The Effect of Steroids on Cochlear Impedance in Humans: A Systematic Review

Objective: – To review the effects of perioperative steroid delivery on cochlear impedances in human patients. Data bases reviewed: – PubMed, Web of Science, Embase, Ovid, and Cochrane databases were reviewed from inception through March 2025. Methods: – The Preferred Reporting Items for Systematic Reviews (PRISMA) reporting guidelines were used. Studies comparing cochlear impedances among patients who underwent cochlear implantation either with or without perioperative steroids were included. Data were collected on method, timing, and dose of steroid administration and cochlear impedance in the perioperative period. Results: – Twelve studies were included in the review, which described 4 different routes of steroid delivery: intratympanic (3), intracochlear (7), drug-eluting electrodes (1), and intravenous±oral steroids (1). Nine studies revealed a significant association between steroid use during at least one point in the perioperative period to include 2 intracochlear studies and the intravenous±oral steroids study. Intratympanic steroid delivery reduced impedances up to 6 months postoperatively, whereas intracochlear and drug-eluting electrodes had persistent reductions in impedance up to 1 year. There was significant heterogeneity in study outcomes that limited the ability to perform a meta-analysis. Conclusions: – Based on studies meeting inclusion criteria, local delivery of steroids via intratympanic, intracochlear, and drug-eluting formulations appear to lower cochlear impedances for a variable duration postoperatively. Oral steroids do not appear to affect cochlear impedances postoperatively. More studies are necessary to further elucidate the relationship between steroids and cochlear impedance.