What is epilepsy?
Did you know?
Some people sense that they will experience a seizure. This sensation is called an aura and occurs immediately before the onset of a disorder of consciousness.
Epilepsy is a disorder of nervous system function. It is associated with short-term, recurrent and unpredictable interruptions of normal brain function. Such interruptions are called epileptic seizures.
What is a seizure?
A seizure results from a short-term disruption of electrical activity in the brain. During such moments, the coordinated transmission of messages in the brain is suspended or no longer coordinated.
The number of seizures can vary greatly: from less than one per year to multiple seizures per day. A seizure may happen at any time. It usually lasts a few seconds or minutes, then normal brain activity is restored.
The onset of epilepsy is often reported in infancy but is most prevalent during childhood. The incidence decreases gradually through childhood and adolescence. The reason for this is likely due to the fact that the brain is still developing after birth and is not yet able to cope with the disorders that cause seizures during early stages of development.
The brain controls the majority of the bodily functions – the experience a person has during a seizure depends on the area of the brain that is involved, how extensive the area is and how quickly the disorder spreads. Several different types of seizure are known and each patient experiences epilepsy in their own way.
Some people sense that they will experience a seizure. This sensation is called an aura and occurs immediately (a few seconds to a maximum of a few minutes) before the onset of a disorder of consciousness. The aura usually lasts a few seconds, but may last longer.
Simple focal seizures
These kinds seizures do not cause a person to lose contact with their environment (consciousness is not affected). The brain controls most of the bodily functions. When a disorder occurs in the activity of a particular area of the brain (seizure), it is reflected in the organic system controlled by that particular part of the brain.
Complex focal seizures
People who suffer from this type of seizure lose contact with their surroundings – they lose consciousness. They may be incapacitated and stare but do not respond to external stimuli. Quite commonly, they chew or swallow during a seizure, or perform automatic repetitive movements that seem to be sensible. In some cases they move, but behave strangely and do not respond if spoken to, or respond irrationally. A complex focal seizure may develop into a generalized seizure – most often a tonic-clonic seizure.
These types of seizures always cause a disorder of consciousness. There are several types of generalized seizures:
- Tonic-clonic seizures cause a sudden loss of consciousness. Initially, the body is in tension (tonic phase), followed by rhythmic contraction of the arms and legs (clonic phase). The person may bite their tongue, lose control of the bladder and may suffer harm due to a fall or spasms. When the seizure ends, the person slowly recovers and is likely to fall asleep.
- Absences are very short absence seizures (lasting only a few seconds), but may occur several times a day. The person is still, unresponsive and stares; after the seizure is over, they recover immediately. When such seizures are very short, they are not noticeable by people in the surroundings. The onset of absence usually occurs during childhood or adolescence. Frequent occurrence may cause disturbances in the maintenance of attention, and learning difficulties.
- Myoclonic seizures cause sudden single jerks of the arms or legs. For example, a person may drop an object from their hands, their knees may buckle, their head or torso may tilt forwards and they may injure themselves. The loss of consciousness is very short.
- Atonic seizures cause a sudden loss of muscular tone and consciousness during which a person tilts their head, buckles the knees or falls. Such seizures can cause serious injuries.
Epidemiology of the disease
Epilepsy is fairly evenly distributed in the world. There seem to be no geographical, racial or social barriers. It occurs in both genders, in all periods of life, even in old age, especially during childhood and adolescence, as well as in the elderly population. In more than half of patients, the disease develops before the age of 18. Onset of the disease is also likely to occur after the age of 60. 1 It is estimated that there are around 20,000 patients with epilepsy in Slovenia today. There are about 1,000 new patients every year. Epilepsy may develop at any age.
The content of this article has been created on the basis of the “My Child has Epilepsy” brochure (available in Slovenian under the title “Moj otrok ima epilepsijo”) by members of the Slovenian League against Epilepsy, reviewed by Assist Natalija Krajnc, MD, paediatric specialist, paediatric neurology specialist. Publisher: Medis, d.o.o.
1 Reference: www.drmed.org/wp-content/uploads/2014/06/VI-50.pdf, date: 3 September 2016Download booklet