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Visual discrepancies/ sensory gating?

Discussion in 'Neurological/Neuro-sensory' started by justy, Nov 30, 2011.

  1. justy

    justy Senior Member

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    Hi, ive noticed a lot of talk on different threads recently about brain problems leading to sensory gating deficit (inability to filter out unecesessary external stimuli) and visual problems and i notice that its not often talked about in its own right. The thread on the Herv -w reactivated endogenous retrovirus got me hooked on thinking about this issue.

    I have a number of visual issues, most notably blurred vision not corrected by glasses as well as severe eye pain, eye droop etc. Dr Myhill explains this as being attributed to mito dysfunction - the eyes have a high need for ATP and will be one of the first parts of the body to go if we push (along with the brain which cant recycle energy the way the rest of the body does.

    The other issue is what i want to discuss here and i am very interested to see if anyone else feels this way. I have a general feeling of unreality which is more pronounced when i am outside - even if it is not noisy, but the main issue is that when i walk the movement of the things around me as my eyes and body go up and down is very hard to tolerate. I know that sounds nuts so i asked some friends if they noticed the up and down movement of the trees, buildings, floor etc when they walked and they all said no. I have tried very hard to not notice it, and mainly my brain seems to filter it out well enough for me to cope, but other times it is so marked i feel it makes me very disorientated and woozy.

    Any one else? Is this what they mean by sensory gating deficit?

    All the best, Justy.
  2. L'engle

    L'engle moderate ME

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    I don't know if this is what is meant by sensory gating deficiency. I've noticed though, the hyper-realness of reality, particularly outside. The way the different layers of a background move along in relation to each other seems very pronounced. I can't remember if it was like this when I was more well.

    Interesting topic!
  3. phaedra17

    phaedra17

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    Do you think this is why some of us have 'night blindness' or 'tunnel vision' issues?
  4. hurtingallthetimet

    hurtingallthetimet Senior Member

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    i also have very blurry vision and night blindness, movement noise light crowds traffic all make me dizzy and overwhelmed and cause me to panic...
    i was never like this before i was ill...so many other issues and problems have come with fibro/cfs it seems..

    the eye doctor tells me i shouldnt have the blurry vision with new eye glasses prescription but i do...one eye doctor that was very rude when i told him that i couldnt see at night...told me that no one can and he said it in a way as to belittle me it seemed
    ..which isnt true..my hubbys eyes are like an owls at night...
  5. Marco

    Marco Old blackguard

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    Guilty as charged Justy.

    I've been looking at this quite a bit lately and hope to put something coherent together soon which suggest a sensory gating deficit as playing a key role in our symptoms (not necessarily as the cause of the disease but as a resulting neurological mechanism).

    Basically, sensory gating refers to a fundamental physiological process that allows us to focus on salient sensory information while filtering out extraneous 'noise'. In other words its fundamental to survival to be able to attend to stimuli that suggest danger and not to everyday ongoing sensations. The startle reflex is an example whereby a sharp loud noise makes us jump but if the noise is repeated and not associated with any obvious danger then over time we become habituated to it and it becomes just more background noise. Sensory gating can be tested using a paired response paradigm. What should happen is that the original stimulus (eg an auditory click) produces a strong response but subsequent clicks less so. If there is a sensory gating deficit then the ratio between the initial and subsequent responses is altered with the initial response lower and subsequent responses not fully attenuated. Rather habituating ongoing and non harmful stimuli these signals continue to flood in and are understood to contribute to various forms of sensory overload in conditions such as autism; schizophrenia; bipolar disorder.

    I've come across a sensory gating deficit being demonstrated in the above conditions plus Alzheimers; IBS; Interstitial Cystitis/Bladder frequency; PTSD and Fibromyalgia. Its hasn't been properly studied in ME/CFS.

    I have the same feeling of unrealtity as you do when outside and find being in supermarkets very difficult for reasons I can't put my finger on whether its crowds, noises; smells; lights or all of the above. Also driving now exhausts me. It seems as if everything is happening too quickly but I also have VERY acute situational awareness in that I'm always very alert to road conditions or cars approaching a junction etc.

    A gating deficit can of course affect any sensory modality but sticking with vision I don't know if you saw this thread on another forum which is to look at vision problems in ME/CFS?

    http://www.mecfsforums.com/index.php/topic,10604.0.html

    which includes :

    Here's a few further links that you might find interesting.

