Implicaciones de iniciar fármacos antiepilépticos previo a la realización de EEG en primeras crisis epilépticas / Implications of initiating antiseizure drugs prior to the performance of EEG in first epileptic seizures

Introducción: Determinar si la administración de fármacos antiepilépticos (FAE) puede alterar la probabilidad de encontrar anomalías epileptiformes en EEG realizados de forma precoz tras una primera crisis epiléptica (CE). Método: Estudio observacional retrospectivo en el que se incluyó a los pacientes atendidos en urgencias de nuestro centro por una primera CE entre julio del 2014 y noviembre del 2019. Se recogieron los datos clínicos, las características técnicas de adquisición e interpretación de los EEG efectuados durante las primeras 72 h tras la CE y los factores relacionados con la recurrencia. Resultados: Se recogieron 155 pacientes; edad media 48,6 ±22,5 años; 61,3% hombres. El 51% presentó crisis tónico-clónicas de inicio desconocido y el 12% focales con progresión a tónico-clónica bilateral. El 25,2% (39/155) recibió tratamiento con FAE antes de la realización del EEG; en 33 pacientes se administró un FAE no benzodiacepínico y en 6 una benzodiacepina. Se observaron anomalías epileptiformes en 29,7% de los pacientes. La administración previa de FAE no se asoció de forma significativa ni con la probabilidad de detectar anomalías epileptiformes (p = 0,25) ni con el riesgo de recurrencia a los 6 meses (p = 0,63). Conclusiones: La administración de un FAE previo a la realización del EEG precoz tras una primera CE no disminuye la probabilidad de detectar anomalías epileptiformes. Estos hallazgos sugieren que iniciar un FAE de forma inmediata en aquellos pacientes con alto riesgo de recurrencia precoz no implica un menor rendimiento diagnóstico de dicha prueba.(AU)

Introduction: This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure. Method: We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72 hours after the seizure, and the factors related with seizure recurrence. Results: We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P=.25) or with the risk of recurrence within 6 months (P=.63). Conclusions: Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.(AU)

Marcadores Neurales como Indicadores de Funciones Predictivas en Pacientes con Traumatismo Cerebral Moderado a Severo / Neural Markers as Indicators of Predictive Functions in Patients with Moderate to Severe Brain Trauma

Introducción. El traumatismo encéfalo craneano moderado a severo (TEC-MS) es una condición compleja que cambia la estructura y función del cerebro, afectando a personas de distintas edades. Los problemas cognitivos y motores son la mayor causa de discapacidad en individuos con TEC-MS crónico. Sin embargo, muchas de estas dificultades no son visibles de inmediato clasificándose como una "Epidemia silenciosa". Las principales alteraciones reportadas por los pacientes tienen relación con problemas de la memoria, atención y lentitud psicomotora, los cuales tienen un impacto en su independencia y funcionalidad. Objetivo. Este estudio tiene por objetivo discutir y revisar la evidencia disponible acerca de la capacidad de los pacientes crónicos con TEC-MS para generar predicciones en diferentes niveles de procesamiento cerebral. Métodos. Para esto, utilizamos desde las neurociencias el modelo teórico del código predictivo para explicar las respuestas neurofisiológicas adquiridas bajo un paradigma de predicción auditiva. Esta información es complementada con el reporte de datos preliminares de sujetos con TEC-MS y sujetos control, con el fin de ilustrar los aspectos teóricos discutidos. Conclusiones. Esto podría contribuir a una mejor comprensión de los mecanismos neurales detrás de los déficits cognitivos en esta población, aportando una perspectiva que nos oriente al desarrollo de nuestras estrategias terapéuticas.

Background. Moderate to severe traumatic brain injury (TBI-MS) is a complex condition that changes the structure and function of the brain, affecting people of different ages. Cognitive and motor problems are the major cause of disability in individuals with chronic ECT-MS. However, many of these difficulties are not immediately visible, classifying them as a "Silent Epidemic." The main alterations reported by patients are related to problems with memory, attention and psychomotor slowness, which have an impact on their independence and functionality. Objetive. This study aims to discuss and review the available evidence about the ability of chronic ECT-MS patients to generate predictions at different levels of brain processing. Methods. For this, we use the theoretical model of the predictive code from neuroscience to explain the neurophysiological responses acquired under an auditory prediction paradigm. This information is complemented with the report of preliminary data from subjects with ECT-MS and control subjects, in order to illustrate the theoretical aspects discussed. Conclusions. This could contribute to a better understanding of the neural mechanisms behind cognitive deficits in this population, providing a perspective that guides us in the development of our therapeutic strategies.

Posttraumatic growth EEG neuromarkers: translational neural comparisons with resilience and PTSD in trauma-exposed healthy adults.

Background: Supporting wellbeing beyond symptom reduction is necessary in trauma care. Research suggests increased posttraumatic growth (PTG) may promote wellbeing more effectively than posttraumatic stress disorder (PTSD) symptom reduction alone. Understanding neurobiological mechanisms of PTG would support PTG intervention development. However, most PTG research to-date has been cross-sectional data self-reported through surveys or interviews.Objective: Neural evidence of PTG and its coexistence with resilience and PTSD is limited. To advance neural PTG literature and contribute translational neuroscientific knowledge necessary to develop future objectively measurable neural-based PTG interventions.Method: Alpha frequency EEG and validated psychological inventories measuring PTG, resilience, and PTSD symptoms were collected from 30 trauma-exposed healthy adults amidst the COVID-19 pandemic. EEG data were collected using custom MNE-Python software, and a wireless OpenBCI 16-channel dry electrode EEG headset. Psychological inventory scores were analysed in SPSS Statistics and used to categorise the EEG data. Power spectral density analyses, t-tests and ANOVAs were conducted within EEGLab to identify brain activity differentiating high and low PTG, resilience, and PTSD symptoms.Results: Higher PTG was significantly differentiated from low PTG by higher alpha power in the left centro-temporal brain area around EEG electrode C3. A trend differentiating high PTG from PTSD was also indicated in this same location. Whole-scalp spectral topographies revealed alpha power EEG correlates of PTG, resilience and PTSD symptoms shared limited, but potentially meaningful similarities.Conclusion: This research provides the first comparative neural topographies of PTG, resilience and PTSD symptoms in the known literature. Results provide objective neural evidence supporting existing theory depicting PTG, resilience and PTSD as independent, yet co-occurring constructs. PTG neuromarker alpha C3 significantly delineated high from low PTG and warrants further investigation for potential clinical application. Findings provide foundation for future neural-based interventions and research for enhancing PTG in trauma-exposed individuals.

