The tape will have an area no greater than a standard four-by-four-inch medical pad, with a minimum of a one-inch bend radius, making it small and lightweight. The suite of sensors on the tape will include accelerometers; pressure, acoustic, and light sensors; and a thermometer. "One reason for measuring all these [parameters] is that no one is certain which one, or which combination, will best act as a proxy for the harmful brain injury that results from accumulated blast exposure," says Jennifer Ricklin, DARPA program manager for the Sensor Tape Program.

One "alarming issue" is that "soldiers are sustaining repeated exposures [to blast events] when they may not be recovered from the first one," says Robert Cantu, a neurosurgeon at Emerson Hospital, and a professor of neurosurgery at Boston University School of Medicine. "This can lead to second impact syndrome, which is fraught with a 50 percent mortality rate, or permanent post concussion syndrome, which is basically persistent concussion symptoms." ("Concussion" is the medical term for mild traumatic brain injury, and symptoms can include headaches, sleep problems, depression, and memory and concentration difficulty.)

Data from the sensor tape will be extracted and stored with the soldier's medical records using a device (not yet built) that makes it easy for a soldier's full blast history to be displayed and analyzed. "Cumulated blast exposure should be recorded such that if these exceed a prescribed level, the patient could be flagged for appropriate follow-up evaluation," says Ricklin. She expects to have 25 prototypes to test the components by spring 2009, and 1,000 prototypes for field testing by 2010.

The DARPA program, which is in its initial stages, is focused on the interaction between IEDs and the neurological system, to determine what is most likely to cause neurological injury. "The sensor tape is an important and badly needed technology to get at that data," says Parker.