CASE STUDY: Head-shaking

Head-shaking, more formally known as trigeminal-mediated head-shaking, is one of the more frustrating equine afflictions. Affected horses flip their heads up and down uncontrollably.   More than minor symptoms usually mean the horse cannot work and is generally miserable.  The constant head movement stresses the neck, withers, and back and severe symptoms may interfere with eating or drinking.  Horses may stand close to or touching walls, fences, or other horses, using proximity to override what is a reflex nerve action that has gone rogue. Daylight and wind are often reported to make the behavior worse as are faster gaits such as moving from the walk to the trot.  In about 60% of horses the symptoms appear seasonally, usually beginning in the spring or summer and resolving as fall moves into winter.  Nothing works particularly well to control it.  Symptoms may improve to a limited degree with light blocking masks or keeping horses inside during daylight hours but most attempts to control it with medications are unsuccessful.  The causality is known — the trigeminal nerve in the face has an abnormally low threshold for firing. Instead of only firing when necessary, such as when a fly lands on the nose, it fires constantly to everything.

Below is 21 year old Welsh pony-TB gelding with classic head-shaking behavior (first two videos).  He has a spring onset and fall resolution with symptoms during the summer that range from moderate to severe.  He is worst on windy days.  Light-blocking masks make no difference.  Numerous approaches have been tried over the last decade with nothing working particularly well.  I know this because he lives here.  Each year a different combination of nutraceuticals has been used and each year enough improvement has been achieved that he can do the job he loves (walking trail rides).  But not on windy days. And out in the field and in the shade of the barn his head continued to bang up and down, stressing his entire body.

Head-shaking out in the field, attempting to use the proximity of other horses to suppress the reflex.
Unable to control his head even inside the shaded barn and wearing a light-blocking mask.

This spring when he started flipping his head  I did a literature search to see if anything new had been reported and found a research paper in a small number of horses that reported reductions in the behavior using specific minerals in specific forms to alter the nerve firing threshold. 

I replicated the study exactly — and it didn’t work.  There was no change in the head flipping.  But the premise made sense — and I am a scientist— so I modified the protocol (dosing, duration, and some of the mineral forms) and watched.

Slowly the head flipping decreased.  And then it stopped.  Entirely.  And it has stayed stopped.  He can walk, trot, and canter in the field or under saddle without a single abnormal head movement.  The wind no longer bothers him.  Note the absence of a mask.

On the protocol he is able to be outside, in the sun, in the breeze, without a mask and his head is finally quiet.

A simple inexpensive intervention tailored to a particular horse that works with the body resolved a 10-year health problem. 

Need help with a horse?  See here: https://4oaksequine.com.

For review of head-shaking see here https://ceh.vetmed.ucdavis.edu/health-topics/trigeminal-mediated-headshaking#:~:text=Trigeminal%2Dmediated%20headshaking%2C%20formerly%20known,violently%2C%20without%20any%20apparent%20cause.).

See here for the research article (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6524471/ ).  NOTE:  Supplementing with boron must be done with care; the safe range for this mineral is narrow in other animals and there are no toxicity studies in horses.  The protocol that worked includes two forms of magnesium and no boron.

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