What is the basis for the diagnosis of different seizure types?

Updated: May 30, 2019
  • Author: David Y Ko, MD; Chief Editor: Selim R Benbadis, MD  more...
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The diagnosis of the seizure type is based on the repeated, stereotypic occurrence of the same experience in association with focal electroencephalographic (EEG) changes or on recurrent auras leading to a complex focal-onset seizure or a secondary generalized seizure. Resolution of the recurrent clinical phenomena with anticonvulsants is presumptive but not diagnostic evidence for epileptic seizures.

The clinical diagnosis is difficult, as many stereotypic auras may be induced in areas of the cerebral cortex that are not recorded well on a typical EEG. About 20-40% of auras have an ictal correlate on the scalp EEG. Simple focal seizures may last a few seconds to a few minutes. However, if the aura lasts longer than 30 minutes, it is considered simple focal status epilepticus by definition.

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