Measuring Multi-Joint Upper Limb Proprioceptive Position Sense in Children with Unilateral Spastic Cerebral Palsy using 3D Kinematics

BackgroundProprioceptive position sense (PPS), which provides the awareness of the positions of ones limbs in space, is compromised in children with unilateral spastic cerebral palsy (USCP). Relationships between decreased PPS, skill acquisition, and performance are not well understood partly due to differences between measurement modalities of PPS. During assessments, individual joints are often constrained to a single plane of movement. We introduce ways to estimate PPS, simultaneously from multiple upper limb joints during unconstrained pose matching tasks, using 3D kinematics. MethodsNineteen children with USCP, 14 age-matched typically developing children (TDC) and, 16 typically developed adults (TDA) were recruited. Participants performed contralateral upper limb pose matching tasks while blindfolded. Using 3D kinematic data extracted by a VICON Nexus motion-capture system, three ways of measuring matching performance were calculated: joint angle symmetry, joint distance symmetry, and orientation symmetry. Mann-Whitney U tests were used to statistically compare scores between groups. Spearmans rank correlation was used to investigate relationships between PPS symmetry measures and hand function in children with USCP. ResultsChildren with USCP presented significantly lower angle, distance, and orientation symmetries compared to TDC. TDA scores were not statistically significantly different compared to TDC. In children with USCP, orientation symmetry measures strongly correlated with several clinical hand function scores such as the box and blocks test. ConclusionsWe introduced a new way to conveniently measure multi-joint PPS. Children with USCP presented lower PPS estimates compared to TDC. We also observed that orientation symmetry (limb co-ordination) strongly correlates with hand function.