Vestibular A&P Flashcards
T/F: all balance issues must have a vestibular component
false; vestibular function likely leads to a balance issue, but not all balance issues are vestibular in nature
T/F: balance training is vestibular training
false; balance training does not equal vestibular PT
what are the two major components of vestibular therapy
exercises and canalith repositioning
what do you do if you have evaluate a patient that experiences hearing issues alongside vestibular issues?
refer to ENT for further workup
what lies behind the ear drum?
the middle ear - the eustachian tube accesses the throat and the stirrup, hammer, and anvil can be found here
what is the bony labyrinth
a series of fluid-filled (perilymph) cavities (cochlea, vestibule, and SCCs)
what is unique about perilymph in terms of relevant pathology
the perilymph communicates with CSF; therefore, in NPH (weird, wet, and wobbly) we get the wobbly component due to the connection of perilymph with the CSF
what is the membranous labyrinth
a series of communicating sacs and ducts suspended in the bony labrynth, most notably the utricle and saccule
what are the utricle and saccule filled with?
endolymph
describe the anatomical end of a SCC
the SCC ends in an ampulla which houses a crista containing a cupula that directly impacts the hair cells
describe how hair cells are influences by movement and how it translates into neural sensory firing
When the hair cells (stereocilia) are bent towards the kinocilium (tall hair cell) firing rate increases and is excitatory. When the stereocilia are bent away, firing rate decreases and is inhibitory.
T/F: the SCC utilize otoconia to deflect hair cells
false; otoconia are found in the utricle and saccule but not the SCC sensory organs
otoliths respond to ____ and ____
linear motion and tilt
SCC respond to ____
angular motion aka rotation
describe the orientation of bilateral SCCs
SCCs are parallel to one another and horizontal canals are angled 30 degrees upward
what are otoliths
CaCO3 crystals suspended in the utricle and saccule that assist in sensing velocity changes and tilt (linear motion)
what does the saccule sense? the utricle?
saccule - saggital plane (tilt)
utricle - horizontal plane (acceleration)
what condition increases changes of developing BPPV
osteoporosis because the otoliths are made of CaCO3
otoliths move (a) in the direction of gravity (b) opposite of gravity
(a) in the direction of gravity
which artery supplies the vestibular system
the labyrinthine artery from AICA or basilar artery supplies the peripheral vestibular system
what are the branches of the labyrinthine artery
anterior vestibular artery and common cochlear artery
why is blood supply relevant to us as PTs?
we must know that the labyrinthine artery is highly susceptible to ischemia
the internal auditory canal contains what (3)
- vestibular and cochlear nerves
- facial nerve
- labyrinthine artery
T/F: the vestibular nerve fires in the absence of movement
true
what is the role of the CB in vestibular reflexes
the CB is NOT required for vestibular reflexes, but it calibrates them; therefore CB issues result in the inability to adapt making vestibular rehab difficult
patients with CB disorders exhibit ___ and ____
nystagmus and ataxia
which artery primarily supplies the central vestibular system
PICA off the basilar artery
what is effected in a PICA stroke
aka lateral medullary syndrome, a PICA stroke will damage vestibular nuclei and the inf CB resulting in purely central balance symptoms
what is effected in an AICA stroke
damage to the labyrinth and CB presenting as mixed peripheral and central (CB) patterns
what is oscillopsia
visual disturbance where objects int he visual field appear to jump or blur with head motion -
“when you move the world looks like its bouncing/sliding”
what is VOR
reflex that stabilizes/fixes your vision while your head moves
how do eyes behave in VOR with respect to the head
eyes and head move opposite direction
what is VOR gain
the change in eye angle divided by the change in head angle during a turn - ideally it is 1.0
what happens if VOR Gain does not equal 1
retinal slip (impaired visual acuity) - i.e. there will be oscillopsia
what causes VOR Gain to be >1? <1?
increased eye velocity if >1
increased head velocity if <1
describe the relevance of the VSR
when you reduce the visual and somatosensory input, the VSR will become more active. In other words, the VSR is key for balance
what is the VCR
a reflex that acts in response to vestibular input fromt the neck in order to stabilize the head
T/F: Vestibular issues can cause strong emotional reactions
true - due to the connection of the vestibular system to the ANS, patients may have very strong emotions
what is nystagmus
involuntary eye movement
how is nystagmus named
named for the direction of the fast motion
how does a nystagmus beat
beats towards the unaffected side
A right beat nystagmus means…
the right side is stronger therefore there is a left sided weakness
what is spontaneous nystagmus
a peripheral issue described as primarily horizontal movement with a slight torsional component
how will spontaneous nystagmus change in response to the removal of fixation
spontaneous nystagmus increases when fixation is removed
what is central spontaneous nystagmus (in other words, what do you see in nystagmus that leads you to believe it is central spontaneous until proven otherwise?)
- pure vertical
- pure torsional
- direction changing with fixation
what are the four components of Alexander’s Law?
- nystagmus will beat towards the STRONG side
- nystagmus will INCREASE when gaze is shifted in the direction of the FAST component
- nystagmus will DECREASE when gaze is shifted in the direction of the SLOW component
- nystagmus will be seen MORE with fixation REMOVED
