The functional activity of lissencephalic cortex was studied using FD Glucose positron emission tomography in 8 patients, mean age 7.5 years, at Children’s Hospital of Michigan, Detroit, MI. Two layers of cerebral cortex were differentiated by metabolic activity: an inner layer with 8 to 63% higher glucose utilization rate than the outer layer. Patients with a higher metabolic ratio between the inner/outer layers had greater delays in communication (p=.007) and socialization (p=.03). No difference was found with respect to motor skills. PET studies should provide a more complete analysis of gyral anomalies and clinical outcome in lissencephaly compared to neuroimaging alone. 
COMMENT. PET studies in lissencephaly show that larger metabolic differences between inner and outer cortical layers are associated with greater delays in communicative skills and socialization. The degree of gyral anomaly in lissencephaly is directly correlated with the degree of developmental delay. The majority of patients with type 1 lissencephaly develop epilepsy before age 6 months, and one-third have infantile spasms.