Neurological OSCE overview part 2

Cranial nerves

General observation

• Ptosis (3)
• Facial droop or asymmetry (7)
• Hoarse voice (10)
• Articulation of words, dysarthria (5,7,10,12)
• Abnormal eye position (3,4,6)
• Abnormal or asymmetrical pupils (2,3, sympathetic and parasympathetic)

Cranial nerve 1 - Olfactory nerve

• Ask the patient about changes in or absence of sense of smell

Cranial nerve 2 - Optic nerve

• Examination with ophthalmoscope
• Papilloedema
• Optic atrophy
• Maculopathy
• Hypertensive or diabetic retinopathy

• Visual acuity with Snellen's chart
• Allow the patient to use glasses
• Ask the patient to read a Snellen eye chart with each eye
• Record the smallest line the patient can read for each eye
• Visual acuity is reported as a pair fo numbers (20/20) where the first number represents how far the patient is from the chart and the second number is the distance from which the 'normal

• Visual fields
• Position yourself at eye level a metre or so in front of the patient and ask him/her to look into your eyes
• Hold your hands out to the sides halfway between you and the patient and wriggle a finger on both hands asking the patient to indicate which side he/she sees the finger move; if the patient only sees one side this indicates a lateral field defect or sensory neglect on that side
• Test the four quadrants of each eye while asking the patient to cover the opposite eye comparing with your own fields of vision for the appropriate eye

• Test pupillary reactions
• Ask the patient to look into the distance
• Shine a bright light obliquely into each pupil in turn
• Look for both the direct (same eye) and consensual (other eye) reactions
• Test accommodation
• Hold your finger about 10cm from the patient's nose
• Ask him/her to look into the distance and then at your finger
• Look for constriction of the pupil and convergence of the eyes to near vision

Cranial nerve 3 - Oculomotor nerve

• Look for ptosis
• Test extraocular movements (superior, medial and inferior rector and inferior oblique muscles)
• Holding your finger about 1 metre in front of the patient, ask him/her to follow your finger with the eyes without moving the head
• Check horizontal, vertical, and oblique gaze using a cross or 'H' pattern, ask about diplopia
• Pause during upward and lateral gaze to check for nystagmus
• Test pupillary reactions to light

Cranial nerve 4 - Trochlear nerve (Superior oblique muscle)

• Inward and downward movement of eyes

Cranial nerve 6 - Abducens nerve (Lateral rectus muscle)

• Lateral eye movement

Cranial nerve 5 - Trigeminal nerve

• Motor
• Ask the patient to first open the mouth and then clench the teeth
• Palpate the temporal and masseter muscles as this is done
• Sensory
• On both sides, use cotton wool to test
• The forehead (olfactory division)
• The cheeks (maxillary division)
• The jaw (mandibular division)
• Corneal reflex
• Ask the patient to look up and away
• From the other side, touch the cornea (not sclera) lightly with a fine wisp of cotton wool
• Look for the normal blink reaction of both eyes
• Repeat on the other side

Cranial nerve 7 - Facial nerve

• Observe for any facial droop or asymmetry
• Ask the patient to do the following, noting any weakness of asymmetry
• Raise eyebrows
• Close both eyes tightly
• Smile or show the teeth
• Puff out the cheeks
• Central vs peripheral
• With an upper motor neurone lesion (stroke), crossover of innervation means function is preserved over the upper part of the face (forehead, eyebrows, eyelids)
• With a lower motor neurone lesion (Bell's palsy), the entire side of the face droops

Cranial nerve 8 - Vestibulocochlear nerve

• Rub your fingers together next to one ear while whispering a number in the other and ask the patient to tell you the number
• Repeat for the other side
• Weber's test
• Use a 512 Hz tuning fork
• Place the base of the vibrating tuning fork firmly on top of the patient's head
• Ask the patient where the sound appears to be coming from (normally in the midline)
• In sensorineural deafness there will be deafness in the affected ear
• In conductive deafness, the sound will be heard better in the deaf ear
• Rinne's test (to compare air and bone conduction)
• Use a 512 Hz tuning fork
• Place the base of the vibrating tuning fork against the mastoid bone behind the ear
• Whent he patient no longer hears the sound, hold the end of the fork near the patient's ear and ask if he or she can hear it now (air conduction is normally greater than bone conduction)
• In conductive deafness bone conduction is better than air conduction

Cranial nerve 9/10 - Glossopharyngeal and vagus

• Ask the patient to swallow a sip of water, look for choking or dribbling
• Ask the patient to say 'Agh', watching the movements of the soft palate and the pharynx. The uvula deviates away from the affected side
• Test the gag reflex (unconscious patient)
• Touch the back of the throat on the soft palate with an orange stick on each side
• It is normal to gag after each stimulus
• Ka La Mi
• Ka = 10
• La = 12
• Mi = 7

Cranial nerve 11 - Accessory

• From behind, look for wasting of the trapezius muscles
• Ask the patient to shrug the shoulders against resistance
• Ask the patient to turn the head against resistance
• Watch and palpate the sternocleidomastoid muscle on the opposite side

Cranial nerve 12 - Hypoglossal

• Look at the tongue for wasting or fasciculation (lower motor neurone lesion)
• Ask the patient to
• Protrude the tongue
• Move the tongue from side to side
• The tongue moves towards the side of any lesion