1. Neuro-rehabilitative Optometry Kevin E. Houston, O.D., FAAO Clinical Assistant Professor Vision Rehabilitation Services Indiana University School of Optometry [email_address]
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3. Rehab Multidisciplinary Team PM&R (Physiatry) Rehab Psychology and Neuropsychology Therapy Occupational Speech Physical Vision Therapeutic Rec Rehab Optometry Nursing Case Management
43. A E U C G T O M A E U C G T O M H G N X Z J A L K J L D O W U O V R ◙ Case L J: Eccentric Viewing
44. The first place that I can well remember was a large pleasant meadow with a pond of clear water in it. Some shady trees leaned over it, and rushes and water-lilies grew at the deep end. Case L J: Optokinetic Therapy Bl-opt-iusoeachingOW VISION INDYournal Articles-->Optokinetic Therapy Spitzyna GA, Wise RJ, McDonald SA, Plant GT, Kidd D, Crewes H, Leff AP. Optokinetic therapy improves text reading in patients with hemianopic alexia: a controlled trial. Neurology. 2007 May 29;68(22):1922-30.
65. Corbetta’s Attentional Networks Nature Reviews Neuroscience 3 ; 201-215 (2002); doi:10.1038/nrn755 CONTROL OF GOAL-DIRECTED AND STIMULUS-DRIVEN ATTENTION IN THE BRAIN BLUE=Dorsal Attention Network Red=Ventral Attentional Network Temporal Parietal Lobule and Superior Temporal Gyrus
67. Comparisons of Treatments Arene NU, Hillis NE. Rehabilitation of Unilateral Spatial Neglect and Neuroimaging. Eura Medicophys 2007 43; 255-69 # of exposures Onset Success Rate (%) Degree of Improvement Duration of Improvement Generalization of Acquired Skills Prism Adaptation 1 immediate 100 significant At least up to 5 weeks with 2 weeks of tx Yes Visual Scan and perceptual training Several over 1-2 months Prolonged >90 significant 6-8 weeks Partial Optokinetic Training 1 immediate 100 partial Minutes No Vestibular Stimulation (caloric or glic 1 immediate 79-89 significant Minutes No Neck Vibration 1 immediate 93 significant At least 3 weeks with repeated tx. No Dopamine Agonists variable variable variable significant variable No
68. Comparison of Treatments Viewer Centered Personal Anosognosia Representational Stimulus Centered Sensory Extinction Prism Adaptation Yes Yes Yes Yes Vestibular Stimulation (caloric or glic Yes Yes Yes Yes Yes Optokinetic Training Yes Yes Yes Neck Vibration Yes Yes Yes Yes Visual Scan and perceptual training Yes
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75. Effects were increased 2hrs later Rossetti Y, Rode G, Pisella L, et al. Prism adaptation to a rightward optical deviation rehabilitates left hemispatial neglect. Nature 1998; 395:166–169.
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77. Results on BIT Effects of prism treatment on the patients’ performance (percentage of correct responses) in the BIT battery (BIT-C = BIT conventional; BIT-B = BIT behavioural) for the experimental group (EG) and the control group (CG) as a function of time: before treatment (first session) and 2 days, 1 week and 5 weeks after treatment (second, third and fourth sessions, respectively).
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80. Mechanism of Action of PA Therapy Pisella L, Rode G, Farnè A, Tilikete C, Rossetti Y. Prism adaptation in the rehabilitation of patients with visuo-spatial cognitive disorders. Curr Opin Neurol. 2006 Dec;19(6):534-42. Right cerebellum and Left Hemisphere blood flow increase correlated with neglect score improvement
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82. An Anatomo-Functional Model A visual error signal is created in the right hemifield… In the case of a rightward field shift, VES info is transferred to the vermis of the right cerebellum where realignment takes place. A separate network in the cerebellum contralateral to the hand being used is also activated allowing for the appropriate motor response. ..and travels to the left occipital cortex Temporal and frontal cortex and the PPC have been shown to be targets of output from the cerebellum via a neuronal loop also implicating the dentate nucleus and subcortical structures, such as the thalamus and the globus pallidus (GABA)
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Editor's Notes
Give you an idea of tests I do with these patients. HPI, get patient age, race, gender, handedness, date and location of stroke, visual symptoms noted by patient, sx noted by family/therapists. FODLAR out symptoms. Acuity: Trouble finding chart, trouble with VFG (isolate letters), Aphasia matching Lea, FC Teller, Pref Look, OKN drum. Functional Scan
This is a single field analysis plot from a 30 degree visual field. You are seeing plot for right eye left eye. It is best to look at the pattern standard deviation plot which is in the lower right. Where is the defect, left or right? Right Is it in both eyes on the same side, Homonymous? Yes Homonymous Is it a sector, quadrant, or hemi pattern? Hemianopsia Is it congrous (mostly identical) or incongrous different in each field? Congruous
Where is the defect, left or right? Right Is it in both eyes on the same side, Homonymous? Yes Homonymous Is it a sector, quadrant, or hemi pattern? Quadranopsia Is it congrous (mostly identical) or incongrous different in each field? Congruous You won’t know fovea for sure unless amsler grid is done.
