Distributed source modeling of stereoencephalographic measurements of ictal activity

OBJECTIVES

Stereoelectroencephalography (SEEG) can define the epileptogenic zone (EZ). However, SEEG is susceptible to the sampling bias, where no SEEG recording is taken within a circumscribed EZ.

METHODS

Nine patients with medically refractory epilepsy underwent SEEG recording, and brain resection got positive outcomes. Ictal neuronal currents were estimated by distributed source modeling using the SEEG data and individual's anatomical magnetic resonance imaging. Using a retrospective leave-one-out data sub-sampling, we evaluated the sensitivity and specificity of the current estimates using MRI after surgical resection or radio-frequency ablation.

RESULTS

The sensitivity and specificity in detecting the EZ were indistinguishable from either the data from all electrodes or the sub-sampled data (rank sum test: rank sum = 23719, p = 0.13) when at least one remaining electrode contact was no more than 20 mm away.

CONCLUSIONS

The distributed neuronal current estimates of ictal SEEG data can mitigate the challenge of delineating the boundary of the EZ in cases of missing an electrode implanted within the EZ and a required second SEEG exploration.

SIGNIFICANCE

Distributed source modeling can be a tool for clinicians to infer the EZ by allowing for more flexible planning of the electrode implantation route and minimizing the number of electrodes.

Glucose Metabolism of Hippocampal Subfields in Medial Temporal Lobe Epilepsy

PURPOSE

Reduced glucose metabolism in the hippocampus is commonly observed in cases of medial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (HS). Glucose metabolism among the various hippocampal subfields has not been thoroughly investigated.

PATIENTS AND METHODS

This study examined 29 patients (18 females; 15-58 years) diagnosed with HS who underwent surgery for drug-resistant epilepsy. FreeSurfer 7.1.1 was used in the processing of MRI data and 18 F-FDG PET scans to derive volumetric data and the FDG SUVr in the whole hippocampus and hippocampal subfields, including the CA1, CA2-4, granule cell and molecular layer of the dentate gyrus (GC-ML-DG), and subiculum. Asymmetries in the volume and SUVr between the 2 sides from the subfields of the hippocampus were defined in terms of an asymmetry index. Comparisons of the asymmetry index among these regions were performed. The correlations between asymmetry index values and postoperative outcomes and presurgical neuropsychological test results were also evaluated.

RESULT

The CA1, CA2-4, subiculum, GC-ML-DG, and whole hippocampus presented reductions in volume and hypometabolism ipsilateral to MTLE. Asymmetries in volume and SUVr were significantly less pronounced in the CA1 and subiculum than in the CA2-4 or GC-ML-DG. Postoperative seizure outcomes were not correlated with the asymmetry index for volume or SUVr in any hippocampal subfield. In cases of left MTLE, scores of immediate logical memory and delayed logical memory were positively correlated with the asymmetry index for SUVr in the following subfields: CA1 ( R = 0.829, P = 0.021; R = 0.770, P = 0.043), CA2-4 ( R = 0.825, P = 0.022; R = 0.894, P = 0.007), subiculum ( R = 0.882, P = 0.009; R = 0.853, P = 0.015), GC-ML-DG ( R = 0.850, P = 0.015; R = 0.796, P = 0.032), and whole hippocampus ( R = 0.841, P = 0.018; R = 0.822, P = 0.023). In cases of right MTLE, the scores for delayed face memory were positively correlated with the asymmetry index for SUVr in the subiculum ( R = 0.935, P = 0.006).

CONCLUSIONS

In cases of HS, changes in glucose metabolism levels varied among the hippocampal subfields. Asymmetries in glucose metabolism among the CA-1, CA2-4, subiculum, and GC-ML-DG subregions were correlated with scores for verbal memory among patients with left MTLE. Asymmetric glucose metabolism in the subiculum was also correlated with visual memory scores among patients with right MTLE.

Development and construction of the Multidimensional Self-Efficacy Scale for Epilepsy (MSESE) and its psychometric properties

PURPOSE

It has become evident that patients with epilepsy require strong self-efficacy support in various domains, including work, social interaction, and academic performance, to ensure their complete social functioning. Nevertheless, previous studies have predominantly assessed the self-efficacy of individuals with epilepsy from a singular perspective of disease management. This study aimed to develop the Multidimensional Self-Efficacy Scale for Epilepsy (MSESE) to assess multiple dimensions and establish its psychometric properties.

METHODS

We compiled a total of 25 questions for the initial version of the questionnaire based on a review of the literature and insights from experts, patients, and family members. The study included 180 adult patients with epilepsy who met the research criteria, with 126 of them serving as pre-test samples. All participants completed the MSESE, Brief Symptom Rating Scale-50 (BSRS-50), Rosenberg Self-Esteem Scale-Chinese version (RSES-C), and General Self-Efficacy Scale (GSES).

RESULTS

The final scale consisted of 12 items across four dimensions, with item factor loadings ranging from .51 to .90. Most of the fit indices indicated a good fit. Construct validity was established through significant correlations with the BSRS-50, RSES-C, and GSES (r = -0.51 to 0.69, p < 0.01). Internal consistency coefficients for the MSESE were strong at .90, with individual dimensions ranging from 0.71 to 0.89. The MSESE also demonstrated a satisfactory test-retest reliability of 0.72.

CONCLUSIONS

The MSESE is a convenient, multidimensional, and easy-to-use scale with good psychometric properties, making it suitable for both clinical assessments and research purposes.

Frame-based versus robot-assisted stereo-electro-encephalography for drug-resistant epilepsy

BACKGROUND

Stereoelectroencephalography (SEEG) is an effective presurgical invasive evaluation for drug-resistant epilepsies. The introduction of robotic devices provides a simplified, accurate, and safe alternative to the conventional SEEG technique. We report our institutional experience with robot-assisted SEEG and compare its in vivo accuracy, operation efficiency, and safety with the more traditional SEEG workflow.

METHODS

All patients with medically refractory focal epilepsy who underwent SEEG depth electrode implantation between 2014 and 2022 were included in this study. Technical advancements of the robot-assisted technique are described. Analyses of patient demographics, electrode implantation accuracy, operation time, and procedure-related complications were performed.

RESULTS

One hundred and sixty-six patients underwent 167 SEEG procedures. The first 141 procedures were performed using a conventional approach involving a Leksell stereotactic system, and the last 26 procedures were robot-assisted. Among the 1726 depth electrodes that were inserted, the median entry point localization error was as follows: conventional (1.0 mm; range, 0.1-33.5 mm) and robot-assisted (1.1 mm; range, 0-4.8 mm) (P = 0.17). The median target point localization error was as follows: conventional (2.8 mm; range, 0.1-49 mm) and robot-assisted (1.8 mm; range, 0-30.3 mm) (P < 0.001). The median operation time was significantly reduced with the robot-assisted workflow (90 min vs. 77.5 min; P < 0.01). Total complication rates were as follows: conventional (17.7%) and robot-assisted (11.5%) (P = 0.57). Major complication rates were 3.5% and 7.7% (P = 0.77), respectively.

CONCLUSIONS

SEEG is a safe and highly accurate method that provides essential guidance for epilepsy surgery. Implementing SEEG in conjunction with multimodal planning systems and robotic devices can further increase safety margin, surgical efficiency, and accuracy.

Visual Stimuli Modulate Local Field Potentials But Drive No High-Frequency Activity in Human Auditory Cortex

Neuroimaging studies suggest cross-sensory visual influences in human auditory cortices (ACs). Whether these influences reflect active visual processing in human ACs, which drives neuronal firing and concurrent broadband high-frequency activity (BHFA; >70 Hz), or whether they merely modulate sound processing is still debatable. Here, we presented auditory, visual, and audiovisual stimuli to 16 participants (7 women, 9 men) with stereo-EEG depth electrodes implanted near ACs for presurgical monitoring. Anatomically normalized group analyses were facilitated by inverse modeling of intracranial source currents. Analyses of intracranial event-related potentials (iERPs) suggested cross-sensory responses to visual stimuli in ACs, which lagged the earliest auditory responses by several tens of milliseconds. Visual stimuli also modulated the phase of intrinsic low-frequency oscillations and triggered 15-30 Hz event-related desynchronization in ACs. However, BHFA, a putative correlate of neuronal firing, was not significantly increased in ACs after visual stimuli, not even when they coincided with auditory stimuli. Intracranial recordings demonstrate cross-sensory modulations, but no indication of active visual processing in human ACs.

Electrophysiological population dynamics reveal context dependencies during decision making in human frontal cortex

Evidence from monkeys and humans suggests that the orbitofrontal cortex (OFC) encodes the subjective value of options under consideration during choice. Data from non-human primates suggests that these value signals are context-dependent, representing subjective value in a way influenced by the decision makers' recent experience. Using electrodes distributed throughout cortical and subcortical structures, human epilepsy patients performed an auction task where they repeatedly reported the subjective values they placed on snack food items. High-gamma activity in many cortical and subcortical sites including the OFC positively correlated with subjective value. Other OFC sites showed signals contextually modulated by the subjective value of previously offered goods-a context dependency predicted by theory but not previously observed in humans. These results suggest that value and value-context signals are simultaneously present but separately represented in human frontal cortical activity.

