Although autism is characterized as a single disorder, there is considerable variability in its clinical presentation, especially with children in the high functioning end of the autism spectrum. This variability may have important implications for understanding individual differences in the age of onset, treatment response and profile of social-emotional development that have been observed among children with this syndrome. Recent research has suggested that measures of EEG frontal asymmetry may provide a marker of important bio-behavioral processes that contribute to these individual differences, such as social-motivation tendencies and emotional valence. Using EEG asymmetry research, combined with literature emphasizing the significant social and emotional difficulties experienced by children in the autism spectrum, it was hypothesized that frontal asymmetry would provide a bio-behavioral marker of individual differences in social motivation and emotional development. Previous research (Sutton, Burnette, Mundy, Meyer et al., 2005) revealed that a subgroup of HFA children with left frontal asymmetry, compared to those with right or intermediate frontal asymmetry, demonstrated fewer social impairments, but higher levels of cognitive flexibility, emotional distress and difficulty with interpersonal relationships. The goal of the current study was to replicate and extend preliminary observations that anterior EEG asymmetry measures provide an important marker of subgroups of higher functioning children with autism who differ from each other on measures of social impairment, comorbid emotional impairment, and cognitive functioning. Results revealed a replication of findings between patterns of EEG asymmetry and emotional impairment which was significantly different from control subjects, but no relations between asymmetry and social-cognitive, cognitive, or executive functioning. A new finding further suggested a relation between EEG asymmetry and early developmental considerations. Results from this study continue to provide evidence that EEG asymmetry is a biological marker of individual differences in high functioning autism which can be used to define diagnostic subgroups. The impact of such research could is critical to understanding the etiology and course of autism, and can ultimately impact treatment and intervention approaches
