Prosopagnosia.

Discussion in 'Human Science' started by Enmos, May 21, 2008.

  1. Enmos Valued Senior Member

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    Can prosopagnosia be linked to dyslexia in some cases ?
    I have a friend who is dyslexic and has difficulty recognizing new faces.
    I wondered whether or not the two can be linked.
    Admittedly, difficulty recognizing new faces may not immediately count as prosopagnosia but there are obviously similarities between the two.

    To what extent can difficulties in recognizing new faces be said to fall within normal parameters ?
     
    Last edited: May 21, 2008
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  3. Enmos Valued Senior Member

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    No one ?
     
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  5. francois Schwat? Registered Senior Member

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    I don't know that dyslexics are more prone to face blindness. Unless there's any special reason to suppose there's a connection, there probably isn't one. It's just a coincidence that your friend has dyslexia and prosopagnosia. Supposedly prosopagnosia is usually caused by brain injury, although it is sometimes caused by a natural faulty wiring of the brain. In that case, it's congenital.

    It might be possible that some brain injury caused both or that some developmental instability caused his brain to develop abnormally and therefore cause both conditions.
     
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  7. Enmos Valued Senior Member

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    Nah, no injuries. I just see a similarity between the two conditions and wondered if there was a connection.
    By the way, I am not saying that he has prosopagnosia.. but he is very bad at recognizing new faces.
    For instance in a movie. He continuously does not recognize characters that already made several appearances. Or thinks unknown characters are familiar ones..
     
    Last edited: May 21, 2008
  8. francois Schwat? Registered Senior Member

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    It sounds like he has it a little bit. By this definition a person who has an extremely short memory and that short memory means he can't remember faces or names, then he would still have prosopagnosia, by the simple virtue of having a really bad memory in general.

    You said that you see a similarity between the conditions. Want to elaborate?
     
  9. Enmos Valued Senior Member

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    Dyslexia is a difficulty recognizing words right ?
    Dyslexics have to read letter by letter.
    The letters of a word make up a specific pattern that dyslexics fail to recognize.

    Faces consist of patterns as well.
    People with prosopagnosia have to remember specific traits, like scars for example, to recognize someone.
    Much in the same way dyslexics have to read a word letter by letter.

    This is the similarity I see.
    It is however not based on anything but my own thoughts (Ok, not completely. The facts are sound.).
     
    Last edited: May 21, 2008
  10. francois Schwat? Registered Senior Member

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    Ahhh, I see. That's a good insight.

    Dyslexia and prosopagnosia are both examples of a failure to "chunk," as psychologists put it. The ability to encode and decode recursive patterns, like the lines and curves which make up letters and words and then paragraphs and then chapters, and so on. Like the lines and curves that make up facial organs, which then make up an entire face.
     
  11. Enmos Valued Senior Member

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    Yep, I wondered whether or not both conditions could be linked to the same cause or a similar cause.

    Although the processes take place in different areas of the brain there might be a genetic or developmental underlying cause for both of the conditions.

    I could not find anything on it on the internet, so I thought I'd ask here

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  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I suffer from mild versions of both. I am not much in agreement with the explanation francois offers, but it could be part of the problem. I think it also, ironically, may be related to being very attentive to details. (Anyone familiar with my typically long carefully qualified post knows I surfer from that too.)

    Recognition of faces is an automatic process. Perhaps consciously noticing the details is a distraction which interferes with this automatic recognition process. Sort of like when you consciously try to remember something you know you know, it often makes it harder to remember but when you stop trying the automatic recall process may deliver the desired item to you. Or consciously trying to ride a bicycle will insure that you cannot. Most of what we repeatedly do is automated.

    I had to ask my first wife which of several girls dancing on a stage was my daughter, if there were many wearing the same dresses etc. When my current Brazilian wife and I go grocery shopping and separate to speed the process, I always try to remember what color her clothes are. If I fail to do this, it is hard to find her when I need new “assigned” items to go and find.

    When posting here I must edit several times after the spell checker has run to catch correctly spelled but not intended words. It very strange, but I cannot see them as wrong when I am typing. I read them to be the intended word, but after they are posted and part of a new layout (not in this little box) they are much easier to see as they really are. Often, since I am in "edit mode" I notice that my post lacks some qualification or detail, so it grows. You can see this when someone quotes me in reply before I have finished my "editing process."

    I also notice that if I am interrupted while typing (perhaps by wife wanting help on something) when I return, I can see the wrong words. Thus my failure to see them promptly is partially a "short term memory override" of the image on my retina rather than only dyslexic failure to process it correctly.

