Provocative infrared testing in amputees

Previous studies suggest autonomic dysfunction in amputees, yet the methodology for testing this is problematic. The common techniques of sympathetic skin response and skin conduction response require soles, palms and digits, so we further investigated the use of quantitative InfraRed Telethermography (qIRT) to assess vasomotor (sympathetic) tone. In prior work, IRT demonstrates residual limbs of amputees are significantly cooler than contralateral intact limbs. This study investigates provocative IRT (pIRT) to assess sympathetic (vasomotor) responsiveness in residual vs. intact limbs of amputees. Eight volunteer subjects with unilateral lower limb amputations were enrolled in the study. IRT images of subjects were taken before and for 50 seconds after electrical stimulation (15 mA for 0.1ms) at glabella. The qIRT Indigo® software was used to show average temperature of specified areas (last intact joint distal, compared to a similar polyhedron on the contralateral side). Consistent with previous findings, the results showed that residual limbs and intact contralateral limbs of amputees are significantly different in temperature. However, no significant change in temperature (Celsius) could be detected at any time interval after provocation. This indicates pIRT is not suitable for the assessment of sympathetic nervous system (vasomotor) function in this model. (Harden, Gagnon, Gallizzi, Khan, Newman; Pain Practice, 2008.) This study was supported in part by Endo Pharmaceuticals.