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Speech understanding and sound localization with a noninvasive bone conduction system in uni- and bilateral condition
18 April 2018 (online)
The objective of this study was to evaluate the audiological benefit of a new noninvasive bone conduction system (ADHEAR, Med-El, Austria) in normal hearing adults with simulated bilateral conductive hearing loss.
Fifteen subjects were included in the study. All subjects had normal hearing (i.e., bone and air conduction thresholds ≤15 dB HL). Both ears of the subjects were occluded, leading to an averaged sound field PTA of 49 dB HL. Speech understanding in noise was measured with a German matrix test (OLSA). Noise was presented from 0, 90, 180, and 270 °, and speech was presented from the front, the side of the first ADHEAR, and the side contralateral to the first ADHEAR device. Sound localization was assessed using 12 loud speakers arranged in the horizontal plane.
The average functional improvement of the system was 25 dB in the unilateral and 27 dB in bilateral condition. When speech was presented from the front, speech reception thresholds (SRTs) were improved by 3.6 dB in the unilateral and by 4.5 dB in the bilateral condition. With speech presented from the ipsilateral side, SRTs were improved by 4.0 dB in the unilateral and by 3.8 dB in the bilateral condition. When speech was presented from the contralateral side, SRTs deteriorated by 0.6 dB in the unilateral condition. Bilateral use improved the SRT by 3.7 dB in this situation. This effect was compensated by the second ADHEAR (bilateral). The mean absolute error was improved from 81 ° in the unilateral situation to 47 ° in the bilateral situation.
The new non-invasive bone conduction system provides audiological benefits for patients with conductive hearing loss that are comparable to conventional noninvasive bone conduction solutions.