Objective translational study designed to increase neural understanding of posttraumatic growth (PTG) and provide a basis for future neural-based interventions to enhance PTG.Results provide neural evidence of PTG as an independent construct that coexists, and shares limited neural relatedness with resilience and PTSD symptoms.Increased PTG was significantly related to higher alpha power in the left centro-temporal brain area around EEG electrode C3: This finding warrants further investigation for potential clinical application.

[Subtle and subclinical neurological findings in patients with SARS-CoV-2]. / Hallazgos sutiles y subclínicos neurológicos en pacientes con SARS-CoV-2.

Background: There are severe neurological conditions in patients with COVID-19, such as: cerebrovascular disease, Guillain-Barré syndrome, encephalitis, acute hemorrhagic necrotizing encephalopathy and myelitis. Objective: We describe that the patient with SARS-CoV 2 with respiratory symptoms has subtle or subclinical neurological manifestations. Material and methods: Observational, cross-sectional, analytical study, which included patients aged 18-65 years with respiratory symptoms and a confirmed diagnosis of COVID-19. Intubated patients with chronic neurodegenerative diseases or pre-existing neurological compromise were excluded. Semiology of the headache and neurological examination were performed; Serum levels of glucose, protein, electrolytes, lactate, C-reactive protein, lactic dehydrogenase, and D-dimer were measured. Cerebrospinal fluid (CSF) analysis and electroencephalogram (EEG) were also performed in patients who accepted the risks. Results: A high prevalence of subtle neurological manifestations was found in patients with COVID-19 with only a respiratory clinical picture. Headache, anosmia, dysgeusia, and hypopalesthesia predominated in the early stages, with frequent abnormal findings in the CSF (>70%) and less frequently in the EEG (<20%). Conclusions: Headache, anosmia, dysgeusia and hypoesthesia were frequent at the beginning of the infection, together with abnormal findings in CSF and EEG, without other neurological symptoms or neurological disease.

Introducción: existen condiciones neurológicas severas en pacientes con COVID-19, como: enfermedad cerebrovascular, síndrome de Guillain-Barré, encefalitis, encefalopatía necrotizante hemorrágica aguda y mielitis. Objetivo: describimos que el paciente con SARS-CoV-2 con síntomas respiratorios tiene manifestaciones neurológicas sutiles o subclínicas. Material y métodos: estudio observacional, transversal, analítico, que incluyó pacientes de 18-65 años con síntomas respiratorios y diagnóstico de COVID-19 confirmado. Se excluyeron pacientes intubados, con enfermedades neurodegenerativas crónicas o compromiso neurológico preexistente. Se realizó semiología de la cefalea y exploración neurológica; Se midieron los niveles séricos de glucosa, proteínas, electrolitos, lactato, proteína C reactiva, deshidrogenasa láctica y dímero D. También se realizaron análisis de líquido cefalorraquídeo (LCR) y un electroencefalograma (EEG) en los pacientes que aceptaron los riesgos. Resultados: se encontró alta prevalencia de manifestaciones neurológicas sutiles en pacientes con COVID-19 con solo cuadro clínico respiratorio. Cefalea, anosmia, disgeusia e hipopalestesia predominaron en las primeras etapas, con hallazgos anormales frecuentes en el LCR (>70%) y con menos frecuencia en el EEG (<20%). Conclusiones: la cefalea, anosmia, disgeusia e hipoestesia fueron frecuentes al inicio de la infección, junto con hallazgos anormales en LCR y EEG, sin otros síntomas neurológicos ni enfermedad neurológica.

Implications of starting antiepileptic treatment prior to electroencephalography in first epileptic seizures.

INTRODUCTION: This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure. METHODS: We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72 hours after the seizure, and the factors related with seizure recurrence. RESULTS: We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P = .25) or with the risk of recurrence within 6 months (P = .63). CONCLUSIONS: Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

Factores asociados a epilepsia farmacorresistente en niños atendidos en un hospital de referencia nacional / Factors associated with drug-resistant epilepsy in children treated at a national referral hospital

Antecedentes: Según la Organización Mundial de la Salud (OMS) cerca de 70 millones de personas en el mundo padecen epilepsia. Los países de medianos y bajos ingresos presentan 70-80% de los casos; se estima que afecta 4-13% de los niños hasta los 16 años, de los cuales la epilepsia farmacorresistente (EFR) se desarrolla en 10-23%. Objetivo: Determinar factores de riesgo asociados a EFR en pacientes pediátricos atendidos en Hospital María, Especialidades Pediátricas (HMEP), Tegucigalpa, marzo 2017-marzo 2022. Métodos: Estudio de casos-controles. A partir del total de pacientes menores de 18 años con diagnóstico de epilepsia atendidos en el Servicio de Neurología HMEP, se definió Caso como pacientes con diagnóstico de EFR y Controles como pacientes con epilepsia no farmacorresistente (ENFR). A partir de expedientes clínicos, se evaluaron factores sociodemográficos, antecedentes personales y familiares, factores clínicos, estudios de imagen y electroencefalograma. El estudio fue aprobado por el Comité de Ética Institucional. Resultados: Se analizaron 81 casos y 162 controles. La edad más afectada en casos fue preescolar (35.8%), en controles fue edad escolar (41.4%). El sexo masculino presentó similar distribución en ambos grupos (51.8% y 51.2%). La procedencia rural fue más frecuente en los casos que en controles (58.0% versus 48.8%). Se identificaron los siguientes factores asociados a EFR: Antecedentes familiares de epilepsia (ORa 2.32, IC95%1.22­4.41, p=0.01), alteración focal en examen físico (ORa 2.23, IC95%1.10­4.55, p=0.02), neurodesarrollo anormal (ORa 2.78, IC95%1.18­6.54, p=0.02). Discusión: El control adecuado de las crisis epilépticas incide directamente en la calidad de vida y sobrevida de los pacientes. La identificación correcta de los niños con epilepsia con los factores asociados identificados en este estudio, que coinciden con lo descrito internacionalmente, permitirá hacer un mejor tamizaje y priorizar la referencia temprana a un neurólogo pediatra contribuyendo a mejorar la calidad de vida de los pacientes...(AU)

