Spikes and sharp waves - Revision history

EEGpedia at 10:25, 9 June 2017

2017-06-09T10:25:23Z

EEGpedia at 10:23, 9 June 2017

2017-06-09T10:23:59Z

EEGpedia: Created page with "* Sharply contoured transients, clearly distinguishable from and usually interrupt background activities * Almost always negative wave, so pointed upwards on the EEG * Spike:..."

2017-06-09T10:23:17Z

Created page with "* Sharply contoured transients, clearly distinguishable from and usually interrupt background activities * Almost always negative wave, so pointed upwards on the EEG * Spike:..."

New page

* Sharply contoured transients, clearly distinguishable from and usually interrupt background activities
* Almost always negative wave, so pointed upwards on the EEG
* Spike: Duration of <70 milliseconds
* Sharp wave: Duration of 70-200 milliseconds
* No difference in etiology or prognosis between a spike or sharp wave

'''Clinical relevance'''
*If seen in a patient with reasonably high suspicion of a seizure, the predictive value of spikes and sharp waves for epilepsy is high .
*In healthy adults, spikes and sharp waves are seen in about 0.5-1%. In healthy children in about 3-5%. <ref> Okubo et al, Epileptiform EEG discharges in healthy children: prevalence, emotional and behavioral correlates, and genetic influences, Epilepsia. 1994 Jul-Aug;35(4):832-41.</ref>
*After a first seizure, the presence of interictal spikes and sharp waves doubles the likelihood of seizure recurrence. <ref>Berg AT, Shinnar S. risk of seizure recurrence following a first unprovoked seizure: a quantitative review. Neurology. 1991. 41:965-72.</ref>
*The absence of interictal spikes and sharp waves does not prove that the patient does not have epilepsy.

'''Do not confuse with:'''
*[[Small sharp spikes (SSS or BETS)]]
*[[Wicket spikes]]
*[[6 Hz spike-and-wave bursts (WHAM and FOLD)]]
*[[ECG artifact]]
*[[Muscle artifact]]
*[[Eye blink artifact]]

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	*[[Muscle artifact]]		*[[Muscle artifact]]
	*[[Eye blink artifact]]		*[[Eye blink artifact]]
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		+	'''Notes'''
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 * Sharply contoured transients, clearly distinguishable from and usually interrupt background activities
 * Almost always negative wave, so pointed upwards on the EEG
-* Spike: Duration of <70 milliseconds
+* '''Spike''': Duration of <70 milliseconds
-* Sharp wave: Duration of 70-200 milliseconds
+* '''Sharp wave''': Duration of 70-200 milliseconds
 * No difference in etiology or prognosis between a spike or sharp wave