Objective Measurement of Activity Limitations in Complex Regional Pain Syndrome Type I; Development and Application of an Upper Limb-Activity Monitor

textabstractComplex regional pain syndrome type 1 (CRPS1) often leads to serious activity limitations in everyday life. To date, however, limitations in patients with CRPS1 of an upper limb have not been objectively measured.Therefore, the aim of this study was to develop an upper limb-activity monitor (ULAM), and to determine the applicability of the ULAM. Because the ULAM is relatively new and its measurement technique clearly differs from what is commonly used in research and clinic with respect to several methodological and practical criteria, we studied how the ULAM outcome measures were related to four questionnaires that also aim to assess the functional consequences of diseases. It was concluded that the current ULAM has the potential to validly assess upper limb activity over time in upper limb CRPSI. In ten female chronic CRPS1 patients and ten healthy control subjects, 24-h activity patterns were measured with the ULAM. This ULAM consists of body-fixed acceleration sensors, connected to a recorder worn around the waist. The ULAM automatically detects upper limb activity during mobility-related activities. Several outcome measures related to general mobility and upper limb usage were compared between patients and controls. The results showed that CRPSI in the dominant upper limb had modest impact on general mobility; i.e. on the percentages spent in body positions and body motions and on mean intensity of body activity. For upper limb usage outcome measures during sitting, there was a marked difference between CRPS1 patients and controls. Especially patients with dominant side involvement clearly showed less activity of their involved limb during sitting, indicated by significant differences for the mean intensity (P=0.014), percentage (P=0.004), and proportion (P=0.032) of upper limb activity. It is concluded that these ten chronic CRPS1 patients still had limitations in upper limb usage during everyday life, 3.7 years (average) after the causative event