    Some of my dyslexia is phonetic in that I type what I am silently saying to myself. Some of the letter substitution is structural similarity related. I know a good bit about how one processes in V1 images like letters (in terms of their more fundamental characteristics, such as line orientations, terminators. etc.)* At this level "b" and "p" are identical (one terminator, one vertical line, one closed curve). Their phonemic structures also differ only by fact one is "voiced" and the other is not. Both are "plosive" (closed lips quickly open), and they share several other phonemic aspects. They are difficult for me to avoid making mistakes on when typing and hard to see their substitution mistakes when reading. (Reading is a highly automated process.)

    SUMMARY: Yes, I think they are related, but many factors are involved. There is no single defect, although serious prosopagnosia can be induced by small strokes. It is not limit to faces. There is a well documented case of a farmer who prior to his stroke recognized every cow in his large herd, remembered who it mother was and if still owned could point her out. After the "micro-stroke," he could not tell one of his cows from another, but only prosopagnosia was the main sequela of his stroke. It is known that one small area in the brain is associated with face recognition, but I think it is used for most recognition of familiar individuals, be they people, cows, or dogs etc.

    I will close with a joke:

    What does the dyslexic, agnostic, insomniac do?
    Answer:
    He lays awake at night and wonders if there is a Dog.

    ---------------
    *This is also very compatible with, if not strong support for, my "crackpot" concept of how all perception works. (My "we perceive an internally constructed real-time simulation" not the "emergent transform" of retinal images as is the accepted POV in cognitive science.) Anyone wanting to know more about how I think perception works see:
    http://www.sciforums.com/showpost.php?p=1294496&postcount=52
    But be warned, it is about eight printed pages. It includes several proofs that the standard POV of cognitive science is simply wrong, and explains many things easily that have no explanation within the framework of standard cognitive science. If you are interested in perception please take the time and effort to read it - skip the first part that is just reply to someone else.
     
    Last edited by a moderator: May 26, 2008
  13. Enmos Valued Senior Member

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    Thank you for this post Billy

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    Good joke btw, took a few seconds before I saw the Dog thing

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    I recognize this. It's got nothing to do with dyslexia.
    I think it's caused by being 'in the moment', you already have in your mind what you want to say and are too preoccupied by your putting your thoughts into words to realize your made a spelling error.
    I sometimes forget to conjugate verbs etc. and just write down the base verb. It gets annoying sometimes lol
     
  14. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I tend to agree, but think it is strongly related to my theory of how perception works, so in that sense it does have to do with dyslexica. It is really what is in real time simulation of the world at the time I am typing, but not later when I return.

    Again, in my POV we DO NOT see the image on our retina. That is why illusions exist, visual dreams with eyes closed are real experiences, etc. I.e. I am actually perceiving what I simulate to be the external reality, not the image on my retina.

    This is how you mistakenly recognize an approaching stranger as a friend also, until the error between the external reality and your internal simulation of it be comes large enough to force a sudden revision of the simulation that you are perceiving.
     
  15. Enmos Valued Senior Member

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    I agree with this.
    But the example I gave about verbs in my previous post was about myself, and I am not dyslexic at all.
     
  16. ranoutofclevernames Registered Member

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    Prosopagnosia is associated with damage to Fusiform Face Area (FFA), located in right hemisphere's fusiform gyrus. The structurally analogous area in the left hemisphere is, ta da!, the Visual Word Form Area (VWFA).

    However, damage to VWFA usually results in a deficit far more severe than dyslexia per se. It is called Pure Word Alexia, sufferers of which read letter-by-letter. To be fair, reductions in VWFA or minor damage to the area may resemble dyslexia as we know it (a very heterogeneous condition/umbrella term).

    I like the comment on "chunking." I consider myself dyslexic, though I have been tested and not officially diagnosed. Sometimes I see text and feel like I am swimming in symbols.

    I am pretty good at recognizing faces. However, as I alluded to, since reading is a complex process, a disability in reading can arise from many different locations or steps in the process.

    Another hypothesis for dyslexia implicates the arcuate fasciculus. This fiber tract connects Broca's Area (speech production/motor speech representations) with Wernicke's Area (speech comprehension/sound representation). Anecdotally, I can relate to this hypothesis because I can see a totally common word ("continue") but still feel the need to subvocalize it clearly (in Broca's Area) and relay that signal to Wernicke's Area (which recognizes the sound representation, and maps it onto semantic meaning and associations which are stored nearby in the temporal lobe). Most literature that I have read says that the dyslexic arcuate fasciculus must have reduced white matter, and therefore poor insulation and conductivity of the signal from Broca to Wernicke. In my experience, this manifests when I repeat words subvocally, however, it still does not "register." Furthermore, like I mentioned, the word can be very common ("continue"), and even though I visually recognize it as being very simple and pure in meaning and function, I still need to effortfully subvocalize it and also "hear it" in my head, in order to digest it.
     