Where is the defect, left or right? Left Is it in both eyes on the same side, Homonymous? Yes Homonymous Is it a sector, quadrant, or hemi pattern? Hemianopsia Is it congrous (mostly identical) or incongrous different in each field? Very Congruous
Where is the defect, left or right? Bitemporal Is it in both eyes? Yes Homonymous or Heteronymous? Heteronymous Is it a sector, quadrant, or hemi pattern? Hemianopsia Is it congrous (mostly identical) or incongrous different in each field? Congruous
Computerized visual field testers are nice and are the standard of care for optometry, but as SLP’s you are not likely to have access to one so I will demonstrate and easy and accurate way to get visual field information. The technique here is called confrontations.
Confrontation visual field testing is not sensitive enough to pick up central visual field loss. Our options are to run a separate 10 degree field, or even quicker and easier, run an Amsler grid test. This isn’t to scale here but you bring a small black target against the white target at the speed shown several times and mark the border of the defect. On the actual Amsler grid, each box is 1 degree at the 50cm standard working distance.
1. Treatment focuses on the patient becoming aware of their condition Diller and Weinberg ([11], p. 67): This is particularly difficult in hemi-inattention since this failure in awareness appears to be at the heart of the patient’s difficulty’.
Rubens Proposed the subject felt as if they are constantly rotated toward the lesion side. Poured cold water into the neglect patient’s left ear, instantly produced a dramatic, although transient improvement of neglect.
Rubens Proposed the subject felt as if they are constantly rotated toward the lesion side. Poured cold water into the neglect patient’s left ear, instantly produced a dramatic, although transient improvement of neglect.
Scanning along a line of text is affected if the RHH encroaches to within 5 degrees of fixation, and most symptomatic patients have the central 2-3 degrees involved. As you can imagine, new glasses will not help, and instead eccentric viewing and visual scan therapy is indicated. You may have seen the glasses with a prism drilled in one corner known as the Gottlieb lens or VFAS, this is more for mobility and in my experience doesn’t help reading. Pure Alexia, characterized by an inability to recognize words, should be suspected in patients with reading speeds less than 40 wpm. In this condition the fusiform gyrus is damaged, remember the pink part of the brain from the other slide? These patients clue you into to their problem by spelling out their words letter-by-letter. Patients with hemianopic alexia might do this, but only occasionally. Sometimes it is hard to catch them in the act and simple flash cards without pictures presented quickly to prevent the letter by letter strategy will reveal the condition. It is important to note that the patient may not be aware that they are using a letter-by-letter strategy until the examiner proves it to them. When doing a literature review I ran across a technique where the patient is shown pictures with the word to try to access semantic stores through a pictorial route, which is theoretically intact and in the right hemisphere. Perhaps this will turn out to allow faster reading speeds in some of your patients with pure alexia.
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This is the protocol used in the IU school of optometry clinics. Scores on the vision evaluation are used to decide whether or not to proceed with training. If there are multiple high risk factors and a low chance for success, I let the patient know up front. I always warn them that even with training we may not be able to reach the goal of safe driving. We can use any treatments we want to help them compensate for deficits, but the final litmus test is always the same: Have to pass the on-the-road evaluation with the CDRS. During the evaluation and training period the patients are always educated on their risk and that I recommend not driving. In Indiana, unfortunately, I cannot report or request a courtesy drive without the patient’s signed consent. Different states have different rules, and in some States, reporting is required.
