Abstract 2030 Neurology Platform, Sunday, 5/2

Since VLBW infants are known to be at increased risk of learning problems at school age, we designed a functional imaging protocol to assess language systems in preterm infants at age 8 years. We hypothesized that measures of functional activation during this language-based task would predict verbal IQ in these children.

Pilot fMRI studies were performed on 13 unanesthetized 8 year old children (mean GA 29.0 +/- 2.0 weeks, mean BW 995 +/- 195 g) who also underwent a complete battery of neuropsychologic testing. FMRI signal intensities were measured as the children listened to segments of a recorded children's story. These were compared with signal intensities when the children listened to corresponding segments of the same story in which prosody was unchanged but phonemes were randomized in time. Widespread increases in signal intensity (activations) were seen in 5 children, suggesting appropriate verbal processing of the story in these children; 8 children had prominent decreases in intensity (deactivations) during the semantic task, consistent with lack of appropriate verbal processing. These 2 distinctly different patterns of activation tended to predict verbal IQ (105.6 +/- 16.8 for activators vs 91.2 +/- 12.7 for deactivators, p=0.1). The activation patterns did not predict performance IQ (93.6 +/- 16.4 vs 88.0 +/- 8.7, p=0.6), indicating specificity of correlation in the language domain and supporting the validity of the task. The patterns of activation were not explained by age, sex, BW, GA, or abnormality on MRI structural imaging.

Children who deactivated during semantic processing tended to be more socially impaired and inattentive than those who activated. This was seen in the WISC-III measure of freedom from distractibility (103.0 +/- 7.7 vs 92.2 +/- 9.1 for activators vs deactivators, p=0.09) and in the withdrawn and socialization subscales of the Child Behavior Check List.

These preliminary data suggest that this innovative language-based fMRI task is associated with verbal IQ in very low birth weight preterm infants at 8 years CA, and that the task may be used to assess the neural basis of language in this high-risk patient population.

(Supp by NS 27116)