Diagnosis of Epilepsy

The diagnosis of epilepsy can be difficult to make and details of the episodes should be obtained in as much detail as possible from both the affected person and any witnesses or onlookers present.

The most important step towards a diagnosis of epilepsy or to confirm that a seizure has occurred is an accurate description of the event from an eyewitness, as well as from the person concerned.

If the description is consistent with a seizure a number of tests may be important in helping to confirm the diagnosis of epilepsy, including the following:

ElectroEncephaloGram (EEG)

This test records electrical activity in the brain. Some types of seizures produce characteristic EEG patterns but a normal recording does not rule out epilepsy. Not all abnormalities detected by an EEG are related to epilepsy. If a characteristic seizure pattern is detected then further investigation may not be necessary.

N.B. It is important to note that some patients with unequivocal epilepsy will have persistently normal or non- epileptic EEG’s.

Brain Scan (usually MRI or CT Scan)

This is useful to identify any structural abnormality of the brain.

A Magnetic Resonance Image (MRI) scan is more sensitive and specific than Computerised Tomography (CT) for detecting small brain lesions and abnormalities, which may be a relevant cause of epilepsy).

Blood tests

These would be necessary to rule out any underlying pathology, and to identify other possible causes of the seizure or event, though any metabolic disturbance is likely to have already been recognized. Blood levels of medications are also monitored.

Video-telemetry

Video-telemetry combines continuous EEG and video recording and is valuable in the specialist assessment of difficult cases of episodes of disturbed consciousness.

It is possible for all of these tests to be negative, and yet for the diagnosis of epilepsy to be established.

Amended November 2008