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direct contact between the FMT and RWM could be attained, the ‘‘direct coupling with no fascia interposed’’ technique as per Rajan et al. (8) was utilized. Vibroplasty Coupling Measurements The measurement of the vibroplasty thresholds is similar to pure-tone audiometry with the stimulus being presented via the FMT. All vibroplasty measurements were implemented using a spare clinic Amade´ low processor and the ‘‘vibrogram’’ function available in the manufacturer’s software. The vibrogram is a pure- tone audiogrammeasured through the VSB processor and implant. Behavioral vibroplasty thresholds are determined by applying the modified Hughson-Westlake method (15). It is now common pro- cedure and recommended by the manufacturers to use the thresholds attained via the vibrogram, to set the processor’s initial fitting levels. Results are reported on a decibel scale, which is normalized to the maximum transducer excitation voltage of the FMT (dB re. 4.47 K V). To find a relationship between vibroplasty thresholds and traditional bone conduction thresholds, the vibroplasty thresholds are entered into a scatter plot versus corresponding bone conduction thresholds. In addition, a linear trend is calculated for each test fre- quency. The orthogonal distance between the trend line and data points of one individual subject, measured in decibels and averaged across all test frequencies, is used to calculate the relative coupling efficiency. The underlying assumption is that data points below the regression line are indicative for ‘‘good’’ coupling, which means ‘‘better than the average within the study’’. Please see Supplementary Digital Content 1 (http://links.lww.com/MAO/A316) for an example of how coupling efficiency is calculated. Audiologic Testing V Speech in Quiet Standard audiologic measures included air and bone con- duction testing, and monosyllabic speech perception testing using AB (Arthur Bootroyd) Words (16). These were conducted preoperatively and at 1, 3, 6, and 12 months postoperatively and annually thereafter. The free field speech testing in quiet consisted of recorded Consonant Nucleus Consonant (17) (CNC) monosyllabic words presented at 65 dB SPL through a speaker located 1 m directly in front of the patient in the following conditions: 1. implanted ear unaided, and 2. implanted ear wearing the VSB. The contralateral ear was effectively masked.

Quality of Life Measure The Tinnitus Reaction Questionnaire (TRQ; 19) was used to assess the impact of tinnitus on well-being, emotions, and lifestyle. The TRQ was completed before and 3, 6, and 12 months post- surgery after to compare the postoperative outcomes. A maximum score of 104 and a minimum score of 0 can be attained on the TRQ. A score of 17 and above denotes clinically significant tinnitus disturbance. Surgical Technique A diagrammatic representation of the FMT positions employed can be seen in Figure 1. When coupling the FMT to the stapes or incus, it was critical to confirm transmission through the chain or remnant via the presence of the round window reflex. This in- volved palpation of the stapes which induces a movement of the RWM. The FMT is then crimped onto the long process of the incus or the posterior crus of the stapes superstructure. When the FMT is placed against the round window, the FMT titanium attachment clip is removed. The FMT conductor link cable is then preshaped to allow placement of the FMT against the RWM. This is after reduction of the superior and anterior lip of the round window niche to facilitate the FMT contact with the RWM. In cases of a funnel-shaped or a deep, narrow round window niche, only a limited degree of lip reduction is possible as the risk of an injury to the cochlear endosteum or RWM is high. Statistical Analysis A Mann-Whitney U test was used to compare coupling effi- ciency of the FMT in various placements: (a) fascia between FMT and RW, (b) direct FMT contact, (c) FMT crimped to incus (long process), and (d) FMT crimped to stapes (on the posterior crus). The Wilcoxon signed-rank test was used to determine if there was a significant change in results of speech recognition in quiet. To detect differences between the preoperative TRQ test results, a difference of 40% was deemed to be significant as per the recommended analysis (18). A nonparametric Wilcoxon signed-rank test was also applied.

RESULTS

Surgical Outcomes Of the 16 patients, three required FMT re-positioning within the first 6 months after implantation as per the results

FIG. 2. Summary of coupling efficiency for individual patients. The smaller value is consistent with better coupling efficiency.

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