1. CRANIAL NERVES
Assessment

2. CN I – Olfactory (Sensory)
Not often checked – impairment usually due to other causes (allergies, colds)
Impairment will also lead to decreased taste
Check each nostril independently with patient’s eyes closed
Use non-toxic substances such as
Coffee
Tobacco
Mild soap (Ivory)
Cloves

3. CN II – Optic (Sensory) Three tests
Visual acuity (sharpness or keenness)
Visual fields (peripheral vision)
Ophthalmoscope (internal eye inspection of optic fundus, where CNII joins the eye)

4. CN II – Optic: Checking visual acuity
Snellen chart may be used for greater accuracy
Simple acuity test
Patient covers one eye at a time
Hold up fingers and ask how many he/she sees
Or simply read a newspaper at arm’s length

5. CN II – Optic: Checking visual fields
Method called confrontation
Sit 2-3 feet from patient, your left eye aligned with patient’s right
Your eye acts as control, so you need good peripheral vision!
You close or cover your eye aligned with patient’s eye
Holding up your index finger, mid-distance between the patient and yourself, just beyond your own peripheral field, wiggle your finger as you slowly bring it into the visual field.
Ask the patient to tell you when he first sees your finger. It should be at about the same time that you see it.
Repeat the test to cover the entire visual field for each eye, which is to test at each of the six even-numbered positions on a clock's face.

6. CN II – Optic: Ophthalmoscope
Expensive piece of equipment
Use appropriately

7. All together now … Cranial Nerves III, IV, and VI Observation
III Oculomotor
IV Trochlear
VI Abducens
Observation
Examine the upper and lower lids by observation. Look to see that the opening between the eyelids, or the "palpebral fissures", are equal on both sides, and that each lid relates symmetrically to the cornea. Make sure to observe both upper and lower lids.
Next, observe the pupils in normal room light to see if they are symmetric.

8. Cranial Nerves III, IV, and VI (Motor)
Four tests
Direct Light Reflex
Consensual Light Reflex
Accommodation
Six Cardinal Fields of Gaze

9. Cranial Nerves III, IV, and VI
Direct Light Reflex
Each pupil should constrict briskly when the light strikes the pupil.
Move the light in from the temporal side.
Document the reaction in mm (e.g., 6mm  4mm).

10. Cranial Nerves III, IV, and VI
Consensual Light Reflex
Perform the procedure again, exactly as before for Direct Light Reflex… only this time watch the opposite pupil.
It should react the same as the pupil in which the light is shined.

11. Cranial Nerves III, IV, and VI
Accommodation - adaptation of the eyes for near vision
Ask the patient to focus on a distant light (e.g., a wall or door) at their eye level and maintain that gaze until directed otherwise.
Hold an object (pencil, penlight, finger) about 18" from the patient's nose.
Ask him to change his focus from the distant object to the closer one.
As he does so, observe his eyes as they converge (turn inward) and the pupils constrict.

12. Cranial Nerves III, IV, and VI
Document normal reactions as PERLA!
Pupils
Equally
Reactive to
Light and
Accommodation

13. Cranial Nerves III, IV, and VI
Document abnormal eye movements
Some key terms to know
Nystagmus: constant, involuntary, cyclical movement
Saccadic: jerky, rapid, intermittent movements
Tracking: lagging, catching up movement
Vergence: turning of one eye without reference to the other, which may indicate weakness of oblique muscles.

14. Cranial Nerves III, IV, and VI
Six Cardinal (primary) Fields of Gaze: tests for extraocular movement
Six fields correspond roughly to 12, 2, 4, 6, 8, 10 on a clock face
Hold an object (pen, penlight, finger) about 12" from the patient's nose.
Instruct the patient to keep his head still and to follow the object's movement to the six cardinal fields with his eyes only.
Slowly move the object through each vision field separately, observing both eyes simultaneously.

15. CN V – Trigeminal (Sensory AND Motor)
As the name suggests, the trigeminal nerve innervates 3 sections of the face:
ophthalmic
maxillary
mandibular

16. CN V – Trigeminal Sensory Assessment
Begin by assessing ability to sense light touch to the face.
Ask the patient to close his/her eyes and to tell you what he/she feels, and when and where he/she feels it.
Using a fine wisp of cotton or your fingertip, gently test the forehead, cheeks, and jaw, randomly and bilaterally.
The patient should be able to identify the same sensation bilaterally, and tell when and where he/she feels the touch.
If not, repeat the test using the sharp and blunt ends of a sterile pin to check sensitivity to pain.
Sensitivity to temperature may also be tested using test tubes with warm and cool water.

