At each successive visit the reader’s sight was improving. Doctor and patient were pleased by the effect of inactivity, but two years after the first trouble the double and blurred vision returned. This time it was accompanied by a blank spot in the middle of her visual field. She has now been told she is suffering from MS. She wonders about the likely course of her disease.

This is a common story. Trouble with vision is often the first sign of MS and sometimes there may be no other problem for years. Although there are many other causes of double vision, it is always advisable to check out any eyesight troubles. It is easy to understand why someone is reassured if a patient appears to be getting better unaided by any treatment.

One of the first questions that people ask about multiple sclerosis is the nature of its first symptoms. MS used to be known as disseminated sclerosis, because the symptoms were scattered throughout the body, and were transient as it attacked the nerve supply to different systems at different times. This makes it difficult to appreciate the significance of an isolated problem, such as the reader’s double vision, until it is accompanied by other symptoms or a recurrence.

Sudden changes in vision, including double vision and loss of central or peripheral sight, is in my experience perhaps the most common symptom.

Likewise, I was always suspicious when there is a sud- den change in bladder control, whether through urgency, frequency or actual incontinence without obvious cause. Alterations in bowel habit, dizziness, poor co-ordination, loss of balance, are also often the first trouble the patient notices whereas others will have been troubled by a transient loss of muscle power, even very occasionally the actual paralysis of a muscle group.

One group of symptoms that is often not talked about — but in retrospect the family or friends have noted — is a change in the patient’s temperament with periods of forgetfulness or even confusion and inexplicable mood changes. Although the early symptoms — whether muscle weakness, ting-ling of the skin, dizziness, poor co-ordination, changes in vision or change in mood — are now, as always, far more likely to be caused by some other problem than MS, treatment for the disease has improved enormously. Nobody can be certain of the course of the disease. I knew one public figure who had his first attack as an undergraduate at Cambridge, pursued three distinct and distinguished careers and only at the end of his last job, when in his sixties and covered in honour and glory, was it troubling him enough to interfere with his work.

Some cases run a continuous downhill course. Usually the pattern is a relapsing and remitting one for many years. The patient has a bad patch with severe symptoms, makes a recovery to an extent, jogs along nicely for an unpredictable length of time, often years, and then relapses again. Currently the treatment of choice is Interferon beta-1a or 1b. Both reduce the severity of the relapses and their frequency. A new drug Tysabri, (natalizumab), has been introduced recently. It is being used carefully and has not yet been approved by the National Institute for Health and Clinical Excellence, but it has been accepted for rapid assessment. It has been approved by the EU authorities for treatment of the relapsing remitting forms of MS but not for those cases running a steady downhill course.

Tysabri is said to be twice as effective in treating the symptoms and to double the time between relapses, but is also twice as expensive. The quality of life, a difficult attribute to measure, is greatly improved. In three cases only, when mixed with other immunosuppressant drugs, Tysabri caused additional neurological problems.

I suggest reading Multiple Sclerosis: The Questions You Have, the Answers You Need by Rosalind Kalb, and/or Multiple Sclerosis at Your Fingertips, both published by Class Publishing.

• Ask Dr Stuttaford Send your questions to drstuttaford@thetimes.co.uk or to times2, The Times, 1 Pennington Street, London E98 1TT. Please include the following: the symptoms (and how long they have been present), the person’s age, sex and marital status. Dr Stuttaford’s replies cannot apply to individual cases but should be taken in a general context.