What can I expect a veterinary neurologist to do during a neurological exam?
Before a diagnosis can be made your pet’s neurologist will need to gather some information. The three key aspects of this exam will include:
- A detailed medical history
- A physical examination
- A comprehensive neurological examination.
The purpose of the neurological exam is to determine whether your pet has neurological disease and the most likely location (neurolocalization) of the disease within the nervous system.
It is important to note that the neurological exam only suggests the location of the disease, and does not tell us which disease is present.
Neurology is like real estate…it’s all about location, location, location. For example, if you lined up 3 dogs, one with a brain tumor, one that had a stroke and one that had a focal area of inflammation in the same area of the brain, their clinical signs would be similar, to identical.
Thus, the neurological exam tells us the location of disease and allows us to focus our diagnostic testing to a specific area of the nervous system.
A neurological examination includes 6 major components:
Your pet will be observed in the exam room while the neurologist obtains the medical history. This will provide an idea of the level of consciousness your pet is displaying. Your pet should be fully alert and interact normally with you, the doctor, and his/her environment. Altered levels of consciousness (dullness, disorientation, stupor, and coma) can indicate disease in the front part of the brain (forebrain) or in the brainstem.
It is important to note that your pet may be displaying an altered mental status as a result of being systemically ill (similar to how a person with a cold would behave), so this does not necessarily mean he or she has a neurological disease.
Gait & Posture
As part of the neurological exam, the neurologist will observe your pet’s gait and body posture. Often the doctor will have you walk your pet in the hallway or outdoors where there is good traction. While watching your pet walk, the neurologist is trying to determine whether there are any abnormalities which suggest neurological disease, such as weakness or ataxia (incoordination).
The neurologist is also looking for lameness which can be attributed to either orthopedic disease (e.g., arthritis, cruciate ligament injury) or neurological disease. By analyzing the gait, we often can narrow the location of disease to the spinal cord, brain, or peripheral nerves.
Cranial Nerve Examination
There are 12 pairs of cranial nerves which leave the brain and supply various structures of the head. Your pet’s neurologist will perform a series of tests that will examine each of these nerves individually. These nerves originate and exit from specific areas of the brain. By testing these nerves individually, we can often narrow the location of the disease to a specific area of the brain.
“Postural reaction testing” is a series of tests which analyze your pet’s conscious and unconscious recognition of the location of limbs in space. Your neurologist will most likely test this by flipping a paw upside down and seeing how quickly your pet replaces it in the normal position or hopping your pet from side to side. If any limbs show abnormalities, the location of the disease can be narrowed down. For example, an abnormal response to postural reaction testing in the right legs could indicate disease on the right side of the cervical (neck) spinal cord or brainstem, or the left side of the forebrain.
The neurologist will test your pet’s reflexes. You might be familiar with some of these as they are similar to tests for people. The patellar reflex (knee jerk reflex), for example, is the same in pets, as it is in people; the doctor strikes the patellar tendon on the knee and looks for a knee jerk. This reflex tests the femoral nerve. The neurologist will also test the withdrawal reflex in all limbs by gently pinching your pet’s toes and having them pull their foot back.
By testing these and other reflexes, the neurologist will be able to determine if there is spinal cord disease or disease of the nerve as it travels through the leg.
The last step the neurologist will likely perform is to assess your pet for areas of discomfort or pain. This is done by gently pressing on the head, neck and back to assess for muscle tensing or crying that may indicate pain. Some pets may show obvious signs of pain during the exam. For example, a dog with neck pain typically holds his head and neck low and is resistant to looking side to side. However, some types of pain can have similar signs. A dog with belly pain and a dog with back pain may look similar because they will both stand with a tense abdomen and a hunched posture.
Conversely, the lack of pain response will also provide valuable information to your neurologists. Some diseases, like strokes, are not usually painful. The presence or lack of a deep pain response (when the neurologist pinches your pet’s toes very hard to see if they feel them) is important in determining the prognosis of spinal cord injuries.