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Do not know if still in used but this was called "conduction aphasia" a couple of decades ago. To be part of the three main divisions of aphasia. (Broca & Wernicke's being the other two, which are easier to recognize immediately).

    Is there evidence of direct retrograde conduction (Broca to Wernicke) via the arcuate fasciculus? I had always assumed only Wernicke to Broca path, due to the logic of needing to know what words you want to say your thought in before you start the Broca area process of preparing mussel commands to actually say them. I tend to think of Broca's area as sort of an expanded Pre-motor cortex that evolved with speach. (The actual neural impulse to tongue etc that makes the words is still done in the motor cortex.) Its physical location adjoining the pre motor cortex supports this idea of its origins too.

    I read relatively slowly as I tend to sub vocalize as I do so. I had always considered this to be due to the type of things I read. (Even the non-technical texts tend to be ones that require some thinking as you read. - I rarely read short stories, etc.) You have provided me with an alternative idea. Perhaps I sub vocalize to send what I am reading back to Wernicke's area? That why I want to know if the arcuate fasciculus is a two-way street. If you are not deaf, there is always a way back via the ears and it at times causes stuttering, but not when singing (rhythm and music in general has its own processing area quite distinct from Wernicke.)

    BTW, a strong welcome to Sciforums - You know some things in an area still of interest to me (after my interest in physics sort of died). I have a "crackpot" concept of how perception is achieved. An alternative to the accepted POV that it "emerges" after many stages of neural processing of sensory input signals. Fact that visual input is immediately separated into "characteristics" in V1 (and some in V2 also) which go to quite separated regions of the brain for further processing and NEVER COME BACK TOGETHER in the same neural tissue is a great problem for the conventional POV about perception, but not for my theory.

    Also my theory requires the massive retrograde fibers from the parietal to both the LGN and to visual cortex. Few know it (perhaps because it is an embarrassment for the conventional "emergent" POV of perception) but there are slightly more parietal to visual cortex retrograde fibers than those coming from the eyes via the LGN! (Link below gives reference to this little known fact.)

    I hope you will find time to read and comment on my POV about perception.

    See:

    http://www.sciforums.com/showpost.php?p=1294496&postcount=52
    for details, and evidence supporting this non-standard POV. It is a long read, about 8 pages if printed, and more about how free will may be possible without violation of laws of physics than the RTS, but some of the evidence for the RTS is provided
     
    Last edited by a moderator: May 2, 2009
  18. visceral_instinct Monkey see, monkey denigrate Valued Senior Member

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    I have a mild version of prosopagnosia, but definitely not dyslexia.

    I have a hard time recognizing faces unless they're very distinctive.
     
  19. ranoutofclevernames Registered Member

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    link doesnt work?
     
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Thanks. I have edited post to be:

    See:

    http://www.sciforums.com/showpost.php?p=1294496&postcount=52
    for details, and evidence supporting this non-standard POV. It is a long read, about 8 pages if printed, and more about how free will may be possible without violation of laws of physics than the RTS, but some of the evidence for the RTS is provided.
     
  21. ranoutofclevernames Registered Member

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    I dug up an old learning disability test the other day and looked over the results.

    I noticed that I scored in the 1st percentile for an Auditory Attention test where "I was asked to listen to a word while seeing four pictures, and then point to correct picture for the word. This task increases in difficulty in two ways: the sound discriminations become increasingly difficult and added background noise increases in intensity. "

    I have always thought I was dyslexic, but I've never been diagnosed with it. I did get accommodations for learning and reading difficulty, but there was never really a succint diagnosis, and I have a feeling they tend to grant accommodations to most people who shell out the money for getting tested.

    Still, what is surprising is that I did fine on Phonemic Awareness (89th percentil): 68th percentile on Sound Blending (integrating phonemes/syllables into their whole words), and 99th percentile on Incomplete Words (identifying words that have one or more phonemes missing; auditory "closure" ability).

    But I guess this makes complete sense. I've always felt I had hearing problems, but I guess I never explicitly realized that it had to do with negotiating inconsistent auditory and visual inputs. This explains why I do fine on standard hearing tests.

    I was surprised to do fine on Phonemic Awareness, because dyslexia is generally understood as a difficulty with phonemes. HOWEVER, this makes complete sense again, because it appears as though the test assesses auditorily receive phonemes and verbally produced answers, whereas dyslexia has to do with the connection of auditorily understood phonemes with VISUAL orthographic correlates.

