In addition to subjective evidence of disease (ie. symptoms which the patient reports), the neurologist will conduct a thorough neurologic examination to measure objective evidence suggestive of MS to help make a diagnosis. Objective signs of MS may be as subtle as abnormal eye movements or pupil response, spasticity or weakness in the limbs, sensory disturbances, and abnormal reflex responses.
What does a neurologic exam include?
A typical neurologic exam will assess:
- Cranial nerve function
- Coordination and strength
- Nerve sensation
- Presence of Lhermitte’s sign
Cranial nerve function
As part of the neurologic exam, the doctor will check the function of cranial nerves that control senses, such as sight, taste, and hearing, and motor movement, including the movement of your eyes and the muscles involved in speech.
As part of assessment of the cranial nerves, the neurologist will use an ophthalmoscope, a tool to visualize the back of the eye and optic nerve, to look for signs of damage to the optic nerve. The neurologist will also check for vision problems that may occur with MS, such as impaired color vision, double vision (diplopia), blurred vision, or abnormal pupil responses.
12 Cranial Nerves and Their Functions
|Cranial nerve||Type of function||Function|
|5||Trigeminal||Sensory and motor||
|7||Facial||Sensory and motor||
|8||Acoustic or Vestibulocochlear||Mostly sensory||
|9||Glossopharyngeal||Sensory and motor||
|10||Vagus||Sensory and motor||
|Adapted from Overview of neuro-ophthalmologic and cranial nerve disorders. Merck Manual for Healthcare Professionals.|
How does the neurologist check coordination and strength?
To check muscle strength, your doctor will ask you to resist pressure applied to your arms, legs, and feet. To check coordination, you will be asked to perform certain movements with your legs, arms, and hands:
- Walk in a straight line for a short distance to evaluate speed, stability, and gait
- Walk barefoot on your heels and then on your toes
- Walk with a tandem gait (place the heel of one foot against the toe of the other as you walk forward)
- Perform the heel-knee-shin test (glide the heel of one foot from ankle to shin of the opposite leg and back again)
- Perform the finger-to-nose test (touch a finger to your nose then to your doctor’s outstretched finger and back to your nose again, repeat motion many times quickly, both with your eyes open and then with eyes closed)
How does the neurologist check sensation?
You may be able to report some sensory symptoms, such as numbness, tingling, or pain, to your neurologist. Other sensory changes may be assessed during the neurologic exam.
Positional sense (proprioception) can be checked as you close your eyes and report where different parts of your body, such as your fingers and toes, are located in space or in which direction your doctor may have repositioned them.
Vibration sensitivity is checked as your neurologist touches different locations on your body, such as your toes and ankles, with a vibrating tuning fork. You will be asked to report when you can no longer feel the vibration.
To check sensitivity of touch, your neurologist will ask you to identify sharp or dull objects as they are applied to various places on your body while your eyes are closed. Another common test is the skin prick test during which the doctor uses a sterile safety pen to test skin sensitivity by poking or pricking your feet, legs, hands, arms, and torso.
How does the neurologist check reflexes?
Reflexes are involuntary and instantaneous movements of parts of your body in response to stimuli. The neurologist may use a soft hammer to check for brisk, weak, or absent reflexes in the knees, ankles, elbows, and other joints.
Unequal reflexes on either side of the body are indicative of impaired nerve function. Abnormal or absent reflexes are common in MS, especially in the abdominal area.
A common sign in MS is the Babinski reflex which indicates damage to major nerve pathways. To test for this abnormal reflex, the doctor uses a blunt, pointed implement to scrape along the sole of the foot on the outer edge, going from the heel to little toe. A normal reflex causes the toes to respond by pointing down or staying still. However, an abnormal response (the Babinski reflex) is revealed as the big toe points up and/or the other toes splay outward. The Babinski reflex is common in infants under the age of two whose neurological system has not yet fully developed.
What is Lhermitte’s sign?
If you experience an electrical sensation (buzzing or tingling) which travels down your spine or into any of your limbs when you bend (flex) your head forward, then you have a positive Lhermitte’s sign, which is a common abnormal neurologic phenomenon seen in people with MS. Lhermitte’s sign can indicate damage to the CNS, such as lesions in the cervical spine, and is useful in confirming a diagnosis of MS or monitoring disease activity.