Electroencefalografía básica para monitores de profundidad anestésica / Basic electroencephalography for anesthesia depth monitors

Resumen: Los monitores de profundidad anestésica permiten guiar el estado hipnótico del paciente durante la anestesia general. Debido a su sencillez, tradicionalmente se han empleado índices de profundidad anestésica, obtenidos a través del procesamiento del electroencefalograma mediante algoritmos matemáticos, para orientar la monitorización del nivel de consciencia. Sus beneficios han sido ampliamente recogidos en la literatura científica; sin embargo, no están exentos de importantes limitaciones. No todos los anestésicos actúan en las mismas dianas moleculares ni dichos índices tienen en cuenta las características propias del paciente (comorbilidades, edades extremas, etcétera). Estas limitaciones podrían reducirse si interpretamos directamente toda la información que nos ofrecen los monitores. Presentamos una revisión que describe los conceptos básicos necesarios para su valoración directa, así como su correlación con los estados de profundidad anestésica del paciente.

Abstract: Anesthesia depth monitors allow to guide the patient's hypnotic state during general anesthesia. Traditionally, anesthetic depth indices have been used due to their simplicity to guide the monitoring of the level of consciousness. They have been obtained by processing the electroencephalogram using mathematical algorithms and their benefits have been widely reported in the scientific literature. However, they are not exempt from important limitations. Neither all anesthetics act on the same molecular targets, nor these mentioned indices take into account the patient's own characteristics (comorbidities, extreme ages, etc.). These limitations could be far reduced if we are able to understand all the information provided by the monitors. We present a review describing the basic concepts necessary for its direct assessment, as well as their correlation with the patient's anesthetic depth states.

Wait and see en epilepsia pediátrica. Nuestra experiencia / Wait and see in paediatric epilepsy. Our experience

Introducción: El tratamiento farmacológico de la epilepsia no es curativo; pretende, en lo posible, evitar crisis en niños que probablemente van a seguir teniéndolas. Pacientes y métodos: El objeto es analizar nuestra experiencia en niños con epilepsia y con primera crisis no sintomática aguda no tratados con antiepilépticos. Se analizó a pacientes atendidos en una consulta de neuropediatría, desde 2017 hasta 2021, que habían sufrido una o más crisis no sintomáticas agudas y a los que no se les había tratado farmacológicamente. Resultados: Sesenta y cinco pacientes cumplieron los criterios de selección. Veinticuatro habían tenido una única crisis, con un tiempo medio de duración de 12 minutos (1-60). En un 66,7% fue nocturna. Un 41,7% presentó electroencefalograma patológico, y un 21%, hallazgos patológicos en la neuroimagen. El tiempo medio de control fue de 2,7 años (0,003-13,6 años). Cuarenta y uno presentaron más de una crisis, con una duración media de nueve minutos (1-60). Cinco pacientes presentaron más de 20 crisis, y el resto, entre dos y 17. Veinticuatro (58,5%) presentaron únicamente crisis nocturnas. Se realizó un electroencefalograma en todos: grafoelementos epileptiformes en el 63,4%; y neuroimagen en todos: patológica en el 4,9%. El tiempo medio de control fue de 3,8 años (0,01-9,1 años). Conclusiones: La frecuencia de las crisis, la patología de base o los resultados de las pruebas complementarias no deberían ser las únicas variables que habría que considerar para iniciar el tratamiento farmacológico antiepiléptico en los niños. Debería prevalecer, por encima de aquéllos, el potencial perjuicio sobre la calidad de vida y el neurodesarrollo, las funciones atencionales y el comportamiento del niño, y siempre consensuar esta decisión con los padres.(AU)

Introduction: Pharmacological treatment of epilepsy is not healing; it tries to avoid seizures, as far as possible, in children who probably would still have them. Patients and methods: Our purpose is to analyse our experience with epileptic children and those who have a first non-symptomatic seizure without pharmacological treatment. Patients seen in a paediatric neurology consultation, from 2017 to 2021, who had suffered one or more acute non-symptomatic crises and who had not been treated pharmacologically, were analysed. Results: Sixty-five patients meet the selection criteria. Twenty-four patients had had a single crisis with a mean duration of 12 minutes (1-60). In 66.7% it was nocturnal. 41.7% presented pathological electroencephalogram, and 21% pathological findings in neuroimaging. The mean control time was 2.7 years (0.003-13.6 years). Forty-one presented more than one crisis, with a mean duration of nine minutes (1-60). Five patients presented more than 20 seizures, the rest between two and 17. Twenty-four (58.5%) presented only nocturnal seizures. An electroencephalogram was performed in all: epileptiform graphoelements in 63.4%; and neuroimaging in all: pathological in 4.9%. Mean control time was 3.8 years (0.01-9.1 years). Conclusions: Seizure frequency, underlying pathology or test results should not be the only variables to take into consideration when starting antiepileptic drug treatment. The repercussion on their quality of life and neurodevelopment should prevail, agreeing on this decision with the parents.(AU)

Crisis epilépticas en urgencias: aspectos clínicos y diagnósticos de una serie de 153 pacientes / Seizures in the Emergency Department: Clinical and diagnostic data from a series of 153 patients

