Topical Blog Week #8 (Due Wednesday)

Change blindness (CB)

Change blindness is a phenomenon in visual perception in which very large changes occurring in full view in a visual scene are not noticed. This topic is directed linked to chapter 7 in our text (pgs. 210-217)

After researching the subject of change blindness, I found that recently a number of studies have shown that under certain circumstances, very large changes can be made in a picture without people noticing them. What characterizes the experiments showing such "change blindness" in visual scenes is the fact that the changes are arranged to occur at the same time with some kind of extraneous, brief disruption in visual continuity, such as the large retinal disturbance produced by an eye saccade, a shift of the picture, a brief flicker, a "mud splash", an eye blink, or a film cut in a motion picture sequence (just examples). These phenomena are attracting an increasing amount of attention from experimental psychologists and from philosophers, because they suggest that humans' internal representation of the visual world is much smaller than they thought.

One of the first experiments on CB were done in the context of saccadic suppression by Bridgeman, Hendry & Stark (1975) and they found that large displacements of the entire visual field were not noticed if they occurred during saccadic eye movements.

That triggered interest in CB from McConkie & Currie (1996) where participants viewed visual scenes presented on a computer monitor, while their eye movements were being measured. The computer could make changes in the scene as a function of where the observer looked. For example, when the observer looked from the door of a house to the window, say, the window (or some other element of the scene such as the sky, or the car parked in front of the house) changed in some way: it could disappear, be replaced by a different element, change colour, change position, etc.

It was found that when the change occurred during an eye movement, surprisingly large changes could be made without the observers noticing them. Elements of the picture that occupied as much as a fifth of the picture area would not be seen.

At first, the explanation of the phenomenon was assumed to have something to do with the mechanisms the brain uses to combine information from successive eye fixations to form a unified view of the visual world. In particular, every time the eye moves, the retinal image shifts. Some mechanism in the brain may correct for such shifts in order to create a stable view of the world. However the mechanism could be imperfect and not take into account certain differences in the visual content across the shift, thereby explaining why changes made during saccades might sometimes go unnoticed.

From my research here are some theories of change blindness:
Currently accepted explanation of change blindness owes much to the work done in the 1960's and 70's showing how visual information is transferred via an attentional "bottleneck" to a very low capacity short term visual storage done by Gegenfurtner & Sperling in 1993.

Concluding with the explanation of change blindness involves two components: a component related to what is called "visual transients", and a component related to the way a scene is encoded in memory.

Visual transients are fast changes in luminance or color in the retinal image, such as would be produced by a sudden appearance or disappearance, or through motion of an element of the scene. It is known that such transients are detected in the first levels of the visual system, and that attention is automatically attracted to the location where they occur.
Under normal viewing conditions therefore, when a change occurs, it produces a visual transient which attracts attention to the change location. The transient thus provides information that a change has occurred, and it says where it occurred, but it does not provide information about what the change was.

In order for an observer to be able to determine what the change was, he or she will have had to have encoded into visual memory what was at the change location before the change occurred, and compare it to what is there after the change. (WOW!{me})

Lastly, and on a personal note, all this is completely and quite fascinating to me especially because I believe I suffer from change blindness. It took me a long time to recognize the differences, longer than most during my personal experiments.

http://wexler.free.fr/library/files/bridgeman%20%281975%29%20failure%20to%20detect%20displacement%20of%20the%20visual%20world%20during%20saccadic%20eye%20movements.pdf
- This website is shown to be the first real experiment linked to Change Blindness. It provided me with the knowledge and information needed to complete my blog on the topic from chapter 7.

http://www.gocognitive.net/demo/change-blindness & http://www.cogsci.uci.edu/~ddhoff/cb.html
- These two websites provided me with a real demo of the test that some psychologists use. Also, gave me actual insight of what it feels like to be a participant in an experiment.

http://www.ic.ucsc.edu/~bruceb/psyc123/ChangeBlindnesslab4.html
- This website provided me with the first resources that lead to further research on the subject of Change Blindness.

Terms: Change blindness, visual perception, psychologists, philosophers, eye, experiments, visual continuity, retinal, brain, visual field, test, resources, research, eye movement, experiment, participants, observers, perception, element, visual, color, retinal, image, subject and scene.

1a) State what your topic is.
My topic is visual-field defect.

1b) Discuss how the topic relates to the chapter.

Visual-field defect was talked about in Chapter 7. Visual-field defect is a portion of the visual field with no vision or with abnormal vision, typically resulting from damage to the visual nervous system. Brain damage that produces this deficit is actually pretty rare. A person who is unfortunate enough to lose this primary visual cortex in the right hemisphere will be blind on the opposite side of the visual space.

1c) Discuss why you are interested in it.

