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|Title: ||A technical comparison of digital frequency-lowering techniques available in two current hearing aids|
|Authors: ||McDermott, Hugh|
|Keywords: ||Hearing Aid|
|Issue Date: ||Jul-2011|
|Publisher: ||PLoS ONE|
|Citation: ||McDermott, H. (2011). A technical comparison of digital frequency-lowering techniques available in two current hearing aids. PLoS ONE, 6(7), e22358.|
|Abstract: ||Background: Recently two major manufacturers of hearing aids introduced two distinct frequency-lowering techniques that
were designed to compensate in part for the perceptual effects of high-frequency hearing impairments. The Widex
‘‘Audibility Extender’’ is a linear frequency transposition scheme, whereas the Phonak ‘‘SoundRecover’’ scheme employs
nonlinear frequency compression. Although these schemes process sound signals in very different ways, studies
investigating their use by both adults and children with hearing impairment have reported significant perceptual benefits.
However, the modifications that these innovative schemes apply to sound signals have not previously been described or
compared in detail.
Methods: The main aim of the present study was to analyze these schemes’technical performance by measuring outputs
from each type of hearing aid with the frequency-lowering functions enabled and disabled. The input signals included
sinusoids, flute sounds, and speech material. Spectral analyses were carried out on the output signals produced by the
hearing aids in each condition.
Conclusions: The results of the analyses confirmed that each scheme was effective at lowering certain high-frequency
acoustic signals, although both techniques also distorted some signals. Most importantly, the application of either
frequency-lowering scheme would be expected to improve the audibility of many sounds having salient high-frequency
components. Nevertheless, considerably different perceptual effects would be expected from these schemes, even when
each hearing aid is fitted in accordance with the same audiometric configuration of hearing impairment. In general, these
findings reinforce the need for appropriate selection and fitting of sound-processing schemes in modern hearing aids to suit
the characteristics and preferences of individual listeners.|
|Appears in Collections:||Bionic Hearing Research Publications|
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