Use of a poll-mounted accelerometer for quantification and characterisation of equine trigeminal-mediated headshaking.
Authors: Pickles Kirstie Jane, Marlin David J, Williams Jane Michelle, Roberts Veronica L H
Journal: Equine veterinary journal
Summary
# Editorial Summary: Poll-Mounted Accelerometry for Trigeminal-Mediated Headshaking Trigeminal-mediated headshaking (TGMHS) remains diagnostically challenging because current clinical assessment relies on subjective observation of neuropathic facial pain signs. Pickles and colleagues developed and validated an objective measurement tool using a tri-axial accelerometer mounted on the bridle headpiece, collecting vertical head movement data during five minutes of trotting on the lunge in 56 horses across four groups: confirmed TGMHS cases (n=18), horses with headshaking of non-trigeminal origin (n=10), forelimb-lame controls (n=12) and healthy controls (n=16). TGMHS horses demonstrated distinctly different acceleration profiles, exhibiting peaks with significantly greater positive g-force (mean and maximum), lower negative g-force (mean and minimum), higher peak frequency per minute, and—most notably—over 12 times more peaks exceeding +2g compared with all other groups; receiver operator curve analysis showed excellent discrimination capacity (confidence intervals 0.66–0.96) for the percentage of peaks beyond ±2g thresholds. For practitioners involved in diagnosis and case management, this technology offers tangible advantages: an objective baseline for initial assessment, a standardised method to track response to therapeutic interventions (anti-inflammatories, local anaesthetic nerve blocks, dietary modifications), and—critically—differentiation between TGMHS and lameness-associated head movement patterns that might otherwise confound clinical interpretation.
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Practical Takeaways
- •A simple accelerometer mounted on the bridle during lunge work provides objective quantification of headshaking severity, helping differentiate true TGMHS from other causes of head movement abnormalities
- •This non-invasive technology could improve diagnosis accuracy and allow objective monitoring of whether management strategies (dietary modifications, exercise changes) are reducing headshaking severity
- •The method distinguishes TGMHS from lameness-related head movement compensations, potentially avoiding misdiagnosis and inappropriate treatment of lame horses
Key Findings
- •TGMHS horses exhibited significantly greater mean and maximum positive g-force peaks (P<0.005) and lower mean and minimum negative g-force (P<0.001) compared to control horses
- •TGMHS horses had over 12 times greater percentage of peaks >+2g compared to other groups (P<0.001) and significantly higher frequency of peaks per minute (P<0.001)
- •Receiver operator curve analysis showed excellent discrimination of TGMHS from non-TGMHS, lameness, and control horses using peak magnitude parameters (AUC 0.72-0.96)
- •Poll-mounted tri-axial accelerometer data during trotting on the lunge provides an objective, non-invasive diagnostic measure for trigeminal-mediated headshaking