Imagine suffering periodic spells of blindness, an intense throbbing in the head and overwhelming nausea on a regular basis.

Shutting out the world to lie in darkness for up to three days might be the only solution.

But for more than one in ten adults in the UK, two-thirds of them women, these symptoms are an everyday reality. Well-known sufferers include Michael Aspel, Maureen Lipman, Roger Black and Steffi Graf.

Migraines not only cause intense head pain, nausea and vomiting but, in extreme cases, loss of consciousness and even paralysis are not uncommon.

Ann Turner, director of the Migraine Action Association, says: "Sufferers will try anything to be free of migraines. It isn't just a headache, there are a whole range of other symptoms which really knock you out."

The initial visual disturbances, from zigzag patterns to lights flashing or blind spots, last from ten minutes to an hour and are followed by throbbing head pain, nausea and vomiting.

Turner describes the feeling as "someone drilling through your eye and out of the back of your head".

Sensory stimulation is painful during a migraine attack to the extent that ordinary daylight becomes too bright to bear and everyday sounds are amplified to deafening proportions.

Dr Anne MacGregor, director of clinical research at the City of London Migraine Clinic, says: "Migraine is much more than just a headache. The whole brain chemistry is much more sensitive to stimuli."

Experts have discovered a change in the size of blood vessels within the brain which causes the throbbing feeling as nerves are stretched around the enlarged blood vessels.

Dr MacGregor explains the over-sensitivity: "Serotonin is released which gives rise to all the other symptoms such as sensitivity to light, sound, nausea. Your brain is not functioning normally and goes through a power cut."

All these changes in the brain are reversed after an attack as the body restores back to functioning normally. Another migraine can't occur until hormones return to normal, a marked difference from tension headaches which can occur one after the other.

It is not solely a condition affecting adults. Children of adult sufferers can inherit an increased likelihood of developing the illness.

Migraines in children differ radically from the adult version. Attacks tend to be shorter, with stomach pains and nausea common symptoms.

Turner explains the impact on children: "The visual disturbances are frightening for them. They may tell you they can see spiders crawling down the wall or can only see half of you."

For adults and children alike, the impact of migraines does not stop at the physical symptoms. The illness has a knock-on effect on everyday life.

Children may need time off school, missing important lessons or exams or even affecting the way they bond with the other pupils.

For adults it is also debilitating. Turner says: "Imagine intense pain for three days. It has a huge effect on your quality of life. You cannot carry on with normal daily life."

Employers are not always understanding of the condition either, according to Turner. "There's no real test for migraine, it is diagnosed by personal medical history. There is a stigma attached to migraines as if it is not a real illness."

Keeping a diary of behaviour patterns prior to attacks will help control the illness. Dr MacGregor's advice is to look for common triggers of the condition, whether it be late nights, stress or missed meals.

Changing levels of oestrogen can be an extra trigger for females before menstruation or after taking contraceptive pills or HRT.

Dr MacGregor believes that balancing triggers against each other can minimise the risk of an attack. After all, prevention is better than cure.

The Migraine Action Association can be contacted on 01536 461 333.