Gait analysis is an extremely important part of the neurological exam. Too often, insufficient time is spent examining the patient’s gait and body posture. A great deal of information can be obtained before touching the patient. Neurolocalization often can be made simply by analyzing the patient’s gait and body posture.
Allow the patient to explore the exam room while obtaining the patient’s history from the owner. Dogs should be leash-walked by the owner or a staff member, and the patient should be observed walking toward and away from the observer, as well as in profile. Vary the speed of the gait and walk the patient up and down stairs. Walking the dog in circles may help identify crossing-over and ataxia. Ensure adequate traction for the patient to walk, such as concrete, grass, gym mat, or carpet. An inexpensive carpet runner or scrap piece of carpet can easily be unrolled in the hospital for gait analysis and then rolled back up again for easy storage. Alternatively, large rolls of yoga mat material can be purchased online – they are inexpensive, lightweight, easily cleaned and hung to dry, and can be rolled up and stored out of the way.
Evaluate the gait
- Paresis (weakness): dysfunction of the motor system
- Ataxia (incoordination): dysfunction of the sensory system
There are many ways to describe a patient’s gait, but most neurologists typically first describe the presence of any weakness and whether the patient is ambulatory or nonambulatory. Animals that are weak, but still able to voluntarily move the limbs, are said to be “-paretic,” while animals that are unable to voluntarily move the limbs are said to be “-plegic” (paralyzed). These suffixes are then combined with a prefix to identify which limbs are involved.
- Mono- = One limb involved (e.g., left pelvic limb monoparesis)
- Hemi- = Both limbs on same side affected (e.g., right-sided hemiparesis)
- Para- = Both pelvic limbs affected (e.g., paraplegic)
- Tetra- = All 4 limbs affected (e.g., nonambulatory tetraparesis)
- Stride length can help localize the lesion. A long-strided gait is usually a sign of an upper motor neuron (UMN) disorder, while a short-strided gait can be a sign of a lower motor neuron (LMN) spinal cord, peripheral neuromuscular, or orthopedic condition.
I’ve seen the term “nonambulatory paraplegic” used quite a bit in veterinary medicine. Technically, this is redundant since patients that are paraplegic are, by definition, unable to ambulate.
Listed below is one commonly used grading system to describe the patient’s gait. Dr. Natasha Olby and colleagues developed a separate 14-point grading system with greater detail (see Table at right) for their research studies.
0 = Paralyzed
1 = Nonambulatory with severe paresis (only slight voluntary movement) and ataxia
2 = Nonambulatory with moderate to severe paresis and ataxia
3 = Ambulatory with moderate to severe paresis and ataxia
4 = Ambulatory with mild to moderate paresis and ataxia
5 = Normal gait
Author’s opinion: Personally, I find these grading systems somewhat difficult to use on the clinic floor. They are excellent to use in studies for statistical analysis, but since there is no standard grading scale, using a grading system in clinics can lead to confusion between clinicians. I prefer to describe the patient’s gait, such as “Nonambulatory with moderate to severe parapresis (left worse than right) and proprioceptive ataxia.”
Next, describe the presence of incoordination (ataxia), a sensory phenomenon. In general, ataxia is present when the feet do not consistently land in the appropriate location while the patient is walking. There are three forms of ataxia:
- Proprioceptive ataxia (a.k.a, general proprioceptive, spinal)
- Vestibular ataxia
- Cerebellar ataxia
Each of these types of ataxia is described below. It is not uncommon to observe features of two forms of ataxia in the same patient. For example, some patients display a combination of cerebellar and vestibular ataxia due to disease affecting the vestibular components of the cerebellum (flocculus, nodulus, fastigial nucleus, caudal cerebellar peduncle).
One of the more common gait abnormalities seen in veterinary neurology is a “long-strided, floating gait.” This is a sign of an UMN lesion to the affected limbs. Many people misinterpret this floating gait as hypermetria and incorrectly localize the lesion to the cerebellum. The Pug in the video under Proprioceptive Ataxia above has a C1-C5 spinal cord lesion. Notice how the dog’s limbs seem to float in the air before contacting the ground and the elbows remain extended. While this is technically a form of hypermetria, when you hear/think about the word “hypermetria,” you would think of a cerebellar disorder. With cerebellar hypermetria, there is excessive flexion of the elbows.