Cranial Nerve Testing Lab Flashcards
What elements from pt history/ systems review would warrant a cranial nerve exam?
fatigue, malaise, fever/chills/sweats, nausea/vomiting, dizziness/lightheadedness, paresthesia/numbness, weakness, change in mentation/cognition, visual disturbances.
Trauma.
Hx of neurological condition.
What are sign/symptoms of headaches that we should not ignore?
o headache begins after lying down, awakens individual up, &/or is present upon awakening (e.g. may indicate hypertension or tumor)
o headache with documented elevated BP
o insidious or new onset of headache (60 years (temporal arteritis)
o no previous personal or family history of migraine headaches
o headache begins with, and remain as, unilateral pulsating pain in synchrony with the heartbeat
o headache associated with projectile vomiting, but no nausea
Other reasons to do a cranial nerve exam based on gait, facial changes, and cognition?
• balance, gait, gross movements, tremors • asymmetrical facial features such as: o pupils o ptosis o strabismus o facial contour • hearing loss or hypersensitivity • change in mentation • speech changes; hoarseness; throat clearing
If patient answers yes to these questions, you may consider doing a cranial nerve exam?
Yes answers to changes in any of the following: • smell • visual acuity • diplopia • taste • swallowing
How do you test CN I?
make sure nasal passages are clear. pt closes eyes. blocks one nostril and hold up a scent (like bar of soap), ask pt to identify. Occlude other nostril and identify another scent (like cinnamon etc).
How do you test CN II?
First test visual acuity with a Snellen or pocket eye chart. Then evaluate field of vision. Do this by having them identify when they can see your finger enter a visual field quadrant.
How do you test CN II and III?
ask patient to focus on object in the distance. observe pupil diameter in dimly lit room. Note symmetry between pupils. use penlight to check for direct and consensual light responses.
What is Anisocoria and what does it indicate?
one pupil is larger than another. May indicate sympathetic system disruption if pupil not allowed to dilate in dim light when light shown. May indicate parasympathetic lesion if pupil stays dilated in bright light. If the difference in size stays the same regardless of light conditions, then the issue is physiologic.
What is ptosis, and what could it indicate?
lagging of an eyelid. sympathetic nerves innervate a small muscle (Muller’s m.) that raises the eyelid, while CN III innervates the bigger levator palpebrae.
How do you test CN III, IV, and VI?
Have patient use eyes to follow pen light at different levels side to side. Note extra-ocular muscle palsies and horizontal or vertical nystagmus
How do you test CN V?
Resist jaw opening, testing masseter strength. Then test 3 regions of trigeminal nerve bilaterally with light touch and pin prick. Eye doctor may also use a puff of air on the cornea to check eye close reflex.
How do you test CN VII?
look for facial asymmetry. Then have patient make various facial expression like raising eyebrows, smiling, puff out both cheeks.
How do you test CN VIII?
Pt closes eyes and identifies which ear they can hear your fingers rubbing together. Ask them if one ear heard the noise louder than the other ear. Weber test for lateralization. Rinne test to compare air conduction to bone conduction.
How do you test CN IX and X?
Ask pt to swallow and note any difficulty. Open mouth wide stick out tongue and say “Ahh”. Observe soft palate while they do this and observe symmetry.
How do you test CN XI?
observe any wasting or weakness of trapezius muscle. Apply resistance to head rotation. Peripheral lesions produce ipsilateral sternocleidomastoid (SCM) weakness and ipsilateral trapezius weakness.Central lesions produce ipsilateral SCM weakness and contralateral trapezius weakness, because of differing sources of cerebral innervation. This is a common clinical misunderstanding
