Functional improvements associated with cranioplasty after stroke and traumatic brain injury: a cohort study.

OBJECTIVE: Decompressive craniectomy is part of the acute management of several neurosurgical illnesses, and is commonly followed by cranioplasty. Data are still scarce on the functional and cognitive outcomes following cranioplasty. We aim to evaluate these outcomes in patients who underwent cranioplasty following traumatic brain injury (TBI) or stroke. METHODS: In this prospective cohort, we assessed 1-month and 6-month neuropsychological and functional outcomes in TBI and stroke patients who underwent cranioplasty at a Brazilian tertiary center. The primary outcome was the change in the Digits Test at 1 and 6 months after cranioplasty. Repeated measures general linear models were employed to assess the patients' evolution and interactions with baseline characteristics. Effect size was estimated by the partial η2. RESULTS: A total of 20 TBI and 14 stroke patients were included (mean age 42 ± 14 years; 52.9% male; average schooling 9.5 ± 3.8 years; 91.2% right-handed). We found significant improvements in the Digits Tests up to 6 months after cranioplasty (p = 0.004, partial η2 = 0.183), as well as in attention, episodic memory, verbal fluency, working memory, inhibitory control, visuoconstructive and visuospatial abilities (partial η2 0.106-0.305). We found no interaction between the cranioplasty effect and age, sex or schooling. Patients submitted to cranioplasty earlier (<1 year) after injury had better outcomes. CONCLUSION: Cognitive and functional outcomes improved after cranioplasty following decompressive craniectomy for stroke or TBI. This effect was consistent regardless of age, sex, or education level and persisted after 6 months. Some degree of spontaneous improvement might have contributed to the results.

Oculomotor, vestibular, reaction time, and cognitive tests as objective measures of neural deficits in patients post COVID-19 infection.

Objective: An alarming proportion (>30%) of patients affected by SARS-CoV-2 (COVID-19) continue to experience neurological symptoms, including headache, dizziness, smell and/or taste abnormalities, and impaired consciousness (brain fog), after recovery from the acute infection. These symptoms are self-reported and vary from patient to patient, making it difficult to accurately diagnose and initiate a proper treatment course. Objective measures to identify and quantify neural deficits underlying the symptom profiles are lacking. This study tested the hypothesis that oculomotor, vestibular, reaction time, and cognitive (OVRT-C) testing using eye-tracking can objectively identify and measure functional neural deficits post COVID-19 infection. Methods: Subjects diagnosed with COVID-19 (n = 77) were tested post-infection with a battery of 20 OVRT-C tests delivered on a portable eye-tracking device (Neurolign Dx100). Data from 14 tests were compared to previously collected normative data from subjects with similar demographics. Post-COVID subjects were also administered the Neurobehavioral Symptom Inventory (NSI) for symptom evaluation. Results: A significant percentage of post COVID-19 patients (up to 86%) scored outside the norms in 12 out of 14 tests, with smooth pursuit and optokinetic responses being most severely affected. A multivariate model constructed using stepwise logistic regression identified 6 metrics as significant indicators of post-COVID patients. The area under the receiver operating characteristic curve (AUC) was 0.89, the estimated specificity was 98% (with cutoff value of 0.5) and the sensitivity was 88%. There were moderate but significant correlations between NSI domain key variables and OVRT-C tests. Conclusions: This study demonstrates the feasibility of OVRT-C testing to provide objective measures of neural deficits in people recovering from COVID-19 infection. Such testing may serve as an efficient tool for identifying hidden neurological deficits post COVID-19, screening patients at risk of developing long COVID, and may help guide rehabilitation and treatment strategies.

Feature selection before EEG classification supports the diagnosis of Alzheimer's disease.

