Posts Tagged Hemianopsia
[Abstract] Computer-Based Cognitive Rehabilitation in Patients with Visuospatial Neglect or Homonymous Hemianopia after Stroke
This is an attempt to show people how I see the world since my brain injury 8 years ago. This is what I see when I’m going shopping… I hate going shopping… I rarely go full shopping….. My left side of vision is missing, it’s not really black, it’s just not there, but I can’t explain it… and what I have left, is what you see here… My camera caught it all perfectly, sun glare as well… So if I don’t recognise you in the street, it’s really because I can’t see your face. If I need to see your face, I look for the right side edge of your face and look above you… that helps me see more of your features. But to be honest, I’ve kind of got used to not seeing people’s faces. I look at the floor a lot so I can see people’s feet, so I can sort of work out where they are if they are too close to me. Gradually, over 8 years I have adapted to doing things, walking, etc on the right. I stop in mid walking sometimes because I saw a person in front of me, then they vanished to my left and I wasn’t sure how close to me they were and I didn’t want to bump into them…. I cope better in wider spaces. Narrow corridors look even more narrow. I discreetly use my hands to touch anything that might be too close, so that I know to move myself away. I still walk into things and get hurt. If I turn my head too quickly, then I go off balance and sometimes fall over. It is very frightening when you can’t see properly, but look normal to everyone else. I’m not too bad if I’m with someone else. I constantly rely on touch… Hence doing Papiér Maché instead of drawing or painting. Also, I still get lost and wonder where I am, even sometimes going past my own house… I haven’t read a book in years, and I used to like reading… I couldn’t work out why I couldn’t see the words properly, and they kept vanishing, and the bits that I could see were double vision – then I had prisms fitted in my glasses lenses, which helped with the double vision, but I still couldn’t work out why I couldn’t see properly. I was officially diagnosed in January 2017. The Neurologist said despite all that, I had made some very good ways of trying to cope… It still is a struggle, but I do my best.
Hemianopia, partial loss of the field of vision, is a condition usually the result of a stroke although other neurological disorders such as tumours can be responsible.
From the Greek; hemi – half, an – without, opia – sight.
Damage to an individual’s brain in the area responsible for interpreting visual input is the most common cause;
Normal field of vision
The thing about hemianopia is that often the person experiencing the condition is unaware. Imagine the entire right side of your world stops existing; your brain, just as with your physiological blind-spot very quickly recovers and compensates.
People who have experienced strokes will not uncommonly eat a meal and leave half the plate, not because they can’t see it (which they can’t), but because for that person there is no right or left side of the plate.
We call this situation neglect. I guess that is apposite.
I first encountered this in Oliver Sack’s case histories. I can remember the story of a man waking-up in bed to find a strange object beside him; inert, disconnected – it was his own leg. (This might have been Alien Hand Syndrome, that is for another day.)
(For this reason, medical students, if you ever talk with someone who has experienced a major stroke, always make sure you are in their field of vision and not presenting as a disembodied voice.)
Once understanding this concept, I thought I would stretch the idea to include the way that certain branches of management operate.
It is all too easy for me to pick hospital management, but, what the heck.
Imagine you are running an organisation – it is perhaps doing OK, books balanced, care, treatment, production all at levels you anticipated at the start of the year; the plan is on plan. Beautiful; you can even go on holiday and chill-out.
If back home things go wrong; I don’t know, perhaps, the money that was thought to be in the bank is actually a deficit or, the equipment you have been using to undertake operations is in some way faulty, you have two options.
One, investigate, get as much information as possible, conclude and communicate.
The other, is to do the above, but pretend all is OK; assume that everything will be well – this, the ostrich strategy you might call it is more common within organisations than at first might seem logical; we have the 2007/8 Global Financial Crisis as a case study.
Much analysis has happened since that time and is ongoing; in healthcare, our equivalent is the Mid Staffordshire Hospitals – is disaster the wrong word*? People running so fast on a treadmill that if they get off the uncertainty is more frightening than their high-speed collapse.
Good, clever, insightful people become blinded to what is obvious; hemianopia. It is there, it is clear to everyone else, but in the case of the afflicted it doesn’t exist.
Other words are lacuna, scotoma, absence.
Through careful therapy, a person can recover from hemianopia – utilising mirror-neurones, physical and psychological treatments, that which was lost can return.
How do we support those caught in management hemianopia to recover? Is there a treatment or a means of defence?
Be open, honest, vulnerable and candid.
Don’t hide behind false prophets or slogans.
Acknowledge that the world is never entirely knowable; accept dissonance. Ask for help.
