Neuro Exam Flashcards
The history is critically important in Neurology. Many different signs and symptoms are highly informative and provide the initial basis by which you try to localize the lesion. Your first priority is not “what is it?” but “where is it?” Are you dealing with disease of the brain, spinal cord, peripheral nerve or muscle, or perhaps, there is no disease of the nervous system at all. The patient may be experiencing “functional” signs and symptoms due to psychiatric disease, as occurs, for example, in a “conversion reaction”. You will use the results of your neurological exam to confirm or reject what you suspect to be the anatomy of the lesion
Once you have a working hypothesis for the anatomy of the lesion, the next step is to determine its pathophysiology. Here you should think in broad categories. Do the history and physical exam suggest a vascular, neoplastic, infectious, paroxysmal, metabolic, neurodegenerative or some other process.
You will learn more about each of these categories later but for now, you should realize that vascular usually means stroke characterized by a sudden loss of strength, sensation, vision, language or some other function.
Paroxysmal means something is of sudden onset but unlike stroke, there is often a gain of function. For example, involuntary jerking of the limbs during a seizure or visual aura in a migraine attack
Neoplastic is usually insidious in onset, often producing pain due to tumor invading pain sensitive structures. There is a gradual loss of function and other organ systems may be involved.
Infectious causes usually produce fever, chills, stiff neck with meningitis and may involve other organ systems.
Neurodegenerative disorders, like Alzheimer disease, are insidious in onset, progressive, often painless, usually restricted to or predominant in the nervous system. So, your H&P should elicit information with a goal to make an anatomical diagnosis first and then to determine its pathophysiology. Only afterwards do you consider a differential diagnosis. This is called the Neurologic Method, and your lab testing, imaging and early treatment are typically better focused and more likely to be on target when you use the Neurologic Method.
What are the main parts of the neurologic exam?
Mental status, cranial nerves, motor function, sensory function, reflexes and gait. When you write down or present your exam to an attending, you should follow this format regardless of the order in which the information was collected.
Neuro Exam tools
A hand held Rosenbaum card tests visual acuity.
The tuning fork is useful for testing vibration sense, and being metal and cold, it can also test for the sensation of temperature.
The tongue blade checks the gag reflex.
The cotton applicators with wooden sticks can be used in many ways, typically to test light touch and the corneal reflex, but also for testing cortical integration of sensory function such as texture, stereognosis and graphesthesia
What is Stereognosis?
Stereognosis refers to your ability to identify objects through touch, for example, the feel of cotton in your fingers versus the stick.
What is Graphesthesia?
refers to the ability to recognize numbers or letters written on the palm of your hand. This is done with the wooden part of the cotton applicator.
The measuring tape is used to measure muscle bulk around a limb when atrophy is suspected and to check for optokinetic nystagmus. What is optokinetic nystagmus or OKN?
If you ever stood in a subway station and watched cars pass by, you may or may not have noticed that your eyes involuntarily jiggle due to OKN. The presence of optokinetic nystagmus indicates that the anatomical visual pathways from the eye to visual centers in the occipital cortex of the brain are all working properly.
The mental status exam may be perceived as questioning the patient’s intelligence. That can be embarrassing to the patient and awkward for the physician, so mental status testing is often performed at the end of the neurologic exam
. It is helpful to include an explanation that the testing is routine and the patient is not being singled out. On the other hand, if the interview suggests an unreliable historian, then the mental status is tested first.
How is mental status tested?
You note the level of consciousness. A patient is considered conscious if he opens his eyes to stimulation. In your typical clinic encounter, you check orientation, you ask the patient his name, his current place and the date
With alterations in mental status due to any cause, knowing _____ is usually the first thing to go?
today’s date
How can you test attention and concentration?
by asking the patient to spell WORLD forward, then backwards. You can also test “serial sevens”, that is ask him to subtract 7 from 100, 7 from 93, 7 from 86 and so on
How should immediate recall and short-term memory be tested?
Ask the patient to repeat and then remember 3 objects for the next 5 minutes, while you distract him with other cognitive tasks. Patients with early Alzheimer disease often have difficulty laying down new memories and will forget 1, 2 or all 3 of the items. They will also have problems remembering what they had for breakfast or what they heard on the news recently.
