08 July 2007

Interview with 

Dr Howard Ring, University of Cambridge


Researchers use functional magnetic resonance imaging (fMRI) to reveal brain activity during emotional situations. Image credit: Inge Volman et al.


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, it's 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, there's 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 don't go on the have epilepsy. That's another important point, you can have seisures with out having epilepsy, and you can have epilepsy with out having very obvious seisures. So it's 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 isn't 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 can't give you a very good answer, I'm 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. There's 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 'fits' they're quite dramatic, but what are the other things that epilepsy can bring on, the other problems. Obviously, for people's families it can be quite distressing.

Howard - Absolutely. Well that's 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 I'm very pleased to have this opportunity to say that's 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 that's one kind of treatment, education for social stigma.

Another thing that I'm 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 aren't there, hearing voices...

Chris - Haven't 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 it's an abnormal way of activating these nerve cells we get things broken up, we don't 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. "This is right!" 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 - That's 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 what's going on. It's 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 it's very hard sometimes, particularly if you don't 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 we're looking at chunks of brain millimetres or bigger.


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