And, if the humility isn’t there? If the situation is extreme and the walls falling-down?
What would you do?
*Officially it was a ‘scandal’
Hemianopia, also referred to as hemianopsia, comes from a culmination of three different Greek words: “hemi” translates to “half,” “an” translates to “without,” and “opsia” translates to “vision.” Hence, it literally means “being without half of your vision.”
This is a condition where half of your visual field can either be completely blind or partially diminished as a result of head trauma, a tumor, or suffering a stroke.
People who suffer from migraine headaches may sometimes experience temporary hemianopia or other visual disturbances, but this typically subsides on its own after a migraine goes away.
Homonymous hemianopia occurs when you lose part of your visual field on the same side of both eyes. This happens frequently to stroke patients or people who’ve suffered traumatic brain injuries. Visual images that are captured on the left side of the brain are communicated to the right side and vice versa, which is why hemianopia typically affects the same side of each eye equally.
The opposing posterior sides of the brain correspond to the opposite eye, which means that if an injury occurs on the left side of the brain, the visual field defects occur in the right eye.
What are the types of hemianopia?
As an umbrella medical term, there are actually five types of hemianopia and two subcategories in total. In fact, the hemianopia type that a patient suffers from is typically correlated with the exact site of the visual field defect.
Visual field is lost on the same side in both eyes, depending on which side of the brain is affected by a stroke or injury. The left optic nerve controls the right visual field and the right optic nerve controls the left visual field. The diminished vision is instrumental in helping doctors locate the exact area of the brain that’s been injured or where the stroke occurred.
Loss of vision occurs in different fields of the eyes. Heteronymous hemianopia is separated into two different categories:
Binasal hemianopia: Blindness or vision loss occurs in the field of vision that’s within the closest proximity to the nose. This is caused by lateral damage to the retinal nerve fibers that don’t cross in the optic chiasm. They’re also responsible for registering information and sending it to the temporal retina.
Bitemporal hemianopia: As the name suggests, bitemporal hemianopia is a loss of vision that happens on the side of the eyes that’s closest to the temple. Lesions and damage to the optic chiasm can cause bitemporal hemianopia. The optic chiasm is located near the pituitary gland where the nerves from the left and right eyeballs meet and cross over one another to reach the opposite side of the brain.
Loss of vision occurs in one quadrant or portion of the visual field, and this usually depends on the part of the brain that’s damaged. The area that’s connected to the damaged portion of the brain will suffer either partial or complete hemianopia.
Superior hemianopia:Superior hemianopia is when loss of vision occurs in the upper visual field of either the left or right eye or both.
Inferior hemianopia:Inferior hemianopia is when loss of vision occurs in the lower visual field of either the left, right, or both eyes.
What causes hemianopia?
There are several different factors or injuries that can cause hemianopia including brain injuries, strokes that occur in certain parts of the brain, and physical head trauma.
As mentioned, while severe migraines can cause temporary hemianopia and adversely affect the patient’s vision, this symptom typically subsides on its own once the migraine pain is relieved.
However, there are more permanent and hazardous causes of permanent hemianopia.
Damage to certain parts of the brain such as blunt force trauma due to an accident or sports injuries accumulated over an extended period of time can lead to hemianopia in the visual fields of the eyes. These injuries can incur the growth of lesions or contusions on the brain over long periods of time, which can cause hemianopia in old age or even earlier on in life depending on the severity and frequency of the injuries.
As brain tumors begin to form and continue to grow over time, they can have the same effects as traumatic brain injuries. Eventually, the pressure and damage caused by the tumor can directly result in hemianopia in either one or both of the eyes.
Strokes typically occur as a result of insufficient supply of oxygen reaching the brain. Oxygen is important because it promotes healthy and stable cranial functions. The blockages happen for a number of reasons, the most common one being the formation of blood clots. Depending on the severity of the stroke, it could be fatal for the person who endures it. While survival is certainly preferable, it also means enduring various physical and mental ailments, including hemianopia.
What are the symptoms of hemianopia?
Hemianopia has a variety of signs and symptoms that are associated with it, including the following:
- Loss of peripheral vision on one or both sides of the face
- Loss of visual awareness
- Constantly bumping into people or objects on a regular basis
- Failing to notice objects or people on the side of the face where the hemianopia damage has occurred
- Inability to process entire sentences, phrases, or words when reading due to disturbed or interrupted visual patterns
- Visual hallucinations, as in seeing things that aren’t necessarily there such as certain lighting effects
In addition to the physical indicators of hemianopia, there are also a few psychological, emotional, cognitive, and even social repercussions. Many patients who suffer from hemianopia can become increasingly frustrated or frightened as their condition worsens because it can make mobility and attending social events extremely difficult. As a result, this loss of field vision can also have a negative effect on a person’s ability to live independently and a lot of patients may become gradually reclusive because they fear the outside world and enduring potential injuries.
