The interaction between diet and neurobehavior in very low birth weight infants.

BACKGROUND: Modulation of behavior and physiology by dietary perturbations early in life can provide clues to the pathogenesis of adult diseases. We tested the hypothesis that a period of early protein supplementation modulates sympathetic nervous system activity demonstrated indirectly by an increase in active sleep state distribution in very low birth weight (VLBW) infants. METHODS: VLBW infants (n = 71) were randomized to a total parenteral nutritional regimen providing 18% of the energy intake as amino acids (AA) or a conventional regimen providing 12.5% to achieve targeted AA intakes of 4 g/kg/day (0.004 kcal/kg/day) and 3 g/kg/day (0.003 kcal/kg/day), respectively. Both groups were weaned to enteral feeding and advanced to provide similar AA intake of 4 g/kg/day (0.004 kcal/kg/day). Six-hour daytime, behavioral sleep studies were performed when the infants reached full enteral intake (165 ml/kg/day). RESULTS: Infants in the high protein group spent more time in active sleep (77.2 ± 10.5% vs. 70.7 ± 11.8%), p < 0.01 and less time in quiet sleep (12.9 ± 3.4% vs. 17.7 ± 7.0%, p < 0.01) as compared to the conventional group. No group differences were observed for indeterminate sleep, awake, or crying states. CONCLUSIONS: These results suggest that dietary intake may indirectly influence sympathetic nervous system activity. IMPACT: Infants randomized to an early, high protein nutritional regimen spent an increased percentage of time in active sleep, supporting the hypothesis that nutrition and behavior are interactive. Furthermore, sleep states are an indirect measure of sympathetic nervous system activity, suggesting that dietary intake may influence sympathetic nervous system activity. This study highlights the importance of considering the impact of nutrition during critical periods of development in order to further understand and improve the long-term outcomes of very low birth weight infants.

Do dental students use optimal study strategies?

Research on human learning has shown that repeated retrieval practice or self-testing maximizes learning. However, recent studies have found undergraduate students to be largely unaware of the benefits of self-testing. The aim of this study was to examine dental students' study strategies and utilization of retrieval techniques for learning. All second-year dental students at New York University College of Dentistry were invited to participate. Of the total 360 students, 66 completed the two-question survey, for a response rate of 18.3%. The first question asked students to choose from a list of twelve study strategies the ones they used and to rank their top five in order of personal preference. Repeated reading was the most frequently used strategy with 83.3% of students reporting that they used it and 43.9% naming it as their top strategy. Of these students, 45.5% indicated that they self-tested while studying, but none indicated it was their number one strategy. The second question asked students how they would study after reading a textbook chapter for the first time. They were asked to choose one option from three possibilities: going back and restudying, self-testing (with the possibility of restudying afterward), or some other strategy. On this question, 25.8% chose restudying, 45.5% chose self-testing, and 28.8% indicated they would use another study strategy. Thus, 54.6% of the students reported they would not test themselves after reading a textbook chapter. Of those who chose self-testing, only seven students indicated they would do so to improve learning. The results of this study suggest that the students lacked sufficient awareness of the superiority of self-testing for learning.