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2024 Clinical test of balance
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Clinical tests of vestibular function I -
Eye movement assessments and VOR
Paul Radomskij BSc MSc
Overview
Objectives of Bedside Tests
Are there any central signs that might explain the patient’s symptoms?
Are there any central signs that mig...
Are there any peripheral signs that might explain the patient’s symptoms?
Are there any peripheral signs th...
Are there problems with vision, vestibular, proprioceptive systems?
Are there problems with vision, vestibul...
Presence of vestibular nystagmus?
Presence of vestibular nystagmus?
Helping you to decide on which further tests required
Helping you to decide on which furth...
What is nystagmus?
Definition of nystagmus
Greek word ‘drowsy’
Rapid involuntary movement of the eye
Nystagmenos
After taking your history
Clinical / bedside tests
- testing for tropias and phorias
- testing smooth pursuit, saccadic, gaze and vestibuar induced eye movements
- testing functional balance (the next presentation will cover this)
Looking for Tropias
Cover-Uncover
Eyes do not appear in alignment – maybe le...
Eyes do not appear in alignment – maybe left eye looking slightly outwards or inwards
1. Patient looks at fixation object
2. Cover one eye (e.g left) for a few seconds - what does the other (right) eye do? Any movement?
3. Uncover the eye (left)
4. Watch right eye as left is uncovered. Any movment?
5. Repeat for other eye
If right eye dominant / left eye weak, what could we expect?
If right eye dominant / left eye weak, wh...
Cover/ Uncover Left Eye
We might expect the following:
As cover left eye, no movement of right eye
As uncover left eye, still no movement of right eye
Cover/ Uncover Left Eye
Cover/ Uncover Right Eye
As cover right eye, movement of left eye inwards (for example)
As uncover right eye, movement of left eye outwards
This would be termed left exotropia (eyes always deviated)
Different types of tropia
If left eye had deviated inwards (after uncovering the other eye) it would be esotropia
If left eye had deviated upwards it would be hypertropia
If left eye had deviated downwards it would be hypotropia
Alternate Cover test
Cross-cover
Looking for Phorias
Cover - uncvover test first
Eyes look in alignment
Cover – uncover test completed
No tropia detected
Eyes are steady Eddie - no brealing of fusion
.
Next step alternate (cross) cover test
Looking for phorias (eyes sometimes deviated)
Cross-cover test
Cover right eye – look at left
Uncover right eye and immediately cover left eye – now look at right eye
By breaking fusion it can tease out the problem
Much harder to say whether it is left or right problem as both left and right eye will move if there is a phoria
Looking carefully may help
Demonstration cross cover
Smooth Pursuit test
Smooth pursuit
Simple test – using pen or tips of finger
Looking for saccadic intrusion; cog-wheels etc
Most abnormalities detected will have a central cause
Instructions
The patient should be instructed to keep their head as still as possible, and to follow the moving target with their eyes, as accurately as possible, immediately when it moves.
Conduct test at amplitudes of 15 to 30 degrees
Conduct test at frequencies between 0.1 Hz and up to 0.7 Hz
Demo -Smooth Pursuit
Demo - Horizontal and vertical Pursuit
Demo - Horizontal and vertic...
Checking for abnormlities
Checking for abnormlities
Bi-directional? Vertical? Horizontal?
Affected by drugs, age and tiredness (will usually affect both directions
Affected by central pathology (unilateral will tend to be central cause - that's why imprtant to chek for squints)
More on this later in the year!
Saccades
Saccades
The Basics
Again use a pen top / finger
Looking for speed, over-shooting ( ???-metria), under-shooting (???-metria)
Any delays in initiating saccades
Instructions
The patient should be instructed to keep their head as still as possible, and to look quickly to the target (e.g. raised finger / pen top) as accurately as possible
Conduct test at amplitudes of 15 to 30 degrees. Randomised.
No guessing - patients sometimes mmove eyes before target presented
Demo -Saccades
Demo - Horizontal and vertical saccades
Demo - Horizontal and vertic...
Checking for abnormlities
Checking for abnormlities
Affected by central pathology
Disconjugate
Delayed
Slow
Under / over shooting
More on this later in the year!
Tests for Convergence and SN
Eyes moving together?
Any nystagmus present?
Tests for Convergence and SN
Instructions
Look at target left 30, right 30 degrees and up and down
Check for nystagmus
Check for nystagmus without fixation using Frenzel galsses
Gaze tests
OKN test
Use small drum or ipad
OKN test
Demo - "OKN" test
Cerebellar Function tests
Arms outstetched - pushed down
Hand tapping
Finger - nose
Inability to do these tasks linked to cerbellar abnormalities
Demo - cerebellar test
The vestibulo-gram - testing the VOR
The vestibulo-gram - testing t...
Slow VOR & Head thrust test
Test slow VOR by small movements
Test for chronic peripheral vestibular loss
First described by Halmagyi and Curthoys in 1988
Looking for ‘catch-up’ saccades
Can immediately follow head-eye movement test
Demonstration - head thrust
Demonstration Slow VOR & Head Thrust
Results
Corrective saccade on side of problem
Good specificity
Poorer sensitivity - patient may have a problem but negative head thrust
Office chair test
10 turns approx 1 revolution every 2 seconds
Observe post-rotation nystagmus with frenzel glasses
Measure time it takes for resulting nystagmus to disappear
Repeat opposite direction
< 10 secs duration possible vestibular dysfunction
Demonstration
VORS
VORS
Move chair whilst patient looking at thumb
Nystagmus should be supressed
If not, then it is a central sign
Demo -VOR cancellation
Demo -VOR cancellation
Dynamic visual acuity
Use of Logmar Chart / Landolt rings
Left to right movement 2 Hz +/- 10 degrees
How many lines lost?
Three or more – problem with VOR (Bilateral failure)
Demo - DVA
NO.....
NO.....
Paediatrics
Landolt rings
Head shaking test
20 head shakes (active or passive)
Use digiatl metronome if necessary
Head tilted fwds 30 degs (? - discuss)
No visual fixation
Observe with Frenzel glasses (or record) for 30s
If nystagmus – pathological at least three beats (initial direction away from weaker side e.g. left beats - right sided problem)