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Cranial Nerve EvaluationAcoustic Neuroma and the Facial
Nerve
Alyssa Capeling
Sara Holaly
Shawn McGinley
Kathy Olson
Outline• Overview of cranial nerves• Cranial nerves affecting speech and hearing• Acoustic Neuroma• Cranial nerve VII
– Function– Course and innervation– Evaluation
• Overview• Case study
– 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 (4 th ed.). Boston, MD: Butterworth-Hinemann.
Cranial Nerve Function
Fix, J.D. (2000). High-yeild neuroanatomy (2nd ed.). Philadelphia, PA: Lippincott, Williams & Wilkins.
http://faculty.washington.edu/chudler/cranial.html
http://www.meddean.luc.edu/MedEd/GrossAnatomy/h_n/cn/cn1/cn7.htm
Cranial Nerves on the Web
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 SuppliedNerve 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
– 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 VIIThe Facial Nerve
• Reported symptoms:– Immediately post surgery
• 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
Case Study
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.
AcoustIc
Reflex
Pathways
Acoustic Reflex Responses• Shawn’s Response Levels• 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• Right Ipsilateral: Present at expected levels• Right Contralateral: Absent• Left Ipsilateral: Absent• Left Contralateral: Absent
• Patient with Left Facial Nerve Disorder Only• 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 TaskOccipitofrontalis 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
Examing the Function of the Muscles of Facial Expression
Strength of Facial Nerve Response as a Function of Time
0
1
2
3
Raise
Eyebr
ows
Close
eyes
tigh
tly
Appro
ximat
e lip
s
Protru
de u
pper
lip (p
ucke
r)
Lift u
pper
bor
der o
f lip
on o
ne s
ide(s
neer
)
Raise
angle
of m
outh
up
and
later
ally
(sm
ile)
Appro
ximat
e an
d co
mpr
ess
lips
Raise
and
prot
urde
lower
lip (p
out)
Close
jaw ti
ghtly
Mov
e jaw
late
rally
righ
t
Mov
e jaw
late
rally
left
Facial Nerve Responses
Str
en
gth
of
Re
spo
nse
Blue: post-op.Purple: 3 months post-op1 = No visible response
2= Trace response3= Functional response
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 (4 th ed.). Boston, MD: Butterworth-Hinemann.
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 (2 nd ed.). Hamilton, Ontario: BC Decker Inc.
Wiederholt, W.C. (1995). Neurology for the non-neurologists (3 rd 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.