CHARACTERISTICS OF MEDIAL TEMPORAL-LOBE EPILEPSY - .1. RESULTS OF HISTORY AND PHYSICAL-EXAMINATION

In order to more precisely define a syndrome of medial temporal lobe e pilepsy, histories and physical findings were evaluated in 67 patients studied with intracranial electrodes who had medial temporal seizure onset and became seizure free following temporal lobectomy. Patients w ith circumscribed, potentially epileptogenic mass lesions were exclude d. Fifty-four patients (81%) had histories of convulsions during early childhood or infancy, 52 of which were associated with fever. Complic ated febrile seizures occurred in 33 (94%) of the 35 patients in whom detailed descriptions of the febrile seizures were available. Bacteria l (5) or viral (2) central nervous system infections were present in 7 patients with seizures and fevers. Other less common, but probably si gnificant, risk factors included head trauma (10%) and birth trauma (3 %). Only 5 patients had no apparent risk factors. The mean age at habi tual seizure onset was 3 years. All patients had complex partial seizu res, with half having only complex partial seizures. The other half al so had secondarily generalized tonic-clonic seizures, but these were n ever the predominant seizure type. Only 3 patients had histories of co nvulsive status epilepticus and no patient had a history of nonconvuls ive status epilepticus. All but 3 patients reported auras before some or all of their seizures, with an abdominal visceral sensation being b y far the most common type of aura (61%). Of the 60 patients with iden tified risk factors, all but 2 had an interval between the presumed ce rebral insult and the development of habitual seizures, with a mean se izure-free interval of 7.5 years. Fifteen patients developed a seizure -free interval following onset of habitual seizures, with a mean durat ion of 5.9 years. In 22 patients, the seizures had an evolutionary pat tern, with seizures becoming progressively more elaborate over time. W e conclude (1) there is a very strong relationship between complicated febrile seizures during early childhood or infancy and the later deve lopment of medial temporal lobe epilepsy; (2) habitual seizures in mos t patients from this population begin during, or shortly after, the fi rst decade of life; (3) complex partial seizures are seen in all such patients; (4) generalized tonic-clonic seizures are not a predominant seizure type in these patients, and convulsive status epilepticus is u ncommon; (5) nonconvulsive status epilepticus rarely, if ever, occurs in these patients; (6) auras, particularly abdominal visceral sensatio ns, are very common; and (7) medial temporal lobe epilepsy can be a pr ogressive disease as evidenced by silent intervals and progressive ela boration of seizures.