There are a number of possible levels of deficit that can cause problems reading.
It could be due to problems in visual perception, be it problems with the eye itself or the brain's processing of visual signals. If this were the case any problems would effect all vision, not just reading. So problems recognising written words might also be accompanied by problems recognising objects. Having said that in the past people have looked specific visual processing deficits in developmental dyslexia, that by their nature disproportionately effect the spatial frequencies of text. However though this disproportionately might seem to effect reading, it should also effect other things like pattern recognition and be helped by things like different text size. I suspect this is not what
@DokaGirl is experiencing.
Alternatively it could be at the level of processing written language. Here it is interesting to ask is it a focal problem in the reading system or indicative of a general disruption of brain function. Is it just part of brain fog, when you would expect problems with other systems, eg language processing in general, so problems understanding spoken language as well as written language or other unrelated systems such as face recognition or navigation. It is possible to get false focal effects from a generalised deficit such as say reduced channel capacity or limited attention band width.
A good example of this might be that an novice musician when tired could have problems with playing their musical instrument, but not with their proficient driving of a car. So it is not that they have focal musical problems, rather that their limited playing requires more brain capacity than their practised driving, so is more vulnerable to any generalised reduction in brain functioning. That
@DokaGirl raises this issue, suggests she feels her reading problems are more specific than just generalised brain fog. Also for most of us reading is a highly practised skill, so in theory less vulnerable to general brain processing issues. A good comparator might be writing; for most people written language is less practiced than reading, so a generalised brain processing issue might be expected to disprortionately impact on writing rather than reading.
Finally a problem with reading could be specific to the reading system. In general acquired specific focal cognitive deficit would be interpreted by a neurologist or neuropsychologist a problem in the specific brain area mediating that activity.
(Sorry perhaps here on I am getting less clear.)
In relation to myself I find interesting to try to examine whether my cognitive problems are focal or general.
I have problems with reading too. I have not managed to read a book for a number of years though previously I would read two or three a week. I can not rule out that eyesight plays a role, because I have not been able to get to an optician's over the last few years I no longer have glasses of an appropriate prescription, but that is not a sufficient explaination. I am also very aware of difficulties reading text that requires integrating information between lines or even paragraphs, so with academic materials I may have to read a chapter four or five times and still then struggle. This may be a more general information processing load problem or a working memory problem, rather than a specific reading problem. However I do not seem to have an analogous difficulty in understanding spoken language, say a TV documentary. So I am unsure if this is a focal reading issue or a generalised processing deficit.
I further have problems with technical vocabulary including new words. So I can with concentration follow a psychology text as my first degrees were in this field, but I am completely unable to understand an article on the immune system as I fail completely to learn the new vocabulary needed.
In English this does not seem to be mirrored by problems with spoken language, but I do have specific problems with foreign languages. I find it almost impossible to learn new vocabulary, I failed completely in Japan some five or six years ago to learn any every day phrases. In languages I previously spoke, albeit it badly, vocabulary has become jumbled, so when speaking German I will insert French or Gaelic words without realising what I am doing. In French which was always worse than my German I find it virtually impossible now to complete a sentence without inserting words from other languages. It is as if the divisions in my various lexicons have been removed, and I just have a storage area of undifferentiated 'foreign' words.
In navigation I believe I have unambiguously focal deficits. I used to have a good sense of direction, most mammals have a specific area of magnetic material at the base of the scull at the back, which is hypothesised to be a sense organ for direction. Humans have very varying ability to sense geomagnetic directions, however I used to be good at this but have lost it completely. Over and above this I experience episodes of what I describe as 'jamais vu'. In places I know well I have no idea of where I am. I have at these times lost my mental map. I may be able to remember verbally that I turn right at the post box and so give myself some directions. This may only last a few moments or the worst left me resting in the car for two hours, and it is also linked to the current severity of my ME. It can be overcome by always having my SatNav on when I am driving.
My conclusion here is that I have a focal loss of my sense of direction, but further my internal mapping system is also intermittently vulnerable to transient effects, perhaps something like a varying blood supply to the brain.
General processing deficits, presumably generalised effects of our ME on the brain, seem to be intermittent and so hopefully are reversible. However it is not clear if there are focal deficits if these would be reversible.
I have not had a brain scan, so can not say if there is any focal damage in the specific areas involved.
