We conclude with a brief and inconclusive examination of the ergonomic issues likely to be encountered with Thumbcode.
Among the health hazards real and imagined presented by computers, the keyboard features as a prominent offender. The author is as aware of these concerns as anyone, having had acute tendonitis in both elbows on different occasions in the distant past, apparently resulting from typing.
Thumbcode presents similar risks to regular keyboards, involving repetitive small motions.
Assigning the most comfortable thumb positions to the most frequently typed characters should not only improve typing efficiency but minimize stress on tendons, muscles, and joints. As noted earlier, the user can further reduce stress on tendons, joints, and muscles by finding the most comfortable positions consistent with reliable identification of thumbcodes.
One common recommendation with keyboards is to take breaks and give your hands a rest, or exercise them in some way different from typing. This is equally good advice for thumbing.
In conclusion, Thumbcode is a digital sign language carefully designed to accommodate the ongoing shrinking of wearable computers. Currently we have no experience with Thumbcode to justify our confidence in our design. However we hope in the near future to experiment with some of the devices suggested above for recognition of Thumbcode signing.