Changes in Digital Skin Temperature, Surface Electromyography, and Electrodermal Activity in Subjects Receiving Network Spinal Analysis Care
Eric B. Miller, Ph.D., Peter D. Redmond, D.C.
Journal of Vertebral Subluxation Research ~ Volume 2 ~ Number 2 ~ Pages 1-9
A preliminary study was conducted to evaluate changes in digital skin temperature (DST), surface electromyography (sEMG), and electrodermal activity (EDA) in a group of twenty subjects receiving Network Spinal Analysis (NSA) care. Data, simultaneously derived from all three parameters, were considered to be indirect correlates of sympathetic nervous system activity. Subjects, including a group of five controls, were assessed for a period of 17 minutes. The continuous assessment period included a baseline interval of 4.5 minutes, followed by a 12.5 minute period which was divided into five 2.5 minute intervals. Care was administered to the NSA recipient group immediately after the baseline period, whereas controls received no intervention following baseline. Results revealed no significant differences in DST either within or between the two groups. Surface EMG readings were relatively constant over the five intervals following baseline in the NSA group, while controls showed significant (p < 0.05) increases in sEMG at the second through fifth intervals relative to the first interval following baseline activity. Electrodermal activity was significantly decreased (p < 0.01) in the NSA group in the second through fifth intervals compared to baseline. Moreover, decreases varied between intervals, but exhibited a leveling from the third through fifth interval. Control subjects, alternatively, exhibited an increase in EDA in all intervals following baseline. The extent of increase resulted in EDA activity significantly greater than the NSA group at the third through fifth intervals. It was concluded that the increase in EMG activity in the control groups may have reflected an increasing level of anxiety due to the duration of the recording period. Since the NSA group expressed constancy in sEMG activity during the same period, coupled to significant decreases in EDA, a “sympathetic quieting effect” was postulated to occur in subjects receiving NSA care. This conclusion is consistent with hypothesized neurological pathways linked to responses observed during NSA care, as well as other reports of self-reported improvements in mental/emotional state and stress reduction in patients receiving Network Chiropractic Care.
Key words: Network Spinal Analysis, vertebral subluxation, sympathetic nervous system digital skin temperature, surface electromyo-graphy, electrodermal activity