The reason I’m interested in this is because I think it’s a really sad but interesting problem. Not a lot caught my eye this chapter but I did think visual-field defect was interesting. I really had no idea that there was another visual problem that was so closely linked to blindness. I’m sure someone going through this after brain damage is at least thankful they can somewhat see. But I’m sure it’s still something extremely hard to deal with at the same time. I wanted to research more into how much someone with this can see, or what exactly they do see.

The visual field is the portion of the subject’s surroundings that can be seen at any one time. The normal extent of field of vision is 50 degrees superiorly, 60 nasally, 70 inferiorly, and 90 temporarily. A visual field defect is a loss of part of the usual field of vision, so it does not include blindness of either eye or both eyes. The lesion may be anywhere along the optic pathway; retina to occipital cortex.

Visual field can be lost due to age-related macular degeneration, optic neuropathy, leber’s optic atrophy, macular holes, cone dystrophies, and different conditions like Best’s disease, Stargardt’s disease, and achromatopsia. Peripheral field loss occurs with glaucoma, retinal detachment, retinitis pigmentosa, and chorioretinitis.

Visual acuity tests the eye’s greatest power of resolution whereas visual field testing measures the peripheral sensitivity. The image is projected on to the retina upside down and inverted. A lesion on the top right of the retina or the pathway beyond will cause a defect in the bottom left of the visual field. Assessing for visual field defects can be looked at during screening tests which include confrontational visual field testing or with the use of an Amsler grid. Or with quantitative measurements using manual or automated perimetry.

Scotoma is another related visual field defect. It is a defect surrounded by normal visual field. Relative scotoma is an area where objects of low luminance cannot be seen but larger or brighter ones can. Absolute scotoma is where nothing can be seen at all within the area. Hemianopia is a binocular visual defect in each eye’s hemifield. Bitemporal hemianopia is where the two halves lost are on the outside of each eye’s peripheral vision, effectively creating central visual tunnel.

Homonymous hemianopia is where the two halves lost are on the corresponding area of the visual field in both eyes, either the left or the right half of the visual field. Altitudinal hemianopia is the dividing line between loss and sight being horizontal rather than vertical with visual loss either above or below the line. Quadrantanopia is an incomplete hemianopia referring to a quarter of the visual field loss. Sectoral defect is also an incomplete hemianopia.

Confrontation visual field testing is the main method of assessing visual field loss. It is a qualitative measurement but is the best starting point. Traditionally a hatpin has been used to define the visual field. A red or white head is used and it may be moved across the visual field to ascertain where it disappears and hence to define a scotoma. The amsler grid testing is also a good testing method. This asses the central 10 degree visual field. It detects central and paracentral scotomas.

Retinal detachment is related to visual-field defects. Retinal detachment and occlusion of blood vessels at a level smaller than the central retinal give defects with boundaries in the horizontal meridian. It tends to be fairly rapid in onset. It may follow trauma or there may be predisposing factors. It may be preceded by floaters and flashes before what the person may describe as a curtain coming across the visual field. A crescentric red or orange slip or detachment may be apparent at the periphery of the retina. Central retinal artery occlusion tends to be a sudden and complete loss of vision in one eye but if the occlusion is at the level of one of the four arteries to the retina, there will be loss of just a quadrant of field.

Terms: visual-field defect, nervous system, visual, vision, abnormal vision, primary visual cortex, blind, optic pathway, retina, occipital cortex, macular degeneration, optic neuropathy, leber’s optic atrophy, macular holes, cone dystrophies, acuity tests, resolution, peripheral, Amsler grid, perimetry, relative scotoma, luminance, absolute scotoma, hemianopia, quadrantanopia, confrontational visual field testing, retinal detachment, horizontal meridian.

URL: http://www.patient.co.uk/doctor/visual-field-defects

URL: http://almostadoctor.co.uk/content/systems/ophthalmology/visual-field-defects

URL: http://www.britannica.com/EBchecked/topic/630842/visual-field-defect

The reason I chose these websites is because they talked about the causes and effects of visual-field defects. They all gave me a better understanding of it. The second website gave me a really good diagram of the eyes and how the defects are different from “normal” eyes.

The topic I chose to further research was change blindness. Change blindness relates to chapter seven in many different ways. Chapter seven talks about the visual system and the way we notice and see things that grab our attention. Chapter seven also talks about how at times our eyes fail to notice change in different scenes. Change blindness is that failure to notice a change between two scenes. I find this topic interesting because I always thought I was good at picking out the differences between two scenes, meaning that I always notice the small details that changed. After reading about change blindness in the book, I wanted to further research it. Sensation and perception has got me interested in so many different subjects but I believe that change blindness is one of the more interesting subjects I have researched.

