Patients with Temporoparietal Ictal Symptoms and Inferomesial EEG Do Not Benefit from Anterior Temporal Resection

Abstract

Summary:Purpose: The role of posterior structural lesions leading to inadequate results after inferomesial temporal resection is well recognized. Here we present poor surgical outcome in six patients with nonlesional intractable epilepsy, well-defined focal anterior and inferomesial temporal epileptic discharges, and posterior temporoparietal symptoms.Methods: We reviewed patient data including scalp video-EEG telemetry, intracranial EEG recording, magnetic resonance imaging (MRI) sequences (1.5 Tesla), and single-photon emission computed tomography (SPECT) findings.Results: Ictal onset was uni-or bilateral diffuse with late preponderance over one temporal, or centrotemporoparietal regions. Four patients had preresection intracranial EEG monitoring, which suggested an epileptogenic zone in the posterior temporal and inferior parietal area in two, in the temporal lobe in one, and was inconclusive in the remaining one, who showed late epileptiform activity in the temporal neocortex. A second intracranial implantation was performed in three of them after a first anterior temporal resection. This led to posterior temporal neocortical localization in two and posterior temporal-inferior parietal localization in one. Including subpial transection, these six patients had one to four operations each, but only limited improvement occurred as a result of surgery in this group of individuals.Conclusions: We conclude that anterior and inferomesial interictal epileptiform temporal discharges and at times even intracranial EEG monitoring may be misleading. Anteromesial temporal resection is ineffective in patients with posterior temporoparietal clinical ictal features.

Parietal lobe epilepsy: the great imitator among focal epilepsies

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non‐lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al , 2004).…”

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non-lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al, 2004). Synchronous or at least temporal overlapping activation of 10-20 cm 2 of gyral cortex is sufficient to produce scalp EEG spikes in the temporal lobe (Tao et al, 2005).…”

Parietal lobe epilepsy: the great imitator among focal epilepsies

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non‐lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al , 2004).…”

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non-lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al, 2004). Synchronous or at least temporal overlapping activation of 10-20 cm 2 of gyral cortex is sufficient to produce scalp EEG spikes in the temporal lobe (Tao et al, 2005).…”

Seizure semiology in temporal lobe vs. temporal plus epilepsy using intracranial EEG monitoring

“…8 Furthermore, a similar conclusion can be drawn that even with focal anterior or infero-mesial epileptiform discharges, it does not exclude the possibility of extratemporal origin. 21 The most frequent inter-ictal patterns were ipsilateral temporal spikes and sharp waves, consistent with the literature. 8 Also, studies showed that TPE cases with bilateral inter-ictal abnormalities are associated with poor postoperative outcomes.…”

Temporal lobe epilepsy surgery failures: predictors of seizure recurrence, yield of reevaluation, and outcome following reoperation

“…10,24,30,33 An extratemporal or "temporal plus" epilepsy involving the insula has been proposed as an important reason for treatment failure in patients with early ictal signs and symptoms suggesting initial extratemporal involvement of the perisylvian region, the orbitofrontal cortex, or the temporoparietooccipital junction (as with our group without any automotor semiology after temporal lobe surgery), and in those with suspected TLE but normal MR imaging requiring SDEs (as in our cohort needing SDEs prior to tailored resections). 2,22,23 Our overall rate of seizure freedom with reoperation (6 [40%] of 15 cases) mirrors that of prior series of reoperation after failed TLE surgery 7,20,26,29 identifying short epilepsy duration, 29 a reoperation involving the initial surgical bed, 34 focal preoperative interictal discharges, 26,29 a history of febrile seizures or abnormal imaging, 26 and a tumoral etiology 7 as possible favorable prognostic indicators. Similarly, we found that MCD and MTS, as well as semiology suggesting an extratemporal focus, were associated with lower chances of success with reoperation on univariate analysis (Table 6).…”

Parietal lobe epilepsy: the great imitator among focal epilepsies

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non‐lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al , 2004).…”

