The Neurologic Exam and Neurolocalization

The Neurologic Exam and Neurolocalization

Jeremy Shomper MEd DVM DACVIM (Neurology/Neurosurgery)

MVMA Convention 2022

Performing a complete neurologic exam is absolutely necessary for accurate neurolocalization. When performed in a sequential and consistent order the neurologic exam is efficient and helps guide empirical therapy, diagnostic recommendations, and a succinct specialist referral (when necessary). There are 6 parts of the neurologic exam; observation, gait analysis, postural reactions, cranial nerve exam, spinal reflexes, and palpation.

Observation – When observing an animal take note of its interactions with the environment. Is this appropriate or inappropriate? Also note the patient’s overall level of consciousness and posture.

Gait analysis – Watch the patient walk both freely and on leash. The most basic question is whether or not the animal is ambulatory. You should assess the regularity or predictability of the gait. Additionally, you can incorporate obstacles and/or utilize stairs or curbs to more readily distinguish subtle abnormalities.

Postural reactions – Postural reactions evaluation the animal’s awareness of limb and body position (proprioception). There are multiple ways to evaluate an animal’s proprioception including proprioceptive placing, hopping, hemi-walking, wheelbarrowing, and visual/tactile placing just to name a few. The goal is to categorize the animal’s proprioception as normal/abnormal as well as identify the body parts that are affected.

Cranial nerve exam – The cranial nerve exam serves to identify function (or dysfunction) of the 12 cranial nerves. Some nerves are evaluated in multiple reflexes and others are much more difficult to accurately assess. Cranial nerve dysfunction helps to identify intracranial disease and also provides a more specific localization with the brain.

Spinal reflexes – Spinal reflexes allow the veterinarian to assess the integrity of a reflex arc. The goal is to categorize the reflex as reduced, normal, or exaggerated. Spinal reflexes are critical for accurate neurolocalization. There are many spinal reflexes to choose from, though patellar reflexes, withdrawals, cutaneous trunci, and perineal reflexes are essential.

Palpation – Palpating the spinal column is helpful in neurolocalization as well as developing a list of differential diagnoses. Additional attention should be paid to palpating the limbs and head in an attempt to identify potentially subtle muscle atrophy.

Generally, there are 8 clinically distinct regions of the central nervous system. They include; forebrain, brainstem, cerebellum, C1-5, C6-T2, T3-L3, L4-S3, and the peripheral nervous system. The information gathered during the neurologic exam allows a lesion to be localized to one (or multiple) of these regions.

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