An electroencephalograph (EEG) of generalised seizure (tonic-clonic type)
Tonic-clonic generalised seizures affect the whole brain and produce abnormal electrical activity at the frontal, temporal and occipital sites. A tonic-clonic seizure is typified by an initial strong contraction of the whole musculature, causing a rigid extensor spasm. This ‘tonic’ phase is followed by a series of synchronous jerks, the ‘clonic’ phase. The patient remains unconscious for a few more minutes (post-convulsive coma), before gradually recovering.
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References
Antiepileptic drugs and centrally acting muscle relaxants. In: Pharmacology, 4th edition. Rang HP, Dale MM and Ritter JM. Edinburgh, UK: Harcourt Publishers Ltd, 2001:566–578.