'Fitbits' to Keep Tabs on Body from Within

                Scientists are developing dust-sized wireless sensor implanted inside the body to track neural activity real-time, offering a potential new way to monitor or treat conditions including epilepsy and control next-generation prosthetics. The tiny devices have been demonstrated successfully in rats, and could be tested in people within two years. We can almost think of it as an internal, deep-tissue Fitbit, where you would be collecting a lot of data that today we think of as hard to access. Current technologies employ a range of wired electrodes attached to different parts of the body to monitor and treat conditions ranging from heart arrhythmia to epilepsy. The idea here is to make those technologies wireless. The new sensors, about the size of grain of sand, have no need for wires or batteries. They consist of components called piezoelectric crystals that convert ultrasound waves into electricity that powers tiny transistors in contact with nerve cells in the body. The transistors record neural activity and send the data outside the body to a receiver