    A blog that discusses some of these issues :

    http://blog.progressivehealth.com/omega-3_deficiency_impedes_nervous_system_function.html

    .. and a paper discussing the development of a questionnaire for assessing sensory gating deficits in schizophrenia. Its a dense paper but you might find the content of the validated questionnaire interesting

    http://schizophreniabulletin.oxfordjournals.org/content/early/2010/06/04/schbul.sbq054.full.pdf

    I could ramble all day, but one final thing that I came across which I found astounding. I'm sure you have heard of 'chemo fog and chemo fatigue'? Apparently up to 40% of women receiving chemotherapy for breast cancer develop post traumatic stress disorder (which as above involves a sensory gating deficit). In a mouse model it can be shown that chemo drugs can cause a sensory gating deficit which appears to be due to oxidative stress.

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715916/

    It also appears that a sensory gating deficit can be treated with the glutathione precursor and antioxidant N-acetylcysteine :

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855017/
  6. Enid

    Enid Senior Member

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    Very interesting Marco - all spoken of is very familiar but much eased now. Driving I would not attempt as events move too rapidly (and fast talkers - but I do recall everything said later on). There seems to be a general delay in processing and too much sensory input overwhelmed and only confused. I've tried the supplements mentioned at various times - perhaps they did help. Part of the visual disturbance definately involved muscles - it took time to readjust from the distant to the nearby - depth vision was very impaired too.
    rosie26 likes this.
  7. justy

    justy Senior Member

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    Thanks Marco for the links - ill have a peruse when i have time. It all looks very interesting, especially the idea that it could be caused by oxidative stress. I know from Mito tests etc with Dr Myhill that i have a very high level of oxidative stress and terrible antioxidant functioning (even with supps) I guess that lifting the methylation cycle block could help with this.

    Fo me also as with others above i have terrible night vision - even when i was in a supposed remmission these problems remained. Supermarkets are definately the pits and will always cause a bit of a panic if im not at my best. I also understand the whole driving thing - i only drive a short distance if i have someone with me otherwise i feel very vulnerable. I feel like you Marco -hyper aware but fuzzy all at the same time.

    Im sure these kinds of problems are one of the reasons PWME have panic attacks as the hyper reality feelings and movements can make one feel very strange indeed.

    One thought i had from the links (havent read it yet) is that if chemo drugs cause then then perhaps Rituximab ( at least for some of us) would not be a good idea if it increased ox stress?

    Also wondering if this could mean we have a similar thing going on with reactivated endogenous retroviruses as those with MS and schizophrenia could have?
    Justy.

    P.S sorry that others have this too, but nice to know im not compeletely crazy!
  8. justy

    justy Senior Member

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    Just re read your post Marco - the bit about startle reflex is also of interest - i have always (even before M.E) had an exaggerated startle reflex, as i hear an unexpected noise my body jumps apparently simultaneously. It doesnt seem to matter how many time i hear the noise or what it is. When i was very severely ill my husband breathing in bed would cause my startle reflex to ping off with every out breath -simply horrible.
  9. Marco

    Marco Old blackguard

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    Hi Enid

    Being overwhelmed by sensory input manifests itself, for me, most frequently in the constant 'tired but wired' feeling and also I think contributes to our insomnia. At bedtime I find myself lying there seemingly re-running all the (non) events of the day as if my brain hasn't fully processed them as they were happening. Anything out of the ordinary, even something pleasurable, like a rare afternoon trip to the cinema, leaves me totally overstimulated, unable to sleep and wiped out the next day.

    Then of course there is PEM/PENE which could easily be conceived as analogous to sensory overload episodes in autism; periodic hallucinations in schizophrenia or the manic phase in bipolar disorder.

    Of course PEM can also be explained as an extreme adverse response to exercise (whether due to depleted mitochondria; oxidative stress or a 'cytokine storm' - which I do believe underlies ME/CFS). The extreme response to exercise though doesn't explain our ongoing symptoms, particularly some of the odd ones such as food/chemical/drug sensitivity or sensitivity to light; sound; temperature etc. A gating deficit where we are unable to filter out ongoing noxious sensory data can explain ongoing symptoms when we are not physically or mentally stressed.
    rosie26 likes this.
  10. justy

    justy Senior Member

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    Hd to look this up after reading about it in one of Marcos links - i dont really uinderstand it, but theres a lightbulb going on somewhere in my brain.

    http://en.wikipedia.org/wiki/Prepulse_inhibition

    Yet more links with schizophrenia and alzheimers ADHD and others. This could explain my problem with startle reflex.
  11. Marco

    Marco Old blackguard

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    Hi Justy

    I seemed to have missed your earlier post.

