Partial or focal epilepsy syndromes are described in terms of the part of the brain they involve (the seizure focus). Many partial seizures arise in the temporal lobe. However, seizures can also arise in other lobes of the brain. These are called extratemporal seizures. Symptomatic seizures are most common, but others include idiopathic and cryptogenic seizures.
About 60 per cent to 80 per cent of extratemporal partial seizures are symptomatic; the two most common causes of extratemporal seizures are brain tumours and congenital malformations. For this reason, a child with partial seizures will be assessed carefully and may be given an MRI or a CT scan to locate the problem.
Depending on the cause of the seizures, the child may be treated with anti-epileptic drugs and/or surgery.
Frontal lobe epilepsy
Frontal lobe epilepsy is nearly as common as temporal lobe epilepsy. The motor cortex is located in the frontal lobe, so partial motor seizures are an example of frontal lobe epilepsy. These usually involve twitching of the face that may spread to the arm and leg on the same side of the body.
Seizures can also begin elsewhere in the frontal lobe, and these have different symptoms. It can be difficult to identify a frontal lobe seizure, because they often become secondarily generalized very fast.
Frontal lobe seizures usually begin and end quickly, and often happen at night. A child with this type of seizure may have many brief seizures, often in clusters of several seizures. They may turn their eyes and head to one side or raise one arm, and may cry out. Status epilepticus is common in frontal lobe epilepsy.
There are few well-defined frontal lobe seizure syndromes. One syndrome that has been identified is autosomal dominant nocturnal frontal lobe epilepsy, a rare syndrome with a strong genetic basis.
Parietal lobe epilepsy
Parietal lobe epilepsy is quite rare. The sensory cortex is located in the parietal lobe, so partial somatosensory seizures are an example of parietal lobe epilepsy. Most seizures that begin in the parietal lobe start with a somatosensory aura, such as tingling and numbness. Some people may feel pain in the affected area, or may feel that one hand or foot is moving or is not there. Parietal lobe epilepsy is often caused by a tumour in the parietal lobe.
Occipital lobe epilepsy
Occipital lobe epilepsy is also rare. Children with occipital seizures often see flashing lights or simple shapes that are not there, or may not be able to see anything during the seizure. In rare cases, a child may have complex visual hallucinations, such as seeing a face. The child’s eyes and head may turn to one side.
Some idiopathic occipital lobe epilepsy syndromes have been identified, including early- and late-onset childhood epilepsy with occipital spikes or paroxysms (BECOS) and idiopathic photosensitive occipital epilepsy.
Early-onset benign childhood occipital epilepsy is sometimes called Panayiotopoulos syndrome. Children with this syndrome start having seizures when they are between two and eight years old. The seizures happen at night. The child may vomit and their eyes may turn to one side. The child’s arms and legs may move, and the seizures may become secondarily generalized.
In late-onset or Gastaut type childhood occipital epilepsy, the seizures begin when the child is a teenager. They usually begin with visual symptoms, such as blindness or seeing flashing lights or shapes that are not there, and may progress to unusual movements or behaviour. The child often has a headache after the seizure. They may feel nauseated or vomit.
Epilepsy involving more than one lobe of the brain
Finally, seizures often affect regions of the brain where two lobes meet. This can result in signs and symptoms that are different than those seen in the pure forms of partial epilepsy.
Hemiconvulsion-hemiplegia syndrome
This syndrome is also known as hemiconvulsions, hemiplegia, and epilepsy syndrome, HH syndrome, or HHE syndrome. It begins with an episode of status epilepticus when a child is between six months and two years old. The child has convulsions on one side of the body, which may last from an hour to several days. Afterwards, the child has weakness on one side of the body; this may or may not go away. Months or years later, the child has partial motor or complex partial seizures beginning on the side of the brain that was originally affected. These may become secondarily generalized.
Because the treatment of status epilepticus has improved, this syndrome is now comparatively rare.