Trigeminal-mediated headshaking
Horses with trigeminal-mediated headshaking show violent, usually vertical, shaking of the head, rubbing of the muzzle and snorting, which we believe is caused by nerve pain.
Such nerve pain is very difficult to treat and does not respond to anti-inflammatories and painkillers.
Research has shown that the trigeminal nerve (the main nerve providing sensation to the face) fires at an inappropriately low threshold in headshaking horses such that harmless stimuli (e.g. rain, UV light) are perceived as painful.
The cause of this misfiring is not fully understood, but the nerve appears normal when examined under a microscope, indicating that the nerve itself is not physically damaged and therefore the nerve dysfunction is potentially reversible.
EquiPENS neuromodulation in horses
PENS therapy is used in human medicine for people who suffer from nerve-related pain. Research into the use of this treatment in horses with trigeminal-mediated headshaking has shown some encouraging results, and we are pleased to be able to offer this as a treatment option at Chine House.
The procedure involves electrical stimulation of the trigeminal nerve under sedation. The procedure is usually well-tolerated and has a low rate of complications. We usually recommend a course of at least three treatments before determining if there has been a response.
Not all horses will respond to this treatment. Current veterinary evidence shows a success rate of 38% in horses that have failed to respond to all other therapies. Treatment success in these cases is defined as at least two months’ remission, allowing a normal return to ridden work.