SOME 20,000 Irish people suffer from epilepsy: one in 200 will have seizures at some point. That makes the condition as common as diabetes. If it appears, on the surface, less widespread that is not least because few sufferers advertise it - frankly, very often people are scared of epilepsy, by the thought of sudden, uncontrolled fits.
Records of the condition stretch back to Babylon, but that does not mean it is by now always understood. However as, 4,000 experts from all over the world gather in Ireland for the 22nd International Epilepsy Congress next weekend, the condition is beginning to give up more of its secrets. And last week, alter years of lobbying by the International Bureau for Epilepsy and the International League against Epilepsy, the World Health Organisation launched a global campaign against the condition - a significant development for what one expert described as "the politics of epilepsy".
"Epilepsy" is a catch all description of a tendency to seizures - sometimes described as "an electric storm in the brain" - when the normally well organised brain waves become completely disorganised, either throughout the brain or in a localised area. Triggers for seizures can include allergy, stress, lights and tiredness in 20-30 per cent of epileptics, the condition is associated with learning difficulties.
When epilepsy strikes, particularly when it does so after early childhood, it often seems to have come out of the blue. In fact we are all potential epileptics, each with individual tolerance to those stimuli that cause epileptic episodes. The lower the "threshold" of tolerance, the more susceptible to seizure.
Having a seizure does not always mean collapsing in convulsions - although it can. In simple partial seizures, for example, the seizure is confined to either twitching of one limb, or part of a limb, or to unusual tastes or sensations such as pins and needles in a distinct part of the body.
Seizures may be related to brain injury, at birth or after, or high fevers, brain infections and tumours, and epilepsy can be genetic. But for many sufferers the origin of their epilepsy is unknown.
Some eight in 10 epileptics get their condition under control with medication, but side effects of anti epileptic drugs can include drowsiness or sickness, and affected vision. However, within the past five years, and after a long barren period, the range of medicines clinicians can choose from has increased. There are great hopes for these "designer" drugs - they target specifics areas in the brain, where the older drugs took more of a "blanket" approach calming electrical activity in all areas of the brain - but as far as many experts are concerned the jury is still out. "There have been massive strides in treatment, with many new drugs - took many, too soon after many years," says Dr John Kirker, a neurologoist who is, heading the scientific advisory committee for the Congress. One of the aims of the Congress is to air and collate the latest information from clinicians on these drugs.
Of three papers being presented at the International Epilepsy Congress by a team from Dublin's Crumlin Children's Hospital, two are audits of new generation anti convulsents, which have been used for the last 10 years in Ireland., "These drugs have had a significant impact on difficult epilepsy patients, there's no doubt about it," says paediatric neurologist Prof Joe McMenamin, who leads the team. "We are one of the few countries in Europe where these drugs have been available for quite some time, so the paper is an early long term study.
The other paper the team is introducing is "our first hefty paper" about results achieved with new diagnostic equipment, which has yielded more surprises than, expected.
Using computer recordings of braid waves (EEG) time locked to video, patients are observed at length in the ward and behaviour and EEG minutely compared. One result indicates confirmation of something long suspected that some problems believed to be behavioural are in fact epileptic in origin.
Prof James McMenamin explains: "The parents may say `my child is acting funny' and this would be put down to bold behaviour but, in fact, we might see that behaviour is actually due to abnormal brain electricity. So there might be an indication to treat that patient with medication even though they are not actually having an obvious seizure."
One of the topics set for the International Epilepsy Congress will examine the evidence that brain electricity can cause intellectual disfunction, changes in concentration and changes in behaviour - and there is "a lot of evidence" for this, Prof McMenamin says.
In up to two in 10 patients, medication fails to control seizures. They may then be assessed for surgery to see if their epilepsy can be helped or cleared by removing damaged tissue or by isolating the origin of the epilepsy to stop it overwhelming the brain.
"The next step is to try to identify precisely if the abnormal electricity is coming from a particular area of the brain," says Prof McMenamin. "Then, we can bring the case to Beaumont Hospital, where an assessment team decides if it is suitable for surgery."
Irish neurospecialists are keen to make surgery available to as many sufferers of disabling epilepsy as can benefit. The team at Beaumont hospital is working towards 52 a year, the total projected national demand.
"With the finer, hightechnology images we have now, we are discovering, lesions in more and more people," says neurosurgeon Jack Phillips of Beaumont Hospital in Dublin. These imperfections, or lesions, on the brain can be genetic or damage related. "Very frequently, where people have had epilepsy, of unknown origin, we are finding these discreet abnormalities," Phillips says.
If these are accessible, they can be cut out by laser or burned out. First, the brain is exposed; then electrical charges are applied to its surface and the response recorded so the surgeon can see what part of the, brain does what (this varies from individual to individual). Then, the surgeon will be able to map a nondestructive route to the site of the, surgery.
The team in Beaumont intends soon to extend epilepsy surgery to previously inoperable cases - those where the lesions are in the speech area of the brain. To map the speech area, the patient has to be awake during surgery.
After the brain is exposed, the patient is woken and, through a psychologist, asked questions while the brain is stimulated with an electrical current; when the current prevents the patient from answering, the surgeon knows to steer clear of that spot. The patient is put asleep again for the actual surgery.
Virtually all the brain can now be targeted and many, many areas operated on. The final development, Phillips says, will be image guidance robot system which helps identify deeper areas of the brain through minimal access - "keyhole surgery of the brain".
The best outcome of this surgery, depending on where the epilepsy originates in the brain, is a complete cure, but this is by no means guaranteed.
Another surgical option involves cutting the links between one area of the brain and the next, so that the "electrical storm" can be localised. For epileptics who suffer drop seizures for instance, even a lessening of the severity of the fit can make all the difference, Phillips says.
"Such patients will possibly have visited casualty departments dozens, even 100 times," he says. "They would need constant adult supervision: many wear helmets to protect their heads. They can be given back great quality of life if we can reduce the fits to where they have enough warning to sit down, for [instance, before a fit, or where we can reduce the number and severity of fits."
Mr Phillips hopes that by the year 2,000, 10 per cent of epilepsy sufferers will be suitable for some type of surgery.
At the moment, some 20 per cent of cases of epilepsy cannot be managed, ,,and the search continues for alternative therapies.
One hope lies in a process called Vagus Nerve Stimulation, which is still very experimental. Here, a mild electrical shock is applied to the vagus nerve, which carries information from the rest of the body to the brain. The thinking is that the stimulation could intercept the effect of the chaotic brain activity. The nerve is stimulated from a small electrical generator implanted under the skin.
Dr Gus Baker, of the Liverpool University Department of Neurosciences, who has organised a section of the congress on patients perception of their treatment, has positive findings to offer. "We found that for the majority of people with epilepsy, if their seizures could be well controlled on a single anti epileptic drug then they had a very good quality of life."