Introducción: Las crisis epilépticas son un motivo de ingreso frecuente en urgencias y requieren una actuación diagnóstico-terapéutica precoz y precisa. Nuestro objetivo fue describir las características clínico-evolutivas de una serie de pacientes con crisis epilépticas atendidos en urgencias.MétodosEstudio observacional retrospectivo de todos los pacientes con crisis epilépticas que ingresaron en urgencias y fueron atendidos por neurología de guardia, de febrero a agosto de 2017.ResultadosSe incluyeron 153 pacientes, correspondientes al 9,9% del total de urgencias neurológicas. La mediana de edad fue de 58 años, el 52,3% fueron mujeres y el 51% tenía antecedente de epilepsia. El 82,4% de las crisis tuvo un inicio focal y la etiología más frecuente fue la enfermedad cerebrovascular (24,2%). Doce pacientes se complicaron con estatus epiléptico (7,8%), lo que se relacionó con mayor puntuación en la escala ADAN (p < 0,001) y con antecedente de epilepsia refractaria (p = 0,002). La mortalidad hospitalaria fue del 3,7%; se asoció a mayor edad (p = 0,049) y a estatus epiléptico (p = 0,018). El 80% de los pacientes sin epilepsia conocida recibió el diagnóstico de epilepsia en urgencias, todos iniciaron tratamiento. El índice Kappa de concordancia para el diagnóstico de epilepsia en urgencias, comparado con el diagnóstico tras un año de seguimiento en la unidad de epilepsia fue 0,45 (se modificó el diagnóstico en el 20% de los pacientes).ConclusionesLas crisis epilépticas constituyen una urgencia neurológica frecuente, con potenciales complicaciones y una morbimortalidad relevante. En pacientes sin epilepsia conocida es apropiado realizar el diagnóstico de epilepsia en urgencias, pero es recomendable un seguimiento posterior en consultas especializadas. (AU)

Introduction: Seizures are a frequent reason for admission to emergency departments and require early, precise diagnosis and treatment. The objective of this study was to describe the clinical and prognostic characteristics of a series of patients with seizures attended at our hospital's emergency department.MethodsWe performed a retrospective, observational study of all patients with seizures who were admitted to our hospital's emergency department and attended by the on-call neurology service between February and August 2017.ResultsWe included 153 patients, representing 9.9% of all neurological emergency department admissions. The median age was 58 years, 52.3% of patients were women, and 51% had history of epilepsy. Onset was focal in 82.4% of cases, and the most frequent aetiology was cerebrovascular disease (24.2%). Twelve patients (7.8%) developed status epilepticus, which was associated with higher scores on the ADAN scale (P < .001) and with history of refractory epilepsy (P = .002). The in-hospital mortality rate was 3.7%, and in-hospital mortality was associated with older age (P = .049) and status epilepticus (P = .018). Eighty percent of patients with no history of epilepsy were diagnosed with epilepsy at the emergency department; all started treatment. The kappa coefficient for epilepsy diagnosis in the emergency department compared to diagnosis after one year of follow-up by the epilepsy unit was .45 (diagnosis was modified in 20% of patients).ConclusionsSeizures are a frequent neurological emergency with potential complications and considerable morbidity and mortality rates. In patients with no known history of epilepsy, the condition may be diagnosed in the emergency department, but follow-up at specialised epilepsy units is recommended. (AU)

Seizures in the Emergency Department: clinical and diagnostic data from a series of 153 patients.

INTRODUCTION: Seizures are a frequent reason for admission to emergency departments and require early, precise diagnosis and treatment. The objective of this study was to describe the clinical and prognostic characteristics of a series of patients with seizures attended at our hospital's emergency department. METHODS: We performed a retrospective, observational study of all patients with seizures who were admitted to our hospital's emergency department and attended by the on-call neurology service between February and August 2017. RESULTS: We included 153 patients, representing 9.9% of all neurological emergency department admissions. The median age was 58 years, 52.3% of patients were women, and 51% had history of epilepsy. Onset was focal in 82.4% of cases, and the most frequent aetiology was cerebrovascular disease (24.2%). Twelve patients (7.8%) developed status epilepticus, which was associated with higher scores on the ADAN scale (P < .001) and with history of refractory epilepsy (P = .002). The in-hospital mortality rate was 3.7%, and in-hospital mortality was associated with older age (P = .049) and status epilepticus (P = .018). Eighty percent of patients with no history of epilepsy were diagnosed with epilepsy at the emergency department; all started treatment. The kappa coefficient for epilepsy diagnosis in the emergency department compared to diagnosis after one year of follow-up by the epilepsy unit was 0.45 (diagnosis was modified in 20% of patients). CONCLUSIONS: Seizures are a frequent neurological emergency with potential complications and considerable morbidity and mortality rates. In patients with no known history of epilepsy, the condition may be diagnosed in the emergency department, but follow-up at specialised epilepsy units is recommended.

Grado de concordancia en una serie de informes de electroencefalogramas ambulatorios del Departamento de Neurofisiología Clínica del Hospital de Clínicas / Coefficient of agreement in a series of reports for ambulatory electroencephalograms at the clinical neurophisiology department of Clinicas Hospital / Grau de concordância em uma série de relatórios de eletroencefalogramas ambulatoriais do Departamento de Neurofisiologia Clínica do Hospital de Clínicas

El electroencefalograma (EEG) es una técnica neurofisiológica encargada de analizar la actividad cerebral utilizada con fines diagnósticos en la epilepsia, pero también en pacientes con encefalopatías agudas y crónicas no epilépticas. Su interpretación debe realizarse por médicos especializados en el área con una formación correcta, actualizada y homogénea para evitar conclusiones disimiles y términos en desuso. Para conocer dentro de una unidad de Neurofisiología Clínica de manera objetiva cómo se interpreta un EEG y su concordancia, comparamos una serie de estudios de EEG ambulatorios a través del grado de concordancia o Kappa entre los observadores. Creemos que es importante conocer las similitudes o diferencias inter observador a fines de corregir los problemas observados y mejorar la calidad asistencial.

An electroencephalogram (EEG) is a neurophysiological technique that measures electrical activity in the brain for diagnostic purposes in epilepsy, and in patients with nonepileptic acute and chronic encelopathies. This test must be performed by physicians who are specialized in the area and have the appropriate updated and uniform training, in order to avoid dissimilar conclusions and outdated terms. We compared a series of ambulatory EEG by analyzing the Kappa or coefficient of agreement rate among observers to objectively learn how an EEG is interpreted and about agreement rates at the Neurophisiology Clinic. We believe it is important to learn about interobserver similarities and differences to allow for the correction of problems noticed and improve the quality of care. Coefficient of agreement in a series of reports for ambulatory electroencephalograms at the clinical neurophisiology department of Clinicas Hospital.