    I think we probably all vary in how strong the startle reflex is (ever been accused of having 'bad nerves'?) but the problem comes when you react in a similar way to subsequent noises (or any other stimulus).

    Interestingly the strength of sensory gating varies in the 'normal' population as well as being strongly associated with various conditions/diseases so its not a normal/pathological thing.

    Pre-pulse inhibition is another term for the strength of sensory gating if you're googling around this stuff. Basically the the pre pulse signal when gating is functioning correctly should attenuate the startle reflex.

    There are a few interesting points in the Wiki article :

    PPI is weak (i.e. there is a sensory gating deficit) in unaffected direct relatives of schizophrenics suggesting a genetic predisposition to developing schizophrenia;

    PPI is stronger in males than females (which would suggest that females are more susceptible to a sensory gating deficit).
  12. justy

    justy Senior Member

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    Yes Marco that is my point exactly, that subsequent noises cause the same response in me as the first noise. I haver frequently been accused of having "bad nerves" and in fact was misdiagnosed as having anxiety disorder for many years by GPs. Funny though that even when im not suffering from anxiety regularly i am still ill. Actually for me understanding how these mechanisms could be working E.g the posibility of it being a sensory gating deficiency make the anxiety considerably less, especially when i attmept to be out in the world.

    I imagine that, altthough it is not specifically mentioned people with Autism may have similr problems with stimuli. My brother is Autistic and i grew up around a lot of PWA, reading Donna Williams' book "nobody Nowhere" is a real eye -opener into how these sort of sensory/visual problems feel.

    All the best, Justy.
  13. Enid

    Enid Senior Member

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    Marco - your post 9 - it is a very complex condition - not understood yet but producing (whatever the description) similar neurological problems. I think more understanding of the brain stem control functions would help - for that appears to be "infected"/dysfunctional.
  14. u&iraok

    u&iraok Senior Member

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    I have this sensation, too, and the inability to tolerate multiple stimuli. I am super-sensitive to noise in general but more than one noise at once makes me absolutely crazy. Crowds, supermarkets, etc. are difficult. Even peoples' voices can be difficult and I hate having this problem. Motorcycles and kids in those stupid little cars that have something added to their exhaust to make them loud makes me want to shoot out their tires. Barking dogs...okay I'll stop my rant. I have to keep the t.v. on low and only watch calm things like old movies.

    I also have blurry vision and impaired night vision.
  15. Scarlett

    Scarlett

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    I have a similar strange sense of detachedness and unreality, particularly in supermarkets or parties, where there is a lot of sensory stuff to take in. I find myself having conversations with people, but feeling as though I'm separate from the scene, watching myself talking, like there's a curtain between me and the world I'm trying to communicate with, very strange.

    Of course, part of the causes of 'unreality' must be pain or discomfort which makes it hard to concentrate, for instance this week I had to stand in a queue at the post office, and I was so uncomfortable by the time I got to the counter that I was trying very hard to appear 'normal' because I was shaking and my knees were giving way.

    There's one particular shop in our town that I can't stand at all - I think it's something to do with the light in there, flickering flourescent tubes, and the ceiling's quite low. I can't put my finger on what's wrong with it, but I always feel really queasy in there.

    I've just started to develop the strange sensation you described of the world 'moving' this week, for the first time. It's really unsettling, just moving my head leaves my eyes behind, and everything goes a bit 'bleary' for a second - very subtle but enough to make me feel more 'unreal', it's like that feeling you get in a lift when it stops and your insides keep going. It's so weird this condition! Never fails to surprise me, and I've been ill for 5 years! Really interesting subject, thanks for posting it
  16. hurtingallthetimet

    hurtingallthetimet Senior Member

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    ive asked a few doctors about the blurry vision...not corrected with glasses and been told that i should see fine and then moved along...i cant see fine my eyes are very blurry...i cant see at night at all...was told no one can see to drive at night...thats not true my hubby has great vision at night...im very frustrated by all of it..but nothing i can do..ive seen several eye doctors and its always the same..the lens are correct so i should be able to see..

    i get very overwhelmed and overloaded by lights sounds movement etc...would love to be able to see as good as i am told my glasses are
  17. xchocoholic

    xchocoholic Senior Member

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    Been there done that. Mine went away about the same time as my ataxia vanished. This appears to be common in gluten intolerance. Theglutenfile describes this ..

    I had visual problems from too many carbs too tho. Blood glucose issues affect our eyes.

    Tc .. X

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