Bluetooth's ubiquity is both a blessing and a curse. A wireless system might work well using this wireless protocol in some situations if no one else is around but may be less reliable "if someone is sitting next to you with their Bluetooth headset on," says Mike Dempsey, a senior research and development engineer at the Center for the Integration of Medicine and Innovative Technology (CIMIT), a consortium of Boston teaching hospitals and engineering schools. "This is the reason that the medical industry needs to advocate for dedicated spectrum."
Body Sensor Network Bandwidth
Healthcare providers and technology companies are pushing the U.S. Federal Communications Commission (FCC) to allocate a dedicated piece of the wireless spectrum for secure, reliable transmission of patient data. The FCC is taking this request to heart and in August began soliciting comments from the public that will help the agency determine which portion of the spectrum, if any, is needed to protect MBANs from potential interference from unlicensed mobile devices or other interference. The comment period is expected to last 90 days, after which the FCC could make a decision.
"We're working to get some spectrum set aside to help us advance low power wireless sensors that could go on the body and replace wired sensors today," Freeman says, adding he is hopeful the allocation could happen by the end of the year.
The FCC has allocated spectrum for medical devices in the past. In 2000, the agency cleared space for the Wireless Medical Telemetry Service (WMTS) that allows potentially "life-critical" equipment such as heart, blood pressure and respiration monitors to wirelessly transmit patient measurement data to a nearby receiver on an interference-protected basis. Prior to this, medical telemetry devices had been operating unprotected from interference either on vacant TV channels or on special channels reserved for low-power operation.
Since the WMTS does not have a lot of bandwidth, this piece of spectrum is reserved for only the most important signals (such as heart rate and breathing) data. This excludes sensors collecting and monitoring less critical, though still key, data, such as blood glucose levels, body temperature or pulse oximetry (the oxygenation of a patient's hemoglobin), from the WMTS.
MBANs at Home
If all goes well, look for MBANs to fall into three categories in the near future—those used to monitor a patient's general health or "wellness," those measuring the health of the elderly, and those used to monitor patients with long-term medical conditions such as Parkinson's disease or epilepsy, says Paolo Bonato, director of the Motion Analysis Laboratory at Boston's Spaulding Rehabilitation Hospital and an assistant professor of physical medicine and rehabilitation at Harvard Medical School.. He also served as chair of the IEEE Engineering in Medicine and Biology Society (EMBS) Technical Committee on Wearable Biomedical Sensors and Systems in 2008.
Bonato is watching the MBAN space with special interest, since his work focuses on technology in rehabilitation for disabled people, in particular on wearable technology and robotics. As MBAN technology matures, it might also be used to address the needs of the world's aging population and problems with healthcare costs by allowing patients to be monitored remotely (yet unobtrusively) while at home. "Some conditions could be monitored in the field," he says. "We can't put everyone in medical facilities."