Abstract
Our aim was to assess three-dimensional kinematic motion analysis as an objective diagnostic tool for the characterization of the movement disorder of Shivers in horses. Kinematic parameters were measured in three horses with Shivers and were compared with a control group of four normal horses. Multiple parameter differences were found in the horses with Shivers at the walk, during backing, and when asked to pick up their hindlimbs. Most significant changes were a wider hindlimb stance of 0.39 ± 0.15 m and increased abduction angle of 48.7 ± 7.52° and hoof elevation (0.77 ± 0.08 m left and 0.94 ± 0.11 m right) when the horses were asked to pick up their hindlimbs. Control horses could back easily in a straight line and with symmetrical hoof separation and could maintain their center of weight when picking up their hindlimbs. In contrast, the horses with Shivers had difficulty backing straight, were slower, with a shorter stride and asymmetric hoof separation. They could not maintain their center of balance when picking up their hindlimbs. The findings of this pilot study advance the understanding of the movement disorder of Shivers and could be used as outcome measures to evaluate treatment modalities.
•Shivers is a progressive movement disorder unique to horses that causes rapid hyperflexion and abduction of one or both hindlimbs with muscle trembling and elevation of the tail.•Despite the decades since it was first described, there is still no known treatment and many unanswered questions about its pathophysiology.•Three-dimensional kinematic motion analysis has been a powerful modality to characterize human and canine movement disorders but has not yet been used to evaluate Shivers.•Three-dimensional motion analysis identified multiple parameter differences between horses with Shivers and normal horses during backing and when asked to pick up their hindlimbs. The sensitivity of this modality allowed for detection of changes in the horses with Shivers at the walk and to characterize differences in the lumbar and pelvis function of these horses.•The findings of this pilot study advance the understanding of the movement disorder of Shivers and could be used as outcome measures to evaluate treatment modalities.