Tina Dang Aldana, M.A., O.D., F.A.A.O.27 October 2018Aarhus, DenmarkCOPE 53554-NO

Disclosure Statement:As a civilian employee working for the United States Army, the views expressed in this presentation are mine and do not represent those of the United States Army, Department of Defense or US Government. I have no financial conflict of interest or disclosure to declare.

Traumatic Brain Injury

A traumatically induced structural injury or physiological disruption of brain function as a result of an external force, that is indicated by new onset or worsening of at least one of the following clinical signs, immediately following the event:

• Any period of loss of or decrease of consciousness, observed orself-reported (LOC)

• Any alteration in mental status (confusion, slowed thinking, disorientation, “seeing stars”) (AOC)

• Any loss of memory for events immediately before or after the injury (PTA)

TBI Classification

Mild Moderate Severe

Imaging Normal Normal or Abnormal

LOC 0 - 30 minutes >30 min & < 24 hours > 24 hours

AOC 0-1 day > 1 day

PTA 0-1 day 1-7 days > 7 days

Diffuse AxonalInjury

• Rotational acceleration forces cause axonal shearing

• Occurs at the white-gray matter junctions

• Not captured on CT and MRI

TBI PathophysiologyMetabolic Injury

Chemical shifts in the brain

Metabolic demands for cellular homeostasis

Neuro-metabolic cascade results in impaired mitochondrial function

Reduced cerebral blood flow: hypoxia and hypotension

Disrupts brain function

Multiple mTBI

• Increased symptoms and lingering effects are reported from subsequent concussions when they occur close in time

• Blast concussions tend to be repeated and have more lingering effects

• Post trauma deficits often lead to subsequent concussions

Signs and Symptoms of TBI

Physical Cognitive Emotional

Headaches Poor concentration Irritability

Sleep Disturbances Loss of memory Anxiety

Dizziness and Balance problems

Attention problems Depression

Fatigue Slowed thinking Mood swings

Visual Disturbances Speech deficits

8 Symptoms Specific to Concussion

1. Headaches

2. Dizziness

3. Intolerance to stress

4. Forgetfulness

5. Poor concentration

6. Taking longer to think

7. Blurred vision

8. Personality change

2013 Study: compared 526 pts with h/o TBI to 946 pts without h/o TBI

High Prevalence of Vision Problems after TBI

Vision Problems Patients with mTBI Normal Population

Convergence Insufficiency

30-40 % 5 %

Accommodative Dysfunction

20-50 % 6 %

OM/Saccadic Dysfunction

20-40 % <5%, age-related

High Prevalence of Vision Problems after TBI

• Half of the circuits in the brain are involved in vision

• Many aspects of the visual system are vulnerable to damage from TBI

• Visual and Nonvisual

Visual Signs & Symptoms

• Blur

• Diplopia

• Headaches

• Dizziness

• Ocular pain

• Poor Visual Concentration

• Difficulty with Reading

• Reduced NPC

• Reduced Fusional Ranges

• Exo deviations

• Reduced Stereoacuity

Psychomotor Slowing

• Damage of cortical components

• Abnormal perceptual interpretation of incoming stimuli

• Abnormal execution of motor responses

Study 2009: compared 22 subjects with severe TBI vs non-TBI subjects, given discrimination tasks and measured perceptual and motor cortical potential by VEP

Am J Phys Med Rehabil. 2009 Jan;88(1):1-6. doi: 10.1097/PHM.0b013e3181911102.

Visual Evoked Potential (VEP)to evaluate the visual pathway

Bi-nasal Occlusion & BI Prism

• Occlude overlapping nasal fields

• Decrease central focus to improve ambient awareness

• Changing the central visual space forces a change in the use of peripheral clues

• Re-establish connection of sensory-motor function to higher focal processing

• Improve balance and reading skills

• Reduce visual stress

Visual Consequences of TBI

• Abnormal motor responses lead to visual consequences

• Viewing objects at close distances requires more convergence

• Uncorrected refractive error can contribute to visual stress

• Refractive error can be caused by postural stress

Visual Consequences of TBI

• Decreased Visual Acuity or Blur

• Diplopia

• Photophobia

• Loss of Visual Field

• Decreased Motor Control

• Visual Balance Disorder

• Psychomotor slowing

Accommodative Insufficiency and Infacility

Convergence Insufficiency

Convergence Dysfunction

OM Disorders

Eye Movements

Eye Movement Disorders

Binocular Monocular

All eye movements affected (Saccades, Pursuits, Vestibulo-

ocular)

Certain types of movements more or

less affected than others (Supranuclear)

Exophthalmos and/or Inflammation of

orbital tissues

No Exophthalmos nor Inflammation of

orbital tissues

Ocular MusclesBrainstem or

HigherOrbit

Cranial nerves III,IV, and/or VI

Visual Efficiency

90% of mTBI Patients have Oculomotor-based Vision Problems

• Vergence Dysfunction (56%)• Convergence Insufficiency (43%)

• Versional Dysfunctions (51%) • Saccadic Intrusions

• Accommodative Dysfunction (41%)

• Strabismus (25%)

• III and IV CN Palsy (7%)

Recovery

• 80-90% of patients spontaneously recover in 2-4 weeks

• 10-20% of patients with persistent signs and symptoms > 3-4 weeks = Post-Concussion Syndrome (PCS)

