Dr Gabriel Uguru
Epilepsy is a neurological disease. It is a seizure disorder characterised by a burst of electrical activity in the brain, which temporarily interferes with the normal working of the brain.
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In normal person, neurotransmitters e.g. dopamine and electrical pulses carry messages from the brain cells and transfer these messages to other neurones in orderly fashion.
But when a seizure occurs, the orderly transfer of messages is interrupted causing many neurones to flood the system by sending messages all at the same time.
This results in a flood of electrical activity, which temporarily disrupts the regular working of the brain so that the person is disorientated, speechless, unconscious or even stop breathing.
There are ca. 65 million people worldwide with the epilepsy disease condition. It is mainly seen in children (including one-third of those with autism spectrum disorder) and those above 60 years old. Its cause is quite broad and sometimes unknown.
In children, some of the common causes are maternal drug abuse during pregnancy, lack of oxygen at birth, electrolyte deficiency in blood e.g. calcium and magnesium, and blood sugar. In the over 60s, strokes, tumours and Alzheimer’s are quite common causes of the disease.
But in general Down’s syndrome, TB, high fever, head injuries, neurone imbalance, scarring of the brain by infections and congenital genetic disorder are frequently seen in epileptic conditions.
The part of the brain that has been implicated in epilepsy cases is the temporal lobes, and embedded into these lobes is the hippocampus, which is responsible for memory and learning.
The hippocampus is quite delicate and susceptible to scarring by seizures, and if untreated, it may shrink and harden, giving rise to hippocampal sclerosis, a common cause of drug-resistant epilepsy in adults.
Epilepsy condition can go away with time in mild cases, but generally epilepsy is currently incurable. However, there are many treatments available to manage the condition and ensure its limited interference in daily lives of sufferers.
Sleep therapy and stress reduction also help in managing epilepsy, and so does avoiding situations that are likely to trigger episodes of epilepsy like watching films with flashing lights. But there are those who may not be susceptible to these treatments especially in cases of hippocampal sclerosis, in which case surgery (i.e. temporal lobectomy) to remove a small part of the brain identified with the epileptic seizure may be a choice.
Also available are neurostimulator implants. They are increasingly becoming the trend and work by transmission of electrical pulses through the brain so that electrical activity is recorded, allowing for control of seizures.
The most common of these neurostimulators is the vagus nerve stimulation (VNS) therapy. The VNS device capitalises on the role of the vagus nerve found in the neck, which carries messages between the brain and other areas of the body.
A generator (similar to a pacemaker) is placed under the skin near the heart. This generator is programmed to send electrical impulses at regular intervals to the vagus nerve through a thin wire. These impulses are then transmitted to the brain so that the number of seizures are reduced by controlled stimulation of the brain.
An increase in heart rate is also an indication of an imminent seizure or a seizure actually happening. This can be averted or the severity lessened by the VNS device, which upon detecting an increase in heart rate sends more electrical impulses to the vagus nerve to stimulate the brain accordingly.
In other neurostimulators, part of the brain called the thalamus is specifically targeted for stimulation. The thalamus is found near the centre of the brain and connects nerve fibres to other areas of the brain.
First, a neurostimulator is implanted either under the scalp just within the skull or in the chest followed by implantation of electrodes in the brain. Electrical impulses are released by the neurostimulator through thin wires connected to the electrodes so that electricity is transferred directly to the brain.
Neurones that are in the path of an electrical pulse can be turned off reducing the excitability of the brain and thus the less likelihood of seizures. Current neurostimulator devices also record brain signals which can be used to programme the devices according to individual needs.
Mathematicians are now homing in on data collected from epileptic patients’ brain signals or Electroencephalography (EEG) recordings to develop mathematical models tailored to each individual.
With this modelling, which uses algorithms to study the pattern of each patient’s brain activity, scientists can predict who is at risk of developing a seizure or when a seizure will happen so that the patient can be notified.
Scientists at the University of Southern California, USA, have even reported being able to narrow a seizure occurring within a 5- to 60-minute window using mathematical modelling. Such a warning system is extremely invaluable as it would allow patients to have seizure episodes in a safe and regulated environment.
Patients receiving such a warning could stop or reduce activities such as watching TV or playing video games with flashing lights, which may be a trigger to a seizure episode.
If for example the person is working with a heavy machinery or driving, receiving a warning that a seizure episode is imminent would cause the person to stop and seek a safe place, ready for the seizure.
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