T or F. Long term memory is generally better preserved than recent memory.
T. To test, ask about the make and model of the first car bought or what color suit the patient wore at his wedding. Alzheimer patients with mild to moderate dementia will reminisce about the past with remarkable detail
Disorders of language, so-called aphasias, will affect speech but they must be distinguished from ______ in which the mechanics of speech are affected to produce slurring of words.
dysarthria
How should language be tested?
. Language is tested for fluency, comprehension, naming, reading and writing. You should ask how far the patient got in school and check general knowledge by asking him to name the Presidents starting with the current President and going backwards. Ask him to name the state capital, governor and mayor.
Check abstraction by asking him to interpret a proverb such as “people who live in glass houses shouldn’t throw stones” or “don’t cry over spilt milk” which is very simple. Ask him how a banana and orange are alike. They are fruit but a cognitively impaired patient typically will point out the differences instead.
Inquire about judgment by asking what he would do if he saw smoke in a crowded theater or found a stamped envelope on the pavement. Does the patient show insight into his own illness by asking appropriate questions or is he there to see the doctor because he got an appointment letter for reasons he does not know. Note if the patient appears depressed, unusually giddy or avoids eye contact because of sociopathic tendencies
A lesion in Broca’s area of the brain produces an expressive or Broca’s aphasia (they mean the same thing). What does this mean?
The patient has difficulty with word finding and getting words out, even though he knows exactly what he wants to say. He follows commands readily but is visibly frustrated that he can’t express his thoughts.
How would a A lesion in Wernicke’s area present?
In a receptive or Wernicke’s aphasia (they mean the same thing). The patient speaks fluently and easily but has no insight that his words and sentences are devoid of meaning. He does not comprehend and cannot follow commands, whether spoken or written, but remarkably does not seem to be bothered by this lack of comprehension and inability to communicate.
How would a lesion in the arcuate fasciculus that links the two language areas present?
results in a conductive aphasia. The patient can comprehend and speak fluently but has difficulty with repetition, especially with long sentences. Most aphasias can be characterized by asking the patient to name objects, to read, write and repeat sentences.
How can dysarthria and aphasia be contrasted?
While speech in dysarthria may be hard to understand and suggest an aphasia, the dysarthric patient communicates normally through writing. A patient with aphasia, in contrast, will show the same abnormality in writing as in speaking.
How do you test the sense of smell?
On the wards or in the clinic, go to the kitchenette and find some coffee, tea, lemon, soap or other odiferous substance.
Inspect the nares for obstruction or other pathology. Then use your cotton applicator to whisk some liquid soap, tea, coffee, whatever, and bring it to one nostril while the other is occluded by your finger. With eyes closed, ask the patient to identify the smell. Test the other nostril and ask if the smell differs on one side or the other. From a practical standpoint, smell is seldom tested unless the patient complains about its loss or experiences unusual smells.
In testing smell, You want to avoid smelling salts, ammonia and alcohol that are irritating and activate nociceptive receptors in the nares. Why?
These are mediated by the trigeminal nerve as that would be testing a different cranial nerve.
When is smell commonly lost?
In head trauma because the fine nerve fibers from bipolar cells in the nasal mucosa are sheared as they pass through the cribiform plate of the skull and never reach the olfactory bulb.
NOTE: Unusual smells, like rotten eggs or decaying meat, sometimes precede a temporal lobe seizure and constitute a seizure aura.
Olfactory information is sent along the olfactory tract to the uncus and entorhinal cortex in the temporal lobe where tumor or stroke or inflammation can distort processing of that information and produce unusual smells. You don’t have to worry about the limen insulae
When compared to olfaction, vision is a far more important function. The eye and optic nerve, cranial nerve II, should be tested routinely. For the neuro-exam, fundoscopy allows direct inspection of the retina and optic disc. Visual acuity, color vision, visual fields and pupillary function are also tested.
You should become proficient with an ophthalmoscope. A few general principles include use of a dim lit room, not being afraid to get too close to the patient, being comfortably positioned, and reminding the patient not to move her eyes but keep looking at a distant object.