Post Concussion Syndrome

A complex disorder in which various symptoms last for weeks, months or years after the injurious event

• Headaches/Migraines• Dizziness• Fatigue• Irritability • Anxiety• Insomnia• Loss of concentration and memory• Visual disturbances

Research suggests >50% and up to 95% of patient with PCS have Visual Problems

Post Trauma Vision Syndrome

• PTVS sensory mismatch between subcortical and subconscious cortical levels

• Dysfunctional peripheral nonvisual pathways interfere with central cortical inputs

• Causing problems of central attention and spatial awareness

• Mal-adaptations can cause alterations in postural alignment and balance

Post Trauma Vision Syndrome

• Disruptions in nonvisual pathways have an impact on patients ADLs

• Perceived distortions affect the nervous system: concentration and performance

Neuroplasticity

• After injury the brain reorganizes

• Physically and functionally

Neuroplasticity

• Neuroplasticity allows the neurons in the brain to compensate for injury and disease and to adjust in response to new situations or changes in the environment

• Controlled exercise restores normal cerebral blood flow

• Early aerobic activity right after concussion associated with worse cognitive function

• Exercise after a rest period associated with improved outcomes compared to rest alone

Mechanisms for Effective Vision Rehabilitation

• Neural Synchronization: • Therapy is analogous to a conductor in an orchestra who facilitates the

synchronization of the musicians

• Neural Recruitment:• Therapy persuades neurons which did not previously participate in a task

to now participate

• Functional Connectivity:• Therapy improves the connections between neural sites• Improves the communication between brain regions

Right-sided injuriesVisual Spatial impairmentVisual memory deficits Left neglectDecreased awareness of deficitsAltered creativity and music perceptionLoss of the “big picture”Decreased control over left-sided body movements

Left-sided injuriesDifficulty with languageAnxiety/DepressionVerbal memoryImpaired logicSequencing difficultiesDecreased control over right-sided body movements

Diffuse brain injuries Reduced thinking speedConfusionReduced attention and concentrationFatigueImpaired cognitive skills in all areas

Hierarchy of Vision

SubcorticalInformationprocessed First and faster

20%Peripheral Retinal

Unconscious Vision (non-planned reflexes)

Proprioception

Vestibular

CorticalInformationprocessed Secondary and Slower

80 %Central RetinalVisual Cortex

Subconscious Vision (learned reactions)

Peripheral Awareness

Organization

Conscious Vision “Eye Sight”Visual attention

Retinal Pathways

Subcortical CorticalRetino-tectal (Collicular) Spatial Orientation

• Balance, postureRetino-geniculo-striateFor Peripheral Vision

LocalizationExternal organization• Speed, location, size,

shape

Retino-hypothalamic Circadian Rhythms• Emotional behavior

and sleep patterns

Retino-geniculo-striateFor Central Vision

Identification• Attention• Detail and color

awareness

Accessory Optic System Spatial Visualization• Internal organization

Retino-pretectal Visual-Motor Reflexes• Instinct, avoidance,

attraction

Conceptual Model Pyramid(Ciuffreda 2015)

MLSS, Photophobia, Vestibular defects, VF defects, VIP

Depression, Fatigue, Cognitive, Behavioral, Attentional, Medical, Neurological problems

Visual Processing

Focal Processing

• Occipital Cortex

• Fovea / Central Vision

• Details

• Concentration / Attention

Ambient Processing

• Midbrain

• Peripheral Vision

• Visual System coordinates with Kinesthetic, Proprioceptive, Tactile, Vestibular Systems

• Organizes Spatial Information

Post Trauma Vision Syndrome

Vision is processed in the midbrain and occipital cortex

Visual Processing Disorders

• Saccadic Dysfunction and Visual Tracking

• Reading Problems

• Reading Comprehension

• Visual Memory

• Visual Attention and Visual Neglect

• Post Trauma Vision Syndrome

• Midline Shift Syndrome

Brain FunctionsOccipital Lobe: • Vision

Parietal Lobe:• Spatial perception• Visual perception• Identification of size, color and shapes

Frontal Lobe: • Attention and concentration• Speech• Planning and anticipation• Motor planning and initiation• Organization• Personality

Temporal Lobe:• Memory• Sequencing• Hearing

Cerebellum:• Balance• Skilled motor activity• Coordination• Visual perception

Brain Stem:• Breathing • Sleep and wake cycles• Attention and concentration• Arousal and consciousness

Information Processing

• Integrating incoming information

• Sensory

• Motor

• Cognitive

• Emotional

Recovery

• Most patients spontaneously recover in 2-4 weeks

• Recommendations:• Stage 1: Rest, 24-hour mandated recovery period• Stage 2: Light Routine Activity• Stage 3: Light Occupation-oriented Activity• Stage 4: Moderate Activity• Stage 5: Intensive Activity• Stage 6: Unrestricted Activity

Comorbid Conditions

• Sleep Disorders

• Medication

• Vestibular Disorders

• Headache/Migraine Disorders

• Depression / Behavior Health

Clinical Pearls

• TBI Patients are often hypersensitive to small refractive error

• Consider prescribing even very small amounts of correction

• Required ADD may be higher and in younger patients

• Use added plus for temporary tx during recovery

• Consider prescribing unequal ADDs for monocular AD

• More likely to prescribe smaller amounts of prism

• In-Office VT vs Home-based VT

Questions?

tinaaldana@gmail.com