According to Wikipedia, “change blindness is a surprising perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it.” This is close to what I defined change blindness as before but I like how this definition uses the particular word ‘phenomenon’. To me, all things are a phenomenon. How is it that some things are understood but some things we just can’t seem to figure out? Research on change blindness developed from interest in the phenomena of eye movements and working memory. Sometimes people are really good at remembering things but when it comes to recalling the smaller details it automatically becomes a challenge. Sometimes change blindness can be confused with inattentional blindness. Inattentional blindness is defined as an individual failing to recognize an unexpected stimulus in plain sight. Although both of these terms involve failing to recognize something, change blindness involves two separate scenes changing and inattentional blindness involves one scene adding a stimulus.

There are a few factors that I want to talk about that influence change blindness. Age is one of these factors and there have been studies over this particular influence. These studies concluded that older individuals were slower to detect the changes in an experiment than younger individuals who took the same test. This is also true when different age groups were asked to make a decision of a change blindness paradigm used at an intersection. The older individuals failed to make the right decision more often than the younger individuals. Another factor influencing change blindness is object presentation. This is the way in which objects appear. Even when there is not a delay between the original image or scene and the altered image or scene change blindness can occur but only if the change forces the viewer to redefine the objects. Both the appearance of a new object and the forthcoming of an object are more resistant to change blindness than the withdrawing of an object.

There are also some practical implications relating to the phenomenon of change blindness. Eyewitness testimony and the inaccuracy of it could have something to do with change blindness. Witnesses are rarely able to detect a change in the criminal’s identity unless first intending to remember the incident in question which in turn can lead to inaccuracy in identifying these criminals. In court, change blindness is starting to be questioned so we can weed out mistaken eyewitness identification and wrongful conviction.
Driving ability is another practical implication that relates to change blindness. Like I stated earlier, older individuals are slower to detect changes in scenes than younger individuals. When you are driving, the location and relevance of the changes happening can have an effect on what is noticed while driving. We can obviously see better and have a faster reaction time when we are in the center of our visual field instead of using our peripherals. This leads to the conclusion that drivers are able to recognize relevant changes more so than irrelevant changes. Researching the effects of change blindness could lead to answering some questions as to why car accidents happen. When I was reading about this I was thinking to myself about how cool different things we study relate to such intense and interesting things like these.

Change blindness is an interesting subject and sometimes hard to study because how do we know that the answers we are coming up with are accurate? Sometimes past experiences and expectations can have an effect on the way that we see things from scene to scene. Some people know that changes that occur in real life are usually easy to see so it is almost like they expected the change which makes it easier to detect. When we know that something is about to happen that means it has our attention. When something has our attention, we are more apt to notice things relative to that situation rather than something that doesn’t have your attention at that time.

There have been different studies done on change blindness and there was one particular study done by Simons and Levin (1998) that stood out to me involving a human being as the changing stimulus. The participants involved had to start having a conversation with a stranger. After so long, the stranger was replaced with a different stranger during a brief interruption of a large object coming between them. What I found interesting was that the participants did not realize that the stranger they had been conversing with had changed. I found this study interesting because this leads into the ability to recognize faces also known as prosopagnosia. We studied this in previous chapters so I found it interesting how this can relate back to that.
Terms: Change blindness, sensation, perception, inattentional blindness, attention, visual system, visual field.

http://en.wikipedia.org/wiki/Change_blindness - I like to use Wikipedia because there is usually a ton of information on it that helps me better understand the subject that I am researching. There was a ton of information on change blindness and it was interesting to read about it.

http://psychology.about.com/od/cognitivepsychology/f/change-blindness.htm - I liked this source because it shared a lot of research studies that have been done and it was interesting to read about them. Reading about these made me want to research more studies that have been done.

http://transcendsense.com/change-blindness-and-inattentional-blindness/ - I liked this source for research because it included a helpful video. Sometimes when I am told something rather than reading it, the information clicks a little better.

