Kinematic discrimination of ataxia in horses is facilitated by blindfolding.
Authors: Olsen E, FouchÉ N, Jordan H, Pfau T, Piercy R J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Kinematic discrimination of ataxia in horses is facilitated by blindfolding Clinical assessment of equine ataxia remains problematic because experienced neurologists show poor inter-rater agreement, particularly when signs are subtle. Olsen and colleagues used a 12-camera motion capture system (240 Hz sampling) to quantify gait variability in 21 horses, measuring marker displacement across the head, fetlock, hoof, lumbar spine and pelvis during treadmill walks under both normal and blindfolded conditions; neurological grading was performed independently by multiple raters. For horses with median ataxia grades of 2 or above, coefficient of variation in the vertical displacement of the hoof markers on the thoracic limbs provided the most reliable discrimination (area under the ROC curve 0.81, 64% sensitivity, 90% specificity), but blindfolding substantially improved diagnostic accuracy to 0.89 AUC with 82% sensitivity and 90% specificity. Blindfolding exacerbated kinematic variability in ataxic horses whilst leaving non-ataxic horses relatively unaffected, suggesting that removing visual compensation reveals neurological deficits more clearly. Whilst the authors acknowledge that collecting only three to four consecutive strides per horse may limit clinical utility, motion capture combined with blindfolding offers objective, quantifiable parameters that could standardise ataxia assessment and complement subjective clinical grading in practice.
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Practical Takeaways
- •Motion capture gait analysis provides objective measurement of ataxia when subjective clinical assessment is unreliable, particularly for mild cases
- •Blindfolding during neurological examination exacerbates movement variability in ataxic horses, making clinical signs more apparent and improving diagnostic discrimination
- •Distal limb kinematics (particularly hoof displacement) are more sensitive indicators of ataxia than proximal markers when assessed with motion capture
Key Findings
- •Coefficient of variation in maximum vertical displacement of pelvic and thoracic distal limbs provided good diagnostic yield for ataxia grade ≥2
- •Thoracic hoof marker achieved AUC of 0.81 with 64% sensitivity and 90% specificity in normal conditions
- •Blindfolding increased diagnostic accuracy with hoof marker AUC improving to 0.89 with 82% sensitivity and 90% specificity
- •Motion capture can objectively assess ataxia severity when clinical agreement among experienced assessors is poor