Exam 3 Flashcards
Huntington's to cranial nerves
what is the series of events involved in auditory conduction?
sound wave strike ear drum
ossicles move, causing vibration of the membrane at the opening of the upper chamber
movements of the fluid in the upper chamber
vibration of the basilar membrane and attached hair cells
hairs bend bc the tips are embedded in the immobile tectorial membrane, hair cells depolarize
cochlear nerve endings activated
what is the pathway for auditory info from the cochlear nuclei?
medial geniculate body–> primary auditory cortex (A1)
what is the inferior colliculus responsible for?
auditory info integrated from both ears
detection of the location of sounds
t/f: the inf colliculus elicits eye movement towards the sound via sup olive
true
t/f: the reticular formation is responsible for the activating affect of sounds on the CNS
true
what is the primary auditory cortex (A1) responsible for?
conscious awareness of the intensity of sounds
t/f: the primary auditory cortex has a map of where sound is processed depending on the frequency of sound
true
what is the secondary auditory cortex (A2) responsible for?
compares w/memories of other sounds
categorizes sounds (music, speech, calling you etc)
where is Wernicke’s area located?
posterior portion of the secondary auditory cortex
only in the L hemisphere, no BL
what is Wernicke’s area responsible for?
comprehension of spoken language
can someone with a lesion to Wernicke’s area still read and speak?
yes!
what is conductive hearing loss?
transmission of vibration is limited from the outer/middle ear to the inner ear
limited transmission of vibration/sound
what is the most common cause of conductive hearing loss?
excessive earwax
what kind of hearing loss is caused by otitis media?
conductive hearing loss
what is otitis media?
inflammation of the middle ear causing restricted ossicles
what is sensorineural hearing loss?
damage to the receptors cells of the cochlear nerve causes hearing loss
is sensorineural or conductive hearing loss more common?
conductive hearing loss
what can cause sensorineural hearing loss?
acoustic trauma
ototoxic drugs
Meniere’s disease
acoustic neuroma
what is acoustic trauma?
ear exposed to repetitive noise for prolonged period of time (ie working in a loud environment for whole life)
what are ototixic drugs?
drugs that are toxic to the auditory system
high dose aspirin or acetaminophen
one of the most commonly used diuretics
what is an acoustic neuroma?
benign tumor of the Schwann cells surrounding CN 8
tumor on the acoustic nerve that can grow and wipe out vestibular nerve
t/f: surgery to remove an acoustic neuroma improves symptoms of the vestibulocochlear system
false, the surgery leaves lingering symptoms in the vestibular system
what is tinnitus?
ringing in the ears
when is tinnitus normal?
when sitting in complete silence and the ringing lasts only a couple of seconds
what can cause tinnitis?
meds, stimulation of auditory receptors, or central sensitization following deafferentation
when someone has unilateral hearing loss, do we expect them to be able to clearly locate sounds?
no
what is Ramsey-Hunt syndrome?
CN 7 and 8 disease caused by varicella zoster infection (shingles)
acute facial paralysis w/ear p! and blisters/rash
balance issues, gaze stability impairment, vertigo, hearing impairment, and gait issues
what age group is typically affected by Ramsey Hunt syndrome?
> 60 years old
can pts recover from Ramsey-Hunt syndrome?
in mild-moderate cases they can fully recover
what is the special sensory fxn of the glossopharyngeal nerve (CN 9)? what is the associated nucleus?
afferents for taste from the post 1/3 of the tongue
spinal trigeminal nucleus
what is the somatosensory fxn of the glossopharyngeal nerve (CN 9)? what is the associated nucleus?
afferents fom soft palate, pharynx, and post 1/3 of the tongue, middle ear, and post external ear canal
spinal trigeminal nucleus
what is the motor fxn of the glossopharyngeal nerve (CN 9)? what is the associated nucleus?
efferent to one one muscle (stylopharyngeus) in the pharynx
nucleus ambiguus (in the medulla)
what is the parasympathetic fxn of the glossopharyngeal nerve (CN 9)? what is the associated nucleus?
efferent to parotid gland
inf salivatory nucleus
what is the reflex fxn of the glossopharyngeal nerve (CN 9)? what is the associated nucleus?
afferent limb of the gag and swallowing reflexes
solitary nucleus
what does the stylopharyngeus do?
elevation of the larynx and pharynx for speech production and swallowing
what CN is the efferent of the reflex to the parotid gland?
