Mesial temporal lobe epilepsy with amygdalar hamartoma-like lesion: Is it a distinct syndrome?

INTRODUCTION: We examined the clinical, semiological, scalp electroencephalographic (EEG), and neuropsychological features of patients with amygdalar hamartoma-like lesion (AHL) without hippocampal sclerosis (HS). METHODS: This retrospective study included 9 patients with mesial temporal lobe epilepsy (MTLE) who had an amygdalar lesion on preoperative MRI; underwent mesial temporal resection; were diagnosed with amygdalar hamartoma-like lesion (AHL) without hippocampal sclerosis (HS); were followed up for at least 2 years after surgery; and had a favourable postoperative seizure outcome (Engel Class I). There were 5 women and 4 men, and age at surgery ranged from 19 to 54 (mean, 36.6) years. Clinical characteristics, auras, video-recorded seizure semiology, interictal and ictal EEG, and preoperative neuropsychological data were reviewed. Twenty patients with MTLE with HS who had favourable postoperative seizure outcomes (Engel Class I) were selected as controls. RESULTS: Age at seizure onset was significantly higher in patients with AHL without HS than in those with HS. Fear was more frequently seen in patients with AHL (44 %) than in those with HS (5 %) (P = 0.022). There were no significant differences in interictal epileptiform discharges or ictal EEG pattern. Preoperative full-scale IQ score was significantly higher in the AHL group than in the HS group (mean, 92.9 v. 74.8, P = 0.004), as was preoperative memory quotient score (mean 100.7 v. 85.1, P = 0.028). CONCLUSION: We clarified the clinical, semiological, and neuropsychological features of patients with MTLE-AHL. These findings may be useful for preoperative evaluation, especially of patients with suspected MTLE but without apparent HS on preoperative MRI.

Neuropsychological outcomes after frontal lobectomy to treat intractable epilepsy.

OBJECTIVE: Frontal lobectomy is often used as a surgical treatment for frontal lobe epilepsy, especially when a large epileptogenic zone in the frontal lobe is inferred from preoperative evaluation. The frontal lobe is important for cognitive functions such as executive functions and verbal fluency, but the neuropsychological outcome after a frontal or prefrontal lobectomy that includes both the dorsolateral prefrontal cortex and ventral prefrontal cortex has not been studied thoroughly. In the present study, we evaluated neuropsychological outcomes after patients with frontal lobe epilepsy received a frontal or prefrontal lobectomy. METHODS: We retrospectively reviewed the data of patients with frontal lobe epilepsy who underwent a frontal or prefrontal lobectomy that includes both the dorsolateral prefrontal cortex and ventral prefrontal cortex at 16 years or older from October 2004 to December 2014, with a minimum postoperative follow-up of 24 months. We analyzed and compared neuropsychological outcomes, including executive functions, verbal fluency, intelligence, and memory, before and after the operation. RESULTS: Eighteen patients were 16 years or older and underwent pre- and postoperative (2 years after the operation) neuropsychological evaluations. Patients showed significant deterioration only on the Benton Visual Retention Test. Performance on tests of frontal lobe functions, such as executive function and verbal fluency, showed no significant deterioration. CONCLUSIONS: Overall cognitive performance, including functions widely thought to depend on the frontal lobe, is stable after a frontal or prefrontal lobectomy to treat frontal lobe epilepsy.

Semiological differences of focal onset bilateral motor (convulsive) seizure between mesial temporal lobe epilepsy and neocortical epilepsy.

