Focal seizures are the most common seizures experienced by adults with epilepsy. If the seizure begins in one hemisphere of the brain and the person is not responsive or is confused or there is a change in their level of awareness during some or all of the seizure it is known as a focal impaired consciousness seizure.

The seizures usually originate in the temporal or frontal lobe on one side of the brain, although other areas can be affected. Those beginning in the temporal lobe tend to last longer. Automatisms (involuntary actions with no purpose) are a key feature where people may move their mouth, pick at the air, for example. Sometimes they might just freeze and stare.⁶ 

A focal preserved consciousness seizure begins in one side of the brain, during which a person is responsive, and has no confusion or loss of consciousness of their surroundings. People with focal seizures can experience both types – ones where they are aware and responsive during the seizure and others where their awareness or responsiveness is impaired partly or completely.⁶ 

Focal to bilateral tonic-clonic seizures start in a limited area of one hemisphere of the brain then spread to involve both hemispheres. More than 3 in 10 people with focal epilepsy have this type of seizure. The beginning of the seizure is brief, lasting for seconds, so it may not be remembered by the person experiencing it. The bilateral tonic-clonic phase of the seizure usually lasts no longer than 2 to 3 minutes. People may experience a smell, feeling of nausea or a change in sensation or movement (referred to as an aura) at the beginning of the seizure. Sometimes people may not be aware of what is happening or become confused if the seizure begins with a focal impaired awareness seizure.⁶ 

Focal seizures where people laugh or giggle uncontrollably are known as gelastic seizures. People may feel scared or that they have lost control. Some may feel anxious causing them to laugh inappropriately. Dacrystic seizures are also partial or focal seizures. People who have them make a crying sound and may grimace. These types of seizure start in the hypothalamus at the base of the brain. They affect about 1 in 3 children and start at an average age of about 10 months.⁶