Audiological Performance of ADHEAR Systems in Simulated Conductive Hearing Loss: A Case Series with a Review of the Existing Literature

Abstract

A new non-invasive adhesive bone conduction hearing device (ABCD) has been proposed as an alternative solution for reversible bilateral conductive hearing loss in recurrent or long-lasting forms of otitis media with effusion (OME) in children that cannot undergo surgical treatment. Our aim was to assess the effectiveness of ABCD in children with OME. Twelve normal-hearing Italian-speaking volunteers, in whom a conductive hearing loss was simulated, participated in the study. The free-field average hearing threshold was determined and, to evaluate binaural hearing skills, loudness summation and the squelch effect were assessed. Five conditions were tested: (1) unaided without earplugs, (2) unaided with bilateral earplugs, (3) aided right ear with bilateral earplugs, (4) aided left ear with bilateral earplugs, and (5) bilateral aid with bilateral earplugs. Post-hoc analysis showed a significant statistical difference between plugged, unplugged, and each aided condition. The main results were a better loudness summation and a substantial improvement of the squelch effect in the bilaterally aided. Our results suggest that ABCD is a valid treatment for patients with conductive hearing loss that cannot undergo bone conduction implant surgery. It is also important to consider bilateral aids in order to deal with situations in which binaural hearing is fundamental.

Keywords: binaural hearing; bone conduction hearing device; conductive hearing loss; otitis media with effusion.

Figure 1

Right ear. ABCD device in place in a typical subject, where the ear canal is occluded by a custom silicone plug. On the right, a commercial figure of the ABCD showing the external laterale surface is visible, and the microphone ports are visible on the right (in the lower part of the device when worn on the right side).

Figure 2

Speech-in-noise test setup. S, signal (speech) source location, N, noise source location. (A) Loudness summation test; (B) Right squelch effect test; (C) Left squelch effect test.

Figure 3

Average free-field threshold in each test condition.

Figure 4

Loudness summation SRT₅₀ for the unaided and bilaterally aided plugged condition.

Figure 5

Aided squelch SRT50. (A) Overall scores with noise lateralized to the unaided ear, or “best scenario”; (B) Overall scores with noise lateralized to the aided ear, or “worst scenario”; (C) Overall bilaterally aided condition.