Let's get rid of all the wires! Consider an EEG brainwave scanner device such as the NeuroSky or Muse models available today. We can remove a great deal of complexity by simply modulating the measured data on different color LEDs which blink out their data as serial streams. Then to observe the data we simply point a camera at the LEDs and use software to pick out the data streams.
This approach could also be used for ECG, EKG, temperature, even internal body implants used for measuring tumor radiation and the like. The data from the body is slow enough that video can capture it since video has better bandwidth than body signals. By placing a few reference LEDs or orienting the camera the same way always, the task of picking out the various data streams becomes simple enough to readily accomplish in Processing or some other programming language.
Such a technique must be known and explored, so I wonder why it is not available in practice.