Measuring Behavior 2005: Schasfoort et al.

Objective and continuous measurement of limited mobility and/or limited upper limb activity

F.C. Schasfoort, J.B.J. Bussmann and H.J. Stam

Department of Rehabilitation Medicine, ErasmusMC, Rotterdam, The Netherlands

Our research aims at the development, validation and application of ambulatory monitoring devices that allow objective, continuous, and long-term measurement of activity of healthy and disabled subjects. Two instruments, based on ambulatory accelerometry, were developed: the Activity Monitor (AM) and the Upper Limb-Activity Monitor (ULAM). Both instruments consist of body-mounted uni-axial piezo-resistive acceleration sensors connected to a portable waist-worn data recorder. Data are stored digitally and downloaded onto a computer for automated kinematic analysis after the 24-48h measurements, based on Signal Processing and Inferencing Language (SPIL) routines. The AM allows objective measurement of the mobility-related activities lying sitting, standing, walking, cycling, and general (non-cyclic) movement, and can be used to determine (limitations of) mobility. The ULAM allows objective measurement of activity of both upper limbs during performance of these mobility-related activities, and can be used to determine activity limitations in subjects with upper limb disorders. The primary ULAM outcome measures are the intensity, percentage, and proportion of upper limb activity during sitting and standing.

We will describe the development and validation of the ULAM. Secondly, we will illustrate its applicability by showing the results of several studies with the ULAM in patients with unilateral upper limb Complex Regional Pain Syndrome type I (CRPSI), with measurements performed in the subjects’ natural environment. One study compared objectively measured ‘24-h ULAM activity profiles’ of ten chronic CRPSI patients with ten healthy comparison subjects. Mainly the patients with dominant side CRPSI had significantly limited intensity, percentage, and proportion of upper limb activity when compared to healthy subjects. The second study in thirty chronic CRPSI subject showed that grip strength and limited active range of motion of wrist and fingers were the most important CRPSI-related impairments explaining variance in activity limitations. Another longitudinal study in acute CRPSI showed that the ULAM could validly assess upper limb activity over time, and can therefore be used in future treatment efficacy studies in upper limb CRPSI.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.