The researchers led by the Medical University of Hanover, in Germany, find the 3T MRI machine can demagnetize the patient's implant. They recommend MRI scans on patients with cochlear implants be performed using a 3T MRI machine only if a 1.5T machine isn't available and if the benefits of the scan far outweigh the risk of cochlear implant demagnetization.

The study, conducted by a team of German and U.S. physicians and published in Otolaryngology -- Head and Neck Surgery, tested cochlear device magnets on a 3T MRI scanner with active shielding at a variety of angles and found routine use of 3T MRI machines at angles above 80 degrees can cause permanent damage to non-removable magnets.

The cochlear implant -- a surgically implanted electronic device activated by a device worn outside the ear -- restores partial hearing to the profoundly deaf. The implant doesn't make sound louder or clearer but bypasses damaged parts of the auditory system to directly stimulate the hearing nerve. MRI devices use magnetic and radio waves to produce detailed pictures of body tissue.