Neuro Flashcards
What can be seen in a general inspection of the patient in a cranial nerve exam? (4)
- General appearance
- Eye position (normal alignment/strabismus)
- Ptosis (unilateral/bilateral)
- Speech/voice abnormality (dysarthia)
How is the olfactory nerve (CNI) tested?
Change in smell?
What is tested to test the optic nerve (CNII) ?
- Pupils inspected
- Visual acuity + colour vision
- Pupillary reflexes
- Visual fields
- Fundoscopy
What is inspected for in the pupils? (3)
- Size
- Shape
- Symmetry
Common pupil signs and conditions associated? (2)
- Unilateral large and fixed pupil : CNIII palsy
- Unilateral small and reactive: Horner’s syndrome
Neuro causes of decreased visual acuity (2)
- Optic nerve II pathology - optic neuritis
- Visual pathway lesion
Difference between decreased visual acuity caused by papilloedema vs optic neuritis?
Papilloedema due to raised ICP doesn’t effect visual acuity until much later
What pupillary reflexes are tested? (4)
- Direct pupillary reflex
- Consensual pupillary reflex
- Accomodation reflex
- Swinging light reflex
What are the normal pupillary reflexes?
- Both pupils (direct and consensual) CONSTRICT in response to light
How would an afferent pupil defect present? (CNII issue)
Light shone in effected nerve eye = no constriction in effected/contralateral
Light shone in contralateral pupil = constriction in both eyes
How would an efferent pupil defect present? (CNIII issue) (2)
- One dilated pupil not responding to light in either eye (no direct/consensual reflex) = also points up and out
- Other uneffected pupil will constrict (consensual reflex) when light shone in affected eye
What could an afferent pupil defect be caused by?
- Optic nerve defect
- Edinger-Westphal nucleus defect
How is the swinging light test performed?
Move the pen torch rapidly between the two pupils, shining the light for three seconds in each eye.
How can the swinging light test detect an afferent pupillary defect?
Dilation of the pupil when it should normally constrict
How is the accommodation reflex tested? (3)
- Ask the patient to focus on a distant object
- Place your finger/object approximately 15cm in front of the eyes.
- Ask the patient to switch from looking at the distant object to the nearby finger/object
What is normal accommodation reflex?
Convergence and constriction bilaterally
What is a Marcus-Gunn pupil?
Ill sustained contraction of pupil in swinging light test
What is a Marcus-Gunn pupil caused by?
Optic neuritis
What does the accommodation reflex test?
CNIII/efferent pathway
What charts are used to test colour vision?
Ishihara charts
How are visual fields assessed? (8)
- Keep glasses on
- Eye level
- Focus on nose and not finger
- Ask patient to cover their left eye with left hand
- Cover your right eye with right hand (mirrors patient)
- Position your fingertip at each border of your visual field then wiggle slowly inwards to the centre
- Do for each quadrant
- Only move tip of finger
Rare neuro cause of loss of red reflex?
Neuroblastoma
How are nerves occulomotor (III) trochlear (IV) abducens (VI) assessed? (2)
- Note ptosis
- Drawing a H
- Checking for nystagmus
Causes of ptosis (4)
- CN III pathology
- Horner’s syndrome
- Congenital/age
- Neuromuscular pathology - myasthenia
How are eye movements tested?
- Ask patient to fix on eye
- Ask patient to report any double vision
- Slowly draw Hs in front of each eye
- Pause at each point to detect nystagmus
What is nystagmus?
Flickering involuntary eye movements
What is detected in testing eye movements? (2)
- Nystagmus
- Restriction
All eye muscles are innervated by the oculomotor nerve except which ones? What are their movements and what nerve innervates them instead?
SO4LR6
- Superior oblique: downwards and in
- Lateral rectus: lateral movement
How is the trigeminal nerve tested? (2)
- Light touch and pinprick sensation (sternum first for reference)
- Feel bulk of masseter and temporalis
- Jaw clench
- Reflexes (jaw jerk)
Branches of the trigeminal nerve and their areas of sensation? (3)
Forehead - ophthalmic branch (CNVi)
Cheeks - maxillary branch (CNVii)
Jaw - mandibular branch (CNViii)
What muscles are felt for bulk to test CN V and where are they? (2)
- Masseter (jaw)
- Temporalis (temples)
How is the jaw jerk reflex tested?
