e. Use of a hearing aid. A candidate who uses a hearing aid(s) should be administered the HINT or other tests that meet the performance characteristics as outlined in paragraph "d" to assess speech comprehension ability in noise and quiet. Both tests must be administered by sound field methods rather than headphones. An aided audiogram can be reviewed to evaluate sound detection ability. Before functional testing, the examining physician must ensure that the aid(s) has been worn regularly for at least one month, since it takes some practice before an individual obtains the maximum benefit from the hearing aid(s). Furthermore, the examining physician should obtain all records from the audiologist who dispensed the hearing aid(s). The records must include documentation of the fitting program and other hearing aid settings, which are used on a regular basis by the candidate. This information shall be reviewed by the certified audiologist performing the testing procedure to verify that the settings have not been intentionally altered.
The following protocol must be used. No modifications to the candidate's hearing aid program or settings should be made prior to or during the performance of this protocol.
(1) Evaluate whether the hearing aid(s) is working properly. The electroacoustic response characteristics of each hearing aid worn by the candidate should be measured in an appropriate acoustic coupler and test chamber according to ANSI specifications (ANSI 1992 and 1996). The response of the hearing aid(s) should be measured at the four designated input levels with a broadband test signal, as specified in the specifications. All measurements should be printed and retained in the candidate's records. If the hearing aid(s) is not in proper working condition, no further testing should be performed at that time. The candidate may elect to have the hearing aid(s) repaired or replaced and may return to repeat the protocol. In this event, the entire protocol, including measurements of the electroacoustic response characteristics of the hearing aid(s), should be repeated with the new or repaired hearing aid(s). Hearing aid sales, repairs, and replacements should be from an independent provider other than the provider of the functional assessment services.(2) Review the candidate's regular fitting program and settings. The fitting program and settings should be equivalent to those measured according to subparagraph (1). If they are not equivalent, no further testing should be performed at that time.(3) Determine whether the functional gain is both physiologic and appropriate for the candidate's hearing loss. Unaided and aided binaural sound field thresholds should be measured at 250Hz, 500Hz, 1000Hz, 2000Hz, 3000Hz, 4000Hz, and 6000Hz, using warble tone stimuli presented from a loudspeaker positioned 1 meter in front of the candidate at 0 degrees azimuth. If the functional gain is not physiologic and appropriate, then no further testing should be performed at that time.(4) Perform aided sound field HINT or other approved testing in noise and quiet. Compare the results to the site-specific normal values for sound field noise front, noise right, and noise left conditions. If the measured thresholds are better than the fifth percentile under all three conditions, then the noise testing shall be repeated with the background noise fixed at 80dB(A). The same normative values used with the standard background noise levels may be used to assign percentile scores to these results. The examining physician may use the evaluation algorithm described in Hearing Guidelines-Abnormal Audiogram, with one exception. Many present-day hearing aids employ methods of sound processing that vary as a function of the background noise level, and it is necessary to measure aided sound field HINT thresholds through a range of background noise levels. Therefore, candidates who use hearing aid(s) should be functionally normal both under standard HINT background noise levels (i.e., 65dB) and at levels that are commonly encountered in the field (80dB).
The candidate has met the required hiring standards if the candidate has demonstrated acceptable functional ability when wearing a hearing aid(s) and wears a hearing aid(s) when assigned to field duty.