A comparison of inter-aural attenuation with the Etymotic ER-3A insert earphone and the Telephonics TDH-39 supra-aural earphone.

One of the many reported advantages of the insert earphone over the supra-aural earphone is increased inter-aural attenuation (IA). Minimum values of IA determine the need for masking of the non-test ear in air-conduction audiometry. The aim of the present study was to measure inter-aural attenuation for the Etymotic Research ER-3A insert earphone (with deep and shallow insertion of the ear plug within the ear canal) and compare this with the supra-aural Telephonics TDH-39/MX41-AR earphone/cushion combination. Subjects were 18 adults ranging in age from 38 to 68 years (mean 50 years). Each subject had no hearing in one ear following translabyrinthine surgery for removal of an acoustic neuroma. The opposite ear had hearing thresholds better than 40 dB HL and an air-bone gap of less than 10 dB at any audiometric frequency. Pure tone air-conduction thresholds were obtained in the range 0.25-8 kHz. Deep insertion of the insert earphone was deemed to occur when the outside edge of the ear plug was flush with the entrance of the ear canal. Shallow insertion was deemed to occur when half of the ear plug (6 mm) was inside the entrance of the ear canal. IA was defined operationally as the difference between the good-ear and poor-ear not-masked air conduction threshold for a given audiometric frequency and earphone. The results show that the TDH-39/MX41-AR combination provides a median IA of approximately 60 dB with a lower limit of approximately 45 dB. Greater IA was obtained with the ER-3A insert earphone but this depended on the depth of insertion. With a deep insertion, the 1A values were some 15-20 dB greater than with the supra-aural earphone. Although frequency-specific IA values are provided, a simple rule of thumb is to apply masking to the non-test ear when the pure tone airconduction signal from the ER-3A insert earphone exceeds the bone conduction threshold of the non-test ear by 55 dB HL or more. If it is not possible to obtain a deep insertion depth this value should be reduced by 5 dB.     

Use of the 'real-ear to dial difference' to derive real-ear SPL from hearing level obtained with insert earphones

The electroacoustic characteristics of a hearing instrument are normally selected for individuals using data obtained during audiological assessment. The precise inter-relationship between the electroacoustic and audiometric variables is most readily appreciated when they have been measured at the same reference point, such as the tympanic membrane. However, it is not always possible to obtain the real-ear sound pressure level (SPL) directly if this is below the noise floor of the probe-tube microphone system or if the subject is unco-operative. The real-ear SPL may be derived by adding the subject's real-ear to dial difference (REDD) acoustic transform to the audiometer dial setting. The aim of the present study was to confirm the validity of the Audioscan RM500 to measure the REDD with the ER-3A insert earphone. A probe-tube microphone was used to measure the real-ear SPL and REDD from the right ears of 16 adult subjects ranging in age from 22 to 41 years (mean age 27 years). Measurements were made from 0.25 kHz to 6 kHz at a dial setting of 70 dB with an ER-3A insert earphone and two earmould configurations: the EAR-LINK foam ear-tip and the subjects' customized skeleton earmoulds. Mean REDD varied as a function of frequency but was typically approximately 12 dB with a standard deviation (SD) of +/- 1.7 dB and +/- 2.7 dB for the foam ear-tip and customized earmould, respectively. The mean test-retest difference of the REDD varied with frequency but was typically 0.5 dB (SD 1 dB). Over the frequency range 0.5-4 kHz, the derived values were found to be within 5 dB of the measured values in 95% of subjects when using the EAR-LINK foam ear-tip and within 4 dB when using the skeleton earmould. The individually measured REDD transform can be used in clinical practice to derive a valid estimate of real-ear SPL when it has not been possible to measure this directly.     

How does the sound pressure generated by circumaural, supra-aural, and insert earphones differ for adult and infant ears?

