Concussion Management and Visual Deficits HELENE BENNITT OTR/L, AIB-CCON

Transcription

1 Concussion Management and Visual Deficits HELENE BENNITT OTR/L, AIB-CCON

2 Objectives Theories behind concussion Concussion presentations Concussion management: multidisciplinary approach Assessing for visual deficits Basic treatments for visual deficits

3 Theories behind concussion: structural or/and metabolic Structural: indirect forces cause acceleration or deceleration and can stretch, shear, or tear neurons (i.e. coup contrecoup). This can effect both upper and lower motor neurons. Structural damage can be the only cause of the concussion. Metabolic: linked to structural damage. Neuronal depolarization, release of excitatory neurotransmitters, ionic shifts Neurometabolic Cascade: massive efflux of K+ which causes a brief period of hyperglycosis followed by persistent Ca2 influx. This creates mitochondrial dysfunction with decreased oxidative metabolism.

4 Most Common Signs of Concussion Headache or feeling pressure in the head Temporary loss of consciousness Confusion or feeling as if in a fog Amnesia with regard to the traumatic event Dizziness Ringing in the ears Nausea Vomiting Slurred speech Delayed response to questions Fatigue

5 Second Impact Syndrome This is the result of suffering another concussion before the prior concussion is properly healed. This can occur during the same game, or days or weeks later. Symptoms can include: Dilated pupils Loss of eye movement Unconsciousness Respiratory failure Death

6 Concussion Timeline Individuals should recover within 7-10 days from the event with rest. If not, then the individual will require further treatment and likely presents with postconcussion syndrome.

7 Concussion Cascade The cerebral pathophysiology can be present for weeks in patients. Symptoms can affect all aspects of occupation and quality of life, which is why rest is important i.e. limiting school-based and work-based activities; computer/tv usage screen time ; limiting physical activities i.e. sports, recreational activities; limiting socialization; maintaining a daily routine with adequate sleep. Stressing the brain causes the symptoms to worsen.

8 Post-Concussion Syndrome Dizziness Fatigue Vertigo Anxiety and/or depression Headaches Insomnia Diplopia Irritability Blurry vision Ringing in the ears Noise sensitivity Light sensitivity Impaired attention and concentration Impaired short term memory Rarely: decreased taste and smell

9 Risk Factors for post-concussion syndrome Age: Studies have found that increasing age is a risk factor. Gender: Women are more likely to be diagnosed with post-concussion syndrome, however, women are generally more likely to seek medical treatment. Previous diagnosis of PTSD.

10 Concussion Management Decision Tree Head Impact Medical Evaluation Neuropsychologist, Primary Care Physician, Chiropractor, Neurologist, Orthopedist Possible Cognitive Assessments: IMPACT, Buffalo Concussion Treadmill Test, Psychometric Testing Vestibular Assessment Visual Rehab Assessment Counseling

11 Concussion Management: ideal scenario After a concussion is suspected, the patient is referred to a neuropsychologist having a practice based in concussion management. The neuropsychologist performs appropriate assessments, monitors the patient s recovery, and recommends appropriate medications, therapies, as well as return to work, play, exercise, etc.

12 Part of our scope of practice: What is visual perception? Visual perception is the ability to see and interpret, analyze and give meaning to, the visual information that surrounds us. The process of taking in one s environment is referred to as perception.

13 How does the brain process visual information? Visual information from the retina is relayed through the lateral geniculate nucleus of the thalamus to the primary visual cortex, which is located in the occipital lobe.

14 Our Visual System There are two modes of visual processing: a central or focal process and a peripheral or ambient process. Both modes process visual input together and are integrated, however, they involve separate neurological pathways. The majority of visual processing and ocular alignment problems are not a result of weak eye muscles, but is a result of a disruption of visual pathways.

15 Our Visual System The visual system is the part of the Central Nervous System which gives humans the ability to see the world around us. It provides information that allows us to process light through a photochemical process that occurs as a result of rod and cone stimulation in order to build a representation of the individual s environment. There are three subsystems that create the visual system: Parvocellular, Magnocellular, and Koniocellular. However, the Parvocellular and the Magnocellular are the two subsystems that are the focus in visual rehabilitation.

16 Our Visual System The Parvocellular Emanates from the foveal area and provides information or central vision Responsible for detail, color, patterns, fine textures i.e. reading. The WHAT of the visual system The Parvocellular is accountable for 85% of the visual system

17 Our Visual System The Magnocellular Emanates from the extra-foveal region or peripheral vision Responsible for motion detection and spatial relations Allows us to keep our place while reading Judges distance from objects, such as reaching for a drink The WHERE and the WHEN of the visual system The Magnocellular is accountable for 15% of the visual system

18 Screening: Things you can look for Acuity: far and near (if time is available and you have eye charts) Cover Test Pupil appearance Pupillary Light Reflex Consensual Light Reflex Convergence Pursuits Saccades Divergence Ask when was their last eye exam

19 Cover Test Have patient fixate on a focal point that is at reading distance ~12 to 14, and cover each eye separately. Normal: no change in eye position observed. Abnormal: If the eye moves temporally or nasally.

