An overview Adam McCullough – Group 10

Computers are unparalleled problem solvers. The fact that they are growing smaller, cheaper, and requiring less power means that the scope and type of problems they can now be applied to is changing by the minute. One of the biggest problems computer science is trying to solve – or at least change – is medicine. Several companies are utilizing both existing and developing technology to provide health monitoring services in the home.

This allows many game-changing services:  Personal, portable monitoring of vital signs  Immediate notification in case of a medical emergency  Recording of vitals over time, to allow the tracking of therapy or treatment progress  Broad-scale data mining:  Tracking a flu epidemic the same way one tracks the spread of a worm or virus on a network: node by node.  Open up a whole new wealth of information for statistics, analysis, and research.  And much more. The general agreement is that we've just barely scratched the surface of what's really possible. [2] [1]

This also allows many new, unseen hazards:  Broadcast of personal health information over one or more networks  ‘Immediate notification’ may be making an impossible service guarantee  Broad-scale data mining!  Insurance company could decide to cut coverage right as a customer needs it  Research, or Big Brother?  Etc…

The Digital Tattoo is a conceptual design put out by Jim Mielke at the Greener Gadgets Design Competition 2008 [4] Basic facts :  Surgically embedded just beneath the skin.  LCD Touchscreen – invisible when off, easy to use when on.  It runs off of glucose and oxygen – If you’re running, it is.  Has Bluetooth networking support, and is designed to network both with devices within and without the users body.  Designed to be an always-on monitor for various blood disorders and vital signs

This technology would give both doctors and patients unprecedented access to medical information, such as heart rate, BAC, blood sugar level, and so on. This would normally require either invasive procedures or dedicated hardware to obtain/record this information. It also allows for the next level of contingency planning – if your vitals take a nose dive, this would be able to send an emergency notice out in an attempt to get paramedics on the scene.

However, this is not a new idea, just a new way to do it.. Many studies have already been done on the concept, and they’ve identified some basic limitations:  Power. Running on glucose guarantees an always-on (we hope!) power supply, but it does not necessarily generate a lot.  However, this particular application does not need a lot of processing power, nor does it need to move around a lot of data, comparatively speaking. Blood Pressure is not likely to change drastically over one Mhz!  This makes Bluetooth a sub-optimal choice. ZigBee is an alternative physical layer which is specifically designed for low data, low duty-cycle tasks.

 It needs to be reliable – 24/7/365.  Another possible energy source could be the patients movement. Work is being done on exploiting human movement as a readily available energy source. [5]  The low power availability also means that the tattoo won’t be able to connect to a global network itself – it will need either a cell phone, computer, or some other ‘personal wireless hub’ to act as a router.  ‘Smart house’ networks – houses that use ZigBee, Bluetooth, or wifi to control things like lights, thermostats, and so on would be ideal for this. [3]

This example is from a research paper [3]. The example expects the sensors to be external to the body, and connect to a specialized PWH. However, the concept can be generalized very easily.

This also highlights two different possible architectures – 1: Have the sensors integrated directly into the tattoo. This eliminates the need for a (medical) BAN, but puts more processing weight (and therefore more power draw) on one device. 2: Have the tattoo act as a router between several different, networked internal sensors and a Personal Wireless Hub (computer, house network, cell phone, etc.) This makes the overall design more generic and less centralized, but also opens up a possible security hole in the inter-sensor network.

This kind of network approach would allow the Digital Tattoo (paired with some form of PWH) to send an emergency notification to a hospital, paramedics, and so on if any of your vital signs go critical. What happens if the patient forgets or goes out of range of his PWH, and has a medical emergency?

One solution is to have the device send out a broadcast-like message to any device in range to send a message out to the proper destination (health care providers, paramedics, etc). It doesn't matter how the information arrives – just that it arrives. This does open up a rather huge privacy gap, however. Another would be to have the tattoo alert the user if he goes out of range.

 Security. This device has access to your vitals, medical history, what chemicals and substances you prefer, and so on. This is not public domain!  Possible solutions include heavy encryption, the limited range of the wireless protocols in use, and so on. [3]  Like all security options, the solutions are robust, but not full proof.  They also do not address the largest security hole: The user!

References: [1] [2] [3] [4] [5]

Questions?