Propagation of seizures in a case of lesional mid‐cingulate gyrus epilepsy studied by stereo‐EEG

Little is known about the propagation of seizures arising from the cingulate gyrus, as cingulate coverage with interhemispheric subdural electrodes is usually challenging and incomplete due to inherent anatomical and vascular limitations. We present a case of lesional mid‐cingulate epilepsy confirmed by stereotactically implanted intracranial depth electrodes and subsequent surgical resection. Hypermotor symptomatology was seen during the first seven seconds of seizure onset while the seizure was still confined to the mid‐cingulate gyrus contacts. The patient had brief contralateral clonic movements as seizure propagated to the primary motor cortex. There was a high concordance between the primary propagation contacts, as delineated by intracranial EEG, and the contacts, with higher coherence values in the connectivity matrix. Interestingly, cingulate‐extra‐cingulate connectivity and spread to the primary motor, premotor, and prefrontal cortex was seen preceding spread to other cingulate contacts, of which one was less than 15 mm from the onset contact. This report is one of a few published, documenting propagation of seizures arising from the mid‐cingulate cortex. As illustrated by these data, hypermotor semiology correlated with direct activation of the cingulate cortex. Subsequent seizure propagation activated an extensive extra‐cingulate rather than an intra‐cingulate epileptogenic network. Interestingly, had the region of onset not sampled, the seizure onset would have appeared as non‐localizing widespread rhythms over the fronto‐parietal convexities. Further studies to explore the propagation of seizures arising from the cingulate gyrus and the physiological and pathological connectivity patterns within the cingulate gyrus in humans are needed, preferably using stereotactic implantation. Specific targets to be investigated are also discussed.     

Successful epilepsy surgery in frontal lobe epilepsy with startle seizures: a SEEG studyFrontal epilepsy with startle seizures

Pre‐surgical assessment and surgical management of frontal epilepsy with normal MRI is often challenging. We present a case of a 33‐year‐old, right‐handed, educated male. During childhood, his seizures presented with mandibular myoclonus and no particular trigger. As a young adult, he developed seizures with a startle component, triggered by unexpected noises. During his ictal episodes, he felt fear and grimaced with sudden head flexion and tonic axial posturing. Similar seizures also occurred without startle. Neuropsychological assessment showed executive dysfunction and verbal memory deficit. The cerebral MRI was normal. Electro‐clinical reasoning, investigations performed, the results obtained and follow‐up are discussed in detail. [Published with video sequence]     

Frequency‐specific changes in the default mode network in patients with cingulate gyrus epilepsy

To identify abnormal functional connectivity of the default mode network in cingulate gyrus epilepsy, which may yield new information about the default mode network and suggest a new cingulate gyrus epilepsy biomarker. Fifteen patients with cingulate gyrus epilepsy (mean age = 21 years) and 15 healthy controls (mean age = 24 years) were studied in the resting state using magnetoencephalography. Twelve brain areas of interest in the default mode network were extracted and investigated with multifrequency signals that included alpha (α, 8–13 Hz), beta (β, 14–30 Hz), and gamma (γ, 31–80 Hz) band oscillations. Patients with cingulate gyrus epilepsy had significantly greater connectivity in all three frequency bands (α, β, γ). A frequency‐specific elevation of functional connectivity was found in patients compared to controls. The greater functional connectivity in the γ band was significantly more prominent than that of the α and β bands. Patients with cingulate gyrus epilepsy and controls differed significantly in functional connectivity between the left angular gyrus and left posterior cingulate cortex in the α, β, and γ bands. The results of the node degree analysis were similar to those of the functional connectivity analysis. Our findings reveal for the first time that brain activity in the γ band may play a key role in the default mode network in cingulate gyrus epilepsy. Altered functional connectivity of the left angular gyrus and left posterior cingulate cortex may be a new biomarker for cingulate gyrus epilepsy.     