O eletroencefalograma (EEG) é uma técnica neurofisiológica utilizada no estudo da atividade cerebral utilizada no diagnóstico em epilepsia, mas também em pacientes com encefalopatias não epilépticas agudas e crônicas. Sua interpretação deve ser realizada por médicos especialistas na área com formação correta, atualizada e homogênea para evitar conclusões díspares e termos obsoletos. Para conhecer como um EEG e sua concordância são interpretados objetivamente dentro de uma unidade de Neurofisiologia Clínica, comparamos uma série de estudos EEG ambulatoriais através do grau de concordância ou Kappa entre observadores. Acreditamos que é importante conhecer as semelhanças ou diferenças interobservadores para corrigir os problemas observados e melhorar a qualidade do atendimento.

Análisis no-lineal de la onda gamma del electroencefalograma en una prueba de atención e inhibición / Non-linear analysis of the electroencephalogram gamma wave in an attention and inhibition test

Introducción: Durante las últimas décadas se ha estudiado la señal del electroencefalograma desde una perspectiva de matemática no-lineal. Esto permite entender la actividad eléctrica cerebral como un sistema dinámico complejo. Objetivo: Evaluar los exponentes de Hurst y sus correlaciones en la onda gamma durante una tarea de atención alternante e inhibición de la interferencia en estudiantes universitarios. Métodos: La muestra se constituyó por 14 alumnos de educación física. Para evaluar la actividad eléctrica cerebral se utilizó el dispositivo cerebro-interfaz Emotiv Epoc®. La atención alternante se estimó con el test de símbolos y dígitos, mientras que para la inhibición de la interferencia se empleó la prueba de palabras y colores de Stroop. Resultados: En la prueba de atención alternante, cuatro individuos revelaron mayor propensión al caos en el hemisferio derecho, uno presentó más tendencia en el hemisferio izquierdo y dos no tuvieron una predisposición definida. Por otra parte, durante la prueba de inhibición de la interferencia, cinco presentaron variaciones de las medias de Hurst entre las tres láminas del efecto Stroop, sobre todo de la región temporal. Los exponentes Hurst en ambas pruebas fueron inferiores a 0,5. Conclusiones: Durante la prueba de atención se observó un mayor caos de la actividad eléctrica cerebral, sin existir correlaciones entre las regiones estudiadas. Durante la prueba de inhibición las modificaciones de los exponentes de Hurst no presentaron patrones definidos hacia el orden o caos(AU)

Introduction: During the last decades the electroencephalogram signal has been studied from a nonlinear mathematical perspective. This allows understanding brain electrical activity as a complex dynamical system. Objective: To evaluate Hurst exponents and their correlations in the gamma wave during an alternating attention and interference inhibition task in university students. Methods: The sample consisted of 14 physical education students. The Emotiv Epoc® brain-interface device was used to evaluate brain electrical activity. Alternating attention was estimated with the symbols and digits test, while the Stroop words and colors test was used for interference inhibition. Results: In the alternating attention test, four individuals revealed a greater propensity to chaos in the right hemisphere, one showed a greater tendency in the left hemisphere and two had no defined predisposition. On the other hand, during interference inhibition, variations of Hurst average values between the three Stroop effect slices were determined in five subjects, especially in the temporal region. Hurst exponents in both tests were found to be less than 0.5. Conclusions: During the attention test, a greater chaos of brain electrical activity is observed, with no correlations between the regions studied. During the inhibition test, the modifications of the Hurst exponents do not present defined patterns towards order or chaos(AU)

Components of event-related potentials and borderline personality disorder: a meta-analysis.

Background: Borderline personality disorder (BPD) is characterized by symptoms associated with difficulties in emotion regulation, altered self-image, impulsivity, and instability in personal relationships. A relationship has been found between BPD symptoms and altered neuropsychological processes. Studies of event-related potentials (ERP) measured with electroencephalogram (EEG) have found neural correlates related to BPD symptoms. Of note is the P300 component, considered a potential mental health biomarker for trauma-associated disorders. However, no meta-analysis has been found to demonstrate this relationship.Objectives: To evaluate the relationship between the P300 component and BPD symptoms. To evaluate the relationship of other ERP components with BPD symptoms.Methods: The method and procedure were adjusted to the PRISMA checklist. The search was performed in three databases: WOS, Scopus and PubMed. A Random Effects Model was used to perform the analysis of the studies. In addition, a meta-regression was performed with % women, Gini and GDP. Finally, a descriptive analysis of the main results found between P300, other ERP components (LPP, P100 and ERN/Ne) and BPD symptoms was performed.Results: From a review of 485 articles, a meta-analysis was performed with six articles that met the inclusion criteria. A moderate, positive relationship was found between the P300 component and BPD symptoms (REM = .489; p < .001). It was not possible to perform meta-analyses for other ERP components (LPP, P100 and ERN/Ne) due to the low number of articles found.Conclusion: The idea that P300 could be considered for use as a biomarker to identify altered neural correlates in BPD is reinforced. In addition, a moderating effect of inequality (Gini) was detected.

The P300 component of event-related potentials could be considered for use as a possible biomarker to identify altered neural correlates in Borderline Personality Disorder.There is support for the proposition that an altered P300 would be present in disorders related to exposure to traumatic events.P300 could be used to evaluate the therapeutic processes associated with the clinical symptoms of Borderline Personality Disorder.

Recomendaciones para el empleo de técnicas neurofisiológicas en el diagnóstico de muerte encefálica de la Sociedad de Neurofisiología Clínica de las Comunidades de Valencia y Murcia / Recommendations for the use of neurophysiological techniques in the diagnosis of brain death from the Clinical Neurophysiology Society of the Communities of Valencia and Murcia