CN 10
what CN is the afferent of the reflex to the parotid gland?
CN 9
what are the consequences of CN 9 dysfxn?
reduced sensation over the post 1/3 tongue, palate, and pharynx
impaired gustation (taste) over post 1/3 tongue and palate
dysphagia
loss of carotid sinus reflex
absent gag reflex
parotid gland dysfxn
what is the somatosensory fxn of the vagus nerve (CN 10)? what is the associated nucleus?
afferents from pharynx, larynx, and skin in center of external ear
spinal trigeminal nucleus
what is the motor fxn of the vagus nerve (CN 10)? what is the associated nucleus?
efferents to muscles of the pharynx and larynx
nucleus ambiguus
what is the autonomic fxn of the vagus nerve (CN 10)? what is the associated nucleus?
afferent from pharynx, larynx, thorax, and abdomen
sup solitary nucleus
what is the parasympathetic fxn of the vagus nerve (CN 10)? what is the associated nucleus?
efferents to smooth muscles and glands in the pharynx, larynx, thorax, and abdomen
nucleus ambiguus
what is the reflex fxn of the vagus nerve (CN 10)? what is the associated nucleus?
efferent limb of gag and swallowing reflexes
dorsal motor nucleus
does the vagus nerve speed up or slow down the HR and contractility of the heart?
slows it down
what is the gag reflex?
touching of the pharynx elicits contraction of the pharyngeal muscles
what is the afferent limb of the gag reflex?
glossopharyngeal nerve (CN 9)
what is the efferent limb of the gag reflex?
vagus nerve (CN 10)
what is the swallowing reflex?
food touching the entrance of the pharynx elicits movement of the soft palate and contraction of the pharyngeal muscles
what is the afferent limb of the swallowing reflex?
glossopharyngeal nerve (CN 9)
what is the efferent limb of the swallowing reflex?
vagus nerve (CN 10)
what are the consequences of CN 10 dysfxn?
dysarthria
dysphagia
poor digestion
assymetric elevation of the palate
hoarseness
loss of gag and swallowing reflexes
uvula deviation
why is there poor digestion in CN 10 dysnfxn?
the efferent CN 10 facilitates digestion
decreased digestive enzymes and peristalsis
why does the uvula deviate in CN 10 dysfxn?
CN 10 participates in palate elevation
in CN 10 dysnfxn, uvula deviation is ___ to the lesion
contralateral
in CN 10 dysnfxn, soft palate depression is ___ to the lesion
ipsilateral (lower palate of the affected side)
what does a LMN lesion of CN 11 (spinal accessory) result in?
flaccid paralysis of SCM an straps ipsilateral to the lesion
what does an UMN lesion (corticobrainstem lesion) of CN 11 (spinal accessory) result in?
paresis due to bilateral cortical innervation
hypertonicity of the SCM and traps
what is the normal fxn of CN 12?
sticking tongue straight out
what does dysfxn of CN 12 result in?
atrophy of tongue and deviation to the weaker side
difficulty speaking and swallowing
t/f: CN 12 innervates intrinsic and extrinsic muscles of the tongue
true
what would result from an UMN lesion (corticobrainstem lesion) of CN 12?
tongue deviates to the side contralateral to the lesion
weakness is contralateral
with a L UMN lesion of CN 12, which side would be weak? which way would the tongue deviate?
R sided weakness
R tongue deviation
t/f: the corticobrainstem tract for CN 12 is bilateral
false, it only projects contralaterally
what would result from a LMN lesion of CN 12?
tongue deviates to the side ipsilateral to the lesion
ipsilateral weakness
with a L LMN lesion of CN 12, which side would be weak? which way would the tongue deviate?
