What does a spike look like on an EEG?
Spikes are very fast waves and are called spikes because of their shape on the EEG. Each lasts less than 80 milliseconds (less than 1/12th of a second) and may be followed by slow delta waves. Spikes clearly stand out from other brain activity on the EEG.
What are discharges on EEG?
Interictal epileptic discharges (IEDs), including sharp waves, spikes, and spike–wave complexes, are paroxysmal waveforms seen in the electroencephalogram (EEG) of people with epilepsy.
What are epileptiform spikes?
Epileptiform transients such as spikes and sharp waves are the interictal marker of a patient with epilepsy and are the EEG signature of a seizure focus. Nonepileptiform abnormalities are characterized by alterations in normal rhythms or by the appearance of abnormal ones.
What does 3 Hz spike and wave mean?
The following patterns of interictal epileptiform discharges may be seen: 3 Hz and spike-wave: These are typical for absence seizures but can also occur in other types of generalized seizures. The waking background EEG activity is normal.
What causes epileptic discharge?
The most common cause of PLEDs is an acute or subacute structural injury of the cerebral cortex, either diffuse or focal; however, PLEDs may also be seen in patients with a chronic static cerebral lesion or chronic epilepsy.
What is a spike and wave pattern on an EEG?
Spike-and-wave is a pattern of the electroencephalogram (EEG) typically observed during epileptic seizures. A spike-and-wave discharge is a regular, symmetrical, generalized EEG pattern seen particularly during absence epilepsy, also known as ‘petit mal’ epilepsy.
What are spikes and sharp waves in a seizure?
Spikes and sharp waves. 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%.
How are absence seizures characterized on EEG?
Typical absence seizures are described by generalized spike-and-wave patterns on an EEG with a discharge of 2.5 Hz or greater. They can be characterized by an increase in synchronization of discharges in the thalamocortical circuitry. They can also be characterized by the acute onset and termination of the seizure.
What is the difference between a spike and a sharp wave?
Spikes and sharp waves 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