17. CN V – Trigeminal Corneal Reflex Test
Usually not done if light touch is intact
Instruct the patient to look up and away from you.
Approaching the patient laterally, out of his line of vision, and avoiding the eyelashes, touch the cornea lightly with a fine wisp of cotton.
Look for blinking of the eyes, the normal reaction to this stimulus.
Be aware that use of contact lenses frequently diminishes, or may even eliminate, the corneal reflex response.
The corneal reflex tests the afferent (sensory) arc of CN V, and the efferent (motor) arc of CN VII.

18. CN V – Trigeminal Motor Assessment
Ask the patient to clench his/her teeth.
While he/she is clinching, palpate the temporal muscles.
You should note symmetrical strength. Move your hands to the area of the masseter muscles and ask the patient to clench again.
Bilateral contraction should be equally strong.
To assess chewing ability, ask the patient to clench and unclench his/her jaws several times while you observe for distorted movements or asymmetry.

19. CN VII – Facial (Sensory and Motor)
Motor assessment
Observation during conversation
Facial symmetry during spontaneous expression
Wrinkling the nose
Smiling and frowning
Closing eyes
Grimacing
Intentional expression; ask the patient to
Raise and lower eyebrows
Squeeze eyes shut tightly
Smile showing teeth
Puff out cheeks

20. CN VII – Facial Sensory assessment
Usually not done unless problems are noted during motor assessment
CNVII responsible for taste on anterior 2/3 of the tongue
With patient’s eyes closed, check for recognition of common, easily distinguishable tastes such as chocolate or lemon

21. CN VIII – Acoustic (Sensory and Motor)
aka Vestibulocochlear nerve
Two branches
Vestibular nerve branch controls balance and equilibrium
Cochlear nerve branch controls hearing
Vestibular branch not usually checked unless several symptoms of abnormality exist
Vertigo
N/V
Nystagmus
Postural deviation
Pallor
Sweating
Hypotension

22. CN VIII – Acoustic Sensory assessment
To make a gross assessment of the cochlear division, begin by instructing the patient to close his eyes and tell you what he hears and in which ear.
Gently rub your fingers together about 6" away from first one ear, then the other, then both simultaneously.
If deficit is suggested, a more precise assessment may be done with a tuning fork.

23. CN IX & X – Sensory and Motor
CN IX Glossopharyngeal
CN X Vagus
Cranial nerves nine and ten are tested together, because they are closely associated and similar in function.
The motor aspect of the glossopharyngeal nerve innervates the muscle used to swallow.
Its sensory component supplies sensation to the pharynx and is responsible for taste perception on the posterior 1/3 of the tongue, and for salivation.

24. CN X – VAGUS! The vagus nerve controls:
swallowing
phonation (the process of uttering vocal sounds)
movement of the uvula and soft palate.
CN X also innervates the thoracic and abdominal visceral organs!
Carries sensory impulses from the GI tract, the heart, and the lungs

25. CN IX & X – Assessment
Begin assessment of these 2 nerves by inspecting the soft palate.
When the patient says "ah", the palate should rise promptly and symmetrically.
The uvula should NOT be used to assess symmetry, because there are many normally odd-shaped structures.

26. CN IX & X – Assessment
The gag reflex assesses the sensory component of CN IX, and the motor response of CN X.
Touch the posterior pharynx lightly with a cotton-tipped applicator.
Test the palatal reflex, stroke the posterior portion of the palate on each side with the applicator.
In both instances, the palate should elevate and a gag response should be induced.
However, remember that normal patients frequently manifest bilateral loss of the gag reflex, especially patients with a history of smoking or tobacco use.

27. CN XI – Spinal Accessory (Motor)
The spinal accessory nerve supplies the sternocleidomastoid muscles and the upper portion of the trapezius muscles.

28. CN XI – Spinal Accessory
To assess sternocleidomastoid strength, apply resistance to the jaw and have the patient try to turn his head to the side against your pressure.
To evaluate the trapezius, watch the patient shrug his shoulders, which should move at the same speed and with roughly the same extent of movement.
Next, ask the patient to shrug his shoulders upward while you try to hold them down.

29. CN XII – Hypoglossal (Motor)
Responsible for normal tongue movements.
First observe the tongue at rest on the floor of the mouth.
Look for:
asymmetry
deviation to one side
loss of bulk on one side
fasciculations (involuntary contractions, twitching)
Next, ask the patient to stick out his tongue.
It should protrude along the midline [the "median raphe" (midline crease) lines up with the notch between the "medial incisors" (two front teeth)].

30. CN XII – Hypoglossal
Finally, have the patient push his/her tongue as hard as he/she can against the inside of the cheek, while you push using your thumb against the outside of the cheek.
Compare right and left sides.
Remember that weakness pushing the tongue into the right cheek indicates an abnormality in the left hypoglossal nerve, and vice versa.