Cranial Nerves

Question 1

How do you test CN I?

Answer 1

Olfactory

• test smell in each nostril separately
• not usually tested unless other CNs are impaired

Question 2

How do you test CN II?

Answer 2

Optic

• visual acuity
• snellen chart (allow pt to wear glasses)
• 20/20 means pt can read at 20 ft with same accuracy as psn with normal vision

Question 3

How do you test CN III, IV, and VI?

Answer 3

Oculomotor, Trochlear, Abducens

• opening of eyelids
• pupillary reflex - pupil constricts in response to light
• consensual reflex - pupil constricts in response to light in other eye
• accommodation-convergence reflex - pt follows finger as it is brought toward nose (pupils should constrict)
• extraocular movement testing - letter ‘H’

Question 4

What does PERRLA stand for?

Answer 4

PE: Pupils Equal
R: Round
RL: Reactive to Light (direct and consensual)
A: responsive to Accommodation (near target)

Question 5

How do you test CN V?

Answer 5

Trigeminal

• Light touch sensation to the entire face with pts eyes closed
• pt bites down hard and palpate master muscle
• Corneal reflex

Question 6

How do you test CN VII?

Answer 6

Facial

• Crease up the forehead
• Keep eyes closed against resistance
• Reveal the teeth
• Puff out cheeks

Question 7

How do you test CN VIII?

Answer 7

Auditory
Use tuning fork to test:
-Conductive hearing - Air conduction and bone conduction - vibration through air and bone
- Sensorineural hearing - tests auditory nerve and hair cells in inner ear

Question 8

How should Rinnes test be interpreted? (tuning fork on mastoid and by ear)

Answer 8

• Normal hearing – air conduction (near ear) time should be twice as long as bone conduction (on mastoid) time
• Conductive hearing loss – if bone conduction time is longer than or equal to air conduction time
• Sensorineural hearing loss – if air conduction time is longer but not twice as long as bone conduction time

Question 9

How should Weber test be interpreted? (tuning fork on top of head)

Answer 9

• Normal hearing sound will be heard equally in both ears
• Conductive hearing loss the sound will be heard more/travels toward the poor ear
• Sensorineural hearing loss the sound will be heard more/travels toward the good ear
• So if sound is heard louder in one ear it is EITHER conductive loss in that ear or sensorineural loss in the other ear

Question 10

How do you test CN IX and X?

Answer 10

Glossopharyngeal and Vagus

- Gag reflex, swallowing, and taste

Question 11

How do you test CN XI?

Answer 11

Accessory

- Strength of traps and SCM

Question 12

How do you test CN XII?

Answer 12

Hypoglossal

• tongue movement and strength
• protrude tongue (deviates toward side of weakness) and move from side to side