Finally Exam vHIT,HINTS, Flashcards
VOR
If you accelerate your head to the left which way do the eyes and endolymph go?
head left
Endolyph & Eyes right
Describe the image for vHIT
Green: Head is at rest - being held into place = no movement
Purple: The head is thrust rapidly, - you are seeing an equal and opposite reaction at a large magnitude - since this is during teh head thrust
#3 : Immediate/abrupt stop of head
Pink: after you stop you will continue to see and equal and opposite reaction on a lower magnitude and will continue to decraese until it levels out since head is at rest once again.
What are the three phases of vHIT?
- head impulse starts (head exceeds 20 deg/sec)
- Peak Velocity or Acceleration (A/V meet max value)
- Head Impulse end (Stop 0 deg/sec) & rebound is seen
____ bedside screening test that can detect semicircular canal dysfunction in all canals, useful for detection of peripheral vestibulopathy
Head Impulse Test is a bedside screening test that can detect semicircular canal dysfunction in all canals, useful for detection of peripheral vestibulopathy
Head Impulse Test is a bedside screening test that can detect what?
Head Impulse Test is a bedside screening test that can detect semicircular canal dysfunction in all canals, useful for detection of peripheral vestibulopathy
HIT detects ____ dysfunction in ____ . Detects ____
HIT detects SCC dysfunction in all canals. Detects peripheral vestibulopathy
What is a abnormal finding for vHIT?
Altered VOR gain and presence of re-fixation or catch-up saccades in abnormal individuals during head thrust
Reduced gain = BVL
Overt & covert = Uncompendated UVL
Covert = Compensated UVL
All peripheral
True or False
Re-fixation saccades occur in those with normal VOR
FALSE
Re-fixation saccades occur in those with abnormal VOR
Covert - occur during head movements (cannot see with our naked eyes)
Overt - occur after head movement (can see with our naked eyes)
Saccades that occur during the head movement & difficult to see with eye
Covert
Saccades that occur after the head movement & seen with the naked eye
Overt
Covert Saccades
Saccades that occur during the head movement; difficult to impossible to see with the naked eye
Overt Saccades
Saccades that occur after the head movement; can be seen with the naked eye
- present when UVL is uncompensated
How to preform vHIT
- patient focuses on fixed point
- Move head fast (200+ deg/sec) 10-20 deg range only
- The key is the quickness, you do not have to go far, just fast.
- Unpredictable movements
- Can do on patients down to 10 mo. old.
Youngest you can do vHIT
10 mos
What are the two things analyzed with vHIT data?
Gain = eye movement relative to head movement
Normative >0.7 some systems, >0.8 other systems
Presence of re-fixation saccades (overt and covert)
vHIT is typically performed in at least ___ plane but can also do ___ and ___
Typically performed in at least horizontal plane but can also do LARP and RALP
Occur during head movement
Compensated lesion
Covert
Occur after head movement
Uncompensated lesion
Overt
What all does vHIT measure?
Gain/VOR gain
Presence of Saccades
Measures each canal separately.
Normative Gain for vHIT
Normative greater or equal to 0.7 some systems,
vHIT Clinical use benefits
- Functional Measure
- Eval High Frequencies
- High Sensitivity to Vestibulopathy
- Canal specific info
- Track VRT Progess & Compensation
vHIT limitations
- Only HF (miss LF vestib deficits)
- Not sensitive to dysfunction 2nd to Mernieres
- Technique challenging
vHIT
Normal or Abnormal & why?
Normal, no overt or covert saccades and gain is normal
vHIT
Normal or Abnormal & why?
Abnormal Unilateral vestibular loss, uncompensated
* Right vhit normal
* Left vHIT shows both covert and overt saccades – left sided UVL
vHIT
Normal or Abnormal & why?
