title: Effects of hyperbaric exposure on the integrity of the internal components of commercially available cochlear implant systems.
abstract: OBJECTIVE
  This study investigated whether pressure changes common to scuba diving and to hyperbaric oxygen therapy would not cause crush damage or leakage from critical seals in commercially available cochlear implants.
  
  
  BACKGROUND
  The implanted packages of cochlear implants are susceptible to electrical failure caused by leakage from critical seals and to crush injury when exposed to changing barometric pressures encountered in recreational diving and in hyperbaric oxygen therapy.
  
  
  METHODS
  Six Clarion 1.2, eight MED-EL Combi-40+, six Nucleus CI22M, and six Nucleus CI24M cochlear implants underwent three exposures at 165 feet of seawater (FSW) (6 ata abs), 99 FSW (4 ata abs), and 60 FSW (2.8 ata abs), simulating rates in accordance with U.S. Navy dive tables for nondecompression dives. Dives to 45 FSW (2.4 ata abs) simulated wound therapy. Before each dive began, after each dive, and after completion of the dive protocol, each device underwent telemetry and electrical integrity checks. All implants were returned to their respective factories for final electrical and quality control testing.
  
  
  RESULTS
  All 26 devices completed the dive protocol. One Nucleus CI24M implant had a fault recorded at electrode lead 18 on predive and final product testing, which was absent during interval dive measurements. All 26 devices passed final electrical and quality control testing. In addition, the six Clarion units passed repeat helium leak testing.
  
  
  CONCLUSIONS
  The implanted components of the Clarion 1.2, MED-EL Combi-40+, and Nucleus CI22M and CI24M were safely subjected to repeated pressure changes up to 6 atm abs, equivalent to 165 feet of seawater, without electrical failure from leakage at critical seals or crush damage.
authors.affiliation: The Listen for Life Center at Virginia Mason, Virginia Mason Medical Center, 1100 Ninth Avenue, X10-0N, Seattle, WA 98111, U.S.A. otoddb@vmmc.org
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Backous
authors.forename: Richard G
authors.initials: RG
authors.lastname: Dunford
authors.forename: Phil
authors.initials: P
authors.lastname: Segel
authors.forename: Mag Christine
authors.initials: MC
authors.lastname: Muhlocker
authors.forename: Paul
authors.initials: P
authors.lastname: Carter
authors.forename: Neil B
authors.initials: NB
authors.lastname: Hampson
mesh_terms: D003054:Cochlear Implants; D004242:Diving / Q000009:adverse effects*; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D008422:Materials Testing; D011312:Pressure