Cranial Nerve Exam
(Oral Motor Examination for Speech Pathologists)
Face: Facial Nerve (CN VII)
1. Examine structure at REST
(Facial symmetry- normal tone and little spontaneous movement. Neither drooping or fixed in posture). If the left side is drooping than this could be either a left lower motor (LMN) neuron lesion or right upper motor neuron lesion.
2. Wrinkle forehead or look at the ceiling without moving head (if the patient is unable to wrinkle the forehead so that both the lower side and upper side of the face is weak, this indicates a LMN CN VII lesion. If the forehead is spared so that the patient can wrinkle the forehead, this is a upper motor neuron (UMN) CN VII lesion (aka central lesion).
The following suggests ipsilateral LMN lesion of CN VII:
- Ptosis or eye drooping
- Facial droop
3. Pucker Lips- drooping or paralysis on right affects the right obicularis oris and vice versa.
4. Smile, Pulling Back Corners of mouth strongly- Weakness on right side affects the right platysma muscle and vice versa (produce /i-u/).
5. Frown: Show teeth and pull down hard with corners of mouth- weakness on right affects the right platysma muscle and vice versa.
Tongue: Hypoglossal Nerve (CN XII)
1. Examine tongue at rest
- Is tongue symmetrical? Normal size? If small are there symmetric or unilateral grooves or furrowing in the tongue presenting atrophy?
- Are fasciculations present? Look at the tongue only when the tongue is at REST IN THE MOUTH. To test have the patient move the tongue to each side then observe for individual movements along the surface, esp. along the lateral edges.
- Observe movements within the mouth while being maintained at rest. Is there a tremor? Involuntary movement?
- Medial Raphe concaving toward the right suggest right paralysis and vice versa
- Manipulate tongue with a tongue blade through a range of lateralization and elevation.
- Decreased tone or flaccidity suggest LMN lesions
- Increased tone or spasticity suggest UMN lesions
2. Tongue Retraction/Tone
Using tongue depressor, depress mid-posterior tongue dorsum at midline.
Assess Tone: decreased tone/resistance- suggests LMN or general debility
Increased tone- suggest spasticity (UMN)
3. Protrude/ Lateralization:
Have patient protrude tongue
- Deviation to the right suggests right genioglossus paralysis (ipsilateral LMN lesion or contralateral UMN lesion) and vice versa. The picture on the left shows the tongue deviating to the left side (the patient’s left). Therefore this patient has either a left lower motor neuron lesion or a right upper motor neuron lesion.
Assessing strength protrusion and lateralization by pushing tongue blade against tongue as patient offers resistance.
- Weakness suggests contralateral paralysis due to UMN lesion and or ipsilateral paralysis due to LMN lesion.
Have the patient open his mouth while the examiner puts his finger on the mandible
- Inability to retract and depress tongue suggest hypoglossus involvement
- Inability to draw the tongue upward or backward suggests styloglossus involvement
- Elevate tongue inside/outside mouth
- Lip licks (circular)
Jaw: Trigeminal Nerve (V)
1. Jaw at rest
- Identify if the jaw hangs lower than normal. This represents bilateral weakness of CN V.
- Involuntary movements- note clenching, opening, pulling to one side, or tremor like up and down movements
2. Bite (masseter)
* Masseter and temporalis muscle palpation: these muscles should have normal bulk when biting down and be symmetrical
* Atrophy or weakness suggests LMN lesion
3. Move jaw laterally:
* Inability to move jaw to the LEFT suggest paralysis of the right lateral pterygoid and vice versa
* Decreased range of lateral movement indicates paralysis of the right/left lateral ptergoids
4. Open mouth
- Jaw deviation to the left suggests weakness of the left lateral pterygoid
- Jaw deviation to the right suggest weakness of the right lateral pterygoid
5. Examiner provides resistance to the patient opening his mouth
- Decreased strength indicates weakness of the right and/or left lateral pterygoids
6. Speech evaluation via Diadochokinesis
Have patient produce repeatedly /pa/, /ta/ and /ka/
- Inability to produce /pa/ an average of 15-20 times in 3, five second trials suggests damage to the trigeminal nerve or CNS involvement affecting CN V
- Also consider possibility of CN VII involvement if labial weakness is present. Normal rate for /ta/ and /ka/ is 15-20 productions in 3 five second trials
VELUM: Vagus Nerve (X) and Glossopharyngeal (IX):
These two nerves are close in proximity and are typically damaged together. They are also usually tested together.
1. Velopharynx at rest
- Does the palate hang low in mouth? Does it rest on the tongue?
- Are palatal arches symmetrical (Normal palates are often asymmetrical especially following tonsillectomy and palatal surgery)
- Are there rhythmic or arrhythmic beating movements of the palate or uvula (myoclonus)
2. Velopharynx during movement. Prolong /a/
Palatal movement symmetrical?
- No elevation on right side of soft palate suggests paralysis on right side and vice versa
- Deviation of uvula to right- suggests paralysis on left and vice versa. The picture on the left shows a patient whose uvula deviates to the right. This implies a LEFT lower motor lesion of the vagus nerve. It could also represent a right upper motor neuron vagus nerve lesion.
- Say /a/ 5x, sharply
- Pharynx (IX) Sensory Gag (firmly stimulate faucial pillars, if no response stimulate posterior pharyngeal wall). Note whether gag response is asymmetrical. No gag does not indicate a swallow pathology as many patients normally do not have a gag. If the gag is present on one side and not on the opposite side, than this represents cranial nerve IX and X damage.
LARYNX : Vagus Nerve (X):
Consider vocal quality (hoarse, breathy, weak, pitch breaks)
1. Produce “coup de glotte” (sharp glottal stop or grunting sound)
- A weak cough but sharp glottal coup may reflect respiratory weakness
- A weak coup but normal cough tends to be associated with laryngeal weakness or combination respiratory/laryngeal weakness.
- Not testable
- Profound impairment- Patient attempts response with negligible result
- Severe- severely weak, soft or sluggish response
- Moderate- moderately weak, soft or sluggish response
- Mild- mildly weak, soft or sluggish response
- Normal- brisk, sharp and loud vocal fold adduction
2. Laryngeal excursion upon swallow
Voluntary Swallow: Laryngeal excursion on dry swallow
- Not testable
- Severely reduced- patient attempts to swallow, but has minimal laryngeal movement and does not complete the swallow
- Moderately reduced- patient completes the swallow, and some laryngeal movement is present, but the movement is moderately limited in degree of laryngeal elevation ( less than 1 full finger of movement); may also be delayed and or effortful.
- Mildly reduced; patient completes the swallow, and definite laryngeal movement coincides with the swallow, but the movement is mildly limited in degree of laryngeal elevation; may also be mildly delayed and/or effortful.
- Normal- patient completes the swallow; laryngeal movement is prompt and brisk; elevation is normal in range ( greater or equal to 1 full finger)
For more information, see the cranial nerve exam video
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