Otolaryngology - Research Publications

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Author: Chambers, Scott × Author: Hampson, Amy × Author: O'Leary, Stephen ×

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    Spironolactone Ameliorates Cochlear Implant Induced Endolymphatic Hydrops.
    Creber, NJ ; Eastwood, HT ; Hampson, AJ ; Lo, J ; Zhang, D ; Chambers, SA ; Bester, CW ; Thorne, PR ; O'Leary, SJ (Ovid Technologies (Wolters Kluwer Health), 2022-07-01)
    BACKGROUND: Endolymphatic hydrops (EH) has been observed in both animal and human cochleae following cochlear implant (CI) surgery. We tested whether EH could be eliminated by administration of mineralocorticoid steroid antagonist spironolactone and explored the electrophysiological consequences of this. METHODS: Sixty-four adult guinea pigs underwent cochlear implantation with a dummy electrode. Animals then survived either 2, 7, or 28 days. Auditory function was monitored by recording electrocochleography from the round window membrane preimplantation, and on the last day of the experiment. Spironolactone or control solution was added to animals' feed for 7 days (if they survived that long) beginning immediately prior to surgery. The presence of EH was determined using thin-sheet laser imaging microscopy. RESULTS: Treatment with spironolactone resulted in significant reduction in EH in the second cochlear turn 7 days postimplantation. In all animals, the compound action potential (CAP) threshold was elevated 2 days postimplantation, but for most frequencies had recovered substantially by 28 days. There was no treatment effect on CAP thresholds. SP/AP ratios were elevated at day 2. The amplitude growth of the CAP did not differ between test and control groups at any time after implantation. CONCLUSIONS: EH can be suppressed by antagonism of mineralocorticoid receptors in the week after cochlear implantation. Reduction in EH did not lead to any change in hearing, and there was no indication of synaptopathy signalled by reduced CAP amplitude at high sound intensities. We found no electrophysiological evidence that EH early after implantation impacts negatively upon preservation of residual hearing.
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    Effect of cochlear implantation on middle ear function: A three-month prospective study
    Wasson, JD ; Campbell, L ; Chambers, S ; Hampson, A ; Briggs, RJS ; O'Leary, SJ (WILEY, 2018-05)
    OBJECTIVES/HYPOTHESIS: To determine if cochlear implantation has a delayed effect on the middle ear conductive hearing mechanism by measuring laser Doppler vibrometry (LDV) of the tympanic membrane (TM) in both implanted and contralateral control ears preoperatively and 3 months postoperatively, and then comparing the relative change in LDV outcome measures between implanted and control ears. STUDY DESIGN: Prospective cohort study. METHODS: Eleven preoperative adult unilateral cochlear implant recipients in previously unoperated ears with normal anatomy and aerated temporal bones were included in this study. The magnitude and phase angle of umbo velocity transfer function in response to air- conduction (AC) stimulus, and the magnitude of umbo velocity in response to bone- conduction (BC) stimulus were measured in the implant ear and the contralateral control ear preoperatively and 3 months postoperatively and compared. RESULTS: No significant changes in the magnitude or phase angle of TM velocity in response to either AC or BC stimulus were observed in the implanted ear relative to the contralateral control ear 3 months following cochlear implantation. CONCLUSIONS: From the results of LDV measurements, it can be said that cochlear implantation has no significant delayed effect on the middle ear conductive mechanism. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:1207-1212, 2018.