Longitudinal pathways from prenatal alcohol exposure and infant behaviors to verbal IQ and working memory.

Objective

Assess infant behaviors as early predictors of Verbal IQ and Working Memory (V/WM) differences related to prenatal alcohol exposure (PAE) from 4 to 21 years of age. STUDY

Design

Longitudinal observational study of 387 infants (60% PAE; 48% male; 81% Black), from birth to 21 years. Verbal IQ or Working Memory was measured at 4, 9, 15, or 21yrs. with tests of intellectual functioning. Infants were administered a visual preference task and the Neurobehavioral Assessment (NB) at birth, the Fagan Test of Infant Intelligence (FTII) at 6.5 /12 mo. and Mental Development Index (MDI) of the Bayley Scales at 6.5, 12, 24 mos. Latent growth curve modeling assessed the association of PAE with V/WM over time, assessing infant behaviors as predictors.

Results

2-year Bayley MDI (Indirect effect (IE) = -0.11, SE = 0.045; p = 0.015) was linked to both PAE and V/WM. Abnormal NB correlated with V/WM (β = -0.21, p = 0.023; β = 0.23, p = 0.047, for intercept and slope, respectively). FTII at 6.5 months correlated with MDI (β = 0.16, p = 0.007) and FTII at 1 year (β=0.17, p = 0.005). Neonatal visual preference marginally correlated with FTII at 6.5 months (β = -0.13, p = 0.097). All relationships were controlled for other prenatal exposures, the home environment, and blood lead level.

Conclusions

PAE was related to poorer Verbal IQ and WM from 4 to 21 years of age, via 2-year cognitive outcomes associated with 6- and 12-month infant mental and visual recognition performance. Neonatal neurobehavioral abnormalities were related to V/WM independent of PAE. Infant assessments could aid early identification of cognitive sequelae of PAE in high-risk populations.