Thermal temporal summation has good reliability in the lumbar region.

Abstract

Objectives: Temporal summation (TS) via a thermal stimulus is a form of dynamic quantitative sensory testing that is often used as an indirect measure of central sensitization. While TS is frequently used as an outcome measure to assess the effectiveness of various interventions, the reliability of this measure has yet to be fully assessed in the lumbar spine. Therefore, the primary purpose of this study was to determine the test-retest reliability of TS using a thermal stimulus at the lumbar spine (LS). The secondary purpose was to compare the thermal TS values in the LS to that of the tibialis anterior (TA) and the thenar eminence (TE).

Methods: Adults with no activity limiting pain conditions between the ages of 18 and 40 were recruited to participate in this study. TS was measured following a series of heat-pulses administered by the Medoc Thermal Sensory Analyzer-II system. After undergoing an optimization session, TS was taken at the LS, the muscle belly of the TA, and the TE, all on the right side. A second thermal TS measurement was taken once again a week later.

Results: A total of 25 (n = 11 female) individuals participated in this study. ICC values in the lumbar spine ranged from moderate to good (0.591 to 0.836) depending on the calculation method. This compared to the TA with ICC values ranging from 0.621 to 0.772 and the TE with values ranging from 0.572 to 0.751. Correlations of the thermal TS values were high between the LS and the TA (r = 0.745), moderate between the TA and the TE (r = 0.631), and weak between the LS and the TE (r = 0.443).

Discussion/conclusion: Thermal TS taken at the LS is a reliable measure with ICC values that are comparable to ICC values found at the TA and the TE.