L sided weakness
L tongue deviation
t/f: both UMN and LMN lesions of CN 12 will cause the tongue to deviate towards the side of weakness
true, the weakness will just be on different sides
can CN 12 dysfxn result in tongue atrophy, fasciculation, or tremors?
yes
what disorder commonly has fasciculation and atrophy of the tongue?
ALS
what disorders commonly have tremors of the tongue muscles?
PD and alcoholism
what are the 3 chronological stages of swallowing?
1) oral
2) pharyngeal/laryngeal
3) esophageal
what is involved in the oral stage of swallowing?
food in the mouth, lips closed
jaw, cheek, and tongue movements manipulate food
tongue moves food to the pharynx entrance
larynx closes
swallowing reflex triggered
what CN is involved in or oral phase when food is in the mouth with lips closed?
CN 7
what CNs are involved in the oral phase when the jaw, cheek, and tongue movements manipulate food?
CN 5, 7, 12
what CN is involved in the oral phase when the tongue moves food to the pharynx entrance?
CN 12
what CN is involved in the oral phase when the larynx closes?
CN 10
what CN is involved in the oral phase when the swallow reflex is triggered?
CN 9
what happens in the pharyngeal/laryngeal phase of swallowing?
food moves into the pharynx
soft palate rises to block food from the nasal cavity
epiglottis covers the trachea to prevent food from entering the lungs
peristalsis moves food to the entrance of the esophagus, sphincter opens, food moves into the esophagus
what CN is involved in the pharyngeal/laryngeal phase when food moves into the pharynx?
CN 9
what CN is involved in the pharyngeal/laryngeal phase when the soft palate rises to block food from the nasal cavity?
CN 10
what CN is involved in the pharyngeal/laryngeal phase when the epiglottis covers the trachea to prevent food from entering the lungs?
CN 10
what CN is involved in the pharyngeal/laryngeal phase when when peristalsis moves food to the entrance of the esophagus, sphincter opens, and food moves into the esophagus?
CN 10
what happens during the esophageal phase of swallowing?
peristalsis moves food into the stomach
what CN is involved in the esophageal phase of swallowing when peristalsis moves food into the stomach?
CN 10
the following are signs of what?
frequent aspiration, choking, lack of awareness of food in one side of the mouth
dysphagia
dysphagia results from dysfxn of what CNs?
5, 7, 9, 10, or 12
t/f: motor generation of sounds and articulation of words requires coordination of multiple CNs
true
dysarthria can result from a LMN of what CNs?
5, 7, 10, 12
what is spastic dysarthria and what does it result from?
hypertonicity of speech muscles resulting from an UMN lesion
which CNs are responsible for articulation of sound?
CN 5 (jaw)
CN 7 (lips)
CN 10 (soft palate and larynx)
CN 12 (tongue)
which CN is responsible for the generation of sounds?
CN 10 (larynx)
what are the peripheral causes of pathologic nystagmus?
vestibular apparatus or vestibular nerve
what are the central causes of pathologic nystagmus?
vestibular nuclei or vestibular cerebellum
what are the peripheral vestibular receptor disorders?
BPPV
unilateral vestibular disorders
bilateral vestibular disorders
Meniere’s disease
labyrinthine concussion (trauma)
perilymphatic fistula (hole)
sup canal dehiscence (SCD)
what is BPPV (benign paroxysmal positional vertigo)?
mechanical disorder caused by otoconia displacement from the macula of the utricle (where it should be) to the SCC (where it shouldn’t be) and becomes sensitive to gravity
what is the most common peripheral vestibular receptor disorder?