OBJECTIVE: We investigated the semiology of focal onset bilateral motor (convulsive) seizure (FBMS) in patients with intractable focal epilepsy who underwent epilepsy surgery to understand its value in localizing the origin of the seizure. METHODS: The study included 20 patients who underwent resective surgery after intracranial video-EEG monitoring (iEEG) with a favorable seizure outcome (Engel class I), and had at least one FBMS during iEEG. The diagnosis was mesial temporal lobe epilepsy (MTLE) for 7 patients and neocortical epilepsy (NE) for 13 patients (lateral temporal lobe, 3; posterior cortex, 6; frontal lobe, 3; perirolandic, 1). Videotaped FBMSs were carefully analyzed. RESULTS: A generalized tonic phase appeared in all 7 patients with MTLE, but was absent in 6 of the 13 patients with NE (P = .044). Tonic cry was more frequently observed in MTLE than in NE (P = .012). Facial tonicity preceding limb tonicity was more frequently seen in patients with MTLE (P = .001). CONCLUSION: Notably, patients with MTLE and those with NE showed semiological differences during bilateralization. FBMS includes not only focal to bilateral tonic-clonic seizure but also focal to bilateral clonic seizure.

Surgical strategy for refractory epilepsy secondary to porencephaly: ictal SPECT may obviate the need for intracranial electroencephalography. Patient series.

BACKGROUND: Surgical treatment of intractable epilepsy caused by porencephaly can be difficult because of poorly localizing or lateralizing electroclinical findings. The authors aimed to determine whether noninvasive evaluations are sufficient in these patients. OBSERVATIONS: Eleven patients were included in this study. The porencephalic cyst was in the left middle cerebral artery (MCA) area in 9 patients, the left posterior cerebral artery area in 1 patient, and the bilateral MCA area in 1 patient. Interictal electroencephalography (EEG) revealed multiregional, bilateral, interictal epileptiform discharges in 5 of 11 patients. In 6 of 10 patients whose seizures were recorded, the ictal EEG was nonlateralizing. Nine patients underwent ictal single-photon emission computed tomography (SPECT), which revealed lateralized hyperperfusion in 8 of 9 cases. Fluorodeoxyglucose positron emission tomography (FDG-PET) was useful for identifying the functional deficit zone. No patient had intracranial EEG. The procedure performed was hemispherotomy in 7 patients, posterior quadrant disconnection in 3 patients, and occipital disconnection in 1 patient. A favorable seizure outcome was achieved in 10 of 11 patients without the onset of new neurological deficits. LESSONS: Ictal SPECT was useful for confirming the side of seizure origin when electroclinical findings were inconclusive. Thorough noninvasive evaluations, including FDG-PET and ictal SPECT, enabled curative surgery without intracranial EEG. Seizure and functional outcomes were favorable.

Retained absolute pitch after selective amygdalohippocampectomy.

This study assessed the pre-operative chronic condition and effect of epilepsy surgery in a 21-year-old Japanese woman with drug-resistant right temporal lobe epilepsy (TLE). For this patient, it was crucially important to preserve language and her music capabilities, including absolute pitch (AP), which is found in the general population at less than 0.1%. The patient became seizure free, and her AP capability was preserved after selective amygdalohippocampectomy in the non-dominant right hemisphere. Most of the neuropsychological test (WAIS-III and WMS-R) scores remained in the normal range, except for low scores in verbal memory and markedly improved attention/concentration index. The patient's pre- and postoperative brain function related to language and music capabilities were investigated using functional magnetic resonance imaging (fMRI) based on two language tasks and a music task (listening to melodies). While task performance was similar in pre- and postoperative examinations, her brain activation patterns markedly differed. The most striking difference was during the music task: areas with significant activation existed in the bilateral frontal and temporal lobes before surgery, whereas postoperative activation was confined to a very limited region in the left angular gyrus. The authors speculate that the surgery triggered some change in functional organization in the brain, which contributed to preserving her capabilities.

Semiology of hyperkinetic seizures of frontal versus temporal lobe origin.