In chapter seven, we learn several curious phenomena surrounding attention and scene perception. These topics are closely related because many times our perception depends on where our attention has been focused. To review, inattentional blindness is a failure to notice unexpected events in the scene. This is particularly likely to occur when the viewer is engaged in a difficult monitoring task, if the viewer is not particularly attending the unexpected event, or if the unexpected event is not sufficiently similar to the attended subject. For example, in Simons and Chabris’ well-known ‘gorilla-suit’ study (1999), basketball players were dressed in black and white, and participants were asked to count how many times the ball was moved on the floor, which we call a monitoring task. Here, the players are the attended subject. In separate groups, Simons and Chabris introduced an unexpected event in the form of a person in a gorilla suit or a woman in plain pale clothing and an umbrella. Overall, participants were more likely to notice the woman with the umbrella than the guy in the gorilla suit. However, when attending players dressed in black, participants were more likely to notice the guy in the gorilla suit. When attending players in white, no difference was seen between the gorilla and the woman. We can conclude that attending to the black jerseys had participants on the lookout for individuals dressed in black, which made them more likely to notice the gorilla. These findings indicate similarity to the attended object, in this case color, and facilitates noticing the unexpected event.
An interesting paradox of the visual system is that we sometimes do notice unexpected events. This is explained by the von Restorff effect. The von Restorff effect contradicts inattentional blindness by saying we are more likely to remember unexpected events. This paradox has been the subject of many studies since Simons and Chabris’ gorilla suit study. In subsequent studies, researchers have built on Simons and Chabris’ original study of inattentional blindness, determining stimuli are more likely to be noticed and remembered if they are extremely arousing. Arousal influenced memory to a higher degree than did distinctiveness. This is an interesting finding; to improve memory, objects or words should be arousing. In the context of class, conversation, or almost anything in real life, we will be more likely to attend and remember if the object of our attention is arousing. Memory also depends a great deal on context. When using a comparison list, the isolation effect works as a combination function of two factors, distinctiveness and relationship of the target to other words in the list. This is because our attentional resources are primarily consumed with finding the target. When the target is sufficiently different from the rest of the items in the list, it is more easily identified. Therefore, leftover attentional resources can be utilized for encoding.
Given the findings of these studies, we can infer the paradox is really only superficial. Subsequent to the gorilla-suit study (1999), visual studies of inattentional blindness have only expanded on the phenomena behind inattentional blindness. Many factors contribute to attention or memory of the attended object which interact in complex ways. If we could determine the arousal and distinctiveness of the target in its context, we would have better chances of predicting inattentional blindness. However, these factors are subjective and somewhat difficult to measure. At present, not much research exists (or none that I could find) to examine these.
Inattentional blindness, attention, scene perception, monitoring task, von Restorff effect, encoding

The original basketball/gorilla study reported in the chapter:
http://www.drjoebio.com/uploads/1/8/1/3/1813500/gorrila_in_our_midst.pdf
Explores factors that contribute to inattentional blindness, including difficulty of monitoring task and similarity to subject of focus, among others.
http://eds.a.ebscohost.com/eds/pdfviewer/pdfviewer?sid=e502bd48-ef8f-46cd-bc31-fb4e8adeda79%40sessionmgr4004&vid=12&hid=4111
Inattentional Blindness Von Restorff Paradox
http://eds.a.ebscohost.com/eds/pdfviewer/pdfviewer?vid=3&sid=e502bd48-ef8f-46cd-bc31-fb4e8adeda79%40sessionmgr4004&hid=4111

The topic I chose to do further research on was Balint's syndrome. This relates to the chapter, because it is perceptual disorder that is discussed briefly in the chapter. I found it interesting, because I can't imagine what it would be like to live with such a disorder.
Balint's syndrome is an uncommon trio of severe neuropsychological impairments that are not entirely understood. These three are the inability to perceive the visual field as a whole (simultanagnosia), difficulty in fixating the eyes (oculomotor apraxia), and the inability to move the hand to a specific object by using vision (optic ataxia). This syndrome occurs mostly as an acute onset after two or more strokes that happen in about the same place in the brain. The fact that the strokes must happen in about the same place within the brain is what makes this such a rare disorder. Someone suffering from Balint's Syndrome are not able to perceive and focus on more than one object at a time. When a spoon is held up for the patient to see, they can usually identify it as a spoon. However, when a second object, like a comb, is introduced next to the spoon, the patient will either not see the comb or will no longer see the spoon and only the comb. As the two items are moved back and forth in space, the patient will tend to go back and forth on which one they can see, but they are never able to see both at the same time. When this was done with one particular individual and he had been focusing on the two objects for long enough, he no longer saw either one and could only see the blackboard that was several feet behind in the background. When this individual was presented with just the spoon and asked to reach out and touch it, he had a great deal of difficulty. He would often try to grab several inches to the side of where the spoon actually was, almost as if he had double vision. When the spoon was shaken, the patient was able to grab it more easily, but still with some degree of difficulty. However, as soon as the spoon was held still again, he reverted to not being able to grab it. Partly because of its symptoms and partly due to its rarity, Balint's Syndrome is often misdiagnosed as blindness, psychosis, or dementia. The symptoms are generally first noticed by the therapists providing rehabilitation following brain lesions. Because most practitioners are not familiar with the disorder, the symptoms are often mistaken for something else, such as the previously mentioned misdiagnoses. Treatment for Balint's Syndrome are very few in number, and a large percentage of those few that exist are criticized as being poorly developed and evaluated. There are currently three main approaches to rehabilitation for perceptual deficits like Balint's Syndrome. The first is the adaptive, or functional, approach. This involves functional tasks utilizing the patient's strengths and abilities, helping them to compensate for problems or altering the environment to lessen their disabilities. Of the three, this is the most popular rehabilitation approach. The second strategy is the remedial approach. This involves restoration of the damaged central nervous system by training in perceptual skills, which may be generalized across all activities of daily living. This could be achieved through things such as tabletop activities or sensorimotor exercises. The third approach is the multicontext approach. This is based on the fact that learning is not automatically transferred from one situation to another. It involves practicing of a targeted strategy in multiple environments with varied tasks and movement demands, and it also incorporates self-awareness tasks. There are some, however, that question the validity of Balint's Syndrome as a whole. They say that the components in the syndrome's trio of symptoms each may represent a variety of combined defects. "Because Balint's Syndrome is not common and is difficult to assess with standard clinical tools, the literature is dominated by case reports and confounded by case selection bias, non-uniform application of operational definitions, inadequate study of basic vision, poor lesion localization, and failure to distinguish between deficits in the acute and chronic phases of recovery."

