Science Interviews

Interview

Sun, 8th Jul 2007

Epilepsy

Dr Howard Ring, University of Cambridge

Listen Now    Download as mp3 from the show The Brain, Epilepsy and Out of Body Experiences

Most people are familiar with epilepsy, we may have friends and relatives who suffer from seisures, but the disease it a bit more complicated than that.

Kat - What is epilepsy? What causes it and what sorts of things happen?

BrainHoward - Epilepsy is a disorder of the brain, itís caused when groups of nerve cells essentially fire too fast and the way in which the seisure shows itself is determined by how many nerve cells start firing abnormally. So if only a relatively small number of nerve cells fire abnormally, then the seisure maybe rather limited, for example twitching of the hand or movements of the face. But when the whole cortex, the outer surface of the brain gets involved in this seisure activity, then you have what a lot of people would recognise to be a seisure, what we call a generalised tonic-clonic seisure, where somebody loses consciousness, falls to the ground, they go rigid and they shake. The whole thing can last from a few minutes to longer, occasionally needing emergency treatment.

Kat - What sort of things can actually bring on epilepsy? Are some people born with it, or is it caused by something?

Howard - Yes to all of the above, and others. Certainly it can be associated with various genetic syndromes that people are born with, it can be caused by brain damage, thereís a part of the brain called the temporal lobe which is particularly vulnerable to not having enough oxygen during the birth process. So people whose birth is unduly complicated can sometimes have seisures. And sometimes a particular kind of epilepsy that some of your listeners may be familiar with occurs in infants and young children below the age of about 5 if they have a very high temperature. These are known as febrile convulsions, and these are convulsions, not epilepsy, and in general people who have febrile convulsions donít go on the have epilepsy. Thatís another important point, you can have seisures with out having epilepsy, and you can have epilepsy with out having very obvious seisures. So itís an increasingly complicated subject.

Kat - And how do we normally treat epilepsy?

Howard - The great majority of people can be very well treated with anti epileptic drugs. Approximately 70% of people who develop full-blown epilepsy, which is repeated seisures; having one seisure really isnít epilepsy, but having a tendency for repeated seisures is epilepsy. About 70% of people will respond well to the first or second anti-epileptic drug they are given.

Kat - How do these drugs actually work? It sounds incredibly complicated to give someone a drug that actually effects their brain in this way.

Howard - It is actually incredibly complicated, sufficiently complicated that I canít give you a very good answer, Iím not sure than many people can. But basically, there are different things that can excite or calm down, or inhibit brain nerve cells, and in general things that calm down or inhibit nerve cells, particularly by increasing, in certain parts of the brain, a transmitter between nerve cells called GABA, will help to reduce the number of seisures. Thereís another neurotransmitter called glutamate, which excited nerve cells and too much glutamate activity causes fits. So other groups of medicines that are effective are those that reduce the activity of glutamate. So basically increase GABA or decrease glutamate and that will have an effect.

Kat - So when we see people having Ďfitsí theyíre quite dramatic, but what are the other things that epilepsy can bring on, the other problems. Obviously, for peopleís families it can be quite distressing.

Howard - Absolutely. Well thatís a very good question and what we always say is that epilepsy is more than just fits, or seisures. Seisures are a symptom of epilepsy. One of the important ones, and I am very eager to mention this, is that there is a social aspect to the condition. In the past, people were frightened of other people who had epilepsy. People were afraid that seisures meant that you were possessed, or that there was something awful happening. And Iím very pleased to have this opportunity to say thatís not the case at all; seisures are simply a symptom of a localised disease in the brain that can be adequately treated. Really, what happens is that we need to educate people that seisures are nothing awful and top try to help people fight the stigma that sometimes applies to epilepsy. So thatís one kind of treatment, education for social stigma.

Another thing that Iím particularly interested in the relationship between epilepsy and psychiatric symptoms, although the two might seem to be rather different. First of all they both involve the same organ, that is the brain. Sometimes what happens is if you have a discharge in one part of the brain that can actually generate a range of psychiatric symptoms. These might be to do with depression, you might sometimes, rarely, but sometimes quite dramatically, get symptoms of what we call psychosis. Seeing things that arenít there, hearing voicesÖ

Chris - Havenít people felt profoundly religious experiences as a result of epilepsy?

Howard - Well this is where it gets extremely interesting. The brain, as you know, does all sorts of interesting things, pretty much it does everything we are and everything we do. Epilepsy is a manifestation of increased activity in those brain cells and therefore all the things that we can do, essentially, can be generated by seisures. But because itís an abnormal way of activating these nerve cells we get things broken up, we donít get the whole pattern of behaviour. So people have had intense religious experiences, there are accounts of a feeling of conviction, an absolutely free-floating certainty. ďThis is right!Ē Which just exists by itself, which is rather unusual.

Chris - I suppose if we can home in on which bits of the brain are giving these experiences then, paradoxically, that can give us clues as to what those bits of the brain do, and therefore a better understanding of how the brain works.

Howard - Thatís absolutely right and in principle it should be very straightforward; you map where the epileptic focus is, that is the site of the seisure, with the behaviour and you know exactly whatís going on. Itís not as simple as that for several reasons. First of all, because it turns out that there are several different parts of the brain that can generate individual emotional psychiatric symptoms. Secondly itís very hard sometimes, particularly if you donít have deep electrodes, wires in the brain recording exactly where the seisure is starting, to be sure exactly where the seisure is starting. Nerve cells are of course, a microscopic thing, and weíre looking at chunks of brain millimetres or bigger.

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