Mounting irritation, aggravation, and stress also accompany hemianopia because people who suffer from it constantly think that people are bumping into them or objects are appearing out of nowhere. This can make it virtually impossible to function normally in crowded places. Part of the problem is that a lot of people don’t even realize that they have hemianopia until they’re officially diagnosed with it.
How is hemianopia diagnosed?
In order to accurately diagnose hemianopia, your optometrist will most likely send you to a specialist who will then conduct a series of tests on your vision. They’ll start off by asking you a series of questions with the intent of gaining a thorough and clear understanding of the symptoms you’re experiencing. You’ll also undergo a series of visual tests using a machine called a Humphrey Field Analyzer.
This machine tests the depth of vision in each eye individually. It flashes lights in each possible point of your vision including the upper left, lower left, upper right, lower right, and the center. All you have to do is press a button to indicate when you see the light. If the machine detects that you’ve missed the light multiple times in the same areas, it’ll determine that there may be blank patches within your visual field and this is an indication that you may have hemianopia.
Following this assessment, if it’s determined that you do have hemianopia, your doctor may then order a series of MRI tests to establish the initial cause of this condition, whether it was a brain injury, stroke, or a tumor.
How is hemianopia treated?
It’s important to note that while hemianopia treatments can be highly effective and rehabilitative, there’s no actual cure for this condition and you will have to continuously undergo various relief methods that can only stand to improve the condition and make it more manageable.
That said, the following is a list of treatment options for hemianopia. It’s up to your doctor to determine which one would be the most suitable for you depending on the type and severity of the hemianopia you have. In some cases, it might even be appropriate and useful to incorporate a combination of these treatments. Again, your doctor will typically use their own expertise and discretion in such cases.
Visual restoration therapy
This is provided by NovaVision and uses computerized software to help improve patients’ vision in half-hour increments where the patient is instructed to focus their gazes on a specified point and must move their head whenever they see a flash of light or other stimuli in their field of vision. This information is recorded by the computer and the treatment is adjusted with each session and progress of the patient.
Audio-Visual stimulation training
This is a multi-sensory visual training approach to attempting to improve the visual fields of people who suffer from hemianopia and it’s especially effective for treating homonymous hemianopia. It stimulates both the auditory and visual senses in an attempt to get them to work harmoniously with one another and improve the patient’s quality of life despite having this condition.
Optical visual span expanders
These are specialized sunglasses that are formulated specifically for each individual patient and their level of hemianopia. The sunglasses have prisms embedded in their lenses that can help enhance the patient’s vision and expand their field of vision while wearing them.
Explorative saccade training
Also referred to as scanning therapy, this technique tests the speed and correlation with which both eyes move from one focal point to another. The optometrist will observe as the patient’s eyes jet from one vertical or horizontal focal point to another and examine whether the eyes separate or move in unison. People who suffer from hemianopia are taught to incorporate this visual technique in their everyday lives to help them naturally expand their field of vision in every direction.
How does hemianopia effect everyday life?
Hemianopia can have a detrimental effect on a person’s everyday life if left untreated. Especially as people get older, they tend to become more reclusive due to this condition because they feel like burdens to their loved ones and everyone around them. People with diminished eyesight may have a hard time moving around without bumping into people or objects and because their line of vision is diminished as well, they most likely will have to surrender their driving privileges as well. This can make them feel like an even greater burden on their family and friends if they need to be driven everywhere or require the special assistance of a loved one or caregiver.
Hemianopia will undoubtedly have a strong impact on your everyday life, but that doesn’t mean it has to hold you back from being able to resume your regular activities or from doing the things you enjoy. By learning proper management and adaptation techniques, you can learn to live with and even conquer symptoms associated with hemianopia. If you’ve recently suffered a stroke, brain injury, or tumor and are noticing a vast decline in your vision, express these concerns to your doctor immediately so that they can start taking steps to administer a helpful treatment plan.
CORONA, Calif., May 3, 2016 /PRNewswire/ — In addition to being the fourth leading cause of death in the United States, strokes can lead to any number of life-changing disabilities. One of the most common side effects of the estimated 800,000 strokes that occur each year in the country is a loss of side vision (hemianopsia) of up to one-half to the right or the left. With May being both “Stroke Prevention Month,” as well as “Healthy Vision Month,” there is a new focus on the challenges patients with stroke-related hemianopsia face, as well as the hope that advanced Side Vision Awareness Glasses (SVAG) can provide.
