Brainstem evoked responses obtained from hearing-aided adults

Abstract

Traditionally, the evaluation of auditory functioning in the hearing-aided patient has been limited to subjective response measures. This report demonstrates that brainstem evoked responses can provide an objective and reliable measure of auditory performance in such individuals. Moderate-output body-level aids were worn by three normal-hearing adults, on whom unaided responses had previously been obtained. Highly reliable responses to clicks, tone, and noise bursts were obtained from all subjects. Increases in the gain of the aid, and thus signal loudness, produced shorter latency and larger amplitude responses, as expected on the basis of unaided input-output functions. The number of decibels above physiological threshold required to generate a 6.0-msec latency response was smaller in the aided when compared to the unaided condition, thus mimicking the electrophysiological finding in “recruiting” patients. Variations in the low-frequency portion of the aid's frequency-response curve produced little change in the evoked response, while increases in its high-frequency cutoff produced shorter latencies. The reliable and systematic relation between subjective sensation, hearing-aid characteristics, and neuro-electrical response appears to warrant the continued investigation of the use of brainstem evoked responses for hearing aid fitting in hearing-impaired populations.

The auditory acclimatization effect in sensorineural hearing-impaired listeners: Evidence for functional plasticity

“…Electrophysiological changes were also reported in an older study (Hecox et al, 1975). These authors recorded ABRs in three normal-hearing adults Wtted with moderate HA gain.…”

The output of compression hearing aids with a transient input signal

“…A number of authors have attempted to assess the fit of the hearing aid and adjust the electroacoustic settings of the hearing aid on the basis of ABR responses to an aided ear. That is, the acoustic signal used to elicit the ABR is delivered to the hearing aid, which amplifies the signal and delivers it to the clients ear (Cox & Metz, 1980;Gorga, Beauchaine and Reiland, 1987 ;Hecox, 1983;Mahoney, 1985;McPherson and Clark, 1983;Sander, 1983;Kileny, 1982;Hecox, Breuninger and Krebs, 1975;and Beauchaine, Gorga, Reiland, and Larson 1986). The above authors all differ somewhat in the approach they use for obtaining aided ABR's, but the goal is the same, and that is to normalize, via amplification, the amplitude, slope, threshold or latency of components of the ABR waveform.…”