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Transcript of cvi- Cortical vision impairment webinar-session-1.pdf
Cortical/Cerebral Visual Impairment
Is it one or several or entities?
Can it co-exist with ocular impairments?
SESSION ONE
Barry S. Kran, OD, FAAO
Darick W. Wright, MA, COMS, CLVT
D. Luisa Mayer, PhD. MEd
Webinar Objectives
Increase understanding of the diversity of signs
and symptoms of vision impairment secondary to
pediatric brain damage/maldevelopment
Understand the difference between brain-related
or non-brain related classifications of vision loss
What is What?
“What about a premie with some ROP, but
not blinding, and maybe a little brain injury
but not a devastated brain?”
“Some TVI’s say it is really important for
them to know if a child’s poor vision is due
to the brain or the eye (retina) because
they would teach them differently”
Comment by Pediatric Ophthalmologist
From 24 wks to term, each
cortical neuron establishes
~1000 synaptic connections
– In the last trimester,
several hundred million
synapses are created
every minute!
Wyatt JS. Mechanisms of brain injury in the newborn. Eye (2007)12, 1261-63
http://library.thinkquest.org/C001501/brain/braindevelopment.htm
Accessed 07/09/2010
Brain Development
Preterm brain injury
• Focal & generalized
white matter
abnormalities (PVL) – Impaired cortical folding,
reduced grey and white
matter volumes
– Reduced growth and
development of posterior
corpus callosum and its
connections
http://neonatology.ucsf.edu/specialized-care/cerebral-palsy.aspx
Accessed 9 July 2010
Pediatric Brain Damage and
Visual Impairment
– Cerebral palsy
– Poor gross & fine motor skills
– Poor adaptive functioning
– Lower intelligence quotient
– Behavioral & emotional problems
– Asthma
– Visual pathway abnormalities
(e.g.; ROP, myopia, strabismus)
– Cortical/Cerebral VI
O’Connor AR, Wilson CM, Fielder AR. Ophthalmological Problems associated with premature birth. Eye (2007)21, 1245-60
http://www.nytimes.com/imagepages/2007/08/01/health/adam/
18117Grayandwhitematterofthebrain.html Accessed 11 July 2010
Preterm infants are at risk for:
Pediatric Brain Damage and
Visual Impairment
http://neonatology.ucsf.edu/specialized-care/cerebral-palsy.aspx
Accessed 9 July 2010
Hypoxic ischemic
encephalopathy
(HIE) – Diffuse brain damage
• cerebral cortex,
thalamus and brainstem
– Problems with motor
control, cognition,
emotions, learning
– Cortical/Cerebral VI
Brain injury at Full term is different than injury at Preterm
Pediatric Brain Damage and
Visual Impairment
Primary Visual Pathway
Ocular structures
Optic tracts to the
LGN and on to
the primary
visual cortex http://www.nature.com/nrn/journal/v6/n3/images/nrn1630-f4.jpg
Accessed 11 July 2010
Classification of Vision Loss
• Ocular
– Eye structures, to chiasm
• Ocular motor
– Brain stem, basal ganglia, thalamus,
cerebellum
• Cortical
– Primary pathway (post-chiasm to occipital)
• Cerebral
– Post-occipital, complex brain processing areas
DL Mayer
2.28.10
Ocular
Ocular media, retina,
optic nerve, to chiasm
Cerebral post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
Cortical post-chiasm to V1
(striate or occipital)
Ocular Motor Brain stem,
cerebellum
CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Vision Impairment
Pre-chiasmal visual pathway
Eyes, retina, optic nerves
– Significant uncorrected refractive
error
– Media opacities (ie. cataracts)
– Retinal lesions
– Retinal degeneration/dystrophy
– Optic nerve damage
Chiasm
Ocular Vision Impairment
Diagnostic examples:
– Retinopathy of prematurity* (retinal +)
– Achromatopsia (retinal)
– Leber congenital amaurosis (retinal)
– Albinism (macular hypoplasia and reduced ON fibers crossing at chiasm)
– Optic nerve hypoplasia*
*Brain related visual difficulties may co-occur
DL Mayer
2.28.10
Ocular
Ocular media, retina,
optic nerve, to chiasm
Cerebral post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
Cortical post-chiasm to V1
(striate or occipital)
Ocular Motor Brain stem,
cerebellum
CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Ocular Motor Vision Impairment
May need to be differentiated from visual
field loss, or CVI
Nystagmus
– “Nulling” head-eye positions
– Convergence null
Ocular Motor Apraxia (OMA)
– Lack of horizontal saccades
– Head thrusts to move eyes to target,
