SPATIAL SUMMATION OF PAIN FOR LARGE BODY AREAS,
Abstract
Spatial summation of pain was investigated using high intensity infra-red radiation. Cutaneous pain thresholds were determined for a total of eight subjects using apertures ranging from 1 sq. cm to 200 sq. cm on the face area, and 10 sq. cm to 1500 sq. cm for large body areas. Two methods of determining threshold - reaction time and method of constant stimuli - were utilized. Skin temperature at threshold was determined by a radiometric measuring device especially designed for use during skin heating with infrared quartz lamps. Values so determined were checked by a computer solution of skin temperature rise using the best available data on the optical and thermal properties of the skin and found to be in close agreement. Results indicate that final skin temperature at threshold varied from 39.3C to 46.7C depending on subject, size of aperture, and area of body irradiated. A significant lowering of final skin temperature at threshold for the larger area occurred for all subjects when comparing apertures 1 sq. cm and 3 sq cm on forehead and face areas, and apertures 10 sq. cm and 40 sq. cm on chest and back. A slight decrease in final skin temperature at threshold was generally noted for aperture sizes 5 sq. cm and 200 sq. cm on face areas but was not consistent for all subjects. When 40 sq. cm apertures were compared with full back and chest exposures, a higher threshold for the very large areas was obtained for three of the four subjects used. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1964
- Accession Number
- AD0615479
Entities
People
- D. Murgatroyd