Cross-task specificity and within-task invariance of cognitive control processes

Cognitive control involves flexibly combining multiple sensory inputs with task-dependent goals during decision making. Several tasks involving conflicting sensory inputs and motor outputs have been proposed to examine cognitive control, including the Stroop, Flanker, and multi-source interference task. Because these tasks have been studied independently, it remains unclear whether the neural signatures of cognitive control reflect abstract control mechanisms or specific combinations of sensory and behavioral aspects of each task. To address these questions, we record invasive neurophysiological signals from 16 patients with pharmacologically intractable epilepsy and compare neural responses within and between tasks. Neural signals differ between incongruent and congruent conditions, showing strong modulation by conflicting task demands. These neural signals are mostly specific to each task, generalizing within a task but not across tasks. These results highlight the complex interplay between sensory inputs, motor outputs, and task demands underlying cognitive control processes.

Stereo-EEG for Epileptogenic Focus Localization in Schizencephaly: A Single-center Experience in Four Patients

OBJECTIVE

Schizencephaly is a congenital cerebral malformation characterized by clefts in the hemispheres of the brain, where variations in semiology often make it difficult to localize epileptogenic focus. Here, we report on a series of patients who underwent stereo-encephalography (SEEG) for epileptogenic focus localization and subsequent SEEG-guided surgical intervention.

METHODS

Four patients (ages 27, 33, 27, 25 years) with a mean seizure history of 16 years (range 8-22 years) were analyzed. Data pertaining to semiology, video encephalography (EEG), magnetic resonance imaging, positron emission tomography, and invasive EEG studies, surgical intervention and post-surgery outcome were collected and analyzed.

RESULTS

All seizure onset zones were within the extent of schizencephaly; however, the limbic system (including the hippocampus, amygdala, cingulate gyrus, or insula) was involved in early spreading. Two patients underwent SEEG-guided radiofrequency thermo-ablation (RFTA) in the seizure onset zone, 1 patient underwent lesionectomy via craniotomy, and 1 underwent neither RFTA nor lesionectomy. At 2 years post-surgery, the outcomes were as follows: Engel grade Ia (n = 2), Ib (n = 1), and III (n = 1).

CONCLUSIONS

This article reports on a precise approach to treating patients with schizencephaly dependent of seizure onset zone and functional cortex mapping. Subsequent SEEG-guided surgical interventions (radiofrequency thermo-ablation and lesionectomy) were shown to reduce seizure frequency, while preserving the neurologic functions in drug-resistant epilepsy patients with schizencephaly.

Validation of the Taiwanese version of the Epilepsy Surgery Satisfaction Questionnaire (Tw-ESSQ-19)

OBJECTIVE

Satisfaction with epilepsy surgery in Mandarin-speaking countries remains unknown. We aimed to validate in our Taiwanese patients an existing instrument to measure patient satisfaction with epilepsy surgery, the 19-item Epilepsy Surgery Satisfaction Questionnaire (ESSQ-19).

METHODS

Consecutive patients with epilepsy who received epilepsy surgery one year earlier in Taipei Veterans General Hospital were recruited and provided clinical and demographic data. The Mandarin version of the ESSQ-19 for the Taiwanese population and eight other questionnaires were completed to assess construct validity. To evaluate the validity and reliability of the tool, the data were analyzed by confirmatory factor analysis, Spearman's rank correlation, and internal consistency analysis.

RESULTS

The study involved 120 patients (70 F/50 M, median age 35 years [IQR = 28-41]). The mean summary score (±SD) of the Tw-ESSQ-19 was 82.5 ± 14.5. The mean scores of the four domains were 90.3 ± 15.4 (surgical complications), 83.2 ± 16.7 (seizure control), 80.1 ± 17.3 (recovery from surgery), and 76.6 ± 18.3 (psychosocial functioning). The questionnaire was shown to have good construct validity with satisfactory goodness-of-fit of the data (standardized root mean square residual = 0.0492; comparative fit index = 0.946). It also demonstrated good discriminant validity (being seizure free [AUC 0.78; 95% CI 0.68-0.89], endorsing depression [AUC 0.84; 95% CI 0.76-0.91], self-rating epilepsy as disabling [AUC 0.71; 95% CI 0.58-0.84], and self-rating epilepsy as severe [AUC 0.78; 95% CI 0.64-0.93]), high internal consistency in four domains (Cronbach's alpha = 0.83-0.96), and no significant floor/ceiling effects of the summary score.

SIGNIFICANCE

The Mandarin version of the ESSQ-19 adapted for the Taiwanese population is a reliable and valid self-reported questionnaire for assessing patient satisfaction with epilepsy surgery.

Strategic infarct location for post-stroke seizure

•

The hot spots of PSS were distributed around the central region of cerebral cortex.

•

We observed differences between the distribution of hot spots among patients with early-PSS and those with late-PSS.

•

The specific regions of the brain are significantly associated with the development of PSS after cerebral infarction.

•

The location of infarction could help clinicians assess the risk of PSS in specific post-stroke stages.

Post-stroke seizure (PSS) can have a strong negative impact on functional recovery after stroke. Researchers have identified numerous risk factors of PSS; however, the relationship between infarction location and PSS remains unclear. We recruited patients who presented with an acute cerebral infarction between 2012 and 2017 and suffered from seizures within 1 year after stroke (PSS group). PSS group was subgrouped into early-PSS and late-PSS groups based on the interval between seizure and stroke. We also recruited an equal number of acute cerebral infarction patients without post-stroke seizures during the follow-up period (Non-PSS group). All brain MRIs from the two groups were processed, whereupon normalized infarct maps from the PSS and Non-PSS groups were compared via voxel- and volumetric-based analyses. A total of 132 subjects were enrolled in the study, including PSS (n = 66, consisting of 31 early-PSS and 35 late-PSS) and Non-PSS (n = 66) patients. No significant differences were observed between the two groups in terms of stroke lateralization or severity. Image analysis revealed that the volume of infarction was larger in the PSS group than in the Non-PSS group; however, the difference did not reach the level of significance. Unlike the Non-PSS group, the PSS group presented hot spots over the left central region, left superior parietal lobule, and right frontal operculum. We observed differences between the distribution of hot spots among patients with early-PSS and those with late-PSS. We found that some brain regions were significantly associated with the development of PSS after ischemic stroke, and these regions differed between cases of early and late PSS. It appears that the location of infarction could help clinicians assess the risk of PSS in specific post-stroke stages.

Clinical characteristics and long-term outcome of cerebral cavernous malformations-related epilepsy

OBJECTIVE

Cerebral cavernous malformations (CCMs) present variably and epileptic seizures are the most common symptom. The factors contributing to cavernoma-related epilepsy (CRE) and drug resistance remain inconclusive. The outcomes of CRE after different treatment modalities have not yet been fully addressed. This study aimed to characterize the clinical features of patients with CRE and the long-term seizure outcomes of medical and surgical treatment strategies.

METHODS

This was a retrospective cohort of 135 patients with CCM who were diagnosed in 2007~2011 and followed up for 93.6 months on average. The patients were divided into drug-resistant epilepsy (DRE) (n = 29), non-DRE (NDRE) (n = 45), and no epilepsy (NE) (n = 61).

RESULTS

Temporal CCM was the factor most strongly associated with the development of both CRE and DRE. The majority of patients with single temporal CCMs had CRE (86.8%, n = 33) and 50% had DRE, whereas only 14.7% (n = 5) with a non-temporal supratentorial CCM had DRE (P < 0.05). The most common lesion site in the DRE group was the mesiotemporal lobe (50%). Multiple CCMs were more frequently observed in the CRE (29.2%) than the NE (11.5%) group (P < 0.05). In patients with CRE, multiple lesions were associated with a higher rebleeding rate (odds ratio: 11.1), particularly in those with DRE (odds ratio: 15.4). The majority of patients who underwent resective surgery for DRE (76.5%, n = 13) achieved ILAE class I and II seizure outcomes even after a long disease course.

SIGNIFICANCE

Temporal CCM not only predisposes to CRE but is also a major risk factor for drug resistance. The mesiotemporal lobe is the most epileptogenic zone. Multiple CCMs are another risk factor for CRE and increase the rebleeding risk in these patients. Surgical resection could provide beneficial long-term seizure outcomes in patients with DRE.

Reliability and validity of the traditional Chinese version of the GAD-7 in Taiwanese patients with epilepsy

BACKGROUND

Generalized anxiety disorder (GAD) is the second most common psychiatric comorbidity of epilepsy. GAD has a negative impact on seizure control, and it is underrecognized. The Generalized Anxiety Disorder 7-item (GAD-7) questionnaire is useful for screening GAD in patients with epilepsy (PWE). This study aimed to validate the traditional Chinese version of the GAD-7 for Taiwanese patients by obtaining data on adult PWE from our hospital.

METHOD

PWE were recruited from the Taipei Veterans General Hospital from April 2017 to January 2020. The mood disorder module of the Mini International Neuropsychiatric Interview (MINI) was used for the psychiatric assessment. The traditional Chinese version of the GAD-7 and the Beck Anxiety Inventory were included as self-rated psychiatric evaluation. To investigate the psychometric properties, internal consistency, external validation, and receiver operator characteristic (ROC) curve analysis were conducted to assess the utility of the Taiwanese version of the GAD-7.

