Ref. 1: Materials and methods Details

Transcription

1 Manuscript (Supplemental Material) Ref. 1: Materials and methods Details 1. Subjects Several patients were selected based on their hearing thresholds as well as their limited satisfaction with hearing aids. Six hearing-impaired patients completed the whole study. All patients gave their written consent to participate to the tests. Hearing presented a steep high frequency hearing loss within VSB inclusion criteria (Fish, 21; Sterkers, 23). Moreover, differences in absolute thresholds between both ears were less than 3 db HL. The implanted ear was chosen based on audiological and clinical criteria. All patients had normal middle ear function as revealed by impedance tympanometry and stapedial reflex measurements. 2. Test procedures a. Audiometry Hearing thresholds were determined using pure tone audiometry at six frequencies (.25,.5, 1, 2, 4 and 8 khz). b. Gain Aided and unaided hearing thresholds were measured in free field using warble tones at five frequencies (.25,.5, 1, 2 and 4 khz). c. Speech intelligibility in quiet Correct word recognition score was determined using Lafon monosyllabic words (Lafon, 1964). Each list contained 17 words consisting of three phonemes; one error is counted each time a phoneme is mispronounced or not repeated. The final score is converted to a percentage. Performances were measured at three intensity levels: 4, 5 and 6 db SPL. d. Speech intelligibility in noise The test used to measure intelligibility in noise was specifically conceived by Dodele (Dodele, 1999). It is nowadays routinely used by most audiologists. It consists in five lists of 17 meaningless words (vowel consonant vowel), the 17 consonants being the most frequently used in French language and the 34 vowels selected respect the occurrence of vowels in French language. The noise, close to a cocktail party noise, was specifically conceived to represent everyday situations in which hearing impaired subjects are confronted to. All the sound material (lists of meaningless words and noise) was available on an audio CD. Two loudspeakers, located on each side of the

2 Vibrant Soundbridge versus conventional hearing aid in sensorineural high frequency hearing loss. A prospective study. Eric TRUY (1,2), Bénédicte PHILIBERT (3), Jean-François VESSON (1), Samia LABASSI (3), Lionel COLLET (1,2) ; 1. Département d ORL, Hôpital Edouard Herriot, Lyon, France 2. UMR CNRS 52, Université Claude Bernard, Lyon, France 3. Med-EL France, Vallauris, France Address correspondance and reprint requests to Eric TRUY, M.D., département d Oto-rhino-laryngologie, de Chirurgie Cervico-maxillo-faciale et d Audiophonologie. Hôpital Edouard Herriot, Place d Arsonval, cedex 3, Lyon, France. Tel : (33) Fax : (33) eric.truy@chu-lyon.fr Notes : Supplemental digital content for this article is available on the journal s Web site at

3 patient, delivered the noise. A third loudspeaker in front of the patient delivered the Dodele lists. Patients were familiarized with the test with two training lists. Speech was delivered at a comfortable intensity level to the patient (around 55 db depending on the hearing loss). Then, each list was presented at a different signal-to-noise ratio (S/N), from -6 to +6 db by 3 db step. Lastly, the score was measured by counting one error each time a phoneme was mispronounced or not repeated. 3. Statistical analysis Hearing performances (speech intelligibility in quiet and in noise) were compared in three conditions: unaided, with the hearing aid and with the VSB. Statistical tests were performed with the SPSS software using a within-subject repeated measure analysis of variance (RM ANOVA) with two factors ( device and frequency or device and intensity ). Post-hoc tests were run with a Bonferroni correction due to the multiple conditions.

4 Manuscript (Supplemental Material) Ref. 2: Results details 1. Audiometry Hearing thresholds were measured at six frequencies in both ears, before and after surgery. The comparison of preoperative versus postoperative thresholds is illustrated in figure 1plus for the implanted ear of each patient. Thresholds were found to be very similar with no change after surgery. 2. Gains Figure 2plus shows the individual averaged gains (aided thresholds minus unaided thresholds) at each frequency. Aided thresholds with the VSB appeared systematically better than aided thresholds with the hearing aid 3. Speech intelligibility in quiet Figure 3plus presents individual scores obtained for the six patients. As expected, scores were the best at 6 db SPL, lower at 5 db SPL and the lowest at 4 db SPL. It can also be observed that unaided performances remained good even at the lowest intensity level. 4. Speech intelligibility in noise Individual results are illustrated in figure 4plus, each curve representing one condition. First, it can be observed that in most cases, scores improved with larger S/N. It can be also observed that VSB performances are systematically better than those unaided and with the hearing aid. Figure legends: Figure 1plus: Individual hearing thresholds measured at six frequencies preoperatively (plain line) and postoperatively (dashed line). Figure 2plus: Individual unaided (plain line) and aided thresholds (with the HA: short dashed line; with the VSB: long dashed line) measured at five frequencies.

5 Figure 3plus: Individual speech performances measured in quiet at three intensity levels, unaided (plain line), with the HA (short dashed line) and with the VSB (long dashed line). Figure 4plus: Individual speech performances measured at six signal-to-noise ratios. Plain line shows unaided scores. Short dashed line shows scores with the HA. Long dashed line shows scores with the VSB.

6 Figure 1 (Supplemental) Frequency (khz) -2 Pre-op Post-op AG BLF Threshold (db HL) MJM PS -2 SG TM

7 Figure 2 (Supplemental) Frequency (khz) -2-4 Unaided Hearing aid Vibrant Soundbridge AG BLF Threshold (db SPL) MJM PS SG TM

8 Figure 3 (Supplemental) Unaided Hearing aid Vibrant Soundbridge 4 2 AG BLF Correct word recognition score (%) MJM PS SG TM Intensity (db SPL)

9 Figure 4 (Supplemental) Signal-to-Noise ratio Unaided Hearing aid Vibrant Soundbridge 4 2 AG BLF Correct word recognition score (%) MJM PS SG TM