En España, el trasplante de órganos constituye uno de los mayores retos y trabajo en equipo de los centros hospitalarios. Se estima que en 2020 España aportó a la Unión Europea el 19% de la totalidad de los donantes. El diagnóstico de apoyo confirmatorio recomienda por ley algunas técnicas complementarias en determinados casos, entre ellas las técnicas neurofisiológicas, en especial el uso del electroencefalograma y los potenciales evocados. Estos casos plantean al neurofisiólogo clínico la toma acertada de decisiones tanto clínicas como técnicas para su correcta realización e interpretación. Hasta ahora no existe a nivel nacional un consenso de realización de estas técnicas. Es una revisión bibliográfica actualizada sobre las técnicas neurofisiológicas (electroencefalograma y potenciales evocados), con análisis mediante método Delphi y juicio de expertos del grupo de trabajo de la Sociedad de Neurofisiología Clínica de las Comunidades de Valencia y Murcia. Las técnicas neurofisiológicas permiten ser un apoyo en el diagnóstico de muerte encefálica, tanto de forma confirmatoria como para acortar tiempos de observación. Para su realización se precisan unos mínimos estándares técnicos que permitan realizar de forma óptima los estudios. Especialmente hay que tener en cuenta la medicación, la situación hemodinámica, la ausencia de hipotermia y el grupo de edad. Presentamos la primera guía en castellano elaborada por la Sociedad de Neurofisiología de las Comunidades de Valencia y Murcia para la realización en nuestros hospitales de las técnicas neurofisiológicas en el diagnóstico de muerte encefálica.(AU)

In Spain organ transplantation constitutes one of the greatest challenges and teamwork of hospital centres. It is estimated that in the year 2020 Spain contributed 19% of all donors to the European Union. The confirmatory support diagnosis recommends by law some complementary techniques in certain cases, including neurophysiological techniques, especially the use of electroencephalogram and evoked potentials. These cases require the clinical neurophysiologist to make the right clinical and technical decisions for the correct performance and interpretation of the same. To date, there is no national consensus on the performance of these techniques. Updated bibliographic review on neurophysiological techniques (electroencephalogram and evoked potentials). Analysis by Delphi method and expert judgment of the working group of the Clinical Neurophysiology Society of the Communities of Valencia and Murcia. Neurophysiological techniques can be a support in the diagnosis of encephalic death, both confirmatory and to shorten observation times. In order to perform them, minimum technical standards are required to allow optimal performance of the studies, especially taking into account medication, hemodynamic situation, absence of hypothermia, and age group. We present the first guide in Spanish elaborated by the Society of Neurophysiology of the Communities of Valencia and Murcia for the performance in our hospitals of neurophysiological techniques in the diagnosis of brain death.(AU)

Utilidad del monitoreo continuo del electroencefalograma en el paciente crítico / Utility of continuous electroencephalogram monitoring in the critical patients

Introducción: El monitoreo continuo del Electroencefalograma, es la recogida simultánea de la actividad cerebral y la conducta clínica por un período de horas a días. Por el alto costo de la técnica aún no está muy difundida. Objetivos: Evaluar la utilidad del monitoreo electroencefalográfico continuo en el paciente crítico. Métodos: Se realizó un estudio descriptivo, retrospectivo y longitudinal en 118 sujetos mayores de 19 años ingresados en las unidades de terapia del Hospital Clínico Quirúrgico Hermanos Ameijeiras; entre noviembre 2016 a octubre 2018 con indicación de un Electroencefalograma continuo. Se consideraron variables clínicas y electroencefalográficas: escala de Glasgow, ocurrencia de crisis, diagnóstico, estado al egreso, anormalidad del Electroencefalograma, descargas epileptiformes, sospecha de estatus epiléptico no convulsivo por electroencefalograma entre otras. Los datos se procesaron con test de Chi cuadrado, test de Mc Nemar y test t de student, se empleó un nivel de significación de p≤0.05. Resultados: 60 de los pacientes pertenecían al sexo femenino, la mediana de las edades fue 67,5 años. La escala de Glasgow mostró asociación significativa con el grado de anormalidad del electroencefalograma (p=0,001), es la arreactividad y la discontinuidad de la actividad de base predictores de pobre pronóstico. Se observaron descargas epileptiformes periódicas en 100 pacientes. Se definió estatus epiléptico no convulsivo en 56 sujetos (37,28 por ciento) y en 81 sujetos (68,64 por ciento) el resultado del electroencefalograma motivó una conducta médica. Conclusiones: El monitoreo continuo del electroencefalograma es útil en el diagnóstico y manejo del paciente con episodios no convulsivos, permite formular un pronóstico neurológico y orientó la conducta médica(AU)

Introduction: The continuous monitoring of the electroencephalogram is the simultaneous collection of brain activity and clinical behavior for a period of hours to days. Due to the high cost of the technique, it is not yet widely used. Objectives: To evaluate the usefulness of continuous electroencephalographic monitoring in critically ill patients. Methods: A descriptive, retrospective and longitudinal study was carried out in 118 subjects over 19 years of age admitted to the therapy units at Hermanos Ameijeiras Surgical Clinical Hospital; from November 2016 to October 2018. They were indicated a continuous electroencephalogram. Clinical and electroencephalographic variables were considered, such as Glasgow scale, seizure occurrence, diagnosis, discharge status, electroencephalogram abnormality, epileptiform discharges, suspicion of nonconvulsive status epilepticus by electroencephalogram, among others. The data was processed with the Chi square test, the Mc Nemar test and the student's t test, using significance level of p≤0.05. Results: Sixty patients were female, the median age was 67.5 years. The Glasgow scale showed significant association with the degree of electroencephalogram abnormality (p=0.001). A reactivity and discontinuity of baseline activity are predictors of poor prognosis. Periodic epileptiform discharges were observed in 100 patients. Non-convulsive status epilepticus was defined in 56 subjects (37.28 percent) and in 81 subjects (68.64 percent) the result of the electroencephalogram motivated a medical procedure. Conclusions: The continuous monitoring of the electroencephalogram is useful in the diagnosis and management of patients with non-convulsive episodes, it allows formulating a neurological prognosis and guided medical conduct(AU)

Triphasic waves and brain atrophy in patients with acute encephalopathy / Ondas trifásicas y atrofia cerebral en pacientes con encefalopatía aguda

Abstract Introduction: Triphasic waves (TW) constitute an electroencephalographic pattern associated with certain kinds of encephalopathy. Brain atrophy may be a predisposing factor linked with TW. Objective: To compare the degree of brain atrophy and white matter disease between patients with acute encephalopathy with and without TW. Methods: A retrospective observational study including adult patients with encephalopathy, with and without TW, hospitalized between 2016 and 2017. The degree of brain atrophy and white matter lesion were defined using the Global Cortical Atrophy and Age Related White Matter Changes (ARWMC) scales, respectively. Scores were compared between groups. Mortality rates were registered. Results: Sixteen patients with TW were identified matched by age and sex with 30 patients without TW. The mean age was 80 years in the TW group. Women represented 87.5%. Multifactorial encephalopathy was the most frequent diagnosis followed by metabolic encephalopathy. Patients with TW had more brain atrophy (10.43 vs 6.9, p= 0.03). Mean ARWMC was 9.43±6.5 and 8.5 ±7.89 in patients with and without TW respectively (p= 0.5). Mortality rate was higher in the TW group (31.25 vs 6.66% p= 0.02). Conclusions: Patients with acute encephalopathy and TW had higher degree of cerebral atrophy. It is possible that this structural alteration predisposes to the appearance of TW. There was no significant difference in white matter lesion degree. The mortality of the TW group was high, so future studies are necessary to determine their prognostic value.

