1. Introduction
For about four decades, a bone conduction (BC) hearing device may lead
to hearing improvement in patients with single-sided deafness (SSD) and
conductive or mixed hearing loss (CHL or MHL)(1). By vibration of the
skull or structures of the middle ear, these devices transmit a signal
directly into the cochlea.
BC hearing devices (BCHDs) can be divided into implantable and
non-implantable devices. While implantable devices consist of an implant
and an audio processor, with surgery necessary, non-implantable devices
consist of an adapter and an audio processor, with surgery nor
necessary(2, 3). For implantable BCHDs well known the percutaneous and
transcutaneous bone-anchored hearing aids (BAHAs) like Ponto™ System and
the BAHA® Attract or Connect Systems(4), the transcutaneous
osseointegrated steady-state system (Osia™)(5) or the transcutaneous BC
implant Bonebridge®(6), as well as the transcutaneous middle ear implant
system Vibrant Soundbridge®(7). As non-implantable BCHDs, in 2001 a
softband adapter for a BCHD audio processor was introduced, especially
for children. Many studies showed that the softband BAHA is a
successfully treatment for CHL(8-10). However, due to the static
pressure on the head, some children and adults don’t tolerate a softband
as a long-term solution(11). As a new non-implantable BCHD was
introduced, the ADHEAR(12, 13). System, especially for small
children(14-16). This system works without putting any pressure on the
skin. The key concept of the ADHEAR system is a disposable adapter
sticking to the hairless skin behind the ear, with an audio processor
clicking onto this adapter. Previous studies showed that the audiometric
results using the ADHEAR system are similar to those using a softband
BAHA system(16), while the wearing time and acceptance in children and
adults is preferred over a softband BAHA system(12, 16).