Non-invasive Brain Stimulation Can Reduce Unilateral Spatial Neglect after Stroke: ELETRON Trial.

OBJECTIVE: Rehabilitation top-down techniques based on brain stimulation present variable outcomes in unilateral spatial neglect (USN) after stroke. This study aimed to examine the effects of physical therapy after anodal and cathodal transcranial direct current stimulation (A-tDCS and C-tDCS, respectively) to improve visuospatial and functional impairments in individuals with USN after stroke. METHODS: This double-blinded, pilot randomized clinical trial enrolled patients with USN after ischemic stroke. Randomization was stratified according to the Behavior Inattention Test-Conventional (BIT-C) and Catherine Bergego Scale (CBS). Outpatient physical therapy was conducted for 7.5 weeks after 20 minutes of tDCS. The primary outcome was the USN degree evaluated by the BIT-C. Secondary outcomes were the difference in CBS score, stroke severity (National Institutes of Health Stroke Scale [NIHSS]), disability (modified Rankin Scale), autonomy (Barthel Index, Functional Independence Measure), and quality of life (EuroQol Group 5-Dimension Self-Report Questionnaire). Outcomes were analyzed using an analysis of covariance model corrected by age, baseline NIHSS, and baseline BIT-C. Pairwise post hoc comparisons were performed using Bonferroni correction. RESULTS: In the primary outcomes, A-tDCS led to greater improvement in BIT-C after intervention (mean difference [MD] = 18.4, 95% confidence interval [CI] = 3.9-32.8, p = 0.008) compared to sham. However, no significant differences were observed between A-tDCS and C-tDCS (MD = 13.9, 95% CI = -0.3 to 28.1, p = 0.057), or C-tDCS and sham (MD = 4.5, 95% CI = -9.7 to 18.8, p = 0.99). There were no significant differences between groups in terms of secondary outcomes. INTERPRETATION: A-tDCS associated with physical therapy can decrease the severity of USN after stroke. However, these preliminary findings must be confirmed by collecting additional evidence in a larger phase 3 trial. ANN NEUROL 2022;92:400-410.

Source Analysis of Triphasic Waves Using Quantitative Neuroimaging.

PURPOSE: Triphasic waves (TWs), a common EEG pattern, are considered a subtype of generalized periodic discharges. Most patients with TWs present with an altered level of consciousness, and the TW pattern is believed to represent thalamocortical dysfunction. However, the exact meaning and mechanism of TWs remain unclear. The objective of the current study was to evaluate the source of TWs using EEG source imaging and computerized tomography. METHODS: Twenty-eight patients with TWs were investigated. Source analysis was performed on the averaged TWs for each individual, and source maps were extracted. Normalization and automatic segmentation of gray matter were performed on computerized tomography scans before analysis. Finally, voxelwise correlation analyses were conducted between EEG source maps and gray matter volumes. RESULTS: Source analyses showed that the anterior cingulate cortex was mainly involved in TWs (16/28 patients, 57%). Correlation analyses showed moderate positive and negative correlations between source location and gray matter volumes for the posterior cingulate ( T = 2.85; volume = 6,533 mm 3 ; r = 0.53; P = 0.002) and the superior frontal gyrus ( T = 2.54; volume = 18,167 mm 3 ; r = -0.48; P < 0.0001), respectively. CONCLUSIONS: The results suggest that the anterior cingulate is involved in the origin of TWs. Furthermore, the volumes of posterior brain regions were positively correlated with TWs, indicating a possible preservation of these structures. Conversely, the volumes of anterior regions were negatively correlated with TWs. These findings may indicate a structural pattern necessary for the generation of the abnormal network responsible for TWs.

What are the barriers to participation in a neuromodulation pilot trial for aphasia after stroke?