The evidence base evaluation is based on the SEE study and done at the beginning to assess risks, and the end to see how we improved.
Patients with any type of field defect cannont compensate for the defect if they don’t know where it is and understand that it moves when the eye moves. These patients are in denial that they miss things. They say “Oh I see it now” or “I just wasn’t ready”. They will deny it until you force them to recognize it. Most times they only report that they miss things or bump into things because they have been told repeately that they do this. Even still, they will often tell you the eye on the side of the defect is blind, or may even confuse which side the problem is on. The especially don’t realize that the blind spot moves with the eye, causing them to run into things directly in front of them if they are gazing away from the defect. The things must be demonstrated by a vision specialist who has measured and understands the location and depth of the hemi field defect.
Many subtypes of neglect have been defined over the years based on symptoms described. Work is underway in laboratories using fMRI and Transcranial magnetic stimulation (TMS) to better define the substrates related to the symptoms. Patients typically have multiple subtypes. Knowing which subtypes to expect based on the location of the injury is becoming more feasible and I will clue you in on what I know. Clearly I am more likley to pick up on the visual symptoms of neglect than other members of the rehab team. I have found it most useful in the clinic to take what has been documented in prior reports and add it to my diagnosis. For example, Patient AM was referred to me with symptoms of motor neglect as noted by the OT. A prior report by the neuropsychologist defined personal and peripersonal neglect. I found the patient had viewer centered neglect, only crossing out items to the right of midline on a line crossing test. They also re-cancelled many of the lines that had already been cancelled. My assessment included previous assessments as well as mine: Dense Viewer-centered personal and peripersonal neglect with bias for rightward stimuli and revisiting previously searched locations. In the next slide I will discuss what that means.
The subtype I see most commonly is viewer centered neglect. This is a condition of the patient’s egocentric reference frame, which is the part of the brain that monitors center of the body. This is a multmodal system of proprioception and vision. Patients with severe viewer centered neglect do not orient to sensory stimuli in the left hemifield. They may lean to the right and not fix and follow past midline. Even mild cases tend to have extinction of the left field. Viewer centered neglect patients are believed by researchers to have a corresponding injury to the Right Angular Gyrus (gold) and Intraparietal Sulcus (yellow line). The superior division of the MCA feeds this part of the cortex.
Stimulus Centered (patient neglects the left side of the stimulus, even if it is in the right hemispace): Right Superior Temporal Gyrus Visual Search: Right Superior Temporal Gyrus
This is the classic drawing a person with left neglect will exhibit. This is just a symptom of the condition. If a patient draws a picture like this, they definitely have neglect, but if they draw normally it doesn’t mean they don’t have neglect. You have probably also heard patients with neglect only eat food off one half of the plate. I am hear to tell you this is sometimes true, but more often not. In fact I have seen patients test out completely normal on paper and pencil tests and then seen them exhibit severe neglect behaviorally in a noisy lunch room. Perhaps we should start doing our test there.
2 distinct attentional networks have been defined, a dorsal and a ventral. These should not be confused with the dorsal and ventral visual pathways, although they are similar in concept. The Dorsal stream, in blue, has not been correlated with neglect symptoms. It is involved in selective spatial attention during visual search tasks and eye hand coordination. The ventral attentional network is correlated with neglect. A balance is believed to exist between the 2 networks that is thrown out of whack when the ventral network is damaged. This contributes to symptoms of neglect that seem to be unrelated to the area injured. inferior parietal lobule [IPL; Mort et al., 2003;Vallar and Perani, 1987] superior temporal gyrus [STG;Karnath et al., 2001, 2004] subcortical nuclei [Karnath et al., 2002; Vallar and Perani, 1987] inferior frontal cortex [Husain and Kennard, 1996; Vallar and Perani,1987]
Treatments related to reflexive orienting do not involve learning, adaptive processes are not engaged.
Beginning with Herrmann von Helmholtz in the late 19 th century in Germany who viewed PA as illustrating his perceptual learning theory Ivo Kohler, Innsbruck Austria, systematically studied prism adaptation. Richard Held at MIT and Charlie Harris at Bell Labs conducted foundational research Gordon Redding at Illinois State and Ben Wallace at Cleveland State have researched this topic since the 1970’s and remain the leading experts on the mechanics of sensorimotor adaptation. Eve Ro’ss etti and collegues at the INSERM lab in Bron, France.
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