SEEG re‐exploration in a patient with complex frontal epilepsy with rapid perisylvian propagation and mixed “startle ‐ reflex” seizures

The SEEG International Course, organised in 2017, focused on the investigation and surgery of insulo‐perisylvian epilepsies. We present one representative complex case that was discussed. The patient had seizures displaying startle/reflex components. He was MRI negative, while other non‐invasive investigations offered only partially concordant data. Initial SEEG exploration resulted in an incomplete definition of the epileptogenic zone. A second SEEG followed, which led to a thorough assessment of the seizure onset zone and the epileptic network, localised to the lateral inferior premotor cortex, explaining the incongruent data obtained beforehand. This was the basis of a tailored resection with a favourable outcome. The patient has been seizure‐free for five years without any motor nor cognitive deficits, but with pharmacodependence to one AED. The electroclinical reasoning is presented, accompanied by relevant commentaries and recommendations from the tutors [Published with video sequences].     

Minimally resective epilepsy surgery in MRI‐negative children

Aim. Performing epilepsy surgery on children with non‐lesional brain MRI often results in large lobar or multilobar resections. The aim of this study was to determine if smaller resections result in a comparable rate of seizure freedom. Methods. We reviewed 25 children who had undergone focal corticectomies restricted to one aspect of a single lobe or the insula at our institution within a 5.5‐year period. Data collected in the comprehensive non‐invasive pre‐surgical evaluation (including scalp video‐EEG, volumetric MRI, functional MRI, EEG source localization, and SPECT and PET), as well as from invasive recordings performed in each patient, was reviewed. Data from each functional modality was identified as convergent or divergent with the epileptogenic zone using image coregistration. Specific biomarkers (from extra‐operative and invasive testing) previously indicated to be indicative of focal epileptogenicity were used to further tailor each resection to an epileptogenic epicentre. Tissue pathology and postoperative outcomes were obtained from all 25 patients. Results. Two years postoperatively, 15/25 (60%) children were seizure‐free, three (12%) experienced >90% reduction in seizure frequency, two (8%) had a 50–90% reduction in seizure frequency, and the remaining five (20%) had no change in seizure burden. There was no significant difference in outcome based on numerous pre‐ and postoperative factors including location of resection, the number of preoperative functional tests providing convergent data, and tissue pathology. Conclusion. In MRI‐negative children with focal epilepsy, an epileptogenic epicentre within a larger epileptogenic zone can be identified when specific biomarkers are recognized on non‐invasive and invasive testing. When such children undergo resection of a small, well‐defined epileptogenic epicentre, favourable outcomes can be achieved.     

Successful stereoelectroencephalography re-evaluation in epilepsy patients after failed initial subdural grid evaluation

Objective

Epilepsy surgery success is dependent on accurate localization of the epileptogenic zone. Despite the use of invasive EEG using subdural grids and strips, surgical failures can occur. In this series, we explore the utility of a second evaluation with stereoelectroencephalography in patients whose initial invasive evaluation with subdural grid electrodes was unsuccessful in localizing seizure origin.

Methods

We conducted a retrospective review of patients who underwent subdural grid evaluation (SDE) at our center and identified patients who underwent a re-evaluation with stereoelectroencephalography (SEEG).

Results

We identified three patients who had both subdural and SEEG electrodes in the region of the identified epileptogenic zone in whom the initial SDE evaluation failed to make the patients seizure-free. Two of these patients underwent a second resection and became seizure-free.

Significance

Stereoelectroencephalography can be useful in the re-evaluation and re-operation of patients who previously had surgical failure using SDE.     

Double Inversion Recovery Magnetic Resonance Imaging in Identifying Focal Cortical Dysplasia

