The Value of Routine Real Ear Measurement of the Gain of Digital Hearing Aids

Abstract

The main aims of this study were: (1) to determine whether routine real ear insertion gain (REIG) measurement is necessary in fitting digital hearing aids; and (2) to assess the extent to which modifying the frequency-gain response of an aid can lead to better matches to the target in cases where the target gain was not initially achieved. The target formula was selected as NAL-NL1 in the programming software of four types of digital hearing aids. REIG measurements on 42 ears showed that 64% of cases failed to come within +/-10 dB of the target at one or more of the following frequencies: 0.25, 0.5, 0.75, 1, 1.5, 2, and 4 kHz. After adjusting the frequency-gain response of the aids, based on the REIG results, 83% of cases came within +/-10 dB of the target. The target was met more often, both before and after adjustment, for aids with seven gain "handles" than for aids with four gain "handles". The results indicate that REIG measurements can and should be used to achieve more accurate fittings but that accurate adjustments are difficult with some aids.

Development of a new method for deriving initial fittings for hearing aids with multi-channel compression: CAMEQ2-HF

“…It is often the case that gains measured at the eardrum differ from the gains specified in the manufacturer's fitting software (Aazh & Moore, 2007). Therefore, it is recommended practice to verify and adjust gains based on real-ear measurements using a probe microphone (Mueller et al, 1992).…”

Comparison: real and simulated ear insertion gain

“…Results have shown that 64% of fits did not reach the prescribed insertion gain by the NAL-NL1 rule at one or more frequencies from 250 to 4000 Hz when the first fit or quick set option was chosen in the programming software 14 . Correlations between age and simulated and true gain were weak and not significant ( Table 2).…”

“…However, even if software demonstrates an equivalence between HAs and prescriptions, these simulations do not truly reflect the performance of these devices in the user's ear. Studies have shown that software simulations tend to overestimate the amplification that is actually provided to the real ear [12][13][14] . The purpose of this study was to compare HA software programming simulated insertion gain with true insertion gain measurements.…”

Addressing age related hearing loss through engineering accessible and affordable hearing technology

“…The response of the LoCHAID with full open volume against the targets of all 11 profiles are shown in Fig 3. To determine goodness of fit, we adopted a Strict and Loose Criteria that has been used previously by other researchers [11,17,19,29,30]. If the response of the device is within 5 dB SPL of the target, then it fits under Strict Criteria, while a response within 10 db SPL is used for the Loose Criteria.…”