Los movimientos oculares como medida de control ejecutivo en niños con trastorno por déficit de atención con hiperactividad / Eye movements as a measure of executive control in children with Attention Deficit Hyperactivity Disorder

El Trastorno por Déficit de Atención con Hiperactividad (TDAH) está relacionado con dificultades a nivel de control ejecutivo. Nuevas formas de explorar este constructo contribuyen a la precisión diagnóstica, disminuir la prevalencia y la construcción de un consenso objetivo sobre los criterios del TDAH. El objetivo fue establecer las diferencias en el control ejecutivo de un grupo de niños con TDAH (N=22), con respecto al grupo control (N=15), de ambos géneros y de entre 7 y 12 años de edad, escolarizados de la ciudad de Medellín, Colombia. Se implementaron tres parámetros oculares: fijaciones, antisacadas y prosacadas, los cuales fueron registrados continuamente en un equipo de rastreo visual (Tobii T120). Los resultados indicaron un menor tiempo para el grupo con TDAH en fijaciones oculares (p<,001) que miden control de la interferencia. Un mayor número de errores de dirección en el parámetro antisacadas relacionados con el control inhibitorio. Respecto a las prosacadas, que miden la capacidad para iniciar una respuesta motora, no se encontraron diferencias significativas. Se concluyó que la población con TDAH presenta alteración en el control ejecutivo al utilizar el paradigma de rastreo ocular. Se propusieron, además, los movimientos oculares como posible marcador biológico para detectar una población en riesgo de padecer dicho trastorno.

Attention Deficit Hyperactivity Disorder (ADHD) is related to difficulties at the level of the executive control. New ways of exploring this construct contribute to diagnostic accuracy, decrease the prevalence and build an objective consensus on ADHD criteria. The aim of the study was to establish the differences in the executive control of a group of children with ADHD (N=22), with respect to the control group (N=15), of both genders and between 7 and 12 years old, attending school in the city of Medellin, Colombia. Three ocular parameters were implemented: fixings, antisaccade, and prosaccades, which were recorded continuously in a visual tracking equipment (Tobii T120). The results indicated a shorter time for the group with ADHD in ocular fixations (p<0.001) that measure interference control. A greater number of address errors in the antisaccade parameter related to inhibitory control. Regarding the prosaccades, which measure the capacity to initiate a motor response, no significant differences were found. It was concluded that the population with ADHD presents alteration in the executive control when using the eye tracking paradigm. Eye movements were also proposed as a possible biological marker to detect a population at risk of suffering from this disorder.

Educational and Cognitive Predictors of Pro- and Antisaccadic Performance.

Voluntary gaze control allows people to direct their attention toward selected targets while avoiding distractors. Failure in this ability could be related to dysfunctions in the neural circuits underlying executive functions. Interestingly, recent evidence suggests that factors such as years of schooling and literacy may positively influence goal-directed behavior and inhibitory control. However, we do not yet know whether these factors also have a significant impact on the inhibitory control of oculomotor responses. Using pro- and antisaccadic tasks to assess the behavioral responses of healthy adults, we tested the contribution of years of schooling and reading proficiency to their oculomotor control, while simultaneously analyzing the effects of other individual characteristics related to demographic, cognitive and motor profiles. This approach allowed us to test the hypothesis that schooling factors are closely related to oculomotor performance. Indeed, a regression analysis revealed important contributions of reading speed and intellectual functioning to the choices on both pro- and antisaccadic tasks, while years of schooling, age and block sequence emerged as important predictors of the kinematic properties of eye movements on antisaccadic tasks. Thus, our findings show that years of schooling and reading speed had a strong predictive influence on the oculomotor measures, although age and order of presentation also influenced saccadic performance, as previously reported. Unexpectedly, we found that an indirect measure of intellectual ability also proved to be a good predictor of the control of saccadic movements. The methods and findings of this study will be useful for identifying and breaking down the cognitive and educational components involved in assessing voluntary and automatic responses.