The pilot study focused on the effective design of adaptive biofeedback equipment for use in the control of self-mutilating behaviors in individuals with Lesch-Nyhan syndrome, typically characterized by apasticity, mental retardation, and violent biting of the lips and fingers. Utilizing an electromyographic (EMG) monitor and a custom-designed relay connected to either a computer game or a tape player, a 15-year-old male learned to control sudden high levels of arousal-related muscular tension which were the antecedents of self-abuse. A subsequent study of the experimental treatment protocol (rather than the viability of the instrumentation) is proposed. (Author/JW)