Tina Dang Aldana, M.A., O.D., F.A.A.O. 28 October 2018 Aarhus, Denmark COPE NO

Transcription

1 Tina Dang Aldana, M.A., O.D., F.A.A.O. 28 October 2018 Aarhus, Denmark COPE NO

2 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 or self-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)

3 TBI Classification Mild Moderate Severe Glascow Coma Score Imaging Normal Normal or Abnormal AOC 0-1 day > 1 day LOC 0-30 minutes >30 min & < 24 hours > 24 hours PTA 0-1 day 1-7 days > 7 days

4

5 Diffuse Axonal Injury Sudden acceleration-deceleration of the head Gray matter density vs white matter density Shearing of neuronal axons which traverse the junction of gray and white matter Damage not visible on standard imaging CT/MRI

6 Diffuse Axonal Injury 2 Phases of Injury Primary injury: Axons undergoing shearing forces are stretched at the moment of impact Secondary (delayed) phase: Bulb formations Stretched axons undergo swelling and rupture Degeneration process and Clinical symptoms may take up to 2 years to fully develop

7 TBI Pathophysiology

8 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

9 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 Jan;88(1):1-6. doi: /PHM.0b013e

10 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

11 Conceptual Model Pyramid (Ciuffreda 2015) Depression, Fatigue, Cognitive, Behavioral, Attentional, Medical, Neurological problems Non-Visual- Based Problems Non-Oculomotor- Based Problems MLSS, Photophobia, Vestibular defects, VF defects, VIP Oculomotor-based Problems (Version, Vergence, Accommodation) Basic Vision Examination (Refractive Error and Ocular Health)

12 Hierarchy of Vision Subcortical Information processed First and faster 20% Peripheral Retinal Unconscious Vision (nonplanned reflexes) Proprioception Vestibular Cortical Information processed Secondary and Slower 80 % Central Retinal Visual Cortex Subconscious Vision (learned reactions) Conscious Vision Peripheral Awareness Organization Eye Sight Visual attention

13 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

14 Post Trauma Vision Syndrome Vision is processed in the midbrain and occipital cortex

15 Post Trauma Vision Syndrome Disruptions in nonvisual pathways have an impact on patients ADLs Perceived distortions affect the nervous system: concentration and performance

16 Brain Functions Occipital 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

17 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

18 Vestibular Ocular Dysfunction DTI findings suggests central axonal injury underlies vestibulopathy and ocular convergence insufficiency after mild traumatic brain injury Compared with control subjects, patients with mild TBI and vestibular symptoms had decreased neurocognitive test scores and FA values in the cerebellum and fusiform gyri Patients with ocular convergence insufficiency had diminished neurocognitive test scores and FA values in the right anterior thalamic radiation and right geniculate nucleus optic tracts Cerebellar injury showed an inverse correlation with recovery time Anterior thalamic radiation injury showed correlation with decreased processing speed Radiology Jul;272(1): doi: /radiol Epub 2014 Apr 15.

19 Balance & Illusions of Movement Dizziness and Balance Problems Related to Vision Vision plays a significant role in balance. Approximately 20% of the nerve fibers from the eyes interact with the vestibular system. There are a variety of visual dysfunctions that can cause, or associate with dizziness and balance problems. Sometimes these are purely visual problems, and sometimes they are caused from other disorders such as stroke, head injury, vestibular dysfunction, deconditioning, and decompensation.

20 Visual Dysfunctions Causing Dizziness and Balance Problems Aniseikonia Binocular Vision Dysfunction Double Vision Vertical Imbalance Ambient Visual Disorder Eye Movement Disorders

21 Visual Motion Sensitivity Visual motion sensitivity to peripheral movement Supermarket Syndrome Bi-nasal Occlusion (BNO) VEP documented improvement in Patients with TBI Decreased amplitudes in Patients w/o TBI

22 Visual Evoked Potential (VEP) to evaluate the visual pathway

23 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

24 Binasal Occlusion & BI Prism Tape or Nail Polish Tapered to allow for convergence at near Adjust the placement based on Patient perception/performance

25 Ocular Tilt Reaction Central Vestibular Disorder Vertical vestibulo-ocular reflex Unilateral peripheral vestibular deficit (inner ear or vestibular nerve)