Resumen Introducción: Las ondas trifásicas (OT) constituyen un patrón electroencefalográfico asociado con diversas encefalopatías. La atrofia cerebral podría predisponer a su aparición. Objetivo: Comparar el grado de atrofia cerebral y de lesión de sustancia blanca en pacientes con encefalopatía aguda con y sin OT. Métodos: Estudio observacional retrospectivo, incluyó pacientes adultos con encefalopatía aguda con y sin OT internados entre 2016 y 2019. El grado de atrofia cerebral y de lesión de sustancia blanca se definieron según las escalas Global Cortical Atrophy y Age Related White Matter Changes (ARWMC), respectivamente. Se compararon los puntajes entre grupos. Se registró la mortalidad. Resultados: Se identificaron 16 pacientes con OT y 30 sin OT pareados según edad y sexo. La edad promedio del grupo con OT fue 80 años. El 87.5% fueron mujeres. La encefalopatía multifactorial fue el diagnóstico más frecuente seguido de la encefalopatía metabólica. El grado de atrofia fue mayor en pacientes con OT (10.43 vs 6.9, p= 0.03). El puntaje ARWMC fue 9.43 ±6.5 y 8.5 ±7.89 en pacientes con y sin OT respectivamente (p= 0.5). La mortalidad fue mayor en el grupo con OT (31.25 vs 6.66% p= 0.02). Conclusiones: Pacientes con encefalopatía aguda y OT tuvieron mayor grado de atrofia cerebral. Dicha alteración estructural podría relacionarse con la aparición de OT. No hubo diferencias significativas en el grado de lesión de sustancia blanca. La mortalidad del grupo con OT fue elevada. Son necesarios estudios para determinar su valor pronóstico.

Alteración de señal periictal transitoria en resonancia magnética de encéfalo simulando lesión estructural: caso clínico / Reversible peri-ictal MRI signal changes mimicking structural lesion: case report

Resumen La presencia de alteraciones de señal en resonancia magnética (RM) cerebral durante o posterior a un evento epiléptico es cada vez más reconocida en la literatura. Los cambios de señal peri-ictales se considera que sería el resultado de edema cerebral localizado, defecto de la autorregulación cerebral y disrupción de la barrera hemato-encefálica que ocurre durante una crisis epiléptica sostenida. Reportamos el caso de un hombre de 62 años diagnosticado de un síndrome parietal de instalación subaguda cuyo estudio con RM de cerebro mostró una lesión tumefacta con edema cortico-subcortical de ubicación temporo-occipital derecha. El estudio con electroencefalograma mostró actividad ictal en la misma localización. Se inició terapia con fármacos anticonvulsivantes mostrando franca mejoría clínica y electrofisiológica. El control con RM diferido mostró resolución completa de las alteraciones descritas.

The presence seizure-induced signal changes on brain magnetic resonance imaging (MRI) have been increasingly recognized in the literature. The reversible MRI changes in epileptic patients may be the result of a local brain swelling, a defect of cerebral autoregulation and a blood-brain barrier disruption during sustained epileptogenic activity. We report a 62 years old man diagnosed with a subacute right parietal syndrome. MRI shows a tumefactive lesion in right temporo-occipital lobes mimicking a structural lesion. Electroencephalogram (EEG) exhibits continuous ictal activity in the same region. Antiepileptic drugs were started achieving progressive electro-clinical improvement. Subsequent MRI showed remission of signal changes.

Eeg and central nervous system transmitter on athletes training / Eeg e transmissão do sistema nervoso central em atletas em treinamento / Eeg y transmisión del sistema nervioso central em atletas en entrenamiento

ABSTRACT Introduction: Modern EEG technology can evaluate the current level of an individual's central functioning after analyzing the frequency of brain waves (II). The A wave (8 ~ 14Hz) of brain waves (EBG) is one of the most important index parameters in diagnosing the brain's central functioning level. Objective: To explore the effects of different training loads on the brain function of elite archers and provide an objective basis for improving the scientific level of archery training. Methods: The effects of EEG information and central nerve transmitters on athletes' regulation and training were analyzed by testing and statistical methods. Results: Both HL-LLI and LL-HLI stages showed a decreasing trend in EEG complexity. Although the differences between the two stages were not significant all of them were considerably lower than the LL-LLI stage. The number of athletes with central fatigue in both stages showed an increasing trend. Conclusions: Athletes in training also need to focus on recovery after training, which requires a view of scientific training and scientific recovery as an organic whole that cannot be separated. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Introdução: A moderna tecnologia do EEG pode avaliar o nível atual do funcionamento central de indivíduos ao analisar a frequência de ondas cerebrais (II). A onda A (8 ~ 14Hz) de ondas cerebrais (EBG) é um dos parâmetros indicadores mais importantes no diagnóstico do nível de funcionamento central do cérebro. Objetivo: Explorar os efeitos de diferentes cargas de treinamento na função cerebral de arqueiros de elite e fornecer uma base objetiva para melhorar o nível científico de treinamento de arca e flecha. Métodos: Os efeitos de informações do EEG e da transmissão de nervos centrais na regulação e no treinamento de atletas foram analisados através de testes e métodos estatísticos. Resultados: Tanto a fase HL-LLI quanto a LL-HLI demonstraram uma tendência decrescente na complexidade do EEG. Apesar das diferenças entre as duas fases não serem significativas, todas eram consideravelmente mais baixas do que a fase LL-LLI. O número de atletas com fadiga central nas duas fases demonstrou uma tendência crescente. Conclusões: Atletas em treinamento devem também ficar atentos à recuperação após o treinamento, o que exige uma visão de treinamento científico e recuperação cientifica como um todo orgânico que não pode ser separado. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.