You should examine the optic disc to check that the edge is sharp and not swollen. This is where the optic nerve enters the eyeball along with retinal vessels. A swollen disc may be due to raised intracranial pressure from a brain tumor or other disease and is called papilledema.
Within the disc is a “cup”. Its size and depth should be checked since a small cup can strangle the vessels passing through and cause blindness in so-called anterior ischemic optic neuropathy. A deep cup should suggest elevated intra-ocular pressure due to glaucoma.
You should examine the blood vessels and any abnormalities of the retina. Some of the more common ones are small hemorrhages and exudates that accompany diabetes, severe hypertension and other diseases.
What does retinal venous pulsations upon fundoscopy suggest?
it means that the CSF pressure at that moment in time is normal. That excludes a large number of dangerous headaches that have raised intracranial pressure like brain tumor, abscess or brain hemorrhage.
Visual acuity can be tested with a hallway Snellen chart or a handheld Rosenbaum card. Make sure that conditions are optimal for vision, including use of glasses and adequate lighting. One eye is tested at a time. Read rows from top down and note where the first error is made. Visual acuity can be affected for many reasons, most commonly, by refractive error which you can correct with glasses or use of a so-called pin hole card.
Note that you rely on the central and most sensitive part of the retina, the macula, which contains the fovea, for visual fixation, tracking moving targets and reading fine print.
How shoud be confrontation testing be done?
For confrontation testing of visual fields, the examiner and patient should be facing each other more or less at the same eye level. The patient is asked to speak up as soon as she sees the white tip of a cotton applicator moving from her outer visual periphery toward her nose. All 4 quadrants of vision are tested. When an area of the visual field seems compromised, a stronger stimulus with wiggling fingers or finger counting is attempted. Test one eye at a time.
How does vision transmission occur?
- The contralateral visual field projects onto the temporal or lateral portion of the retina. The ipsilateral visual field projects onto the nasal or medial portion of the retina
- The optic nerve carries all info from the ipsilateral eye to the optic chiasm
- Retinal fibers cross in the optic chiasm and combine with non-crossing fibers from the other eye to form a right and left optic tract
- The optic fibers synapse in each lateral geniculate nuclei. The lateral geniculate then projects axons to the primary visual cortex in the occipital lobe
What would lesion of the optic nerve cause?
A lesion of the optic nerve would produce complete monocular visual loss with normal vision in the contralateral eye
This happens with inflammation of the optic nerve in multiple sclerosis and with obstructed blood flow or ischemia to the anterior optic nerve.
How would a lesion compressing the optic chiasm present?
It would destroy crossing optic nerve fibers and causes a bitemporal visual field deficit as shown below called a bipolar hemianopia
This occurs with enlarging pituitary tumors and giant internal carotid aneurysms that compress the chiasm
What is this type of lesion called? Causes?
Loss of the contralateral visual hemifield that is identical in each eye, a so-called homonymous hemianopsia
Cause: lesion or pressure on the right optic tract; lesion of the right occipital lobe
What is this lesion called and what causes it?
right nasal hemianopia due to lesion involving the right perichiasmal area
___ desaturates before other colors with injury to the optic nerve.
Red.
Some people (10-15% males) are born color blind. Ishihara plates embed numbers among small colored dots and can be used to test color vision
A variety of neurologic disorders affect the pupils to make them smaller or larger and/or unreactive to light stimulation. .What are some common etiologies of a constricted pupil?
include glaucoma drops, opioid medication, and less commonly pontine hemorrhage that disrupts the central sympathetic tracts
When the pupil is enlarged this may indicate what?
oculomotor nerve compression by a so-called PCOM aneurysm or by early temporal lobe herniation due to a catastrophic expanding mass lesion. It might also reflect rubbing one’s eye after applying a scopalamine patch behind the ear in someone with nausea and vomiting.
Ptosis or drooping of the upper eyelid with a small pupil suggests what?
Horner’s syndrome The sympathetic tract can be damaged either by a central or by a peripheral lesion.
What is Miosis?
Miosis refers to a pupil that is small, typically 2 mm or smaller.
Mydriasis refers to an enlarged pupil, typically 5 mm or larger.
•Pupil size varies with ambient light, but averages 3-4 mm
Visual information in the retina is transmitted by neurons called what?
retinal ganglion cells
Where do retinal ganglion cell axons go?