BackgroundFocal cortical dysplasia is commonly recognized in pediatric epilepsy surgery. Despite characteristic radiographic features, focal cortical dysplasia can be subtle on magnetic resonance imaging. Double inversion recovery acquisition suppresses the white matter signal, which may enhance visualization of abnormal features at the gray–white matter interface. We assessed the ability of double inversion recovery to distinguish focal cortical dysplasia from periventricular nodular heterotopia and normal brain.MethodsPatients with focal cortical dysplasia were identified from our patient database, as was a control group comprising patients with periventricular nodular heterotopia and healthy persons. A senior neuroradiologist reviewed all clinical images and classified them as patients with focal cortical dysplasia (n = 16) or control subjects (periventricular nodular heterotopia, n = 13; normal, n = 20). Four neuroradiologists reviewed the de-identified and randomized double inversion recovery and magnetization prepared rapid acquired gradient echoes (MPRAGE) sequences for each person and scored them as normal, focal cortical dysplasia, or periventricular nodular heterotopia.ResultsAmong individual reviewers, double inversion recovery showed sensitivity from 50% to 88% and specificity from 67% to 91% in detecting focal cortical dysplasia. The sensitivity was notably higher in reviewers with more clinical experience with the technique. Consensus agreement among the three most experienced reviewers gave a sensitivity of 88% (95% confidence interval [CI], 72% to 97%) and specificity of 88% (95% CI, 62% to 98%) for double inversion recovery and sensitivity of 44% (95% CI, 20% to 70%) and specificity of 100% (95% CI, 89% to 100%) for MPRAGE.ConclusionsDouble inversion recovery is sensitive for detection of focal cortical dysplasia with experienced users, particularly when there is consensus agreement. The use of two clinically available magnetic resonance imaging acquisitions—double inversion recovery and another sequence with high specificity such as MPRAGE—would be complementary in the evaluation of lesional epilepsy.     

Associational connections between the anterior and postetior cingulate gyrus in rabbit

Reciprocal anatomical connections between anterior and posterior divisions of the cingulate gyrus are described for the rabbit. Cells within the anterior limbic and precentral agranular regions of the rostral cingulate gyrus, predominantly from layer V, send afferebts to layer I of posterior cingulate and retrosplenial cortices. Cells from layers II and III of posterior cingulate and from layer V of retrosplenial cortex project rostrally to the anterior limbic and precentral agranular cortices. These data demonstrate the existence of an associational anatomical system connecting anterior and posterior regions of the cingulate gyrus.     

Surgical outcome and predictive factors in adult patients with intractable epilepsy and focal cortical dysplasia

OBJECTIVES: To determine the surgical outcome and prognostic factors in adult patients with intractable epilepsy and focal cortical dysplasia (FCD). MATERIALS AND METHODS: We retrospectively studied the operative outcome in 21 consecutive adult patients with FCD who underwent surgical treatment for intractable partial epilepsy. RESULTS: The mean age at surgery was 32.7 years (range, 18-58 years). The median post-operative follow-up was 2.5 years. The FCD was extratemporal in 11 patients, involved the temporal lobe in 10 patients, and was multilobar in eight patients. Eleven patients (52%) were rendered seizure-free, four patients (19%) had >95% reduction in seizures, and two patients (10%) had an 80-94% reduction in seizures. A seizure-free outcome was associated with shorter duration of epilepsy (P = 0.02). CONCLUSION: Adult patients with FCD may be candidates for surgical treatment of intractable partial epilepsy. Most individuals have neocortical, extrahippocampal seizures and approximately 50% of patients are rendered seizure-free.     

局灶性皮质发育不良所致难治性癫痫的微创神经外科治疗

目的应用神经导航结合术中皮质电极描记,微创治疗局灶性皮质发育不良(focal cortical dysplasia,FCD)所致的难治性癫痫。方法 26例局灶性皮质发育不良所致的难治性癫痫患者,术前常规使用CT、磁共振成像(magnetic resonanceimaging,MRI)、长程视频脑电图(digital video signal and electroencephalogram,VEEG)、磁共振波谱分析(MR Spectroscopy,MRS)等检查,如病灶位于功能区则行功能性磁共振成像(functional magnetic resonance imaging,fMRI)。术中通过神经导航确定的病灶与ECoG确定的致痫灶位置及范围进行对比,了解两者的吻合程度及差异,综合分析后精确并标记出癫痫波的起源位置和范围,将局灶性皮质发育不良病灶和周边的致痫皮质切除;如致痫灶位于功能区或附近,在保留功能区皮质的基础上,给予低功率皮质热灼。结果术后病理结果:26例患者病理标本符合FCD。术后患者无明显并发症出现。根据Engel术后效果分级进行评估,Ⅰ级23例,Ⅱ级2例,Ⅲ级1例。结论神经导航结合术中皮质电极描记在局灶性皮质发育不良所致的难治性癫痫手术中,具有定位准确、损伤少的优点,在切除致痫灶的同时能最大程度保护脑功能。     

