Surface and depth EEG findings in patients with hippocampal atrophy

King, David; Spencer, Susan S.; McCarthy, Gregory; Spencer, Dennis D.

doi:10.1212/wnl.48.5.1363

Cited by 53 publications

(36 citation statements)

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“…MRI and EEG, however, are clearly not independent predictor variables and do not have a simple association with surgical outcome (29). Our findings do not diminish the importance of ictal EEG recording to define the epileptogenic region more clearly in patients without concordant unilateral MRI and interictal EEG abnormalities and definitive clinical evidence of MBTLE.…”

Section: Discussioncontrasting

confidence: 56%

“…The sensitivity of interictal EEG in these studies ranged from 25% to 95%. Similarly, MRI has been found to identify mesial temporal atrophy or signal abnormality in the majority of temporal lobectomy candidates, predicting surgical success in >SO% of selected patients in some series (3,7,29). The largest, most detailed study, however, reported a seizure-free rate of 62% in patients with MRI evidence of unilateral MTS (10).…”

Section: Discussionmentioning

confidence: 99%

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Association of Combined MRI, Interictal EEG, and Ictal EEG Results with Outcome and Pathology After Temporal Lobectomy

et al. 1997

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Summary:Purpose: Magnetic resonance imaging, interictal scalp EEG, and ictal scalp EEG each have been shown to localize the primaly epileptic region in most patients with mesial-basal temporal lobe epilepsy (MBTLE), but the association of surgical outcome and pathology with each combination of these test results is not known.Methods: We reviewed the MRI, interictal scalp EEG, and ictal scalp EEG results of 90 consecutive patients with MBTLE. Twelve patients were excluded from the analysis because inconclusive bitemporal intracranial EEG results precluded anterior temporal lobectomy (ATL); none had concordant MRI and interictal scalp EEG results. We compared all combinations of presurgical MRI, interictal EEG, and ictal EEG results to seizure outcome and tissue pathology in the 78 patients who underwent an ATL.Results: Forty-eight (6 1 %) patients had concordant lateralized MRI and interictal EEG temporal lobe abnormalities, with no discordant ictal EEG results; 77% of these patients were seizure-free after ATL. Concordance of MRI and interictal EEG abnormalities correlated with seizure cessation (p < 0.05), compared to all combinations with discordant or nonlateralizing MRI and interictal EEG results. Mesial temporal sclerosis (MTS) was confirmed pathologically in about 80% of both groups (p = 0.5). Outcome in patients with concordant MRI and ictal EEG with nonlateralizing interictal EEG was significantly worse than combinations with concordant MRI and interictal EEG (p < 0.02). Mesial-basal temporal lobe epilepsy (MBTLE) is a common syndrome that often remains resistant to drug therapy. Anterior temporal lobectomy (ATL), therefore, is the most frequently performed epilepsy surgery worldwide (1). Most epilepsy centers require an intensive presurgical assessment using neuroimaging tests and longterm, inpatient video/EEG monitoring to confirm the brain region of seizure onset (2). Prior investigations have demonstrated that MRI (3-lo), interictal EEG (1 1-19), and ictal EEG (8,9,20) anterior temporal epileptiform EEG abnormalities is associated with successful surgery, but detailed analysis of the pathology and outcome associated with each combination of MRI, interictal EEG, and ictal EEG result has not been reported previously. ConclusionsWe reviewed retrospectively results of the MRI, interictal scalp EEG, and ictal scalp EEG of 90 consecutive patients evaluated for possible ATL to determine the association of all observed combinations of test results with surgical outcome. We also compared each combination of test results to resected tissue pathology to determine the association with mesial temporal sclerosis. METHODS PatientsWe evaluated a cohort of 90 consecutive patients who had historical and routine EEG or MRI evidence of tem- 1315

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Section: Discussioncontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Association of Combined MRI, Interictal EEG, and Ictal EEG Results with Outcome and Pathology After Temporal Lobectomy

et al. 1997

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“…Although hippocampal atrophy was encountered in most patients with successful outcome in our study, it was also seen in 17 of 23 patients who continued to have seizures. A high association of hippocampal atrophy with good surgical outcome has been repeatedly reported (8- 1 2 ) , but studies also indicated that hippocampal atrophy does not necessarily lateralize (34) or localize epileptogenicity only to the mesial structures (9,34). These studies suggest the presence of a more extensive pathology in some patients.…”

Section: Discussionmentioning

confidence: 99%

Visual and Quantitative Ictal EEG Predictors of Outcome After Temporal Lobectomy

Assaf

Ebersole

1999

Epilepsia

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Summary: Purpose; We investigated whether visual and quantitative ictal EEG analysis could predict surgical outcome after anteromesial temporal lobectomy (AMTL) in which mesial structures, basal, and temporal tip cortex were resected.Methods: We retrospectively reviewed 282 presurgical scalprecorded ictal EEGs (21-to 27-channel) from 75 patients who underwent AMTL. We examined the pattern of seizure onset (frequency, distribution, and evolution) and estimated the principal underlying cerebral generators by using a multiple fixed dipole model that decomposes temporal lobe activity into four sublobar sources (Focus 1.1). We correlated findings with a 2-year postoperative outcome.Results: Sixteen patients had seizures with a well-lateralized, regular 5 to 9-Hz rhythm at onset, that most often had a temporal or subtemporal distribution. All patients became seizure free after surgery. In 5 I patients, seizure onset was remarkable for lateralized slow rhythms (<5 Hz), which sometimes appeared as periodic discharges, were often irregular and stable only for short periods (<5 s), and had a widespread lateral temporal distribution. Among these a favorable surgical outcome was encountered in patients with seizures having prominent anterior-tip sources (16 of 17 seizure free), whereas those with dominant lateral or oblique sources had a less favorable outcome (three of 14 and 13 of 18, respectively). Irregular, nonlateralized slowing characterized seizure onsets in eight patients. Three patients became seizure free after surgery.Conclusions: Both visual and quantitative sublobar source analysis of scalp ictal EEG can predict surgical outcome in most cases after AMTL and complement non-invasive presurgical evaluation.

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“…Even in this group, however, hippocampal atrophy was 75% sensitive to, and 64% specific for, ipsilateral medial temporal lobe seizure onset recorded by depth electrodes. In another study of an unselected consecutive group of 1 19 patients with refractory epilepsy, all of whom had HA, only 50% had sufficient convergence of different localizing studies to have surgery on the medial temporal lobe (48). Four patients in this group with concordantly localized ictal onset and HA failed to achieve seizure control after resection of that hippocampus, and three patients with ictal localization to the hippocampus opposite the atrophic one became seizure-free after removal of the nonatrophic, but electrically abnormal, hippocampus.…”

Section: Developmental Acquired Medial Temporal Lobe Epilepsy Localmentioning

confidence: 98%

Substrates of Localization‐Related Epilepsies: Biologic Implications of Localizing Findings in Humans

Spencer

1998

Epilepsia

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Surface and depth EEG findings in patients with hippocampal atrophy

Abstract: The presence of HcA is not an independent predictor of the site of epileptogenesis.

Cited by 53 publications

References 0 publications

Association of Combined MRI, Interictal EEG, and Ictal EEG Results with Outcome and Pathology After Temporal Lobectomy

Association of Combined MRI, Interictal EEG, and Ictal EEG Results with Outcome and Pathology After Temporal Lobectomy

Visual and Quantitative Ictal EEG Predictors of Outcome After Temporal Lobectomy

Substrates of Localization‐Related Epilepsies: Biologic Implications of Localizing Findings in Humans

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