About 85% of the retinal ganglion cell axons project via the optic nerve to the lateral geniculate body. Another 15% or so project to the midbrain superior colliculli and these fibers mediate the pupillary light reflex.
Note that light entering one eye reaches the superior colliculli on both sides and the superior colliculli in turn project to both Edinger-Westphal nuclei. What happens then?
The Edinger-Westphal nuclei project to the ciliary ganglia near the eye, which send cholinergic fibers to constrict the pupil. Thus shining a light in one eye activates both Edinger-Westphal nuclei and both pupils constrict equally and consensually.
What is the most informative bedside test in an unresponsive or comatose patient? Why?
The pupillary light reflex. It checks the integrity of the midbrain in the region where the reticular activating system is found. The reticular activating system is responsible for maintaining consciousness.
To assess the pupillary light reflex properly, you should dim the light and ask the patient to stare on one spot in the distance. You shine the light obliquely so you don’t obstruct your view of the constricting pupil. Look for identical responses in both pupils.
Note that there is an afferent, that is a receiving part, of the light reflex that is mediated by the optic nerve (CN II) and an efferent, that is the effector part, that is mediated by the oculomotor nerve (CN III).
How is accommodation tested?
The pupils normally constrict as a reflex action when fixating vision from a distant object to a near object. To check accomodation, ask the patient to look at your finger as it approaches his nose. The pupils should constrict.
Cranial nerves III, IV and VI are responsible for the movement of the eyes called extraocular movement or EOM.
Check to see that the eyes remain conjugate, that is, aligned with each other, that they move smoothly and not in little jerks (saccades) and that the patient does not experience double vision, as might occur with a weakened eye muscle due to nerve injury. Check for nystagmus, that is, a rhythmic jiggling of the eyes during movement. This is very prominent in someone with vertigo due to inner ear disease.
Check to see if the patient can look from extreme lateral gaze to the center midline in a single smooth movement versus incoordinated zigzag-like movement due to cerebellar disease.
How shoudl CN V be tested?
These are tested for sensation with a pin prick (pain sensation), a cold tuning fork (temperature) and a cotton applicator (touch). One tests all three divisions of the trigeminal nerve.
One uses cotton, including the cotton applicator, to lightly stroke the cornea and see if the patient blinks. Contact lenses may depress corneal sensation in which case the nasal hairs in the nares can be lightly stroked with a cotton wisp, a so-called nasal tickle to check for very sensitive light touch sensation.
The trigeminal nerve also innervates the muscles of mastication, the chewing, grinding muscles. These are best checked by asking the patient to open the jaw against resistance. If the pterygoid muscles on one side are weak, the jaw will deviate toward the side of weakness.
How should CN VII be tested?
To test the muscles of facial expression, ask the patient to furrow the brow, close the eyes against your efforts to open them, grit his teeth and puff out the cheeks. Look for any evidence of weakness, left versus right, upper face versus lower face, and generalized weakness from systemic disorders causing motor paralysis, for instance, botulism.
A further nuance on central lesions producing weakness of the contralateral lower face: If the lesion lies in the cortical motor areas and the deeper limbic structures are preserved, you will see the weakness when the patient is asked to make a grimace but it will disappear when the patient smiles.
If the deeper structures are affected by the lesion, the weakness will persist with the smile
You will learn later about the limbic system which mediates emotion and is important in memory and that it lies in the deeper parts of the cerebral hemisphere. The important thing to know now is that a central facial paresis may appear and disappear depending on where in the CNS the lesion lies.
This is a summary slide of what to look for on your motor exam for lesions that are “upper motor neuron” or UMN and “lower motor neuron” or LMN.
What is a lower motor neuron lesion?
refer to disease of the peripheral nerve and its cell of origin, namely the anterior horn cell or neuron that gives rise to the motor axon.
You should also check muscle strength by their innervated root levels. Typically more than one root will innervate a muscle but for purposes of localization it is useful to be aware of the one root most closely associated with that muscle.
Thus abducting the shoulders using the deltoids tests cervical root 5.
Flexing the elbow with the biceps is principally a C6 function and extending the elbow with the triceps is principally C7.
