Seizures and Epilepsy
WHAT ARE SEIZURES?
Seizures are abnormal electrical activity in the brain.
Brain cells use little electrical pulses sent down "wires" called axons to communicate with one another.
Your brain has literally billions of brain cells, so there is a lot of electricity zapping around in you head!
Abnormal Wiring
Seizure can result from "abnormal wiring" in the brain.
The brain can be thought of as being a very finely tuned electrical circuit.
If the brain gets injured, either through stroke, head trauma, or other injury to the brain, just like any other part to the body, when it heals it forms a scar.
In other parts of the body, aside from leaving a visible mark, a scar may have no negative effect. When dealing with brain cells however, a scar can lead to the crossing of the brain cell "electrical wires".
When dealing with an electrical circuit, crossing wires can lead to a short circuit.
In the right circumstance, this short circuit can lead to a spark of electricity. If the spark spreads to surrounding brain cells it can lead to a seizure.
MRIBrain revealing grey matter heterotopia
Inborn Errors
In some people, as the brain develops there can be abnormalities in its formation. These inborn errors in development can predispose someone to seizures.
Some common developmental abnormalities of the brain are:
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Cortical Dysplasia- failure of migration of brain cells to proper mature location.
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Grey Matter Heterotopia- clumps of gray matter in the wrong location in the brain.
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Polymicrogyria- abnormal organization of the folds on the brain's surface.
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Schizencephaly- cleft in the brain, lined by brain cells
For more information on developmental errors of brain formation please see:
Pang T, Atefy R, Sheen V. Malformations of cortical development. Neurologist. 2008;14(3):181-191.
Diagnosis
The two mainstays of seizure diagnosis are MRI of the brain and EEG
MRI Brain
EEG
ElectroEncephalogram (EEG)
EEG is a diagnostic tool used to measure electrical activity of there brain.
In true epileptic seizures, abnormalities of the brain can lead to electrical sparking activity.
Generate excitement
When rhythmic electrical sparking activity continues for more than 10 seconds, it is considered a seizure.
Diagnostic Tool
EEG can be used to see electrical sparks that can lead to seizure, or the rhythmic electrical activity of a seizure.