20 Cover Test **Inquire if patient has a history of amblyopia, strabismus, or lazy eye. If the answer is no, then retest if test is abnormal then send patient to their optometrist or ophthalmologist. If the answer is yes, then continue assessment. (Limited treatment available for this patient, but they likely present with motion sensitivity that needs to be addressed.)

21 Pupil Appearance Look for symmetry and size of the pupils. Normal: 3-4mm. Constricted: 2mm or less in diameter. Requires increased lighting for tasks. Dilated: >4mm in diameter. Requires reduced lighting for tasks i.e. light sensitive.

22 Pupillary Light Reflex Procedure: Patient should focus on an target 6 or greater in a semi-dark room without glasses, examiner will shine penlight directly into the patient s eye from 3-4 inches away for 2 seconds and observe the pupil response. Normal Response: Both eyes should constrict quickly and remain constricted i.e. responds well/intact. Impaired Response: May indicate localized disease, iritis, optic nerve disorder, brainstem dysfunction, retinal disease, or a cranial nerve lesion. i.e. sluggish /slowed response; does not respond. Alpha Omega pupils: Constrict then dilate. Due to being in Fight or Flight. (Often due to impaired sleep/wake cycles or an overstimulated CNS i.e. screen time; PTSD; anxiety.)

23 Consensual Light Reflex Procedure: Patient should focus on a target 6 or greater in a semi-dark room without glasses, examiner will shine penlight directly into the patient s eye from 3-4 inches away for 2 seconds and observe the pupil response in the opposite eye. Normal Response: Both eyes should constrict quickly and remain constricted. Abnormal Response: Sluggish constriction, dilation or no constriction.

24 Near Point Convergence testing Methods to test Near Point Convergence (NPC): accommodative target, a penlight, and a penlight with red and green glasses. All three methods are acceptable. The target or penlight is placed in front of the patient at 24 inches a little below eye level, and the patient is asked: How many targets/lights do you see? The answer should be one. Then, move the target toward the patient s nose and ask them to tell you as soon as they see two. When they report two objects that is the break or breaking point. Do this three times. On the third time, you will ask the patient when they see two and then when they see one object again this is the recovery. Normative values for elementary school aged children is between 6 cm to 10 cm (2.36 inches to 3.93 inches). Normative data for the break and recovery for adults: Break: 5cm; Recovery: 7cm (Break: 1.96 inches; Recovery: 2.76 inches.)

25 Pursuits Procedure: (generally remove glasses) Patient is asked to follow a moving target placed 20 from face in 8 of the cardinal directions of gaze (up-top of head, down-chest level, diagonal upper right, right, diagonal lower, diagonal upper left, left, diagonal lower left). Note deviations from fixational point. Normal Response: eyes move smoothly and together. Abnormal Response: corrective saccades, nystagmus.

26 Saccades Procedure: (generally remove glasses) Patient is asked to alternate between two targets placed 6 apart in 8 cardinal directions of gaze (i.e. horizontally, vertically, diagonally). Normal Response: eyes move together to target consistently. Abnormal Response: undershoots target, overshoots target, delay.

27 Divergence screening Have patient stand 11 from a small distant target placed at eye level. Patient holds pencil as fixational target at normal reading distance (~12 to 14 ) and at midline. Patient alternates looking from pencil to the distant target and back again as quickly as possible as long as they are aware of physiological diplopia (i.e. seeing 1 of the object that you are looking at and 2 of the other). Normal: eyes alternate at same rate of speed. Abnormal: eyes moving at different rates of speed, which indicates a deficit in eye teaming when eyes are moving from a near to a far target and from a far to a near target.

28 What to do if possible cranial nerve involvement is suspected? Refer to a neuro ophthalmologist, optometrist, or ophthalmologist.

29 Visual Rehabilitation Relies on the neuroplasticity of the brain, and biofeedback mechanisms i.e. auditory, visual, tactile. For concussion, rehabilitation is a process of re-wiring the visual system s interaction with sensory and cognitive abilities as well as central-peripheral integration Visual Acuity should be at it s optimal level prior to beginning therapy

30 Visual Rehabilitation Physiological diplopia is used to enhance and build fusional reserves for convergence and divergence i.e. Brock string Improvement in visual abilities is reinforced with the integration of tactile and movement i.e. hand-eye coordination activities Grade activity accordingly: if it can be done standing--stand, ambulating, ambulating in a large circle and changing directions occasionally, ambulating in a small circle and changing directions occasionally.