26 Ocular Tilt Reaction Double Vision Tilt in the subjective visual vertical

27 Ocular Tilt Reaction Skew deviation (commitant hypertropia) Head tilt in the direction of ocular torsion/ toward the hypotropic eye Ocular torsion in the same direction as the head tilt (clockwise with head tilt left; counterclockwise with head tilt right)

28 Ocular Tilt Reaction

29

30

31 Abnormal Egocentric Localization Mismatch between objective direction of straight ahead and subjective sense of direction May be present in up to 30% of mtbi patients

32 Midline Shift Syndrome Results from dysfunction of the ambient visual process Caused by distortions of the spatial system causing the individual to misperceive their position in their spatial environment This causes a shift in their concept of their perceived visual midline. This will frequently cause the person to lean to one side, forward and/or backward.

33 Abnormal Egocentric Localization MLSS

34 Prisms Yoked prisms Light bends toward the base Yoked Prism Walk Diagnostic vs Therapeutic Affected area of the brain Retinal Mapping Inferior retina Temporal lobe (Base Down) Superior retina Parietal lobe (Base Up)

35 VT: Spatial Localization Walking Rail Spatial Pegboard Interactive hand-eye coordination activities Encourage peripheral awareness

36 Light Sensitivity Brain injury is often accompanied by increased light sensitivity and general inability to tolerate normal glare. Abnormal discomfort from normal light levels up to 50% of patients The problem seems to be an inability of the brain to adjust to various levels of brightness. It is as if one had a radio and the volume control was broken and you could not make the adjustments you normally do to control loudness.

37 Photosensitivity Photosensitive retinal ganglion cells detect background illumination, projecting directly to the thalamus (regulates perceptual sensations) TBI can result in thalamic damage and dysregulation of incoming signals Poor regulation/suppression of back ground lighting intensity results in enhanced sensitivity to light Threshold of pain stimulus is reached

38 Photosensitivity Consider: Pupillary basis Tinted lenses may promote visual adaptation over the long-term Avoid chronic dark adapted state Post Trauma Vision Syndrome patients may experience improvement in light tolerance when treated with neuro-rehabilitation

39 Tints Selective filters, particularly amber filters are often used by brain injury patients. FL41 50% filters 480nm wavelengths of light = peak activation range of retinal ganglion cells Migraine and Blepharospasm

40 Tints Blue spectrum filters: Bend light more toward central retina Red spectrum filters: Bend light toward peripheral retinal

41 OM Disorders

42 OM Disorders Eye movements Saccades Pursuits

43 Reading Disorders Reading tasks require complex sensory motor cognitive functioning Can be damaged at many different levels Individuals with PTVS begin to look at paragraphs of print almost as isolated letters on a page and have great difficulty organizing their reading ability.

44 Reading Acuity falls sharply with increasing eccentricity Minimum size of reading visual field 2 o to the left and right of fixation, 1 o above and below Total perceptual span during a moment of fixation can be extended up to 5 o in the direction of reading

45 Reading Disorders Considerations Refractive error Poor accommodation Poor binocularity: Convergence Insufficiency Visual Field Defects within 5 o eccentricity Motor disturbances: Ocular Motility / Gaze Control Developmental Dyslexia

46

47 Visual Perception Visual-Motor Integration - Eye-hand, eye-foot, and eye-body coordination Visual-Auditory Integration - The ability to relate and associate what is seen and heard Visual Memory - The ability to remember and recall information that is seen Visual Closure - The ability "to fill in the gaps", or complete a visual picture based on seeing only some of the parts Spatial Relationships - The ability to know "where I am" in relation to objects and space around me and to know where objects are in relation to one another Figure-Ground Discrimination - The ability to discern form and object from background

48 Visual Information Processing Dysfunction

49 Vision Rehabilitation TBI effects are complex and vary from person to person, no two brain injuries are the same Patient education and Feedback is key! Emphasize awareness and attention Survey Symptoms Discuss clear goals Rehab goal is to correct maladaptive behaviors, habits and patterns

50 Vision Rehabilitation Correct refractive error Added lens power Prism: horizontal then vertical VT Tints, Yoked prism, BNO

51 Symptom Survey 112 total points 0-28 Mildly symptomatic Moderately symptomatic >84 Severely symptomatic

52 Progressive Return to Activity

53

54

55 Contact: Tina Dang Aldana