RESULTS

We recruited 109 patients in the present study. Seventeen patients (15.9%) had GAD according to the MINI. The mean GAD-7 score was 10.28 ± 10.68. All the GAD-7 items were significantly and positively associated with the corrected overall GAD-7 score (Cronbach's alpha = 0.928, p < 0.0001). The cut-off point for the GAD-7 in ROC curve analysis was 7. The patients with GAD were more likely to be female and single.

CONCLUSION

The traditional Chinese version of the GAD-7 is a reliable and valid self-report questionnaire for detecting GAD in Taiwanese PWE.

Neuronal intranuclear inclusion disease in patients with adult-onset non-vascular leukoencephalopathy

Neuronal intranuclear inclusion disease (NIID), caused by an expansion of GGC repeats in the 5'-untranslated region of NOTCH2NLC, is an important but underdiagnosed cause of adult-onset leukoencephalopathies. The present study aimed to investigate the prevalence, clinical spectrum, and brain MRI characteristics of NIID in adult-onset nonvascular leukoencephalopathies and assess the diagnostic performance of neuroimaging features. One hundred and sixty-one unrelated Taiwanese patients with genetically undetermined nonvascular leukoencephalopathies were screened for the NOTCH2NLC GGC repeat expansions using fragment analysis, repeat-primed PCR, southern blot analysis and/or nanopore sequencing with Cas9-mediated enrichment. Among them, 32 (19.9%) patients had an expanded NOTCH2NLC allele and diagnosed with NIID. We enrolled another two affected family members from one patient for further analysis. The size of the expanded NOTCH2NLC GGC repeats in the 34 patients ranged from 73 to 323 repeats. Skin biopsy from five patients all showed eosinophilic, p62-positive intranuclear inclusions in the sweat gland cells and dermal adipocytes. Among the 34 NIID patents presenting with nonvascular leukoencephalopathies, the median age at symptom onset was 61 years (range, 41-78 years) and the initial presentations included cognitive decline (44.1%; 15/34), acute encephalitis-like episodes (32.4%; 11/34), limb weakness (11.8%, 4/34), and parkinsonism (11.8%; 4/34). Cognitive decline (64.7%; 22/34) and acute encephalitis-like episodes (55.9%; 19/34) were also the most common overall manifestations. Two-thirds of the patients had either bladder dysfunction or visual disturbance. Comparing the brain MRI features between the NIID patients and individuals with other undetermined leukoencephalopathies, corticomedullary junction curvilinear lesion on diffusion weighted imaging (DWI) was the best biomarker to diagnose NIID with high specificity (98.4%) and sensitivity (88.2%). However, such DWI abnormality was absent in 11.8% of the NIID patients. When only fluid-attenuated inversion recovery images were available, presence of white matter hyperintensity lesions (WMH) either in paravermis or middle cerebellar peduncles also favored the diagnosis of NIID with a specificity of 85.3% and a sensitivity of 76.5%. Among the ten patients' MRI performed within 5 days of the onset of acute encephalitis-like episodes, five showed cortical DWI hyperintense lesions and two revealed focal brain edema. In conclusion, NIID accounts for 19.9% (32/161) of patients with adult-onset genetically undiagnosed nonvascular leukoencephalopathies in Taiwan. Half of the NIID patients ever developed encephalitis-like episodes with restricted diffusion in the cortical regions at the acute stage DWI. Corticomedullary junction hyperintense lesions, WMH in paravermis or middle cerebellar peduncles, bladder dysfunction and visual disturbance are useful hints to diagnose NIID.

Machine Learning Quantitative Analysis of FDG PET Images of Medial Temporal Lobe Epilepsy Patients

PURPOSE

18F-FDG PET is widely used in epilepsy surgery. We established a robust quantitative algorithm for the lateralization of epileptogenic foci and examined the value of machine learning of 18F-FDG PET data in medial temporal lobe epilepsy (MTLE) patients.

PATIENTS AND METHODS

We retrospectively reviewed patients who underwent surgery for MTLE. Three clinicians identified the side of MTLE epileptogenesis by visual inspection. The surgical side was set as the epileptogenic side. Two parcellation paradigms and corresponding atlases (Automated Anatomical Labeling and FreeSurfer aparc + aseg) were used to extract the normalized PET uptake of the regions of interest (ROIs). The lateralization index of the MTLE-associated regions in either hemisphere was calculated. The lateralization indices of each ROI were subjected for machine learning to establish the model for classifying the side of MTLE epileptogenesis.

RESULT

Ninety-three patients were enrolled for training and validation, and another 11 patients were used for testing. The hit rate of lateralization by visual analysis was 75.3%. Among the 23 patients whose MTLE side of epileptogenesis was incorrectly determined or for whom no conclusion was reached by visual analysis, the Automated Anatomical Labeling and aparc + aseg parcellated the associated ROIs on the correctly lateralized MTLE side in 100.0% and 82.6%. In the testing set, lateralization accuracy was 100% in the 2 paradigms.

CONCLUSIONS

Visual analysis of 18F-FDG PET to lateralize MTLE epileptogenesis showed a lower hit rate compared with machine-assisted interpretation. While reviewing 18F-FDG PET images of MTLE patients, considering the regions associated with MTLE resulted in better performance than limiting analysis to hippocampal regions.

Pilot study of focused ultrasound for drug-resistant epilepsy

Objective

The neuromodulatory effects of focused ultrasound (FUS) have been demonstrated in animal epilepsy models; however, the safety and efficacy of FUS in humans with epilepsy have not been well established. Patients with drug‐resistant epilepsy (DRE) undergoing stereo‐electroencephalography (SEEG) provide an opportunity to investigate the neuromodulatory effects of FUS in humans.

Methods

Patients with DRE undergoing SEEG for localization of the seizure onset zone (SOZ) were prospectively enrolled. FUS was delivered to the SOZ using a neuronavigation‐guided FUS system (ceiling spatial‐peak temporal‐average intensity level = 2.8 W/cm², duty cycle = 30%, modulating duration = 10 min). Simultaneous SEEG recordings were obtained during sonication and for 3 days after treatment. Seizures, interictal epileptiform discharges, and adverse events after FUS were monitored.

Results

Six patients met the eligibility criteria and completed FUS treatment. A decrease in seizure frequency was observed in two patients within the 3‐day follow‐up; however, one patient presented an increase in the frequency of subclinical seizures. Posttreatment magnetic resonance imaging revealed neither lesion nor brain edema. Significant changes in spectral power of SEEG were noted at the targeted electrodes during FUS treatment. One patient reported subjective scalp heating during FUS, and one patient developed transient naming and memory impairment that resolved within 3 weeks after FUS.

Significance

FUS can be safely delivered to the SOZ of patients with DRE, resulting in significant changes in spectral power of SEEG. A larger sample cohort and pursuing optimal sonication parameters will be required to elucidate the neuromodulatory effects of FUS when used for seizure control.

Acute withdrawal of new-generation antiepileptic drugs in epilepsy monitoring units: Safety and efficacy

INTRODUCTION

Acute withdrawal of antiepileptic drugs (AEDs) is a safe and effective approach to provoking seizures in order to complete video-electroencephalogram (V-EEG) studies in a timely manner. Previous studies have focused only on withdrawal from conventional AEDs, and the effects of withdrawal from new-generation AEDs have not been extensively studied.

MATERIALS AND METHODS

This study examined adult patients with drug-resistant epilepsy admitted to an epilepsy monitoring unit between 2015 and 2018. Patients were classified according to whether they received conventional AEDs (Con; n = 13) or new-generation AEDs (N-Gen; n = 26). We then compared the effects of withdrawing these two types of AEDs over a period of one week in terms of efficacy (time to complete V-EEG monitoring) and safety, including the incidence of cluster seizures (CS), focal to bilateral tonic-clonic seizures (FBTCS) and status epilepticus (SE).

RESULTS

In both groups, approximately one week was required to complete V-EEG analysis: N-Gen group (5.6 days) and Con group (6.3 days). No differences were observed between the two groups in terms of the median number of seizures, the onset of the 1st seizure, the distribution of CS, FBTCS, or SE. Following acute withdrawal of medication, a high percentage of patients with a history of CS or FBTCS, respectively, presented CS or FBTCS.

CONCLUSIONS

We did not observe significant differences between patients taking new-generation AEDs and those taking conventional AEDs following withdrawal during V-EEG recording. In the current study, we employed a standard protocol for the rapid withdrawal of AEDs (daily dose reduction of 50%), which was sufficient for 80% of patients to complete V-EEG monitoring within one week.

Cingulate gyrus epilepsy: semiology, invasive EEG, and surgical approaches

OBJECTIVE

The semiology of cingulate gyrus epilepsy is varied and may involve the paracentral area, the adjacent limbic system, and/or the orbitofrontal gyrus. Invasive electroencephalography (iEEG) recording is usually required for patients with deeply located epileptogenic foci. This paper reports on the authors' experiences in the diagnosis and surgical treatment of patients with focal epilepsy originating in the cingulate gyrus.

