Epilepsy is a common neurological (brain) disorder affecting 1% to 2% of the population. Epilepsy is characterised by recurring, spontaneous, stereotyped seizures. Seizures are the result of bursts of electrical activity within the brain, caused by an imbalance in the chemicals responsible for the transmission of impulses. A person’s behaviour will usually be different during a seizure.
What causes epilepsy?
Everyone has a genetically determined seizure threshold. Anyone can have a seizure if the trauma or disturbance is great enough to exceed the threshold. Factors such as fever, changes in blood chemistry, anxiety, sleep deprivation or alcohol may influence the onset of a seizure. Many people develop epilepsy not knowing why. Where the cause is known, it may be the result of: birth injuries • • severe head trauma • tumours • infections, e.g. meningitis, encephalitis • degenerative or vascular dementias • stroke • hormonal changes • genetically inherited conditions, e.g. tuberous sclerosis
Behaviour during a seizure can vary according to where in the brain the seizure arises. It may present as a convulsion, unusual body movement, a change in awareness, or simply a blank stare. The person may be unconscious or completely aware of what is happening. Seizures are classified as: • partial, affecting a small part of the brain • generalised, affecting the whole brain
The disturbance in the brain begins in or involves a distinct focal area. The function of this area of the brain determines the behaviour during a seizure.
Simple partial seizures
Consciousness is not impaired. May present as: • a tingling, numb sensation or twitching in arm, leg or face • a distortion of light, smell, sound or space • an unexplained fear or anxiety Simple partial seizures may progress to involve the whole brain and often serve as a warning of further seizure activity (aura).
Epilepsy Association of New Zealand © Copyright 2011
Epilepsy, What is it?
Complex partial seizures
• • • • an altered state of consciousness characterised by a change in awareness a blank stare semi