Temporal lobe epilepsy (TLE) is a type of epilepsy that originates in the temporal lobe region of the brain. Each person has two temporal lobes located on either side of the head behind the temples, in alignment with the eyes. These lobes play a role in processing emotions and are important for short–term memory. Symptoms of a temporal lobe seizure often relate to these functions. During such seizures, individuals may experience unusual sensations like joy, déjà vu, or fear.
Temporal lobe seizures are also known as focal seizures with impaired awareness. While some people remain conscious and aware of their surroundings during the seizure, others may appear awake but are unresponsive. They may exhibit repetitive movements with their lips and hands.
There are two main types of TLE:
- Mesial temporal lobe epilepsy (MTLE): Approximately 80% of all temporal lobe seizures originate in the mesial temporal lobe, often in or near a structure called the hippocampus. Each temporal lobe contains a hippocampus, which is responsible for memory and learning. MTLE is the most common form of epilepsy.
- Neocortical or lateral TLE: This type of TLE is rare and occurs when seizures begin in the outer section of the temporal lobe. It is typically associated with genetic causes or abnormalities such as tumors, birth defects, blood vessel irregularities, or other issues in the temporal lobe.
The exact cause of temporal lobe seizures is often unknown. However, it can sometimes be attributed to scarring in the temporal lobe. Treatment for temporal lobe seizures usually involves medication. In cases where medication is ineffective, surgery may be considered as an option.
Auras can occur before temporal lobe seizures, serving as an unusual sensation that acts as a warning. However, not all individuals experiencing temporal lobe seizures have auras, and even if they do, they may not remember them. Auras manifest as various experiences such as sudden fear or joy, a sense of déjà vu, peculiar smells or tastes, or a rising sensation in the belly resembling a roller coaster ride. Occasionally, temporal lobe seizures can hinder one’s responsiveness to others, typically lasting from 30 seconds to 2 minutes.
The symptoms of a temporal lobe seizure may include the following:
- Lack of awareness or consciousness of one’s surroundings.
- Staring into space.
- Repetitive lip smacking.
- Frequent swallowing or chewing movements.
- Finger movements, such as picking motions.
Following a temporal lobe seizure, individuals may experience the following:
- A period of confusion and difficulty with speech.
- Inability to remember the events that took place during the seizure.
- Lack of awareness of having experienced a seizure.
- Profound drowsiness or excessive sleepiness.
Occasionally, a temporal lobe seizure can progress into a generalized tonic–clonic seizure, characterized by rigidness and shaking of the entire body accompanied by a loss of consciousness. This type of seizure impacts both hemispheres of the brain and is commonly referred to as a convulsion. Symptoms may include loss of bladder control or unintentional biting of the tongue. Previously, this condition was known as a grand mal seizure.
If any of the following situations occur, it is advisable to immediately call emergency services:
- If the seizure lasts longer than five minutes.
- If breathing or consciousness does not return after the seizure stops.
- If a second seizure occurs immediately after the first.
- If complete recovery does not occur after the seizure.
- If recovery is slower than usual after the seizure.
- If you have a high fever.
- If you are experiencing heat exhaustion.
- If you are pregnant.
- If you have diabetes.
- If you have sustained an injury during the seizure.
If you experience a seizure for the first time, it is recommended to seek medical attention from a healthcare provider.
Temporal lobe epilepsy can be caused by various factors, including:
- Unknown causes: Approximately 25% of temporal lobe seizures have no identified underlying cause.
- Brain injury: Traumatic events like vehicular accidents, falls, or head blows can lead to temporal lobe epilepsy.
- Infections: Conditions such as encephalitis or meningitis, as well as a history of these infections, can contribute to the development of temporal lobe seizures.
- Gliosis: The scarring process in the hippocampus, a region within the temporal lobe, can cause temporal lobe epilepsy.
- Stroke: A stroke, which disrupts blood flow to the brain, can be a factor in the occurrence of temporal lobe seizures.
- Genetic factors: Genetic mutations or a family history of epilepsy can increase the risk of developing temporal lobe seizures.
- Brain infections: Conditions like brain abscess, meningitis, encephalitis, and acquired immune deficiency syndrome (AIDS) can be associated with temporal lobe epilepsy.
- Brain conditions and vessel abnormalities: Abnormalities such as brain tumors, strokes, dementia, and abnormal blood vessels like arteriovenous malformations can contribute to the occurrence of temporal lobe seizures.
- Mesial temporal sclerosis: This refers to the scarring (sclerosis) of brain cells in the temporal lobe, particularly the hippocampus. It can lead to temporal lobe epilepsy.
During both wakefulness and sleep, the brain cells generate varying electrical activity. Seizures can occur when there is an abnormal burst of electrical activity in many brain cells. In the case of temporal lobe epilepsy, this abnormal activity originates in one of the temporal lobes, resulting in a focal seizure.