Clinical Case Study Review

Abstract

This manuscript describes a case in which, based on clinical observations, we hypothesize that a change in a cochlear implant recipient's electrode impedance and performance was attributed to a change in the recipient's physiology rather than a device failure. Of particular note was the finding that electrode impedances decreased after a period of nonuse of the implant as well as after steroid treatment. Retrospective single-subject case study review. Outpatient clinic. This paper describes outcomes for a 75-year-old male cochlear implant user. A change in electrode impedance and a decrease in speech recognition were addressed through cochlear implant programming, periods of nonuse of the implant, provision of steroids, and bilateral cochlear implantation. The primary measures of interest were serial assessment of electrode impedance and speech recognition. Secondary measures included assessment of implant stimulation levels and electrophysiologic responses. Electrode impedances decreased (improved) after a period of nonuse of the implant as well as after provision of steroid treatment. Recipient performance also improved but did not return to baseline levels. Atypical fluctuations in electrode impedance were observed with periods of CI use and nonuse. Additionally, after a 10-month period of constant fluctuation of electrode impedances with atypical morphology, electrode impedances stabilized to normal levels with a typical morphology within 3 days of steroid treatment. Given these observations, we hypothesized that the change in this recipient's electrode impedance as well as the decrease in this implant recipient's performance may be attributed to his physiology rather than to the device failure. Changes in electrode impedance accompanied by a decrease in this patient's performance were successfully addressed by a period of nonuse of the implant, provision of steroids, and an increase in the pulse width of the biphasic pulsatile signal used for stimulation. It should be noted that the results of this case are anecdotal in nature and may not apply to all cochlear implant recipients experiencing electrode impedance changes and/or deterioration in performance.