PURPOSE: Aphasia is a common and debilitating manifestation of stroke. Transcranial electrical stimulation uses low-intensity electric currents to induce changes in neuronal activity. Recent evidence suggests that noninvasive techniques can be a valuable rehabilitation tool for patients with aphasia. However, it is difficult to recruit patients with aphasia for trials, and the reasons for this are not well understood. This study aimed to elucidate the main difficulties involved in patient's recruitment and inclusion in a randomized clinical study of neuromodulation in aphasia. METHODS: We evaluated the reasons for the exclusion of patients in a pilot, randomized, double-blinded clinical trial in which patients diagnosed with motor aphasia after stroke were recruited from March to November 2018. A descriptive statistical analysis was performed. RESULTS: Only 12.9% (4) of patients with ischemic stroke were included in the clinical trial. A total of 87.1% (27) of the 31 recruited patients were excluded for various reasons including: sensory aphasia (32.2%), dysarthria (25.8%), spontaneous clinical recovery (16.1%), previous stroke (6.4%), and death or mutism (3.2%). CONCLUSION: The presence of other types of aphasia, dysarthria, spontaneous recovery, deaths, and mutism were barriers to recruiting patients evidenced in this neuromodulation study.

Analysis of Interictal Epileptiform Discharges in Mesial Temporal Lobe Epilepsy Using Quantitative EEG and Neuroimaging.

Objective: Investigate areas of correlation between gray matter volumes by MRI and interictal EEG source maps in subtypes of mesial temporal lobe epilepsy (MTLE). Method: 71 patients and 36 controls underwent 3T MRI and and routine EEG was performed. Voxel-based morphometry (VBM) was used for gray matter analysis and analysis of interictal discharge sources for quantitative EEG. Voxel-wise correlation analysis was conducted between the gray matter and EEG source maps in MTLE subtypes. Results: The claustrum was the main structure involved in the individual source analysis. Twelve patients had bilateral HA, VBM showed bilateral hippocampal. Twenty-one patients had right HA, VBM showed right hippocampal and thalamic atrophy and negatively correlated involving the right inferior frontal gyrus and insula. Twenty-two patients had left HA, VBM showed left hippocampal atrophy and negatively correlated involving the left temporal lobe and insula. Sixteen patients had MTLE without HA, VBM showed middle cingulate gyrus atrophy and were negatively correlated involving extra-temporal regions, the main one located in postcentral gyrus. Conclusions: Negative correlations between gray matter volumes and EEG source imaging. Neuroanatomical generators of interictal discharges are heterogeneous and vary according to MTLE subtype. Significance: These findings suggest different pathophysiological mechanisms among patients with different subtypes of MTLE.

Quantile graphs for EEG-based diagnosis of Alzheimer's disease.

Known as a degenerative and progressive dementia, Alzheimer's disease (AD) affects about 25 million elderly people around the world. This illness results in a decrease in the productivity of people and places limits on their daily lives. Electroencephalography (EEG), in which the electrical brain activity is recorded in the form of time series and analyzed using signal processing techniques, is a well-known neurophysiological AD biomarker. EEG is noninvasive, low-cost, has a high temporal resolution, and provides valuable information about brain dynamics in AD. Here, we present an original approach based on the use of quantile graphs (QGs) for classifying EEG data. QGs map frequency, amplitude, and correlation characteristics of a time series (such as the EEG data of an AD patient) into the topological features of a network. The five topological network metrics used here-clustering coefficient, mean jump length, betweenness centrality, modularity, and Laplacian Estrada index-showed that the QG model can distinguish healthy subjects from AD patients, with open or closed eyes. The QG method also indicates which channels (corresponding to 19 different locations on the patients' scalp) provide the best discriminating power. Furthermore, the joint analysis of delta, theta, alpha, and beta wave results indicate that all AD patients under study display clear symptoms of the disease and may have it in its late stage, a diagnosis known a priori and supported by our study. Results presented here attest to the usefulness of the QG method in analyzing complex, nonlinear signals such as those generated from AD patients by EEGs.

Volumetric MRI Changes in Spinocerebellar Ataxia (SCA3 and SCA10) Patients.