OBJECTIVE: In many decision support systems, some input features can be marginal or irrelevant to the diagnosis, while others can be redundant among each other. Thus, feature selection (FS) algorithms are often considered to find relevant/non-redundant features. This study aimed to evaluate the relevance of FS approaches applied to Alzheimer's Disease (AD) EEG-based diagnosis and compare the selected features with previous clinical findings. METHODS: Eight different FS algorithms were applied to EEG spectral measures from 22 AD patients and 12 healthy age-matched controls. The FS contribution was evaluated by considering the leave-one-subject-out accuracy of Support Vector Machine classifiers built in the datasets described by the selected features. RESULTS: The Filtered Subset Evaluator technique achieved the best performance improvement both on a per-patient basis (91.18% of accuracy) and on a per-epoch basis (85.29±21.62%), after removing 88.76±1.12% of the original features. All algorithms found out that alpha and beta bands are relevant features, which is in agreement with previous findings from the literature. CONCLUSION: Biologically plausible EEG datasets could achieve improved accuracies with pre-processing FS steps. SIGNIFICANCE: The results suggest that the FS and classification techniques are an attractive complementary tool in order to reveal potential biomarkers aiding the AD clinical diagnosis.

Does EEG montage influence Alzheimer's disease electroclinic diagnosis?

There is not a specific Alzheimer's disease (AD) diagnostic test. AD diagnosis relies on clinical history, neuropsychological, and laboratory tests, neuroimaging and electroencephalography. Therefore, new approaches are necessary to enable earlier and more accurate diagnosis and to measure treatment results. Quantitative EEG (qEEG) can be used as a diagnostic tool in selected cases. The aim of this study was to answer if distinct electrode montages have different sensitivity when differentiating controls from AD patients. We analyzed EEG spectral peaks (delta, theta, alpha, beta, and gamma bands), and we compared references (Biauricular, Longitudinal bipolar, Crossed bipolar, Counterpart bipolar, and Cz reference). Support Vector Machines and Logistic Regression classifiers showed Counterpart bipolar montage as the most sensitive electrode combination. Our results suggest that Counterpart bipolar montage is the best choice to study EEG spectral peaks of controls versus AD.

Gamma band oscillations in parietooccipital areas during performance of a sensorimotor integration task: a qEEG coherence study / Oscilações na banda gama em áreas parieto-occipitais durante desempenho de uma tarefa sensório-motora: um estudo de coerência na EEGq

This study aimed to elucidate cortical mechanisms involved in anticipatory actions when 23 healthy right-handed subjects had to catch a free falling object through quantitative electroencephalogram (qEEG). For this reason, we used coherence that represents a measurement of linear covariation between two signals in the frequency domain. In addition, we investigated gamma-band (30-100 Hz) activity that is related to cognitive and somatosensory processes. We hypothesized that gamma coherence will be increase in both parietal and occipital areas during moment after ball drop, due to their involvement in manipulation of objects, visuospatial processing, visual perception, stimuli identification and attention processes. We confirmed our hypothesis, an increase in gamma coherence on P3-P4 (t= -2.15; p=0.033) and PZ-OZ (t= -2.16; p=0.034) electrode pairs was verified for a paired t-test. We conclude that to execute tasks involving anticipatory movements (feedforward mechanisms), like our own task, probably, there is no need of a strong participation of visual areas in the process of information organization to manipulate objects and to process visuospatial information regarding the contact hand-object.

Este estudo teve como objetivo elucidar os mecanismos corticais envolvidos em ações antecipatórias quando 23 indivíduos saudáveis destros tinham que apreender um objeto em queda livre, através da eletroencefalografia quantitativa (EEGq). Por esta razão, usamos a coerência que representa a covariação linear entre dois sinais no domínio da frequência. Além disso, investigamos a atividade da banda gama (30-100 Hz), que está relacionada à processos cognitivos e somato-sensoriais. Nossa hipótese é que a coerência de gama estará aumentada em ambas as áreas parietais e occipitais durante o momento pós-queda da bola, devido ao seu envolvimento na manipulação de objetos, processamento visuo-espacial, percepção visual, identificação de estímulos e processos de atenção. Confirmamos nossa hipótese. Um aumento de coerência em gama nos pares de eletrodos P3-P4 (t= -2,15; p=0,033) e PZ-OZ (t= -2,16; p=0,034) foi verificado por teste-t pareado. Conclui-se que, para executar tarefas que envolvem movimentos de antecipação (mecanismos de retro-alimentação) como a nossa própria tarefa, provavelmente, não há necessidade de forte participação de áreas visuais no processo de organização da informação como para manipular objetos e processar a informação visuo-espacial no contato mão-objeto.

Incidence of dementia in a community-dwelling Brazilian population.

