Quantitative sensory testing and trigeminocervical reflex thresholds in a Warmblood gelding affected by trigeminal-mediated headshaking

Diagnosing trigeminal‐mediated headshaking (TMHS) in horses primarily depends on identifying characteristic clinical signs such as headshaking and nasal irritation, along with excluding non‐trigeminal causes through additional diagnostic techniques, primarily imaging. Aside from somatosensory evoked potentials, which require anaesthesia and are technically challenging, no tools currently assess trigeminal dysfunction, the hallmark of TMHS. We describe for the first time the application of quantitative sensory (QST) and trigeminocervical reflex (TCR) threshold testing for the evaluation of trigeminal sensory function in a 6‐year‐old Holstein gelding with TMHS. Both methods are simple to apply and feasible in an awake, unsedated state. While quantitative sensory testing indicated rather normal behavioural responses to tactile, mechanical, and thermal stimulations, the TCR thresholds, determined through electromyographic recordings from the splenius muscle following electrical stimulation of the infraorbital nerve, were considerably lower than those previously reported. If these observations are confirmed on a larger scale, TCR testing could become a promising non‐invasive, easy‐to‐apply diagnostic tool for the quantitative assessment of peripheral neural sensitisation in horses affected by TMHS, potentially useful to evaluate severity, monitor progression over time and response to treatment.