NSCI430 Chapter Notes - Chapter 50: Partial Seizure, Generalised Tonic-Clonic Seizure, Absence Seizure
21 Feb 2017
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Document Summary
Classifications of seizures: may exhibit positive & negative symptoms. Dependent on location & degree damage: focal seizures. Simple partial = no loss of consciousness. Tonic phase rigid extension of extremities. Postictal period: time following seizure before normal levels of consciousness are regained: generalized seizures. Tonic-clonic (grand mal: tonic phase 30 seconds, clonic phase 1-2 minutes, postictal period headache & drowsiness. Typical absence seizure (petit mal: interrupts motor activity, last less than 10 seconds, loss of consciousness, no loss of posture. Eeg readings: alpha waves: relaxed wakefulness. Moderate amp: beta waves: intense mental activity. Frontal areas: theta & delta waves: drowsiness & slow-wave sleep, sharp waves may indicate seizure activity. Seizure focus: epileptiform activity: enhanced excitability of neurons. Altered synaptic connections: phases of focal seizure. Afterhyperpolarization disappears: anti-convulsants: block excitation or enhance inhibition. Cortical circuitry implicated in seizures: thalamocortical pathway. T-type voltage gated calcium channels: subcortical pathway, interhemispheric pathway, secondary generalization: when both hemispheres are involved.
