Effects of tubing length and coupling method on hearing threshold and real-ear to coupler difference measures

Validation of an integrated pressure level measured earmold wideband real-ear-to-coupler difference measurement

OBJECTIVE

To validate measurement of predicted earmold wideband real-ear-to-coupler difference (wRECD) using an integrated pressure level (IPL) calibrated transducer and the incorporation of an acoustically measured tubing length correction.

DESIGN

Unilateral earmold SPL wRECD using varied hearing aid tubing length and the proposed predicted earmold IPL wRECD measurement procedure were completed on all participants and compared.

STUDY SAMPLE

22 normal hearing adults with normal middle ear status were recruited.

RESULTS

There were no clinically significant differences between probe-microphone and predicted earmold IPL wRECD measurements between 500 and 2500 Hz. Above 5000 Hz, the predicted earmold IPL wRECD exceeded earmold SPL wRECDs due to lack of standing wave interference. Test-retest reliability of IPL wRECD measurement exceeded the reliability of earmold SPL wRECD measurement across all assessed frequencies, with the greatest improvements in the high frequencies. The acoustically measured tubing length correction largely accounted for acoustic effects of the participant's earmold.

CONCLUSIONS

IPL-based measurements provide a promising alternative to probe-microphone earmold wRECD procedures. Predicted earmold IPL wRECD is measured without probe-microphone placement, agrees well with earmold SPL wRECDs and is expected to extend the valid bandwidth of wRECD measurement.

Validity and reliability of integrated pressure level real-ear-to-coupler difference measurements

OBJECTIVES

(1) To validate the measurement of foam-tip real-ear-to-coupler differences (wRECD) using an integrated pressure level (IPL) method and (2) to compare the reliability of this method to SPL-based measurement of the wRECD.

DESIGN

SPL-based wRECD and the proposed IPL wRECD measurement were completed bilaterally. Test-retest reliability of IPL wRECD was determined with full re-insertion into the ear canal and compared to published SPL wRECD test-retest data.

STUDY SAMPLE

22 adults with normal hearing and middle ear status were recruited.

RESULTS

Differences between SPL-based wRECD and IPL wRECD measurements were within 1.51 dB on average below 5000 Hz. At and above 5000 Hz, IPL wRECD exceeded SPL wRECDs by 6.11 dB on average. The average test-retest difference for IPL wRECD across all assessed frequencies was 0.75 dB with the greatest improvements in reliability found below 750 Hz and above 3000 Hz.

CONCLUSIONS

IPL wRECD yielded improved estimates compared to SPL wRECD in high frequencies, where standing-wave interference is present. Independence from standing wave interference resulted in increased wRECD values above 4000 Hz using the IPL measurement paradigm. IPL wRECD is more reliable than SPL wRECD, does not require precise probe-microphone placement, and provides a wider valid wRECD bandwidth than SPL-based measurement.

Real-Ear-to-Coupler Difference: Physical and Perceptual Differences

PURPOSE

The real-ear-to-coupler difference (RECD) is a recommended measure for accurate hearing aid fittings, especially for pediatric populations. However, for adults, many clinicians question whether it is necessary.

METHOD

Hearing aids were fit on two groups of 85 older adults seen at a Veterans Administration audiology clinic. One group was fit using RECD measurements, whereas the second group was fit with population-based average RECD values. The two groups had similar pure-tone hearing thresholds.

RESULTS

Like previous studies, there was little difference between the measured RECD for the right and left ears among the participants. Although the majority of the measured RECDs were within 1 SD of the mean, approximately 20% of those measured were outside of the normal range. It also was found that all participants produced lower (improved) Hearing Handicap Inventory for Elderly-Screening (HHIE-S) scores from pre- to postfitting, thus suggesting a reduction in self-perceived hearing handicap.

CONCLUSIONS

Despite having similar prefitting HHIE-S scores, those participants who had their hearing aids fit using measured RECD values had lower postfitting scores than the group that was fit with average RECD values. Furthermore, there was a significant difference between the groups on several questions of the International Outcome Inventory-Hearing Aids, suggesting that there was higher satisfaction with the fittings based on the custom RECD rather than the fittings based on the average RECD. This study demonstrated that, in addition to performing verification using real-ear measurements, accurate conversion of dB HL to dB SPL using personalized RECD likely improved hearing aid satisfaction.

Real ear measurement (REM) and auditory performances with open, tulip and double closed dome in patients using hearing aids

OBJECTIVE

The aim of the study is to evaluate the importance of acoustic modifications generated by different commercially available ear-tips, focused on domes of receiver in the canal hearing aids using Real Ear Measurement (REM).

METHODS

We enrolled 110 people selecting 200 ears bearers of hearing aids. In every patient, we performed REM and audiological tests with three different dome types: Open, Tulip and Double Closed (DC). Data about real-ear occluded gain (REOG), Pure Tone Average (PTA), Word Recognition Score (WRS) with aids switched on in Free Field, Ear and Auditory Comfort were collected and analyzed.

RESULTS

REOG gain was statistically significant different between the three types of dome, with a DC that always closes the external auditory canal (EAC) (p < 0.001). There was no statistically significant difference between the PTA (p = 0.11). Regarding the WRS there were statistically significant differences between Open and DC dome (p < 0.001) and between Tulip and DC dome (p < 0.001), with worse discrimination when using DC. Both auditory and ear comfort are worse in the DC than in the other two domes (p < 0.001). From measured REOG gain values, in 135 cases Tulip dome does not occlude the EAC, with a statistically significant difference compared to DC (p < 0.001; Odd Ratio 0.0012; 95% CI 0.001-0.0196).

CONCLUSION

Our study confirms the necessity to perform REM to evaluate if the prescription target is achieved, especially when tulip domes are used, because they may not occlude the ear canal, causing in some cases the reduction of the vocal discrimination.

Detecting and Learning New Words: The Impact of Advancing Age and Hearing Loss

PURPOSE

Lexical acquisition was examined in children and adults to determine if the skills needed to detect and learn new words are retained in the adult years. In addition to advancing age, the effects of hearing loss were also examined.

METHOD

Measures of word recognition, detection of nonsense words within sentences, and novel word learning were obtained in quiet for 20 children with normal hearing and 21 with hearing loss (8-12 years) as well as for 15 adults with normal hearing and 17 with hearing loss (58-79 years). Listeners with hearing loss were tested with and without high-frequency acoustic energy to identify the type of amplification (narrowband, wideband, or frequency lowering) that yielded optimal performance.

RESULTS

No differences were observed between the adults and children with normal hearing except for the adults' better nonsense word detection. The poorest performance was observed for the listeners with hearing loss in the unaided condition. Performance improved significantly with amplification to levels at or near that of their counterparts with normal hearing. With amplification, the adults performed as well as the children on all tasks except for word recognition.

CONCLUSIONS

Adults retain the skills necessary for lexical acquisition regardless of hearing status. However, uncorrected hearing loss nearly eliminates these skills.