These seizures originate in a particular region rather than across the whole brain. There are two subtypes of partial seizures:
- these seizures do not impair consciousness
- symptoms depend on the origin of the seizure
Simple partial seizures originating in the frontal lobe (the “motor” cortex) typically result in rhythmic movements in the arms and legs – twitches.
Simple partial seizures originating in the occipital lobe (the “visual” cortex) typically produce the experience of visual hallucinations.
Simple partial seizures originating in the parietal lobe (the “somatosensory” cortex) typically cause strange physical feelings, such as a tingling or warm feeling down one side of the body.
Simple partial seizures originating in the temporal lobe (the “auditory”, “taste/smell” or “memory” cortex) may cause a number of different experiences such as a churning feeling in your stomach, smelling non-existent smells, tasting non-existent tastes, feelings of fear, panic, sadness or happiness, and feelings of ‘deja vu’.
These seizures do impair consciousness, so the individual may not be aware that they have had a seizure and may not have a memory of the event.
In these seizures the electrical disturbance begins in a focal region of the brain but quickly spreads to other brain regions so that it becomes a generalised seizure.
This type of seizure involves synchronised electrical activity right across the brain which usually results in the loss of consciousness.
These are the most common form of generalised seizure. This occurs in two phases: the tonic first, followed by the clonic stage. In the tonic stage, the individual becomes stiff as their muscles contract. The muscles in the lungs contract making breathing difficult and often results in the skin turning blue due to a lack of oxygen in the blood. The clonic stage involves jerking movements as the muscles relax and contract in turn. During this phase the individual may bite their tongue and become incontinent. Over time, these contractions become less frequent until they eventually stop. This type of seizure typically lasts less than a minute though it may seem much longer as the episode is so frightening.
This type of seizure typically occurs in children. The child appears to stare blankly and seems to be daydreaming; however, you are temporarily unconscious and are inaccessible.
These seizures may affect the whole body but most typically affect one or both arms and sometimes the head; the seizure causes jerking which can be severe enough to make you fall over.
The individual becomes stiff as their muscles contract and the individual often falls to the ground. The muscles in the lungs also contract making breathing difficult and can result in skin turning blue due to a lack of oxygen in the blood.
These are often called “drop attacks” and are caused by the sudden but complete loss of muscle tone; this results in an instantaneous collapse to the ground. The individual is usually able to get up straightaway, as the seizure is very brief but you are at high risk of injuring your head as you fall.