Three studies are reported assessing the validity of AMTAS, an automated method for obtaining an audiogram, including air- and bone-conduction thresholds (stimuli delivered by a forehead-placed transducer) with masking noise presented to the non-test ear. In Study 1, six subjects at each of three sites were tested using manual audiometry by two audiologists at each site. The mean differences between the audiograms for the paired audiologists provided a measure of the reliability of traditional audiometry. In Study 2, thirty subjects (5 normal hearing, 25 hearing impaired) were tested using AMTAS and manual audiometry. For air-conduction thresholds, AMTAS-manual differences were similar to inter-tester differences in Study 1, but for bone-conduction thresholds, the former were larger. Two possible sources of the greater differences were identified, (1) incorrect reference-equivalent threshold force levels for forehead bone conduction, and (2) a differential effect of middle-ear disease on forehead and mastoid bone-conduction thresholds. In Study 3, intersubject variability was studied for forehead and mastoid bone-conduction thresholds. The results indicate similar variability for the two placement sites.

This version of the TEN test can be used with ER-3A insert earphones.

Due to individual characteristics such as head size, earmould type, and earmould venting, the directional benefit that an individual will obtain from a hearing aid cannot be predicted from average data. It is therefore desirable to measure real ear directional benefit. This paper demonstrates a method to measure real ear hearing aid directivity based on a general approach to measure the broadband output signal-to-noise ratio of a hearing aid. Errors arising from non-linearity were tested in simulation and found to be low for typical hearing aid compression ratios. Next, the efficacy of the method to estimate directional benefit was demonstrated on KEMAR. Finally the variability of directional benefit was explored in real-ears. Significant differences in signal-to-noise ratio between directional and omnidirectional microphone settings were demonstrated at most azimuths. Articulation-Index-weighted directional benefit varied by more than 7 dB across ears at some azimuths. Such individual variation in directional benefit has implications when fitting hearing aids: it should not be assumed that all users will receive similar directional benefit from the same hearing aid.