Sterman then tried the experiment on people with epilepsy. EEG electrodes were attached to the subject’s head to record the brain’s electrical waves, or rhythms. These rhythms were first amplified in the EEG machine, and then filtered to select the particular rhythms the subject was trying to modify. Next, these electrical waves were fed into a computer which drove a light display, designed so that if there was any increase in the selected rhythm, the lights moved across the screen. The person could actually see the activity of their brain in visual form, as the light moved across the display. This is called biofeedback (literally, to be made aware of some aspect of body function of which one is normally not conscious).
The subjects were then ‘trained’ by being told to try to make the lights move across the board. They had to find their own method of doing this, by searching for some ‘mind activity’ or act of will which would move the lights in the right direction.
Sterman found that some patients could indeed modify their brain rhythms and that the exercise did help them to control their seizures. In his first trial a number of patients were able to decrease the frequency of their seizures by well over half. Some found that, like the cats, they could do so by sitting still. Others discovered different strategies, and some were highly successful but could not say just how they managed to do it. Like the cats, the patients were rewarded, though not with milk. They were given tokens which could be exchanged for sweets or money every time their brain activity was increased (i.e., the lights moved) beyond a certain point.
Once Sterman had shown that people could learn to reduce their seizure frequency by modifying brain activity, other laboratories were inspired to try similar experiments to see whether there were other anticonvulsant brain rhythms. Many people have fewer seizures when they are alert, and so one of the obvious targets for biofeedback training was to teach people to increase the brain rhythms which occur when you are alert. This was found to be equally successful. People with epilepsy usually have an increase of slow rhythms in their brains, and so people were taught to use biofeedback to reduce this slow activity. It was found that this exercise too helped to reduce seizures.
OTHER BIOFEEDBACK METHODS
Other biofeedback methods make use of a slightly different principle. One of the first investigators was Schwab in the 1950s who argued that if people could be stimulated at the onset of a seizure, then the seizure could be avoided. He put EEG electrodes on people who had absence seizures. When they had an absence seizure, the EEG recorded spike waves and, as it did so, a light bulb would flash. The flash alerted the person and this shortened the attacks. Eventually the person learned to alert themselves at the beginning of a seizure, without the stimulus of the flashing light. It was hoped that this method would stop the attacks altogether, but this result has never been achieved.
Other workers have shown that biofeedback can be used to teach patients to detect the abnormal electrical discharges – the spikes of epilepsy – which occur between seizures, and to reduce them. Reducing the spikes should also lead to a reduction in seizure frequency. This method too has been quite successful and helped a number of people to achieve a reduction in their seizure frequency.
We tried this method of seizure control at the Maudsley Hospital, and found that we could indeed teach people to reduce their spikes. It then occurred to us that if people could learn to decrease their spikes, maybe they could also learn to increase their spikes. In fact, perhaps the number of spikes that they have was to some extent under their control. We found that this was indeed the case. People were able to increase the number of spikes in their EEG in the same way as they can be taught to decrease them.
This result was interesting in itself, but something even more interesting emerged from the study. We found that many people, once they recognized that their spike numbers were increasing, refused to continue with the experiment. The reason they gave was that they recognized that they had to stop putting a ‘mental brake’ on their seizures. In other words, they acknowledged that they already had special mental ‘tricks’ for keeping their seizures under control, and to stop these tricks would allow their seizures to increase. This was a startling finding, as it suggested that, to some extent, people can modify their own seizures, and can do so by modifying the way they think, and how they behave.
Recently, Professor Niels Birbaumer, from Tubingen in Germany, has used biofeedback in a rather different way. It has been known for some time that the cortex becomes more excitable when it is electrically negatively charged. It therefore seemed possible that if the cortex were made more positive and therefore less excitable, seizures would be less likely to occur. Birbaumer did this using biofeedback.