Abnormal Bilateral VL
* covert saccdes are seen in both left & right
* Eye have no gain then saccdes
Normal or Abnormal & why?
vhit
Normal or Abnormal & why?
vhit
Normal or Abnormal & why?
vHIT VS Calorics
- Calorics are highly variable
- Calorics can be affected by alertness and medications
- Calorics are unpleasant
- Calorics are time consuming
- Calorics only tell you HSCC function
- Calorics are not portable and require dark environment
- Calorics reimbursed – vHIT is not
- vHIT miss milder UW & less sensitive than C
- vHIT grester specificity
- They are sensitive to different conditions
Caloric Disadvantages comapred to vHIT for angular VOR
- Too LF un realistic
- only HSCC
- Calorics induce a non-physiologic endolymph flow in the horizontal SCC due to temp gradient
- time consuming
- discomfort
- do not supply compensatory info
stand for
HINTS
H.I : Head Impulse
N: Nystagmus
T.S: Time skew
What is HINTS used for?
HINTS is used to be able to distinguish between Strokes & benign acute vestibulopathies by using bed side oculomotor tests
HINTS is used to be able to distinguish between ____ & ______ by using bed side oculomotor tests
HINTS is used to be able to distinguish between Strokes & benign acute vestibulopathies by using bed side oculomotor tests
HINTS pros
More sensitive (<24 hours) and less costly than early stage MRI for stroke
HINTS Cons
Requires expertise not routinely available in E.R.
HINTS is similar to what?
Conceptually similar to ECG to diagnose acute cardiac ischemia
HINTS
Head Impulse abnormalities is indicative of what?
Peripheral Test
Nystagmus is indicative of what?
Subjective interpretation
(peripheral, or central)
Test of Skew abnormalities is indicative of what?
Central
How to test skew deviation
- have patient look at nose
- cover one eye and then fastly uncover it again.
- Observe is the eyes need to move to re-align - movement = positive test (abnormal) = central
- Do for both eyes
Peripheral or Central
Onset: Only Sudden
Severity: Intense
Pattern: Intermittent
Worse w/movement: Yes
Nausea: Frequent
Nystagmus: Horizontal
Fatigue: Yes
HL/Tinnitus: May occur
CNS signs: NO
Peripheral
Peripheral or Central
Onset: Only Sudden
Peripheral
Peripheral or Central
Nystagmus: Horizontal
Peripheral
Peripheral or Central
Severity: Intense
Peripheral
Peripheral or Central
Pattern: Intermittent
Peripheral
Peripheral or Central
Worse w/movement: Yes
Peripheral
Peripheral or Central
Nausea: Frequent
Peripheral
Peripheral or Central
Fatigue: Yes
Peripheral
Peripheral or Central
HL/Tinnitus: May occur
Peripheral
Central or Peripheral
CNS signs: NO
Peripheral
Central or Peripheral
Onset: Sudden or gradual
Severity: Less Intense
Pattern: Constant
Worse w/movement: Variable
Nausea: Variable
Nystagmus: Vertical or multi directional
Fatigue: No
HL/Tinnitus: No
CNS signs: Usually
Central
Central or Peripheral
Onset: Sudden or gradual
Central
Central or Peripheral
Severity: Less Intense
Central
Central or Peripheral
Pattern: Constant
Central
Central or Peripheral
Worse w/movement: Variable
Central
Central or Peripheral
Nausea: Variable
Central
Central or Peripheral
Nystagmus: Vertical or multi directional
Central
Central or Peripheral
Fatigue: No
Central
Central or Peripheral
HL/Tinnitus: No
Central
Central or Peripheral
CNS signs: Usually
Central
What is SHIMP
- variant VHIT test where patients were asked to view a laser dot that moved with their head.
- Turn off VOR instead of using it
- “anticompensatory” saccades = normal controls, but less commonly found who have less VOR to suppress.
Codes for vHIT
Currently, as of 2020, no CMS approved codes for vHIT testing
____ a type of TBI caused by a bump, blow, to the head or by a hit to the body that causes the head and brain to move rapidly back and forth.
* This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in the brain and sometimes stretching and damaging brain cells.
Concussion
Concussion signs frequently do not appear on _____
Concussion signs frequently do not appear on CT or MRI
What vestib test is sensitive to concussions?
oculomotor is sensitive of this.
How to diagnosis concussions
There is no standard diagnostic test
* currently based on group of symptoms or signs
* present immediatly or over one or many weeks after (some no symptoms at all)