    Intuitively, I have anecdotal "evidence" in support of this deficit in Auditory Attention. I ALWAYS wear ear plugs, ever since I "discovered" them a few years ago. They really help me focus on reading, and I like to wear them even when walking/on the bus because it just helps me stay "insulated" and keep to my thoughts. I CANNOT read on trains or buses without them, because there are so many people around me. I wouldn't even say that the people and competing sounds/stimuli on the bus = too many distractions, because they don't feel like distractions, since I can't even START getting into reading, much less get started and THEN get distracted, if that makes sense. It would have to be like like the juiciest piece of reading material ever in order for me to get be able to read it in a crowded bus.


    However, I still have trouble reading at a fluid pace, even if I am in my room, door locked, in total quiet. I take adderall now (these test results are from years ago, prior to getting prescribed adderall), which helps. But if my deficit is most salient when auditory and visual stimuli are competing, I don't understand why I am still generally a slow reader across all contexts.

    So I guess it makes sense, since I've been diagnosed with ADHD. And it appears I do have an attention problem that was previously documented, and since that attention problem is specific to the interface or competition between the visual and auditory processes, it makes sense that I would experience a deficit in reading (a process where both are intertwined).

    INterestingly, I've never had too much trouble paying attention in class, but this involves both visual and auditory inputs (teacher's voice, prosodice cues and body language/lip reading). But I guess htat just means that reading and listening aren't analogous, since one inherently involves two modes of external inputs, whereas reading only entails external visual and coded inputs along with internally produced auditory inputs.

    Furthermore, I ahve ordered books on tape in the past, and found them useless. Because I guess it is not strictly the auditory format that I prefer, but rather the ecological validity of absorbing information in class, real-time, transient auditory and visual inputs, with prosodic, emotional, etc. cues to enhance the packaging of that information. Books on tape tend to be just as rote sounding as the look of text.

    And I suppose adderall helping makes a lot of sense, too, since the ability to process information at a higher level, transcending any preference for low-level mode/type of input by which you are receiving that input. So it's a very frontal lobe type of process. (even if that is not the absolute 'root' of the problem, for lack of a better way of putting it).
     
  22. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    To ranout....

    I of course do not know why you read slowly. I do too and think it may be related to my mild, self -diagnosed, dyslexia and also to fact I ususally read material that requires one to think about the text.

    Are your reflexes slow? Reason I ask is that normal reading does require a sequence of fixations and most of the lost time is associated with the supression of all vision during the time the eyes are moving.

    BTW, it is interesting to stand near a mirror and shift you fixation on one eye and then the other. You will be able to see in the mirror that your eyes have shifted, but you wil never see them shift. (Not even a blur - vision is 100% surpressed most of the time when you are reading.)

    As you seems to have some access to research centers, perhaps you can get to be the subject of a RSR test (not sure that is the current name Rapid Sequential Reading) In it you fixatate one spot on the display screen and the words you are to read appear there is rapid sequencial display (RSD). Most people can read about 10 times faster when there are no saccades with vision supressed.

    The RSR (or RSD?) would eliminate the need for reflexes and test only your ability to metally process the stimulus we call displayed words.

    Also you may want to look into what is called "dicotic listening" (spelling may be wrong) - I.e. two different steams of audio played into ear phones you wear, usually with one a male and other a female voice reading different stories.

    If you can not find links about this look up man's name: Broadbent, I think it was. He was an early investigator of what is called the consciousness "bottleneck." Although you are consciously attending to one audio stream, you are fully processing the other, up thru recognition of the words and parsing the steam into sentences. - I will not explain how this was demonstrated, but if you find the literature you will know.
     
  23. Tenshijin Registered Member

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    Im dyslexic. Not to any extreme degree, but it has its complications. I also have OCD.

    Ive always used features and body shape to destinguish who people are. I have a very hard time remembering a persons face if im not very familiar with them. For instance just now a fellow who ive seen every night at work for the past week came in. I didnt recognize him at all until he spoke(has a destinctive flamboyant tone). I can have some trouble with recognition with new shows, or movies with similar looking actors. I remember in highschool i thought two people were the same dude. Both were tall with the same hair and had south african accents. Both were also named sean. One hated me and the other was chummy with me. It took me months to realize, they werent the same person. It took that long before i saw them in the same room together. Then it all made sense.

    I did a prosopagnosia test and scored above average. They were all celebrity faces that i was fairly familiar with though. I live off movies and tv.

    Ive been searching for correlations between dyslexia and face blindness. I feel there must be a relation somewhere. Or the autism. Fck if i know...maybe im being a hypocondriac again...but im pretty sure i have a mild degree of face blindness. I just can remember peoples faces i see day to day and am not close to or converse with more than hi. Older faces are easier. These young faces all look the same.
     

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