Hyperkinetic seizures are usually associated with frontal lobe epilepsy. However, some patients have hyperkinetic seizures of temporal lobe origin. The semiological differences in hyperkinetic seizures between frontal and temporal lobe epilepsy have not been well studied. Here, we retrospectively assessed ictal semiology in order to distinguish between hyperkinetic seizures of frontal lobe origin and those of temporal lobe origin. We retrospectively reviewed data on patients who had undergone surgery for hyperkinetic seizures of temporal or frontal lobe origin and achieved favourable seizure outcomes (Engel Class I) with a minimum postoperative follow-up of 24 months. We reviewed seizure histories, imaging reports, video-EEG monitoring data, operative records, and pathological findings. We analysed and compared the hyperkinetic semiology of video-recorded seizures of temporal lobe origin and those of frontal lobe origin. Forty hyperkinetic seizures in eight patients (seven adult patients and one 12-year-old patient) with temporal lobe epilepsy and 45 hyperkinetic seizures in nine patients (eight adult patients and one 16-year-old patient) with frontal lobe epilepsy were analysed. Emotional facial expressions (such as fear, laughing, or anger), bilateral forceful elbow flexion, bilateral forceful grasping, facial flushing, and bilateral facial contraction were observed significantly more frequently in seizures of frontal lobe origin. Oroalimentary automatisms, seizures during wakefulness, salivation, and bilateral drop of the corners of the mouth were observed significantly more frequently in seizures of temporal lobe origin. Observation of a number of signs during hyperkinetic manifestations may help to predict whether a seizure originates from the frontal lobe or the temporal lobe.

Is additional mesial temporal resection necessary for intractable epilepsy with cavernous malformations in the temporal neocortex?

PURPOSE: Cavernous malformation (CM) in the temporal neocortex causes intractable epilepsy. Whether to resect additional mesial temporal structures in addition to the lesionectomy is a still controversial issue. To clarify the need for the procedure, we retrospectively analyzed pre- and postoperative clinical data of patients with surgically removed CM. SUBJECTS AND METHODS: We included data from 18 patients with CM in the temporal neocortex who presented with intractable epilepsy. Eleven patients of our early series were treated with extended resection, i.e., lesionectomy and the resection of additional mesial temporal structures. Seven patients underwent lesionectomy, i.e., removal of the CM and of hemosiderin-stained surrounding brain tissue. Pathological assessments of the resected hippocampus were performed. Chronic intracranial electroencephalography (EEG) recordings were obtained in 6 patients. We performed perioperative neuropsychological assessments in all patients. RESULTS: The seizure outcome was recorded as Engel class I in 17 patients (94.4%); Ia = 12 (66.7%) Ib = 2 (11.1%), Ic = 1 (5.6%), Id = 2 (11.1%), and class IIb in one patient (5.6%). Adding resection of the mesial temporal structures to lesionectomy did not alter the seizure outcome. Pathology of hippocampus revealed limited neuronal loss in CA4. Ictal onsets in the ipsilateral lateral cortex were detected in all 6 patients who underwent intracranial EEG. In 4 patients each, we also detected ictal onsets from the ipsilateral mesial temporal structures and from the contralateral temporal lobe. Postoperatively, in the patients where their CM was located in the language-dominant hemisphere (n = 10), the full-scale intelligence quotient (IQ) and the performance IQ increased (p < 0.05), whereas the verbal memory (WMS-R) deteriorated in two of 5 patients. CONCLUSION: Excellent seizure outcomes were obtained even the lesionectomy alone. To confirm appropriate surgical strategy for lateral temporal CM with intractable epilepsy, further studies in large sample size are needed.

Risk factors of cognitive impairment in pediatric epilepsy patients with focal cortical dysplasia.

