Search

Background: In horses with trigeminal‐mediated headshaking (TMHS), clinical signs are likely to be expression of neuropathic facial pain. Currently, subjective assessment of disease severity is used as measure of compromise of animal's welfare. Objectives: To develop and validate a precise scoring system for TMHS: History, Rest and Exercise Score (HRE‐S). The HRE‐S consists of three subscores: history score (H‐S), resting score (R‐S) and exercise score (E‐S). Study design: Retrospective observational study. Methods: Seven masked observers with different experience used HRE‐S to score 40 video recordings taken during rest and lungeing including five duplicates. Video recordings were taken from nine horses with TMHS and three controls. Inter‐ and intraobserver reliability and practicability of HRE‐S were assessed. For every video recording severity of clinical signs was graded by every observer using an intuitive global‐type‐scale and interobserver reliability was calculated. Convergent validity was evaluated comparing HRE‐S to groups created by an existing score (grade 0–3). Discriminant validity was analysed comparing HRE‐S to groups created by intuitive global‐type‐scale. Results: Reliability for HRE‐S was excellent, irrespective of observers experience: Spearman's Rho = 0.946, p < 0.001 (intraobserver reliability) and intraclass correlation coefficient = 0.98, p < 0.001 (interobserver reliability). Interobserver reliability for intuitive global‐type‐scale was fair to substantial: Fleiss' κappa = 0.48 (R‐S) −0.63 (E‐S). Groups created by intuitive global‐type‐scale had significantly different R‐S and E‐S (p < 0.05), demonstrating discriminant validity. Convergent validity was proven as horses with grade 3/3 had significantly higher average E‐S and total scores compared with an existing score than those with grade 0/3 or 1/3 (p < 0.001). Main limitations: Retrospective nature, video recordings, sample size. Conclusions: HRE‐S is a valid and reliable score evaluating disease severity in TMHS, independent of observers' experience. [ABSTRACT FROM AUTHOR]

The term "equine trigeminal-mediated headshaking" (TMHS) has replaced the previously used diagnosis of "idiopathic headshaking" to reflect the clinical signs, which are considered to characterise trigeminal neuropathic pain (Pickles et al., [10]). Nerve conduction studies by Aleman et al. ([3], [1]) established a 10-fold reduction in the activation threshold of the maxillary branch of the trigeminal nerve in 6 headshaking horses compared with 6 control horses. & Love, S. (2017) Trigeminal nerve root demyelination not seen in six horses diagnosed with trigeminal-mediated headshaking. [Extracted from the article]

Background: Equine trigeminal-mediated (TGM) headshaking (HS) is a neuropathic facial pain syndrome characterised by varying intensity and frequencies of head movements and signs of nasal irritation. An accurate method for quantification and/or characterisation of HS severity is lacking., Objectives: To develop and validate an objective measure of TGMHS., Study Design: Prospective case control study., Methods: Horses presenting for investigation of HS were recruited alongside those presenting for forelimb lameness (LAME) and pre-purchase examination as well as healthy controls (CONTROL). Head movement data were collected for 5 min whilst trotting on the lunge using a tri-axial accelerometer, with a range of ±16 g and sampling rate of 800 Hz, attached to the bridle headpiece. Recordings were exported for processing. Peak detection was performed using minimum and maximum thresholds of -1 g and +1 g (corrected for gravity) and a minimum peak width of 10 samples., Results: Fifty-six horses were included in the study; 18 TGMHS, 10 non-TGMHS, 12 LAME and 16 CONTROL. Characteristics and frequency of vertical (Z axis) head movements of TGMHS horses differed significantly from other horses. TGMHS horses had peaks with greater mean and maximum positive g-force (P < 0.005) and lower mean and minimum negative g-force (P < 0.001), greater frequency of peaks/min (P < 0.001) and over 12 times greater percentage of peaks >+2 g compared with other horses (P < 0.001). Receiver operator curve characteristics of percentage of peaks >+2 g (CI 0.72-0.95), percentage of peaks <-2 g (CI 0.66-0.92) and percentage of peaks <-2 g and >+2 g (CI 0.72-0.96) showed excellent discrimination of TGMHS horses from LAME, CONTROL and non-TGMHS horses., Main Limitations: Referral population of horses, small sample size and control horses were not evaluated for orthopaedic disease., Conclusions: Accelerometer data from trotting exercise on the lunge provides an objective measure of HS and can differentiate between TGMHS, non-TGMHS, normal head movements and those associated with forelimb lameness. Accelerometer use may aid HS diagnosis and monitoring of management strategies., (© 2024 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)