Abstract
Introduction: A nonsurgical bone conduction hearing aid (BCHA) is a well-established treatment for children with congenital unilateral microtia and atresia (UMA). To date, limited studies have evaluated the audiological characteristics of the different wearing modes in the same nonsurgical BCHA. Methods: Eighteen patients with UMA aged 5–24 years were included. Warble tones at frequencies of 0.5, 1, 2, and 4 kHz were presented to determine functional hearing gain (FHG) of hearing thresholds (in dB HL) in the sound field. The speech perception abilities were assessed by the speech discrimination score (SDS, in %) of monosyllables, disyllables, and sentences in quiet and noise using the Chinese Mandarin speech test materials. Hearing outcomes were evaluated with the ADHEAR™ worn on a softband and with an adhesive adapter. A correlational analysis was conducted to analyze the correlations between variables (e.g., age, height, weight, body mass index [BMI], bone conduction pure-tone threshold, and air conduction pure-tone threshold) and the differences in the two wearing modes. Results: The mean FHG (standard deviation, SD) at 0.5–4 kHz was 20.63 (3.94) dB HL with the adhesive adapter and 26.39 (3.15) dB HL with the softband. When aided with the BCHA, significant improvements in SDS were revealed in all Mandarin speech test material lists either in quiet or noise for both wearing modes. Compared with the adapter mode, the softband provided higher aided SDS values. Correctional analyses revealed that higher BMI values were positively associated with larger delta outcomes between the two coupling methods of the softband and adhesive adapter in patients with UMA. Furthermore, a larger delta average FHG of 0.5–4 kHz was consistently associated with larger delta monosyllabic SDS in quiet, disyllabic SDS in quiet, and disyllabic SDS in noise. Discussion: To the best of our knowledge, this is the first study to compare the hearing benefits of coupling methods using novel adhesive adapters and conventional softbands with the same audio processor (ADHEAR™). Under uniform internal settings, softband integration provided more hearing benefits than adhesive adapter integration, and the differences were more obvious in patients with higher BMI values. Besides, a brief measurement of FHG can be utilized to predict individualized speech perception levels.