OBJECTIVE: The purpose of this study was to identify the risk factors of cognitive impairment in pediatric epilepsy patients with focal cortical dysplasia (FCD). METHODS: 77 patients with histopathologically confirmed FCD were studied. The statistical relationship between cognition levels and clinical factors at presurgical evaluation was analyzed. Cognitive function was evaluated by development quotient or intelligence quotient (DQ-IQ). RESULTS: Ages at seizure onset were younger than 15 years (mean ±â€¯SD; 5.0 ±â€¯4.2 years). Mean disease duration was 14.5 ±â€¯8.5 years. Mean age at pre-surgical DQ-IQ evaluation was 34.8 ±â€¯10.7 years. Mean DQ-IQ was 60.5 ±â€¯20.5, and 41 of 77 (53.2%) patients had mental retardation (DQ-IQ < 70). Younger seizure onset and seizure clustering were significantly associated with lower DQ-IQ (p < 0.001). A multiple regression study identified higher seizure frequency pattern, a history of epileptic spasm and status epilepticus as aggravating factors of DQ-IQ decline (R2 = 0.63, p < 0.001). On the other hand, the risk was decreased in patients with habitual focal aware seizure and transient seizure-free periods up to 6 months in the course of epilepsy. FCD location (FCD site, extent of radiological lesion and laterality) and histopathology of FCD did not affect DQ-IQ. CONCLUSIONS: Our study suggests that seizure characteristics including higher seizure frequency pattern, a history of epileptic spasm, status epilepticus, seizure clustering and early onset of seizure are risk factors of cognitive impairment in FCD patients.

Working memory deficit in drug-resistant epilepsy with an amygdala lesion.

This study compared temporal lobe epilepsy (TLE) patients with amygdala lesion (AL) without hippocampal sclerosis (HS) (TLE-AL) with patients with TLE and HS without AL (TLE-HS). Both subtypes of TLE arose from the right hemisphere. The TLE-AL group exhibited a lower Working Memory Index (WMI) on the Wechsler Adult Intelligence Scale, third edition (WAIS-III), indicating that the amygdala in the right hemisphere is involved in memory-related function. [18F]fluorodeoxyglucose positron emission topography (FDG-PET) showed glucose hypometabolism limited to the right uncus for the TLE-AL group. The results suggest the importance of considering cognitive functions in the non-dominant hemisphere to prevent impairment after surgery.

Surgical Resection of Amygdala and Uncus.

The amygdala and uncus are located close to important neurovascular structures. We describe a safe technique for resection of amygdala and uncus. Under general anesthesia, the patient is positioned supine, with the head rotated approximately 20 degrees to the unoperated side and slightly extended. By using a trans-anterior T1 subpial approach, the inferior horn of the lateral ventricle is opened, and hippocampectomy is performed. We treat an imaginary plane formed by the inferior circular sulcus of the insula, the endorhinal sulcus, and the inferior choroidal point as the upper border of amygdalar resection. After confirming the position of the inferior choroidal point, the border between the temporal stem and uncus is exposed from anterior to posterior. This border is continuous with the endorhinal sulcus. By exposing the endorhinal sulcus, the anterior choroidal artery and optic tract can be visualized. The amygdala is disconnected through complete exposure of the endorhinal sulcus to the inferior choroidal point. After the lateral side of the uncus is disconnected, the amygdala and uncus are removed en bloc. Since April 2014, we have used the described procedure to remove amygdalar-uncal lesions in 15 patients. The lesion was completely removed in all cases without complications. Histological specimens were obtained in all cases. Our procedure enables safe and complete removal of amygdalar-uncal lesions. Imagining the plane formed by the inferior circular sulcus, inferior choroidal point, and endorhinal sulcus is essential for complete removal of the lesion and for preserving important structures.

A classification system for verifying the long-term efficacy of resective surgery for drug-resistant seizures.

