Tratamiento ortésico de luxación de cadera derivada de osteomielitis del cuello del fémur. Presentación de dos casos

La osteomielitis es una inflamación ósea causada principalmente por bacterias. En los casos de osteomielitis del cuello del fémur y artritis séptica concomitante, las complicaciones pueden ocasionar, a largo plazo, acortamiento y deterioro articular considerables. Se describen los casos de dos pacientes neonatos, con manifestaciones de hipertermia como signo común; y solo en uno de ellos limitación del movimiento del miembro inferior derecho, contractura en flexión y aducción, dolorosa a la movilización. El diagnóstico se basó en criterios clínicos, imagenológicos y de laboratorio. El tratamiento consistió en el uso de la férula en abducción, lo cual garantizó la reducción concéntrica de la cabeza del fémur en la cavidad acetabular; esto pudo constatarse mediante seguimiento y control de la reducción, a través de radiografía simple de la pelvis en cada consulta. El diagnóstico precoz de la enfermedad determina el empleo de un tratamiento más conservador, además de minimizar la aparición de complicaciones.

Osteomyelitis is a bone inflammation caused mainly by bacteria. In cases of the femur's neck osteomyelitis and concomitant septic arthritis, complications can lead to considerable joint shortening and deterioration in the long term. The cases of two neonatal patients are described, with hyperthermia manifestations as a common sign; and only in one of them limited movement of the right lower limb, flexion and adduction contracture, painful on movement. The diagnosis was based on clinical, imaging and laboratory criteria. The treatment consisted in the use of the abduction splint, which guaranteed the concentric reduction of the femoral head in the acetabular cavity; this could be verified by monitoring and control of the reduction, through simple radiography of the pelvis in each consultation. The early diagnosis of the disease determines the use of a more conservative treatment, in addition to minimizing complications.

Aneurismas intracranianos: epidemiologia e análise morfológica por angiografia digital / Intracranial aneurisms: epidemiology and morphological analysis by digital angiography

Introdução: Aneurismas intracranianos (AIC) são dilatações vasculares de elevada prevalência que podem ser identificadas por angiotomografia, angiorressonância e por angiografia de subtração digital (ASD), exame considerado padrão-ouro. Para AIC não rotos, ainda inexiste consenso absoluto sobre padronização de conduta terapêutica, que depende, intrinsecamente, de aspectos morfológicos e topográficos ao exame angiográfico. Objetivo: Analisar características epidemiológicas, morfológicas e topográficas de AIC não rotos identificados por ASD e as correlacionar com fatores de risco. Método: Foram considerados 160 prontuários eletrônicos de pacientes com AIC não rotos diagnosticados por ASD entre 2014 e 2018. Variáveis consideradas foram aspectos epidemiológicos (gênero, idade e grupo étnico), morfológicos (formato, presença ou ausência de colo e tamanho), topografia, número de AIC por paciente e fatores de risco (hipertensão arterial sistêmica, tabagismo e etilismo), com análise estatística por correlação de Spearman. Resultados: De 160 pacientes, avaliaram-se 207 AIC não rotos. Houve predomínio do sexo feminino, da faixa etária de 60 a 69 anos e da etnia branca. Em relação a fatores de risco, 58,75% apresentavam hipertensão arterial sistêmica. A maioria dos pacientes apresentava um único aneurisma, e a localização mais prevalente foi artéria carótida interna direita. Predominaram aneurismas saculares, pequenos (menor que 7 mm) e de colo largo. Demonstrou-se correlação estatística entre tamanho e localização (p < 0,001), tamanho e tipo de colo (p = 0,0005) e entre formato e tipo de colo (p < 0,001). Conclusão: Houve prevalência de AIC não rotos em indivíduos do sexo feminino de meia idade, brancos e hipertensos, com predomínio de aneurisma sacular não lobulado, único, pequeno, de colo largo em artéria carótida interna direita. Presença de correlação estatística de AIC sacular com colo largo, AIC gigante em artéria carótida interna, e de AIC pequeno com colo largo. [au]

