Mesial Temporal Lobe Epilepsy

Mesial temporal lobe epilepsy (MTLE) affects the inner part of the temporal lobe manifesting in the hippocampus, parahippocampal gyrus and the amygdala. MTLE is the most common type of epilepsy and is often characterized by the sense of an aura immediately preceding the seizure.

Symptoms

MTLE typically causes seizures that last 30 seconds to two minutes and may include:

• Before the seizure:
  • An aura or far-away look
  • Euphoria
  • Déjà vu
  • Rising sensation in the abdomen
  • Sudden or strange odor or taste
  • Unprovoked fear
• During the seizure:
  • Jerking motion of the fingers
  • Lip smacking
  • A far-away, glazed look
  • Unaware of surroundings
• After the seizure:
  • Depression
  • Memory loss
  • Difficulty speaking
  • Fatigue

Causes

The exact cause of MTLE is unknown, however it is often associated with a family history of epilepsy, prolonged febrile seizure, pediatric trauma or infection.

Diagnosis

• MRI: An MRI uses large magnets, radio waves and a computer to make images of the inside of the body.
• CT scan: This test uses a series of X-rays and a computer to create images of the inside of the body. A CT scan shows more detail than a regular X-ray.
• EEG: This test records the brain's electrical activity through sticky pads (electrodes) attached to the scalp.

Treatment

• Surgery: A cerebral hemispherectomy or laser ablation surgery may be options for patients with MTLE.
  • A cerebral hemispherectomy requires the removal of part of the brain and may leave the patient with permanent motor and cognitive impairment. For young children who receive this surgery, the healthy part of the brain may grow and take over the functions of the resected section. This is known as plasticity.
  • Minimally invasive MRI-guided laser ablation surgery may be an option for some patients. During these procedures, MRI-guided thermal imaging and laser technology destroy lesions in the brain that cause seizures. The laser targets abnormal tissue at the speed of light and with extraordinary precision. This technology is changing the face of epilepsy treatment, providing a minimally invasive and often life-altering option for many epilepsy patients. Texas Children’s Hospital pioneered the procedure and is one of the leading centers in the country performing this type of surgery.
• Diet: The ketogenic diet has also proven helpful in children with MTLE. A ketogenic diet is a type of diet very high in fat and very low in carbohydrates. Enough protein is included to help promote growth. The diet causes the body to make ketones – chemicals made from the breakdown of body fat. The brain and heart work normally with ketones as an energy source. This special diet must be strictly followed. Too many carbohydrates can stop ketosis. Researchers aren’t sure why the diet works, but some children become seizure free when put on the diet. The diet doesn’t work for every child.
• Vagus nerve stimulation (VNS): This treatment sends small pulses of energy to the brain from one of the vagus nerves, a pair of large nerves in the neck. If your child is age 12 or older and has partial seizures that are not controlled well with medicine, VNS may be an option. VNS is performed by surgically placing a small battery into the chest wall. Small wires are then attached to the battery and placed under the skin and around one of the vagus nerves. The battery is then programmed to send energy impulses every few minutes to the brain. When your child feels a seizure coming on, he or she may activate the impulses by holding a small magnet over the battery. In many cases, this will help to stop the seizure. VNS can have side effects such as hoarse voice, pain in the throat or change in voice.
• Deep brain stimulation: This is a nonsurgical treatment wherein a specific region of the brain is stimulated using precise electrical currents with the aim of regulating abnormal activity.