Job number: 08VPE0414 Date of preparation: January 2009

What is epilepsy?

Patient counselling tools

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Normal Adult Brain Wave Absence Seizure Tonic-Colonic Seizure

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2 Job number: 08VPE0414 Date of preparation: January 2009

Epilepsy occurs when the normal electrical activity within the brain (i.e. the transmission of nerve impulses) is disturbed for a period of time. This results in temporary abnormal brain function and seizures. Unlike someforms of seizure, which may be caused by illness or brain injury, seizures due to epilepsy have no identifiablecause.1

During a seizure, the electrical activity within the brain becomes faster, with an irregular pattern. This can bemeasured using a number of electrodes placed on the scalp, known as an electroencephalogram, or EEG(Figure 1). Different types of seizure have different wave patterns and the EEG can therefore help to identify the type of epilepsy a person has.1

Figure 1. The EEG

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What is epilepsy?

These different wave patterns and certain symptoms are related to the parts of the brain can be affected by a seizure (Figure 2), such as:1

• Visual disturbances if the occipital lobe is affected

• Inability to speak if the frontal lobe is affected

• Convulsions (jerking and spasms of muscles throughout the body) if large areas of the brain are affected

Figure 2. Parts of the brain that can be affected by seizures

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3 Job number: 08VPE0414 Date of preparation: January 2009

Parietal lobe

Occipital lobe

Cerebellum

Spinal cord

Cerebrum Frontal lobe

Temporal lobe

Brain stem

Other symptoms associated with seizures include numbness or tingling, loss of consciousness, or loss of muscle control.1

The majority of seizures last 1 or 2 minutes. After a seizure, you may feel very tired, confused, weak and havea headache.1

References

1. Merck Manual Home Edition. Seizure disorders. Available at: www.merck.com/mmhe/print/sec06/ch085/ch085a.html.

Accessed on November 28, 2008.