Children with epilepsy sleep badly and as a result often are sleepy during the day. Unremarkably perhaps, they also tend to do badly at school. The two undoubtedly are related, however the link may be more complex than previously thought.
According to the UK Charity ‘Young Epilepsy’ more than one in five people with epilepsy have learning or intellectual difficulties. Poor academic results are common in children with epilepsy. Evidence suggests that up to half of all children with epilepsy underachieve at school.
Two years ago, Dr Charline Urbain from the Free University of Brussels, Belgium, published a small but important study of four children with epilepsy.
Dr Urbain is part of a team working in the University’s Neuropsychology and Functional Neuroimaging Research Unit. Headed by Professor Philippe Peigneux, this unit is a world renowned centre of excellence for studies into the diagnosis and treatment of sleep disorders.
In her study, the ability of the four children with epilepsy to recall learned pairs of words after a night’s sleep, was compared with that of children without epilepsy. Recall performance was significantly worse in the children with epilepsy – a phenomenon the researchers believe to be related to ‘sleep-related declarative memory consolidation’. Basically you need a good night’s sleep to lay down strong memories.
Interestingly, one of the children with epilepsy showed a normal sleep pattern and better memory recall when treated with hydrocortisone.
Encouraged by these and similar results, the Charity ‘Young Epilepsy’ is now funding research to find out more about the educational problems of children with epilepsy and the role of sleep in learning. The Charity has funded a research project by Professor Helen Cross, UCL-Institute of Child Health, Great Ormond Street Hospital for Children NHS Trust, London.
Speaking in Brussels at a press conference held during last week’s meeting of the European Paediatric Neurology Society Congress, Professor Cross said that even children with the mildest forms of epilepsy show some measurable learning loss. She believes this may be related to spikes of brain electrical activity called epileptiform discharges. These are similar to the electrical disruption occurring during a full epileptic seizure, but do not reach the threshold to trigger a seizure. These abnormal electrical discharges are common during sleep amongst people with epilepsy and have also been observed in children with ADHD.
“There is research to show that people lay down their memories during sleep, so if you test someone for word association, or paired words and then test them again the following day after a period of good sleep, they perform better. We also know that if you interrupt sleep, the results are not so good. We also know that certain types of epilepsy, in which there is continuous epileptiform activity during sleep, can have a major impact on memory – and by treatment, that can improve again,” said Professor Cross.
Her Unit’s research project is looking at a series of children with different types of epilepsy, including children with focal epilepsy requiring surgical treatment and children with benign epilepsy who have epileptiform discharges during sleep.
“We are looking at children controlled by medication and at those who have continuous epileptiform discharges and hopefully looking at treatment – testing them before and after periods of sleep, and before and after periods of wake, to see whether there is an impact of the epileptiform discharges and indeed whether this interferes with sleep pattern by sleep staging.”
Epilepsy can have a devastating impact on children and their families and seizure control is very important, said Professor Cross. However if the new research does confirm the link between epileptiform discharges, poor sleep and poor learning, the implications may include more aggressive treatment of childhood epilepsy, aimed not just at stopping seizures, but at damping abnormal nocturnal patterns of brain activity.
“This could have implications for us treating discharges in a more aggressive way than we have been. Traditionally we have thought that unless there is a seizure, we should not be treating – unless there are virtually continuous epileptiform discharges during sleep. If we confirm that epilepsy interferes with memory and with consolidation of memory, this is going to have implications for how we treat children. Hopefully we should start to have some results next Summer,” said Professor Cross.
Ian Mason