OBJECTIVE: To verify the long-term efficacy of resective surgery, we created a classification system in which strictly defined patterns of postoperative seizure emergence are incorporated as basic components and the seizure states throughout the entire follow-up period are assessed comprehensively. METHODS: In our system, Class I has three subclasses (A-C); subclasses A and B are identical to Engel I-A and I-B, respectively. Subclass C comprises patients whose disabling seizures remit within the first 2 years postoperatively. Patients in Class II have only 1-3 days with disabling seizures throughout follow-up after the first 2 years. Patients in Class III have a maximum of 3 seizure days annually, and those in Class IV have ≥4 seizure days annually after the first 2 years. Classes II-IV each have 2 subclasses (A and B): subclass A, late recurrence (i.e., the first seizure occurs after 2 years postoperatively); and subclass B, early recurrence (i.e., first seizure within 2 years). In 646 patients who underwent resective surgery (temporal lobe resection, 74.6%) and were followed for at least 8 years (mean, 14.6 years), we analyzed three patterns of postoperative seizures: early remission, late recurrence, and occasional seizures. In addition, we investigated the differences between the long-term seizure outcomes of the cohort as determined according to our system and the Engel scale. RESULTS: Overall, 52.9% of the cohort experienced at least one disabling seizure postoperatively throughout the follow-up period; in 1/3 of these patients, the first seizure occurred after 2 years. In 73.8% of the 80 patients who manifested the running-down phenomenon, seizure remission occurred within the first 2 years. In addition, 36.7% of the 283 patients who had disabling seizures after 2 years experienced only 1-3 seizure days. Engel Class I-C included about 30% of the patients who had ≥4 seizure days after 2 years. The long-term seizure outcomes, determined according to our system, were: Class I, 56.2% (C, 9.1%) of the overall cohort; Class II, 16.1% (A, 11.0%); and Class III/IV, 27.7% (A, 6.6%). CONCLUSION: Our system clarifies the actual effect of resective surgery more precisely than the Engel scale and thus may be useful for comparing outcomes between different surgical procedures or for identifying potential risk factors predicting unfavorable outcome.

Characteristics of EEG Seizure-Onset Patterns Recorded From Subdural Electrodes Over MRI-Visible Frontal Focal Cortical Dysplasia Type IIb Lesions.

PURPOSE: Focal cortical dysplasia (FCD) is intrinsically epileptogenic, and an MRI-visible lesion typically constitutes the core part of the epileptogenic zone. We aimed to identify ictal EEG patterns that represent the epileptogenic zone by using subdural electrodes placed over the MRI-visible FCD lesion. METHODS: We selected seven patients with frontal lobe epilepsy caused by pathologically proven FCD type IIb who underwent preoperative intracranial EEG evaluation with subdural electrodes followed by resection surgery with seizure-free outcome. The characteristics of ictal EEG patterns, interictal/ictal high-frequency oscillations, and ictal direct current shifts from intracranial electrodes placed over the MRI-visible lesion were analyzed. RESULTS: Two seizure-onset patterns (low voltage fast activity and fast spike activity) were identified. Low voltage fast activity was seen in all patients with a lateral frontal lesion, and it was always preceded by preictal spikes. Fast spike activity occurred only in patients with a mesial frontal lesion. Interictal/ictal high-frequency oscillations and ictal direct current shifts were seen in all patients. CONCLUSIONS: The epileptogenic zone of frontal FCD type IIb may be characterized by EEG seizure-onset patterns consisting of low voltage fast activity and fast spike activity accompanied by ictal high-frequency oscillations and ictal direct current shifts. Further study is needed to determine whether other seizure-onset patterns exist in patients with FCD type IIb.

Long-term outcomes of epilepsy surgery in 85 pediatric patients followed up for over 10 years: a retrospective survey.

