Cranial Nerve Evaluation
Acoustic Neuroma and the Facial Nerve
Alyssa Capeling
Sara Holaly
Shawn McGinley
Kathy Olson
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Outline
Overview of cranial nerves
Cranial nerves affecting speech and hearing
Acoustic Neuroma
Cranial nerve VII
– Function
– Course and innervation
– Evaluation
• Overview
• Case study
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Case history
Audiologic assessment
Facial muscule evaluation
Taste
• Treatment options
• Summary
• References
Cranial Nerve Function
Love, R.J. & Webb, W.G. (2001). Neurology for the speech language pathologist (4th ed.). Boston, MD: Butterworth-Hinemann.
Cranial Nerve Function
Fix, J.D. (2000). High-yeild neuroanatomy (2nd ed.). Philadelphia, PA: Lippincott, Williams & Wilkins.
Cranial Nerves on the Web
http://faculty.washington.edu/chudler/cranial.html
http://www.meddean.luc.edu/MedEd/GrossAnatomy/h_n/cn/cn1/cn7.htm
Cranial Nerves for Speech
and Hearing
• Cranial Nerve V: Trigeminal
– Function: mastication and sensation (pain, temperature,
propioception, and touch) to face, teeth, gums, anterior 2/3 of
tongue, part of external ear canal, and tympanic membrane
• Also helps with flattening and tensing the soft palate for eustacian tube
opening and anterior and superior movement of the larynx
– Testing:
• Motor: feel masseter muscle as the patient bites down then relaxes;
have the patient open/close jaw against resistance, have the patient
move jaw laterally against resistance
• Sensory: firmly stroke cotton swab across different areas of the face
and tongue with the patient’s eyes closed
Cranial Nerves for Speech
and Hearing
• Cranial Nerve VII: Facial
– Function: controls movements of facial expression
(wrinkle forehead, close eyes, close mouth, pull back
corners of mouth, pull down corners of mouth), taste
on anterior tongue, stapedious reflex, controls
lacrimal gland, sublingual gland, submadibular gland,
and secretory glands of mouth and nasal cavity
• Also helps to move larynx up and back
– Testing:
• Motor: wrinkle forehead, look up at ceiling, close eyes as
tightly as possible, pucker lips, smile
• Sensory: have patient distinguish between different tastes
with eyes closed and tongue out of mouth
Cranial Nerves for Speech
and Hearing
• Cranial Nerve VIII: Vestibulocochlear
– Function: sound sensitivity, maintain equilibrium
– Testing:
• Hearing: audiologic testing
– SLP may do screening, and neurologist may use tuning forks to
test acuity and lateralization
– Audiologists perform complete diagnostic testing
• Equilibium: patient interview (may complain of tinnitus and/or
dizziness)
– Audiologists may perform ENG (electronystagmography) testing
and ABR (Auditory Brainstem Response) testing
– ENTs may order MRIs (magnetic resonance imaging)
Cranial Nerves for Speech
and Hearing
• Cranial Nerve IX: Glossopharyngeal
– Function: helps to clear the pharynx during swallowing
via dialation of the pharynx and elevation of the larynx;
controls taste on the posterior 1/3 of the tongue, assists
with pharyngeal gag, activates and regulates secretion
from the parotid gland
– Testing:
• Difficult to distinguish from CN X
• Sensory: test gag reflex by rubbing posterior pharyngeal wall
• Motor: swallowing assessment
Cranial Nerves for Speech
and Hearing
• Cranial Nerve X: Vagus
– Function: controls muscles of phonation and swallowing,
innervates cardiac and smooth muchles of esophagus,
stomach, and intestine, mediates sensation of visceral muscles
of pharynx, larynx, epiglottis, throax, and abdomen, controls
taste in pharynx and epiglottis, controls intrinsic muscles of
larynx, controls palatal function
• Recurrent laryngeal branch: intrinsic muscles of larynx except
cricothyroid
• Superior laryngeal branch: innervates cricothyroid
– Testing:
• Palatal function: view at rest and during /a/, test gag reflex
• Laryngeal function: lanyngoscopy, voice assessment including
sustained /a/, perceptial assesssment of pitch and loudness, cough vs
coup, stress testing (counting), may do instrumental analysis,
Cranial Nerves for Speech
and Hearing
• Cranial Nerve XI: Spinal Accessory
– Function: help turn, tilt, rotate,
forward/backward movement of head, raise the
sternum, shrugging the shoulders
– Testing: have patient move head against
resistance, have patient shrug shoulders while
