Test Order for Quantitative Sensory Testing (QST) and its Impact on the Test Outcome

Objectives: Quantitative Sensory Testing (QST) is a group of various sensory tests used to evaluate the sensory function of large and small nerve fibers. In this study, we evaluated the mechanical, heat and cold induced pain thresholds for six QST test sequences on two different testing sites i.e. Dominant volar forearm and Infra orbital region.
Methods: A total of 29 healthy subjects aged between 18 and 75 yrs were recruited. Subjects underwent QST testing at two different time points, one week apart. Each testing session was randomly designated to one of the testing sites; Dominant volar forearm or Infra orbital region.
Results: No statistical difference was observed between the QST test sequences for the mechanical and heat induced pain threshold for the infra orbital region (trigeminal system) as well as for the dominant volar forearm (extra trigeminal system). A significant difference was observed between the QST test sequences for the cold induced pain threshold in the infra orbital region (trigeminal system) as well as for the dominant volar forearm (extra trigeminal system). Regardless of the sequence order performed, the cold induced pain testing results are altered if done after the heat sensory testing.
Conclusions: The results of the study suggest to performing cold induced pain test before heat pain threshold test while performing QST.