Cranial nerve exam Flashcards
How would you test CN-I (olfactory)?
Have you noticed any changes in smell recently?
How would you test CN-II (optic)?
- Visual acuity
- Visual fields
- Pupillary reflexes
- Fundus
How would you test visual acuity?
“Do you wear glasses or contacts?”
“Have you had any problems with your vision lately?”
Snellen chart, ask pt to read sth covering one eye at a time
How would you test visual fields?
- Inattention: look at may nose, put your arms at both sides and wiggle one or two fingers (stroke)
- Visual field (ideally with a white hat pin)
“look at my nose, can you see my whole face”
Cover one eye at a time while also covering own opposite eye. Test all four corners for both eyes
How would you test pupillary reflexes?
Ask pt to concentrate on spot on the wall
Look for direct and consensual response
Swinging torch test !
What is RAPD?
Rapid afferent pupillary defect
Often due to optic neuritis secondary to MS
investigate with swinging torch test
How would you test the fundus?
“I would ideally like to examine the funds by ophthalmoscopy”
How would you test CN-III, CN-IV and CN-VI (oculomotor, trochlear, abducens)?
- Eye movements
2. Accommodation
What would abnormal position of eye indicate?
Oculomotor lesion
How would you test eye movements?
“Keep your head still and follow my finger”
“Let me know if you see double at any point”
H movement
What is ophthalmoplegia?
Paralysis of the extraocular muscles that control the movements of the eye
Can be seen when doing eye movement test
If there is diplopia during eye movement tests, what would you ask?
- Ask if image is separated horizontally or vertically
- Cover each eye in turn, which image disappears?
- Looking to the side: lateral image from affected side
- Looking down: lower image from affected side
- Looking up: upper image from affected side
How would you test for accommodation?
‘Keep looking at my finger”
Bring finger to nose of patient, pupils should constrict
How would you categorise the tests for CN-V (trigeminal)?
- Sensory
- Motor
- Reflexes
How would you test for sensory in CN-V (trigeminal)?
Ask patient to close eyes and say yes when you touch them
Go over:
- Ophthalmic division: above eyebrows
- Maxillary division: over zygoma
- Mandibular division: jaw
Do both sides feel the same?
How would you test for motor in CN-V (trigeminal)?
- Jaw opening against resistance
2. Jaw clenching: feel masseter and feel frontalis
How would you test for reflexes in CN-V (trigeminal)?
- Mention corneal rerflex (or cotton wool in nostril)
2. Jaw jerk
What is a minimal or absent jaw jerk indicative of? And a brisk one?
Minimal: normal
Brisk: UMN, stroke, tumour, MS
How would you categorise the tests for CN-VII (facial)?
- Facial tone
- Motor
- Sensory
How would you test for facial tone in CN-VII (facial)?
Look for reduced facial tone:
- Reduced wrinkling of forehead (LMN)
- Drooping of corner of mouth
- Flattening of nasolabial fold
How would you test for motor in CN-VII (facial)?
Raise eyebrows
Screw up eyes, and don’t let me open them
Puff out cheeks
Teethy smile
How would you test for sensory in CN-VII (facial)?
“Have you noticed any changes in taste (anterior 2/3 of tongue; chordates tympani)
“Are you troubled by loud noises?” (branch to stapedius)
How would you test for CN-VIII (vestibulocochlear)?
- Hearing: stroke tragus and look at ear. Whisper numbers on both sides
- Rinne and Weber test
How would you test for CN-IX, CN-X and CN-XII (glossopharyngeal, vagus, hypoglossal)?
- Bulbar function: say aaa and look at movement of uvula, speech, water swallowing
- Tongue: appearance and movement
What does choking or spluttering of water indicate?
Possible bulbar deficit
What does a flaccid, wasted or fasciculating tongue indicate?
Bulbar palsy
What does a spastic and contracted tongue indicate?
Pseudobulbar palsy
How would you test for CN-XI (Accessory)?
Trapezius - shrug against shoulder resistance
Sternocleidomastoids - turn head against resistance
What tests would you recommend after a cranial nerve examination?
Fundoscopy
MRI/CT
Formal hearing test
What is the cause of unilateral versus bilateral ptosis?
Uni: CN III palsy, Horner’s, congenital
Bi: MG, myotonic dystrophy, congenital
What are features of CN III palsy?
Eyes deviated down and out
Ptosis
What are the causes of optic nerve palsy?
Trauma
Frontal lobe tumour
Meningitis
What are the causes of olfactory nerve palsy?
Monocular blindness: MS, giant cell arteritis
Bitemporal hemianopia; pituitary adenoma, internal carotid aneurysm
Homonymous hemianopia: anything behind chiasm, stroke/tumour/abscess
What are the causes of oculomotor nerve palsy?
Pupil spared: diabetes
Complete: PCA aneurysm, raised iCP
What are the causes of trochlear nerve palsy?
Rare! Orbit trauma
What are the causes of trigeminal nerve palsy?
Idiopathic: trigeminal neuralgia
Acoustic neuroma
Herpes zoster
What are the causes of abducens nerve palsy?
Skull fracture including petrous temporal bone
nasopharyngeal carcinoma
Raised ICP
What are the causes of facial nerve palsy?
Forehead affected (LMN): Bell’s, malignant parotid tumour, herpes zoster, sarcoid
Forehead spared (UMN): stroke/tumour
What are the causes of vestibulocochlear nerve palsy?
Excessive noise levels
Jenieke’s
Furosemide
Gentamicin
What are the causes of CN-IX/X/XII nerve palsy?
LMN: MND, diphtheria, polio, MG, GB-syndrome
UMN: MND, bilateral strokes, MS
What cranial nerves are affected in Paget’s disease of bone?
Bony impingement on nerves: V, VII, VIII
What cranial nerves are affected in cavernous sinus thrombosis?
III, IV, VI (ophthalmic pani)
