OSCE Neuro Cranial Nerves

Question 1

What positioning is required for the cranial nerve examination?

Answer 1

Patient sitting on a chair or sitting on the side of the examination bed (i.e. with legs over the side of the bed)

Question 2

What does a general observation involve in a cranial nerve examination (5)?

Answer 2

Important to start with observations “from the end of the bed”
1. Conscious level
2. Any obvious distress
3. Presence of abnormal movements (such as tremor)
4. Limb posture/position
5. Quality of voice/presence of cough

Question 3

Explain how to test the hypoglossal nerve (CN XII)

Answer 3

Note: Motor
1. Open mouth wide and inspect of tongue (for wasting, fasciculations)

2. With tongue protruding, assesses symmetry and sideways movement

Question 4

Explain how to test the accessory nerve (CN XI)

Answer 4

Note: Motor
1. Assess power of shoulder shrug against resistance (Push down onto Trapezius muscles)

2. Assess power of lateral rotation of head (hand on each side of the jaw, patient resists the push of examiner - sternocleidomastoid muscles)

Question 5

How is the vestibulocochlear nerve (CNVIII) tested for the cranial nerve examination?

Answer 5

Note: Sensory
1. Hearing test (watch tick at the ear)
2. Rinne test (mastoid process to external ear)
3. Weber test (tuning fork onto the midline forehead

Question 6

Explain how the facial nerve (CN VII) is tested?

Answer 6

Note: Both sensory and motor, but only motor tested
1. Facial movements
a) Raise eyebrows
b) Show your teeth
c) Close eyes tightly and resist examiner opening
d) Blow out your cheeks and dont let me press them in

Question 7

Explain how the Olfactory nerve (CN I) is tested?

Answer 7

Easy
Inquires about any changes in sense of smell
(no other tests yet)

Question 8

What is the examination procedure for the Hypoglossal nerve (CNXII)?

Answer 8

1. Ask the patient to open their mouth and then inspect the tongue initially looking for any sign of muscle wasting or the presence of fasciculations.
2. Ask the patient to put out their tongue, and move it from side to side. Observe for symmetry and ability to move the tongue from side to side

Question 9

What is the examination procedure for the Accessory nerve (CNXI)?

Answer 9

1. Ask the patient to shrug their shoulders up against your resistance (place your hands on top of patient’s shoulders medially - over trapezius).
2. Ask the patient to turn their head laterally against resistance – place your hand on the patient’s jaw over the lateral aspect of the mandible.

Right sternocleidomastoid muscle: Turns head to the left
Left sternocleidomastoid muscle: Turns head to the right

Question 10

What are the normal findings of the hypoglossal nerve (CNXII)?

Answer 10

Normal findings: tongue protrudes in midline position, symmetrical movement from side to side

Question 11

In order to complete the cranial nerve examination, what other tests are performed?

Answer 11

Finishing the entire neurological exam by performing:
A lower limb neurological examination
An upper limb neurological examination

Question 12

What are the normal findings for the accessory nerve (CNXI)?

Answer 12

Normal findings: symmetrical power for both trapezius and sternocleidomastoid muscles; difficult to overcome patient’s movements.

Question 13

What are the normal findings for the olfactory nerve (CNI) ?

Answer 13

Normal findings: no report of loss of sense of smell.

Question 14

How is the Optic nerve (CNII) tested in the cranial nerve examination?

Answer 14

1. Visual acuity test
2. Visual Field test, maps the blind spot
3. Would perform fundoscopy to further examine the optic nerve, not assessed in OSCE)

Question 15

How are the Oculomotor nerve (CN III), Trochlear nerve (CN IV) and Abducens nerve (CN VI) tested in the cranial nerve examination?

Answer 15

1. Observation of pupils – size, shape, symmetry
2. Observation of upper eyelid position
3. Pupillary light reflexes:
   Consensual reflex
   Direct reflex
   Accommodation reflex
4. H pattern test - Movements of the eyes – 6 cardinal directions

Question 16

How is the trigeminal nerve (CN V) tested in the cranial nerve examination (5)?

Answer 16

1. Corneal reflex – describe the technique and what the reflex represents (positive/negative findings, neurological basis – including facial nerve component)
2. Assess facial sensation - (V1, V2, V3 divisions symmetrically)
3. Inspection, Palpation (muscle bulk) of masseters
4. Power of pterygoids (resist closing of the mouth - pushing jaw up)
5. Jaw jerk - central jaw reflex with hammer

Question 17

How is the hearing test conducted?

Answer 17

Hearing is tested by occluding one ear, and then test to see if they can hear a watch ticking (at least 60 cm away) in the other ear

If hearing loss is suspected i.e. the watch ticking is not heard, perform the Rinné and Weber tests to assess for the possible cause of the hearing loss

Question 18

What are the normal findings for the vestibulocochlear nerve (CN VII)?

Answer 18

Normal findings: able to hear whispered number; sound heard centrally during the Weber test; air
conduction better than bone conduction bilaterally (Rinné-positive)

Question 19

How are the Glossopharyngeal (CN IX) and Vagus nerves (CN X) tested in a cranial nerve examination (4)?

Answer 19

• Observe palate with penlight for symmetry
• Asks patient to say “Ahh” and comments on symmetry/asymmetry of soft palate (uvula position)
• Gag reflex ( Expected to describe the
  technique and what the reflex represents rather than perform it)
• Comment on quality of voice/cough (repeated here as a reminder of the cranial nerves involved)