you push down
Cranial Nerves for Speech
and Hearing
• Cranial Nerve XII: Hypoglossal
– Function: controls shortening, narrowing, elongating,
and flattening of tongue via innervation of intrinsic
muscles of tongue, controls tongue protursion,
retraction, drawing up and back via innervation of the
extrinsic tongue muscles, and assists with elevation of
the hyoid
– Testing: look at the tongue at rest to look for atrophy,
look for fasiculations and involuntary movement, have
the patient protrude tongue, move it up and down,
corner to corner, test strength using resistance during
movement, listen to production of /t/, /d/, /t⌠/, /d3/, l/,
/n/, /i/, /j/, /k/, /g/
Acoustic Neuroma
• Definition: “…a benign tumor of Schwann cells that
affects the vestibulocochlear nerve (CN VIII).” (Fix,
2000, p. 81)
– May also effect CN V and CN VII
• Symptoms: unilateral hearing loss, tinnitus, vertigo,
nystagmus, nausea, vomiting
– If damage to CN VII: facial weakness, loss of corneal reflex
– If damage to CN V: paresthesia and loss of corneal reflex
• Diagnosis: MRI, ENG, and ABR
• Treatment: Surgical removal
– Full recovery is possible with small tumors
– If not diagnosed early, may become large and lead to damage
of CN VII and/or the brainstem during removal
Function of CN VII
• General Sensory:(afferent) carry sensation from the skin of the concha of
the auricle, and posibly supplement sensation from the wall of the EAM and
the external surface of the tympanic membrane
• Special Sensory: (afferent) taste sensation from the anterior two-thirds of
the tongue
• Branchial Motor: (efferent) supplies muscles of facial expression and the
stapedius, stylohyoid, and posterior belly of the digrastic muscles
• Visceral Motor: (parasympathetic efferent) for stimulation of the lacrimal,
submandibular, and sublingual glands as well as the mucous membrane of the
nose and hard and soft palates
Branches of CN VII that Supply Muscles of the Face and
Neck
Branch
Muscles Supplied
Nerve to Stapedius
Stapedius
Nerve to Posterior Belly of Digastric
Posterior Belly of Digastric
Nerve to Stylohyoid
Stylohyoid
Termoral
Frontalis, Occiptalis, Orbicularis Oculi,
Corrugator Supercilli, Procerus
Zygomatic
Obicularis Oculi
Buccal
Buccinator, Obicularis Oris, Nasalis,
Labator Labii Superioris, Levator Labii
Superioris Alaeque Nasi, Zygomaticus
Major and Minor, Levator Anguli Oris
Mandigular
Orbicularis Oris, Mentalis, Depressor
Anguli Oris, Depressor Labii Inferioris,
Risorius
Cervical
Platysma
Posterior Aurical
Occipitalis
General Examination Compnents of the Facial Nerve
• 1. Function of the muscles of
facial expression
• 2. Taste from the taste buds
• 3.Somatic sensation from the
external ear
• 4. Function of the stapedius
• 5. Secretomotor innervation of
the lacrimal and salivary glands
Case Study
• Patient: E. O.
Age: 68
• Prior Medical History
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Onset of hearing loss: January 1986
Diagnosis of Acoustic Neuroma: June 2002
Date of Surgical Tumor Removal: July 31,2002
Speech Tx history:
• In patient acute care: primary focus swallowing
• In patient rehab: primary focus oral motor exercises
• Home Health (4 weeks): Oral motor exercises and
swallowing strategies
• Out patient: Oral motor exercises, speech articulation,
electrostimulation of facial muscles by physical therapy
Cranial Nerve VII
The Facial Nerve
Case Study
• Reported symptoms:
– Immediately post surgery
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Unable to swallow – PEG tube removed in September
Unable to speak due to facial weakness
Severe drooping of left side of face, “crooked mouth”
Tongue felt “frozen and spotty”
Unable to blink eye
Ocassional blurriness
Balance disturbances
Decreased tearing in left eye
– Improvements 3 months post surgery
• Increased facial movement
• Easier to eat/swallow
• Improved speech
Acoustic Reflex Testing
• The Acoustic Reflex: A bilateral
contraction of the stapedius
muscles in response to loud
sounds (80 dB SPL or above for
people with normal hearing)
• Testing is conducted at 500 Hz,
1000 Hz, and 2000 Hz by using
a 226 Hz probe tone to measure
changes in immittance
• Purposes of the Acoustic Reflex:
– protection from loud sounds
– Attenuates low frequency sounds
and helps with our perception by
reducing bodily noise.