Introduction: Intracranial aneurysms (IA) are vascular dilations that are highly prevalent and that can be identified by angiotomography, angioresonance and digital subtraction angiography (DSA), an exam considered the gold standard. For unruptured IA, there is still no absolute onsensus on standardization of therapeutic conduct, which depends, intrinsically, on morphological and topographic aspects on angiographic examination. Objective: Analyze the epidemiological, morphological and topographic characteristics of unruptured IA identified by DSA and to correlate with risk factors. Method: 160 electronic medical records of patients with unruptured IA diagnosed by DSA between 2014 and 2018 were considered. Variables considered were epidemiological (gender, age and ethnic group), morphological aspects (shape, presence or absence of neck and size), topography, number of IA per patient and risk factors (systemic arterial hypertension, smoking and alcoholism), with statistical analysis by Spearman correlation. Results: Out of 160 patients, 207 unruptured IA were evaluated. There was a predominance of females, aged 60 to 69 years and white ethnicity. Regarding risk factors, 58.75% had systemic arterial hypertension. Most patients have a single aneurysm, and the most prevalent location was the right internal carotid artery. Saccular, small (less than 7 mm) and large-necked aneurysms predominated. There was a statistical correlation between size and location (p <0.001), size and type of neck (p = 0.0005) and between shape and type of neck (p <0.001).Conclusion: Prevalence of unruptured IA in middle-aged, white and hypertensive women, with a predominance of a single small non-lobulated saccular aneurysm with a large neck in the right internal carotid artery. Correlation of saccular IA with large neck, giant IA in internal carotid artery, and small IA with large neck. [au]

Treatment of Serious Occlusal Instability Associated with Temporomandibular Disorders (TMDs) Through Implant and Dynamic Occlusal Schemes Rehabilitation. A Case Report

ABSTRACT: A case report of 35 years old male patient, partially edentulous with occlusal instability, Disc Displacement with Reduction (DDWR), Local Muscle Soreness (LMS) and Alteration of vertical dimension is presented. Rehabilitation was planned to achieve predictability of long-term treatment, providing static and dynamic occlusal stability. A therapeutic occlus ion with premature contact in the right premolar sector was planned. Implants and cemented/screwed crowns were used to obtain contacts in the molar area. The restoration of dynamic occlusal schemes was made by direct adhesive technique in the anterior sector and Curve of Spee (COS) compensation with temporary anchoring for molar inclusion was used. Patient presents objective and subjective improvements associated with the treatment performed. Temporomandibular disorder is stabilized and controlled by a specialist.

RESUMEN: Se presenta el caso clínico de un paciente masculino de 35 años, parcialmente desdentado con inestabilidad oclusal, Desplazamiento Discal con Reducción (DDWR), Dolor Muscular Local (LMS) y Alteración de la dimensión vertical. La rehabilitación se planificó para lograr la previsibilidad del tratamiento a largo plazo, proporcionando estabilidad oclusal estática y dinámica. Se planificó una oclusión terapéutica con contacto prematuro en el sector premolar derecho. Se utilizaron implantes y coronas cementadas / atornilladas para obtener contactos en la zona de los molares. La restauración de esquemas oclusales dinámicos se realizó mediante técnica de adhesivo directo en el sector anterior y se utilizó compensación de Curva de Spee (COS) con anclaje temporal para inclusión molar. El paciente presenta mejoras objetivas y subjetivas asociadas al tratamiento realizado. El trastorno temporomandibular es estabilizado y controlado por un especialista.

Desrotación interfragmentaria y reducción por vía percutánea de la fractura supracondílea de húmero desplazada / Interphragmental debridement and percutaneous reduction of displaced humeral supracondylar fracture

La fractura supracondílea de húmero tiene una alta incidencia en la primera década de la vida. Representa el 3-16 % de todas las fracturas en niños, solo superada por la fractura distal del radio; además constituye el 53-67 % de las fracturas del codo en este grupo de edad. La magnitud del desplazamiento de los fragmentos, la severidad de las lesiones de partes blandas y la posibilidad de complicaciones neurovasculares, la convierten en una lesión grave que requiere tratamiento de urgencia. En determinados casos las condiciones locales de la fractura impiden la manipulación adecuada de los fragmentos, por lo que la reducción no se logra de la manera correcta y la fijación es inestable, haciéndose necesaria una intervención quirúrgica para alcanzar la reducción. En este artículo se expone un nuevo método que consigue la reducción anatómica y permite la fijación estable por vía percutánea. Además, se muestran los resultados obtenidos en dos casos clínicos en los que se aplicó dicho método.

