Dr Delvin's column states that dementia is not a feature of ME (The Argus, October 19).

I am not sure whether there is some technical medical definition of the term "dementia" which enables him to make this statement.

However, taking the common, dictionary definition of dementia as "failure or loss of the mental powers", it may be helpful to reassure his correspondent that cognitive problems are a common and well-recognised feature of ME.

They are included in the list of symptoms which is used by clinicians in reaching a diagnosis of the condition.

I was, prior to developing ME, an honours graduate and high-powered Government official. Since developing ME, I have found the drastic reduction of my mental faculties distressing.

The cognitive difficulties include the inability to concentrate, remember things, find the right word, do more than one thing at once (particularly galling for a woman!), understand a sequence, process new information and solve problems - also dyslexia when writing and typing, which for a spelling fanatic is the pits. It's as if I have had 70 points knocked off my IQ.

(Incidentally, I am only in my thirties and my GP, specialist and psychologist all agree I have no symptoms of depression.)

This, like many other perceived problems in life, has actually had its uses, as I have been able to share with my 90-year-old grandmother something of an understanding of how she feels as her own dementia progresses, a common bond which she has found very comforting in an increasingly lonely world.

As your readers may know, ME is a chronic and often very painful illness for which there is currently no recognised treatment or cure. Although improvement is possible, and statistically likely, it can be a life sentence.

During its course, the many and various symptoms fluctuate, new ones appear, old ones abate, vanished ones reappear.

While suffering long-term from ME, it would be illogical to assume that other, treatable conditions may not develop - in my own case, severe Graves' Disease.

It is therefore always sensible to chat to your GP (or ME specialist if you are lucky enough to both have one and be well enough to use them) about any new symptoms which arise, rather than ascribing them automatically to "yet another symptom of the ME".

Depression is common among all classes and age groups. I had it many years ago and beat it - and it is treatable. It can co-exist with ME (hardly surprisingly). However, Dr Delvin is wrong to imply that his correspondent is suffering from depression or some rare form of dementia simply because s/he is experiencing cognitive difficulties.

Sufferers often refer to the cognitive difficulties commonly associated with ME as "brainfog" and, indeed, a leading international support web site for people with ME is named after this cluster of symptoms, www.brainfog.org.

Further exploration for those with this condition or seeking to expand their knowledge of it could include a visit to this cheerful web site and reading the book by Dr Charles Shepherd (himself a sufferer), "Living With ME".

Specific references to research into the cognitive impairment associated with ME can be found on pages 6, 8, 460-462 and 155 - on the latter the symptom of memory deficit is noted as follows: "A significant memory deficit ... This pattern of memory deficit is...different from that seen in people suffering from depression."

-Juliet Griffin, Hassocks