A
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Acoustic Reflex Responses
• Shawn’s Response Levels
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Right Ipsilateral (Stimulus and Probe Right) 85 dB SPL
Right Contralateral (Stimulus Right, Probe Left) 90 dB SPL
Left Ipsilateral (Stimulus and Probe Left) 85 dB SPL
Left Contralateral (Stimulus Left, Probe Right) 90 dB SPL
• E.O.’s Response Levels
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Right Ipsilateral: Present at expected levels
Right Contralateral: Absent
Left Ipsilateral: Absent
Left Contralateral: Absent
• Patient with Left Facial Nerve Disorder Only
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Right Ipsilateral: Present at expected levels
Right Contralteral: Absent
Left Ipsilateral: Absent
Left Contralateral: Present at expected levels
Examing the Function of the Muscles of Facial Expression
Muscle
Task
Occipitofrontalis
Raise eyebrows
Orbicularis Oculi
Close eyes tightly
Obicularis Oris
Approximate lips
Zygomaticus Minor
Protrude upper uip (pucker)
Lebator Anguli Oris
Lift upper border of lip on left
Zygomaticus Major
Raise later angles of lips (smile)
Buccinator
Approximate & compress lips (clinician
can’t open)
Mentalis
Rase and protrude lower lip (pout)
Temporalis Masseter
Close jaw tightly
Pterygoid Lateralis and Medialis left
Move jaw laterally to the left
Pterygoid Lateralis and Medialis right
Move jaw laterally to the right
Examing the Function of the Muscles of Facial Expression:
Zygomaticus Major
Examing the Function of the Muscles of Facial Expression:
Zygomaticus Minor
Ra
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Ra
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Facial Nerve Responses
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Strength of Response
2
Ap
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Examing the Function of the Muscles of Facial Expression
3
Strength of Facial Nerve Response as a Function of Time
Blue: post-op.
Purple: 3 months post-op
1 = No visible response
2= Trace response
3= Functional response
0
Distribution of Change in Responses (from immediately
post op. to 3 months post)
No change in
response
36%
Improved from
"Trace response"
to "Functional
response"
9%
Improved from
"No Visible
Response" to
"Trace
Response"
55%
Examing Taste from the Taste Buds
• Four basic modalities of taste
– Sweet vs. salty
– Bitter and sour
• Protrude tongue
• One side swabbed with solution
– point to taste modality
• Other side swabbed
– Compared with first side
• Rinse with water
• Repeat with next taste
Treatment Options
• Oral Motor Exercises
• Articulation Drill
• Occupational and Physical Therapies
• Surgical Options
Summary
• Cranial Nerves for Speech and Hearing
• Acoustic Neuroma
• Facial Nerve
• Case Study
References
Bhatnager, S.C. & Andy, O.J. (1995). Neuroscience for the study of communication disorders. Baltimlore, MD: Williams &
Wilkins.
Facial Nerve. (n.d.). Retrieved October 22, 2002, from http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/
h_n/cn/cn1/cn7.htm
Fix, J.D. (2000). High-yeild neuroanatomy (2nd ed.). Philadelphia, PA: Lippincott, Williams & Wilkins.
Garrison, D. W. (1986). Cranial nerves: A systems Approach. Springfield, IL: Charles C. Thomas.
Love, R.J. & Webb, W.G. (2001). Neurology for the speech language pathologist (4th ed.). Boston, MD: ButterworthHinemann.
Nelson, M.A. & Hodge, M.M. (2000). Effects of facial paralysis and audiovisual information on stop place identification
[electronic version]. Journal of Speech, Language, and Hearing Research, 43, 158-171.
Neuroscience for Kids – Cranial Nerves. (n.d.). Retrieved September 6, 2002, from http://faculty.washington.edu/
chudler/cranial.html.
Pauwels, L.W., Akesson, E.J., Stewart, P.A., Spacey, S.D. (2002). Cranial nerves in health and disease (2nd ed.). Hamilton,
Ontario: BC Decker Inc.
Wiederholt, W.C. (1995). Neurology for the non-neurologists (3rd ed.). Philadelphia, PA: W.B. Sanders Company.
Yokoyama, T., Nishizawa, K., Sugiyama, K., & Yokota, N. (1999). Intraoperative evoked facial muscle responses and
recovery process of the facial nerve in acoustic neuroma surgery [electronic version]. British Journal of Neuroscience,
13, 570-575.