Thermal thresholds in complex regional pain syndrome type I: sensitivity and repeatability of the methods of limits and levels

Objectives: To study whether the method of levels (MLE) or the method of li mits (MLI) is preferable as a method of measuring thermal perception thresh olds in patients with complex regional pain syndrome type I (CRPS I). Methods: Perception thresholds fur warmth and cold were measured twice, wit h both MLE and MLI, at a 1 month interval, both at unaffected and affected wrists (n = 33) or feet (n = 20) of patients with CRPS I of one extremity. Results: (1) Sensitivity for pathology was equal for both methods. (2) The agreement between thresholds measured by both methods was low at all locati ons, except for the unaffected wrist. Since thresholds measured with the ML I always contain reaction time artefacts, this lack of agreement favours th e MLE. (3) At both unaffected and affected wrists, the: MLE showed signific antly better coefficients of repeatability as compared to the MLI for both sensations. However, at both unaffected and affected feet, there was no pre ference for either method as far as threshold measurement repeatability was concerned. Conclusions: Abnormal thermal perception thresholds occurred in 20% (foot) to 36% (wrist) of the CRPS I patients on the affected side and in 15% (foot , wrist) On the unaffected side. The MLE is considered to be the preferable method to assess thermal perception thresholds in CRPS I. (C) 2000 Elsevie r Science Ireland Ltd. All rights reserved.