Supracondylar humerus fracture has a high incidence in the first decade of life. It represents 3-16% of all fractures in children, only surpassed by radius distal fracture; it also constitutes 53-67% of elbow fractures in this age group. The magnitude of the fragments displacement, the severity of soft tissue lesions and the possibility of neurovascular complications, make it a serious injury requiring emergency treatment. In certain cases the fracture local conditions the prevent the fragments adequate manipulation, so the reduction is not achieved in the correct way and the fixation is unstable, requiring surgical intervention to achieve reduction. In this article a new method is presented that achieves the anatomical reduction and allows stable fixation by percutaneous way. In addition, the results obtained in two clinical cases in which this method was applied are shown.

Correlación entre ecografía y radiografía en función del diagnóstico del desarrollo displásico de la cadera / Correlation between ultrasound and radiography for the diagnosis of Dysplastic Hip development

Algunos autores sugieren utilizar la ecografía en los primeros tres meses de vida, dejando la radiografía para etapas posteriores a los tres o seis meses, cuando la cabeza del fémur se muestra osificada. Desde el punto de vista de los autores, esta distinción no es válida, si se considera como sustento teórico práctico el conocimiento de la anatomía radiográfica y ecográfica de la cadera, así como una adecuada interpretación de las imágenes. Para ilustrar la correspondencia entre ambos tipos de estudios, se identifican los puntos de referencia anatómicos comunes para las respectivas imágenes. El objetivo es mostrar evidencias de la efectividad de la aplicación de los dos métodos como complemento del diagnóstico clínico del desarrollo displásico de la cadera. Se concluye que existe una estrecha relación entre ellos, la cual puede ponerse en función del diagnóstico de la enfermedad, e incluso de su seguimiento evolutivo, independientemente de la edad del niño, durante el primer año de vida.

Some authors suggest using ultrasound in the first three months of life, leaving radiography for stages after three or six months, when the femoral head is ossified. From our the authors´ of view, this distinction is not valid if the knowledge of the hip radiographic and ultrasound anatomy is considered as practical theoretical support, as well as an adequate interpretation of the images. To illustrate the correspondence between both types of studies, the common anatomical reference points for the respective images are identified. The aim is to show evidence of the effectiveness of the application of both methods as a complement for the clinical diagnosis of dysplastic hip development. It is concluded that there is a close relationship between them, which can be based on the diagnosis of the disease, and even its evolutionary follow-up, regardless the child's age, during the first year of life.

Retardo en la osificación del núcleo de la cabeza del fémur. ¿Observación u ortesis? / Delay in ossification of the femoral head nucleus. Observation or orthoses?

El desarrollo displásico de cadera es una afección ortopédica de la infancia, que puede tener diferentes grados de severidad. En los casos más severos, como la displasia subluxación y luxación, se requiere del uso de ortesis ortopédicas. El hecho de que el núcleo de osificación de la cabeza del fémur no aparezca osificado en la radiografía a los seis meses de edad, es uno de los criterios a considerar para el diagnóstico de displasia. Para iniciar el tratamiento ortésico, deben analizarse las características cualitativas de acetábulo, y se tendrá en cuenta que los tratamientos no están exentos de complicaciones. En este trabajo, se ilustra a través de imágenes radiográficas, el punto de vista de los autores acerca de la toma de decisiones terapéuticas, en un paciente con retardo en la osificación del núcleo de la cabeza del fémur.

Dysplastic hip development is an orthopedic condition of childhood, which may have different degrees of severity. In more severe cases, such as dysplasia, subluxation and dislocation, the use of orthopedic orthoses is required. The fact that the ossification nucleus of the femoral head does not appear ossified on the radiograph at six months of age is one of the criteria to be considered for the diagnosis of dysplasia. To begin the orthotic treatment, the qualitative characteristics of acetabulum must be analyzed, and it will be taken into account that the treatments are not exempt of complications. In this work, the authors' point of view on therapeutic decision making is illustrated by radiographic images in a patient with a delayed ossification of the femoral head nucleus.

