Análisis cuantitativo del electroencefalograma para confirmar trastorno funcional frontal en niños con trastorno por déficit de atención con hiperactividad / Quantitative electroencephalogram analysis confirms the presence of frontal lobe deficit among attention deficit disorder with hyperactivity children

Antecedentes: En 1997, Barkley postuló un modelo funcional del trastorno por déficit de atención con hiperactividad (TDAH) basado en la presencia de un déficit central que afecta el desempeño de las funciones ejecutivas. Hallazgos neuroanatómicos y neurofisiológicos relacionan la afectación de los lóbulos frontales con los procesos cognitivos y conductuales de sujetos con TDAH. Objetivo: Evaluar electrofisiológicamente la teoría de Barkley (1997). Sujetos y métodos: Se estudiaron niños entre 7 y 11 años de edad con TDAH (subtipo inatento) y un grupo control. Se compararon los registros electroencefalográficos obtenidos durante la ejecución de una tarea de estimación del tiempo (ES) con el estado de reposo con ojos abiertos (RA). Se conformaron 42 matrices con 5 tipos diferentes de datos electroencefalográficos (19 derivaciones: sistema 10/20) en tres condiciones: RA, ES y ES-RA (potencia absoluta y potencia relativa). Se utilizaron dos métodos de clasificación. Resultados: El análisis de varianza reveló diferencias significativas en el cociente de anterioridad bajo la condición ES-RA. La clasificación con análisis discriminante reportó una efectividad superior a 80%, mientras que una nueva propuesta de clasificación lineal realizó una clasificación superior a 80% con sólo dos derivaciones. Conclusión: Los resultados apoyan las hipótesis de Barkley y sugieren el uso del cociente de anterioridad referido a temporales para caracterizar electrofisiológicamente el TDAH en niños en edad escolar.

BACKGROUND: The Attention Deficit Disorder with Hyperactivity (ADDH) Barkley model predicts concomitant deficits in working memory and in the development of a sense of time as a consequence of poor behavioral inhibition. Objective: To evaluate electrophysiologically Barkley's theory (1997). SUBJECTS AND METHODS: We studied the electroencephalogram (EEG) of fifteen right-handed, normal limit IQ ADDH children (inattentive subtype), aged 7-11 years, and a control group. Subjects were studied at rest, with the eyes open (RO) while performing a time estimation task (ET). Forty-two data matrices were analyzed in three conditions: RO, ET and ET-RO, to assess broad-band spectral parameters; the anteriority, temporal-referenced and laterality quotients (Aq, Aqt and Lq, respectively); and the theta/alpha and theta/beta ratios. RESULTS: Analyses of variance revealed significant differences for ES-RA, in absolute (Aq &Aqt) and relative powers (Aq). Discriminant function analysis was able to predict group membership with an accuracy over 80%, but it decreased slightly when the leave-one-out method was applied Linear discrimination based on right hemisphere Aqt values showed the highest discrimination accuracy. CONCLUSIONS: These results support Barkley's theory, suggesting further evaluation of the temporal-referenced anteriority quotient as a promising electrophysiological tool for the diagnosis and follow up of ADDH children.

Event related brain potentials to semantically incongruent words in children of different ages

In this study, developmental changes of N400 elicited by a simple paradigm to semantic incongruity were examined. Subjects were divided in three different age groups and education levels: Group I (first grade) = 7-8 years, n=10; Group II (third grade) = 9-10 years, n=10; and Group III (sith grade)= 11-12 years, n=10. EEG activity was recorded from 8 monopolar sites referred to linked earlobes. Data showed that the amplitude of the N400 like component did not change significantly from first to sith grade, although the onset latency appeared to be shorter in older children. No significant latency and amplitude changes were found among groups