Week 5.7 Vestibular DD Exam Flashcards
what must you always assess first
oculomotor exam
what are tests for peripheral dysfunction
spontaneous nystagmus gaze-evoked nystagmus head shaking nystagmus head thrust dynamic visual acuity Dix- hallpike valsalva
what are test for central dysfunction
spontaneous nystagmus smooth pursuit saccadic eye movements vergence dynamic visual acuity VOR cancellation
what is the difference between visual fixation and fixation removed
visual fixation: you do things in ambient light, and the patient has to fixate
fixation removed is when they don’t fixate, so you use something like a fresnel lens or goggles.
when testing nystagmus, do you use natural light or goggles
goggles
when doing the Dix hall pike, goggles or ambient light
goggles
when doing the VOR cancellation and DVA ambient or goggles
ambient light
what do you look for when testing nystagmus
you are looking of the abnormal beating, and what kind of fast and slow beating there is
what happens if nystagmus is observed in ambient light (with abnormal smooth pursuit, saccadic eye movements and abnormal VOR cancellation)
they may have a known neurologic condition, like a stroke or TBI, to they have a central vestibular dysfunction that needs to be referred out
what is the likely cause of nystagmus is observed with goggles
may have an acute peripheral hypo function or they have something central going on.
what are you looking for when you are testing smooth pursuit and convergence
you are looking for whether or not it is bumpy, and if they eyes can actually come together to look at the nose and when they get double vision
what happens if there is abnormal smooth pursuit
saccadic intrusions and not smooth movement.
what happens if there is abnormal convergence
double Vision at greater than 3-4 inches away from the nose
what happens if there is anything abnormal with smooth pursuit or convergence
a central issue
how do you test saccadic eye movements
you hold the patients head, and ask them to look between two targets. check if they are hitting the target or over or under shooting, or need many tried to actually get there
what is normal and abnormal saccadic movements of the eyes
what diagnosis
normal: hits the target with 1-2 movements and vert minimal symptoms
abnormal: multiple movements to reach the target, and over and undershooting the target.
central issues
how do you test VOR
have the patient extend their arm, watch their thumb, and rotate their head and arm at the same time while watching the target
what is VOR cancellation
VOR is the ability to move the eyes equal and opposite to a head motion, and keep the image stable on the retina. So when you cancel it out, you want everything to move together
what is abnormal VOR cancellation and what might it mean
there is central dysfunction
the eyes can’t stay on the target, or they get dizzy
what is gaze evoked nystagmus.
with goggles, you ask the patients to move the eyes in all directions, and look for nystagmus when they hold each position.
TF: always go to end range when testing gaze evoked nystagmus
false, don’t
how does nystagmus from a peripheral lesion look
direction FIXED nystagmus, the eyes beat in the same direction, no matter which way the patient looks
what does nystagmus from a central lesion look like
the direction is changing nystagmus. like the eyes might beat up when looking up, but beat down when looking down
how do you test head shaking nystagmus
have them close their eyes, have goggles on, 30 degrees cervical flexion, rotate their head 20 times, look at them after 20 and observe nystagmus.
what is a positive head shaking nystagmus test
the nystagmus will beat toward the intact side, and the fast phase is towards the intact side. SO THE CONTRALATERAL SIDE HAS THE HYPO-FUNCTION
a positive head shaking nystagmus usually coincides with…
positive head thrust test and a history of unilateral hypo function
how do you do a head thrust test
fixate the patients eyes on a target like your nose, and hold in 30 degrees cervical flexion, and quickly rotate them 30 degrees. with eyes on target in random order.
how do you interpret a head thrust test
there is a positive test when there is a delay in returning the the target, and the delay occurs on the impaired side
what does a positive head thrust test mean it could be
unilateral or bilateral peripheral hypo function
`what is a dynamic visual acuity test
read lowest line you can, move their head at 120 beats/min as they continue to read from the top to the bottom, and not the difference in which line they can read
what does the DVA test
the VOR
what is considered normal and abnormal for DVA
normal is 2 lines or less
abnormal is 3 lines or more
what can an abnormal DVA mean
peripheral hypo function
central dysfunction
decreased VOR