BPPV
where can particles be displaced in BPPV?
the posterior, horizontal, or anterior canals
attached to the cupula or sensory receptor
where is the most common place for particles to move to in BPPV?
posterior canals
which is more common, canalithiasis or cupulolithiasis?
canalithiasis
what is canalithiasis?
when the particles displace into the post, hor, or ant canals in BPPV
what is cupulolitiasis?
when the particles attach to the cupula or sensory receptor in BPPV
when do symptoms appear in BPPV?
when lying down or getting up
during movement as the crystals are moving
no symptoms once the crystals stop moving
how long does it typically take for the crystals to stop moving and symptoms to dissipate in BPPV?
less than 1 minute
what is the typical pt presentation in BPPV?
true spinning vertigo
triggered by lying down, rolling over, looking up, or bending over (pitch plane vs rolling movements)
short <1 minute attacks that start out light, get really bad b4 fading away (crescendo>descrescendo)
recent flu/cold, blow to the head
t/f: the odds of getting BPPV go up substantially w/w a blow to the head
true
how is BPPV diagnosed?
Dix Hallpike test (rotate the head 45 deg and quickly lie back of head off the table)
t/f: BPPV is very specific and easy to treat
true
what is the second most common location of BPPV?
horizontal canals (diagnosed with supine roll test)
what is a positive test for BPPV?
nystagmus provoked in the position that stimulates a given canal pair
what is the treatment for BPPV?
canalith repositioning maneuvers (Epley is one)
what are the unilateral peripheral disorders?
vestibular neuritis/labyrinthitis
Meniere’s disease
Ramsey Hunt
acoustic neuroma
3rd window (fistula, SCD)
labyrinthine concussion
does an acoustic neuroma cause hearing loss?
yes
what is the treatment for an acoustic neuroma?
taking out the tumor which leaves damage where the tumor was and can cause spinning following surgery as the brain adapts to the loss on that side
what is the typical presentation of a pt with a unilateral peripheral disorder?
outpt reports being “dizzy” and off balance w/blurry vision and some nausea
severe bout of consant acute vertigo following the flu
no vertigo now
what provoked unilateral peripheral disorders?
movement
what is the frequency of unilateral peripheral disorders?
episodic
what is the duration of symptoms in unilateral peripheral disorders?
only when moving
what is the intensity of symptoms in unilateral peripheral disorders?
mild
what unilateral peripheral vestibular condition is explained by EPISODIC acute condition, TRIAD of symptoms, unique TRIGGERS and DURATION (hrs to days)?
Meniere’s disease
what are the triad of symptoms in Meniere’s disease?
tinnitus, fluctuating hearing loss, aural fullness
what is the treatment for aural fullness?
diuretics to get rid of the excess fluid
what are the bilateral peripheral disorders?
sequential vestibular neuronitis
ototoxicity/vestibular ablation
autoimmune disorders/syphilis
t/f: new onset hearing loss is a red flag
true
what generally causes ototoxicity?
‘mycin drugs’
t/f: sepsis treated with antibiotics can save a pts life but wipe out the ear
true
what are the central processing or projection disorders?
MAV/MAD (migraine associated vertigo/dizziness
chronic dizziness (persistent perceptual postural dizziness-PPPD)
infarcts (ant vestibular aa, PICA, labyrinthine aa, AICA)
TIAs
CNS (MS, Chiari)
trauma (head injury, concussion)
do peripheral or central vestibular disorders generally result in milder continuous symptoms?
central
does the presence of any brainstem signs along with vertigo, nystagmus, or unsteadiness suggest a central or peripheral vestibular disorder?
central
what are some additional s/s of central vestibular disorder?
motor/sensory loss
Horner’s syndrome
pure vertical/direction changing nystagmus
diploplia
ataxia
dysarthria
does head tilt with anteropulsion and poor vertical orientation suggest a lesion where?
in the vestibular nuclei or above the sup vestibular nuclei
t/f: lateropulsion can be associated with Wallenburg’s syndrome or lesions of the spinocerebellar tracts
true
abnormal perception of vertical w/o vertigo is suggestive of what?
involvement of vestibulothalamocortical pathway or vestibular cortex
what is postural vertical?
the alignment of the body relative to gravity (fxn of the otoliths)
what are the 2 ways that otoliths contribute to postural vertical?
