Stability of paraspinal thermal patterns during acclimation

Background: Paraspinal thermography has been used by chiropractors since 1924. One method of its interpretation is with the use of "pattern analysis"-a method that assesses temperature differentials (patterns). This, in turn, theoretically provides information about nervous system function. When a warm back is exposed to the cooler air in the examining room, the skin temperature, in general, drops but the differentials could remain fairly constant. Objective: To determine what changes occur in paraspinal heat patterns when the back is exposed to room temperature. Study Design: Observational; measures repeated at 5-minute intervals for 31 minutes. Methods: Thirty subjects were scanned with digital infrared thermographic instrumentation every 5 minutes over a 31-minute period for a total of 7 readings per subject. A computerized calculation of percent similarity between consecutive comparisons of the readings was then performed to determine if and when the pattern stabilized. Results: Cervical spine temperatures remained relatively constant while lower back temperatures, in general, decreased for the entire 31-minute recording period. Although the results varied among subjects, on the average, the patterns stabilized after 16 minutes. Conclusions: Once the patient's back is exposed to cooler room temperature, the skin temperature decreases constantly for 31 minutes; however, the pattern becomes stable after 16 minutes. Readings taken for the purpose of pattern analysis during this 16-minute period may be unreliable for some patients. Therefore, a 16-minute acclimation period is recommended. Further research is needed to not only verify this finding with the same equipment in a separate experiment but to verify it as well with other types of temperature instrumentation.