CN I: Olfactory
- Usually not tested.
- Rash, deformity of nose.
- Test each nostril with essence bottles of coffee, vanilla, peppermint.
CN II: Optic
- With patient wearing glasses, test each eye separately on eye chart/ card using an eye cover.
- Examine visual fields by confrontation by wiggling fingers 1 foot from pt’s ears, asking which they see move.
• Keep examiner’s head level with patient’s head.
- If poor visual acuity, map fields using fingers and a quadrant-covering card.
- Look into fundi.
CN III, IV, VI: Oculomotor, Trochlear, Abducens
- Look at pupils: shape, relative size, ptosis.
- Shine light in from the side to gauge pupil’s light reaction.
• Assess both direct and consensual responses.
• Assess afferent pupillary defect by moving light in arc from pupil to pupil. unne). Optionally: as do arc test, have pt place a flat hand extending vertically from his face, between his eyes, to act as a blinder so light can only go into one eye at a time.
- “Follow finger with eyes without moving head”: test the 6 cardinal points in an H pattern.
• Look for failure of movement, nystagmus [pause to check it during upward/ lateral gaze].
- Convergence by moving finger towards bridge of pt’s nose.
- Test accommodation by pt looking into distance, then a hat pin 30cm from nose.
- If MG suspected: pt. gazes upward at Dr’s finger to show worsening ptosis.
CN V: Trigeminal
- Corneal reflex: patient looks up and away.
• Touch cotton wool to other side.
• Look for blink in both eyes, ask if can sense it.
• Repeat other side [tests V sensory, VII motor].
- Facial sensation: sterile sharp item on forehead, cheek, jaw.
• Repeat with dull object. Ask to report sharp or dull.
• If abnormal, then temperature [heated/ water-cooled tuning fork], light touch [cotton].
- Motor: pt opens mouth, clenches teeth (pterygoids).
• Palpate temporal, masseter muscles as they clench.
- Test jaw jerk:
- Dr’s finger on tip of jaw.
- Grip patellar hammer halfway up shaft and tap Dr’s finger lightly.
- Usually nothing happens, or just a slight closure.
- If increased closure, think UMNL, esp pseudobulbar palsy.
CN VII: Facial
- Inspect facial droop or asymmetry.
- Facial expression muscles: pt looks up and wrinkles forehead.
• Examine wrinkling loss.
• Feel muscle strength by pushing down on each side [UMNL preserved because of bilateral innervation].
- Pt shuts eyes tightly: compare each side.
- Pt grins: compare nasolabial grooves.
- Also: frown, show teeth, puff out cheeks.
CN VIII: Vestibulocochlear (Hearing, Vestibular rarely)
- Dr’s hands arms length by each ear of pt.
• Rub one hand’s fingers with noise on one side, other hand noiselessly.
• Ask pt. which ear they hear you rubbing.
• Repeat with louder intensity, watching for abnormality.
- Weber’s test: Lateralization
• 512/ 1024 Hz [256 if deaf] vibrating fork on top of patients head/ forehead.
• “Where do you hear sound coming from?”
• Normal reply is midline.
- Rinne’s test: Air vs. Bone Conduction
• 512/ 1024 Hz [256 if deaf] vibrating fork on mastoid behind ear. Ask when stop hearing it.
• When stop hearing it, move to the patients ear so can hear it.
• Normal: air conduction [ear] better than bone conduction [mastoid].
- If indicated, look at external auditory canals, eardrums.
CN IX, X: Glossopharyngeal, Vagus
- Voice: hoarse or nasal.
- Pt. swallows, coughs (bovine cough: recurrent laryngeal).
- Examine palate for uvular displacement. (unilateral lesion: uvula drawn to normal side).
- Pt says “Ah”: symmetrical soft palate movement.
- Gag reflex [sensory IX, motor X]:
• Stimulate back of throat each side.
• Normal to gag each time.
CN XI: Accessory
- From behind, examine for trapezius atrophy, asymmetry.
- Pt. shrugs shoulders (trapezius).
- Pt. turns head against resistance: watch, palpate SCM on opposite side.
CN XII: Hypoglossal
- Listen to articulation.
- Inspect tongue in mouth for wasting, fasciculations.
- Protrude tongue: unilateral deviates to affected side.