1) perception
2) postural reflexes
what pathway is responsible for perception of postural vertical?
otolith–> thalamus–> vestibular cortex
vestibulothalamocortical pathway
what pathway is responsible for postural reflexes?
otolith–> vestibulospinal and vestibulocollic tracts
is subjective visual vertical disorder central or peripheral?
peripheral
is postural vertical disorder central or peripheral?
central
what is lateropulsion?
pushing to the side
what is anteropulsion?
pushing forward
what is retropulsion?
pushing backward
what is postural vertical disorder?
central disorder where there is a misperception of postural vertical causing misalignment of the body relative to gravity
does otolith dysfxn impair subjective visual vertical or postural vertical?
subjective visual vertical
what is the triad of signs associated with otolith disorder?
1) lateral head tilt
2) skew deviation of the eyes
3) ocular tilt and rotation
what are nonvestibular causes of vestibular symptoms?
orthostatic hypotension (rare)
panic/anxiety attacks
dysequilibrium of aging
presbyastasis (inner ear weakness/couch potato ear)
t/f: nonvestibular causes of vertigo are harder to treat
true
what are nonorganic causes of vertigo?
aphysiologic or secondary gain (making it up)
describe the diagnostic process for vestibular disorders
hx taking
description of symptoms w/o using the word “dizzy”
description of symptoms, triggers, duration, severity, and timing
acute vs chronic
TTTH (timing, type, triggers, and hearing involvement)
how long do acute symptoms last?
<3 months
how long do chronic symptoms last?
> 3 months
if symptoms are worsened by linear acceleration such as elevators, escalators, or riding in the car, what should we suspect?
otolith dysfxn
if symptoms are worsened by angular acceleration such a as bending forward/backward, rolling over, or quick head movements, what should we suspect?
SCC dysfxn
if symptoms include blurry/bounding vision especially with movement, walking, or reading, what should we suspect?
VOR dysfxn, poor gaze stability
if a pt has difficulty looking from one object to another, tracking targets, or converging/diverging, what should we suspect?
oculomotor dysfxn
if a pt has increased imbalance in visual environment or activity, what should we suspect?
the pt has visual dependence for balance
what is the #1 cause of dizziness?
orthostatic hypotension
what is the #1 cause of vertigo?
BPPV
what does the central and peripheral diagnostic exam test?
smooth pursuits and end gaze nystagmus
cover cross test
head impulse test of the VOR
is the HINTS exam or an MRI more sensitive to central vs peripheral early on?
HINTS
is spontaneous nystagmus present with central or peripheral disorder?
central disorder and ACUTE peripheral disorder
what does the oculomotor and HINTS exam look for?
spontaneous nystagmus
nystagmus in eccentric gaze
central involvement (cover cross cover test)
head impulse test for the VOR
what does HINTS stand for?
Head Impulse Nystagmus Test of Skew
what does INFARCT stand for?
Impulse normal
Fast phase Alternating (look R, nystagmus R)
Refixation of Cover Test
what is a positive reorientation of Cover Test mean?
when you cover pt’s one eye and focus on your nose if the covered eye has to reorient to the nose
what results would indicate a benign HINTS exam?
abnormal HIT
fixed direction nystagmus
absent skew
what results would indicate dangerous HINTS exam?
any ONE of the following:
- normal HIT
- direction changing horizontal nystagmus present/untestable
- skew deviation present/untestable
what is measured in vestibular fxn testing?
eye movement
eye/neck muscle response
what is involved in vestibular fxn testing?
caloric testing
rotary testing
vestibular autorotation testing
C-VEMP
O-VEMP
how does electronystagmography measure nystagmus?
use of electrodes placed to record and measure each eye muscle response
how does videonystagmography measure nystagmus?
use of video infrared recordings to observe, record, and measure eye muscle responses
t/f: ENG and VNG record eye movement in response to a stimulus delivered to each vestibular apparatus
true
what is caloric testing?
a way to measure nystagmus using cold and warm water/air in each ear and measuring output of the eyes
what are normal results of caloric testing?