https://www.youtube.com/watch?v=4odhSq46vtU - I used this source, because it showed a visual example of a patient suffering from Balint's Syndrome and is difficulty in object perception.

http://en.wikipedia.org/wiki/B%C3%A1lint's_syndrome - I used this source, because it provided a strong base of information on the topic.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1737727/ - I used this source, because it was a more specific publication about the possible causes of the disorder, and it was from a very reputable source.

Terms: Balint's Syndrome, Neuropsychological Impairment, Simultanagnosia, Oculomotor Apraxia, Optic Ataxia, Perceive, Adaptive, Central Nervous System, Perceptual Skills, Sensorimotor, Remedial, Multicontext

1. A) Visual field defect
B) Visual field defect talks about how a this deficiency affects how much a person is able to see in their normal field of view.
C) I was interested to find out if there were treatments, but there were not many. I was surprised to find out that a person will eventually get used to this.
2. Visual field defect is a blind spot or area in the field of vision in either one of both of the eyes. It is permanent but in few cases it can be temporary or shifting. Sometimes it can also occur every so often. Usually that will only happen if a person is experiencing a migraine. Visual field defect can be central of peripheral. If it is central then it would be an optic disc of nerve problem. If it peripheral then it is along the visual pathways from the optic chiasm.
If a person if being tested then it is important to test both of the eyes separately because both of the eyes may overlap and the visual field defect may not be found. When a person is tested there will be many questions about the history of the defect. These questions include where is the field of loss, did it happen suddenly or slowly, does it affect both eyes or just one, and is it a black spot or a blur? There are many ways to a assess for visual field defect. A person could do a screening test, quantitative measurements, amsler grid testing, or in a GP surgery.
There have been multiple causes found. These causes are glaucoma, vascular disease, tomours, retinal disease, hereditary disease, optic neuritis, inflammatory processes, nutritional deficiencies, toxins, drugs, or damage to the retina. Certain patterns can help establish the underlying cause. Generalized constriction can be caused from glaucoma, retinitis pigmentosa, nysteria, or chronic high intracranial pressure. Causes of central field loss can be caused by age-related mascular degeneration, optic neuropathy, Leber's optic atrophy, mascular holes, and cone dytrophies. Causes of peripheral field loss can be from glaucoma, retinal detachment, retinis pigmentosa, or chorioretinitis.
For treatment a doctor can only help so much depending on how the person got visual field defect. There is an oral medication. The person will eventually become used to this but can only perform certain tasks. Fortunatly they can make up the visual loss by the way they look at things.
Terms: Visual field defect, glaucoma, retina, generalized constriction, retinis pigmentosa, nysteria, central field,optic neuropathy, peripheral field, optic chiasm.
http://www.britannica.com/EBchecked/topic/630842/visual-field-defect
This website discusses in great detail the variety of different causes.
http://www.patient.co.uk/doctor/visual-field-defects
This website discusses and helpful explaining the testing and assessments for visual field defect.
http://www.newhealthguide.org/Visual-Field-Defects.html
This website was helpful because it explained the different treatments, though there were not many.

For this week’s assignment, I chose to do more research on Balint Syndrome. Balint Syndrome is defined as an uncommon and incompletely understood triad of severe neuropsychological impairments: inability to perceive the visual field as a whole (simultanagnosia), difficulty in fixating the eyes (oculomotor apraxia), and inability to move the hand to a specific object by using vision (optic ataxia). This topic fits with our current chapter and also with the course because it is yet another disorder than can affect our sensation and/or perception of the world around us.