Handgrip is C8 and spreading the fingers apart, then bringing them together again, back and forth, is T1.
Shoulder abduction is mediated principally by C5 and the axillary nerve.
Flexing the arm at the elbow is mediated mostly by C6 and the musculocutaneous nerve.
Extending the arm at the elbow is principally mediated by C7 and the radial nerve.
Handgrip is mediated by C8 and involves both the median and ulnar nerves.
Moving the hand intrinsic muscles involves mostly T1 and the ulnar nerve.
Muscles controlling the anal sphincter and rectal tone are innervated by S3, S4, and S5. When a patient presents with ascending paralysis of the legs, this may be due to Guillain Barre syndrome affecting the peripheral nervous system or due to a spinal cord lesion. With spinal cord lesions, anal sphincter tone is lost while with peripheral nerve lesions, as in Guillain Barre, it is typically spared even though paralysis may be severe.
What happens when the midline portion of the cerebellum is affected?
the so-called vermis, commonly with alcoholism and also occasionally with stroke, the patient develops an ataxic or drunken gait. Mild versions of cerebellar ataxia are very common and tested by asking the patient to walk a straight line toe-heel tandem
Shown here are the sensory dermatomes.
Note C2 innervates the angle of the jaw. As mentioned earlier it should remain unaffected with damage to the trigeminal nerve causing facial sensory loss. Then note that C4 borders T2 anteriorly because a skip area is devoted to the arms. That is important to recognize when you are conducting a search for a spinal sensory level in this region with pin prick testing because you suspect spinal cord injury.
T4 is the nipple line. T10 is the belly button. L1 is the groin. L4 is the knee.
Many physicians place a vibrating tuning fork on a finger or toe, ask the patient if they feel it, and if they do, they are done. The proper way to test vibration sense is by placing the tuning fork on the interphalangeal joint just below the finger tip or the big toe. Put your finger underneath the joint and you should be able to feel the vibration through the joint. Ask the patient when he no longer feels the vibration and hopefully you will lose the vibration at about the same time, assuming you have normal vibration sense. Patients with early neuropathy still have vibration sense and will feel it but they will stop feeling the vibration before you do when testing is done correctly, typically with a latency of a few seconds
To test position sense, steady the distal interphalangeal joint with your left hand and use your right to move the toe up and down. Hold the toe by the sides so that pressure applied is equal whether movement is up or down. If you grab the toe by the nailbed with one finger and the other side with your other finger, there will be pressure applied that is uneven and that pathway will be recruited to determine up and down movement rather than proprioception when the latter is damaged.
How would a pt with midline cerebellar lesions present on a Romberg tes?
They will show a drunken walk and will usually not be able to stand with their feet together. In that case, bring the feet apart just enough for them to stand without falling and eyes open. Then ask the patients to close their eyes. If they sway and almost fall, it indicates additional dysfunction of proprioception in the legs. As in the picture, be prepared to catch the patient if he suddenly starts to sway and fall.
How is Graphesthesia tested?
By using a wooden cotton applicator to write numbers or letters on the palm of a patient’s hand and ask him to identify what is written without looking at it. The numbers should be written upright, not sideways, and the number of correct answers should be compared side to side. Like sterognosis, this also tests cortical sensory processing.
How is Jendrassik maneuver done?
The patient is asked to clasp his hands and then pull them tightly apart. This action somehow increases the amount of inhibitory signal to the spinal cord reflex and causes the reflex to increase in size. It is similar to how a tense person might startle more if suddenly touched versus the same touch when that individual is calm. You can ask the patient to press the knees together and then check the reflexes in the upper limbs, again with the idea of exaggerating the muscle stretch reflex.
What is a Babinski test?
The Babinski test is pathologic for upper motor neuron disease when it elicits an extensor plantar response.
The sole of the foot is stroked by the wooden end of that cotton applicator or another object that is somewhat sharp but not enough to injure the skin. Keys were once extensively used for this but that stopped due to concerns for transmitting HIV and Hepatitis C virus by inadvertent scraping that drew blood. Classically the little toes flare and the big one goes up. The Babinski test is typically positive in instances of stroke, head trauma, spinal cord injury and anything that injures the CNS in a major way.
