An analysis of clinical seizure patterns and their localizing value in frontal and temporal lobe epilepsies

Abstract

The differentiation of frontal lobe epilepsy (FLE) and temporal lobe epilepsy (TLE) is a clinical problem of major theoretical and practical importance. Current electroclinical classification is based on retrospective studies of highly selected patients. When applied to the presurgical evaluation of patients, it has poor specificity. The current study adopts a different and prospective approach to the analysis of ictal clinical manifestations and their value in differentiating FLE and TLE. Two hundred and fifty-two patients with partial epilepsy were selected according to criteria of focal abnormality and imaging, ictal EEG or interictal EEG or highly focal clinical pattern. A witnessed seizure description was obtained for each of their habitual seizures and the sequence of manifestations encoded and entered into a statistical cluster analysis to form a clinical classification of the 352 seizures identified, which comprised 14 clinical groups. Neuroimaging abnormalities were measured, using a template technique, and graded 0-3 according to extent of involvement of each region in the lesion, using standard anatomical divisions. A chi 2 analysis of lesion location against seizure type was performed to assess the strength of association of seizure types with specific cerebral regions. The distribution of interictal EEG spikes and ictal EEG onsets were assessed qualitatively. An independent analysis was also performed, comparing clinical seizure manifestations associated with lesions restricted to either frontal or temporal lobes. Of the 14 clinical groups, four were predominantly related to temporal lobe abnormalities: fear/olfactory/gustatory; absence with no focal symptoms; experiential and visual. Within these groups, 45 out of 58 lesional cases involved the temporal lobes (P<<0.001). A minority of seizures in these groups were associated with frontal lesions and these seizures were significantly more likely to involve version/posturing, without an intervening absence phase, than the temporal cases (P<0.001). Two groups were related to perirolandic abnormalities; somatosensory and Jacksonian clonic with 22 out of 24 lesional cases involving this region (P<0.001). Two other groups were related to the frontal lobes; version/posturing and motor agitation. Early focal tonic activity or head turning were associated with lateral premotor lesions (P<0.001) and ictal and interictal EEG showed strong frontal predominance. Seizures characterized by general motor agitation were associated with lesions of the orbitofrontal (eight out of thirteen cases) and frontopolar (six out of thirteen cases) cortices (P<0.001). Location of interictal EEG spikes and ictal EEG onsets were generally consistent with lesion sites and where there were discrepancies, EEG localization tended to be more diffuse than lesion localization, rather than frankly discordant. Analysis of manifestations associated with pure frontal and pure temporal lesions supported the results of the cluster analysis and also showed a significant association of oro-alim...

Morphological Description of Frontal EEG Interictal and Ictal Discharges in an Adult Cohort of 175 Patients

“…The short duration of the seizures observed in this sample agrees with previous observations [3,4,19,30]. Manford et al found that seizures of less than ten seconds with a rapid recovery were more likely to be associated with frontal than temporal lesions [3].…”

Morphological Description of Frontal EEG Interictal and Ictal Discharges in an Adult Cohort of 175 Patients

“…The short duration of the seizures observed in this sample agrees with previous observations [3,4,19,30]. Manford et al found that seizures of less than ten seconds with a rapid recovery were more likely to be associated with frontal than temporal lesions [3].…”

Clinical characteristics of patients with benign nonlesional temporal lobe epilepsy

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Video-EEG Monitoring Differences in Children with Frontal and Temporal Onset Seizures

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Morphological Description of Frontal EEG Interictal and Ictal Discharges in an Adult Cohort of 175 Patients

“…The short duration of the seizures observed in this sample agrees with previous observations [3,4,19,30]. Manford et al found that seizures of less than ten seconds with a rapid recovery were more likely to be associated with frontal than temporal lesions [3].…”

Clinical characteristics of patients with benign nonlesional temporal lobe epilepsy

“……”

Video-EEG Monitoring Differences in Children with Frontal and Temporal Onset Seizures

“……”

“……”

Morphological Description of Frontal EEG Interictal and Ictal Discharges in an Adult Cohort of 175 Patients

“…The short duration of the seizures observed in this sample agrees with previous observations [3,4,19,30]. Manford et al found that seizures of less than ten seconds with a rapid recovery were more likely to be associated with frontal than temporal lesions [3].…”

Clinical characteristics of patients with benign nonlesional temporal lobe epilepsy

“……”

Video-EEG Monitoring Differences in Children with Frontal and Temporal Onset Seizures

“……”

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