Executive and memory function in adolescents born very preterm

Maternal-preterm skin-to-skin contact enhances child physiologic organization and cognitive control across the first 10 years of life

BACKGROUND

Maternal-newborn contact enhances organization of the infant's physiological systems, including stress reactivity, autonomic functioning, and sleep patterns, and supports maturation of the prefrontal cortex and its ensuing effects on cognitive and behavioral control. Premature birth disrupts brain development and is associated with maternal separation and disturbances of contact-sensitive systems. However, it is unknown whether the provision of maternal-preterm contact can improve long-term functioning of these systems.

METHODS

We used the Kangaroo Care (KC) intervention and provided maternal-newborn skin-to-skin contact to 73 premature infants for 14 consecutive days compared with 73 case-matched control subjects receiving standard incubator care. Children were then followed seven times across the first decade of life and multiple physiologic, cognitive, parental mental health, and mother-child relational measures were assessed.

RESULTS

KC increased autonomic functioning (respiratory sinus arrhythmia, RSA) and maternal attachment behavior in the postpartum period, reduced maternal anxiety, and enhanced child cognitive development and executive functions from 6 months to 10 years. By 10 years of age, children receiving KC showed attenuated stress response, improved RSA, organized sleep, and better cognitive control. RSA and maternal behavior were dynamically interrelated over time, leading to improved physiology, executive functions, and mother-child reciprocity at 10 years.

CONCLUSIONS

These findings are the first to demonstrate long-term effects of early touch-based intervention on children's physiologic organization and behavioral control and have salient implications for the care practices of premature infants. Results demonstrate the dynamic cascades of child physiological regulation and parental provisions in shaping developmental outcome and may inform the construction of more targeted early interventions.

Regional white matter microstructure in very preterm infants: predictors and 7 year outcomes

The aims of this study were to investigate regional white matter microstructural differences between very preterm (VPT) (<30 weeks' gestational age and/or <1250 g) and full term (FT) (≥37 weeks' gestational age) infants at term corrected age with diffusion tensor imaging, and to explore perinatal predictors of diffusion measures, and the relationship between regional diffusion measures and neurodevelopmental outcomes at age 7 years in VPT children. Mean (MD) (p = .003), axial (AD) (p = .008), and radial diffusivity (RD) (p = .003) in total white matter were increased in VPT compared with FT infants, with similar fractional anisotropy (FA) in the two groups. There was little evidence that group-wise differences were specific to any of the 8 regions studied for each hemisphere. Perinatal white matter abnormality and intraventricular hemorrhage (grade III or IV) were associated with increased diffusivity in the white matter of VPT infants. Higher white matter diffusivity measures of the inferior occipital and cerebellar region at term-equivalent age were associated with increased risk of impairments in motor and executive function at 7 years in VPT children, but there was little evidence for associations with IQ or memory impairment. In conclusion, myelination is likely disrupted or delayed in VPT infants, especially those with perinatal brain abnormality (BA). Altered diffusivity at term-equivalent age helps explain impaired functioning at 7 years. This study defines the nature of microstructural alterations in VPT infant white matter, assists in understanding the associated risk factors, and is the first study to reveal an important link between inferior occipital and cerebellar white matter disorganization in infancy, and executive and motor functioning 7 years later.

Use of an eight-arm radial water maze to assess working and reference memory following neonatal brain injury

Working and reference memory are commonly assessed using the land based radial arm maze. However, this paradigm requires pretraining, food deprivation, and may introduce scent cue confounds. The eight-arm radial water maze is designed to evaluate reference and working memory performance simultaneously by requiring subjects to use extra-maze cues to locate escape platforms and remedies the limitations observed in land based radial arm maze designs. Specifically, subjects are required to avoid the arms previously used for escape during each testing day (working memory) as well as avoid the fixed arms, which never contain escape platforms (reference memory). Re-entries into arms that have already been used for escape during a testing session (and thus the escape platform has been removed) and re-entries into reference memory arms are indicative of working memory deficits. Alternatively, first entries into reference memory arms are indicative of reference memory deficits. We used this maze to compare performance of rats with neonatal brain injury and sham controls following induction of hypoxia-ischemia and show significant deficits in both working and reference memory after eleven days of testing. This protocol could be easily modified to examine many other models of learning impairment.

