Biological and environmental factors as predictors of language skills in very preterm children at 5 years of age.

OBJECTIVE: Language problems are thought to occur more frequently in very preterm children compared with healthy term born children. The primary aim of this study was to examine the contributions of biological and environmental risk factors to language outcomes in very preterm children at 5 years of age. METHODS: A cohort of 227 very preterm infants (birth weight <1250 g or gestational age <30 weeks) were recruited at birth and followed up at 2 and 5 years of age (corrected for prematurity) in a prospective, longitudinal study in Melbourne, Australia. Outcomes at 5 years of age were the Expressive and Receptive Language Scales from the Kaufman Survey of Early Academic and Language Skills. A range of hypothesized biological and environmental factors identified from past research were examined as predictors of language outcomes at 5 years of age using linear regression models. RESULTS: Lower maternal education and poorer communication skills in the child at 2 years of age were predictive of poorer expressive and poorer receptive language outcomes at 5 years of age. Lower expressive language scores were also associated with the presence of moderate-severe white matter abnormalities on neonatal magnetic resonance imaging. CONCLUSIONS: Results support the role of both biological and environmental factors in the evolution of language difficulties and highlight the need to consider these factors in the follow-up of preterm infants.

Language abilities in children who were very preterm and/or very low birth weight: a meta-analysis.

OBJECTIVE: To conduct a meta-analysis to characterize differences in language ability between children born very preterm (VPT, <32 weeks' gestational age), with a very low birth weight (VLBW, <1500 g), or both and in term-born control children. STUDY DESIGN: Electronic databases were systematically searched, and 12 studies met the inclusion criteria. Effect sizes were calculated to compare VPT/VLBW children and control children. RESULTS: VPT/VLBW children performed between 0.38 and 0.77 SD below control subjects in the areas of expressive and receptive language overall and expressive and receptive semantics. Results for expressive and receptive grammar were equivocal. Subgroup analysis of school-aged children revealed similar results. No studies assessing phonological awareness, discourse, or pragmatics were identified. CONCLUSIONS: Language ability is reduced in VPT/VLBW children. When considering only school-aged children, this reduction is still present, suggesting that their difficulty appears to be ongoing. Rigorous studies examining a range of language subdomains are needed to fully understand the specific nature of language difficulties in this population.

Rightward collisions and their association with pseudoneglect.

Whereas right parietal damage can result in left hemineglect, the general population shows a subtle neglect of the right hemispace-known as pseudoneglect. A recent study has demonstrated that people collide to the right more often and attributed this bias to pseudoneglect. [Nicholls, M. E. R., Loftus, A., Meyer, K., & Mattingley, J.B. (2007). Things that go bump in the right: The effect of unimanual activity on rightward collisions. Neuropsychologia, 45, 1122-1126]. Nicholls examined the effect of unimanual activation by requiring participants to fire projectiles at a target whilst walking and found that the rightward bias was exaggerated or reversed when the left and right hands were active, respectively. However, the act of aiming at a target may have inadvertently biased walking trajectory to the right. The current study addressed this issue by requiring participants (n=149) to walk through a narrow doorway three times whilst entering text into a phone using the (a) left, (b) right or (c) both hands. Despite the fact that entering text into a phone should produce no rightward bias, participants bumped to the right more often. Unlike previous research, no effect of unimanual activation was observed. This lack of effect was attributed to the smaller hand movements for entering numbers compared to firing a toy gun. Finally, this study showed an association for the first time between biases in observable bumping and line bisection performance-suggesting that unilateral bumping is related to pseudoneglect.

Human medial frontal cortex activity predicts learning from errors.

Learning from errors is a critical feature of human cognition. It underlies our ability to adapt to changing environmental demands and to tune behavior for optimal performance. The posterior medial frontal cortex (pMFC) has been implicated in the evaluation of errors to control behavior, although it has not previously been shown that activity in this region predicts learning from errors. Using functional magnetic resonance imaging, we examined activity in the pMFC during an associative learning task in which participants had to recall the spatial locations of 2-digit targets and were provided with immediate feedback regarding accuracy. Activity within the pMFC was significantly greater for errors that were subsequently corrected than for errors that were repeated. Moreover, pMFC activity during recall errors predicted future responses (correct vs. incorrect), despite a sizeable interval (on average 70 s) between an error and the next presentation of the same recall probe. Activity within the hippocampus also predicted future performance and correlated with error-feedback-related pMFC activity. A relationship between performance expectations and pMFC activity, in the absence of differing reinforcement value for errors, is consistent with the idea that error-related pMFC activity reflects the extent to which an outcome is "worse than expected."

Avoiding another mistake: error and posterror neural activity associated with adaptive posterror behavior change.

The magnitude of posterior medial frontal cortex (pMFC) activity during commission of an error has been shown to relate to adaptive posterror changes in response behavior on the trial immediately following. In the present article, we examined neural activity during and after error commission to identify its relationship to sustained posterror behavior changes that led to performance improvements several trials into the future. The standard task required participants to inhibit a prepotent motor response during infrequent lure trials, which were randomly interspersed among numerous go trials. Posterror behavior was manipulated by introducing a dynamic condition, in which an error on a lure trial ensured that the next lure would appear within two to seven go trials. Behavioral data indicated significantly higher levels of posterror slowing and accuracy during the dynamic condition, as well as fewer consecutive lure errors. Bilateral prefrontal cortex (PFC) and pMFC activity during the posterror period, but not during commission of the error itself, was associated with increased posterror slowing. Activity within two of these regions (right PFC and pMFC) also predicted success on the next lure trial. The findings support a relationship between pMFC/PFC activity and adaptive posterror behavior change, and the discrepancy between these findings and those of previous studies-in the present study, this relationship was detected during the posterror period rather than during commission of the error itself--may have resulted from the requirements of the present task. Implications of this discrepancy for the flexibility of cognitive control are discussed.