Metodología para medir la cadera en etapa cartilaginosa desde el punto de vista radiográfico / Methodology to measure cartilaginous stage from the radiographic point of view

Algunos autores plantean que la medición radiográfica de la cadera en etapa cartilaginosa, se dificulta por la no visualización en las radiografías del núcleo osificado de la cabeza del fémur, lo que compromete la determinación exacta de la relación entre cabeza femoral y acetábulo. En este artículo se expone la metodología para la evaluación radiológica de la cadera con desarrollo displásico desde la etapa cartilaginosa. Para ello, se utilizó una radiografía simple anteroposterior de la pelvis en etapa cartilaginosa, donde la cabeza del fémur no es visible. La metodología propuesta tiene como elemento inicial la determinación de puntos de referencia, presentes desde la etapa de recién nacido y sobre los cuales se realizan mediciones y ángulos, lo que permite establecer grupos diagnósticos y dar seguimiento en el tiempo hasta la curación de la afección.

Some authors suggest that hip radiographic measurement in the cartilaginous stage is difficult by the non-visualization in the x-rays of the femoral head ossified nucleus, which compromises the exact determination of the relation between the femoral head and the acetabulum. This article describes the methodology for radiological evaluation of the hip with dysplastic development from the cartilaginous stage. For this, a simple anteroposterior pelvis radiograph was used in the cartilaginous stage, where the femoral head is not visible. The proposed methodology has as initial element the determination of reference points that are present from the newborn stage and on which measurements and angles are made. It allows to establish diagnostic groups and to provide follow up in time until curing the condition.

Control de la reducción en caderas con desarrollo displásico mientras se usa férula en abducción / Control of hip reduction with dysplastic development while using splinting abduction

El éxito del tratamiento de la cadera con desarrollo displásico está relacionado al diagnóstico precoz y al tratamiento empleado. El tratamiento ortésico debe garantizar la remodelación de la cadera displásica, para ello se deben cumplir requisitos de flexión y abducción de caderas en grados adecuados para evitar la aparición de complicaciones. Un medio para corroborar que estos requisitos se cumplen, es el estudio radiográfico de la pelvis del paciente con el dispositivo ortésico colocado, a cuya imagen resultante se le realizan tres mediciones. Se presentan las imágenes del caso de una paciente femenina de cuatro meses de edad, con signos clínicos y radiográficos de desarrollo displásico de la cadera, con el objetivo de mostrar los adecuados grados de flexión que debe proporcionar la ortesis. La aplicación de estos métodos ofrece mayor seguridad acerca de la reducción lograda y garantiza la remodelación articular hacia la normalidad en la cadera con desarrollo displásico.

The success of hip with dysplastic development treatment is related to the early diagnosis and the treatment used. Orthotic treatment should guarantee the remodeling of the dysplastic hip, for which it is necessary to comply with hip flexion and abduction requirements in adequate degrees to avoid the appearance of complications. Radiographic study is a way to corroborate that these requirements are met in patients´ pelvis with the orthotic device placed, to whose resulting image three measurements are made. The case images of a four months female patient, with clinical and radiographic signs of dysplastic hip development are presented, in order to show the appropriate degrees of flexion that the orthosis should provide. The application of these methods offers greater certainty about the reduction achieved and guarantees the joint remodeling toward normality in the hip with dysplastic development.

Comparación entre ensambles de Phyllophaga (Coleoptera: Melolonthidae) del Occidente de Cuba / Comparison between Phyllophaga (Coleoptera: Melolonthidae) assemblages in Western Cuba

ResumenEl archipiélago cubano cuenta con 79 especies de Phyllophaga (Coleoptera: Melolonthidae), con un 98.6 % de endemismo, lo cual le confiere al grupo importancia desde el punto de vista de biodiversidad y económica, al ser algunas especies plagas de cultivos. El objetivo de este trabajo fue determinar la relación entre la composición y estructura de los ensambles de Phyllophaga y el tipo de hábitat (en cuanto a formación vegetal y grado de alteración humana). Durante la estación de lluvia fueron muestreadas 17 localidades del occidente de Cuba, las que difieren en cuanto al tipo de hábitat y grado de alteración. Las recolectas fueron realizadas con una trampa de luz tipo pantalla (McFarland, 1966). Se recolectaron 1 153 ejemplares de 24 especies de Phyllophaga. La abundancia total de individuos recolectados varió entre 10 y 306 y la riqueza de especies entre dos y nueve especies. Phyllophaga dissimilis (Chevrolat) fue la especie más abundante y la de mayor frecuencia de ocurrencia. De manera general, las localidades menos antropizadas reflejaron comunidades más ricas y equitativas, aunque estas características también la tuvieron dos sitios que tienen grado de alteración intermedia. El escalado multidimensional no métrico, reflejó que las muestras más semejantes entre sí fueron las pertenecientes a lugares muy antropizados, esta semejanza estuvo dada principalmente por la abundancia de Phyllophaga dissimilis, P. insulaepinorum y P. puberula. La distancia geográfica no se relacionó con la similitud de los ensambles.