OBJECTIVE The aim of this study was to investigate the treatment outcomes and social engagement of patients who had undergone pediatric epilepsy surgery more than 10 years earlier. METHODS Between 1983 and 2005, 110 patients younger than 16 years underwent epilepsy surgery at the National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders. The authors sent a questionnaire to 103 patients who had undergone follow-up for more than 10 years after surgery; 85 patients (82.5%) responded. The survey contained 4 categories: seizure outcome, use of antiepileptic drugs, social participation, and general satisfaction with the surgical treatment (resection of the epileptic focus, including 4 hemispherectomies). The mean patient age at the time of surgery was 9.8 ± 4.2 (SD) years, and the mean duration of postoperative follow-up was 15.4 ± 5.0 years. Of the 85 patients, 79 (92.9%) presented with a lesional pathology, such as medial temporal sclerosis, developmental/neoplastic lesions, focal cortical dysplasia, and gliosis in a single lobe. RESULTS For 65 of the 85 responders (76.5%), the outcome was recorded as Engel Class I (including 15 [93.8%] of 16 patients with medial temporal sclerosis, 20 [80.0%] of 25 with developmental/neoplastic lesions, and 27 [73.0%] of 37 with focal cortical dysplasia). Of these, 29 (44.6%) were not taking antiepileptic drugs at the time of our survey, 29 (44.6%) held full-time jobs, and 33 of 59 patients (55.9%) eligible to drive had a driver's license. Among 73 patients who reported their degree of satisfaction, 58 (79.5%) were very satisfied with the treatment outcome. CONCLUSIONS The seizure outcome in patients who underwent resective surgery in childhood and underwent followup for more than 10 years was good. Of 85 respondents, 65 (76.5%) were classified in Engel Class I. The degree of social engagement was relatively high, and the satisfaction level with the treatment outcome was also high. From the perspective of seizure control and social adaptation, resective surgery yielded longitudinal benefits in children with intractable epilepsy, especially those with a lesional pathology in a single lobe.

Seizures with tonic posturing: Semiologic difference between supplementary sensorimotor area (SSMA) origin and extra-SSMA origin.

In seizures with tonic posturing, differentiation of seizures originating in SSMA from seizures originating in cortices other than SSMA and spreading to SSMA has not been previously attempted. Twenty-two patients were studied with intractable focal epilepsy with tonic limb posturing as the most prominent semiology, who underwent resective surgery and obtained favorable postoperative seizure outcomes. These 22 patients were divided into an SSMA group (N = 12) and an extra-SSMA group (N = 10), according to the location of resection. Resection area in the extra-SSMA group was located in the dorsolateral frontal or prefrontal area in four patients, the frontal operculum (insula) in two, the parietal cortex in three, and the temporoparietal cortex in one patient. Video-recorded seizures were carefully reviewed. Tonic posturing characteristics and the presence or absence of accompanying symptoms were compared between groups. Incidence of preservation of consciousness was significantly higher in the SSMA group (p < 0.001). Patients in the SSMA group demonstrated a propensity for having unilateral or bilateral asymmetrical tonic limb posturing. In contrast, patients in the extra-SSMA group had a statistically significantly higher incidence of bilateral symmetrical tonic limb posturing (p < 0.05). These findings may be helpful in identifying seizure origin.

Significance of Very-High-Frequency Oscillations (Over 1,000Hz) in Epilepsy.

OBJECTIVE: We previously reported ictal very-high-frequency oscillations (VHFO) of 1,000 to 2,500Hz recorded by subdural macroelectrodes using a 10-kHz sampling rate. The purpose of this study was to clarify the clinical significance of ictal VHFO in neocortical epilepsy. METHODS: This study included 13 patients with neocortical epilepsy who underwent subdural electrode implantation and had at least 1 seizure recorded at a 10-kHz sampling rate and were followed for more than 2 years postoperatively. Extent of resection was determined considering the seizure onset zone (SOZ) and irritative zone, structural lesion, and functional areas. Areas showing VHFO and those with HFO were not taken into consideration. The presence or absence of VHFO (>1,000 Hz), HFO (200-1,000Hz) and SOZ, and completeness of resection of these areas were compared with postoperative seizure outcome. RESULTS: Seven patients had favorable (Engel class Ia) and 6 had unfavorable outcomes (other classes). VHFO was recorded in 6 of 7 patients with a favorable outcome. On the contrary, VHFO was recorded in only 1 of 6 patients with unfavorable outcome. The presence of VHFO was significantly associated with favorable outcome. VHFO was recorded on a limited number of electrodes, and VHFO-generating areas were resected completely, whereas HFO-generating areas and/or SOZ were not always resected completely in both favorable and unfavorable outcome groups. INTERPRETATION: The presence of ictal VHFO may be predictive of favorable outcome. Ictal VHFO may be a more specific marker than ictal HFO or SOZ for identifying the core of epileptogenic zone.

