Comparison Between the TSA2 and the Medoc Pathway in Assessing Thermal Leg Sensitivity

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University of Delaware
Quantitative Sensory Testing (QST) is a method used to quantify somatosensory function in large and small nerve fibers to detect sensory loss (i.e., hypoesthesia, hypoalgesia) or sensory gain (i.e., hyperesthesia, hyperalgesia, allodynia) that may be associated with acute and chronic pain. A set of objective testing procedures that include both thermal and mechanical test stimuli are administered based on a protocol. Thermal stimuli are administered with the gold standard Medoc Pathway, a stationary and heavy piece of equipment, however, a new to the market portable Advanced Thermosensory Stimulator (TSA2) is now available for testing with many of the same functions as the pathway; however, it has not been tested in the lower extremity. The aim of this study is to evaluate the agreement in thermal testing between the two machines. This is a repeated-measures two group study with two test sessions one day apart (N=20). Thermal testing consisted of warm/cold detection and heat/cold pain. Statistical analyses include paired t-test for mean differences, Pearson’s correlation for agreement, intraclass correlation and coefficient alpha values, and Bland-Altman’s plots for differences between the measurements. Mean age for participants was 32 years (SD=14.3) and evenly split between men and women. The paired t-test revealed no significant differences between the TSA2 and Medoc Pathway. Pearson correlations show strong correlations for thermal pain on the TSA2 and Medoc Pathway. High alpha values were revealed on all tests conducted, except for warm detection. Bland-Altman plots reveal agreeable data for cold detection, cold pain, and warm pain. Warm detection displayed a distinct pattern where there were differences between the Medoc Pathway and TSA2 when temperature rose, which might account for the low alpha value for warm detection.
Quantitative sensory testing, Thermal testing, Thermosensory Stimulator (TSA2), Medoc Pathway