Abstract:The Cuban archipelago has 79 Phyllophaga species with a 98.6 % of endemism, which makes the group ecologically and economically important, as some species are classified as crop pests. The aim of this study was to determine the relationship between the composition and structure of the Phyllophaga assemblages with their habitat type, considering both plant structure and level of human habitat disturbance. A total of 17 locations were sampled in Western Cuba during the rainy seasons of the period from 2011 to 2015; these differed in habitat types (forests and agroecosystems). Samplings followed standard methods and were made once with a light trap screen in each locality. A total of 1 153 individuals of 24 Phyllophaga species were collected. The total abundance of collected individuals varied between 10 and 306, and species richness between two and nine species. The most abundant species was Phyllophaga dissimilis (Chevrolat) which also had the highest frequency of occurrence. Generally, less anthropized sites reflected richer and equitative communities; although these characteristics appeared in two sites that showed intermediate degree of disturbance. The non-metric multidimensional scaling showed that the most similar samples were those of the very anthropized sites; this similarity was given mainly by the abundance of Phyllophaga dissimilis, P. insualepinorum and P. puberula. Besides, the geographical distance was not related to the similarity of these assemblages. Rev. Biol. Trop. 65 (1): 351-363. Epub 2017 March 01.

Peptide Characterization of Mature Fluorotic and Control Human Enamel

Abstract Exposure to high fluoride levels during amelogenesis causes enamel fluorosis. This study aimed to determine and compare the amino acid sequences in the enamel of fluorotic and control teeth. This investigation included enamel samples obtained from erupted and non-erupted third molars with either TF grade 4-6 (n=7) fluorosis or no sign of fluorosis (controls, n=7). The samples were kept frozen at -20 °C until protein extraction. Samples were etched and processed with a cocktail of proteinase inhibitors and immediately analyzed. Matrix Assisted Laser Desorption/Ionization-Time-Of-Flight/Time-of-Flight Mass Spectrometry (MALDI-TOF/TOF) followed by MASCOT search aided the peptides analysis. The more abundant peptides bore the N-terminal amelogenin sequences WYQSIRPPYP (which is specific for the X-encoded amelogenin) and MPLPPHPGHPGYINF (which does not show sexual dimorphism) were not different in control or fluorotic enamel. There was no missing proteolytic cleavage in the fluorotic samples, which suggested that the increased amount of protein described in fluorotic enamel did not stem from the decreased ability of proteinases to cleave the proteins in humans. This study showed how to successfully obtain peptide from superficial enamel. A relatively low number of teeth was sufficient to provide good data on the actual peptides found in mature enamel.

Resumo Exposição a altos níveis de flúor durante a amelogênese causa fluorose no esmalte. Este estudo tem como objetivo determinar e comparar as sequências de aminoácidos presentes no esmalte de dentes controles e fluoróticos. A investigação incluiu amostras de esmalte obtidas de terceiros molares erupcionados e não erupcionados, ambas ou com grau de fluorose TF 4-6 (n=7) ou sem sinais de fluorose (controles, n=7), congelados a -20 oC até a extração das proteínas. As amostras sofreram ataque ácido e foram processadas utilizando um coquetel de inibidores de proteinases, sendo imediatamente analisadas. MALDI-TOF/TOF seguido pela pesquisa com MASCOT foram utilizados para a análise dos peptídeos. Os peptídeos mais abundantes foram das amelogeninas com sequências N-terminal WYQSIRPPYP (que é codificada especificamente pela amelogenina X) e MPLPPHPGHPGYINF (que não apresenta dimorfismo sexual algum), não havendo diferenças entre dentes fluoróticos e controles. Nenhuma alteração na proteólise ocorreu nas amostras fluoróticas, o que sugere que o aumento na quantidade de proteínas existentes nas amostras fluoróticas não está correlacionada a habilidade das proteinases em clivar as proteínas em humanos. Este estudo mostrou como extrair com sucesso peptídeos do esmalte superficial. Um número relativamente baixo de dentes foram suficientes para se obter ótimos dados a respeito de peptídeos encontrados no esmalte maduro.

