The developmental outcome of children prenatally diagnosed with mild isolated ventriculomegaly: Cognitive and adaptive functioning

The purpose of the study was to determine if fetal mild isolated ventriculomegaly (MIVM) is associated with developmental difficulties during infancy and early childhood. Of particular concern, is the intellectual functioning of children diagnosed with this neuroanatomical abnormality. Current research on this condition is sparse. While the existing literature is limited by methodological problems, preliminary data suggests that fetal MIVM is associated with increased rates of cognitive impairment. These children need to be evaluated in order to provide prospective parents with reliable information about the outcome of fetal MIVM. In addition, should infants diagnosed prenatally with fetal MIVM demonstrate developmental difficulties they will need to be targeted for early intervention services.

The obstetrics and gynecology department of the UT Southwestern Medical School maintains an on-line database containing all information from each ultrasound performed in the institution. This database was accessed to obtain the records of women who underwent sonograms which resulted in the diagnosis of isolated fetal MIVM from January 1, 1990 to February 28, 1996. From this database, 24 subjects were obtained for participation in the study. Two subjects were lost to attrition during data collection, resulting in a total of 22 clinical subjects. Comparison subjects were selected from the same on-line database. The criteria for inclusion in the comparison group was normal sonogram data, and uncomplicated pregnancy and birth. In addition, comparison subjects were selected to match the clinical subjects on the variables of age, sex, race, gestational age at birth and indication for the sonogram.

Data was collected in the spring of 1996. Study participants were administered the Bayley Scales of Infant Development - Second Edition (BSID-II) and the Vineland Adaptive Behavior Scales - Interview Edition, Short Form at a testing site at Parkland Memorial Hospital or St. Paul Hospital in Dallas, Texas. The instruments were administered by two doctoral students in school psychology who were blind as to the subject's membership in the clinical or comparison group.

Differences in the test scores of the clinical and comparison group were analyzed by conducting an ANCOVA, MANOVA, and a Fisher's exact test. A stepwise multiple regression was performed to determine which variables predicted a subject's membership in the clinical group. Finally, a discriminant analysis was conducted to determine if a subject's membership in the clinical or comparison group could be predicted from test scores. The results of the statistical analysis indicated that clinical subjects performed significantly lower on the Bayley Scales of Infant Development - Second Edition and demonstrated higher rates of developmental delay. However, the clinical and comparison groups were not found to differ in terms of their performance on the Vineland Adaptive Behavior Scales. MIMV status and race were significant predictors of the Mental Development Index of the BSID-II. Race, age, sex, and income level were significant predictors of the Composite on the Vineland. The MDI of the BSID-II predicted a subjects membership in the clinical versus comparison group while the Vineland Composite was not a significant predictor. Based on the results of this preliminary investigation, children with prenatally diagnosed MIVM demonstrate lower performance on a test of cognitive development and higher rates of developmental delay. Additional corroborative research is needed to provide the full clinical picture of fetal mild isolated ventriculomegaly.