Innovative statistical strategies for combining these data and identifying underlying traits that are part of the genetic liability for ADHD will be used. We believe that combining behavioral, cognitive, EEG and genetic data will identify the most powerful endophentoypes for gene mapping studies in ADHD and yield important information regarding the gene-brain-behavior pathway.
The specific aims of this grant are to: 1) identify specific EEG patterns as likely endophenotypes 2) characterize the EEG endophenotype relative to behavioral and cognitive variation associated with ADHD and 3) test association and linkage of EEG endophenotypes in ADHD. The proposed research makes use of the ongoing UCLA ADHD Genetic Study to collect EEC data on a set of 200 affected sibling pairs (ASPs), their parents, and unaffected siblings for this investigation. The goal of the proposed research is to investigate electroencephalographic (EEC) measures as a biological endophenotype in ADHD and to use it in gene mapping investigations. The identification of risk genes and associated ADHD subtypes may eventually lead to improved diagnostic methods and treatment interventions for children with ADHD. Gene discovery and subsequent elucidation of gene to brain to behavior pathways can be facilitated if etiological heterogeneity is reduced (for example, through use of genetic isolates and/or selection through multiplex families) or if the phenotype can be refined into familial components that may be more closely linked to specific underlying risk genes (i.e. Recent research in ADHD suggests it is a complex behavioral phenotype that is the result of genetic heterogeneity with sample differences likely reflecting variation in relative proportions of various susceptibility genes, their corresponding brain correlates, and background gene effects. These results are supportive of a two-component model of ADHD, with the hyperactive/impulsive component maturing with age and the inattentive component remaining more stable.Attention Deficit Hyperactivity Disorder (ADHD) is a complex behavioral disorder that affects an estimated 5-10% of children in the United States. In the ADHD combined group, the power was found to change at a greater rate than in the ADHD inattentive group, with power levels of the two ADHD groups becoming similar with age.
With increasing age, the EEG of the ADHD inattentive group was found to change at a similar rate to the changes found in the normal group, with the differences in power levels remaining constant. Sex differences between the ADHD subjects and the control group were greater in males than females and matured faster in males. Total power, relative alpha, and the theta/alpha and theta/beta ratios were differentiated between all 3 groups. The EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, absolute and relative power in the delta, theta, alpha and beta bands, and for theta/alpha and theta/beta ratios.
This study investigated age-related changes and sex differences in the EEGs of two groups of children with attention-deficit/hyperactivity disorder (ADHD) combined type and ADHD predominantly inattentive type, in comparison with a control group of normal children.įorty boys and forty girls were included in each group.