Cochlear-implantation in a 58 year-old female patient with auditory synaptopathy/neuropathy

Introduction Auditory synaptopathy/(AS/AN) is defined as a sensorineural hearing loss because of a disturbed synchronization of excitation of spiral ganglia neurons due to a dysfunction in either the inner hair cells, the ribbon synapses, postsynaptic dendrites, the spiral ganglion cells, the postsynaptic axons and/or the cochlear nucleus.

Methods We report a case of a 58-year old woman with bilateral progressive hearing loss due to AS/AN. Maximum perception score in the Freiburg monosyllabic test was 25% in the right and 20% on the left side. With optimal hearing aid fitting, the patient achieved a monosyllable understanding of 0% on both sides at 65 dB _SPL quiet. DPOAE were detectable on both sides. In the click-auditory brainstem response measure no stimulus-related potentials could be conducted on either side and no responses were observed in the ASSR. No stapedius reflexes could be elicited on either side. After cochlear implantation on the left side, the intraoperative audiological measurements showed proper impedances, but only limited detectable ECAP. Likewise, during fitting of the speech processor no ECAP could be detected up to the discomfort threshold. With defined suprathreshold stimulation using bipolar alternating intracochlear stimulation through the CI, the potential eJ3 could be recorded with a latency of 2.27 ms and the potential eJ5 with a latency of 4.17 ms, which corresponds to a longer latency compared to corresponding reference values. A perception score of 42.5% for monosyllables was achieved at 65 dB_SPL  in quiet 3 months after first fitting.

Discussion  Cochlear-implantation is a rehabilitation option for patients with AS/AN. In this case, there was gain in monosyllabic intelligibility.

Publication History

Article published online:
12 May 2023