BVP - Clinical Management of Oculomotility Dysfunction in Children - Week 9 Flashcards
Is the optokinetic nystagmus reflex slow or quick? Is it conjugate? When does it occur?
Slow, conjugate
When looking at objects passing across our field
What is the vestibulo-ocular reflex? Is it slow or quick? Is it conjugate?
Stabilises image on the retina when the head moves
Slow, conjugate
List four voluntary types of eye movements. Note if they are fast or slow, and if they are conjugate.
Fixation - inhibition of movement
Saccades
-fast, conjugate
Pursuit
-slow, conjugate
Vergence
-slow, disjunctive
What four extraocular muscles are supplied by CN3?
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
What extraocular muscle is supplied by CN6?
Lateral rectus
What extraocular muscle is supplied by CN4?
Superior oblique
List the primary action for each extraocular muscle.
Superior rectus - adduction
Inferior rectus - abduction
Medial rectus - up
Lateral rectus - down
Superior oblique - intorsion
Inferior oblique - extorsion
List the secondary actions (2) for four of the extraocular muscles.
Superior rectus - intorsion, adduction
Inferior rectus - extorsion, adduction
Superior oblique - down, abduction
Inferior oblique - up, abduction
Is the OKN reflex an advanced or primitive eye movement response?
Primitive
Concerning the OKN reflex in infants, what can be said of the symmetry between temporal-nasal response vs the nasal-temporal movement? What happens around 6 months of age? How does this relate to strabismus/amblyopia? Explain.
Temporal-nasal response greater than nasal-temporal movement
Becomes more symmetrical by 6 months
Strabismus/amblyopia delay this semmetry - possible to use this difference to screen?
Is the VOR advanced or primitive?
Primitive
Concerning VOR, what direction do the eyes move relative to the head’s movement?
Opposite
Concerning VOR, do infants have higher or lower gain compared to adults? What does this do? What happens to the gain with age? Why?
Have a higher gain - stabilises the image to ensure development of optimal acuity
Gain reduces with age as the other reflex systems sevelop to augment gaze
what are saccades like in infants vs adults (2)? What is the latency like in infants vs adults? What evolutionary purpose may this have? When is it thought to be developed by (age)?
Infant saccades are variable and inaccurate compared to adults
Latency higher in infants - 800ms infants vs 200ms adults
Made in response to maintain fixation of the mother
Developed by 6 to 12 months
List four subtypes of saccades.
Prosaccades
Regressive saccades
Antisaccades
Reflex saccades
What types of saccades do infants rely mor on to track vs smooth pursuit (note: not saccade subtypes)? What happens with age?
Depend on small saccades rather than smooth pursuit
With age, small saccades decrease and smooth tracking increases in between saccades
Are saccades attention dependent?
Yes
Is the devlopment of smooth pursuit in children symmetrical? Explain, giving age when mature (2).
Asymmetrical
Horizontal pursuit is mature by age 7
Vertical pursuit is mature by age 11
What aspect of oculomotor control us fully developed at birth? What happens following birth? What happens by age 1?
Virtually no aspect of oculomotor control is fully developed at birth but quickly develops following birth
Is close to adult levels at age 1
List four factors that limit oculomotor performance in neonates.
Attention
Motivation level of alertness
Distracton
Fatigue
What three things can the development of eye movements be affected by?
Stress/fatigue
Environmental factors
Genetic factors
Does oculomotor control develop slowly or quickly in children during primary school years? Is it fully developed when they start school?
Slowly
Not fully developed when they start
What cellular pathway controls smooth pursuit? What else does it control? Keeping this in mind, what do smooth pursuit skills reflect?
Magnocellular pathway
Also controls focal visual attention
Smooth pursuit skills reflect attention capability
In which two lobes of the brain saccades initiated? What are saccades influenced by?
Frontal and parietal
Influenced by attention
Are oculomotility dysfunctions associated with learning problems?
Yes
List 8 symptoms of an oculomotility dysfunction.
Moving head excessively when reading
Skipping lines when reading
Omitting or transposing words when reading
Losing place when reading
Requiring a finger or marker to keep place
Experiencing confusion during the return sweep phase of reading
Experience illusory text movement
Having deficit ball-playing skills
What percentage of children with a learning difficulty also have an oculomotor dysfunction?