Spinocerebellar ataxias type 3 (SCA3) and type 10 (SCA10) are the most prevalent in southern Brazil. To analyze the relationships between volumetric MRI changes and clinical and genetic findings in SCA3 and SCA10 patients. All patients in the study had a confirmed genetic diagnosis. Demographic data, ataxia severity (SARA score), and the size of the expanded alleles were evaluated. Nineteen SCA3 and 18 SCA10 patients were selected and compared with a similar number of healthy controls. Patient and control groups underwent the same MRI protocol. The standard FreeSurfer pipeline was used for the morphometric data. Our results show more affected brain structures (volume reductions) in SCA3 patients than in SCA10 patients (15 vs. 5 structures). Volume reductions in brain structures were also greater in the former. The main areas with significant volumetric reductions in the former were the cerebellum, basal ganglia, brain stem, and diencephalon, whereas in the latter, significant volume reductions were observed in the cerebellum and pallidum. While SARA scores and disease duration were more correlated with volume reduction in SCA10, in SCA3, the expansion length (CAGn) correlated positively with cerebellar WM, thalamus, brain stem, and total GM volumes. There was no correlation between expansion length (ATTCTn) and neuroimaging findings in SCA10. Neuroimaging results differed significantly between SCA3 and SCA10 patients and were compatible with the differences in clinical presentation, disease progression, and molecular findings.

Analysis of patients with obstructive sleep apnea with and without pharyngeal myopathy using brain neuroimaging.

STUDY OBJECTIVES: Elements impairing upper airway anatomy or muscle function (e.g. pharyngeal neuromyopathy) contribute to obstructive sleep apnea syndrome (OSAS). Structural brain imaging may differ in patients with OSAS according to dilator muscle dysfunction. Magnetic resonance imaging (MRI) with voxel-based morphometry (VBM) and surface-based morphometry (SBM) was used to investigate this hypothesis. METHODS: Eighteen patients with OSAS and 32 controls underwent 3T brain MRI. T1 volumetric images were used for structural analysis. Pharyngeal electroneuromyography was performed; patients with OSAS were classified as with or without neuromyopathy. VBM and SBM analyses were conducted using SPM12 and CAT12 software. Image processing was standard. Cortical surface parameters and gray and white matter volumes from participants with OSAS with and without neuromyopathy were compared with those from controls. RESULTS: Eleven patients had OSAS with neuromyopathy and seven patients had OSAS without neuromyopathy (normal pharyngeal electroneuromyography). Comparing these groups to the controls, VBM revealed: four clusters (total volume 15,368 mm3) for patients with neuromyopathy, the largest cluster in the left cerebellum (9,263 mm3, p = 0.0001), and three clusters (total 8,971 mm3) for patients without neuromyopathy, the largest cluster in the left cerebellum (5,017 mm3, p = 0.002). Patients with OSAS with neuromyopathy showed increased proportion of atrophy (p < 0.0001). SBM showed abnormalities in patients without neuromyopathy (decreased cortical thickness, left precentral gyrus [672 vertices, p = 0.04]; increased cortical complexity, right middle temporal gyrus [578 vertices, p = 0.032]). CONCLUSION: Damaged areas were larger in patients with OSAS with than in those without neuromyopathy, suggesting differences in brain involvement. Patients with OSAS and neuromyopathy may be more susceptible to cerebral damage.

Anxiety and depression symptoms disrupt resting state connectivity in patients with genetic generalized epilepsies.