METHODS

Eighteen patients (median age 24 years, range 5-53 years) with a mean seizure history of 23 years (range 2-32 years) were analyzed retrospectively. The results of presurgical evaluation, surgical strategy, and postoperative pathology are reported, as well as follow-up concerning functional morbidity and seizures (median follow-up 7 years, range 2-12 years).

RESULTS

Patients with cingulate gyrus epilepsy presented with a variety of semiologies and scalp EEG patterns. Prior to ictal onset, 11 (61%) of the patients presented with aura. Initial ictal symptoms included limb posturing in 12 (67%), vocalization in 5, and hypermotor movement in 4. In most patients (n = 16, 89%), ictal EEG presented as widespread patterns with bilateral hemispheric origin, as well as muscle artifacts obscuring the onset of EEG during the ictal period in 11 patients. Among the 18 patients who underwent resection, the pathology revealed mild malformation of cortical development in 2, focal cortical dysplasia (FCD) Ib in 4, FCD IIa in 4, FCD IIb in 4, astrocytoma in 1, ganglioglioma in 1, and gliosis in 2. The seizure outcome after surgery was satisfactory: Engel class IA in 12 patients, IIB in 3, IIIA in 1, IIIB in 1, and IVB in 1 at the 2-year follow-up.

CONCLUSIONS

In this study, the authors exploited the improved access to the cingulate epileptogenic network made possible by the use of 3D electrodes implanted using stereoelectroencephalography methodology. Under iEEG recording and intraoperative neuromonitoring, epilepsy surgery on lesions in the cingulate gyrus can result in good outcomes in terms of seizure recurrence and the incidence of postoperative permanent deficits.

Distributed source modeling of intracranial stereoelectro-encephalographic measurements

Intracranial stereoelectroencephalography (sEEG) provides unsurpassed sensitivity and specificity for human neurophysiology. However, functional mapping of brain functions has been limited because the implantations have sparse coverage and differ greatly across individuals. Here, we developed a distributed, anatomically realistic sEEG source-modeling approach for within- and between-subject analyses. In addition to intracranial event-related potentials (iERP), we estimated the sources of high broadband gamma activity (HBBG), a putative correlate of local neural firing. Our novel approach accounted for a significant portion of the variance of the sEEG measurements in leave-one-out cross-validation. After logarithmic transformations, the sensitivity and signal-to-noise ratio were linearly inversely related to the minimal distance between the brain location and electrode contacts (slope≈-3.6). The signa-to-noise ratio and sensitivity in the thalamus and brain stem were comparable to those locations at the vicinity of electrode contact implantation. The HGGB source estimates were remarkably consistent with analyses of intracranial-contact data. In conclusion, distributed sEEG source modeling provides a powerful neuroimaging tool, which facilitates anatomically-normalized functional mapping of human brain using both iERP and HBBG data.

Outcomes of hippocampus-sparing lesionectomy for temporal lobe epilepsy and the significance of intraoperative hippocampography

OBJECTIVES

We investigated hippocampal-sparing lesionectomy (HSL) outcomes in temporal lobe epilepsy (TLE) and the significance of high-frequency oscillations (HFOs) detected by hippocampography in HSL.

METHODS

We retrospectively reviewed data from patients who underwent HSL for lesional TLE. Patients were included when MRI confirmed (i) a lesion limited to the temporal lobe with normal hippocampi preoperatively and (ii) hippocampal integrity postoperatively. Factors possibly related to outcomes were collected. Intraoperative hippocampography was reviewed, and spikes, ripples, and fast ripples were marked. Seizure outcomes were tracked ≥ 2 years. Postoperative neuropsychological tests were performed and analyzed.

RESULTS

We included 67 patients (35 males/32 females, median age at surgery 28 years, 57 seizure-free). Complete resection was significantly associated with being seizure-free without aura, an outcome achieved by 32 (69.6%) patients with complete resection vs 1 (12.5%) with incomplete resection (p = 0.004). Spikes/ripples/fast ripples appeared frequently in the hippocampus, occurring in 86.4%/82.4%/75.0% of cases before resection and 76.7%/78.1%/63.0% after resection. The presence and rate were unconnected to seizure outcome. Postoperative neuropsychological outcomes in intelligence and visual memory improved overall.

CONCLUSIONS

HSL in lesional TLE can produce satisfactory seizure and cognitive outcomes. Intraoperative hippocampography-guided resection of apparently normal hippocampi should be performed cautiously and might not be necessary.

SIGNIFICANCE

This study provided evidence in decision making for patients with lesional TLE with a radiologically normal hippocampus.

Reliability and validity of the Taiwanese version of the Neurological Disorders Depression Inventory for Epilepsy (Tw-NDDI-E)

INTRODUCTION

Depression is the most commonly seen psychiatric co-morbidity of epilepsy. Depression in patients with epilepsy (PWE) is underrecognized. The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is a useful tool to screen for major depressive episodes (MDEs) in PWE. This study validated the Taiwanese version of the NDDI-E using data from adult PWE in our hospital.

METHOD

PWE were recruited from the Taipei Veterans General Hospital from April 2017 to December 2019. The Chinese version of the NDDI-E for the Taiwanese population and the Beck Depression Inventory-II (BDI-II) were completed as part of the self-rated psychiatric assessments. The mood disorder module of the Mini International Neuropsychiatric Interview (MINI) was completed as part of the psychiatric assessment before the self-rated assessment. Internal consistency, external validation, and receiver operator characteristic (ROC) curve analysis were used to assess the utility of the Taiwanese version of the NDDI-E.

RESULTS

We recruited 109 patients during the 33-month study period. The mean age was 33.1 ± 8.94 years old. The mean NDDI-E score was 12.32 ± 4.96. The mean BDI-II score was 13.26 ± 12.77. All NDDI-E items were significantly positively associated with the corrected overall NDDI-E score (Cronbach's alpha = 0.902, r = 0.825, p < 0.0001). The cut-off point for the NDDI-E determined with receiver operating characteristic (ROC) curve analysis is 15 (sensitivity = 85.0%, specificity = 87.64%).

CONCLUSION

The Chinese version of the NDDI-E adapted for the Taiwanese population is a reliable and valid self-reported questionnaire for detecting MDE in Taiwanese PWE.

Procedure-Related Temporal Infarct After Retractorless Transsylvian Selective Amygdalohippocampectomy and Impact on 2-Year Epilepsy Outcome

BACKGROUND

Selective amygdalohippocampectomy (SAH) is designed to treat patients with mesial temporal lobe epilepsy (MTLE).

OBJECTIVE

To determine the volume and impact of temporal lobe infarction after retractorless transsylvian SAH (en bloc resection of the hippocampus) that have not been reported.

METHODS

A retrospective analysis of patients treated with retractorless transsylvian SAH. Infarctions were detected by magnetic resonance imaging (MRI) within the first week after the operation. Neuropsychological testing was performed preoperatively and 6 mo later. Seizure outcome was evaluated 2 yr after epilepsy surgery.

RESULTS

Between 2010 and 2014, a total of 30 patients were included in this study. Analysis of postoperative MRI showed the following: (1) mean removal volume of the hippocampus-parahippocampus was 5.72 cm3, and (2) mean volumes of temporal and insular infarctions were 1.71 and 0.25 cm3, respectively. Twenty-five patients (83.3%) were free of disabling seizures (Engel class I) at 2 yr of outcome. Neuropsychological testing revealed improvement in Perceptual Organization Index (P = .036) and verbal paired associates II (P = .014) after the operation. Neither infarction volume nor removal volume was related to epilepsy outcome in linear regression model.

CONCLUSION

Transsylvian SAH has comparable seizure outcomes but bears inherent risks of vasospasm/vascular injury. Immediate postoperative small infarction volume around resection cavity or along surgical corridor was noticed after retractorless transsylvian SAH, which did not cause neuropsychological deteriorations, in contrast to previous study with the use of self-sustaining rigid retraction system. Further study should be performed to compare procedure-related infarctions and their impacts on neuropsychological outcomes in different selective approaches.

Establishment of feline in-house reference intervals for hematologic and biochemical parameters and potential age-related differences

Reference intervals (RIs) are one of the essential elements in the procedure of disease diagnosis. This is especially true for feline species in which RI is less available than in canine species. RIs are affected by biological, geographical and instrumental factors, yet published RIs with incomplete background are popularly used. Inappropriate interpretations of RIs may affect classification of disease and subsequent treatment. In this study, we demonstrated the step-by-step establishment of feline RIs following the American Society for Veterinary Clinical Pathology (ASVCP) reference interval guideline. A total of 51 parameters were examined, including 20 hematology and 31 biochemistry parameters, and the results were compared to one local RI and two foreign RIs. Overall, about 29% (10/35) of tested parameters were different form local RIs and 60% (30/50) were different from the two foreign RIs, highlighting geographical variations. A higher upper reference limit (URL) in red blood cell count (RBC), hematocrit (Hct), Hemoglobin (Hgb), albumin, creatinine and lower URL in potassium and white blood cell count (WBC) were identified, which may impact the interpretation. In addition, statistical analysis of age and gender were factored separately and indicated that 10 parameters were significantly higher in the adult group. For the impact of gender, percentage of basophil and total iron-binding capacity (TIBC) were lower in female and male cats, respectively. In conclusion, we have demonstrated that it is desirable to establish in-house RIs or RIs of local sources. An age specific RI for the geriatric feline population is advisable for better diagnosis and monitoring the disease.

