Cutaneous sensory threshold stimulation with high frequency square-wave current. II. The relationship of body site and of skin diseases to the sensory threshold.

Potelunas, Meixner and Hardy (1) suggested the possibility that the pain threshold was not uniform in all areas of the body when they found wide variation in such thresholds in normal and pathological skin. Bishop (2) reported that the number, distribution and accessibility of the sensory receptors of the skin varied in different areas. The cutaneous sensory threshold was shown by the author (3) to be influenced by the number, distribution and accessibility of the sensory receptors. The effect of syphilitic lesions on the sensibility of the skin was studied by Ollendorf (4) and by Mayr (5) both of whom found increased sensitivity in the lesions. The study of pain thresholds with thermal radiation in diseases of the skin by Potelunas, Meixner and Hardy (1) revealed that 1) the pain threshold tends to remain unaltered by skin disease, 2) raised pain thresholds were caused by thickened skin and 3) hyperexcitability of the superficial pain endings may account for lowered pain thresholds. The following investigation was undertaken to study the relationship of body site and of diseases of the skin to the cutaneous sensory threshold by means of the high frequency square-wave current. The apparatus and the basic principles for the use of the square-wave current are described in previous reports (3, 6).