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non-lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al, 2004). Synchronous or at least temporal overlapping activation of 10-20 cm 2 of gyral cortex is sufficient to produce scalp EEG spikes in the temporal lobe (Tao et al, 2005).…”

Seizure semiology in temporal lobe vs. temporal plus epilepsy using intracranial EEG monitoring

“…8 Furthermore, a similar conclusion can be drawn that even with focal anterior or infero-mesial epileptiform discharges, it does not exclude the possibility of extratemporal origin. 21 The most frequent inter-ictal patterns were ipsilateral temporal spikes and sharp waves, consistent with the literature. 8 Also, studies showed that TPE cases with bilateral inter-ictal abnormalities are associated with poor postoperative outcomes.…”

Temporal lobe epilepsy surgery failures: predictors of seizure recurrence, yield of reevaluation, and outcome following reoperation

“…10,24,30,33 An extratemporal or "temporal plus" epilepsy involving the insula has been proposed as an important reason for treatment failure in patients with early ictal signs and symptoms suggesting initial extratemporal involvement of the perisylvian region, the orbitofrontal cortex, or the temporoparietooccipital junction (as with our group without any automotor semiology after temporal lobe surgery), and in those with suspected TLE but normal MR imaging requiring SDEs (as in our cohort needing SDEs prior to tailored resections). 2,22,23 Our overall rate of seizure freedom with reoperation (6 [40%] of 15 cases) mirrors that of prior series of reoperation after failed TLE surgery 7,20,26,29 identifying short epilepsy duration, 29 a reoperation involving the initial surgical bed, 34 focal preoperative interictal discharges, 26,29 a history of febrile seizures or abnormal imaging, 26 and a tumoral etiology 7 as possible favorable prognostic indicators. Similarly, we found that MCD and MTS, as well as semiology suggesting an extratemporal focus, were associated with lower chances of success with reoperation on univariate analysis (Table 6).…”

Parietal lobe epilepsy: the great imitator among focal epilepsies

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non‐lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al , 2004).…”

“…These anatomical connections may account for the diffuse, interictal EEG distribution observed in PLE cases. Similarly to our results, exclusively temporal spikes or broad hemispheric spikes with temporal preponderance were described in non-lesional intractable epilepsy patients with parietal lobe symptomatology (Aghakhani et al, 2004). Synchronous or at least temporal overlapping activation of 10-20 cm 2 of gyral cortex is sufficient to produce scalp EEG spikes in the temporal lobe (Tao et al, 2005).…”

Seizure semiology in temporal lobe vs. temporal plus epilepsy using intracranial EEG monitoring

“…8 Furthermore, a similar conclusion can be drawn that even with focal anterior or infero-mesial epileptiform discharges, it does not exclude the possibility of extratemporal origin. 21 The most frequent inter-ictal patterns were ipsilateral temporal spikes and sharp waves, consistent with the literature. 8 Also, studies showed that TPE cases with bilateral inter-ictal abnormalities are associated with poor postoperative outcomes.…”

Temporal lobe epilepsy surgery failures: predictors of seizure recurrence, yield of reevaluation, and outcome following reoperation

“…10,24,30,33 An extratemporal or "temporal plus" epilepsy involving the insula has been proposed as an important reason for treatment failure in patients with early ictal signs and symptoms suggesting initial extratemporal involvement of the perisylvian region, the orbitofrontal cortex, or the temporoparietooccipital junction (as with our group without any automotor semiology after temporal lobe surgery), and in those with suspected TLE but normal MR imaging requiring SDEs (as in our cohort needing SDEs prior to tailored resections). 2,22,23 Our overall rate of seizure freedom with reoperation (6 [40%] of 15 cases) mirrors that of prior series of reoperation after failed TLE surgery 7,20,26,29 identifying short epilepsy duration, 29 a reoperation involving the initial surgical bed, 34 focal preoperative interictal discharges, 26,29 a history of febrile seizures or abnormal imaging, 26 and a tumoral etiology 7 as possible favorable prognostic indicators. Similarly, we found that MCD and MTS, as well as semiology suggesting an extratemporal focus, were associated with lower chances of success with reoperation on univariate analysis (Table 6).…”