Social functioning and health-related quality of life trajectories in people with epilepsy after epilepsy surgery

OBJECTIVE

An improvement in quality of life (QoL) over time after epilepsy surgery has been demonstrated in people with epilepsy; however, social functioning has been less investigated. We conducted this study to examine whether postsurgical improvement is parallel between QoL and social functioning in patients with epilepsy.

METHODS

We retrospectively reviewed patients who underwent epilepsy surgery. All participants completed a comprehensive neuropsychological assessment, the Quality of Life in Epilepsy Inventory (QOLIE-89) questionnaire, and the Social and Occupational Functioning Scale for Epilepsy (SOFSE) before surgery and at 3 months, 6 months, and 1 year after surgery. Demographic and epilepsy-related information was also collected. Generalized estimating equations with identity links were used to model the QOLIE-89 and SOFSE over time and possible associated factors. A p < 0.05 was considered statistically significant.

RESULTS

A total of 76 patients, including 36 males and 43 females aged 18 to 62 years were collected. Both total QOLIE-89 and overall SOFSE improved over time after epilepsy surgery (adjusted p value < 0.001 and 0.002, respectively, with Bonferroni's correction). Total QOLIE-89 improved 3 months after surgery, while overall SOFSE showed no significant improvement until 6 months after surgery. The presurgical Full-Scale Intelligence Quotient (FSIQ) of the Wechsler Adult Intelligence Scale-III and years of education were significantly associated with time-dependent improvement for both total QOLIE-89 and overall SOFSE (p value < 0.001). At one year after surgery, overall SOFSE and total QOLIE-89 scores were significantly higher in the seizure-free group than in the nonseizure-free group (p value = 0.040 and 0.032, respectively).

CONCLUSION

Social functioning significantly improved in people with epilepsy after surgery as QoL, but it took more time to exhibit improvement. People with better FSIQ and more years of education had better improvement in social functioning over time. The early intervention of rehabilitation programs after epilepsy surgery might be necessary to facilitate the improvement in social functioning.

Gamma Knife radiosurgery for cerebral cavernous malformation

This is a retrospective study examining the efficacy and safety of Gamma Knife radiosurgery (GKS) in treating patients with cerebral cavernous malformations (CCMs). Between 1993 and 2018, 261 patients with 331 symptomatic CCMs were treated by GKS. The median age was 39.9 years and females were predominant (54%). The median volume of CCMs was 3.1 mL. The median margin dose was 11.9 Gy treat to a median isodose level of 59%. Median clinical and imaging follow-up times were 69 and 61 months, respectively. After the initial hemorrhage that led to CCM diagnosis, 136 hemorrhages occurred in the period prior to GKS (annual incidence = 23.6%). After GKS, 15 symptomatic hemorrhages occurred within the first 2 years of follow-up (annual incidence = 3.22%), and 37 symptomatic hemorrhages occurred after the first 2 years of follow-up (annual incidence = 3.16%). Symptomatic radiation-induced complication was encountered in 8 patients (3.1%). Mortality related to GKS occurred in 1 patient (0.4%). In conclusion, GKS decreased the risk of hemorrhage in CCM patients presenting with symptomatic hemorrhage. GKS is a viable alternative treatment option for patients with surgically-inaccessible CCMs or significant medical comorbidities.

Ictal networks of temporal lobe epilepsy: views from high-frequency oscillations in stereoelectroencephalography

OBJECTIVEIn this study, the authors investigated high-frequency oscillation (HFO) networks during seizures in order to determine how HFOs spread from the focal cerebral cortex and become synchronized across various areas of the brain.METHODSAll data were obtained from stereoelectroencephalography (SEEG) signals in patients with drug-resistant temporal lobe epilepsy (TLE). The authors calculated intercontact cross-coefficients between all pairs of contacts to construct HFO networks in 20 seizures that occurred in 5 patients. They then calculated HFO network topology metrics (i.e., network density and component size) after normalizing seizure duration data by dividing each seizure into 10 intervals of equal length (labeled I1-I10).RESULTSFrom the perspective of the dynamic topologies of cortical and subcortical HFO networks, the authors observed a significant increase in network density during intervals I5-I10. A significant increase was also observed in overall energy during intervals I3-I8. The results of subnetwork analysis revealed that the number of components continuously decreased following the onset of seizures, and those results were statistically significant during intervals I3-I10. Furthermore, the majority of nodes were connected to a single dominant component during the propagation of seizures, and the percentage of nodes within the largest component grew significantly until seizure termination.CONCLUSIONSThe consistent topological changes that the authors observed suggest that TLE is affected by common epileptogenic patterns. Indeed, the findings help to elucidate the epileptogenic network that characterizes TLE, which may be of interest to researchers and physicians working to improve treatment modalities for epilepsy, including resection, cortical stimulation, and neuromodulation treatments that are responsive to network topologies.

Aberrant Sensory Gating of the Primary Somatosensory Cortex Contributes to the Motor Circuit Dysfunction in Paroxysmal Kinesigenic Dyskinesia

Paroxysmal kinesigenic dyskinesia (PKD) is conventionally regarded as a movement disorder (MD) and characterized by episodic hyperkinesia by sudden movements. However, patients of PKD often have sensory aura and respond excellently to antiepileptic agents. PRRT2 mutations, the most common genetic etiology of PKD, could cause epilepsy syndromes as well. Standing in the twilight zone between MDs and epilepsy, the pathogenesis of PKD is unclear. Gamma oscillations arise from the inhibitory interneurons which are crucial in the thalamocortical circuits. The role of synchronized gamma oscillations in sensory gating is an important mechanism of automatic cortical inhibition. The patterns of gamma oscillations have been used to characterize neurophysiological features of many neurological diseases, including epilepsy and MDs. This study was aimed to investigate the features of gamma synchronizations in PKD. In the paired-pulse electrical-stimulation task, we recorded the magnetoencephalographic data with distributed source modeling and time-frequency analysis in 19 patients of newly-diagnosed PKD without receiving pharmacotherapy and 18 healthy controls. In combination with the magnetic resonance imaging, the source of gamma oscillations was localized in the primary somatosensory cortex. Somatosensory evoked fields of PKD patients had a reduced peak frequency (p < 0.001 for the first and the second response) and a prolonged peak latency (the first response p = 0.02, the second response p = 0.002), indicating the synchronization of gamma oscillation is significantly attenuated. The power ratio between two responses was much higher in the PKD group (p = 0.013), indicating the incompetence of activity suppression. Aberrant gamma synchronizations revealed the defective sensory gating of the somatosensory area contributes the pathogenesis of PKD. Our findings documented disinhibited cortical function is a pathomechanism common to PKD and epilepsy, thus rationalized the clinical overlaps of these two diseases and the therapeutic effect of antiepileptic agents for PKD. There is a greater reduction of the peak gamma frequency in PRRT2-related PKD than the non-PRRT PKD group (p = 0.028 for the first response, p = 0.004 for the second response). Loss-of-function PRRT2 mutations could lead to synaptic dysfunction. The disinhibiton change on neurophysiology reflected the impacts of PRRT2 mutations on human neurophysiology.

Plasma indoxyl sulfate concentration predicts progression of chronic kidney disease in dogs and cats

Indoxyl sulfate is a protein-bound uremic toxin that increases as the severity of impaired renal function increases in humans, laboratory animals, dogs and cats. An elevation of indoxyl sulfate is related to prognosis among people with chronic kidney disease. However, whether indoxyl sulfate is able to predict the progression of chronic kidney disease in dogs and cats has not been previously studied. In the present study, 58 cats and 36 dogs with chronic kidney disease were enrolled. Plasma indoxyl sulfate was measured by high performance liquid chromatography. Renal progression was defined as an increase by one International Renal Interest Society (IRIS) stage and/or a rise in serum creatinine concentration of 0.5mg/dL during the same stage within a 3-month period. Compared with the non-progression groups, across different stages of renal failure, the baseline plasma indoxyl sulfate concentration was increased in the renal progression group (P<0.05), especially for IRIS stages 2 and 3 animals. The area under the receiver operator characteristic curves of indoxyl sulfate, when predicting renal progression, was above 0.75 for both dogs and cats. Indoxyl sulfate concentrations were also correlated with the increase of blood urea nitrogen, serum creatinine, and phosphate and the decrease of hematocrit among cats; while in dogs, concentrations were only correlated with the increase of phosphate concentrations. Indoxyl sulfate served as a biomarker of progression risk in dogs and cats with chronic kidney disease.

Exploring resting-state EEG complexity before migraine attacks

Objective

Entropy-based approaches to understanding the temporal dynamics of complexity have revealed novel insights into various brain activities. Herein, electroencephalogram complexity before migraine attacks was examined using an inherent fuzzy entropy approach, allowing the development of an electroencephalogram-based classification model to recognize the difference between interictal and preictal phases.

