What features distinguish focal from generalized onset seizures
Focal seizures start in a specific area of the brain and have clinical and electrographic features that indicate onset from a single unilateral brain region.
Generalized seizures appear to arise from both cerebral hemispheres at once.
The manifestations of focal seizures depend on the area of the brain involved. Consciousness is likely to be impaired if the focal seizure involves the limbic system or a sufficiently large region of the brain.
Focal seizures may then spread to adjacent areas or to contralateral or other more distant regions through thalamocortical and interhemispheric pathways, eventually resulting in secondarily generalized seizures.
