A clinical case of a patient with an anomaly in the development of the inner ear and refractory stimulation of the facial nerve after a coronavirus infection and meningitis

Background. Thanks to the development of technology and new surgical approaches, it has become possible to perform cochlear implantation (CI) in patients with malformations of the inner ear. The experience of this type of rehabilitation has more than 15 years in Russian practice and more than 20 years in the world. Unfortunately, the COVID-19 pandemic has added not only one more cause of deafness, but also etiological factor of the complications. The purpose of this paper is to describe a clinical case of facial nerve stimulation (FNS) in a CI user with an inner ear malformation and a coronavirus infection complicated by meningitis. A clinical case demonstrating a combination of all these etiological factors of FNS has not been previously described in the scientific literature.

Aim. To describe a clinical case of FNS in a CI user with an inner ear malformation and a coronavirus infection complicated by meningitis.

Materials and methods. In 2017 4 years old patient underwent cochlear implantation on her right ear in Saint Petersburg Research Institute of Ear, Throat, Nose and Speech. In May 2022 the patient was admitted to the infectious diseases department of the medical institution with the diagnosis: coronavirus infection (confirmed), severe course; complication: purulent meningoencephalitis. After recovery, the patient complained of facial muscles twitching when using the speech processor of the cochlear implant. In order to correct the non-hearing sensation, the patient was sent to the Saint Petersburg Research Institute of Ear, Throat, Nose and Speech for rehabilitation in June 2022. During repeated fitting, it was possible to improve the reactions to sounds. Phoneme discrimination has improved. Positive dynamics was registered against the background of the changed settings. The average hearing thresholds using 3-phase stimulation were 42.5 dB. However, it was not possible to completely eliminate the FNS, and the compulsory settings of the speech processor did not allow the patient to achieve sufficient speech intelligibility.

Conclusion. Meningitis after CI can cause an increase in the transmittance of the inner ear tissues to electric current and, as a consequence, the development of the FNS. Modern technologies make it possible to rehabilitate such patients, including those with abnormalities of the inner ear. To increase the effecacy of rehabilitation, special coding strategies are used including the 3-phase stimulation.