31 Important Considerations When treating someone that has suffered a concussion or mild TBI use these guidelines: Obtain visual attention before initiating treatment Educate and explain the activity and what they should experience All techniques should provide feedback to the patient

32 Important Considerations Work at the level of the patient s current performance Patients symptoms should increase some during treatment Progressively increase the demand of the technique Integrate the visual skill into activities of daily living

33 Definitions Divergence excess: a condition in which the eyes drift outward when looking at a distance and function normally when looking a near objects Convergence excess: a condition in which the eyes have a tendency to turn inward rather than outward. Convergence excess has been found to be slightly more prevalent than convergence insufficiency in a clinical population. Convergence insufficiency: a condition in which the eyes have a tendency to drift outward when being used for near work such as reading, while at a far distance the eyes work well together.

34 Definitions Saccadic dysfunction: a condition in which the accuracy and speed of saccadic eye movements are reduced relative to expected findings for the individual s age. Physiological Diplopia: a normal phenomenon, and happens when an object that is outside the point of fixation is seen as double.

35 Rule For every 20 minutes of performing a near task (i.e. computer, tablet, phone, reading a book or magazine), look at an object at least 20 away for a FULL 20 seconds. This allows a rest break for our eyes. Our eyes need rest breaks from near tasks or the eyes begin to feel strained or fatigued. Very important for individuals with computer-based occupations, but this rule should be utilized by everyone.

36 Physiological Diplopia and Convergence Activity Addresses convergence deficit. Explain physiological diplopia prior to initiating activity. Have patient hold two pencils at midline, one at arm s length and the other at reading distance, fixate on the near pencil. Ask the patient if they see one pencil in front of them and two in the back. Then, have the patient move the near pencil as close to their nose as they can with still maintaining a single pencil in the front and two in the back. Once the patient understands the activity, then have them sustain convergence at near for 5 or 10 seconds for 10 repetitions. Grading the activity: Have the patient alternate fixation from the near pencil to the far pencil as the near pencil is moving. To make the activity a dual-task, add alternating fixation. This will address attention/concentration. To further grade the activity, add ambulation, etc.

37 Thumb Rotations/Coin Circles Addresses pursuits, motion sensitivity, central and peripheral vision integration. Have patient focus on thumb or coin that they hold between 1 st and 2 nd digits, and makes a 12 circle with their arm. Perform clockwise for 2 minutes, then counterclockwise for 2 minutes. How to grade this activity: standing, ambulating in a straight line, ambulating in a figure-8 ( cones ~5 to 6 apart). Standing: if swaying observed do not progress to walking yet. Walking: if ankle strategies observed do not progress to walking in a figure-8 yet.

38 Brock string 10 to 12 Addresses eye teaming, fixation, convergence, divergence, and jump vergences. Have patient hold end at the nose, while the other is tied to a fixed point or closed in a door. There are usually 3 to 5 beads, the beads are placed at different distances (spacing depends on what you are attempting to accomplish), and the patient must focus on each bead. When the patient is focused on a bead, they should be seeing one bead, two strings going into the bead and two strings going away from the bead i.e. physiological diplopia. For individuals that have difficulty with fixation: have them sustain fixation on each bead for 30 seconds in 10 minute time span. For individuals that need to address eye teaming: have them sustain fixation on each bead for 10 seconds in a 10 minute time span.

39 Far/Near Rock Addresses divergence, convergence, jump vergences, and attention/concentration. Have patient stand 11 from a small distant target placed at eye level. Patient holds a pencil at normal reading distance (~12 to 14 ) and at midline. Patient alternates looking from pencil to distant target and back again as quickly as possible as long as they are aware of physiological diplopia (seeing 1 of the object that you are looking at and 2 of the other), then patient moves pencil toward their nose and then away in a continuous motion. 5 minutes if tolerated.

40 Final notes Patients must perform minutes of vision rehabilitation daily to create lasting changes to the visual system and decrease post-concussion syndrome symptoms. Many patients that have suffered a concussion can recover if they perform their home program daily. It s always important to have the patient review their home program at each session (briefly) and assess carryover as well as how to increase the visual and cognitive demand of their home program. Use your clinical judgement!

41 Bibliography Gans RE. (2016). American Institute of Balance: Evidence Based Practices Concussion Certification Course. LaRosa S, Jordan, KW. (2016). Vision Rehabilitation: Understanding and Managing Visual Impairment Across the Continuum of Care. Maples WC. (2014). COVD Critical Concepts Course: Vision Training Conference II. Orsillo R, personal communication, March 13, 2015.

42 Bibliography Scheiman M, Mitchell GL, Cotter S, et.al. (2008). Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children. Arch Ophthalmol. 126 (10): Scheiman M. (2013). Understanding and Managing Visual Deficits: A Guide for Occupational Therapists. Vision Education Seminars. Suter P, Harvey L. (2011). Vision Rehabilitation: Multidisciplinary Care of the Patient Following Brain Injury, CRC Press, New York. Thomas C, Andrich P, Motz V. (2017). Comparison of Three Types of Vision Therapy Exercises on Visual Skills of Sports Performance. Optometry & Visual Performance, 5 (1),