the visual consequences of when a mild concussion becomes ... · the visual consequences of when a...

The Visual Consequences of when a Mild Concussion becomes a Severe Brain Injury…

Dan L. Fortenbacher, O.D., FCOVD

Lindsey Stull, O.D., FCOVD

Ryan Edwards, O.D. MVTSG 2014 – MCO

January 25, 2014

…an Advanced Model for Neuro-Optometric

Vision Rehabilitative Care

Drs. Fortenbacher, Stull, Edwards - MVTSG

2014 MCO

• Why? – Because too many patients who have a “mild concussion”

exacerbate into a more severe brain injury, resulting in severe visual problems, often weeks and months after the injury

• What? – We will attempt to remove some of the mystery surrounding

acquired brain injury (ABI) and show how even a “mild concussive event” can lead to serious vision problems

• How? – Show how you can apply the principals of this advanced model for

effective neuro-optometric vision rehabilitative treatment in your patient care


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According to the US Centers for

Disease Control and Prevention

• Mild traumatic brain injury (mTBI) is:

…”the occurrence of injury to the head arising from blunt trauma or acceleration or deceleration forces with one or more of the following conditions attributable to the injury: any period of observed or self –reported transient confusion, disorientation or impaired consciousness, dysfunction of memory around the time of injury, or loss of consciousness lasting less than 30 minutes.”


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mTBI continued

• …“In addition, observed signs of injury to

the head, irritability, lethargy, or vomiting

following head injury, especially among

infants and very young children;

headaches, dizziness, irritability fatigue or

poor concentration, especially among older

children and adults”


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CDC 2003 Report to

Congress

• Of the more than 1.5 million people

experiencing TBI each year in the United

States, it has been estimated that 75%

experience mTBI


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http://www.cdc.gov/ncipc/pub-res/mtbi/mtbireport.pdf

http://www.cdc.gov/ncipc/pub-res/mtbi/mtbireport.pdf

Unified approach to managing

mTBIs

• Department of Defense and Department of Veterans Affairs

• Majority of TBIs in military and civilian population are considered mild

• “Mild” shouldn’t be used to define the severity of symptoms

• www.ncbi.nlm.nih.gov/pmc/articles/PMC3021720 Drs. Fortenbacher, Stull, Edwards - MVTSG

2014 MCO

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3021720

Diagnosing with Imaging

• Common feature of mTBI is Diffuse Axonal Injury (DAI)

• Symptoms are primary tool for diagnosis of mTBI because:

• CT scans often normal

with mTBI patients

and poor at detecting DAI


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MRI

• DAI is difficult to detect

using conventional MRI


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Advancements in Imaging

• Goal is create a unified approach to diagnose mTBI

• MRI technique called Diffusion Tensor Imaging (DTI)

• Detects microscopic brain matter tract lesions

• Measures Fractional Anisotropy (FA)- flow of water molecules along axons in brain


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Fractional anisotropy (FA) readings that were

detected using diffusion tensor imaging.


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Interpretation of Low FA

• Low FA represents disorganized movement of water molecules

• More disruption indicates more severe injury and more symptomatic

• High correlation between low FA and impaired executive function testing*

http://www.ncbi.nlm.nih.gov/pubmed/19567646

* Lipton, et al. Diffusion-Tensor Imaging Implicates Prefrontal Axonal Injury in Executive Function Impairment Following Very Mild Traumatic Brain Injury. Radiology 2009; 252: 816-824


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http://www.ncbi.nlm.nih.gov/pubmed/19567646

Interpretation of High FA

• High FA indicates more organization and

therefore may represent less injury or brain

is already trying to compensate for injury


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Conclusions

• An increase in the FA value may represent

a measurement of neuroplasticity and

improvement in brain organization

• FA values may give rehabilitation team a

marker to show progress and determine if

patient is responding well to treatment


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“Post Trauma Vision Syndrome is the

most common visual sequel to mTBI.” 1998 Study guide: brain injury rehabilitation, pain rehabilitation, Supplement to