Clasificación radiográfica de la cadera con desarrollo displásico / Radiographic Classification of Developmental Dysplasia of the Hip

Por más de una década, la férula en abducción de cadera ha sido el método de tratamiento del desarrollo displásico de caderas, en el Hospital Pediátrico Universitario Paquito González Cueto de Cienfuegos. El objetivo de este trabajo es exponer la clasificación dinámica para las caderas con desarrollo displásico, desde el punto de vista radiográfico. Para ilustrar la clasificación se utilizaron esquemas representativos y radiografías de pacientes portadores de diferentes grados de la afección. El comportamiento dinámico de los parámetros radiográficos utilizados en la clasificación, permite realizar agrupaciones diagnósticas antes, durante y después del tratamiento, en función de evaluar los resultados finales de este.

For over a decade, abduction splinting has been the method of treatment for developmental dysplasia of the hip in the Paquito González Cueto University Pediatric Hospital. This paper is aimed at presenting the dynamic classification for this condition from a radiographic point of view. Representative schemes and radiographies of patients with various stages of developmental hip dysplasia were used for illustrating this classification. The dynamic behavior of the radiographic parameters used in the classification allows gathering diagnostic groups before, during and after treatment in order to assess its final results.

Estandarización de la Figura de Taylor en población mexicana / Taylor's Figure Standardization on Mexican population

In order to perform a neuropsychologycal evaluation, the clinician may use several instruments; nevertheless, most of them have been designed for use on populations with very different social and cultural backgrounds from that of Mexico. This makes the research on the standardization of methods of evaluation for Mexican population a very important task for both clinical and research settings. Normative data obtained from Mexican population is necessary because it provides the clinician that works with Mexican patients with a reference framework that allows him or her to correctly classify a particular behavior of an individual as normal or abnormal and thus make specific evaluations and cooperate in diagnostic. Researchers interested on cognitive functioning also require qualitative and quantitative equivalent instruments that may allow them to objectively evaluate the efficacy of short-time interventions as in a pre- and post-treatment experimental designs; and it is precisely for this reason that Taylor's figure was developed. Taylor's figure (TF) was originally designed as an alternative to Rey-Osterrieth's complex figure (ROCF), in order to use it in test-retest situations. Similar to ROCF, Taylor's figure has two modalities: copy and memory. The former evaluates constructional praxia, while the latter measures immediate recalling. Parallel tests, that is, different tests that evaluate the same variables, are useful because they reduce the measurement error involved in applying the task twice to the same person (i.e. learning), thus increasing the validity of follow up evaluations of cognitive functioning. <

Dentro del ámbito neuropsicológico existe una serie de instrumentos de evaluación que en su mayoría han sido diseñados en un contexto sociocultural diferente al nuestro, por lo que es importante contar con pruebas neuropsicológicas estandarizadas en sujetos mexicanos. Desde esta perspectiva, los datos de una población normativa nos permiten tener un marco de referencia para comparar y establecer diagnósticos diferenciales dentro de la práctica clínica. Asimismo, dentro del ámbito de la investigación se requieren instrumentos que en teoría sean equivalentes en cuanto a la función que evalúan para llevar un seguimiento sobre el funcionamiento cognoscitivo de una población en particular a lo largo del tiempo. La Figura de Taylor se diseñó como una alternativa a la Figura Compleja de Rey-Osterrieth para aplicarla en situaciones de test-retest. Consta de dos modalidades: una de copia que evalúa la praxia de construcción y otra de memoria inmediata. El término <

