A comparison study of audiological outcome and compliance of bone conduction implantable hearing implants

The present study aimed to evaluate and compare the outcome of different bone conduction hearing implants (BCHIs) in subjects with mixed hearing loss (MHL) and single-sided deafness (SSD) in terms of audiometric results and compliance.

Twenty-one subjects with MHL and 18 subjects with SSD undergoing implantation of Baha connect, Baha attract, or Bonebridge were enrolled. Functional gain, effective gain, and usage rate of BCHIs were retrospectively reviewed.

As for MHL, the functional gain of three devices was not significantly different (p = 0.477), while the effective gain of Bonebridge was higher (- 8.8 [- 15.0, - 3.5] dB) than that of Baha connect (- 20.0 [- 26.3, - 11.3] dB, p = 0.037), especially at 0.5 kHz (p = 0.010) and 1 kHz (p = 0.014). In SSD subjects, the effective gain of Bonebridge was significantly higher than that of Baha attract (- 11.3 [- 15.0, - 7.5] vs - 21.3 [- 21.3, - 16.3] dB, p = 0.012), while the functional gain of Bonebridge and Baha attract was not different. The constant usage rate of BCHIs tends to be higher in MHL subjects [17/21 (82%)] than that in SSD subjects [10/18 (56%)]. In SSD subjects, the constant user group showed higher functional gain than the non-constant user group, with a significant difference at 3 kHz (35.0 [33.8, 45.0] vs 17.5 [10.0, 27.5] dB, p = 0.006).

Bonebridge shows a higher effective gain than Baha connect in the MHL group and Baha attract in the SSD group. The usage rate of BCHIs is lower in SSD than that in MHL. In SSD subjects, the constant user group tended to show higher functional gain than the non-constant user group. Irrespective of the device type, the tendency of higher functional gain of BCHIs, especially at mid frequencies, may potentially lead to yield good compliance in SSD, mandating a meticulous fitting strategy ensuring a sufficient mid-frequency functional gain in SSD.