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Equine Neurology - neurological disease doesn't always mean the end of a racing career

By James Tate BVMS MRCVS
First Published: 14 October 2009 - Issue Number: 14

p>Neurological problems in racehorses are not uncommon and when they do occur, they can be hugely significant. Horses suffering from neurological disease are often not diagnosed that quickly because trainers have a tendency not to consider a neurological problem unless it becomes glaringly obvious. The complaint is often vague – an unusual lameness or gait, a history of clumsiness or falling, or a blow to the head.
The neurological examination and localization of the problem
The primary aim of the veterinary neurological examination is to establish whether a neurological problem is present. It is only after this that the vet can begin to analyze all the signs in an attempt to localize the problem, for example, to the brain or spinal cord.
The physical examination begins with assessment of the horse’s general behavior and mental status before examining the nerve reflexes of the head, most of which can be easily tested with a mint. The horse hears the rustle of the mint wrapper, before smelling the mint, seeing it, taking it with its lips and tongue, using its facial muscle to chew it before finally swallowing. The next time readers feed a mint to a horse, they now know that they are actually testing many complex neurological pathways!
The vet may then proceed to examining the horse’s body – starting with the neck before moving onto the fore limbs, the back, the hind limbs and finally the tail and perineal area. Horses are then assessed at walk and trot before being asked to perform some more demanding tests, for example the ‘tail-pull’ test, turning the horse in tight circles, or asking the horse to walk whilst blindfolded.
Once the neurological examination is complete, the results are analyzed by the vet who may then be able to localize the problem. The presence or absence of different reflexes can tell the examiner a great deal about the exact location of the problem, whether it is in the brain or the spinal cord. For example, if a horse shows hind limb incoordination but its front limbs appear unaffected, then the problem lies in the spinal cord behind the withers but ahead of the tail. On the other hand, if the head reflexes are normal but the horse shows front and hind limb incoordination, then the problem must lie in the spinal cord between the head and the withers.
Wobblers
One of the most common and important neurological conditions of the racehorse is the ‘classical wobbler syndrome.’ The term ‘wobbler’ describes exactly what such horses look like – they are uncoordinated and wobbly. It is more accurately described a...

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