For a person with epilepsy, the fear that they might suddenly lose consciousness, even briefly, can deter them from carrying out basic activities such as swimming, riding a bike, holding a baby or even leaving the house.
This is especially true for the 30 % of sufferers, of the 50 million people worldwide who live with epilepsy, for whom medication is unable to control their seizures.
The means to predict and prevent seizures is now a step closer, after two EU-funded projects developed devices that can monitor and influence brain activity.
Electrical activity is happening in our brain all the time. A seizure occurs due to a sudden burst of intense electrical activity which disrupts the way the brain works. This brain activity can be monitored and recorded by electroencephalography (EEG), using electrodes fixed to the scalp.
‘Like an earthquake’
‘There is some similarity between an epileptic seizure and an earthquake,’ explained Professor Antonio Dourado, a computer scientist at Coimbra University, who led the EPILEPSIAE project. ‘They are unpredictable, but there are signals before the event that we believe can be detected. The problem with epilepsy is that these signals may not be the same for all patients.’
The project developed a prototype alarm device, Brainatics, which is worn by the sufferer to alert them of an impending fit. Electrodes attached discreetly to the head are connected to a device the size of a cigarette packet. This makes a wireless connection to a computer that monitors brain activity and emits an alarm when it calculates that a seizure is about to occur.
“Researchers monitored brain activity in 275 patients for five days, collecting data about the type, time and length of seizures, medication used, age, gender and other details. Project partners used this information to create the European database on epilepsy, which has been made available for the global research community since the project ended in late 2011. It has been commercialised by the Freiburg University Clinic Epilepsy Centre, in Germany.‘Epileptic seizures… are unpredictable, but there are signals before the event that we believe can be detected’.
‘This is the biggest database, as far as we know, about EEG signals. It should help researchers worldwide in their studies of epilepsy,’ said Dourado.
Using the data, the partners developed a computational framework for seizure prediction algorithms, called EPILAB. A real time version of this is installed on the Brainatics device to analyse brain activity and give between five and 40 minutes’ advance warning of a seizure, allowing the sufferer to reach a safe place.
In tests, the prediction software proved successful for a third of patients, offering a potentially significant improvement to their quality of life. The success rate must be increased to develop a clinically reliable device, something Dourado hopes to take forward in future work. ‘Advances in nanotechnology and body sensors would also allow us to do many things that are not currently possible,’ he said.
Stop the fit as it starts
In New York, meanwhile, Dr Antal ‘Tony’ Berényi of Hungary’s Szeged University worked with the renowned Buzsáki Neuroscience Lab to develop a prototype brain ‘defibrillator’, which detects abnormal brain activity that characterises the start of a fit and delivers electrical current to restore it to a normal state, stopping the seizure just as it starts.
The small device implanted beneath the skin on the outside of the skull proved successful in lab tests on rats, reducing the duration of ‘absence’ seizures – epileptic episodes that are most common among adolescents – by around 60 %, from 11-12 seconds to 3-4 seconds.
In an article about the device published in Science in August 2012, the researchers reported that the transcranial electrical stimulation, ‘at the intensities used, neither induced arousal effects when applied during sleep nor affected overt behavior during waking’.
‘The principle is very similar to a cardiac defibrillator,’ said Berényi, who is now back in Hungary working to miniaturise the device and test it on other types of seizure.
The aim is to prevent a seizure entirely after one second, which would mean that, instead of falling unconscious, the patient ‘wouldn’t even lose their gait’, he added.
‘Once you have the device and know it takes care of you, you have some sort of a safety feeling,’ he said.
It could certainly be life changing, and not just for drug-resistant cases of epilepsy. It has none of the long-term implications of brain surgery to remove epileptic tissue, fewer side effects than drugs, and production costs suggest it could be considerably cheaper than lifelong medication.
Over time, it might be used to treat other neurological disorders, and could even allow the brain to self-heal, reducing the incidence of seizures.
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