- Ask patient to open mouth loosely
- Place finger horizontally across the chin
- Tap finger with a tendon hammer
Normal jaw jerk reflex
Slight closure of the jaw
Abnormal jaw jerk reflex and suggested pathology
Brisk complete closure of the jaw - upper motor CNV lesion
How is the facial nerve tested? (VII) (4)
- Inspection
- Facial movements
- Inspection of external auditory meatus
- Hearing/taste changes?
What is inspected when testing the facial nerve? (3)
- Forehead wrinkles
- Nasolabial folds
- Angles of the mouth
What are the facial movements for testing the facial nerve? And what is assessed? (5)
- Raise eyebrows : symmetry
- Close eyes: power
- Blow out cheeks: power
- Smiling: symmetry
- Close lips: power - each side
Why is the external auditory meatus inspected in testing the facial nerve?
Herpes zoster lesions – Ramsay Hunt syndrome
Shingles causing lower motor lesion in CNV
Why are hearing changes relevant in testing the facial nerve?
CNV supplies stapedius - paralysis=hyperacusis (noise sensitivity)
Why are taste changes relevant in testing the facial nerve?
Supplies taste sensation to anterior 2/3 of tongue
What are the two aspects of testing the vestibulocochlear VIII nerve? (2)
- Hearing
- Vestibular
What are the 3 hearing tests for testing the vestibulocochlear VIII nerve?
- Gross hearing
- Rhinne’s test
- Weber’s test
How is the test for gross hearing carried out? (5)
- Mouth 15cm from ear
- Whisper 99
- Mask ear not being tested by making rubbing sounds
- Ask them to repeat back
- If can hear, assess at 60cm
What size tuning fork is used to carry out Rhinne’s/Weber’s test?
512hz
How is Rhinne’s test carried out? (4)
- Tap fork and put base on mastoid process (bony process)
- Ask if can hear (bone conduction) then to say when they stop hearing
- Move 1cm away from external auditory process (air conduction) : ask if can hear better?
- Do in other ear
What is a positive Rhine’s test? And what 2 hearing states produce it?
Air conduction better than bone conduction
- Normal hearing
- Neurosensory hearing loss
Why does neurosensory hearing loss produce a positive Rhinne’s test?
All hearing reduced, so air conduction still better than bone relatively
Why does conductive hearing loss produce a negative Rhinne’s test?
Can’t hear physically, so air conduction bad in affected ear
How is Weber’s test carried out? (2)
- Place tuning fork in middle of forehead
- Ask which ear its heard louder in
What is a normal Weber’s test result?
Hearing equal on both sides
What would a conductive hearing loss produce in a Weber’s test and why? (2)
Louder in affected ear
- Bone conduction is better than air in that ear (not competing with ambient noise of room as can’t hear it)
What would a neurosensory hearing loss produce in a Weber’s test and why? (2)
Louder in normal air
As hearing impulses not conducted in affected ear at all to brain
What are the two tests of the vestibular system? (2)
- Unterberger test
- Head thrust
What reflex does the head thrust test test?
Vestibular-Ocular reflex
How is the unterberger test carried out? (2)
- Ask patient to march on the spot with arms outstretched and eyes closed
- Positive: patient rotates towards the side of the vestibular lesion
How is the head thrust test carried out to test for the vestibulocochlear VIII nerve? (5)
- Ask if neck pain?
- If not then hold head with one hand covering each ear
- Ask patient to look at nose
- Turn sharply to one side then the other
- Normal: fixation on nose maintained
What would the head thrust test in a vestibulocochlear loss of function patient result be? (2)
- Eyes will move in direction of the head (loss of fixation)
- Corrective refixation saccade towards nose
What are the tests for the glossopharyneal IX and vagus X nerves? (4)
- Gag reflex (mention don’t do)
- Uvula inspection (aah and symmetry)
- Cough
- Swallow
When assessing the glossopharyneal IX and vagus X nerves what are abnormal findings in the uvula?
- Deviation away from side of lesion
- Aah: uvula observed better when moving upwards
What type of cough indicates a CNIX or CNV problem?
Bovine cough
What type of swallow indicates a CNIX or CNV problem? (2)
- Delayed
- Coughing during
What are the tests for the XI accessory nerve? And what actions carry them out? (2)
- Trapezius power: ask patient to shrug shoulders against resistance
- Sternocleidomastoid power: ask patient to turn head against resistance (your hand on cheek)
A left weak sternocleidomastoid indicates a lesion on which side?
Right: contralateral control
How is the Hypoglossal XII nerve tested? (3)
- Tongue fasiculations and wasting
- Tongue deviation?
- Put finger on cheek, ask patient to push tongue against it
What side does a tongue deviate towards?
The side of the lesion