OBJECTIVE: To determine how the ear canal sound pressure levels generated by circumaural, supra-aural, and insert earphones differ when coupled to the normal adult and infant ear. DESIGN: The ratio between the sound pressure generated in an adult ear and an infant ear was calculated for three types of earphones: a circumaural earphone (Natus Medical, ALGO with Flexicoupler), a supra-aural earphone (Telephonics, TDH-49 with MXAR cushion), and an insert earphone placed in the ear canal (Etymoup and down arrow tic Research, ER-3A). The calculations are based on (1) previously published measurements of ear canal impedances in adult and infant (ages 1, 3, 6, 12, and 24 months) ears (Keefe et al., 1993, Acoustic Society of America, 94:2617-2638), (2) measurements of the Thévenin equivalent for each earphone configuration, and (3) acoustic models of the ear canal and external ear. RESULTS: Sound-pressure levels depend on the ear canal location at which they are measured. For pressures at the earphone: (1) Circumaural and supra-aural earphones produce changes between infant and adult ears that are less than 3 dB at all frequencies, and (2) insert earphones produce infant pressures that are up to 15 dB greater than adult pressures. For pressures at the tympanic membrane: (1) Circumaural and supra-aural earphones produce infant pressures that are within 2 dB of adult ears at frequencies below 2000 Hz and that are 5 to 7 dB smaller in infant ears than adult ears above 2000 Hz, and (2) insert earphones produce pressures that are 5 to 8 dB larger in infant ears than adult ears across all audiometric frequencies. CONCLUSIONS: Sound pressures generated by all earphone types (circumaural, supra-aural, and insert) depend on the dimensions of the ear canal and on the impedance of the ear at the tympanic membrane (e.g., infant versus adult). Specific conclusions depend on the location along the ear canal at which the changes between adult and infant ears are referenced (i.e., the earphone output location or the tympanic membrane). With circumaural and supra-aural earphones, the relatively large volume of air within the cuff of the earphone dominates the acoustic load that these earphones must drive, and differences in sound pressure generated in infant and adult ears are generally smaller than those with the insert earphone in which the changes in ear canal dimensions and impedance at the tympanic membrane have a bigger effect on the load the earphone must drive.     

Attenuation values for a supra-aural earphone for children and insert earphone for children and adults.

Earphone attenuation values were determined for 17 children (6-14 years old) using supra-aural (TDH-49P/Model 51 cushion) and insert earphones (E-A-Rtone 3A) terminated by an E-A-Rlink 3A (for normal size ear canals) or E-A-Rlink 3B (for small size ear canals) foam eartips, and for 10 adults having small ear canals using insert earphones and E-A-Rlink 3B foam eartips. The test signals were 1/3-octave bands of noise presented in a diffuse sound field (re: ANSI S12.6-1984). The supra-aural earphone attenuation values for the children were slightly higher (more attenuation) or similar to reported adult values, and always lower (less attenuation) compared with insert earphone/E-A-Rlink 3A (IE/3A) or 3B (IE/3B) values for both children and adults. The IE/3B attenuation values were similar between the children and adults and provided slightly more attenuation than the IE/3A. Overall, the results indicated that the ANSI S3.1-1991 maximum permissible ambient noise levels allowed in a test room for ears covered testing with a supra-aural earphone, which were determined using adult values, are appropriate for testing children. Future revisions of ANSI S3.1-1991 may include maximum permissible ambient noise levels for testing with insert earphones. The IE/3A and IE/3B attenuation values could be used for that purpose. In the meantime, because more attenuation was provided by the IE/3A and IE/3B, they can be used for testing both children and adults in higher ambient noise levels than specified in ANSI S3.1-1991.     

Test-retest reliability of in situ unaided thresholds in adults

PURPOSE: The purpose of this study was to examine test-retest reliability of in situ unaided thresholds measured using a handheld hearing aid programmer coupled to a hearing aid transducer in adults with normal hearing. METHOD: Randomized in situ thresholds at 4 octave frequencies were established in 1 ear of 43 adults twice using the Widex Diva SP3 device with the stimulus generated by and transduced through a Widex Diva SD-9 behind-the-ear hearing aid. Insert earphone tips were used in each of the measures to couple the hearing aid/transducer to the ear canal. RESULTS: Mean decibel differences between the test and retest thresholds were less than 1 dB at each frequency. Using an 80% statistical test criterion, results revealed test-retest reliability within 5 dB for all frequencies: 98% at 500 Hz, 100% at 1000 and 2000 Hz, and 93% at 4000 Hz. CONCLUSIONS: Test-retest reliability of in situ unaided thresholds using the SP3/SD-9 device is equivalent to that of currently accepted audiometric procedures.     

