Focal seizures begin in one area of the brain. Focal seizures can be simple or complex. Based on the seizure description, physicians may be able to identify in which part of the brain the seizures are originating.

Simple Focal Seizures (Auras)

Simple focal seizures, also known as auras, occur in one area on one side of the brain, but may spread from there. The person does not lose consciousness during a simple focal seizure. Physicians typically break simple focal seizures down into the following four areas, depending on the location in the brain and parts of the body affected:

Motor: A simple focal seizure with motor symptoms will affect muscle activity, causing jerking movements of a foot, the face, an arm or another part of the body. Physicians can diagnose which side of the brain is affected by observing which side of the body experiences symptoms, since the left brain controls the right side of the body and the right brain controls the left.

Sensory: A simple focal seizure may cause sensory symptoms affecting the senses, such as: hearing problems, hallucinations and olfactory or other distortions.

Autonomic: A simple focal seizure with autonomic symptoms affects the part of the brain responsible for involuntary functions. These seizures may cause changes in blood pressure, heart rhythm, or bowel or bladder function.

Psychic: Some simple focal seizures strike parts of the brain that trigger emotions or memories of previous experiences, causing feelings of fear, anxiety, or déjà vu (the illusory feeling that something has been experienced before).

Complex Focal Seizures

Complex focal seizures are often preceded by a simple focal seizure (aura). Patients experiencing a complex focal seizure may stare blankly into space, or experience automatisms (non-purposeful, repetitive movements such as lip smacking, blinking, grunting, gulping or shouting).