overshoot and correction to fixate
Cortical post-chiasm to V1
(striate or occipital)
DL Mayer
2.28.10
Cerebral post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
Ocular
Ocular media, retina,
optic nerve, to chiasm
Ocular Motor Brain stem,
cerebellum
CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Cerebrum
http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cerebrum
http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cortical Visual Impairment
Characteristics • Post chiasmal to occipital lobe damage
– Light gazing or withdrawal
– Better visual attention for: • Moving vs. static objects
• Familiar vs. novel objects
• Simple vs. complex environments
– Difficulty integrating gaze with reach
– Difficulty integrating looking with listening
– Poor social gaze
– Delayed visual (& other) responses
• Dr. Christine Roman-Lantzy
DL Mayer
2.28.10
Cerebral post-V1
(parietal, temporal lobes,
motor cortices & frontal lobes)
Cortical post-chiasm to V1
(striate or occipital)
Ocular Ocular media, retina,
optic nerve, to chiasm
Ocular Motor Brain stem,
cerebellum
CLASSIFICATION OF
VISUAL IMPAIRMENT
BY CAUSE
Cerebrum
http://www.hermes-press.com/altstates.htm Accessed 07/13/2010
Cerebral Visual Impairment
Characteristics
• Post occipital lobe brain damage
– Complex brain processing difficulties
– Dorsal/ventral stream dysfunctions
• Prof. Gordon Dutton
• Dr. August Colenbrander calls “Cognitive
dysfunction”
Dorsal & Ventral “pathways”
Ventral Stream – “What is it?”
Recognition of objects
Occipital lobes – Receive visual input (primary visual pathway)
Temporal lobes – input from occipital lobes
– Visual “library”
– Words, numbers, shapes, landmarks
– Faces
– Color
Ventral Stream
Occipital Lobe
Temporal Lobe
Apple!
????
Dorsal Stream
Occipital Lobe
Posterior Parietal
Motor Cortex
Frontal Cortex
Dorsal stream -“Where is it?”
Vision for action - visual attention,
visually guided movement
• Occipital - posterior parietal lobes – Integration of sensory input with attention and
during motor output, management of visual
complexity
• Feedback from frontal cortices – Motor planning, head/eye movement, visual
guidance of movement
I want it
Attend, Attend
Fixate with
Eyes
Reach
Apple!
I want it
It’s in front of me Reach with
right hand
?????
Too Much
Information!
!!!!!!!! Where do I
look???
How do I move?
G N Dutton 2012
Summary
• Brain damage that occurs pre-term is
different than damage that occurs with full-
term babies.
• Vision Loss can be classified based on
location within the brain and visual pathway
as: – Ocular
– Ocular Motor
– Cortical
– Cerebral
Summary
Visual Sequelae of Pediatric Brain Damage
A complex combination of abnormal visual
behaviors due to brain damage, with
probable subcategories that CAN co-exist
with ocular & ocular-motor categories.
Summary
• Historically, many have defined Cortical
Vision Impairment as being associated only
with the visual pathway and occipital lobe.
• Cerebral Vision Impairment involves other
portions of the brain that are required for
visual function. – Dr. Gordon Dutton’s - impact of damage to the Dorsal and Ventral
Streams on visual function.
Images & Resources
About Brain Injury www.waiting.com/brainanatomy.html#anchor2884157 Brain Injury Association - http://www.biasd.com/en_brain_map.html Wikipedia - http://en.wikipedia.org/wiki/Brain Dennison E, Hall Lueck A eds. Proceedings Summit on Cerebral/Cortical Visual Impairment April 30, 2005 2006 AFB Press NY, NY Dutton GN, Bax M, editors. Clinics in developmental medicine no. 186: visual impairment in children due to damage to the brain. London: Mac Keith Press; 2010 Hoyt CS. Visual function in the brain-damaged child. Eye. 2003;17:369–84. Kran BS, Mayer DL. Chapter 14 Vision impairment and brain damage in Taub, Bartuccio, Maino eds Visual diagnosis and care of the patient with special needs. Lippincott 2012 Lueck, A (2010) Cortical or Cerebral Visual Impairment in Children: A Brief Overview. JVIB, AFB press. Roman-Lantzy C. Cortical Visual Impairment: An approach to assessment and intervention 2007 AFB Press NY, NY
Cortical/Cerebral Visual Impairment
Is it one or several entities?
Can it co-exist with ocular impairments?
Barry S. Kran, OD, FAAO
Darick W. Wright, MA, COMS, CLVT
D. Luisa Mayer, PhD. MEd