In the adult case presented, inhibitory casting proved successful in decreasing the positive support reaction. When casting was discontinued, the positive reaction returned. To provide a long-term solution for this problem, a polypropylene tone-inhibiting AFO was fabricated. It incorporated the same principles as the casts. The success achieved with casting was rapidly regained and then surpassed with the use of the tone-inhibiting AFO. Natural recovery might be cited by some as the cause for improvement in the patient presented. However, the loss of improvement during the interval between the removal of the inhibitory casts and the initiation of the use of the tone-inhibiting AFO demonstrates that the casting and the position provided by the casts had a positive effect on our patient. This notion is further supported by the fact that our patient still required use of the tone-inhibiting AFO as late as March 1980. We have no explanation for the rapid improvement following the cranioplasty. Suggestions for further research would include a similar study with a larger number of subjects and the use of cinematography and kinesiological EMG during walking with and without tone-inhibiting casts and orthoses to determine the effect of the devices on spastic muscle groups and gait patterns.