OBJECTIVE: To analyze the lifetime trajectories in genetic generalized epilepsies (GGEs) and investigate the impact of symptoms of anxiety and depression on resting state functional connectivity (FC). METHODS: Seventy-four GGE patients were classified according to the pharmacological response as seizure-free (12 patients), pharmacoresistant (PhR; 14 patients), and fluctuating (FL; 48 patients). Fifty-four subjects completed both the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI), and 38 also underwent 3-T resting state functional magnetic resonance imaging. These 38 patients were subdivided into a positive group (13 patients with concurrent symptoms of depression and anxiety) and a negative group (21 asymptomatic patients and four with mild anxiety or depression symptoms). For FC analysis of resting state networks, we matched 38 healthy asymptomatic volunteers and used the UF2C toolbox running on MATLAB2017/SPM12. RESULTS: The PhR group presented shorter duration of epilepsy (P = 0.016) and follow-up (P < 0.001) compared to the FL group. The PhR group showed higher levels (median = 20) on the BAI and BDI. Myoclonic seizures were the most difficult to control, as 50% of subjects persisted with them at last appointment, compared to generalized tonic-clonic seizures and absence seizures (<40%). Patients with concurrent anxiety and depression symptoms were 7.7 times more likely to exhibit pharmacoresistant seizures, although an increase of 1 year of epilepsy duration was associated with a decrease in the odds of presenting pharmacoresistance by a factor of 0.9. Overall, FC was altered between default mode network (DMN) and visuospatial/dorsal attention. However, only the positive group displayed abnormal FC between DMN and left executive control network, and between salience and visuospatial/dorsal attention. SIGNIFICANCE: Our findings may help clinicians to have a better understanding of GGE clinical course and increase attention to the potential relationship of psychopathologies and brain connectivity.

Effects of virtual reality therapy on upper limb function after stroke and the role of neuroimaging as a predictor of a better response.

OBJECTIVE: Virtual reality therapy (VRT) is an interactive intervention that induces neuroplasticity. The aim was to evaluate the effects of VRT associated with conventional rehabilitation for an upper limb after stroke, and the neuroimaging predictors of a better response to VRT. METHODS: Patients with stroke were selected, and clinical neurological, upper limb function, and quality of life were evaluated. Statistical analysis was performed using a linear model comparing pre- and post-VRT. Lesions were segmented in the post-stroke computed tomography. A voxel-based lesion-symptom mapping approach was used to investigate the relationship between the lesion and upper limb function. RESULTS: Eighteen patients were studied (55.5 ± 13.9 years of age). Quality of life, functional independence, and dexterity of the upper limb showed improvement after VRT (p < 0.001). Neuroimaging analysis showed negative correlations between the internal capsule lesion and functional recovery. CONCLUSION: VRT showed benefits for patients with stroke, but when there was an internal capsule lesion, a worse response was observed.

Effects of virtual reality therapy on upper limb function after stroke and the role of neuroimaging as a predictor of a better response / Efeitos da terapia de realidade virtual na função do membro superior após AVC e o papel da neuroimagem como preditor de melhor resposta

ABSTRACT Background: Virtual reality therapy (VRT) is an interactive intervention that induces neuroplasticity. The aim was to evaluate the effects of VRT associated with conventional rehabilitation for an upper limb after stroke, and the neuroimaging predictors of a better response to VRT. Methods: Patients with stroke were selected, and clinical neurological, upper limb function, and quality of life were evaluated. Statistical analysis was performed using a linear model comparing pre- and post-VRT. Lesions were segmented in the post-stroke computed tomography. A voxel-based lesion-symptom mapping approach was used to investigate the relationship between the lesion and upper limb function. Results: Eighteen patients were studied (55.5 ± 13.9 years of age). Quality of life, functional independence, and dexterity of the upper limb showed improvement after VRT (p < 0.001). Neuroimaging analysis showed negative correlations between the internal capsule lesion and functional recovery. Conclusion: VRT showed benefits for patients with stroke, but when there was an internal capsule lesion, a worse response was observed.