Interaural attenuation for tubephone insert earphones

Interaural attenuation of pure tone and speech signals was evaluated for a new audiometric insert earphone, the ER-3A tubephone, and a conventional TDH-49P supra-aural earphone in seven unilaterally deaf adult subjects. These results validate and extend the interaural attenuation data reported by the manufacturer of the ER-3A and his associates. At frequencies of 0.5 to 1 kHz, mean interaural attenuation for the deeply inserted ER-3A decreased from 94+ dB to 81 dB, with the lowest value for any subject, 75 dB. Interaural attenuation for speech approximated that of the 1 to 2 kHz frequency range. The ER-3A tubephone provides significantly greater acoustic isolation between the two ears in the low-mid frequency audiometric range than the conventional supra-aural earphone.     

TIP-300插入式耳机与TDH-50P耳罩式耳机的耳间衰减比较

目的 比较TIP-300插入式耳机耳间衰减(insert earphone interaural attenuation,IEIA)与TDH-50P耳罩式耳机耳间衰减(supra-aural earphone interaural attenuation,SELA)的差异，为TIP-300插入式耳机的临床应用提供参考依据。方法 利用GSI61临床听力计、TIP-300插入式耳机和TDH-50P耳罩式耳机，对一组单耳全聋而另一耳听力正常者35人(男13人，女22人)进行纯音气导的耳间衰减测试。结果 TIP-300插入式耳机与TDH-50P耳罩式耳机组间耳间衰减有显著性差异；其中TIP-300插入式耳机组内的某些频率之间耳间衰减也有显著性差异。结论 在低中频测听范围，TIP-300插入式耳机的耳间衰减比TDH-50P耳罩式耳机大。     

Insert earphones--a comparison of short-duration signals measured with an occluded ear simulator and a 2cc coupler

The responses of several insert earphones in the Etymotic 3A series were measured with the occluded ear simulator (IEC 60711) and the 2cc coupler (IEC 60126). Acoustic clicks following a 100 us rectangular voltage pulse were compared. The peak-to-peak equivalent sound pressure levels in the ear simulator were found to be 9.2 dB greater than those in the 2cc coupler. The difference was independent of type of earphone among those tested. Similar comparisons were made for tone pips (brief tones or tone bursts) and continuous tones. For a given drive voltage, differences in earphone output were almost the same as the corresponding differences in published RETSPLs for the occluded ear simulator and 2cc coupler (ISO 389-2).     

Earphones in extended high-frequency audiometry and ISO 389-5

Abstract

Objective: To determine common reference equivalent threshold sound pressure levels (RETSPL) for the earphones used in the extended high-frequency (EHF) range, as different earphones are commercially available, but there are not RETSPLs for each model. Design: Hearing threshold sound pressure levels were measured up to 20 kHz for the Sennheiser HDA 200 audiometric earphone, and were compared to the ISO 389-5 (2006) norm and other investigations using that earphone and different ones. Study sample: A total of 223 otologically-normal subjects (aged 5–25 years old) participated in the hearing determination. Results: The results are in good agreement with previous studies of hearing thresholds using the same and other earphones. Conclusions: The results of the present investigation are relevant for the international standard for the calibration of audiometric equipment in the 8 to 16 kHz frequency range, ISO 389-5. The data may be used for a future update of the RETSPL for circumaural and insert audiometric earphones.     

Compensated active noise cancellation earphone for audiometric screening tests in noisy environments

Abstract

Objective: This study investigated hearing screening tests by using a custom-designed compensated hybrid active noise cancellation (ANC) earphone and compared it with TDH39 and Audiocups audiometric earphones under conditions of quiet, 45?dB HL masking narrowband, wideband speech-shaped, and white noise.

Design: The hearing screening tests were conducted to characterise the shifts of screening results under noisy conditions, and real-ear attenuations at thresholds were assessed to quantify real-ear noise reduction performance.

