Central Vestibular System & Peripheral System Disorders- Lecture 12 Flashcards
vestibular nuclei complex
primary processor of vestibular input
connects incoming afferent info and motor output neurons
what does the vestibular nuclei complex have
4 major nuclei in the pons
extends into the medulla
what does the vestibular nuclei complex process
vestibular sensory input and extra vestibular proprioceptive, visual, tactile and auditory info
cerebellum
monitors vestibular performance and readjusts the central processing
major recipient of vestibular info from the nuclei
what do both the cerebellum and nuclei process
info in association with somatosensory, proprioceptive and visual input
vertebrobasilar arterial system
provides supply for both the peripheral and central vestibular system
when might clinical syndromes with vestibular components appear
after occlusions of the basilar artery and its branches
VSR
vestibular spinal reflex
vestibular spinal reflex
adjusts posture when the head is moved
anticipates a loss of balance and adjusts posture to maintain balance
abnormal VSR
difficulty with static or dynamic balance and the feeling of being off balance
age related changes with the vestibular system
increased difficulty with eyes closed activities
decreased ability to detect head position and motion
reduced number of receptor cells
BPPV
benign paroxysmal positional vertigo
what is BPPV
positional vertigo of short duration (up to one minute) which occurs when the pt lie down, sits up, rolls over in bed, looks up or bends over
what is BPPV caused by
otoconia from the otolith that have become misplaced within the semicircular canals
Hallpike-Dix position
20-30 degrees of cervical extension
45 degrees of rotation
what does the Hallpike-Dix position elicit
symptoms of vertigo within 1-40 secs
not lasting more than 60 sec
why does BPPV occur
head trauma
degeneration of the vestibular system
following ear surgery
dental work
virus
idiopathic
link to vitamin D deficiency
what will be seen in the dix hallpike position with BPPV
torsional nystagmus
pt’s will habituate with repetition
what else can BPPV be seen in
roll test position
roll test position
pt supine
30 degrees of flexion and 45 degrees of rotation
nystagmus will not be torsional
how can BPPV resolve
w/o treatment
usually b/w 6 mo-1 yr
how can BPPV be treated
epley/CRt within 1-3 visits
labyrinthitis
inflammation of the labyrinth including cochlea
what is labyrinthitis d/t
upper respiratory infection
flu
bacterial or viral infection occurring up to 2 weeks prior to onset of symptoms
acute symptoms of labyrinthitis
sudden onset of vertigo lasting days w/ nausea and vomiting common
pt may be bed ridden or hospitalized secondary to severe symptoms
labyrinthitis med
antivert or meclizine
may be used initially to surpress the vestibular system
decrease vertigo
when should meds be stopped –> labyrinthitis
prior to coming to therapy in order for compensation to occur
chronic sx –> labyrinthitis
imbalance and dizziness
when are symptoms worse –> labyrinthitis
head movement
busy visual stimuli
stress
fatigue
weather changes
altitude changes
illness
pts that recover on their own –> labyrinthitis
80%
pts that need treatment –> labyrinthitis
prolonged
vestibular rehab can speed up compensation
vestibular neuritis
inflammation of the vestibular nerve
sx of vestibular neuritis
same as labyrinthitis except hearing is spared
acoustic neuroma
slow growing benign tumor on CN8
overtime will compress on structures adjacent to it
first sx of acoustic neuroma
hearing loss
tinnitus
decreased vestibular fxn with impaired balance
acoustic neuroma has
no dizziness
CNS is able to gradually adapt in response to slow onset of sx and slow growing tumor
what is recommended for acoustic neuroma
surgery to remove tumor
risk of facial palsy and/or permanent hearing loss
gamma knife procedure –> acoustic neuroma
used for smaller tumors
stereotactic radiotherapy –> acoustic neuroma
used for small tumors
how do pts recover –> acoustic neuroma
without tx
vestibular rehab is successful for those who seek treatment
meniere’s/endolymphatic hydrops is caused by
alteration in production, flow, absorption or reabsorption of the inner ear fluids
underlying origin of meniere’s/endolymphatic hydrops
unknown
may be influenced by infection, abnormal response of the immune system or genetic tendency
sx of meniere’s/endolymphatic hydrops
vertigo lasting 20 min-12 hrs
sensory neural hearing loss
nausea
vomiting
diarrhea
sensory neural hearing loss
predominantly low frequency
tinnitus or fullness in ears
when do pts have episodes –> meniere’s/endolymphatic hydrops
one episode every hew years to weekly or daily episodes
what occurs after an episode –> meniere’s/endolymphatic hydrops
may or may not be residual sx
overtime residual sx may worsen –> become symptoms were able to treat
when does rehab become ineffective –> meniere’s/endolymphatic hydrops
no sx in between episodesq
tx for meniere’s/endolymphatic hydrops
diet changes
various surgeries
gentamycin injections
endolymphatic shunt
endolymphatic shunt
tube inserted into endolymphatic sac to facilitate drainage
superior canal dehiscence
thinning or opening in the bone overlying the superior (anterior) semicircular canal
symptoms of SCD
vertigo
oscillopsia caused by loud noise and activities that increase intracranial pressure
sensitivity to sound
fatigue
fullness in the ear
what does SCD create
a third area affected by pressure
fluid w/in the canal is moved by stimuli from pressure or sound
what is SCD caused by
developmental abnormality of thin, fragile bone over the superior canal
when do symptoms present SCD
following trauma or slow erosion of the bone over time
how is SCD diagnosed
CT
symptoms
clinical exam
how is SCD treated
surgery to reface the bone or plugging of the canal
perilymphatic fistula
rare condition
a tear or defect in the oval or round window that separates the inner and middle ear
changes in pressure that affect the middle ear will also affect the inner ear
when does perilymphatic fistula occur
following trauma or following rapid changes of intracranial or atmospheric pressure
sx perilymphatic fistula
vertigo
nausea
imbalance
when do symptoms increase perilymphatic fistula
pressure changes or altitude
exertion
tx perilymphatic fistula
strict bed rest or surgery
do not get better with therapy
ototoxicity
damage to hair cells of inner ear
what causes ototoxicity
drugs –> primarily gentamicin and other “mycin” drugs
esp if meds are delivered by IV for greater than 6 days
pt may not have –> ototoxicity
total loss of vestibular fxn
sx ototoxicity
imbalance
ataxia
oscillopsia
gaze instability with decreased or absent VOR
sx will be worse w/ –> ototoxicity
increased loss of hair cells
when will a pt have vertigo –> ototoxicity
damage is asymmetrical
vestibular rehab –> ototoxicity
focused on strengthening residual fxn or on substitution if there is total bilateral loss
TBI/head trauma can cause
both central and peripheral problems
sx –>TBI/head trauma
dependent on the area involved and the severity of central or peripheral injury
sx could include –> TBI/head trauma
dizziness, vertigo, imbalance, headache, migraine, short term memory deficit and motion sensitivity
vestibular rehab –> TBI/head trauma
prolonged
