Actually, there are more than two types of seizures.
They can be generalized, meaning the entire brain is involved: tonic clonic, absence, or atonic. These all involve loss of consciousness, whether for a second, a minute, or a few minutes.
Or they can be focal seizures: Simple focals, as described above, one limited area of the brain is involved with preserved consciousness. Complex focal seizures: Not the whole brain but not limited to such a small area, the seizure does spread, often but not always staying in one lobe or one side of the brain, these involve altered consciousness or loss of consciousness. Certain complex focals will involve the person appearing to be awake, they may even keep walking, but the movements look a bit odd, and responses will be off or nonsensical. Like the simple focals, what is experienced and or seen by others depends upon the path the seizure takes in the brain.
There are myoclonic seizures, where a limited muscle group is involved in repeated jerking or twitching, this is usually both sides, but can be one side. Consciousness is preserved during myoclonic seizures.
Then there are secondary generalized seizures, which begin as complex focals and spread to the entire brain.
Simple focals do not impact memory. Complex focals and generalized seizures usually do. Complex focals & tonic clonics often involve a recovery period, called post-ictal, where the person who has had the seizure sleeps a particularly deep, hard sleep immediately afterwards. This could be a few minutes or a few hours.
People may have more than one seizure type, but generally, people with epilepsy have typical seizures, ie:what is seen and experienced for their aura will be the same, or one of two or three every time, their seizures will present the same/similar every time.
If you have questions specific to your story, feel free to ask.
***Get the seizure response/first aid right!!! If you write a scene where someone having a seizure is held down or something is stuck in their mouth, you will be faced with the wrath of everyone who has & or loves someone with epilepsy.
Those are very old school movie responses that are dangerous to both the person seizing and the person trying to help them. Seizures are generally self-resolving, meaning they end on their own in 30 seconds-3 minutes (absence, atonic, and myoclonic are shorter, just a second or a few, but often occur in clusters). Seizures lasting more than 5 minutes are a medical emergency called status epilepticus.
Seizure First Aid: Stay with the person having the seizure. Stay calm. Move anything they might harm themselves on through jerking/falling. If they are still up and moving but near stairs/water/ subway tracks, guide them away from the danger, try to help them/encourage them to sit--do NOT force. If wearing a tie or scarf, try to loosen it. If they have fallen/lost consciousness, gently turn them on their side. They will NOT, I repeat, NOT swallow their tongue, physically impossible, however, it is possible when all the muscles relax for the tongue to block their airway, or excessive saliva to pose a choking hazard. Turning them onto their side prevents this. Time the seizure, if longer than 5 minutes, call 911. If people begin gathering, encourage them to step back, 1) this is not a show, 2) people with epilepsy often come out of the seizure confused, sometimes agitated, a crowd of people on top of them is frightening.