The authors report the incidence of dementia in a community-dwelling Brazilian population. In 1997, 1656 individuals aged 65 years or more, the majority being of very low educational level, were screened at their homes in Catanduva, Brazil, and dementia was diagnosed in 118 cases. The remaining 1538 individuals were rescreened 3.25 years later applying a health questionnaire, the Mini-Mental State Examination (MMSE) and the Pfeffer Functional Activities Questionnaire (PFAQ). According to PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratory tests and brain computed tomography. A total of 1119 individuals were rescreened and 50 incident cases of dementia (28 with Alzheimer disease [AD]) were identified. The incidence rate of dementia was 13.8 and of AD was 7.7 per 1000 person-years for individuals aged 65 years or older. The incidence rates of dementia almost doubled with every 5 years of age. There was no difference according to gender, but women had a higher incidence of dementia, predominantly AD, in very old age. There was a trend for higher incidence of dementia in illiterates (p = 0.07), but multivariate analysis disclosed significant association only between age and higher incidence of dementia. The incidence rates of dementia in this Brazilian community are comparable to those reported in Western and Asian studies.

[Alpha band coherence analysis of EEG in healthy adult's and Alzheimer's type dementia patients]. / Estudo da coerência do eletrencefalograma para a banda de frequência alfa em indivíduos adultos normais e com provável demência do tipo Alzheimer.

We studied the occipital inter-hemispheric coherence (IHCoh) of EEG (electrodes O1-O2) for alpha band (alpha1 - 8,0 to 10,0 Hz and alpha2 - 10,1 to 12,5 Hz) in healthy adults and Alzheimer's type dementia (ATD) subjects, to observe if there is any significant difference between these two groups that could help in the early diagnosis of ATD. We found a decrease of occipital IHCoh in ATD group for both alpha sub-bands. We believe that Coh analysis of EEG is a powerful auxiliary method in ATD diagnosis.

[Guidelines for recording/analyzing quantitative EEG and evoked potentials. Part II: Clinical aspects]. / Recomendações para o registro/interpretação do mapeamento topográfico do eletrencefalograma e potenciais evocados. Parte II: Correlações clínicas.

Digital EEG (DEEG) and quantitative EEG (QEEG) are recently developed tools present in many clinical situations. Besides showing didactic and research utility, they may also have a clinical role. Although a considerable amount of scientific literature has been published related to QEEG, many controversies still subsist regarding its clinical utilization. Clinical applications are: 1. DEEG is already an established substitute for conventional EEG, representing a clear technical advance. 2. Certain QEEG techniques are an established addition to DEEG for: 2a) screening for epileptic spikes or seizures in long-term recordings; 2b) Operation room and intensive care unit EEG monitoring. 3. Certain QEEG techniques are considered possible useful additions to DEEG: 3a) topographic voltage and dipole analysis in epilepsy evaluations; 3b) frequency analysis in cerebrovascular disease and dementia, mostly when other tests have been inconclusive. 4. QEEG remains investigational for clinical use in postconcussion syndrome, learning disability, attention disorders, schizophrenia, depression, alcoholism and drug abuse. EEG brain mapping and other QEEG techniques should be clinically used only by physicians highly skilled in clinical EEG interpretation and as an adjunct to traditional EEG work.

[Epilepsies with midline projected foci: study with quantitative and topographic EEG (brain mapping)]. / Epilepsias com focos projetados na linha média. Estudo com EEG quantitativo e topográfico (mapeamento cerebral).

We report a topographic and quantitative EEG (EEGQT) study of four patients with analogic EEG diagnostics of midline foci. The new study with EEGQT offered an increased definition of the electrical source with advantages in foci localization. These findings should be confirmed with studies including a greater number of patients.

[Quantitative and topographic EEG brain mapping: a study of normal adult population]. / Eletrencefalograma quantitativo e topográfico. (Mapeamento cerebral). Estudo do padrão normal para uma população adulta.