Potenciales relacionados con eventos y comorbilidad en un grupo de adolescentes con trastorno por déficit de atención con hiperactividad / Event-related potentials and commorbidity in a group of teenagers with Attention Deficit Hiperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) is a neuro-developmental disorder clinically characterized by three core symptoms: deficits in attentional processes, failure in inhibitory control -usually expressed through behavioral and cognitive impulsiveness-, and motor and verbal restlessness. Deficit in attentional resources is the main alteration in patients with this disorder. Attention can be considered as a neurocognitive state of neural preparation that precedes both perception and action. Attention focalizes consciousness in order to filter the constant flux of sensorial information, solve competence between stimuli for parallel processing and recruit and activate cerebral regions necessary to accomplish appropriate responses. Event-related potentials (ERPs) are a technique that has proven useful in the gathering of valuable information in the study of ADHD. One of the most studied ERPs is the P300 component. The most robust finding in the P300 research in ADHD is a decrease in the amplitude of the component in patients when compared to normal controls. This finding is usually interpreted as an evidence for a deficit in attention. ADHD usually presents commorbidity with several disorders; research shows that up to 87% of the children with ADHD present commorbidity with another disorder, up to 60% has either a behavioral or affective disorder commorbid with ADHD. Due to the wide range of disorders that are usually associated with this entity, it is useful in the research of commorbidity to use dimensional diagnostics, that is, a patient with ADHD may have commorbidity with an externalized disorder (EXT) (i.e. oppositionist defiant disorder); an internalized (INT) disorder (i.e. anxiety or affective disorder); or both an externalized and an internalized disorder (MIX). Commorbidity may have important implications in the electrophysiology of ADHD since no homogeneous results have been evident in the scarce research on the subject. Taking into account these considerations, the following experiment was designed in order to answer the question: Patients with the same main diagnostic, ADHD, but different commorbidities (INT and MIX) show different psychophysiological patterns of activation, as measured by ERPs to a continuous performance task? Sixteen patients diagnosed with ADHD by a specialist were recruited. Diagnosis was corroborated by a semi-structured interview, K-SADS-PL-MX, eight of them with an externalized comorbid (EXT) disorder, and eight of them with at least two comorbid disorders, one externalized an one internalized (MIX). A control group (CON) of eight normal subjects with no psychiatric diagnostic and matched by sex was also recruited. All subjects were between 13-16 years old with no history of Central Nervous System damage and normal IQ in the Weschler Intelligence Scale for Children. Brain electrical activity was recorded in the 19 derivations of the 10-20 international system while subjects executed a continuous performance task (CPT). Comparisons of behavioral data between groups showed some significant differences. A one-way ANOVA found differences between groups in the mean reaction time to the first part of the CPT and in the number of false positives in the second part. Electrophysiological data was analyzed with a non-parametrical multivariate test of permutations. When comparing responses to the frequent stimulus with responses to the infrequent, statistically significant differences were found in every subject; such differences share the topography and latency characteristics of the P3b component. When comparing the amplitude of this component between the groups, only two statistically significant differences were found. First, the EXT group presented a greater amplitude of the component elicited by the first part of the task in a latency of 425 to 445 msec in the parietal region of the medial line than the CON group. Second, also in response to the first part of the task, the amplitude of the CON group was bigger than that of the MIX group in a latency between 355 and 420 msec in the left temporal anterior region. No other comparison yielded significant results. When comparing between groups, mean reaction time to the first part of the task was the only behavioral variable that adequately distinguished control and patients. Even though controls executed significantly faster, they maintained the same efficacy as no differences were found in the number of errors or correct responses. This result is not surprising due to the fact that long reaction times usually denote inattention and so the fact that both groups of patients execute slower than the controls may be interpreted as a sign that, in spite of having different commorbidities, inattention is still a common problem in every patient of the sample. On the second part of the task, only the number of false positives showed statistically significant differences. However, in a posterior analysis of the data, it was evident that such differences were only between the EXT and the CON groups, with the EXT group presenting significantly more errors. False positives, especially on the second part of the task, are a measure of behavioral inhibition. Failure in inhibitory control is one of the three main symptoms of ADHD. However, some have proposed it as the main characteristic of the disorder. Analysis of the electrophysiological response to the first part of the task showed characteristic profiles of execution for each group. First, the P300 component was smaller in amplitude in the MIX group than in the control group and, even though differences were significant only in one derivation (T3), several other electrode sites more typically associated with the P300 component (C3, C4, P3, P4 and Pz) showed similar tendencies that did not reach statistical significance. Second, EXT patients had greater amplitude of the same P300 component in Pz than CON subjects. This result may seem to contradict most of the research on ADHD and P300. Nevertheless, considering the behavioral data, specially that no differences in correct responses were found between patients an controls, it is posible to assert that the greater amplitude of the component represents an overactive compensation in attentional circuits, necessary in the EXT group in order to execute at the same level of non-ADHD subjects. The results of this study present with information on a poorly reasearched subject: comorbidity and electrophysiology on ADHD.