Candidate gene analysis: severe intraventricular hemorrhage in inborn preterm neonates

Intraventricular hemorrhage (IVH) is a disorder of complex etiology. We analyzed genotypes for 7 genes from 224 inborn preterm neonates treated with antenatal steroids and grade 3-4 IVH and 389 matched controls. Only methylenetetrahydrofolate reductase was more prevalent in cases of IVH, emphasizing the need for more comprehensive genetic strategies.

Behavioral and histological outcomes following neonatal HI injury in a preterm (P3) and term (P7) rodent model

Hypoxia-ischemia (HI) occurs when blood and/or oxygen delivery to the brain is compromised. HI injuries can occur in infants born prematurely (<37 weeks gestational age) or at very low birth weight (<1500 g), as well as in term infants with birth complications. In both preterm and term HI populations, brain injury is associated with subsequent behavioral deficits. Neonatal HI injury can be modeled in rodents (e.g., the Rice-Vannucci method, via cautery of right carotid followed by hypoxia). When this injury is induced early in life (between postnatal day (P)1-5), neuropathologies typical of human preterm HI are modeled. When injury is induced later (P7-12), neuropathologies typical of those seen in HI term infants are modeled. The current study sought to characterize the similarities/differences between outcomes following early (P3) and late (P7) HI injury in rats. Male rats with HI injury on P3 or P7, as well as sham controls, were tested on a variety of behavioral tasks in both juvenile and adult periods. Results showed that P7 HI rats displayed deficits on motor learning, rapid auditory processing (RAP), and other learning/memory tasks, as well as a reduction in volume in various neuroanatomical structures. P3 HI animals showed only transient deficits on RAP tasks in the juvenile period (but not in adulthood), yet robust deficits on a visual attention task in adulthood. P3 HI animals did not show any significant reductions in brain volume that we could detect. These data suggest that: (1) behavioral deficits following neonatal HI are task-specific depending on timing of injury; (2) P3 HI rats showed transient deficits on RAP tasks; (3) the more pervasive behavioral deficits seen following P7 HI injury were associated with substantial global tissue loss; and (4) persistent deficits in attention in P3 HI subjects might be linked to neural connectivity disturbances rather than a global loss of brain volume, given that no such pathology was found. These combined findings can be applied to our understanding of differing long-term outcomes following neonatal HI injury in premature versus term infants.

Outcomes of infants born at 22 and 23 weeks' gestation

OBJECTIVE

To provide instructive information on death and neurodevelopmental outcomes of infants born at 22 and 23 weeks' gestational age.

METHODS

The study cohort consisted of 1057 infants born at 22 to 25 weeks in the Neonatal Research Network, Japan. Neurodevelopmental impairment (NDI) at 36 to 42 months' chronological age was defined as any of the following: cerebral palsy, hearing impairment, visual impairment, and a developmental quotient <70. A systematic review was performed by using databases of publications of cohort studies with neonatal and neurodevelopmental outcomes at 22 and 23 weeks.

RESULTS

Numbers and incidences (%) of infants with death or NDI were 60 (80%) at 22 weeks and 156 (64%) at 23 weeks. In logistic regression analysis, gestational ages of 22 weeks (odds ratio [OR]: 5.40; 95% confidence interval [CI]: 2.48-11.76) and 23 weeks (OR: 2.14; 95% CI: 1.38-3.32) were associated with increased risk of death or NDI compared with 24 weeks, but a gestational age of 25 weeks (OR: 0.65; 95% CI: 0.45-0.95) was associated with decreased risk of death or NDI. In the systematic review, the medians (range) of the incidence of death or NDI in 8 cohorts were 99% (90%-100%) at 22 weeks and 98% (67%-100%) at 23 weeks.

CONCLUSIONS

Infants born at 22 and 23 weeks' gestation were at higher risk of death or NDI than infants at born at 24 weeks. However, outcomes were improved compared with those in previous studies. There is a need for additional discussions on interventions for infants born at 22 or 23 weeks' gestation.