Methods

Forty patients with migraine without aura and 40 age-matched normal control subjects were recruited, and the resting-state electroencephalogram signals of their prefrontal and occipital areas were prospectively collected. The migraine phases were defined based on the headache diary, and the preictal phase was defined as within 72 hours before a migraine attack.

Results

The electroencephalogram complexity of patients in the preictal phase, which resembled that of normal control subjects, was significantly higher than that of patients in the interictal phase in the prefrontal area (FDR-adjusted p < 0.05) but not in the occipital area. The measurement of test-retest reliability (n = 8) using the intra-class correlation coefficient was good with r1 = 0.73 ( p = 0.01). Furthermore, the classification model, support vector machine, showed the highest accuracy (76 ± 4%) for classifying interictal and preictal phases using the prefrontal electroencephalogram complexity.

Conclusion

Entropy-based analytical methods identified enhancement or “normalization” of frontal electroencephalogram complexity during the preictal phase compared with the interictal phase. This classification model, using this complexity feature, may have the potential to provide a preictal alert to migraine without aura patients.

Selective Serotonin Reuptake Inhibitors and Poststroke Epilepsy: A Population-Based Nationwide Study

OBJECTIVE

To investigate the effects of selective serotonin reuptake inhibitors (SSRIs) on poststroke epilepsy in a population-based nationwide study.

PATIENTS AND METHODS

The SSRI group included patients who received a stroke diagnosis from January 1, 2000, through December 31, 2009, and were prescribed SSRIs after stroke. The non-SSRI group enrolled patients with stroke who were not prescribed SSRIs from the Taiwan National Health Insurance Research Database and used propensity score matching based on the index year, duration time, sex, age, type of stroke, and duration of hospitalization. Cox proportional hazards models were used to estimate the risk of epilepsy between the SSRI and comparison groups.

RESULTS

A total of 4688 patients with stroke (2344 in each of the SSRI and non-SSRI cohorts) were enrolled. The cumulative incidence of epilepsy in the SSRI group was significantly higher than that in the comparison group (log-rank P<.001). In the SSRI group, the risk of poststroke epilepsy increased 2.45-fold (95% CI, 1.69- to 3.57-fold) compared with that in the comparison group. Furthermore, the risk of poststroke epilepsy increased with the defined daily dose of SSRIs. For patients with ischemic stroke, SSRIs users had a 2.74-fold higher risk of epilepsy than non users (95% CI, 1.79- to 4.22-fold).

CONCLUSION

In this study, SSRI users had a higher risk of poststroke epilepsy than nonusers. Further study is warranted to investigate the causal relationship between SSRI exposure and poststroke epilepsy.

Cascade of neural processing orchestrates cognitive control in human frontal cortex

Rapid and flexible interpretation of conflicting sensory inputs in the context of current goals is a critical component of cognitive control that is orchestrated by frontal cortex. The relative roles of distinct subregions within frontal cortex are poorly understood. To examine the dynamics underlying cognitive control across frontal regions, we took advantage of the spatiotemporal resolution of intracranial recordings in epilepsy patients while subjects resolved color-word conflict. We observed differential activity preceding the behavioral responses to conflict trials throughout frontal cortex; this activity was correlated with behavioral reaction times. These signals emerged first in anterior cingulate cortex (ACC) before dorsolateral prefrontal cortex (dlPFC), followed by medial frontal cortex (mFC) and then by orbitofrontal cortex (OFC). These results disassociate the frontal subregions based on their dynamics, and suggest a temporal hierarchy for cognitive control in human cortex.

DOI:http://dx.doi.org/10.7554/eLife.12352.001

The brain adapts to control our behavior in different ways depending on the specific situation, which is particularly useful when deciding how to interpret conflicting sets of information. The 'Stroop task' is a classic demonstration of this process. In this task, individuals are shown words where the color and the meaning of the text conflict – for example, the word 'green' is written in blue. When asked what the color of the text is, individuals must suppress the instinct to read the word. This causes them to make more mistakes and take longer to decide on an answer than when they perform the same task using words that have no conflict (for example, when “red” is written in red).

Previous work has suggested that several regions within part of the brain called the frontal cortex play a role in this cognitive control process. However, the relative contributions of each of these regions, and the order in which they are activated, remain unclear. This is in part due to the fact that accurately measuring the electrical activity of the frontal cortex requires implanting electrodes into the brain.

Tang et al. took advantage of a rare opportunity to record this activity from a group of patients who had electrodes implanted in their frontal cortex to treat epilepsy. The electrical signals recorded by these electrodes as the subjects performed the Stroop task revealed that four regions in the frontal cortex altered their activity during trials where the color and the meaning of a word conflicted. These responses corresponded with the subject’s reaction time, changed depending on the exact nature of the task, and even reflected the subjects’ errors. These responses arose at different times in different regions, allowing Tang et al. to suggest how signals flow through the frontal cortex during cognitive control.

In the future it will be important to further understand how the regions of the frontal cortex identified by Tang et al. interact with each other and to establish their roles in cognitive control. These observations could then be used to produce a theoretical framework that describes how the brain adapts behavior to different circumstances.

DOI:http://dx.doi.org/10.7554/eLife.12352.002

Detection of indoxyl sulfate levels in dogs and cats suffering from naturally occurring kidney diseases

Indoxyl sulfate (IS), a protein-bound uraemic toxin, has been found to accumulate in the serum of people with renal diseases and is associated with free radical induction, nephrotoxicity cardiovascular toxicity, and osteoblast cytotoxicity. Although IS has been studied in humans and in experimental models, the role of IS in dogs and cats with kidney disease has not been investigated. A high performance liquid chromatography system was applied to detect plasma IS concentrations in non-azotaemic animals (63 dogs, 16 cats) and in animals with renal azotaemia (66 dogs, 69 cats). The IS levels of azotaemic animals were significantly higher (P <0.01) than those of non-azotaemic animals (median [IQR] 20.4 (9.5) mg/L vs. 7.2 (8.8) mg/L for dogs; median [IQR] 21 (18.9) mg/L vs. 14.8 (12.3) mg/L for cats). The IS level was significantly correlated with blood urea nitrogen, serum creatinine and phosphate concentrations. Dogs with acute kidney injury had significantly higher IS levels (P <0.01) than those with chronic kidney diseases (CKD) (median [IQR] 57.7 (40.8) mg/L vs. 17.7 (25.1) mg/L). When CKD was graded using the International Renal Interest Society (IRIS) staging system, IS levels were correlated with CKD severity in both dogs and cats. The IS concentration is directly related to loss of renal function. Further studies are necessary to determine whether measurement of IS provides any additional diagnostic or prognostic information in dogs and cats with kidney disease.

Associations between serum total bilirubin levels and functional dependence in the elderly

BACKGROUND

Many studies support the role of bilirubin as a cytoprotector in chronic inflammatory diseases, such as stroke and atherosclerosis.

AIM

To investigate the relationship between serum total bilirubin levels and functional dependence in older adults.

METHODS

Data from the National Health and Nutrition Examination Survey (1999-2002) pertaining to 2235 old adults were analysed. All participants had given a household interview, providing information of five major domains on self-reported functional status (activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility and general physical activities), had completed serum total bilirubin measurement, and a questionnaire regarding personal health. Poor performance was defined as experiencing difficulty with one or more items in a given domain. Functional dependence was defined as having three or more poor performances in the five major domains. Multiple logistic regression was performed together with quartile-based stratified odds ratio (OR) comparison and trend tests.

RESULTS

The OR of functional dependence for each standard deviation increment in the serum total bilirubin level was 0.56 (P = 0.002). After additional adjustment, the inverse association remained essentially unchanged. In quartile-based analysis, participants with higher quartiles of serum total bilirubin tended to have lower ORs of functional dependence. The trends of lower likelihood of functional dependence across increasing quartiles of the serum total bilirubin level were statistically significant (P < 0.05 for all trends).

CONCLUSIONS

Higher serum total bilirubin levels were associated with lower likelihood of functional dependence in older adults.

Monocyte chemoattractant protein-1 affects migration of hippocampal neural progenitors following status epilepticus in rats

BACKGROUND

Epilepsy is a common brain disorder characterized by a chronic predisposition to generate spontaneous seizures. The mechanisms for epilepsy formation remain unknown. A growing body of evidence suggests the involvement of inflammatory processes in epileptogenesis. In the present study, we investigated the involvement of monocyte chemoattractant protein-1 (MCP-1) in aberrant migration of hippocampal progenitors in rats after the insult of status epilepticus (SE).

METHODS

SE was induced with pilocarpine in Sprague-Dawley rats. Transcriptional expression of MCP-1 in the dentate gyrus (DG) was measured using quantitative real-time PCR. From 1 to 28 days after SE, the temporal profiles of MCP-1 protein expression in DG were evaluated using enzyme-linked immunosorbent assay. Chemokine (C-C motif) receptor 2 (CCR2) expression in doublecortin-positive neuronal progenitors was examined using double-labeling immunohistochemistry. The involvement of MCP-1/CCR2 signaling in aberrant neuronal progenitor migration in the epileptic hippocampus was assessed in the SE rats using a CCR2 antagonist, RS102895, and the ectopic migration of neuronal progenitors was determined using Prox1/doublecortin double immunostaining.