Semiological and electroencephalographic features of epilepsy with amygdalar lesion.

OBJECTIVE: To identify semiological and scalp/sphenoidal electroencephalographic (EEG) features of epilepsy with amygdalar lesion (AL). METHODS: This study included 17 patients with epilepsy and distinct AL on MRI, who underwent resective surgery. There were nine female and eight male patients with ages at surgery ranging from 8 to 48 (mean 26.3) years. Postoperative seizure outcome was Engel class I or seizure-free in 12 patients, class II in four, and class III in one. Pathological examination revealed dysembryoplastic neuroepithelial tumor in eight cases, astrocytoma in two, mixed oligoastrocytoma in three, ganglioglioma in two, localized encephalitis in one, and cortical dysplasia in one. Semiology and scalp/sphenoidal EEG findings of these patients (AL group) were compared with those of 20 mesial temporal lobe epilepsy patients with hippocampal sclerosis (HS) who underwent resective surgery with favorable seizure outcome (Engel class I) (control group). RESULTS: Increased tonic components during seizure were more frequently seen in AL group (58.8%) than in control group (20%). Interictal unitemporal slow waves were more frequently found in AL group (58.8%) than in control group (20%). Ictal EEG revealed generalized (not only bitemporal) onset in six patients in AL group (35.3%), but none in control group. The generalized EEG onset patterns in AL group included spike and wave complexes, rhythmic spikes, and delta waves. CONCLUSION: Patients with AL had increased tonic components during seizure and generalized ictal EEG onset more frequently than patients with HS. These findings suggest widespread epileptic network involving subcortical structures such as the thalamus and the brainstem in patients with AL.

Bidirectional neural connectivity between basal temporal and posterior language areas in humans.

OBJECTIVE: The basal temporal language area (BTL) is known to be involved in the semantic processing of language. To investigate the neural connectivity between BTL and the posterior language area (PL), we used cortico-cortical evoked potential (CCEP) technique. METHODS: Four patients with intractable epilepsy who underwent presurgical evaluation with subdural electrodes were examined. All patients were right-handed and left language dominance by Wada test. We directly stimulated 20 pairs of electrodes placed on BTL in patient 1-3, putative BTL in patient 4, and PL in patient 1-4. In patient 4, all electrodes on the left temporal basal area were stimulated. RESULTS: We could record 132 CCEP responses including 40 responses by the left basal temporal stimulation in patient 4. The waveforms from PL to BTL were triphasic, while those from BTL to PL were biphasic. The mean latency of the first negative peak (N1) was shorter at BTL (31.8-41.0ms; mean 35.1ms) than at PL (39.6-73.2ms; mean 52.3ms). CONCLUSIONS: We revealed the uneven bidirectional connection between BTL and PL. SIGNIFICANCE: We speculated that the two language areas are connected mainly through subcortical fibers from PL to BTL and through cortico-cortical fibers from BTL to PL, mediated by multisynaptic transmissions.

Preservation of absolute pitch after right amygdalohippocampectomy for a pianist with TLE.

Absolute pitch (AP) ability is a rare musical phenomenon. In the literature, it has been suggested that the relative specialization for pitch processing is in the right temporal lobe in the non-AP population. Since the anatomic basis for absolute pitch is not fully understood and cases of temporal lobe epilepsy of AP possessors are extremely rare, applicability of resection as a treatment of epilepsy in this particular area should be evaluated with caution. In the present study, we examined an AP possessor who suffered from medically refractory temporal lobe epilepsy and underwent right selective amygdalohippocampectomy (SAH). The SAH procedure clearly avoided disturbing important structures for AP, inasmuch as postsurgically she preserved her AP ability and was seizure-free. She did well post-operatively in the test of pure sine wave tones with short reaction time, which could be identified as "true" absolute pitch.

Developmental outcome after surgery in focal cortical dysplasia patients with early-onset epilepsy.