RESUMO Introdução: A realidade virtual (RV) é uma intervenção interativa que induz a neuroplasticidade. O objetivo deste estudo foi avaliar os efeitos da RV associado à reabilitação convencional na função do membro superior após o AVC e as características preditores de neuroimagem de melhor resposta a esta terapia. Métodos: os pacientes com AVC foram selecionados, e as características neurológicas, a função do membro superior e a qualidade de vida foram avaliadas. A análise estatística foi realizada por meio de modelo linear geral comparando resultados pré e pós-intervenção. As lesões foram segmentadas na tomografia computadorizada após o AVC. A abordagem de mapeamento da lesão-sintoma baseada em voxel foi utilizada para avaliar a relação entre a lesão e a função do membro superior. Resultados: Foram estudados 18 pacientes (8 mulheres, 55,5 ± 13,9 anos). A qualidade de vida, independência funcional, características funcionais e destreza do membro superior apresentaram melhora após RV (p < 0,001). A análise de imagem mostrou correlações negativas principalmente entre a cápsula interna e a recuperação funcional do membro superior. Conclusão: A RV mostrou benefícios para pacientes com AVC, mas quando houve lesão da cápsula interna apresentaram pior resposta à terapia.

Which of the branched-chain amino acids increases cerebral blood flow in hepatic encephalopathy? A double-blind randomized trial.

Branched-chain amino acids increase the brain perfusion of patients with hepatic encephalopathy (HE), but the amino acid and the mechanisms involved are still unknown. This study compared brain perfusion and clinical improvement during leucine or isoleucine supplementation. After randomization, 27 subjects with cirrhosis and HE received leucine or isoleucine supplements for one year. Brain single Photon Emission Computed Tomography (SPECT) and dynamic brain scintigraphy (DBS) were performed pretreatment and at 1, 8 and 12 months of supplementation. Brain perfusion was increased only in the isoleucine group at 8 months of treatment by both SPECT and DBS (p < 0.001 and p = 0.05, respectively) and by SPECT at the 12th month (p < 0.05). This was associated with hepatic encephalopathy improvement at 8 and 12 months (p = 0.008 and 0.004, respectively), which was not observed in the leucine group (p = 0.313 and 0.055, respectively). Isoleucine supplementation achieved a better impact on brain perfusion restoration in HE.

Crossed Leg Sign Is Associated With Severity of Unilateral Spatial Neglect After Stroke.

BACKGROUND: The crossed leg sign in patients with right hemisphere stroke is thought to be associated with perceptual disorders, such as unilateral spatial neglect (USN). The aim of this study was to compare the crossed leg sign with the severity of USN during the acute phase of stroke. EXPERIMENTAL PROCEDURES: This was an observational and prospective clinical study of individuals with a diagnosis of right parietal stroke, as confirmed by neuroimaging. The occurrence of the crossed leg sign, the time at which this occurred after the stroke, and a clinical diagnosis of USN were measured and recorded. The patients' age, sex, and lesion severity, as determined by the National Institutes of Health Stroke Scale and Glasgow coma scale, were included in the analyses as confounding variables. The outcome of interest was the degree of USN, as measured by the cancellation and bisection tests. Binary logistic regression was used to analyze the effect of crossed leg syndrome on the severity of USN. In the adjusted multiple regression model, a p-value of <0.05 was considered statistically significant. RESULTS: Overall, 60 patients were included in this study. There were no associations between patient demographics and the presence of the crossed leg sign. There was, however, an association between the crossed leg sign and the absolute value of the deviation in the line bisection test (B = -0.234; p = 0.039). The crossed leg sign was not associated with other measures of USN. CONCLUSION: Based on the results of our study, we can conclude that a crossed leg sign in the acute phase of stroke is associated with USN severity, specifically the misinterpretation of the midline.

Voxel-based analysis of diffusion tensor imaging in patients with mesial temporal lobe epilepsy.

