unaided and aided conditions, as measured in the sound field. Correlations were computed among audiologic measures and global APHAB and subscale scores of hearing aid benefit. Results: Significant improvements in all audiologic measures and APHAB scores were observed comparing unaided to aided listening (all p < 0.001). However, correlations between audiologic and patient-reported measures of aided performance or hearing aid benefit were low-to-weak or absent. No significant correlations were found between aided audiologic measures (PTA, NU-6, SPIN) and any aided APHAB scores (all p > 0.0125), and significant relationships for hearing aid benefit were absent with only few exceptions. Hearing aid benefit defined by global APHAB using NU-6 and SPIN scores showed significant but weak positive correlations (r = 0.37, p < 0.001; r = 0.28, p = 0.005, respectively) and ease of communication APHAB subscale scores (r = 0.32, p < 0.001; r = 0.33, p = 0.001, respectively). Conclusion: Hearing aid benefit assessed with audiologic measures were poor predictors of patient-reported benefit. Thus, patient-reported outcomes may provide a unique assessment of patient-perceived benefit from hearing aids, which can be used to direct hearing aid programming, training, or recommendations of alternative hearing services.

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