Focal epilepsy is a neurological condition in which the predominant symptom is recurring seizures that affect one hemisphere (half) of the brain.
- Focal epilepsies are characterized by seizures arising from a specific part (lobe) of the brain.
- Focal epilepsies include idiopathic location-related epilepsies (ILRE), frontal lobe epilepsy, temporal lobe epilepsy, parietal lobe epilepsy and occipital lobe epilepsy.
- Focal epilepsy may be treated with medication, and occasionally with diet, nerve stimulation or surgery, especially if the condition is due to a scar or other lesion in the brain.
Idiopathic Localization-Related Epilepsies (ILRE)
The cause of these localized (focal) seizures is not yet known, but some research points to a genetic component. The person’s brain and brain function may appear normal.
Treatment for these epilepsies starts with anticonvulsant medications. Epilepsy surgery such as laser ablation or temporal lobectomy may be an option, especially when the cause of the seizures is an abnormality in the brain such as mesial temporal sclerosis.
Frontal Lobe Epilepsy
Frontal lobe epilepsy is the term for recurring seizures beginning in the frontal lobe — the area of the brain behind the forehead. Because the frontal lobe is responsible for planning and executing movement and personality, frontal lobe epilepsy can have a dramatic effect on a patient’s quality of life.
Frontal lobe seizures are often very brief (less than 30 seconds) and tend to occur at night. They are typically simple or complex partial seizures and can quickly spread throughout the brain. Because there are so many connections between the frontal and temporal lobes, it can be difficult to determine which section of the brain is being affected.
Anticonvulsant medications are the most common first choice for treatment; if these do not control the seizures, surgery may be an option.
Temporal Lobe Epilepsy
Temporal lobe epilepsy is the term for recurring seizures beginning in the temporal lobe – the section of the brain located on the sides of the head behind the temples and cheekbones.
The temporal lobes are the areas of the brain that most commonly give rise to seizures. The mesial portion (middle) of both temporal lobes is very important in epilepsy — it is frequently the source of seizures and can be prone to damage or scarring.
Because there are so many diverse functions either in or closely related to the temporal lobes, these seizures may have a dramatic effect on the patient’s quality of life.
Seizures beginning in the temporal lobes may remain there, or they may spread to other areas of the brain. Depending on if and where the seizure spreads, the patient may experience the sensation of:
A peculiar smell (such as burning rubber)
Strong emotions (such as fear)
Automatic, unconsciously repeated movements
Loss of awareness
Parietal Lobe Epilepsy
The parietal lobe is the section of the brain on the top and sides of the head. Known as the “association cortex,” the parietal lobe is responsible for connecting meaning to the brain’s functions. It is here that the brain creates a visual image, that sounds are recognized as words, and that the sense of touch is associated with a particular object. In some ways, the parietal lobe is where perception meshes with physical reality.
Parietal lobe epilepsy is very uncommon. Seizures starting in this area can cause sensory disturbances, such as heat, numbness or electrical sensations, weakness, dizziness, hallucinations, distortions of space and other symptoms.
Occipital Lobe Epilepsy
Occipital lobe epilepsy is the term for recurring seizures beginning in the occipital lobe, the section of the brain in the back of the head that is primarily responsible for vision. Seizures beginning in the occipital lobe are rare.
These seizures can cause a person to experience flashing bright lights or other visual changes on the left side of his or her visual field (if occurring in the right cortex), or on the right side (if occurring in the left cortex).