Cranial Nerve Examination

Introduction0/5

• Greetings
• Hand wash
• Verify the patient's identity using at least two or three details
• Explanation
• Consent

CN 1: Olfactory0/1

• Ask any change to sense of smell or difficulty smelling

CN 2: Optic0/9

• Visual acuity
• Pupils and responses
  • Symmetry~1:20 people have asymmetrical pupils normally
  • Response to light
    • Ipsilateral (direct)
    • Contralateral (consensual)
    • Shines light from side of the eyeNot in front, to avoid testing accommodation
  • Accommodation reflexPlace object ~20cm from eyes, ask patient to look at wall then object
• Visual fields: Assess for 10, 2, 8 and 4 o' clock positions in both eyesScreening test for hemianopia / quadrantanopia

CN 3, 4, 6: Oculomotor, trochlear, abducens0/3

• Do an H shape with your finger and ask the patient to follow
• (optional) place hand gently on patient's chin to stop head from moving
• Ask the patient to comment on diplopia, and you can comment on abnormal movements of the pupil(s) if there are any

CN 5: Trigeminal0/6

• Assess sensory with monofilament / cotton / pinprick (whichever available) for:
  • V1
  • V2
  • V3
  • Ask if it feels normal and same on both sides (don't just ask if they can feel it)
• Assess for motor with muscles of mastication: Put your hand on temporomandibular joint (TMJ) or temporal fossa and ask them to clench their teeth

CN 7: Facial0/7

• Comment on symmetry
• Movement
  • Eyebrows up
  • Eyes tight shut
  • Puff out cheeks
  • Bare teeth / smile
• Ask about loss or change in sensation on face

CN 8: Acoustic0/5

• Vestibular component: Dix-Hallpike manoeuvrePositive test: nystagmus after latent period, waxing then waning. No latent period or persistent nystagmus suggests central lesion
• Cochlear component
  • Cover one ear and whisper a number and ask them to repeat it
  • Rinne testNormally, air conduction > bone conduction. Rinné negative in conduction deafness
  • Weber's testSound localizes to normal ear in nerve deafness, to affected ear in conduction deafness

CN 9 and 10: Glossopharyngeal & Vagus0/3

• Observe uvulaShould lift symmetrically. Unilateral weakness deviates away from lesion
• Explain gag reflex properly
• Assess for gag reflexImportant for swallow and risk of aspiration

CN 11: Accessory0/2

• Shoulder shrug and neck turning. Then observe for symmetry / range of movement / muscle bulk
• Do above again while resistingTest SCM strength by resisting head turn

CN 12: Hypoglossal0/2

• Tongue movementsTongue will deviate towards the lesion
• (Optional but good) assess tongue strength by asking the patient to press their tongue against the inside of their cheek while you apply pressure from the outside with your hand.

• Wash hands