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23 October 2015

Brain scans identify possible risks for SUDEP

A new study has suggested there could be similarities in structural changes in the brains of infants who die of cot death and adults who die of Sudden Unexpected Death in Epilepsy (SUDEP). And the changes could potentially help to identify those who are at greatest risk of dying from SUDEP.

At least 300 babies in the UK die each year from cot death or Sudden Infant Death syndrome (SIDS). SUDEP claims the lives of 600 people with epilepsy with it being the most common cause of premature death in people with uncontrolled seizures. People with epilepsy are 20 times more likely to die prematurely than those without the condition.

Now researchers at Epilepsy Society have shown that there are significant changes in the volume of grey matter both in the brains of those who died of SUDEP and in those who are thought to be at greatest risk of SUDEP in comparison with low risk cases and healthy controls.

Brain abnormalities

Using high resolution MRI scans to map the different regions of the brain, researchers have shown an increase in the volume of grey matter in regions which play an important role in memory function - the right hippocampal and parahippocampal areas. Studies in babies who have died of SIDS have found similar abnormalities in the same regions of the brain.

Scans of people with epilepsy have also shown a reduction of grey matter in the posterior thalamus, a region which is critical in the regulation of sleep, consciousness and alertness. The extent of the reduction was shown to relate to the severity of the epilepsy.

Both these changes could be important in helping to identify those who are at greatest risk of SUDEP.

It could be speculated that reduced volume of grey matter in the thalamus may lead to an inability to kick start breathing in the case of oxygen deprivation.

Professor Ley Sander, medical director at Epilepsy Society (pictured) explained: 'Our findings suggest that the increase in grey matter on the right side may influence autonomic functions that we do without thinking such as breathing and blood circulation.

‘It could be speculated that reduced volume of grey matter in the thalamus may lead to an inability to kick start breathing in the case of oxygen deprivation.

These changes could be critical in SUDEP. This is the first time that we have used neuro-imaging  to identify potentially useful biomarkers or biological indicators that could be used for identifying those at greatest risk.'

However Professor Sander emphasised that the study was relatively small and that results should be interpreted with caution and would now need to be replicated on a larger scale.

Sleeping position

The study also highlights the fact that, as with SUDEP cases, infants and children who had died of sudden unexplained death and who had structural abnormalities, were found during sleep and lying face down. There was frequently a personal or family history of febrile seizures, creating a potential link between temporal lobe mal-development, susceptibility to seizures and sudden death.

Professor Sander continued: 'The advice to put babies to sleep on their backs is thought to have helped reduce the incidence of SIDS. However with SUDEP we do not know whether people who are found lying on their stomachs have ended in that position as a result of their seizure. Advising that anyone who is at risk of SUDEP should sleep on their back would be premature until we have proper evidence.'

The study looked at 12 cases of SUDEP, 34 people at high risk of SUDEP, 19 at low risk and 15 healthy controls. High risk factors included asleep seizures, frequent convulsive seizures, age at onset of epilepsy and duration of epilepsy. 

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