Electromagnetic compatibility of implantable neurostimulators to RFID emitters

Six active implantable neurostimulators with lead systems were tested for susceptibility to electromagnetic fields generated by 22 RFID emitters. These medical devices have been approved for marketing in the U.S. for a number of intended uses that include: epilepsy, depression, incontinence, Parkinsonian tremor and pain relief. Each RFID emitter had one of the following carrier frequencies: 125 kHz, 134 kHz, 13.56 MHz, 433 MHz, 915 MHz and 2.45 GHzThe test results showed the output of one of the implantable neurostimulators was inhibited by 134 kHz RFID emitter at separation distances of 10 cm or less. The output of the same implantable neurostimulator was also inhibited by another 134 kHz RFID emitter at separation distances of 10 cm or less and also showed inconsistent pulsing rate at a separation distance of 15 cm. Both effects occurred during and lasted through out the duration of the exposure.The clinical significance of the effects was assessed by a clinician at the U.S. Food and Drug Administration. The effects were determined to be clinically significant only if they occurred for extended period of time. There were no observed effects from the other 5 implantable neurostimulators or during exposures from other RFID emitters.In the last several years, radio frequency identification (RFID) technology has become a popular choice for tracking people, animals, products and goods. This type of technology serves the same purpose as bar coding systems and magnetic strip systems, which is to provide identification. One advantage of RFID technology versus other types of technologies is the proximity for identification. Another advantage is the information stored in such systems can be programmed and reprogrammed, providing a robust way to store information. For example, bar code scanners (readers) need direct line of sight to identify barcodes. In magnetic strip technology, the magnetic strip cards have to be swiped through or very close to the reader to be identified