Starting this research and trying to find just a specific definition of this syndrome was quite exhausting. Through the websites I found and read the definitions, basically the part that caught my eye was simultagnosia, the inability to take in the entirety of a picture while instead seeing only parts of the whole. For example, when shown a picture of a house, someone with simultagnosia could only see a window, a door, a wall, and so on, but not the entire house. The disorder usually results from damage to both parietal lobes, which help us know where we, and other objects, are in space. When symptoms come on suddenly, they're likely due to stroke; but other disorders such as tumors, and even neurodegenerative diseases such as Alzheimer’s, can also sometimes lead to Balint’s syndrome. Someone with Balint’s syndrome can’t judge her location relative to things around her by sight: she must depend on other senses to guide her. She may, for example, need to keep a hand on the sink in order to know where it is in the bathroom. And she may need to put toothpaste into her mouth, rather than on the toothbrush. She may not be able to use utensils at the table, since she can’t use vision to aim her hand to pick up a fork or a spoon. It may be impossible for people with Balint’s syndrome to read, since simultagnosia means she may only see one letter at a time, and may not be able to put that letter into the context of a word or sentence.

On a positive note, there are some therapies out there to help with this syndrome. Occupational therapy offers some means for people with Balint’s syndrome to recover a degree of independence. While different approaches have been suggested, no one approach is clearly the best, and it may be helpful to consider using techniques normally used to assist the blind. For example, therapists may suggest ways to use other senses to replace damaged perception. Books on tape can be used instead of usual reading material, and a radio may replace television viewing. In order to get this kind of assistance, though, both the patient and the medical professional must be aware of the problem in the first place. Because Balint’s syndrome is relatively uncommon, the symptoms are often missed. Knowing that visual disturbances may not always be a problem with the eyes, but may also result from trouble with the brain, is a good start.

References:

http://en.wikipedia.org/wiki/Bálint's_syndrome I chose this website because I searched many other sites for just a definition of Balint’s Syndrome. I never came across a formal or concrete definition. I know Wikipedia is user updated, but this website was a definition a lay person could somewhat understand.

http://psy2.fau.edu/~rosselli/NeuroLab/pdfs/rehabilitation.pdf I chose this website because it had a case study report in it. There was also more therapies listed in this article.

https://www.youtube.com/watch?v=4odhSq46vtU I chose to include a YouTube video of this syndrome because many of us who have read about this topic, probably are curious (as I was) to see what this was really like for someone.

TERMS: Balint Syndrome, visual field, simultanagnosia, oculomotor apraxia, optic ataxia, parietal lobe, neurodegenerative diseases, perception, sensation,

1a) Balint syndrome and simultagnosia

1b) Balint syndrome and simultagnosia were vocabulary terms from chapter 7 and are brought up in a few paragraphs.

1c) Balint syndrome and simultagnosia was interesting just because I tried to imagine what a person with balint syndrome might view the world. Humans naturally are curious about things that are different than what they have, so I am very interested in this abnormality from the chapter.

2) Balint syndrome happens when a person has bilateral lesions of the partial lobes within the brain. It is an odd condition and does not happen very often. Balint syndrome has three major symptoms. The first is spatial localization abilities are greatly reduced. This results in a patient having a very hard time trying to reach toward on object near them or grab something when it is trying to be handed to them. The second symptom is patients with this disorder do not move their eyes as much as a person without does. They tend to have a more fixed gaze. The last symptom of balint syndrome is that they behave as though they can only see one object at a time. This deficit seems like an extreme form of extinction or neglect that when focusing on one object, all other surrounding objects are eliminated in doing so. The inability to perceive more than one object at a time is referred to as simultagnosia.

Balint's syndrome occurs most often with a severe onset as a consequence of two or more strokes at more or less the same place in each hemisphere of the brain. Therefore, it occurs rarely but makes it harder for us to really study and understand it further. The most frequent cause of complete balint's syndrome is said by some to be sudden and severe hypotension. This then results in bilateral border zone infarction in the occipital-parietal region. In even more rare cases of progressive balint's syndrome have been found in degenerative disorders such as Alzheimer's disease or certain other traumatic brain injuries at the border of the parietal and the occipital lobes of the brain.
Lack of awareness of the syndrome may lead to misdiagnosis of the disease and is often diagnosed in different disorders such as blindness, psychosis, or dementia. Symptoms of balint's syndrome are most likely to be noticed first by therapists providing rehabilitation following brain lesions and surgery. This becomes a problem due to the shortage of practitioners that have familiarity with the syndrome. The symptoms are often explained away incorrectly without being considered as a possibility and followed by medical confirmation of clinical and neurological findings.