RESULTS

After SE, MCP-1 gene was significantly upregulated and its corresponding protein expression in the DG was significantly increased on days 1 and 3. Some hilar ectopic progenitor cells of SE rats expressed the MCP-1 receptor, CCR2. Notably, the ectopic migration of neuronal progenitors into hilus was attenuated by a blockade of the MCP-1/CCR2 interaction with a selective CCR2 inhibitor, RS102895.

CONCLUSIONS

An increase in dentate MCP-1 is associated with seizure-induced aberrant migration of neuronal progenitors through the interaction with CCR2. The upregulation of MCP-1 after an insult of SE may play a role in the generation of epilepsy.

Treatment-seeking behavior of people with epilepsy in Taiwan: a preliminary study

To understand the treatment-seeking behavior of people with epilepsy (PWE), 403 PWE were surveyed using structured face-to-face interviews. Nearly half (49.1%) of them had previously tried complementary and alternative medicine (CAM); traditional Chinese medicine (51.5%) and temple worship (48.0%) were the most frequently used forms of CAM. In the 155 patients with adult-onset epilepsy, seeking CAM was substantially more common among females (OR=2.11, 95% CI=1.05-4.24, P=0.036), patients with frequent seizures (OR=2.68, 95% CI=1.30-5.53, P=0.008), patients with less educated parents (OR=2.16, 95% CI=1.06-4.41, P=0.034), and patients with religious beliefs (OR=2.84, 95% CI=1.23-6.56, P=0.015). In the 248 patients with childhood-onset epilepsy, frequent seizures (OR=2.23, 95% CI=1.32-3.77, P=0.003) and lower level of parental education (OR=2.71, 95% CI=1.45-5.06, P=0.002) were significantly associated with CAM use. The patients who seek CAM before receiving conventional medical treatment decreased after implementation of the National Health Insurance (NHI) (34/188 before NHI vs 22/215 after NHI, P=0.023). This study showed that the prevalence of CAM use by PWE in Taiwan is high and that a convenient NHI program can affect treatment-seeking behavior.

Cultural condition affecting the growth and production of β-galactosidase by Bifidobacterium longum CCRC 15708 in a jar fermenter

In the present study, the growth and production of beta-galactosidase by Bifidobacterium longum CCRC 15708 in a 5-L jar fermenter as influenced by cultivation temperature (27-42 degrees C), medium pH (4.5-7.5) and agitation speed (5-200 rpm) were evaluated. In general, it was found that a cultivation temperature of 37 degrees C proved optimal for both growth and beta-galactosidase production by the test organism. Although the growth of the test organism was the highest in the culture with pH controlled at 4.5-6.5, the culture with pH controlled at 6.5 resulted in the highest production of beta-galactosidase. Further, agitation at 100 rpm or more was found to enhance both the growth and production of beta-galactosidase. Fermentation conducted in a jar fermenter having the pH of the culture medium, the cultivation temperature, and the agitation speed controlled at 6.5, 37 degrees C, and 100 rpm, respectively, a maximum beta-galactosidase activity of 36.7 U/ml and a maximum transgalactosylation activity of 0.49 U/ml was achieved in 10 h of fermentation. There are ca 2.0 and 12.3 fold greater than the reported maximum beta-galactosidase and transgalactosylation activity, respectively, produced by B. longum CCRC 15708 in a flask culture system.

Enzymatic production of galactooligosaccharides by beta-galactosidase from Bifidobacterium longum BCRC 15708

The production of galactooligosaccharides (GOSs) by transgalactosylation using beta-galactosidase from Bifidobacterium longum BCRC 15708 was studied. Other than lactose, galactose, and glucose, two types of GOSs, tri- and tetrasaccharides, were formed after beta-galactosidase action on 40% lactose. Trisaccharides were the major type of GOS formed. Generally, an increase of the initial lactose concentration in the reaction mixture resulted in a higher GOS production. A maximum yield of 32.5% (w/w) GOSs could be achieved from 40% lactose solution at 45 degrees C, pH 6.8, when the lactose conversion was 59.4%. The corresponding productivity of GOSs was 13.0 g/(L.h). Transgalactosylation activity of beta-galactosidase from a test organism showed a relatively lower sensitivity toward glucose and galactose than that from other organisms. The addition of 5% or 10% glucose or galactose to the reaction mixture did not significantly (p>0.05) reduce the transgalactosylation reaction of beta-galactosidase.

Study on the species-specificity of Isospora michaelbakeri by experimental infection

Isospora michaelbakeri is one of the Isospora species most commonly found in the wild field, which can cause severe infection and mortality in young sparrows. In this study, we selected I. michaelbakeri (Chung Hsing strain) as a pathogen to orally inoculate russet sparrows (Passer rutilans), spotted munia (Lonchura punctulata), canary (Serinus canaria), Java sparrows (Padda oryzivora), chicken (Gallus domesticus), ducks (Anas platyrhynchos) and BALB/c mice. The results indicated that I. michaelbakeri infected only russet sparrows. Infected sparrows displayed lethargy, muscular weakness and fluffy feathers, followed by rapid death. Liver and spleen enlargement was seen in the infected birds. Schizonts were identified in thin smears from the venous blood, enlarged livers and spleens. Histopathological examination revealed schizonts and merozoites from the liver and spleen of infected russet sparrows, but not from other species experimentally inoculated with I. michaelbakeri in the present study.

Characterization of Bacterial Susceptibility Isolates in Sixteen Dairy Farms in Taiwan

Bacteria were isolated from dairy cows, dairy farm environments, and dairy workers in 2 geographically different areas of eastern and northern Taiwan. Isolates were evaluated for antimicrobial susceptibility and the phylogenetics of isolated Escherichia coli O157:H7 were characterized. A total of 1,346 bacteria were identified, including 226 E. coli, 30 Pseudomonas spp. (7 Pseudomonas aeruginosa), 259 other gram-negative bacteria, 271 Enterococcus spp., 314 Staphylococcus spp., 195 Streptococcus spp., and 51 other gram-positive bacteria. Among them, 88% (1,184/1,346) of the isolates were resistant to sulfadimethoxine. The percentages of gram-negative bacteria resistant to oxy-tetracycline and streptomycin were 48% (249/515) and 78% (404/515), respectively. Gram-positive bacteria isolated from eastern Taiwan, the least polluted region of Taiwan, were found to have greater antimicrobial resistance than those isolated from northern Taiwan. Two E. coli O157:H7 from 2 different geographical areas were isolated. Both were vt2-positive but vt1-negative and had phylogenetic similarities of 82 and 67%, respectively, compared with previous isolates. Information on antimicrobial susceptibility revealed from this dairy farm survey may serve as a baseline for future studies and may also highlight the need to formulate better regulation strategies for the safe use of antimicrobials on food-producing farms.

Production of β-galactosidase by Bifidobacteria as influenced by various culture conditions

Beta-Galactosidase production by Bifidobacterium longum CCRC 15708, Bifidobacterium longum B6 and Bifidobacterium infantis CCRC 14633 was first examined with B. longum CCRC 15708 showing the highest production of beta-galactosidase and the highest specific activity. Further study with B. longum CCRC 15708 revealed that the highest level of beta-galactosidase was produced with lactose and yeast extract as carbon and nitrogen sources, respectively. Optimal enzyme production occurred at an initial pH of 6.5 and at 37 degrees C. Under these optimum culture conditions, a maximumbeta-galactosidase activity of 18.6 U/ml could be obtained after 16 h of fermentation in a medium contain 4% lactose, 3.5% yeast extract, 0.3% K2HPO4, 0.1% KH2PO4, 0.05% MgSO4.7H2O and 0.03% L-cysteine. The highest transgalactosylation activity was also detected in this culture after 14-16 h of fermentation.

Risk factors for cumulative mortality in broiler chicken flocks in the first week of life in Taiwan

(1) Factors influencing the survival of chickens in the first week of life in Taiwan were identified by modelling data from 63% of the annual national broiler production database (4769 broiler flocks). (2) Broiler chicks raised in rooms with open-curtain ventilation had the lowest mean first week cumulative mortality (CM), 1.30%, relative to those raised in rooms with negative pressure ventilation (1.42%) and water-cooled ventilation (1.37%). Increasing flock size reduced the CM. Broiler chicks shipped distances within 50 km had the lowest CM (1.22%), while broiler chicks raised in mountain areas showed the highest CM (1.65%). (3) Multiple regression analysis results indicate that ventilation type, flock size, shipping distance and delivery route influence CM in broiler chickens. Broiler chicks kept in rooms with negative pressure ventilation have an 11.22% greater CM compared to those in rooms with open-curtain ventilation. For each 1000-chicken increase in flock size, CM is reduced by 0.12%. For each kilometre increase in shipping distance, CM increases by 0.05%. Broiler chicks delivered via mountain routes show a 9.48% increase in CM compared to delivery via flat terrain. (4) Negative pressure ventilation and delivery via mountain routes are the most critical factors affecting the survival of chicks up to one week old.

