The exact cause of mesial temporal sclerosis is still unclear. Some cases can result from injury to this part of the brain from prolonged febrile seizures. In other cases, a genetic susceptibility can play a role as well especially in cases where family members have had similar seizures.
In children with newly diagnosed epilepsy, only approximately 1% have evidence of Mesial Temporal Sclerosis on imaging.
Furthermore, in adults 3-10% of cases of mesial temporal sclerosis demonstrate bilateral changes even though symptoms may be unilateral.