As far as treatment options for balint syndrome there are three approaches to rehabilitation of perceptual deficits that are used with other similar disorders. The first is the adaptive approach. The adaptive approach involves functional tasks utilizing the person’s current strengths and abilities. This helps them to compensate for problems or altering the environment to lessen their disabilities. This is the most popular approach for balint syndrome. Another approach is the remedial approach. In this approach, restoration of the damaged CNS is fixed by training in the perceptual skills. This may be generalized across all activities of daily living. This could be achieved by tabletop activities or sensorimotor exercises. The final approach is the multi-context approach. This approach is based on the fact that learning is not automatically transferred from one situation to another. This involves practicing of a targeted strategy in a multiple environment with varied tasks and movement demands, and it incorporates self-awareness tasks. When dealing with an actual balint syndrome diagnosed patient they may use a combination of these three approaches to try and correct the disabilities though not very much success has been shown yet. While they cannot completely fix the syndrome, they can still train other parts of the brain to function better in order to complete everyday tasks that are difficult to do with this disease. Most of the information that is currently available is from case studies on balint syndrome.

Simultagnosia, as stated previously, is a rare neurological disorder characterized by the inability of an individual to perceive more than a single object at a time. This type of visual attention problem is one of three major components of balint syndrome. Simultagnosia can be divided into two different categories dorsal and ventral. Ventral occipital-temporal lesions cause a mild form of the disorder. Ventral results from damage to the left inferior occipital-temporal junction. Ventral simultagnosia patients are able to see several objects at once, but their recognition of objects is limited to one object at a time. Thus, individuals with ventral simultagnosia symptoms are capable of navigating through a room without bumping into things. Dorsal occipital-parietal lesions cause a more severe form of the disorder. This is when there are bilateral lesions to the junction between the parietal and occipital lobes. With dorsal perception is limited to a single object without awareness of the presence of other stimuli. This can cause a patient to collide with various objects in a room being unaware of them. Also, objects in motion appear more difficult to see.

Terms: Balint syndrome, simultagnosia, ventral, dorsal, occipital-parietal lobes, motion, rehabilitation, adaptive approach, remedial approach, multi-context approach

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1737281/pdf/v070p00416.pdf This is a section of an article going over the different treatment options currently available for balint syndrome.

http://vectors.usc.edu/issues/4/malperception/simultanagnosia.html this site explains in better detail dorsal simultagnosia and even has an activity to try to show what it may be like to have it.

http://informahealthcare.com/doi/abs/10.3109/02699052.2011.585506 This is a case report on balint syndrome that goes into rehabilitation and symptoms of the disorder

http://www.medscape.com/viewarticle/410860_5 This article goes into more depth on the types of simultagnosia along with a better explanation of what causes the disorder.

I chose the topic of inattentional blindness because I find it so fascinating that as a parent I can spot lie from a teenager a mile away but miss the most obvious of things in a video or television program. I think I am particularly susceptible to intentional blindness. I am constantly missing things and my husband will ask if I saw a person at a function and I will say no and he is flabbergasted because the person was there and I walked right by her. This type of scenario happens frequently. I wondered if there was a connection between this and ADD but I was not able to find very much that would support a connection. Perhaps it happens more frequently? I am not sure.
What I did find is that inattentional blindness serves a purpose. It helps us when we are focusing on something so that we are not distracted by all that is going on around us. This phenomenon is when we don’t see something very obvious that does not fit with a particular scene that we are concentrating on at the moment. The term was coined by two psychologists, Daniel Simons and Christopher Chabris at Harvard in the early 1990’s. Their research is based on the study of selective looking procedure that was introduced by psychologist Ulric Neisser at Cornell University. Some researchers have speculated that this is a form of amnesia that we in fact recognize the oddity but simply forget it very quickly. Although it is still up for debate, most of the information I read suggests that the majority of researchers believe that we simply don’t observe some unexpected things when our focus is fixated on a specific task. It is important to understand this because it helps us to realize that although we can be at the location of an event there is the possibility we could miss something very obvious.
One real world involved a very serious case with the Boston Police department in 1995. The officers received a call of a officer who had been shot. A car chase ensues and eventually several officers leave their cars to chase the suspect on foot. Two officers mistake an undercover officer for the suspect in the darkness and begin to beat him. As this is occurring anther officer named Conley ran past in pursuit of the suspect and didn’t stop to help the undercover officer. Conley’s claim was that he was so focused on the pursuit he did not notice the two officers beating the undercover officer. Conley admitted that he had been right in the area but that he had not seen anything. He repeated over and over that he couldn’t believe he didn’t see the commotion and that he wished he had. As it turns out no one else could believe it either and he was convicted of perjury and lost his position on the force. It was eventually overturned but because the state withheld evidence and he had already lost his job. Since that time there have been several studies and tests that show how we can so easily miss the obvious.
I watched several videos that tested the inattentional blindness. I did see the inserted object in one case but missed it in the others. In my very first Intro to psych class I missed the gorilla on the basketball court. I’ve watched it several times since and each time I am so flabbergasted that I ever missed the gorilla the first time, it now seems so obvious. However, I did find that I am not alone. Inattentive blindness happens to all of us, no matter our intelligence. This has been tested on airline pilots who missed things brought in on screens when they were focusing on other issues. A group of twenty-four radiologists who were given 239 frames of a chest x-ray and told to identify cancer in them. Five frames in a row contained an image of a gorilla. Although they are highly trained to examine the images twenty of the radiologists did not see the image of the gorilla. The researchers used eye tracking devices that showed that the doctors had looked right at the gorilla. So although they can regularly detect cancer modules that are much smaller than the added image they did not see the gorilla because they simply weren’t looking for it and didn’t expect it.

