Do Changes in Transtympanic Electrocochleography (TT-ECochG) Reflect the Dynamics of Endolymphatic Hydrops on MRI? Audiological and Radiological Longitudinal Analysis in Patients with Severe Ménière's Disease After Vestibular Neurectomy-A Pilot Study.

Objectives

The aim of this study was to evaluate long-term changes in transtympanic electrocochleography (TT-ECochG) following vestibular neurectomy in patients with Ménière's disease (MD) and to investigate their relationship with endolymphatic hydrops (EH) degree and hearing outcomes.

Methods

This pilot study included five patients with unilateral MD eligible from a cohort of twenty patients who underwent middle fossa vestibular neurectomy. All participants completed preoperative and 2-year postoperative clinical and audiological tests, including TT-ECochG; EH degree was analyzed in delayed gadolinium-enhanced magnetic resonance images (MRI). Changes in TT-ECochG parameters were analyzed in relation to MRI findings.

Results

All patients achieved complete control of vertigo and improvement in the AAO-HNS functional level. Hearing deterioration of ≥10 dB was observed in two patients (40%). Cochlear EH remained unchanged in all patients, whereas vestibular EH reduction was visualized in two patients (40%) after surgery. Decreased SP/AP amplitude and/or area ratios were observed in two patients (40%), whereas increased values were found in two others (40%). No postoperative TT-ECochG response was obtained in one patient because of profound postoperative hearing loss. Overall, changes in TT-ECochG parameters did not parallel MRI findings.

Conclusions

This pilot study demonstrates that postoperative TT-ECochG changes after vestibular neurectomy are heterogeneous and do not consistently parallel MRI changes in endolymphatic hydrops.