Mild Non-lesional Temporal Lobe Epilepsy: A Common, Unrecognized Disorder with Onset in Adulthood

Abstract

ABSTRACT:Objective:To compare mild vs. severe non-lesional temporal lobe epilepsy (TLE).Methods:Data from 104 consecutive patients with non-lesional TLE were reviewed. Seventy-three of the 104 fulfilled the criteria for inclusion in this study of a follow-up period longer than three years at our Institute. Patients were considered to have a mild TLE if they were seizure free for at least three years after appropriate antiepileptic medication, or had rare (≤ 2/year) complex partial or secondarily generalized seizures for at least three years with or without appropriate antiepileptic therapy. Clinical, EEG and MRI data of mild vs. severe non-lesional TLE patients were compared on the basis of a cross-sectional study design.Results:Of the 73 patients with non-lesional TLE included in the study, 43 (59%) had mild TLE, and 30 (41%) had severe TLE. Duration of epilepsy was significantly shorter (mean 15.2 ± 10.5 years vs. 26.4 ± 13.2 years) and age at onset was significantly higher (mean 34.3 ± 15.3 years vs. 7.8 ± 6.8 years) in mild than in severe TLE group. Patients with mild TLE had also a significantly higher prevalence of positive family history of epilepsy (37.2% vs. 10%), and a significantly lower occurrence rate of febrile convulsions (FC) (4.7% vs. 33.3%), mesial temporal sclerosis (MTS) (6.9% vs. 36.7%), and intelligence deficiency (0% vs. 20%). In mild TLE there was also a significantly high rate (58.1% vs. 0%) of delayed diagnosis (from 1 to 28 years), because of misdiagnosis (39.5%) or no medical counseling (18.6%).Conclusions:Mild non-lesional TLE is a common, unrecognized disorder mainly characterized by both onset in adulthood and high prevalence of familial history of epilepsy. The present findings suggest that mild non-lesional TLE may represent a clinical entity different from severe non-lesional TLE.

Hippocampal and thalamic atrophy in mild temporal lobe epilepsy

“…Since 1998, our group has focused on studying patients with mild drug-responsive TLE. 18,19 We showed recently that nearly 40% of our patients with mild TLE have MRI detectable MTS. 20 Afterwards, other studies further supported our observation.…”

Age at onset predicts good seizure outcome in sporadic non-lesional and mesial temporal sclerosis based temporal lobe epilepsy

“…Conversely, non-lesional TLE represents the most common subtype and comprises patients with mesial temporal sclerosis (MTS) 4 5. It is a heterogeneous disorder as there are patients with a severe refractory form while many others have a mild epileptic disorder and they enter remission with or without antiepileptic medication 5 6. Indeed, in this type of epilepsy the prediction of the clinical course would help both physicians and patients.…”

Did Herbert Spencer Have Reading Epilepsy?

“…Interestingly, a study of individuals affected by one of the recently characterized hereditary temporal lobe epilepsies found a mean age of onset of 34.3 years (Aguglia et al, 1998). Another feature of Spencer's illness suggests a possible affiliation to one of the hereditary partial epilepsies.…”

“…The very subtlety of his condition, with likely limitation to a psychological aura and, over time, full preservation of intellectual function, is reminiscent of some (but not all) cases within the recently delineated partial epilepsies. (A number of these individuals escaped neurological attention for a lengthy period because they were viewed as suffering from panic attacks or other neuroses [Aguglia et al, 1998]). In any event, both in abruptness and in relative lateness of onset, Spencer's disorder points to an organic rather than a psychogenic condition and, as regards the former category, is not uncharacteristic of a relatively subtle partial (temporal lobe) seizure disorder.…”

“…(In fact, as reported elsewhere, at least one of his friends alluded covertly to his suffering from epilepsy [Raitiere, 2008;Raitiere, forthcoming]). But even in our day, epilepsies at the benign end of the spectrum have gone undiagnosed for up to 28 years (Aguglia et al, 1998; median elapsed time prior to correct diagnosis was 10.5 years); a fortiori, a condition that was not formally characterized as epileptic until 1956 bore an extremely high likelihood of being dismissed as "psychoneurotic" before then (as noted by an auditor of the original American report; see Bickford et al, 1956, p.102). Largely negative evidence from Spencer's nineteenth-century contemporaries therefore counts for little in the discussion.…”