Bone anchored hearing aids 'BAHAs' in children

BACKGROUND: The technique for applying bone-anchored hearing aids (BAHAs) by the use of osseointegration is today widely established for both adults and children. The BAHA concept is suitable for patients with recurrent ear infections or car malformations who cannot use conventional hearing aids, which are placed altogether or partially in the ear canal. Long-term results are well documented in adults but are lacking in children. Most patients are fitted with unilateral BAHA even though they have bilateral hearing loss. However, recent studies in adults with bilateral hearing loss have shown better hearing results with bilateral BAHA fitting compared to unilateral. Moreover, a recently published metaanalysis on the consequences of unilateral hearing loss in children has implied that educational and behavioural problems as well as delayed speech and language development can occur. Improved hearing outcomes have lately been presented in adults with single-sided deafness and unilateral conductive hearing loss fitted with unilateral BAHA why unilateral BAHA ought to be explored also in children.

AIMS: The study was performed with the aim to increase our knowledge of long-term results and new areas of use of BAHA in children with either uni- or bilateral conductive hearing loss. A further objective was to evaluate the influence of single-sided congenital conductive hearing loss on hearing function and to investigate perceived problems in patients with congenital ear malformation where no hearing intervention has been performed.

MATERIAL AND METHODS: Altogether 127 patients and 15 controls, mainly children were enrolled in the present study. The included subjects had either uni-or bilateral conductive hearing loss. The patients with bilateral hearing loss were fitted with BAHAs uni-or bilaterally whereas the patients with unilateral hearing loss were predominantly untreated or fitted with unilateral BAHA. Medical records were examined. Psychoacoustic tests including tone and speech audiometry, sound localizations tasks, as well as satisfactory measurements were employed.

RESULTS AND CONCLUSION: Long-term results in children concerning implant failure rate, adverse skin reactions and function pattern of the BAHA were in parity with previous measured outcomes in adults. Furthermore, bilateral BAHAs in patients, both children and adults gave additional hearing effects such as improved speech reception/recognition and sound localization ability as well as binaural hearing to some extent. Unilateral hearing aid fitting in children gave some supplementary benefit in terms of improved speech recognition in noise but no positive influence on sound localization ability was recorded. Nevertheless, all children fitted with hearing aids, either uni-or bilaterally reported positive outcome with their devices. Two problem areas were identified in the hearing impaired children: in reaction to sounds and with speech intelligibility.

Finally, in patients with single-sided congenital external ear malformations and associated hearing loss, a deprived auditory function was noticed. This patient cohort also reported a high degree of hearing related problems. In conclusion, BAHA is a good amplification alternative in children with conductive hearing loss. Bilateral BAHAs resulted in supplementary hearing gain compared to one BAHA in both adults and children why bilateral BAHAs could be considered in patients with bilateral conductive hearing loss. Unilateral hearing aid, mainly BAHA might also be beneficial to some extent in children with conductive unilateral hearing loss and a trial with BAHA on Softband could be considered. Complementary intervention should also focus on the alleviation of the high degree of self and guardian reported problems in audition and communication.

List of scientific papers

I. Priwin C, Granstrom G (2005). The bone-anchored hearing aid in children: a surgical and questionnaire follow-up study. Otolaryngol Head Neck Surg. 132(4): 559-65.
https://doi.org/10.1016/j.otohns.2004.09.048

II. Priwin C, Stenfelt S, Granstrom G, Tjellstrom A, Hakansson B (2004). Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation. Laryngoscope. 114(1): 77-84.
https://doi.org/10.1097/00005537-200401000-00013

III. Priwin C, Jonsson R, Hultcrantz M, Granstrom G (2006). Baha in children and adolescents with uni- or bilateral conductive hearing loss. A pilot study of outcomes. [Submitted]

IV. Priwin C, Jonsson R, Magnusson L, Hultcrantz M, Granstrom G (2006). Audiological evaluation and self-assessed hearing problems in subjects with single-sided congenital external ear malformations and conductive hearing loss. [Submitted]