La principal función afectada en el trastorno por déficit de atención con hiperactividad (TDAH) es la atención, la cual puede considerarse como un estado neurocognoscitivo cerebral de preparación que precede tanto a la percepción como a la acción. Los potenciales relacionados con eventos (PREs), una técnica útil en el estudio de la atención en esta entidad, pueden definirse como los cambios en la actividad eléctrica cerebral asociados temporalmente con la aparición de un evento, ya sea un estímulo o un proceso cognitivo. Con esta técnica es posible explorar las representaciones eléctricas de los procesos sensoriales y congnoscitivos con una alta resolución temporal. Uno de los PREs más estudiados en el TDAH es el P300, un componente positivo que ocurre en una latencia de alrededor de los 300 mseg. El hallazgo más contundente en el estudio del P300 en pacientes con TDAH es un decremento en la amplitud al compararlos con sujetos controles, lo cual suele ser interpretado como expresión de una atención deficiente. Por otro lado, el TDAH suele presentarse en comorbilidad con diferentes trastornos y siendo la presentación más infrecuente del síndrome es el TDAH <>. El presente estudio tiene como objetivo analizar si pacientes con el mismo diagnóstico principal, pero con diferente comorbilidad, presentan patrones de activación psicofisiológicos diferentes. Se evaluaron 16 pacientes diagnosticados con TDAH-M: ocho con comorbilidad EXT y ocho con comorbilidad MIX, así como ocho sujetos controles sanos. Tanto los pacientes como los controles realizaron las dos partes de una tarea de ejecución continua, mientras se registraba la actividad eléctrica cerebral en las 19 derivaciones del sistema internacional 10-20. En las medidas conductuales, las comparaciones intragrupos no arrrojaron diferencias estadísticamente significativas. Sin embargo, en las comparaciones entre grupos por medio de la prueba ANOVA de una vía sí aparecieron diferencias estadisticamente significativas (F=5.544 y p=0.012) entre los grupos en la media del tiempo de reacción en la parte 1 del CPT y en la variable errores por comisión en la parte 2 (F=3.975 y p=0.034). De las comparaciones electrofisiológicas realizadas entre grupos, sólo dos resultaron estadísticamente significativas. En primer lugar, el grupo EXT presentó mayor amplitud del componente que el grupo CON en una latencia entre 425-445 mseg en la región parietal media. En segundo lugar, el grupo CON tuvo mayor amplitud que el grupo MIX entre los 355-420 mseg en la región temporal anterior izquierda; ambos resultados se obtuvieron en la primera parte de la tarea. Ninguna otra comparación resultó significativa. Que el tiempo de reacción en la primera parte de la tarea fuera la única variable que distinguió entre pacientes y controles parece sugerir que, a pesar de que los pacientes tenían diferentes comorbilidades, la inatención sigue siendo el problema común a todos los pacientes de la muestra. La comparación de los datos electrofisiológicos entre grupos ofreció perfiles de ejecución característicos para cada subgrupo. Por un lado, el componente P300 fue de menor amplitud en los pacientes MIX que en los sujetos control (aunque sólo fue significativo en una derivación T3), lo cual concuerda con la bibliografía científica al respecto. Por otro, que los pacientes EXT presentaran mayor amplitud del componente P300 en Pz que los sujetos CON parece contrario a otros hallazgos de la bibliografía. Sin embargo, si se toma en cuenta que conductualmente tanto pacientes como controles ejecutaron al mismo nivel se puede sugerir que en los pacientes EXT el déficit de atención subyacente se compensa de manera exitosa y tal proceso se refleja en la amplitud de los PREs. Los resultados de este estudio proporcionan datos sobre cómo la comorbilidad incide en la respuesta electrofisiológica de los pacientes con TDAH.