Are there any concerns regarding a cochlear implant patient that needs an MRI of the knee due to a sport injury?
A MRI scanner utilizes a powerful magnetic field to image parts of the body. Regardless of what part of the body is being viewed (e.g. the knee), the whole body is exposed to the magnetic fields generated by the MRI scanner when a patient is in the imaging room. The magnetic properties of an MRI machine can potentially cause harm to a cochlear implant device and the user.
Newer cochlear implant devices have become available in recent years which allow removal of the magnet prior to an MRI. This requires a procedure with a small incision to remove the magnet from the subcutaneous portion of the implant resting behind the ear before MRI completion; a similar procedure is performed to replace the magnet to allow resumption of implant use after MRI. Magnet removal makes it safe for an implant recipient to have an MRI up to 1.5 Tesla in strength (a measure of magnetic field). Although some studies have suggested it may be safe for cochlear implant patients to undergo MRI with fixed (non-removable) magnets, especially in weaker strength MRI scanners (e.g. 0.2 Tesla), this has not been accepted for general use in the United States. A cochlear implant recipient should always consult with their implant surgeon before any imaging is performed, regardless of the imaging technique.
Lance E. Jackson, MD is an Otologist/Neurotologist and president of the Ear Institute of Texas in San Antonio, TX. Refer to his web site www.earsoftexas.com for a list of publications.
This article discusses issues surrounding hearing preservation with cochlear implantation surgery. This discussion includes factors that may affect hearing preservation with traditional cochlear implant devices as well as a discussion of research findings with hybrid/EAS devices. Editor's note 10/7/11: There have been rapid changes in the field of cochlear implantation thanks to ongoing advances in research and technology. Just since this article has been published, there are some very recent developments in EAS research at the University of Iowa. In the last three months, they have been given FDA approval to conduct two feasibility trials to study preservation of hearing with Nucleus hybrid cochlear implants in those with severe hearing loss and will be implanting children between the ages of 5 and 15 years of age. This new information about the Iowa-sponsored feasibility trials contradicts two points within questions 15 to 18 of the article: Adults with greater hearing impairment than those in the clinical trial described in the article are eligible for implantation with a Nucleus Hybrid L24 implant through the Iowa-sponsored feasibility trial, and the S12 and L24 devices are available to children through the feasibility study at the University of Iowa. Please keep this is mind as you read the article. As new advances are made in this exciting area of research and practice, we will try our best to keep you informed!
This course details diagnosis of enlarged vestibular aqueduct and theories of hearing loss. Audiologic presentation, progression of hearing loss and rehabilitative options will be reviewed.
Please note: You may earn ABA Tier 1 credits for this course if you complete it as part of the course 26683, "Advanced Management of Complex Cases." Course 26683 contains recordings of all three events from Advanced Bionic's 2015 series, Advanced Management of Complex Cases. ABA Tier 1 CEUs can be earned only when all modules are completed as part of course 26683.
This modular course explores various aspects of managing advanced cases involving children with cochlear implants. The first component discusses Usher Syndrome and its relevance to newly identified children and their families. The second section details diagnosis and audiologic treatment and rehabilitative options for children with enlarged vestibular aqueduct. The third section discusses caveats regarding cochlear implant candidacy in medically complex children.