Mesial Temporal Sclerosis

Mesial temporal sclerosis is closely related to temporal lobe epilepsy, a type of partial (focal) epilepsy in which the seizure initiation point can be identified within the temporal lobe of the brain. Mesial temporal sclerosis is the loss of neurons and scarring of the temporal lobe associated with certain brain injuries.

Brain damage from traumatic injury, infection, a brain tumor, a lack of oxygen to the brain, or uncontrolled seizures causes the scar tissue to form, particularly in the hippocampus, a region of the temporal lobe. The region begins to atrophy; neurons die and scar tissue takes their place. This damage is thought to be a significant cause of temporal lobe epilepsy. In fact, 70 percent of temporal lobe epilepsy patients have some degree of mesial temporal sclerosis. It also appears that the mesial temporal sclerosis can be worsened by additional seizures.

Symptoms

Mesial temporal sclerosis usually results in partial (focal) epilepsy. This seizure disorder can cause a variety of symptoms such as strange sensations, changes in behavior or emotions, muscle spasms, or convulsions. The seizures usually are localized in the brain, but they may spread to become generalized seizures, which involve the entire brain and may cause a sudden loss of awareness or consciousness.

Diagnosis

The changes associated with mesial temporal sclerosis are easily identifiable on a magnetic resonance imaging (MRI) scan.

Treatment

The assessment of the extent of mesial temporal sclerosis is important because it can be a good indicator of the outcome for patients undergoing temporal lobectomy to get rid of their seizures. For this procedure, the part of the brain containing the point at which the seizures start is removed. The best outcomes for the surgery are in patients with mesial temporal sclerosis on one side of the brain. Also, the more of the sclerosis that is removed, the better patients tend to do. While some are reluctant to undergo brain surgery, it should be noted that the removal of sclerotic tissue likely will cause few neurological impairments because the tissue already is damaged. In addition, because seizures can cause mesial temporal sclerosis to spread, it is important to address them before they cause more neurological damage.