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. 2025 May;57(3):645-653.
doi: 10.1111/evj.14132. Epub 2024 Jul 17.

Use of a poll-mounted accelerometer for quantification and characterisation of equine trigeminal-mediated headshaking

Kirstie Jane Pickles  1 , David J Marlin  2 , Jane Michelle Williams  3 , Veronica L H Roberts  4
Affiliations

Use of a poll-mounted accelerometer for quantification and characterisation of equine trigeminal-mediated headshaking

Kirstie Jane Pickles et al. Equine Vet J. 2025 May.

Abstract
in English, Spanish

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.

Historial: La sacudida de cabeza (HS) en equinos mediada por el nervio trigémino (TGM), es un síndrome de dolor facial neuropático caracterizado por movimientos de cabeza de intensidad y frecuencia variables y por síntomas de irritación nasal. No existe un método preciso para cuantificar y/o caracterizar la gravedad de HS.

Objetivos: Desarrollar y validar una medida objetiva de TGMHS. DISEÑO DEL ESTUDIO: Estudio prospectivo de casos y controles. MÉTODOS: Caballos presentados para la investigación de HS fueron reclutados junto a aquellos presentados para cojera de mano (LAME) y examen de pre‐compra como controles saludables (CONTROL). Datos de los movimiento de la cabeza fueron recolectados durante cinco minutos mientras trotaban a la cuerda usando un acelerómetro tri‐axial, con un rango de ±16 g y frecuencia de muestreo de 800 Hz, ajustado a la testera de la cabezada. Las grabaciones se exportaron para ser procesadas. Detección de picos fue realizada usando umbrales mínimos y máximos de −1g y + 1g (corregidos para gravedad) y un muestreo mínimo de 10 picos de ancho.

Resultados: Cincuenta y seis caballos fueron incluidos en el estudio; 18 TGMHS, 10 no‐TGMHS, 12 LAME y 16 CONTROL. Las características y la frecuencia de los movimientos de cabeza verticales (eje Z) de caballos TGMHS, difirieron significativamente de otros caballos. Los caballos TGMHS presentaron picos con una fuerza‐g positiva con mayor promedio y máxima (P < 0.005) y una fuerza‐g negativa con menor promedio y mínima (P < 0.001), con mayor frecuencia de picos/min (P < 0.001), y un porcentaje mas de doce veces mayor de picos >+2 g en comparación a los otros caballos (P < 0.001). Las características de las curvas del operador del receptor de los picos promedio >+2 g (CI 0.72–0.95), del porcentaje de picos <−2 g (CI 0.66–0.92), y del porcentaje de picos <−2 g y > +2 g (CI 0.72–0.96) mostraron una excelente discriminación de caballos TGMHS con respecto a caballos LAME, CONTROL y no‐TGMHS.

Limitaciones principales: Población de caballos derivados, numero de muestra pequeño, y los caballos control no fueron evaluados por enfermedades ortopédicas.

Conclusiones: Los datos de acelerómetros por trote a la cuerda, dan una medida objetiva de HS y permiten diferenciar entre TGMHS, no‐TGMHS, movimientos normales de cabeza y aquellos asociados a cojera de mano. El uso de acelerómetros puede ayudar en el diagnostico de HS y monitorear las estrategias de manejo.

Keywords: accelerometer; headshaking; horse; severity; trigeminal‐mediated.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Lateral (A) and caudorostral (B) view of the position of the accelerometer fixed to the bridle headpiece. The accelerometer is shown by a red circle.
FIGURE 2
FIGURE 2
A 20‐s sample of vertical (Z axis) head movement data from a CONTROL horse, a LAME horse (2/10) and a horse with trigeminal‐mediated headshaking (TGMHS) using a poll‐mounted accelerometer during 5 min of lungeing. Headshaking episodes can be seen at around 2.5, 4.3, 12.5, 13.5 and 19.2 s of the TGMHS horse recording.
FIGURE 3
FIGURE 3
(A) Vertical (Z axis) accelerometer data variables with acceptable discrimination between trigeminal‐mediated headshaking horses (TGMHS) and CONTROL, LAME and non‐trigeminal‐mediated headshaking (NONTGMHS) horses combined. (B) Receiver operator characteristic (ROC) curve values and confidence intervals (CI) for vertical (Z axis) accelerometer data. +VE, positive; −VE, negative; NPV, negative predictive value; PPV, positive predictive value.
FIGURE 4
FIGURE 4
(A) Vertical (Z axis) accelerometer data variables with excellent discrimination between trigeminal‐mediated headshaking horses (TGMHS) and CONTROL, LAME and non‐trigeminal‐mediated headshaking (NONTGMHS) horses combined. (B) Receiver operator characteristic (ROC) curve values and confidence intervals (CI) for vertical (Z axis) accelerometer data. +VE, positive; −VE, negative; NPV, negative predictive value; PPV, positive predictive value.
See this image and copyright information in PMC

References

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