Executive function outcome in preterm adolescents

Preterm birth (PT) and low birthweight (LBW) are risk factors for cognitive, academic, and behavioral difficulties. Executive functioning, which is an umbrella term encompassing higher-order problem-solving and goal-oriented abilities, may help to understand these impairments. This review article examines executive functioning in PT and LBW children, with a specific focus on adolescence and the functional consequences of executive dysfunction in this age group. We have focused on adolescence as it is a critical period for brain, cognitive and social-emotional development, and a period of increased autonomy, independence and reliance on executive functioning. While more longitudinal research is required, there is evidence demonstrating that the PT/LBW population is at increased risk for impairments across all executive domains. Emerging evidence also suggests that executive dysfunction may partly explain poorer academic and social-emotional competence in PT/LBW adolescents. In conclusion, PT/LBW adolescents exhibit poorer executive functioning, and close surveillance is recommended for high-risk individuals.

Preterm birth: neuropsychological profiles and atypical developmental pathways

Preterm birth is characterized by multiple interacting atypical constraints affecting different aspects of neuropsychological development. In the first years of life, perceptual, motor, and communicative-linguistic abilities, as well as attention, processing speed, and memory are affected by preterm birth resulting in cascading effects on later development. From school age to adolescence, a catch-up of simpler competencies (i.e., receptive lexicon) along with a more selective effect on more complex competencies (i.e., complex linguistic functions, math, motor, and executive functions) are observed, as well as a relevant incidence of behavioral outcomes. A wide heterogeneity in preterm children's neuropsychological profiles is described depending on the interaction among the degree of neonatal immaturity, medical complications, neurological damages/alterations, environmental and social factors. Severe neuromotor and sensory damages are not frequent, while low severity impairments are common among preterm children. It is argued that developmental pathways of preterm children are atypical, and not merely delayed, and are characterized by different developmental patterns and relationships among competencies.

Therapeutic effect of caffeine treatment immediately following neonatal hypoxic-ischemic injury on spatial memory in male rats

Hypoxia Ischemia (HI) refers to the disruption of blood and/or oxygen delivery to the brain. Term infants suffering perinatal complications that result in decreased blood flow and/or oxygen delivery to the brain are at risk for HI. Among a variety of developmental delays in this population, HI injured infants demonstrate subsequent memory deficits. The Rice-Vannucci rodent HI model can be used to explore behavioral deficits following early HI events, as well as possible therapeutic agents to help reduce deleterious outcomes. Caffeine is an adenosine receptor antagonist that has recently shown promising results as a therapeutic agent following HI injury. The current study sought to investigate the therapeutic benefit of caffeine following early HI injury in male rats. On post-natal day (P) 7, HI injury was induced (cauterization of the right common carotid artery, followed by two hours of 8% oxygen). Male sham animals received only a midline incision with no manipulation of the artery followed by room air exposure for two hours. Subsets of HI and sham animals then received either an intraperitoneal (i.p.) injection of caffeine (10 mg/kg), or vehicle (sterile saline) immediately following hypoxia. All animals later underwent testing on the Morris Water Maze (MWM) from P90 to P95. Results show that HI injured animals (with no caffeine treatment) displayed significant deficits on the MWM task relative to shams. These deficits were attenuated by caffeine treatment when given immediately following the induction of HI. We also found a reduction in right cortical volume (ipsilateral to injury) in HI saline animals as compared to shams, while right cortical volume in the HI caffeine treated animals was intermediate. These findings suggest that caffeine is a potential therapeutic agent that could be used in HI injured infants to reduce brain injury and preserve subsequent cognitive function.

Neonatal and parental predictors of executive function in very preterm children

AIM

To examine neonatal and parental predictors of executive function in very preterm (gestational age ≤30 weeks) children aged 4.0-12.0 years.

METHODS

Two-hundred very preterm (mean age 8.2 ± 2.5 years) children without severe disabilities, born between 1996 and 2004, were assessed with measures of executive function including working memory, verbal fluency, planning and inhibitory control. Neonatal predictors were obtained from clinical records. Parental predictors included parental education, which was derived from questionnaires. Multiple linear regression analyses identified associations between neonatal and parental predictors and executive function in very preterm children.

