Spike-and-wave
Encyclopedia
Spike-and-wave is the term that describes a particular pattern of the electroencephalogram (EEG) typically observed during epileptic seizures
. Spike-and-wave patterns are seen in many types of epilepsy
, and in particular during absence seizures (also called "petit mal" seizures), which are characterized by clear-cut spike-and-wave EEG oscillations. The mechanisms underlying spike-and-wave patterns are complex and involve cerebral cortex and thalamus, the intrinsic properties of the neurons, and the various types of synaptic receptors present in the circuits. In particular, it is thought that a diffuse increase in cortical excitability (either through enhanced excitation or diminished inhibition) can lead to spike-and-wave patterns through thalamocortical loops. In this case, the spike-and-wave patterns can be synchronous over large portions of the entire cerebral cortex (generalized spike-and-wave seizures). A focal increase of excitability can also entrain the thalamocortical system (or part of it) to generate spike-and-wave patterns, and various types of focal seizures
.
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
. Spike-and-wave patterns are seen in many types of epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
, and in particular during absence seizures (also called "petit mal" seizures), which are characterized by clear-cut spike-and-wave EEG oscillations. The mechanisms underlying spike-and-wave patterns are complex and involve cerebral cortex and thalamus, the intrinsic properties of the neurons, and the various types of synaptic receptors present in the circuits. In particular, it is thought that a diffuse increase in cortical excitability (either through enhanced excitation or diminished inhibition) can lead to spike-and-wave patterns through thalamocortical loops. In this case, the spike-and-wave patterns can be synchronous over large portions of the entire cerebral cortex (generalized spike-and-wave seizures). A focal increase of excitability can also entrain the thalamocortical system (or part of it) to generate spike-and-wave patterns, and various types of focal seizures
Focal seizures
Partial seizures are seizures which affect only a part of the brain at onset. The brain is divided into two hemispheres, each consisting of four lobes - the frontal, temporal, parietal and occipital lobes...
.