Study sample: Twenty-four normal-hearing adults, aged 20–25?years, participated in this study.

Results: The ANC earphone exhibited significantly lower/better mean screening results than those of the TDH39 earphone at 250 and 500?Hz and those of the Audiocups earphone at 250?Hz under conditions of narrowband, speech-shaped, and white noise. Compared with the TDH39 earphone at 250 and 500?Hz, applying a hybrid ANC earphone reduced the shifts in screening results by 14.2 and 12.3?dB, respectively, under the narrowband noise condition.

Conclusion: This study demonstrated that the compensated hybrid ANC earphone provided lower shifts of screening results than the TDH39 and Audiocups earphones and that it was capable of screening at 250 and 500?Hz from 20?dB HL under 45?dB HL masking narrowband and wideband noise.     

Efficacy of earphones for 12- to 24-month-old children during visual reinforcement audiometry

Objective: Efficacy of insert and supra-aural earphones during visual reinforcement audiometry (VRA) was investigated for 12- to 24-month-old children. Design: VRA testing began in the soundfield and transitioned to either insert or supra-aural earphones. Audiologists recorded threshold estimates, participant behaviors, and an overall subjective rating of earphone acceptance. Study sample: One hundred and eighty-six 12- to 24-month-old children referred to the Department of Audiology at St. Louis Children’s Hospital for a variety of reasons. Results: Subjective ratings indicated high acceptance of insert earphones (84%) and supra-aural earphones (80%) despite negative behaviors. There was no significant difference in the number of threshold estimates based on earphone type for 12- to 17-month-old participants. Participants in the 18- to 24-month-old age group provided significantly more threshold estimates with insert earphones (mean?=?5.3 threshold estimates, SD?=?3.5) than with supra-aural earphones (mean?=?2.9 threshold estimates, SD?=?2.9). All seven participants who rejected earphone placement were successfully reconditioned for soundfield testing. Conclusions: Data support the use of insert earphones during VRA, especially with 18-to 24-month-old children, to obtain ear-specific information.     

Hearing aid coupler output level variability and coupler correction levels for insert earphones

HA coupler type SPLs were independently determined by two experimenters for five repeated measurements with and without replacement of two ER-3A and two EARTONE 3A insert earphones. Measurements were made using a B&K DB-0138 coupler configured as an HA-1, HA-2 earphone coupler and HA-2 earphone coupler with entrance through a rigid tube referred to as the DB-0138 coupler. The HA-1, HA-2, and DB-0138 SPLs were found to be very stable (+/- 0.2 dB) for all intra- and interexperimenter measurements for each insert earphone and coupler type from 125 to 8000 Hz. Averaged across both experimenters and all repeated measurements, the mean HA-1 and HA-2 coupler SPLs were similar for each insert earphone from 125 to 8000 Hz. The mean HA-1, HA-2, and DB-0138 coupler SPLs were similar for each insert earphone from 125 to 2000 Hz; however, from 3000 to 8000 Hz the DB-0138 coupler SPLs were higher than the HA-1 and HA-2 coupler SPLs for each insert earphone. This occurred because of the geometrical differences between the insert earphone to coupler connections and coupler types. The HA-1 minus DB-0138 and HA-2 minus DB-0138 coupler SPL differences, or coupler correction levels, could be explained by quarter-wave resonances and stepped-diameter tubing systems creating acoustic horn effects.     

Minimal response levels for visual reinforcement audiometry in infants

The aim of this study was to determine normative values for minimal response levels (MRLs) for normal-hearing young infants using insert earphone visual reinforcement audiometry (VRA). The subjects were 46 normally developing infants aged between 33 and 50 weeks who had hearing sensitivity assumed to be within normal limits and no evidence of middle ear dysfunction. VRA was carried out using insert earphones with warble tone stimuli, generated from an AC33 audiometer and calibrated to ISO 389-2 for insert earphones in adults. The frequencies assessed were 500 Hz, 1 kHz, 2 kHz and 4 kHz. In total, 102 MRLs were obtained, with an approximately equal number of MRLs per frequency. Mean MRLs for 500 Hz, 1 kHz, 2 kHz and 4kHz were 16 dB HL, 13 dB HL, 7 dB HL and 6 dB HL, respectively. Standard deviations were close to 6 dB for all frequencies. Mean MRLs at the lower frequencies were significantly greater than MRLs at the two higher frequencies. MRLs did not vary significantly with age. The results obtained from this study suggest significant infant adult differences when testing hearing using VRA with insert earphones, particularly at lower frequencies. Possible reasons for this and the clinical use of these normative values are discussed.     