Resting state functional connectivity of the anterior cingulate cortex in veterans with and without post‐traumatic stress disorder

Post‐traumatic stress disorder (PTSD) is an anxiety disorder that is associated with structural and functional alterations in several brain areas, including the anterior cingulate cortex (ACC). Here, we examine resting state functional connectivity of ACC subdivisions in PTSD, using a seed‐based approach. Resting state magnetic resonance images were obtained from male veterans with (n = 31) and without (n = 25) PTSD, and healthy male civilian controls (n = 25). Veterans with and without PTSD (combat controls) had reduced functional connectivity compared to healthy controls between the caudal ACC and the precentral gyrus, and between the perigenual ACC and the superior medial gyrus and middle temporal gyrus. Combat controls had increased connectivity between the rostral ACC and precentral/middle frontal gyrus compared to PTSD patients and healthy civilian controls. The resting state functional connectivity differences in the perigenual ACC network reported here indicate that veterans differ from healthy controls, potentially due to military training, deployment, and/or trauma exposure. In addition, specific alterations in the combat controls may potentially be related to resilience. These results underline the importance of distinguishing trauma‐exposed (combat) controls from healthy civilian controls when studying PTSD. Hum Brain Mapp, 36:99–109, 2015. © 2014 Wiley Periodicals, Inc.     

Characterizing anterior cingulate activation in chronic schizophrenia: a group and single-subject fMRI study

OBJECTIVE: Functional abnormalities of the dorsal anterior cingulate (dAC) region have been emphasized in schizophrenia, particularly in relation to cognitive deficits. In this study, we sought to further evaluate the notion of dAC hypofunction in chronic schizophrenia patients using a cognitive task specifically designed to activate this region, enabling both group and single-subject level analyses. METHOD: Twelve male schizophrenia patients and 14 male healthy subjects were studied with functional magnetic resonance imaging (fMRI) and the multi-source interference task (MSIT). Patients and healthy subjects were matched for age, gender, education, task performance and gross surface morphology of the AC region. fMRI analyses were conducted at the group and single-subject levels using stringent whole-brain activation thresholds. RESULTS: Multi-source interference task performance was associated with large and significant activation of the dAC and supplementary motor area (SMA) in patients and healthy subjects. Standard comparison of the two groups indicated that the patients were comparable with healthy subjects in their dAC activation, but had a small cluster of greater SMA activation, while single-subject analyses identified minimal differences in the magnitude or spatial dispersion of dAC activation between the groups. CONCLUSION: These findings challenge existing notions of impaired dAC activation in chronic schizophrenia and suggest that the functional pathophysiology of this medial-wall region should be considered beyond straightforward models of hypoactivation.     

Volumetric magnetic resonance imaging study of the anterior cingulate gyrus in schizotypal disorder

Lack of normal structural asymmetry of the anterior cingulate gyrus (ACG) in patients with schizophrenia has been reported in our previous study. However, to our knowledge, no morphological studies of the brain have examined changes in ACG volume in patients with schizotypal features. We investigated the volume of the gray matter and the white matter of the ACG by three-dimensional magnetic resonance imaging (MRI) in 24 patients who met the ICD-10 criteria for schizotypal disorder (12 males, 12 females) in comparison with 48 age- and gender-matched healthy control subjects (24 males, 24 females) and 40 patients with schizophrenia (20 males, 20 females). As we reported previously, right ACG gray matter volume was significantly reduced in the female patients with schizophrenia compared with the female controls. On the other hand, the gray and white matter volume of the ACG in the patients with schizotypal disorder did not differ significantly from the values in the healthy controls or the patients with schizophrenia. However, the female patients with schizotypal disorder showed a lack of right-greater-than-left asymmetry of the ACG gray and white matter found in the female controls. These results suggest that both schizotypal and schizophrenic subjects share, at least in part, the same cerebral asymmetry abnormalities. Received: 28 May 2002 / Accepted: 30 October 2002 Correspondence to T. Takahashi