nystagmus in both eyes
when cold water/air is irrigated into the ears, what happens to the eyes?
the eyes move (horizontal nystagmus) away from the side of the stimulus
when warm water/air is irrigated into the ear, what happens to the eyes?
the eyes move towards the side of the stimulus
what does absent/reduced reactive eye movements suggest in caloric testing?
vestibular weakness (UVL) of the horizontal SCC of the side being stimulated
<__% difference bw the eyes is considered normal in caloric testing
25
increased responses in caloric testing usually signify what?
cerebellar disease
what results of caloric testing would indicate unilateral vestibular lesion?
decreased intensity of response in one ear of >25%
what results of caloric testing would indicate bilateral vestibular lesion?
no response/very weak response in both ears
what is the rotational chair test?
pt is rotated in a chair int he dark w/the eyes open and eye activity is recorded with ENG/VNG recording
measures phase and GAIN (ratio) of head:eye movements
what does reduced gain in rotational chair testing indicate?
decreased vestibular sensitivity
bilateral loss of vestibular fxn
what does abnormally large gain in rotational chair testing indicate?
central dysfxn
what are the indications for rotational chair testing?
suspected BL
pediatrics
can’t tolerate caloric testing
suspected to be aphysiologic
is ENG or rotational chair testing better for suspected BL involvement?
rotational chair testing
what is a vestibular autorotational test (VAT)
test performed in room light where the subject wears an accelerometer device on their head
subject asked to focus on target and move head at speeds greater than 2 Hz
records head and eye velocities
calculates VOR gains and phases
what is a VEMP?
Vestibular Evoked Myogenic Potentials
high intensity sounds stimulate the vestibular system in the absence of head movement
evaluates otolithic organs separate from the SCC
what is the anatomical difference be the otolith organs?
the UTRICLE supplies the ipsilateral superior oblique, superior rectus, medial rectus and control of the inf oblique and inf rectus via the sup vestibular nerve
the SACCULE supplies the ipsilateral SCM muscle via the inf vestibular nerve
what is the fxnal dif bw the otolith organs?
the UTRICLE is principally related to eye movement
the SACCULE plays a major role in control of postural adjustments
what is C-VEMP?
series of “clicks” used to stim each ear–>stim saccule–>inhibits SCM on ipsilateral side
the firing rate of the ipsilateral SCM is recorded using EMG
responses are compared bilaterally
what C-VEMP results indicate an abnormal test?
1) one side is 2x larger than the other
2) low amplitude
OR
3) absent
what does an abnormal C-VEMP indicate?
the saccule, inf vestibular nerve, integrity of the descending vestibular pathway for postural responses are abnormal
what is an O-VEMP?
series of “clicks” used to stim each ear–>stim utricle–>inhibits contralateral oblique
firing rate of the contralateral oblique is recorded using EMG
responses are compared bilaterally
what O-VEMP results indicate an abnormal test?
1) low amplitude
OR
2) absent
what does an abnormal O-VEMP indicate?
the integrity of the ascending VOR pathways, sup vestibular nerve, and utricle
how is subjective vertical tested?
pt asked to orient a rod to gravity (vertical) when in total darkness
the degree of off-axis tilt represents the torsion of the eye common in acute unilateral vestibular lesions
how are/should pts with BPPV be treated?
PT
how are/should pts with vestibular labyrinthitis/neuronitis, or Ramsey Hunt be treated?
with meds in acute case
with PT is uncompensated in chronic cases
how are/should pts with Meniere’s disease be treated?
diuretics and lifestyle changes
PT later and bw attacks
how are/should pts with vestibular migraines be treated?
with meds
how are/should pts with acoustic neuroma, fistula, or sup canal dehiscence be treated?
surgical removal/repair
PT after medical management
how are/should pts post-concussion/labyrinthine concussion be treated?
PT
neuro-opthamology (vision therapy)
medications
how are/should pts with central vestibular disorders (MS, stroke) be treated?
medical management
medications
PT
t/f: pts with Meniere’s disease, migraine, and infection must be treated b4 PT
true