Interaural attenuation using etymotic ER-3A insert earphones in auditory brain stem response testing

Click interaural attenuation (IA) was measured behaviorally and with the auditory brain stem response (ABR) in two unilaterally deaf adults with Etymotic ER-3A insert earphones, and TDH-39P and TDH-49P supraaural earphones. Stimulus crossover for each set of earphones was also determined with pure-tone audiometry. Pure-tone results agreed with previous research, showing that the ER-3A provided substantially greater IA than the supraaural earphones, particularly for low frequencies. For click stimuli, behavioral and ABR results revealed only modest, if any, improvement in IA with the ER-3A relative to the supraaural earphones. The results of this study suggest that while the ER-3A earphones provide a clear IA advantage for behavioral pure-tone audiometry, they do not eliminate the need for contralateral masking of click stimuli in ABR testing.     

The incidence of aminoglycoside antibiotic-induced hearing loss

The definition of ototoxicity in most clinical studies of aminoglycoside antibiotics is an increase in pure-tone threshold from a baseline audiogram greater than or equal to 15 dB at two or more frequencies, or greater than or equal to 20 dB at one or more frequencies. In this study, test-retest auditory threshold differences of this magnitude were found in a group of 20 normal volunteers who were not taking any known ototoxic drugs. Depending on which of the two criteria for ototoxicity are used, these data represent a 20% or 33% incidence of ototoxicity. We believe that many of the audiometric changes reported to represent aminoglycoside antibiotic ototoxicity may actually represent the normal test-retest variability of pure-tone audiometry. If this is true, the reported incidence of hearing loss due to aminoglycoside antibiotics may be exaggerated.     

The reproducibility of caloric tests of vestibular function in young and old subjects

The test-retest repeatability of the hot caloric response alone and of the hot and cold caloric responses combined, was evaluated in 29 subjects, over a 6-month period. The subjects were from two different age groups, 20-30 years (15 subjects) and 65-75 years (14 subjects). Intersubject variability was statistically significant in both age groups, though of greater magnitude in the older subjects. Once a vestibular caloric response baseline was established, for any given subject, there was reasonably reliable test-retest repeatability over time, in both age groups, with coefficients of reliability greater than 0.90.     

Mid-frequency sensorineural hearing loss: aetiology and prognosis

OBJECTIVES: An audiometric finding of mid-frequency sensorineural hearing loss (MFSNHL), or a U-shaped pattern, is uncommon. The objective of this study is to investigate the aetiology and prognostic significance of MFSNHL. DESIGN: Tertiary academic referral centre-based retrospective case review and review of audiograms to determine the prevalence of this audiometric finding. METHODS: Patients with a pure tone threshold average at 1, 2, and 4 kHz at least 10 dB greater than the average at 0.5 and 8 kHz were included in this study; 35 patients met these criteria. The mean age of the patients was 34.6 years old (range 4-71 years). Twelve patients (33 per cent) were under 18 years of age. Serial audiograms were obtained for 14 patients. The notes were reviewed for any pertinent otologic history, subsequent diagnoses, management and disease course. RESULTS: The prevalence of MFSNHL in this practice setting is less than 1 per cent. The average hearing threshold in the mid-frequencies was 44 dB, which was 17 dB and 20 dB lower than at 0.5 Hz and 8 kHz, respectively. The pure tone average (0.5, 1, 2 kHz) was 40 dB. Sixteen patients (44 per cent) required amplification. Of all patients, 22 had hereditary hearing loss, eight had idiopathic hearing loss, and five adults had vestibular schwannomas. CONCLUSIONS: MFSNHL is an infrequent audiometric finding. The great majority of these cases are of presumed hereditary or idiopathic aetiology, although 22 per cent of adults had vestibular schwannomas. This series presents the causes and prognosis of this audiometric pattern.     