“When individuals experience hemianopsia much more than just their side vision is reduced,” says Richard Shuldiner, OD, founder of The International Academy of Low Vision Specialists (IALVS), “Their quality of life diminishes, too.” So concerned about bumping into others or accidentally walking off a curb or into traffic, the condition can leave patients feeling insecure in unfamiliar surroundings. Some avoid going out altogether; others struggle to make it through the day. Though no treatment can actually restore the lost field of vision for these patients, Side Vision Awareness Glasses (SVAG) serve as optical field expansion devices that can increase patients’ viewing fields, improve their safety and enhance confidence. So effective, patients with custom-made SVAG typically experience an increase of about 15 degrees in side vision awareness immediately upon putting them on. The use of SVAG may even allow some patients to resume driving.
Developed by IALVS member Dr. Errol Rummel, Director of the Neuro-optometric Rehabilitation Clinic at the Bacharach Institute for Rehabilitation in Pomona, NJ, SVAG represents an important advancement over other devices that came before them. Crafted of lens materials known to minimize distortion, they are noticeably thinner. Also, there is no obvious line in front of the lens, no “thick button,” and no lens strip inserted through the front of the lens. The front of SVAG’s lenses is smooth and barely distinguishable from ordinary glasses.
More important than being better looking than previous devices designed to manage the condition, SVAG provides far-improved vision by offering the widest viewing area. Their vertical edge enables a person with hemianopsia to move their eyes just a few millimeters to access the SVAG area of the lens. Unlike devices that superimpose a narrow peripheral image over a person’s central vision, SVAG is easier for patients to use, as well as to learn to use. They’re also harder to break, because there is no glued seam splitting through the lens from front to back.
Patients with hemianopsia who are acutely aware of their side vision loss can often be trained to scan their eyes to compensate for their impairment, but for those who are unaware or inattentive to the condition, which doctors term “hemianopsia with neglect,” SVAG can go beyond increasing their field of vision—they can broaden their worlds.
In any case, a qualified low vision optometrist can help you determine whether Side Vision Awareness Glasses are right for you or a loved one. All members of The International Academy of Low Vision Specialists are low vision optometrists with extensive training and experience in assisting patients suffering from stroke-related hemianopsia. To locate a member near you, simply visit their website: www.ialvs.com or call 1-888-778-2030.
For more information, contact:
Tracy LeRoux, The Link Agency, Inc.
SOURCE International Academy of Low Vision Specialists
See the original video here: http://www.showme.com/sh/?h=xyvD3Gi Created by Dale Ledford, a college Biology, Human Anatomy, and Physiology instructor in Blountville, Tennessee.
The purpose of this education is to help you understand how to screen, refer and treat patients related to functional performance.
WE DO NOT DIAGNOSE!
Objectives for Today
■ Identify signs and symptoms that indicate a potential vision problem.
■ Identify the differences amongst the variety of vision problems that can occur
following a neurological event and how it impacts functional performance with
■ Identify how to accurately screen for potential vision problems and when to refer to
an eye specialist.
■ Identify therapeutic approaches used to treat and compensate for problems,
allowing for improved function.
[Case Study] Transcranial direct current stimulation (tDCS) combined with blindsight rehabilitation for the treatment of homonymous hemianopia: a report of two-cases – Full Text PDF
[Purpose] Homonymous hemianopia is one of the most common symptoms following neurologic damage leading to impairments of functional abilities and activities of daily living. There are two main types of restorative
rehabilitation in hemianopia: “border training” which involves exercising vision at the edge of the damaged visual field, and “blindsight training,” which is based on exercising the unconscious perceptual functions deep
inside the blind hemifield. Only border effects have been shown to be facilitated by transcranial direct current stimulation (tDCS). This pilot study represents the first attempt to associate the modulatory effects of tDCS over
the parieto-occipital cortex to blindsight treatment in the rehabilitation of the homonymous hemianopia.
[Subjects and Methods] Patients TA and MR both had chronic hemianopia. TA underwent blindsight treatment which was combined with tDCS followed by blindsight training alone. MR underwent the two training rounds in reverse order.
[Results] The patients showed better scores in clinical-instrumental, functional, and ecological assessments after tDCS combined with blindsight rehabilitation rather than rehabilitation alone. [Conclusion] In this two-case report parietal-occipital tDCS modulate the effects induced by blindsight treatment on hemianopia.
[Conclusion] In this two-case report parietal-occipital tDCS modulate the effects induced by blindsight treatment on hemianopia.