Abstracts

Rationale: There is increasing evidence that there is a strong relationship between brain oscillation dysfunction and cognitive impairment. The goal of this study was to determine if frequency and power of EEG background activity are independent predictors of developmental impairment in infants. Methods: We examined the EEGs of 200 consecutive infants between 6-24 months who were referred for an outpatient EEG because of epilepsy or suspected seizures. An electroencephalographer blinded to developmental assessment evaluated two 5 second epochs of EEG free of artifacts during the awake and sleep states. Because of normal age-related changes in frequency and power of oscillations, the infants were stratified into three age groups: 6-12 months (n=86), 12-18 months (n=65) and 18-24 months(n=49). Based on review of the medical records by an author blinded to EEG data, developmental assessments were classified as normal, moderate and severe. Results: Significant differences between groups were found in the awake recordings: i) In the 6-12 month old group with moderate or severe developmental delay a lower mean frequency, greater delta and less theta power was seen than in the normal group; ii) In the 13-18 month old group, theta power was significantly lower in the moderate and severe developmental delay groups compared to the normal group,; iii) In the 18-24 month old group, alpha power was significantly lower in the moderate and severe developmental delay group than the controls. During sleep no significant difference in mean, peak or median frequency or power of alpha, delta, theta and beta were seen in any of the three age groups between the children with normal development and those with severe or moderate delays. Conclusions: This study demonstrates that frequency and power of brain oscillations during wakefulness in infants is a powerful predictor of neurological development. The findings support the notion that normal oscillatory activity is critical for normal cognitive function during development.