PURPOSE: Quantitative techniques of diffusion analysis allow for an in-vivo investigation of the physiopathology of epilepsies. The objective of this study was to evaluate the variation of the main diffusion parameters and explore differences between two methodologies of voxel-wise analysis comparing a group of patients with mesial temporal lobe epilepsy (MTLE) with controls. METHODS: 24 patients with a diagnosis of MTLE were selected. All patients and a control group of 36 individuals were submitted to 3T magnetic resonance imaging. Diffusion parameters were obtained from the raw images. Based on the tensors, a customized template was created, and images were registered into standard space. Voxel-based comparisons between patients and controls was performed by whole brain voxel-wise analysis and tract-based spatial statistics (TBSS). Tract-specific analysis (TSA) was performed in the mostly damaged fasciculi. RESULTS: 10 patients presented with right hippocampal sclerosis (HS), 11 with left HS and 3 with bilateral HS with left predominance. Whole brain voxel-wise analysis showed abnormalities mainly localized in the temporal lobes (total volume of 3859mm3). TBSS showed more widespread abnormalities (21931mm3). TSA pointed to abnormalities situated essentially in the temporal stem topography. Fractional anisotropy (FA) and radial diffusivity (RD) were the parameters that showed more abnormalities. CONCLUSION: Whole brain voxel-wise analysis was more restricted than TBSS. The methods were complementary stressing the significance of the findings. The abnormalities were more frequently observed in FA and RD indicating the need for using several diffusion parameters for the investigation of patients with MTLE.

Hippocampal Damage and Atrophy Secondary to Status Epilepticus in a Patient with Schizophrenia.

A 59-year-old man was admitted with respiratory tract infection, compromised conscience and generalized tonic-clonic seizures. His medical history included schizophrenia diagnosis, for which he had been being treated since he was 27 years old. EEG disclosed non-convulsive status epilepticus. A magnetic resonance image (MRI) acquired 3 days later showed increased left hippocampal volume with hyperintensity on T2-weighted and FLAIR sequences. After being treated with antibiotics and antiepileptic medications, the patient's condition improved. A follow-up MRI showed reduction of the left hippocampus. The relationship between epilepsy and schizophrenia is not yet clear. This case illustrates this interaction. Hippocampal atrophy may have been caused by environmental aggression in the present patient with schizophrenia, perhaps in association with a predisposing genotype.

Critical analysis of diagnostic criteria (ICHD-3 beta) about migraine in childhood and adolescence / Análise crítica dos critérios diagnósticos (CIC-3 beta) de enxaqueca em crianças e adolescentes

Objective The objective of this study was to prospectively evaluate the International Classification of Headache Disorders I (ICHD-I) diagnostic criteria for migraine in children and adolescents. Methods 150 pain diaries were analyzed during an initial consultation. The duration of migraine headache attacks were divided into 2 groups: Group I, for attacks lasting > 2 hours, and Group II, for attacks lasting < 2 hours.The two groups were statistically compared using Fisher’s exact test (p < 0.05). Results In this study, 51(34%) subjects were male and 99 (66%) were female, aged 7–15 years. Fisher’s exact test demonstrated that the ICHD-3 beta had a 58% sensitivity for Group I diagnoses and a 94% sensitivity for Group II diagnoses (p < 0.001). Conclusion The current ICHD-3 beta classification improves and advances migraine diagnosis in children and adolescents; however, more research is needed to identify additional characteristics of headache in this age group.

Objetivo O objetivo deste estudo foi avaliar prospectivamente os critérios diagnósticos da Classificação Internacional das Cefaleias 3 beta (CIC-3) de enxaqueca em crianças e adolescentes. Métodos 150 diários de dor foram analisados durante a consulta inicial. A duração dos episódios de enxaqueca foram divididos em dois grupos: Grupo I, para episódios com duração > 2 horas, e Grupo II, para os episódios < 2 horas. Os dois grupos foram comparados estatisticamente pelo teste exato de Fisher (p < 0,05). Resultados Neste estudo, 51 (34%) pacientes eram do sexo masculino e 99 (66%) eram do sexo feminino, com idade entre 7-15 anos. O teste exato de Fisher demonstrou que a CIC-3 beta teve sensibilidade de 58% para o diagnóstico do Grupo I e 94% para o diagnóstico do Grupo II (p < 0,001). Conclusão A atual classificação CIC-3 beta melhora e avança diagnóstico de enxaqueca em crianças e adolescentes; no entanto, mais pesquisas são necessárias para identificar as características adicionais de cefaléia nessa faixa etária.

