Palinopsia (No this has nothing to do with Sarah Palin)

No, this has nothing to do with Sarah Palin, unless she has long-lasting afterimages.

When you look at an image, and that image is taken away, you are left with an afterimage. This afterimage usually lasts just a few seconds. There can be a positive afterimage, which means that the colors of the afterimage are the same as in the original image; or there can be a negative afterimage, whereby the colors of the original image are inverted. Those afflicted with palinopsia experiences afterimages more often, and they last longer than they should, even persisting until the following day.

Two patients suffering from migraines took a medication called Topiramate in an effort to alleviate symptoms. Both developed palinopsia. Their palinopsia was either decreased in frequency or disappeared when the patients went on lower dosages of the drug, and when they went off the medication completely, their palinopsia was resolved. What is also interesting is that a third patient on this medication developed Alice-in-Wonderland Syndrome, which was resolved about one month after this patient stopped taking the medication. It is not known through what mechanism Topiramate works to induce palinopsia or AIWS. Topiramate is known to enhance the response of gamma-aminobutyric acid (GABA). GABA is the major inhibitory neurotransmitter, which means it decreases the electrochemical activity of neurons at their synapses. There have been cases of patients taking another medication, Nefazodone, have suffered palinopsia after use. Nefazodone, an antidepressant, works possibly by inhibiting the reuptake of serotonin, another inhibitory neurotransmitter. More research into how these medications work could prove valuable in determining what causes palinopsia and what can be used as treatment.

Palinopsia patients tend to have visual field disturbances that are commonly left-sided. Since the brain’s control of the body is contralateral, meaning the right side of the brain controls the left side of the body, and vice versa, this indicates that the left visual field disturbances indicate right cerebral lesions. Palinopsia occurs in visual fields that are not blind, only dysfunctional. That is to say, the palinopsia sufferer can see and is not blinded due to the disorder, but they suffer visual disturbances.

There have been a number of palinopsia patients that suffer also from generalized seizures. A 20-year-old woman experience visual disturbances after a single episode of a generalized seizure. She stated that she suffered also from dizzy spells and during these attacks, her husband described that she would stare blankly for several seconds. During some of her episodes, she would try to move her eyes, but all she would see was the last image she had looked at. What would happen is that the afterimage would last for several minutes, gradually fading so that the “real world” would fade into her view in increasingly clarity until the afterimage had gone away. The afterimage retained its color and depth the entire time, but the patient was still aware of which was the afterimage and which was the “real world” image.

Another woman, of 73 years, first described her symptoms during a Christmas party. What she saw the entire time was the white beard of a Santa Claus superimposed on everyone’s face. During the next day, she saw some people in the red Santa suit as she went through her day.

Palinsopia may be due to damage in brain areas dedicated to visual association and visual memory. Other palinopsia patients have suffered from parieto-occipital and fronto-parietal hemorrhage. The exact cause of palinopsia, however, remains elusive.

 

My original post can be found here.

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4 thoughts on “Palinopsia (No this has nothing to do with Sarah Palin)

  1. I realky liuke your blog.. very nice colors & theme.

    Did yyou credate this website yourself orr did you hire someone too do
    it for you? Plz repoly as I’m looking to design mmy own blog and would like to find out
    where u got this from. cheers

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