Focal seizures (previously called partial seizures) start in a specific part of the brain in one hemisphere, and may or may not spread to other parts of the brain. Focal seizures are described by whether the person is conscious during the seizure. Focal seizures include:
Focal PRESERVED CONSCIOUSNESS seizures
During these seizures the person is aware and may experience feelings such as déjà vu, an unpleasant smell or taste, or sensations such as ‘butterflies’ or nausea. These seizures may also involve motor activity (such as involuntary and brief jerking of an arm or leg) or autonomic behaviours (such as fiddling with clothing or pointing). These seizures used to be called ‘simple partial seizures’ or ‘focal aware seizures’.
In some cases, this type of seizure can come before another seizure type (e.g. tonic-clonic seizure). A feeling or movement that indicates a bigger seizure is going to happen is sometimes called an ‘aura’, although they are actually part of the seizure.
Focal impaired CONSCIOUSness seizures
During these seizures the person may appear confused and dazed, and may do strange and repetitive actions (such as fiddling with their clothes, making chewing movements with their mouth or uttering unusual sounds). These seizures used to be called ‘complex partial seizures’ or ‘focal impaired awareness seizures’.