Experts believe the reason we are so surprised by inattentional blindness is because for the most part we don’t encounter it in our daily lives. In most cases the world is pretty stable, what we expect should be in a location is and there are few unexpected surprises. For instance we rarely have a gorilla running out on a basketball court, or a picture of one on an x-ray of a lung.
Terms: inattentional blindness, observe, focus, perceive, observe

https://www.youtube.com/watch?v=wdVXco6YDgg
Video of the radiologists
http://www.apa.org/monitor/apr01/blindness.aspx
Explanation, history and examples of inattentional blindness
http://www.scholarpedia.org/article/Inattentional_blindness
Another page with information on inattentional blindness and some other explanations
http://www.npr.org/2011/06/20/137086464/why-seeing-the-unexpected-is-often-not-believing
Story of the Boston Police Officer
https://www.youtube.com/watch?v=IZq-5i9PetE
The video where I did see the spider

(1a) Change Blindness

(1b) Change blindness relates to the chapter because the book discusses how it is hard for us to tell differences or change in two images or two scenes.

(1c) I was interested in this topic because I am so focused on calling myself a good multi-tasker, which in turn this chapter provides information to tell me that my attention does not have the span or ability to be a good multi-tasker. I can do many tasks at one time, but me remembering what I did and paying attention to those different tasks may be difficult.

(2) Change blindness is a perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it once so ever. Human attention has its limitations, one of these limitations is that people have a poor ability to detect changes. Change blindness has become a highly researched topic of interest, some even say it could provided important implications in eyewitness testimony and distractions while driving. Research today has been focusing on an abundance of topics, change detection was one of them. Individuals notice a change faster when required to detect changes in facial features than when required to detect changes in images of houses. Mental processing in change blindness relates to the increased brain activity in the parietal- occipital regions prior to the emergence of a change in a change blindness task. Another topic of research related to lucid dreaming, lucid dreaming occurs when one realizes that the events experienced within a dream are bizarre and would not occur in one's waking life. Inability to notice the bizarre nature of this dream is coined as an example of change blindness. Change blindness in teams has also been researched, teams working together notice changes in an image when assistance is present.

The detail dispersed among us when we look out at the world is extremely vast and available to us. But of the vast amount of detail, you would be surprised that we actually remember very little about a scene that we have just looked at. Ron Rensink and his colleagues investigate this phenomenon using a flicker paradigm, observers see a visual scene that flickers on and off. During this flicker scene, something of some sort in the scene changes. An object may move and reposition itself to another position, the object may change color, or it could just vanish. Experimenters like Rensink have found that participants are very poor at detecting these obvious changes. Detecting changes in a scene for example is hard to notice, magicians use sleight of hand to distract our attention away somewhere else while they perform a card trick. The flicker paradigm seems to be the best of the best when analyzing change blindness, the reason being is because it provides quick feedback and implementing the procedure is so easy and understandable.

The role of attention and how it operates in neuronal processing is a topic that has gone unresolved. The main focus of attention in individuals is to maintain a very minimum degree of visual awareness with which they can detect and discriminate classes of information at little or no cost to the central attentional processing circuit. What was found in a study was that attention tends to pool opposite of a cued location. Attention then is said to be object centered compared to location centered since visual awareness and attention is pooled away due to the smallest amount of peripheral cue obstruction. Experimenters expressed that mapping out attention in regards to studies done in change blindness will provide the best information.

(3) Terms : change blindness, attention, cue, parietal lobe, selective attention, visual awareness, flicker paradigm, change detection

(4) http://en.wikipedia.org/wiki/Change_blindness
This source has provided me with information I used to present a defined and accurate definition of change blindness and the research being done now a days to examine it.

http://nivea.psycho.univ-paris5.fr/ECS/ECS-CB.html
This source provided credible information that I used to describe experimental work done in regards to change blindness. I used Rensink and his flicker paradigm because it is the easiest to implement, and understand. While it also provided the most accurate results

http://mapageweb.umontreal.ca/gosselif/labogo/tse.pdf
This source provided information that I used to show the importance of mapping out visual attention with change blindness. This will provide the best information in regards to this new method of direction in future studies.