Resumen Introducción: La moderna tecnología del EEG puede evaluar el nivel actual del funcionamiento central de individuos al analizar la frecuencia de ondas cerebrales (II). La onda A (8 ~ 14Hz) de ondas cerebrales (EBG) es uno de los parámetros indicadores más importantes en el diagnóstico del nivel de funcionamiento central del cerebro. Objetivo: Explorar los efectos de diferentes cargas de entrenamiento en la función cerebral de arqueros de élite y brindar una base objetiva para mejorar el nivel científico de entrenamiento de arco y flecha. Métodos: Los efectos de informaciones del EEG y de la transmisión de nervios centrales en la regulación y en el entrenamiento de atletas se analizaron a través de pruebas y métodos estadísticos. Resultados: Tanto la fase HL-LLI como la LL-HLI demostraron una tendencia decreciente en la complejidad del EEG. Pese a que las diferencias entre las dos fases no sean significativas, todas eran considerablemente más bajas que la fase LL-LLI. El número de atletas con fatiga central en las dos fases demostró una tendencia creciente. Conclusiones: Atletas en entrenamiento deben también atentarse a la recuperación tras el entrenamiento, que exige una visión de entrenamiento científico y recuperación científica como un todo orgánico que no puede separarse. Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.

Implications of initiating antiseizure drugs prior to the performance of EEG in first epileptic seizures. / Implicaciones de iniciar fármacos antiepilépticos previo a la realización de EEG en primeras crisis epilépticas.

INTRODUCTION: This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure. METHOD: We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72hours after the seizure, and the factors related with seizure recurrence. RESULTS: We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P=.25) or with the risk of recurrence within 6 months (P=.63). CONCLUSIONS: Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

Alteraciones en el electroencefalograma cuantitativo en relación con la coherencia en pacientes con demencia Alzheimer / Quantitative electroencephalogram alterations according to coherency in patients with Alzheimer dementia / Alterações no eletroencefalograma quantitativo em relação à coerência em pacientes com demência de Alzheimer

RESUMEN Introducción: la demencia y dentro de ella la enfermedad de Alzheimer es un síndrome clínico caracterizado por un deterioro persistente y adquirido de las funciones cerebrales superiores. Objetivo: identificar alteraciones en el electroencefalograma cuantitativo respecto a la variable coherencia interhemisférica en estos pacientes. Métodos: estudio descriptivo de corte transversal realizado en el Hospital General Universitario ¨Carlos Manuel de Céspedes¨ de Bayamo, provincia de Granma, en el período comprendido desde 1ro de enero del 2016 a 1ro mayo del 2018. Se estudiaron de forma prospectiva 40 pacientes con posible demencia Alzheimer atendidos en la consulta de Neurología. Determinándose las variables electroencefalográficas: banda y coherencia interhemisférica. Se emplearon pruebas paramétricas y no paramétricas, aplicándose el método de ajuste de Bonferroni. Resultados: predominó el grupo de edades de 60 a 64 años y el sexo femenino. Existieron diferencias significativas respecto a la coherencia interhemisférica en las cuatro bandas de frecuencia teniendo en cuenta los grupos de edades, sexo y lóbulos cerebrales (p˂0.01). Conclusiones: es posible identificar alteraciones en el electroencefalograma cuantitativo en relación con la coherencia interhemisférica en pacientes condemencia Alzheimer, permitiendo establecer diferencias en cuanto al sexo y a los distintos lóbulos cerebrales para cada banda de frecuencias. Caracterizando desde el punto de vista electroencefalográfico la enfermedad.

ABSTRACT Introduction: Alzheimer dementia is a clinical syndrome characterized by a persistent and acquire cerebral dysfunctions. Objective: identify alterations in quantitative electroencephalograms according to interhemispheric coherency was our objective. Methods: a descriptive study with transversal cortes was carried out in Carlos Manuel of Cespedes hospital in Bayamo of Granma province, in the period of January (2016) to May (2018). We determinated the electroencephalographic variables: bands and interhemispheric coherency. We used statistical methods with a parametric and no parametric tests according our muestric. Results: the age group of 60 to 64 years and the female sex predominated. There were significant differences regarding interhemispheric coherence in the four frequency bands taking into account the age groups, sex and brain lobes (p˂0.01).. Conclusions: It is possible to identify alterations in the quantitative electroencephalogram in relation to interhemispheric coherence in patients with Alzheimer's disease, allowing to establish differences regarding sex and the different brain lobes for each frequency band. Characterizing the disease from the electroencephalographic point of view.

RESUMO Introdução: a demência e dentro de la a doença de Alzheimer é uma síndrome clínica caracterizada por uma deterioração persistente e adquirida das funções cerebrais superiores. Objetivo: esta pesquisa é realizada como objetivo de identificar alterações no eletroencefalograma quantitativo quanto à variável de coerência inter-hemisférica nesses pacientes. Métodos: estudo descritivo transversal realizado no Hospital Geral da Universidade ¨Carlos Manuel de Céspedes¨ em Bayamo, província de Granma, no período de 1 de janeiro de 2016 a 1 de maio de 2018. Foram estudados prospectivamente 40 pacientes com possível demência em tratamento no Consulta de neurologia. Determinação das variáveis ​​eletroencefalográficas: banda e coerência inter-hemisférica. Foram utilizados testes paramétricos e não paramétricos, aplicando-se o método de ajuste de Bonferroni. Resultados: predominou a faixa etária de 60 a 64 anos e o sexo feminino. Houve diferenças significativas em relação à coerência inter-hemisférica nasquatro bandas de frequência levando em consideração as faixas etárias, sexo e lobos cerebrais (p˂0,01). Conclusões: épossível identificar alterações no eletroencefalograma quantitativo em relação à coerência inter-hemisférica em pacientes com doença de Alzheimer, permitindo estabelecer diferenças quanto ao sexo e aos diferentes lobos cerebrais para cada faixa de frequência. Caracterizando a doença do ponto de vista eletroencefalográfico.