Up to 96%
What do studies suggest of the incidence of accommodation deficits in children with developmental dyslexia? What about oculomotor tracking and vergence deficits?
Higher incidence of all three in dyslelxic children vs those without
Slow reading in school-age children with anisometropic amblyopia is related to what (2)?
Increased frequency of saccades
Fixation instability of the fellow eye
Consider the relationship between dyslexia and increased incidence of ocular disturbances (and its impact on reading), do studies suggest there is improvement after therapy/treatment/refractive correction, or is it negligible?
78% showed an improvement
What is binocular coordination like in dyslexic children during and after saccadic eye movement? What does this imply?
poor binocular coordination
-implies they have an oculomotor deficiency
In comparison with age-matched control readers, what three features do dyslexic readers’ eye movements have when reading words, pseudowords, and sentences?
Longer fixations
Shorter saccades
More regressions
What is thought to cause reading difficulties in dexlexia? Emerging evidence suggests that this arises from what? What stream specifically?
Phonological deficits
-how words are sounded out
Emerging evidence suggests phonological problems and reading impairment both arise from poor visual coding
-attention mechanisms controlled by the dorsal visual stream
Describe how observation can be used to evaluate eye movements (2)?
Use HH test
-check smooth pursuit, saccades
What is meant by NSUCO/SCCO testing?
HH test for smooth pursuit/saccades, but is quantitative and rated
What is the king devick test?
Reading eye movement test
What is the DEM test?
Looks at reading eye movements only
How should the HH test for qualitative observation ideally be done (2)?
Do not give specific instructions, just ask them to watch the moving target and follow it as it moves
-observe and document
If they move their head, document and repeat the test, asking to use just their eyes, then document
What test uses wolff wands and what are they?
NSUCO two rods held in a V shape, to test saccades and pursuits
What is the king devick saccadic fixation test designed to stimulate? Is it timed or untimed? Are errors recorded? Does it take into account the child’s rapid automatic naming skills?
Designed to stimulate normal reading process
Timed test and errors recorded
Doesnt take into account childs rapid automatic naming skills
Describe the king devick test.
3 test cards of increasing difficulty
Patient must read them out loud quickly without using fingers to guide them
Time is taken and number of errors
What is the DEM test designed to stimulate and does it take into account the child’s rapid automatic naming skills?
Designed to stimulate reading eye movements
Does take into account the child’s rapid automatic naming skills
Describe the DEM test. Is it reliable and repeatable?
Test cards check vertical naming speed with horizontal reading eye movement speed
Repeatable and reliable
Does the DEM test correlate with saccadic eye movement skills or symptomatology?
No
What is the DEM test related to (2)?
Reading performance and visual processing speed
What do studies conclude of poor readers’ horizontal scanning and what is this related to? What is the recommendation
poor readers showed poor horizontal scanning when assessed with DEM and this was related to slow reading speed
-DEM should be used by optometrists as a screening tool to idenfity poor reading in school children
Do studies suggest that low DEM is a cause of poor reading or an effect? Why?
Low DEM is an effect of poor reading, not a cause
-DEM measures reading eye movements that are dependent on proficiency of reading
Is DEM a reliable measure of saccadic eye movement function? Can it be used in isolation?
Not reliable for saccades
Not to be used in isolation
What are three treatment options for oculomotor dysfunction? Explain why each is an option.
Refractive correction - will have a spinoff effect on improving eye movement
Near add - impacts on visual efficiency and therefore performance, including eye movement skills
Vision therapy
-address any accommodation/vergence problems
-address any oculomotor deficiencies
-consider other factors first before starting VT
What 5 other factors should you consider before starting vision therapy for treatment?
Neurological involvement
Poor muscle tone
Dyspraxia
Gross motor problems
Fine motor problems
Who can you refer to for an assessment before you beign vision therapy?
Occupational therapist
Can accommodative and vergence therapy alone have the potential to improve reading speed and reading eye movements? Explain.
Yes
Additional VT can be given for accommodative and saccadic function
Can vision therapy be applied to oculomotor dysfunctions in acquired brain injury?
Yesd
List 8 vision therapy activites for developing oculomotor skills.
Saccadic pyramid fixations
Rapid fixations - find the word
Smooth pursuit activities - mazes
Computer tracking activities
Pie tin rotations - smooth pursuit
Letter/number tracking sheets
Marsden ball games
torch chases