Archives of Physical Medicine and Rehabilitation, 79(3)(Supple.1), S10-S14


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Post Trauma Vision Syndrome

Characteristics

• Convergence insufficiency

• Exotropia or high exophoria

• Defective stereopsis

• Accommodative dysfunction

• Oculomotor dysfunction

• Low blink rate

• Spatial disorientation


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Post Trauma Vision Syndrome

Symptoms

• Diplopia

• Dizziness

• Headaches especially with visually demanding tasks

• Light sensitivity

• Difficulty reading

• Skipping, repeating lines when reading

• Blurred vision especially at near

• Poor spatial judgment and depth perception

• Poor concentration and attention

• Poor balance, coordination, posture

• Poor visual memory


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William Padula, O.D.

• Hypothesize that PTVS is due to shearing

injury particularly at the midbrain level

where the superior colliculi integrates and

organizes visual spatial information

• Disruption between focal and ambient

visual system


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Neural Substrates of Vision


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Four Anatomical

Components

• Cerebral Hemispheres

• Diencephalon

• Brainstem

• Cerebellum


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Cerebral Hemispheres (2)

• Four Lobes


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Frontal Lobe

• Most complex

• Last area of the brain to

mylenate

• Not a single functional unit


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Frontal Lobe – 3 major

divisions

• Precentral area

• Premotor area

• Prefrontal area


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Precentral and Premotor

• Work as a unit or team

• Planning and carrying out motor behavior

• Including saccadic eye movement


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Prefrontal area

• Cognitive sophisticated integrative system

• Highest level of visual and other sensory modality

processing

• Results in higher action planning

• Incorporate meaning and intention


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3 subdivisions of Prefrontal

• Dorsolateral

– Working memory

– Executive functioning

• Orbital frontal

– Personality

– Self Control

• Medial frontal

– Motivation for goal oriented activities Drs. Fortenbacher, Stull, Edwards - MVTSG

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Prefrontal Lobe


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Books on the Frontal Lobe


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Books on Frontal Lobe


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Temporal Lobe

• Object recognition

• Memory acquisition

• Emotional Variance


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Parietal Lobe

• Processing motion and location

• Multisensory integration


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Occipital

• Reception and early visual processing

• V1, V2 – Depth perception

• V3,V4,V5 – motion detection, size and

color

• V6- unknown

• V8 – Color analysis


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Diencephalon


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Pulivinar


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Diencephalon

• Thalamus – Pulvinar

• Integration of somatosensory and visual information

• Visual feature discrimination

• Analysis of vision

– Lateral Geniculate Nucleus – LGN • Part of afferent visual system

• Higher order visual processing at an early stage

• Hypothalamus – circadian rhythms and under control of the amygdala and prefrontal cortex


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Brainstem

• Diverse collection of nuclei related to

altering-arousal system that helps mediate

attention


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Cerebellum

• Spatial organization and memory

• Refining motor control and motor learning

• Vestibular input for balance and spatial

orientation

• Some cognitive functions


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The 2 visual processing streams

of the brain


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Two major visual processing

streams

• Ventral stream

– Connection to the temporal lobe

– Object recognition

• Dorsal stream

– Connection to the parietal lobe

– Spatial concepts


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Dorsal Stream splits into 3 pathways at

Posterior Parietal Cortex

• Parieto-prefrontal pathway

• Parieto-premotor pathway

• Parieto-medial temporal pathway


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Each pathway of the PPC controls

different elements of visuo-spatial

function

• Neural nexus of visuo-spatial processing

and intermodal processing

• receives input from

– the auditory cortex

– vestibular input

– other areas of the brain


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Parieto-prefrontal pathway

• Eye movements important for reading

• Spatial working memory

– Important for navigating through new

environment


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Parieto-premotor pathway

• Has projections to both dorsal and ventral

premotor cortex

• Receives vestibular input from cerebellum


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Parieto-premotor pathway

• Visually guided action

• Navagation

• Integration of body movement and vision


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Parieto-medial temporal pathway

