Familial Temporal Lobe Epilepsies
Specialists currently recognize dozens of epilepsy syndromes. These syndromes differ from one another for many reasons such as when the seizures begin, what kind of seizures they cause, and where the seizures occur in the brain. Temporal lobe epilepsy (TLE) is the most common kind of focal epilepsy.1
Types of TLE
Focal epilepsies only affect 1 area of the brain, such as the temporal lobe in TLE. The brain has 2 of these lobes. They are on opposite sides of the head, over your ears. There are 2 types of TLE, mesial temporal lobe epilepsy (MTLE) and lateral temporal lobe epilepsy (also known as neocortical temporal lobe epilepsy).1
MTLE involves the part of the temporal lobe that is closer to the inside of the brain. It often involves the hippocampus, or the memory center of the brain. It accounts for almost 80 percent of TLE.1
TLE usually begins between the ages of 10 and 20. It often occurs in someone who had a seizure with a high fever as a child or a brain injury at a young age. It affects all sexes equally. Though these seizures may be frustrating at times, TLE does not affect brain development or function.1,2
Familial disorders are those that are passed down through families. They are caused by DNA changes (mutations) or specific genes. Familial TLE is an autosomal dominant condition. This means that if 1 of your parents is living with TLE, it is highly likely that it will be passed to you.2
However, TLE is said to have incomplete penetrance. This means that some people who carry the gene will not experience seizures.2
What seizures does TLE cause?
TLE seizures are generally mild and do not happen often. They mostly affect your cognition or thinking. They usually present with visual or auditory illusions, hallucinations, or the feeling of déjà vu. They can also present as unexpected emotions like fear. They can also cause numbness or tingling sensations.2
Rarely, a focal seizure can progress to a tonic-clonic seizure. During these seizures, you lose consciousness. Then your muscles become stiff and you might experience muscle jerking. Those living with lateral TLE are more likely to experience these tonic-clonic seizures.2,3
How is TLE diagnosed?
After your doctor takes a thorough history of your seizures, they will likely order an electroencephalogram (EEG) to look at your brain activity. They also may order an imaging study like an MRI (magnetic resonance imaging). Many people with TLE have normal MRI results. However, for some people, an MRI may show scarring in the temporal lobe. The hippocampus might also look smaller on 1 side or both.1
How is TLE treated?
Anti-seizure medications can completely control seizures in around two-thirds of those living with TLE. However, if an MRI shows scarring, anti-seizure medications likely will not work to stop the seizures. Your doctor may recommend surgery to remove the scar.1
If you are considering surgery, it is important to do neuropsychological testing first. This looks at brain functions like attention, memory, speech, and learning. This testing will help your doctor decide if surgery is right for you.1
Comorbidities of TLE
Comorbidities refer to other disorders that are more likely when you are diagnosed with a specific disease. Unfortunately, those living with TLE are more likely to live with other psychiatric disorders such as anxiety and depression. This is especially true in children. It can affect their quality of life and how they learn. TLE may also be more common in children living on the autism spectrum.3
If you believe that you or a loved one may be experiencing TLE, speak to your doctor.