Cochlear implant: correlation of nerve function recovery, auditory deprivation and etiology

The Auditory Nerve Recovery Function (REC) may be extracted from the Electrically Evoked Compound Action Potential (ECAP). ECAP may be influenced by the stimulation received (or the deprivation of stimulation) and by the etiology of the hearing loss, consequently it might affect the REC.

To verify whether there is a correlation between the REC and each of the following factors: etiology, time of auditory deprivation and time of hearing aid use before cochlear implantation (CI).

Retrospective study. Data regarding etiology, time of auditory deprivation, time of hearing aid use before cochlear implantation were collected in children and adults who received a Nucleus®24. All patients who presented neural response at surgery and whose REC was assessed intraoperatively were included in this study. Fifty patients were selected, 26 children and 24 adults. Patients were divided according to the REC classification into three groups (GI: fast recovery; GII: intermediate recovery and GIII: slow recovery) to allow correlation analysis.

Data analysis did not show any statistically significant correlation between the recovery function and the pre-implant studied characteristics. Nevertheless, it was observed that there was a greater concentration of both, children and adults, in the intermediate recovery function values. GI did not present individuals with infectious etiologies, such as meningitis, rubella and cytomegalovirus. REC average scores were slower in infectious etiologies for both children and adults.

There was no statistically significant correlation between the recovery function and factors such as etiology, time of auditory deprivation and time of hearing aid use prior to CI.