Neurological Problem Signs in Horses
by Debora Johnson
What do you look for in a horse to identify neurological problems? This is one problem area that is not always readily apparent. It is also one area that is often difficult to determine what the cause of the problem might be and if it is fixable. Let's take a closer look. I was in the process of purchasing a horse and in the pre-purchase exam the vet stopped the exam and said the horse most likely had EPM or Wobbles. It was the vet's recommendation to find another horse to purchase. That is what I did.
There are four major areas that need to be closely scrutinized for neurological problems in the horse:
- Evaluate horse's mental signs
- Evaluate the head and its parts
- Evaluate muscle coordination and spinal reflexes
- Evaluate horse's gait from ground only first
- Evaluate horse's posture
There are a number of signs to look for when evaluating mental signs for neurological problems in horses:
Evaluate the Head and Its Parts
- Compulsive circling
- Head pressing (head pressing is a condition characterized by the compulsive act of pressing the head against a wall or other object for no apparent reason. This generally indicates damage to the nervous system, which may result from a number of causes, including prosencephalon disease (in which the forebrain and thalamus parts of the brain are damaged), and some types of toxic poisoning
- Seizures or convulsions
There are a number of signs to look for when evaluating the horse's head and its parts for neurological problems in horses:
Evaluate Muscle Coordination, Tone and Spinal Reflexes
- Normal tongue movement
- Tongue is retracted not just hanging out
- Horse can chew normally
- Eye function is normal/no repetitive eye twitching (nystagmus), no abnormal pupils
- Head is held normally--not a tilt, no shaking, held in normal position
- Eye lids are normal/not drooping
- Normal ears/no drooping
- Normal nostrils/both will flare and no drooping
- Normal mouth/not drooping or drooling
- No deviation in the jaw
- No food coming out of nostrils
There are a number of signs to look for when evaluating muscle coordination, tone and spinal reflexes for neurological problems in horses:
- Tail should hang straight down and not to either side
- The anal area should have good tone and be symmetrical
- Muscle atrophy should not be present
- Check horse for abnormal sweating
I take a key and gently run the smooth back of the key down what I lovingly call the "zipper" of the horse's underbelly to see if the horse arches his back in response to the key. I also take my thumb and pointer finger and gently press down on either side of the horse's spine beginning at the withers and going all the way down to the tail to see if the horse responds. This is often referred to as "skin flinching." The horse should respond, however, not excessively in any of these nerve reflexes.
Evaluate Gait and Posture
- Evaluate standing posture - Look for muscle atrophy, sloping hips, uneven legs, uneven feet, any sagging or drooping--asymmetrical areas, balance, etc.
- Take the tail, bring the horse's nose to the tail and have the horse turn in a circle both directions. Make sure you can get out of the way if the horse falls over. A neurologically impaired horse has difficulty with this maneuver.
- Cross tie the horse. Square up the horse so he is standing straight. Stand to the side and take the horse's tail in your hand. Gently pull the horse's tail to try to pull him off his squared position. The horse should lean away from your pulling movement. Be gentle when pulling--do not jerk! Do the other side the same way. The horse should not be able to be pulled off square!
- Walk the horse straight, around curves, do serpentines, and circles.
- Back the horse. Neurologically impaired horses often are unable to back properly. They do not know where their legs are.
- Balance - look at the horse's balance.
- Involuntary movements - Look for any involuntary movements such as legs jerking upward or outward, head jerking, etc.
- Incoordination - Look for any uncoordinated movements. You will see this most readily in the placement of the horse's feet. Are any feet dragging, not being equally lifted and placed, crossed over one another without asking for side passes, etc.
I do not get on a horse until all this has been evaluated from the ground. Then I always ask the seller to get on the horse so that I am able to see the horse perform many of these listed movements in a confined area such as a ring. I have the rider have the horse perform in all its gaits whether three gaited or five-gaited. It does not matter if the horse is a "gaited" horse or not. The evaluation is the same, just with different footfalls and different conformation types.
For More Information:
Clues for Recognizing Confusing Neurologic Syndromes
The Neurological Examination - Part I
The Neurological Examination - Part II
Neurological Diseases in Horses