How to Perform a Cranial Nerve Examination

How to Perform a Cranial Nerve Examination

Performing a systematic neurological examination is a sophisticated clinical skill used to localize lesions within the nervous system.

This guide focuses on the Cranial Nerve Examination, the most common neurological assessment in an OSCE setting.

Introduction: The WIPER Initial Steps

Before testing specific nerves, ensure the patient is prepared and informed:

• W – Wash: Clean your hands using the WHO 7-step technique.

• I – Introduce: State your name and role.

• P – Permission & Pain: Explain that you will be testing various senses (sight, hearing, etc.) and facial movements. Ask if the patient has any pain in the head or neck.

• E – Exposure: The patient’s face and neck should be clearly visible.

• R – (Re)position: The patient should sit comfortably on the edge of the examination couch, at eye level with you.

Part 1: General Inspection

Observe the patient from the front for subtle neurological clues:

• Asymmetry: Look for facial drooping or eye deviations.

• Ptosis: Drooping of the upper eyelid (CN III palsy or Horner’s Syndrome).

• Speech: Listen for dysarthria (slurred speech) or dysphonia.

• Involuntary Movements: Note any tremors or muscle fasciculations.

Part 2: The 12 Cranial Nerves (Step-by-Step)

I – Olfactory (Smell)

• Test: Ask the patient if they have noticed any recent changes in their sense of smell. (Formal testing with scent bottles is rarely done in OSCEs).

II – Optic (Vision)

• Acuity: Test using a Snellen chart (one eye at a time).

• Fields: Compare the patient’s visual fields to your own via “confrontation.”

• Reflexes: Check the Pupillary Light Reflex (Direct and Consensual).

• Accommodation: Watch the pupils constrict as the patient focuses on a near object.

III, IV, & VI – Oculomotor, Trochlear, Abducens (Eye Movement)

• The “H” Test: Ask the patient to keep their head still and follow your finger with their eyes in an “H” pattern.

• Observe: Look for Nystagmus (flickering of the eyes) or Diplopia (double vision).

V – Trigeminal (Sensory & Motor)

• Sensory: Test light touch (cotton wool) in the Ophthalmic (V1), Maxillary (V2), and Mandibular (V3) distributions.

• Motor: Ask the patient to clench their teeth while you palpate the Masseter and Temporalis muscles.

VII – Facial (Motor)

• Ask the patient to:

  • Raise their eyebrows (look for forehead wrinkling).

  • Screw their eyes shut (try to gently open them).

  • Puff out their cheeks.

  • Show their teeth/smile.

VIII – Vestibulocochlear (Hearing)

• Whisper Test: Mask one ear and whisper a number into the other.

• Rinne’s & Weber’s Tests: Use a 512Hz tuning fork to differentiate between conductive and sensorineural hearing loss.

IX & X – Glossopharyngeal & Vagus

• Test: Ask the patient to open their mouth and say “Ahhh.” Look for symmetrical elevation of the uvula.

• Cough: Ask the patient to perform a “bovine cough.”

XI – Accessory (Shoulder & Neck)

• Trapezius: Ask the patient to shrug their shoulders against resistance.

• Sternocleidomastoid: Ask the patient to turn their head to each side against resistance.

XII – Hypoglossal (Tongue)

• Test: Ask the patient to protrude their tongue. Look for deviation (pointing toward the side of the lesion) or wasting/fasciculation.

Part 3: Completing the Examination

To finish your OSCE neurological assessment, state you would:

1. Fundoscopy: To look for papilloedema (raised intracranial pressure).

2. Peripheral Neuro Exam: Assess the upper and lower limbs (tone, power, reflexes, sensation).

3. Gait Assessment: Observe the patient walking to check for ataxia.

Summary of Common Cranial Nerve Lesions

Video Demonstrations

For a visual guide to the 12 cranial nerves:

• Cranial Nerve Examination Guide – Dr. James Gill

• Neuro OSCE: Testing Reflexes and Sensation