Fred Wininger, VMD, MS, DACVIM (Neurology), explains how gait analysis aids in neurolocalization
The neurologic exam and neurology in general can be an intimidating subject for some. “Neurophobia is a real thing because the things that make [neurology] sexy and cool are also the things that make it scary,” said Fred Wininger, VMD, MS, DACVIM (Neurology). That is why Wininger aimed to demystify the neurologic exam during his sessions at the 2022 Fetch dvm360® Conference in Kansas City, Missouri.1
Wininger began by stating that the ultimate goal of the neurologic exam is neurolocalization. By analyzing a patient’s gait, reflexes, and responses, the clinician is able to ascribe the problem to a specific part of the anatomy and thereby run down a list of differential diagnoses. In short, once you know where the problem is, you can begin to narrow down exactly what the problem is. Wininger said, “…if you know where the problem is, and you get some general data about signalment, onset, progression, and the presence of pain, then you just open a book and I promise you the answer will be there.”
According to Wininger, the neurologic exam consists of analyzing the animal’s gait, proprioception, spinal reflexes, pain sensation, and performing spinal palpation. This article will focus on gait analysis and its implications for neurolocalization.
“I learn more from watching a dog walk than I do from doing anything else,” said Wininger. “In fact, I’ve had to modify my exam to make it more interactive because the technical staff thought that I wasn’t doing a thorough physical examination, because I knew what was wrong with the dog before I even touched it.” Here are 6 gait abnormalities and what they may reveal about where the problem lies.
Ataxia is a lack of coordination that can result in swaying, a wobbly gait, head tilt, and other possible clinical signs. Wininger said a number of different anatomic lesions can cause these issues, but are most commonly of the cerebellum, vestibular system, and spinal cord sensory pathways. Often spinal/proprioceptive ataxia is coupled with paresis (weakness) whereas cerebellar or vestibular ataxia does not.
Dysmetria is impaired flexion whereas hypermetria is hyperflexion. These patients are often described as “goose-stepping” or “prancing like a pony”. This would imply a lesion of the cerebellum
Spasticity is a state of abnormally increased muscle tone and/or stiffness for a “loss of inhibition” by the brain. These patients are often thought of as overreaching with an increase length of stride. Wininger said the limbs are overly straight and that it is typically associated with upper motor neuron lesions.
Stiffness implies muscle rigidity and can emanate from many sources. If the limb is not easily bent there is tetany, as often seen in dogs that contract tetanus. Stiffness can also be from spasticity or pain causing a reluctance to bend the joints.
Paresis is muscular weakness, often characterized by a short stride, and inability to maintain posture or joint extension. Wininger said: “Paresis is a motor dysfunction that can make it difficult to generate gait. Paresis can be caused by both upper and lower motor neuron disease, essentially anything that blocks messaging between the brain and the muscles of the limb.
Lameness is the inability or reluctance to bear weight on a limb. Wininger said this can be the result of pain from musculoskeletal disease or due to nervous system dysfunction. He noted this problem can occur in a single thoracic limb due to spinal compressive disorders, such as invertebral disk extrusion.
Wininger, F. Neurophobia—it's real! Bringing the neurologic examination out of the darkness. Presented at Fetch dvm360® Conference; Kansas City, Missouri. August 26-28, 2022.