The purpose of this study was to investigate the developmental outcome after surgery for early-onset epilepsy in patients with focal cortical dysplasia (FCD). Among 108 patients with histopathologically confirmed FCD operated between 1985 and 2008, we selected 17 patients with epilepsy onset up to 3 years of age. Development was evaluated by the developmental quotient or intelligence quotient (DQ-IQ) and mental age was measured by the Mother-Child Counseling baby test or the Tanaka-Binet scale of intelligence. Postsurgical development outcome was evaluated by the changes in DQ-IQ and mental age as well as rate of increase in mental age (RIMA) after surgery. RIMA was calculated as the increase in mental age per chronological year (months/year; normal average rate: 12 months/year). Age at epilepsy onset of 17 patients ranged from 15 days to 36 months (mean±SD, 11.0±10.0 months). Age at surgery ranged from 18 to 145 months (75.1±32.4 months). Evaluation just before surgery showed that 13 of 17 (76.4%) patients had DQ-IQ below 70. Ten patients (58.8%) were seizure-free throughout the postsurgical follow-up period. After surgery, DQ-IQ was maintained within 10 points of the presurgical level in 13 patients (76.4%), and increased by more than 10 points in one patient (5.9%). After surgery, RIMA in patients with Engel's class I (7.5±3.8) was higher than patients with Engel's class II-IV (2.6±3.4) (unpaired t-test with Welch's correction, t=2.99, df=15, p=0.0092). RIMA was particularly low in two patients with spasm. In four patients with presurgical DQ-IQ<70, seizure-free after surgery and without spasm, DQ-IQ did not increase but RIMA improved from 3.6±2.8 before surgery to 6.9±2.5 months/year after surgery. RIMA became better from 2 years after surgery. In four patients with presurgical DQ-IQ≥70 and no spasm, two showed the same or higher RIMA than normal average after surgery. In 58.8% of FCD patients with early onset epilepsy, epilepsy surgery effectively controlled seizures, and in 82.3% of patients, epilepsy surgery preserved or improved development. Residual seizures after surgery and lower DQ-IQ before surgery might be potential risk factors for poor development after surgery. In patients of Engel's class I with lower presurgical DQ-IQ, catch-up increase in mental age was observed after two years following surgery.

Mesial temporal lobe epilepsy with no specific histological abnormality: a distinct surgically remediable syndrome.

PURPOSE: The purposes of the study were twofold: to clarify the clinical features and surgical outcome of mesial temporal lobe epilepsy (MTLE) with no specific histological abnormality and to determine the optimal surgical strategy. METHODS: Twelve patients who met the following criteria were included: (1) normal preoperative MRI; (2) intracranial EEG findings consistent with mesial temporal onset of seizures; (3) selective amygdalohippocampectomy (AHE) was performed, and the patient was followed for more than 2years postoperatively; and (4) hippocampal histopathology was nonspecific. Clinical characteristics, intracranial EEG findings, and postoperative seizure outcome were examined. These twelve patients were compared with twenty-one patients with MTLE with unilateral hippocampal sclerosis (HS) on MRI who underwent intracranial EEG before resection (control group). RESULTS: In patients with MTLE with no specific histological abnormality, the age at onset was significantly higher, the history of febrile seizures was significantly less frequent, and preoperative IQ score was significantly higher than that in the control group. The proportion of patients with bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG was 50% in patients with MTLE with nonspecific histopathology and was significantly higher than that in the control group. Seizure outcome was classified as Engel class I in seven patients, class II in three, class III in one, and class IV in one. Seizure outcome was favorable even in three patients with seizures originating more frequently from the side contralateral to the resected side. CONCLUSIONS: Mesial temporal lobe epilepsy with no specific histological abnormality is a clinical entity distinctly different from MTLE with HS. Bitemporal independent and/or nonlateralizing seizure onset on intracranial EEG is very common. Although the presence of lateral temporal and/or extratemporal epileptogenicity should always be kept in mind, postoperative seizure outcome after AHE is favorable even in cases with bitemporal independent and/or nonlateralizing seizure onset.