A new coupler with controlled preload to improve round window coupling of acoustic implants

Introduction:

In patients with mixed hearing loss, the Vibrant Soundbridge (VSB) round window application is often problematic. First, the mismatch in diameter between the Floating Mass Transducer (FMT) and the round window (RW) makes it difficult to position and steady the FMT on the round window membrane (RWM). Secondly, placing cartilage behind the FMT builds up a preload but the forces are uncontrolled and coupling efficiency varies greatly. Thus, a new coupler was developed for the VSB FMT to achieve a standardized coupling at the RWM.

Method:

The Hannover Coupler consists of a clip that holds the FMT with a spherical coupler on the front end (facing the RWM) and with a spring on the back end of the clip. The Hannover Coupler was implanted in a 66-year old patient with mixed hearing loss (bone conduction [BC] PTA₄= 42.5 dB HL; air conduction PTA₄ > 102.5 dB HL) undergoing a VSB revision surgery. Six months after the revision, the audiological outcome of the patient (BC threshold, aided threshold, effective gain, word recognition scores [WRS, %] in quiet with the Freiburg monosyllable test at 65 dB SPL and the Oldenburg Sentence Test [OLSA, dB SNR] in noise) was determined and compared to the outcome of other coupling types.

Result: The first Hannover Coupler patient obtained good speech perception in quiet (80% WRS) and in noise (-3.3 dB SNR). The effective gain with the Hannover Coupler improved by Ø 21.2 dB across frequencies (1 to 6 kHz) but was similar at 0.5 kHz compared to the standard coupling with RW-Titanium Coupler (Busch et al. 2016).

Discussion:

The Hannover coupler provides a viable option for the round window application of the VSB FMT.

Publication History

Publication Date:
18 April 2018 (online)