Recovery of natural hearing after cochlear implantation in a case of ISSNHL

More than 80% of the affected 430 million people with disabling hearing loss suffer from sensorineural hearing loss._1,2 When the cause of the hearing loss cannot be determined, it is referred to as idiopathic sudden sensorineural hearing loss (ISSNHL). In the absence of response to standard therapy, the use of hearing aids or cochlear implantation is recommended.₂  We present a patient with unilateral ISSNHL who was treated with a cochlear implant and developed hearing threshold recovery 1 year after implantation. A 55-year-old man presented with acute left-sided hearing loss bordering on deafness, intermittent vertigo and numbness on the left side of the face. There was no improvement in the audiogram after coverage of the oval and round window. After 5 years with no further improvement, a cochlear implantation was performed. The patient then achieved speech intelligibility of 80% in the Freiburg monosyllabic test. Nevertheless, in 2021 he complained of pain and vertigo when using the cochlear implant. Audiometry showed a new hearing threshold of 25 dB from 250 Hz to 1 kHz with bone conduction, confirmed by objectiv testing. According to the literature, 21-28% of patients treated for ISSNHL make a full recovery.₃  Notably, patients with a more severe form of hearing loss showed a delayed recovery, so sufficient follow-up time (6 months) should be offered.₄  Interesting in our case is that the hearing has recovered after 7 years. It is unclear what caused the sudden improvement in hearing in this patient. Investigations with a small study population discovered a possible association between cochlear synaptopathy and full recovery after ISSNHL, suggesting a possible involvement of cochlear synaptopathy in the pathogenesis of ISSNHL.₃ 

1. World Health Organization. Deafness and hearing loss [Internet]. WHO; 2021 April 1 [cited 2022 November 10]. Available from: https://www.who.int/news-room/fact-sheets/detail/deafness-andhearing-loss 2. Plontke SK. Diagnostics and therapy of sudden hearing loss. GMS current topics in otorhinolaryngology, head and neck surgery. 2017;16(1865-1011). 3. Seo HW, Lee SY, Byun H, Lee SH, Chung JH. Possible Existence of Cochlear Synaptopathy in Patients Completely Recovered from Idiopathic Sudden Sensorineural Hearing Loss. J. Clin. Med. 2022;11(3). 4. Na G, Kim KW, Jung KW, Yun J, Cheong TY, Lee JM. Delayed Recovery in Idiopathic Sudden Sensorineural Hearing Loss. J. Clin. Med. 2022;11(10).

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Artikel online veröffentlicht:
12. Mai 2023