A head toss here and a head shake there might not make you look twice, but some owners deal with a decidedly more frustrating and potentially dangerous condition in their horses: headshaking. And what’s more, treating headshaking is a challenge in its own right, as none of the various therapeutic options have historically been considered very successful.

At the 2014 American Association of Equine Practitioners Convention, held Dec. 6-10 in Salt Lake City, Utah, Monica Aleman, MVZ, PhD, Dipl. ACVIM, shared the results of a recent study evaluating horses’ owner-reported response to headshaking treatments. Aleman is an associate professor of medicine and epidemiology at the University of California, Davis (UC Davis), School of Veterinary Medicine.

Aleman explained that idiopathic headshaking is a "spontaneously occurring disorder of mature horses causing violent head flicking, snorting, and muzzle rubbing." She said it is a distressing condition that can compromise horses’ quality of life and, in severe cases, results in euthanasia.

Although the condition’s pathophysiology remains uncertain, recent research results indicate that the trigeminal nerve (which conducts sensory information from the face, mouth, nose, sinuses, and eye) is involved, Aleman said. Headshakers appear to have a decreased threshold for nerve activation compared to normal horses, she said; this dysfunction essentially causes the horse to be hypersensitive to environmental stimuli (such as sunlight or sound) that he would otherwise ignore.

Aleman said geldings appear more likely to be headshakers than mares or stallions, and clinical signs