Speech Audiometrical Results Before and After Reimplantation of Cochlear Implants

This study aimed to compare the audiological outcomes of cochlear reimplantation with those of the first cochlear implant (CI).

A retrospective analysis was performed on the data of all CI recipients who received the first CI at the age of 8 years or above and who were subsequently reimplanted on the same side. All participants who received their first implant after January 1, 2000, and who were reimplanted before January 1, 2021, were included. CI recipients who were unable to perform an open-set of Flemish monosyllable speech audiometry were excluded. The participants' clinical files were reviewed in terms of the cause of hearing loss, age at the first and second implantation, device types, the time between the first and second surgery, speech reception scores before and after reimplantation, and the reason for reimplantation.

Reimplantation was due to device failure in 19 out of 22 patients, performance decrement in two patients, and medical reasons in one patient. The interval between the first and second CI ranged from 8 to 218 mo. Within-subject analysis showed the speech reception performance with the second CI to be significantly better than that with the first CI at all follow-up time points, with average within-patient gains of 17%, 16%, 12%, and 15% at 3 mo, 9 mo, 3 years, and the highest scores achieved, respectively. After reimplantation, the performance was better than the last results before reimplantation, and this was significant from 9 mo after reimplantation onwards. Three patients (14%) had a performance degradation with the second CI, which was probably owing to (1) difficulties in reimplantation surgery leading to a reduced number of active channels, (2) insufficient experience with the second CI as the reimplantation has been performed recently, and (3) advanced fenestral and retrofenestral otosclerosis.

The present study shows that speech reception performance after reimplantation yields faster and better results than the first implant. It takes a couple of months to get better results than those before the reimplantation. Only in a minority of participants, a small deterioration may be observed. It seems that soft failures in the absence of measurable technical abnormalities call for caution with regard to reimplantation.