In this study the occlusion effect was quantified for five types of earmolds with different venting. Nine normal-hearing listeners and ten experienced hearing aid users were provided with conventional earmolds with 1.6 and 2.4 mm circular venting, shell type earmolds with a novel vent design with equivalent cross-sectional vent areas, and nonoccluding soft silicone eartips of a commercial hearing instrument. For all venting systems, the occlusion effect was measured using a probe microphone system and subjectively rated in test and retest sessions. The results for both normal-hearing subjects and hearing aid users showed that the novel vents caused significantly less occlusion than the traditional vents. Occlusion effect associated with the soft silicone eartip was comparable to the nonoccluded ear. Test-retest reproducibility was higher for the subjective occlusion rating than for the objectively measured occlusion. Perceived occlusion revealed a closer relationship to measured occlusion in the ear in which the measured occlusion effect was higher ("high OE" ear) than in the "low OE" ear. As our results suggest that subjective judgment of occlusion is directly related to the acoustic mass of the air column in the vent, the amount of perceived occlusion may be predicted by the vent dimensions.

ObjectiveThe original Danish translation of the international outcome inventory for hearing aids (IOI-HA) proved problematic as the wording of item 5 was not semantically clear, rendering the questionnaire internally inconsistent. The objective of this study was to examine data collected with a revised Danish translation of the IOI-HA in order to: (1) evaluate the effect of the revision, and (2) to examine if the psychometric properties of the revised translation of the IOI-HA are equivalent to those of previously validated translations.DesignPsychometric properties were evaluated performing inter-item correlation analysis, principal component analysis, and item-total correlation.Study sampleThree hundred forty-one adult hearing-impaired participants—all of whom were voluntary hearing aid testers attached to the Global Audiology Group in GN ReSound A/S on a non-payment basis — were mailed a revised Danish IOI-HA questionnaire.ResultsStatistical analysis revealed good internal consistency along with a clear division of items into two distinct factors.ConclusionsThe revised Danish translation of the IOI-HA proves internally consistent. Furthermore, it possesses psychometric properties equivalent to those reported in several corresponding studies of other translations. Data obtained from it can therefore validly be considered comparable to data obtained from previously validated translations of the IOI-HA.

Differences between conventional PTA and in-situ threshold levels may be attributed to (1) frequency, (2) device/hearing loss, and (3) calibration/manufacturer effects. Frequency effects primarily resulting in an overestimation of hearing loss by in-situ audiometry in the low and mid frequencies are mainly due to sound drain-off through vents and leaks. Device/hearing loss effects may be due to leakage as well as boundary effects because in-situ audiometry is confined to a limited measurement range. Finally, different calibration approaches may result in different offset levels between PTA and in-situ audiometry calibration. In some cases, the observed threshold differences of up to 10-15 dB may translate to varied hearing aid fittings for the same user depending on how hearing threshold levels were measured.

The benefit of bilateral hearing aids is well documented, but many hearing-aid users still wear only one aid. It is plausible that the occlusion effect is part of the reason for some hearing-aid users not wearing both hearing aids. In this study we quantified the subjective occlusion effect by asking ten experienced users of bilateral hearing aids and a reference group of ten normal-hearing individuals to rate the naturalness of their own voice while reading a text sample aloud. The subjective occlusion effect was evaluated in the unilateral versus bilateral condition for a variety of vent designs in earmolds and in a custom hearing aid. The subjective occlusion effect was significantly higher for bilateral hearing aids with all vent designs with the exception of a non-occluding eartip option. The subjective occlusion effect was reduced with the more open vent designs in both the unilateral and bilateral conditions. Assuming that the occlusion effect is a barrier to bilateral hearing aid use, these results indicate that open-hearing-aid fittings can help promote the use of two aids.

ObjectiveThe last decade has offered a multitude of instant fit coupling systems to be fitted with behind-the-ear (BTE) hearing aids. The impact of these designs on the reliability of real ear measurements (REMs) has not been reported. The purpose of this study was to obtain REM reliability data for instant fit coupling systems.DesignREM reliability data was obtained for four different instant-fit coupling systems and for standard size 13 tubing and custom earmolds. REMs were performed for all five coupling systems two times and by two examiners.Study sampleTen normal-hearing individuals (20 ears) served as participants.ResultsThe REM test-retest reliability is high for the four instant fit coupling systems as well as for the custom earmolds. The REM inter-examiner reliability is high for three of the four instant fit coupling systems.ConclusionsCarrying out REMs with instant fit coupling systems appears to be fundamentally no different than performing REMs with conventional hearing aids. For either, care should be taken in probe tube placement in terms of insertion depth and maintaining the probe tube placement, and other best practices regarding test environment and test setup should be observed.