A comparison of the variability in thresholds measured with insert and conventional supra-aural earphones

The purpose of this study was to evaluate the reliability and comparability of the commercially available insert earphone Etymotic Research ER-3A and the commonly available supra-aural TDH earphone. Thirteen subjects were tested five times with the ER-3A and five times with TDH-49P with MX-41/AR cushions. Threshold determinations were obtained utilizing a sweep-frequency audiometer in the range 0.25-8 kHz. The results showed that the reliability of the ER-3A earphone as measured by intra-individual variation, was comparable to that obtained with the TDH earphone. No evidence was found indicating an increased variability due to the positioning of the insert earphone's coupling device in the ear canal. Comparison of thresholds obtained with both devices indicated that the manufacturer's suggested correction values were appropriate.     

High-frequency (8 to 16 kHz) reference thresholds and intrasubject threshold variability relative to ototoxicity criteria using a Sennheiser HDA 200 earphone

OBJECTIVE: The first purpose of this study was to determine high-frequency (8 to 16 kHz) thresholds for standardizing reference equivalent threshold sound pressure levels (RETSPLs) for a Sennheiser HDA 200 earphone. The second and perhaps more important purpose of this study was to determine whether repeated high-frequency thresholds using a Sennheiser HDA 200 earphone had a lower intrasubject threshold variability than the ASHA 1994 significant threshold shift criteria for ototoxicity. DESIGN: High-frequency thresholds (8 to 16 kHz) were obtained for 100 (50 male, 50 female) normally hearing (0.25 to 8 kHz) young adults (mean age of 21.2 yr) in four separate test sessions using a Sennheiser HDA 200 earphone. RESULTS: The mean and median high-frequency thresholds were similar for each test session and increased as frequency increased. At each frequency, the high-frequency thresholds were not significantly (p > 0.05) different for gender, test ear, or test session. The median thresholds at each frequency were similar to the 1998 interim ISO RETSPLs; however, large standard deviations and wide threshold distributions indicated very high intersubject threshold variability, especially at 14 and 16 kHz. Threshold repeatability was determined by finding the threshold differences between each possible test session comparison (N = 6). About 98% of all of the threshold differences were within a clinically acceptable range of +/-10 dB from 8 to 14 kHz. The threshold differences between each subject's second, third, and fourth minus their first test session were also found to determine whether intrasubject threshold variability was less than the ASHA 1994 criteria for determining a significant threshold shift due to ototoxicity. The results indicated a false-positive rate of 0% for a threshold shift > or = 20 dB at any frequency and a false-positive rate of 2% for a threshold shift >10 dB at two consecutive frequencies. CONCLUSIONS: This study verified that the output of high-frequency audiometers at 0 dB HL using Sennheiser HDA 200 earphones should equal the 1998 interim ISO RETSPLs from 8 to 16 kHz. Further, because the differences between repeated thresholds were well within +/-10 dB and had an extremely low false-positive rate in reference to the ASHA 1994 criteria for a significant threshold shift due to ototoxicity, a Sennheiser HDA 200 earphone can be used for serial monitoring to determine whether significant high-frequency threshold shifts have occurred for patients receiving potentially ototoxic drug therapy.     

Three studies comparing performance of the ER-3A tubephone with the TDH-50P earphone

Three studies compared the performance of the ER-3A Tubephone insert earphone and the TDH-50P-MX41/AR supra-aural earphone. The three factors addressed were: threshold differences in children 7 to 10 yr old compared to adults, differences in real ear attenuation, and threshold differences in the presence of high background noise levels. The influence of insertion depth of the ER-3A Tubephone was also investigated. Findings showed no significant threshold differences between children and adults, significantly better real ear attenuation for the ER-3A Tubephone, and significantly better thresholds for the ER-3A in the presence of high background noise levels. Most critically, there was a significant change in attenuation characteristics of the ER-3A Tubephone, which was dependent on the insertion depth of the ear-tip.