Changes in the Microstructural Connectome Underlie Visual Memory Deficits in the Prematurely Born at Age 16 Years (I15.004)

OBJECTIVE: To test the hypothesis that alterations in the microstructural connectome are associated with visual memory deficits in prematurely born adolescents compared to term controls at age 16 years. BACKGROUND: Preterm (PT) children without neurosensory findings exhibit deficits in visual-spatial abilities and visual memory. The microstructural alterations underlying these findings remain relatively unexplored. DESIGN/METHODS: 39 PT and term (T) controls at age 16 underwent diffusion MRI (dMRI) to assess the integrity of white matter tracts by fractional anisotropy (FA). Cohorts had similar race, maternal education, age at scan, and gender. These 78 adolescents were part of a cohort of 182 PT with no brain injury and 92 T tested with the Rey-Osterrieth Complex Figure Test (ROCF: visual-spatial ability, visual memory), the Developmental Test of Visual-Motor Integration (VMI: visual-motor integration), and the Grooved Pegboard Test (GPT: fine motor dexterity). RESULTS: Unbiased whole-brain subtraction revealed eight tracts in which FA differed between PT and T (p≤0.05). Controlling for age/gender, PT exhibited negative associations (p<0.05) between FA of corpus genu and all ROCF subscores, between FA of the L and R anterior corona radiata and visual memory (delayed recall), and between FA of the R posterior corona radiata and fine motor dexterity (GPT). In whole-brain voxel-wise analysis, PT showed negative correlations (p<0.05) between FA of the R middle cerebellar peduncle and GPT score, and R and L middle cerebellar peduncles and ROCF copy. GPT scores partially mediated group differences in visual memory measures of the ROCF. CONCLUSIONS: Alterations in the microstructural connectome contribute to persistent visual memory deficits in adolescents born preterm. Specifically, connectivity deficits in the middle cerebellar peduncle correlate with poorer fine motor dexterity, which was shown to be a partial mediator of group differences in visual memory. Study Supported by: NS27116 and Vernon W. Lippard, M.D., Student Summer Research Fellowship Disclosure: Dr. Thomas has nothing to disclose. Dr. Scheinost has nothing to disclose. Dr. Vohr has nothing to disclose. Dr. Lacadie has nothing to disclose. Dr. Constable has nothing to disclose. Dr. Ment has nothing to disclose.