Congener-specific polychlorinated biphenyls in cetaceans from Taiwan waters

During 2000 to 2001, a total of 73 blubber samples from 13 species of stranded or accidentally captured cetaceans were collected from Taiwan coastal waters for polychlorinated biphenyl (PCB) analysis. After homogenization, saponification, liquid-liquid extraction, and silica-gel solid-phase extraction, PCB concentrations were determined by gas chromatography/mass spectrometry. Total concentrations of 19 PCB congeners (SigmaPCBs) were between 0.23 microg/g lipid weight of Risso's dolphin to 33.73 microg/g lipid weight of rough-toothed dolphin. Pentachlorobiphenyls, hexachlorobiphenyls and heptachlorobiphenyls were the predominant PCB congeners species. PCB153 was the most abundant congener in all samples. The PCB153/SigmaPCBs consistently comprised between 20% to 30% of all congeners. The toxicity measured as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) were from 2.7 pg/g lipid weight of finless porpoise to 2,900 pg/g lipid weight of rough-toothed dolphin. PCB 118, a mono-ortho congener, was the largest contributor to TEQs. PCB concentrations and TEQs were higher in mature male than in immature male animals but were inconsistent in female animals because of a possible transferring of PCBs from maternal cetaceans to their offsprings during gestation and lactation. Stranded cetaceans had significantly higher PCB levels than by-catch cetaceans because of their higher lipid consumption during starvation or illness. From the collected samples, we also found that cetaceans from Taiwan waters had relatively lower PCB concentrations and TEQs than those from high-latitude areas.

Pharmacological evaluation of several major ingredients of Chinese herbal medicines in human hepatoma Hep3B cells

Long-dan-tan (Chinese name) is one of the most common herbal medicines used by Chinese people with chronic liver disease. Accumulated anecdotal evidence suggests that Long-dan-tan may show a beneficial effect in patients with hepatocellular carcinoma. Long-dan-tan is made from five plants: Gentiana root, Scutellaria root, Gardenia fruit, Alisma rhizome, and Bupleurum root. In this study, we have examined the cytotoxic effects of the five major ingredients isolated from the above plants, i.e. gentiopicroside, baicalein, geniposide, alisol B acetate and saikosaponin-d, respectively, on human hepatoma Hep3B cells. Annexin V immunofluorescence detection, DNA fragmentation assays and FACScan analysis of propidium iodide-staining cells showed that gentiopicroside, baicalein, and geniposide had little effect, whereas alisol B acetate and saikosaponin-d profoundly induced apoptosis in Hep3B cells. Alisol B acetate, but not saikosaponin-d, induced G2/M arrest of the cell cycle as well as a significant increase in caspase-3 activity. Interestingly, baicalein by itself induced an increase in H(2)O(2) generation and the subsequent NF-kappaB activation; furthermore, it effectively inhibited the transforming growth factor-beta(1) (TGF-beta(1))-induced caspase-3 activation and cell apoptosis. We suggest that alisol B acetate and saikosaponin-d induced cell apoptosis through the caspase-3-dependent and -independent pathways, respectively. Instead of inducing apoptosis, baicalein inhibits TGF-beta(1)-induced apoptosis via increase in cellular H(2)O(2) formation and NF-kappaB activation in human hepatoma Hep3B cells.

The cytotoxicity of jet fuel aromatic hydrocarbons and dose-related interleukin-8 release from human epidermal keratinocytes

Many jet fuel aromatic hydrocarbons are known carcinogens with the ability to both readily penetrate the skin with high absorptive flux and cause skin irritation. In order to evaluate the in vitro cutaneous toxicity of individual aromatic hydrocarbons in jet fuels and their potential for inducing skin irritation, we evaluated the LD(50), the highest non-cytotoxic (5% mortality) dose (HNTD), and interleukin-8 (IL-8) release activity of nine major jet fuel aromatic hydrocarbons in human epidermal keratinocytes (HEK). LD(50) ranged from 1.8 mM (0.03%) for cyclohexylbenzene to 82.9 mM (0.74%) for benzene, with a rank order potency of cyclohexylbenzene >trimethylbenzene >/=xylene >dimethylnaphthalene >ethylbenzene >toluene >benzene. The HNTD values ranged from 0.1 mM (0.001%) for cyclohexylbenzene to 48.2 mM (0.43%) for benzene. Naphthalene and methylnaphthalene could not be ranked in this comparison since their concentrations, presented as percentage saturation, were not comparable to the others presented as solutes in solution. There was a dose-related differential response in IL-8 release at 24 h. Toluene, xylene, trimethylbenzene, cyclohexylbenzene and dimethylnaphthalene significantly decreased IL-8 release at the respective HNTDs, while IL-8 release did not continue to decrease, or significantly increased (cyclohexylbenzene and dimethylnaphthalene), at the LD(50). IL-8 significantly increased with both doses of methylnaphthalene and naphthalene. The presence of hexadecane and mineral oil greatly attenuated the cytotoxicity elicited by individual aromatic hydrocarbons in HEK cells.

Congenital chloride diarrhea in a child

Congenital chloride diarrhea (CLD) is a rare autosomal recessive disease characterized by persistent, lifelong, watery diarrhea with high fecal chloride concentration. It results from a defect of the bicarbonate/chloride exchange system in the distal ileum and colon. Polyhydramnios, premature birth, ileus without meconium passage, hypochloremia, and hyponatremia are typical features of CLD in the neonate, followed by chronic metabolic alkalosis, hypokalemia, hypochloremia, retarded growth, and renal impairment in older children and adults if the disease is not adequately treated. The diagnosis of CLD is highly dependent on the alertness of physicians. Prompt recognition and adequate replacement of fecal loss of chloride, sodium, potassium, and water are mandatory for satisfactory disease outcome. We report a case of CLD complicated with recurrent episodes of ileus, metabolic alkalosis, and hypokalemia causing frequent hospitalization in a 4-year-old boy. Normalized electrolytes and gasometric parameters, decreased abdominal circumference, and growth catch-up were achieved after education of the parents about daily care, and provision of adequate fluid and electrolyte supplementation.

Potential application of gas chromatography/tandem mass spectrometry in the measurement of coeluting isomers

Despite the unprecedented popularity of separation chromatography, the measurement of coeluting isomeric chemicals remains an extremely difficult task. We developed an analytical scheme capable of measuring two coeluting isomers using a single chromatographic column and a gas chromatography/tandem mass spectrometry system. The protocol utilized two product ion fragments generated from a common parent ion associated with the isomers for quantitation. The utility of the analytical scheme was demonstrated with the measurements of several pairs of coeluting polychlorinated biphenyl (PCB) isomers in standard solutions and fish liver samples. Best results were given when a set of stringent constraints for the abundance ratio of the two product ion fragments was satisfied. Analyses of seven fish liver samples collected from nearshore San Diego, CA, indicated that the domain that had been previously reported to comprise PCB 153 and PCB 168 actually contained PCB 153 only. Although only a selected number of PCB congeners were examined, the results presented indicate that the analytical scheme has the potential to be used to determine the concentrations of all chromatographically coeluted isomers.

Continuous measurement of caffeine and two metabolites in blood and skeletal muscle of unrestrained adult horses by semi-automated in vivo microdialysis

Concentrations of caffeine (CA) and two metabolites were measured simultaneously in venous blood and splenius muscle of adult horses using a semi-automated in vivo microdialysis sampling technique. Dialysates from muscle and jugular vein were collected continuously for 48 h and drug levels were determined by high performance liquid chromatography (HPLC). Following i.v. injection, CA (3 mg/kg) attained a peak blood level of nearly 5400 +/- 600 ng/mL and decreased with a half-life of 15.3 +/- 0.7 h. Pharmacokinetic and statistical comparisons between CA concentrations in jugular dialysates and plasma samples revealed no significant differences between these sampling techniques. However, measurements in muscle and blood revealed unexpected pharmacokinetic differences, including significantly elevated concentrations of CA in muscle for 4 h following drug administration. In contrast, the CA metabolites theophylline (TP) and theobromine (TB) exhibited delayed appearances in muscle and blood with peak concentrations of 300 +/- 60 ng/mL (TP) and 150 +/- 50 ng/mL (TB) detected in both tissues 1 day following CA administration. This study demonstrates that our novel semi-automated microdialysis procedure for continuous monitoring of drug and metabolite levels may be useful for related studies in other domesticated large animal species.

Torsade de pointes induced by metoclopramide in an elderly woman with preexisting complete left bundle branch block

There is a growing list of drugs implicated in acquired long QT syndrome and torsade de pointes. However, the torsadogenic potential of metoclopramide, a commonly used antiemetic and prokinetic drug, has not been reported in the literature, despite its chemical similarity to procainamide. We report on a 92-year-old woman with preexisting complete left bundle branch block who developed torsade de pointes after intravenous and oral administration of metoclopramide. This patient also developed torsade de pointes when cisapride and erythromycin were given simultaneously. These two episodes were suppressed successfully after discontinuing the offending drugs and administering class IB drugs. This is the first documentation that metoclopramide provokes torsade de pointes clinically. Metoclopramide should be used cautiously in patients with a risk of torsade de pointes.