Critical analysis of diagnostic criteria (ICHD-3 beta) about migraine in childhood and adolescence.

OBJECTIVE: The objective of this study was to prospectively evaluate the International Classification of Headache Disorders I (ICHD-I) diagnostic criteria for migraine in children and adolescents. METHODS: 150 pain diaries were analyzed during an initial consultation. The duration of migraine headache attacks were divided into 2 groups: Group I, for attacks lasting > 2 hours, and Group II, for attacks lasting < 2 hours.The two groups were statistically compared using Fisher's exact test (p < 0.05). RESULTS: In this study, 51(34%) subjects were male and 99 (66%) were female, aged 7-15 years. Fisher's exact test demonstrated that the ICHD-3 beta had a 58% sensitivity for Group I diagnoses and a 94% sensitivity for Group II diagnoses (p < 0.001). CONCLUSION: The current ICHD-3 beta classification improves and advances migraine diagnosis in children and adolescents; however, more research is needed to identify additional characteristics of headache in this age group.

Analysis of generalized interictal discharges using quantitative EEG.

Experimental evidence from animal models of the absence seizures suggests a focal source for the initiation of generalized spike-and-wave (GSW) discharges. Furthermore, clinical studies indicate that patients diagnosed with idiopathic generalized epilepsy (IGE) exhibit focal electroencephalographic abnormalities, which involve the thalamo-cortical circuitry. This circuitry is a key network that has been implicated in the initiation of generalized discharges, and may contribute to the pathophysiology of GSW discharges. Quantitative electroencephalogram (qEEG) analysis may be able to detect abnormalities associated with the initiation of GSW discharges. The objective of this study was to determine whether interictal GSW discharges exhibit focal characteristics using qEEG analysis. In this study, 75 EEG recordings from 64 patients were analyzed. All EEG recordings analyzed contained at least one GSW discharge. EEG recordings were obtained by a 22-channel recorder with electrodes positioned according to the international 10-20 system of electrode placement. EEG activity was recorded for 20 min including photic stimulation and hyperventilation. The EEG recordings were visually inspected, and the first unequivocally confirmed generalized spike was marked for each discharge. Three methods of source imaging analysis were applied: dipole source imaging (DSI), classical LORETA analysis recursively applied (CLARA), and equivalent dipole of independent components with cluster analysis. A total of 753 GSW discharges were identified and spatiotemporally analyzed. Source evaluation analysis using all three techniques revealed that the frontal lobe was the principal source of GSW discharges (70%), followed by the parietal and occipital lobes (14%), and the basal ganglia (12%). The main anatomical sources of GSW discharges were the anterior cingulate cortex (36%) and the medial frontal gyrus (23%). Source analysis did not reveal a common focal source of GSW discharges. However, there was a predominance of GSW discharges originating from the cingulate gyrus and the frontal lobe.

Quantitative EEG evaluation in patients with acute encephalopathy.

OBJECTIVE: To investigate the use of quantitative EEG (qEEG) in patients with acute encephalopathies (AEs) and EEG background abnormalities. METHOD: Patients were divided into favorable outcome (group A, 43 patients) and an unfavorable outcome (group B, 5 patients). EEGLAB software was used for the qEEG analysis. A graphic of the spectral power from all channels was generated for each participant. Statistical comparisons between the groups were performed. RESULTS: In group A, spectral analysis revealed spectral peaks (theta and alpha frequency bands) in 84% (38/45) of the patients. In group B, a spectral peak in the delta frequency range was detected in one patient. The remainder of the patients in both groups did not present spectral peaks. Statistical analysis showed lower frequencies recorded from the posterior electrodes in group B patients. CONCLUSION: qEEG may be useful in the evaluations of patients with AEs by assisting with the prognostic determination.