The experiment he devised was very similar to Barry Sterman’s. Special electrodes were fixed to the scalp and connected to an EEG machine. The output of the EEG machine was interfaced with a computer, which could measure the amount of negativity or positivity. The display on the computer screen showed a space ship, which moved off its launch pad when the subject managed to make his cortex positive. The more positive the cortex, the further the space ship moved; the aim was to try and get it right off its launch pad and across to the other side of the computer screen.
After some training, most people were able to produce this positivity at will, and they were then instructed to practise at home without the help of the machine. Finally, once they had demonstrated that they knew how to achieve increased positivity and could do it easily, they were told to do it whenever they were in a situation in which they knew from experience that a seizure was likely to occur, or, if they had an aura, right at the beginning of a seizure. This kind of biofeedback training is still in its infancy, but certainly some of the people in research trials who have practised it say that it has greatly reduced their seizure frequency.
There is no doubt that biofeedback training in general can help to reduce seizure frequency, and that it might be especially valuable in people who have severe epilepsy which does not respond to medication. So why has this effective, drug-free method of treatment never really caught on? Unfortunately the reasons are very clear. Like so many things, it is a question of time and money. Biofeedback training is very time-consuming. It takes about 10 to 16 hour-long training sessions to learn the technique, as well as regular practice sessions at home. The patient must be highly motivated, and the training team very dedicated. And although the equipment itself is not very expensive, you do have to have a laboratory to put it in and a clinical psychologist to run the programme. Sadly, it seems that biofeedback requires a great deal more energy and commitment than most epilepsy services, or indeed most epilepsy sufferers, are able or willing to give. But if you are happy to work at it, it is a method worth considering.
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You will have many questions about febrile seizures, among them these:
“Will he have more seizures?”
Only 25 to 30 percent of children who have had one febrile seizure will ever have another. If the first febrile seizure occurs in the first year of life, and if there is a family history of febrile seizures or epilepsy, and if the child’s seizure has been long or complicated, then that child may have a high chance (>8o%) of having another febrile seizure. If the child has none of these risk factors, the chances of recurrence may be as low as one in ten.
However, a child who has a second seizure has about four chances in ten of having a third, and after a third, also four in ten chances of having a fourth. But only nine in a hundred children with febrile seizures do have three or more.
“What will happen If he does have another?”
Nothing is likely to happen to your child as a result of the febrile seizure.
• There is no evidence that recurrent febrile seizures damage the brain.
• Children who have febrile seizures do not develop mental retardation as a consequence of the seizures.
• These children do not develop cerebral palsy as a result of these seizures.
• There is no evidence that these children have an increased chance of learning disabilities.
Children who have one, two, or even three or more febrile seizures grow up just like children who have never had such seizures. Virtually the only consequence of a febrile seizure is an increased chance of having another febrile seizure.
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This is often called MRI (magnetic resonance imaging) or nuclear magnetic resonance (NMR). The technique has nothing to do with radiation or X-rays, but records energy given out by atoms as they change their orientation after a brief magnetic pulse. The pictures or images produced have the same general appearance as CT scans, because the information processed by the computer is much the same as. Again it is necessary for the patient to lie still while the images are being taken.
The procedure is noisier than CT scanning and may, in some patients produce a claustrophobic feeling, as the patient is almost entirely enclosed in a tunnel. MRI usually takes about 25-35 minutes, but may take longer. Occasionally some contrast dye is injected into a vein, as in CT scanning, and then the scan repeated to demonstrate some additional details. Children may find the procedure more uncomfortable than having a CT scan and because of this more often need to have a brief general anaesthetic so that they lie still.
MRI gives a much clearer picture of those areas of the brain (the temporal lobes) which are most often responsible for intractable epilepsy, and so patients who are considered possibly to be suitable for surgery will certainly need an MRI. MRI is also useful for children in whom the epilepsy is thought to be due to a congenital malformation of the brain. Because of its greater costs (at present) MRI is unlikely to replace completely CT scanning, but there is no doubt that the level of detail obtained is far superior with MRI.
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