Generalised seizures occur when the whole brain is affected by abnormal electrical activity. The young person becomes unconscious, if sometimes only briefly.
Focal seizures occur when one area (or lobe) of the brain is affected by abnormal electrical activity. The symptoms and level of consciousness depend on the area of the brain involved.
These seizures are described according to how they present, particularly whether they cause changes in movement (motor symptoms) or sensation (sensory symptoms) for the young person. What the seizure looks like depends on where in the brain it comes from and what function that area is responsible for. There may be some impairment of consciousness with these seizures although sometimes the young person may be fully aware throughout. Focal seizures can spread to affect the whole brain, resulting in a generalised seizure.