We studied the electric brain activity during wakefulness in 20 Brazilian people through digital EEG and spectral analysis in order to propose a standardization for Brazilian adult population. All this group is healthy with laboratory examinations and mini-mental state (scores higher than 27) evaluation normal. After Fourier fast transformation (FFT) calculation, we found a histogram display with monomodal distribution, with higher values in alpha band. Analyzing the average of these results, different standards from the analogical traditional EEG were found, as the distribution of alpha band and delta activity behavior. The beta 2 and beta 3 behavior showed a diffuse distribution, that is not the usual. By the other hand, other findings are congruent to the analogical EEG as the alpha posterior predominance and the bigger presence of theta activity at the central regions.

Agenesis and lipoma of corpus callosum. Case report.

The agenesis and lipoma of the corpus callosum is a very rare association. We report the case of a 18-years old woman with rare epileptic seizures since the age of 6 years, normal neurological examination, as well as normal electroencephalogram. The brain computed tomography scanning and the magnetic resonance showed the lipoma and the agenesis of the corpus callosum.

Epilepsy with continuous spike-waves during slow wave sleep: a clinical and electroencephalographic study.

We report four children with epilepsy with "continuous spike-waves during slow wave sleep" (CSWSS). The main clinical features were partial motor seizures, mental retardation and motor deficit. The EEG findings were characterized by nearly continuous (> 85%) diffuse slow spike and wave activity in two patients, and localized to one hemisphere in two other cases during non-REM sleep. The treatment was effective in improving the clinical seizures, but not the EEG pattern. We believe that this epileptic syndrome has been overlooked and routine sleep EEG studies on epileptic children may disclose more cases of CSWSS.

Atypical EEG pattern in children with absence seizures.

We studied four children with diagnosis of absence seizures (generalized primary epilepsy), and with a generalized delta activity on the EEG during clinical attacks provoked by hyperventilation. The lack of ictal generalized spike-and-wave discharges with a frequency of 3 Hz in our patients, makes this an atypical pattern. All children had complete control of their seizures and disappearance of the EEG changes with valproate. We concluded that generalized delta activity observed on EEG during the hyperventilation in children should not always be considered as a normal finding for age, since it could be an ictal event of an absence seizure.

Atypical pattern related to 14 Hz positive spikes.

We studied two children with a history of headache and a normal physical and neurological examination whose EEG showed an electroencephalographic pattern recently published, the N-shape potential associated with the 14 Hz positive spikes. This graphoelement was observed only during the asleep state.

Dipole reversal: an ictal feature in a patient with benign partial epilepsy of childhood with centro-temporal spike.

We describe the case of a 15-year-old boy who had the diagnosis of benign partial epilepsy of childhood with centro-temporal spike. During the EEG a subclinical electrographic seizure was recorded. The discharges were clearly electropositive in T4 with positive phase reversal between derivations F8-T4 and T4-T6. The whole episode lasted less than one minute (45 sec). The interictal right medio-temporal spikes reemerged after 60 sec and were electronegative in the same location after the end of the electrographic seizures. The mechanisms underlying this uncommon pattern on EEG is not well established.

Subclinical rhythmic electrographic discharge in adults: an atypical evolution.

The subclinical rhythmic electrographic discharge in adults (SREDA) has been rarely reported. We describe the case of a 71 year-old man with transient ischemic attack, whose EEG showed an atypical evolution of this uncommon pattern. The computed tomography scan and cerebrospinal fluid were normal. We are not aware of any other report in the literature with this atypical evolution of SREDA.

Complex partial status epilepticus in a child.

Complex partial status epilepticus (SE) has been reported rarely in children. We describe the clinical case of a 14 year-old girl with complex partial seizures (CPS) since age 10 who developed a complex partial SE probably because she was not adherent to treatment. The neurologic examination and computed tomography scan were normal. During the SE she received diazepam and phenytoin and became free of the seizures after 5 minutes. The ictal EEG showed spikes and slow waves over the right temporal region.

Atypical clinical and electroencephalographic pattern in a patient with subacute sclerosing panencephalitis.

We describe an atypical clinical and electroencephalographic (EEG) pattern observed during the course of subacute sclerosing panencephalitis in a 14 year-old boy. In this patient with a two weeks history of partial complex seizures, the atypical EEG pattern was characterized by an initial left temporal focus which evolved to periodic lateralized epileptiform discharges (PLEDs) and, only during the 3rd and 4th weeks the typical bilateral and generalized periodic complexes appeared.