• Connections to limbic areas

• Crucial for navigation

• Most complex, least understood


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Pre-Frontal Cortex –The Conductor

• Eye movements

• Visual attention

• Working memory

• Goal directed behavior Drs. Fortenbacher, Stull, Edwards - MVTSG

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Effects of mTBI on Prefrontal Cortex

• Oculomotor Dysfunction

– Deficiency in Saccadic Eye movement

• Vergence disorders

• Poor Visual Attention

• Trouble Interpreting visual space

• Poor working memory


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Effects of mTBI on PPC

• Dizziness, loss of balance

• Poor intersensory/intermodal integration

– Poor eye hand coordination

– Visual motor integration (fine motor, gross

motor)

• Clumsiness

– Visual vestibular integration

• Disorientation

• Poor spatial judgments


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Summary

• The visual process is intimately woven

throughout the entire brain

• Even a “mild concussive event” can result

in serious compromise to the neural

substrate, neural software, of the brain

• This can lead to serious visual problems

that require neuro-optometric vision

rehabilitation Drs. Fortenbacher, Stull, Edwards - MVTSG

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An effective neuro-optometric vision

rehabilitation model based on the

principles of:

• Learning dependent neuroplasticity

• Top-Down (intrinsic motivation) processing


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A model based on 5

Elements

1. Intrinsic motivation and engagement

2. Variety and repetition

3. Feedback

4. Motor match to sensory mismatch

5. Intersensory Loading and integration


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Lenses

• The role of the lens

– Refractive correction-

– Aid accommodation- • Influence binocular vision via AC:A

– Aid spatial awareness

– Aid peripheral awareness

– Aid focal-ambient integration • http://maunsell.med.harvard.edu/Downloads/publications/87bMaunsell.pdf

• http://www.oepf.org/jbo/journals/2-1%20Marrone.pdf


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http://maunsell.med.harvard.edu/Downloads/publications/87bMaunsell.pdf

http://www.oepf.org/jbo/journals/2-1 Marrone.pdf



Prisms

• Compensatory

• Spatial


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Yoked Prisms


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Bi-nasal occlusion

• Diplopia management

• Emphasize peripheral

awareness

• Facilitate focal ambient

integration


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A model based on 5

Elements

1. Intrinsic motivation and engagement

2. Variety and repetition

3. Feedback

4. Motor match to sensory mismatch

5. Intersensory Loading and integration


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Spatial Floor Plan

• Alyson Olmstead, COVT


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Spatial Floor Pattern

• Intersensory Loading-yoked prisms

• Feedback-draw and compare pattern

• Variety and Repetition- complexity of patterns, memory, reverse steps, draw

out patterns Drs. Fortenbacher, Stull, Edwards - MVTSG

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Modified Marsden Ball Rail Walk

• Monica King, COVT


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Modified Marsden Ball Rail Walk

• Variety and Repetition- yoked prisms, peripheral stimuli, fixation target

• Motor match to sensory mismatch- yoked prisms

• Intrinsic Motivation and Engagement- maneuver safely in home and in

public


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Multi-Matrix

• Debra Irwin, COVT


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Multi-Matrix

• Intrinsic Motivation and Engagement- sports vision and competition

• Motor Match to Sensory Mismatch- yoked prism

• Intersensory Loading and Integration- vestibular, auditory, yoked prism

• Variety- patterns, different setup or instructions


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Our patient Thomas

• Age – 17

• Myopia

• Excellent student

• Stellar tennis player- rated in the state

• Suffered head injury from a fall in January

2012

• Dx: Post Concussive Syndrome


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Thomas’ Neuro-optometric

Diagnosis

• Post Trauma Vision Syndrome (PTVS)

• Oculomotor dysfunction


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Thomas video before and after

neuro optometric vision rehabilitation


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1.22.14.Thomas.TBI Video.mp4

Questions


2014 MCO

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