Electrical Impedance as a Biomarker for Inner Ear Pathology Following Lateral Wall and Peri-modiolar Cochlear Implantation. Issue 5 (June 2019)

• Record Type: Journal Article
• Authors: Shaul, Chanan; Bester, Christofer W.; Weder, Stefan; Choi, June; Eastwood, Hayden; Padmavathi, K.V.; Collins, Aaron; O'Leary, Stephen J.
• Is Part Of: Otology & neurotology. Volume 40:Issue 5(2019)
• Publication Date: 2019-06
• Subjects: Biomarkers -- Cochlear implant -- Hearing loss -- Impedance; Otology -- Periodicals; Ear -- Diseases -- Periodicals; Skull base -- Surgery -- Periodicals; 617.8005
• DOI: 10.1097/MAO.0000000000002227
• Languages: English
• ISSNs: 1531-7129

Abstract

Abstract : Objectives/Hypothesis: Spikes in cochlear implant impedance are associated with inner ear pathology after implantation. Here, we correlate these spikes with episodes of hearing loss and/or vertigo, with a comparison between lateral wall and peri-modiolar electrode arrays. Methods: Seven hundred seventy recipients of Cochlear's slim-straight, lateral wall electrode (CI422), or peri-modiolar (CI512) electrode were investigated for impedance spikes. Impedance fluctuations were defined as a median rise of ≥ 4 kΩ across all intracochlear electrodes from baseline measurements taken 2 weeks after switch-on. Medical records were analyzed from 189 of the 770 patients. Results: The slim straight, lateral wall electrode was found to spike in impedance at a significantly higher rate than the peri-modiolar array (17% vs 12%). The peri-modiolar electrode tended to spike in impedance earlier than the slim-straight electrode. Impedance spikes were found to significantly correlate with medical events (hearing loss, vertigo, or tinnitus). Overall, in the "spike" group, 42 of 75 patients (56%) demonstrated a clinical event during the impedance spike, whereas 26 of 114 patients (22%) of the "non-spike" group had a clinical event. This significant difference existed with both implant types. Conclusion: These results demonstrate a small, but significant increase in impedance spikes in lateral wall electrodes, and support the relationship between spikes in cochlear implant impedances and postoperative inner-ear events, including the loss of residual hearing and vertigo. Monitoring cochlear implant impedance may be a method for early detection, and so the prevention, of these events in the future.