RESULTS

Better postnatal growth at 6 weeks of corrected age-predicted better spatial span (R² = 0.03, β = 0.17, p = 0.02) and planning (R² = 0.03, β = 0.16, p = 0.04). A higher level of parental education predicted better verbal fluency (R² = 0.02, β = 0.12, p = 0.02). Verbal working memory was not predicted by neonatal risk factors or by parental education (β(s ) < 0.09, p(s ) > 0.20).

CONCLUSIONS

Executive function in very preterm children is associated with early postnatal growth and level of parental education but not with neonatal complications.

Self- and parent-rated executive functioning in young adults with very low birth weight

BACKGROUND AND OBJECTIVE

Adults born preterm score lower on performance-based tests of executive functioning (EF) than their term-born peers. These test scores do not necessarily translate to application of these skills in an everyday environment. The objective of the study was to test differences between very low birth weight (VLBW; <1500 g) adults and their term-born peers in self- and parent-rated EF and examine concordance between self- and parent-rated EF and performance-based tests of EF.

METHODS

A longitudinal study of 90 VLBW adults and 93 term-born controls (aged 21-30 years) was performed. The young adults and their parents filled in the Behavioral Rating Inventory of Executive Functioning-Adult Version, and the adults underwent performance-based tests of EF.

RESULTS

VLBW young adults and especially those born appropriate for gestational age reported fewer problems in behavioral regulation and global EF than term-born controls; however, parents of VLBW adults born small for gestational age reported more problems for their children in all EF scales than parents of the controls. Compared with their parents, VLBW young adults reported fewer problems in behavioral regulation. Adults' ratings and their parents' ratings correlated significantly among VLBW and control groups. In the VLBW and VLBW/small-for-gestational-age groups, parent ratings of EF were correlated to performance-based tests, whereas among term-born adults, self-reports correlated.

CONCLUSIONS

These findings reveal that VLBW adults may have learned to compensate in the everyday environment for their EF deficits apparent in performance-based tests. Alternatively, VLBW adults may have positively skewed views of their abilities.

Effect of infant prematurity on auditory brainstem response at preschool age

INTRODUCTION

Preterm birth is a risk factor for a number of conditions that requires comprehensive examination. Our study was designed to investigate the impact of preterm birth on the processing of auditory stimuli and brain structures at the brainstem level at a preschool age.

MATERIALS AND METHODS

An auditory brainstem response (ABR) test was performed with low rates of stimuli in 60 children aged 4 to 6 years. Thirty subjects had been born following a very preterm labor or late-preterm labor and 30 control subjects had been born following a full-term labor.

RESULTS

Significant differences in the ABR test result were observed in terms of the inter-peak intervals of the I-III and III-V waves, and the absolute latency of the III wave (P<0.019). No significant differences were observed in the amplitude of the I or V waves. The choice of test ear examined had no effect on the results.

CONCLUSION

Our results indicate an effect of preterm birth on ABRs and synchronization of auditory stimuli at preschool age, and suggest the need for further follow-up over the coming years.

Does neonatal morphine use affect neuropsychological outcomes at 8 to 9 years of age?

Morphine is widely used to treat severe pain in neonatal intensive care unit patients. Animal studies suggest adverse long-term side effects of neonatal morphine, but a follow-up study of 5-year-old children who participated in a morphine-placebo controlled trial as newborns found no such effects on the child's general functioning. This study indicated that morphine may negatively affect response inhibition, a domain of executive functions. Therefore, we performed a second follow-up study in the same population at the age of 8 to 9 years, focused on the child's general functioning in terms of intelligence, visual motor integration, and behavior and on executive functions. Children in the morphine group showed significantly less externalizing problems according to the parents but more internalizing behavior according to the teachers, but only after adjustment for intelligence quotient (IQ), potential confounders using a propensity score, and additional open-label morphine. Morphine-treated children showed significantly fewer problems with executive functions in daily life as rated by parents for the subscales inhibition and organization of materials and for planning/organizing as rated by the teachers. After adjustment for IQ and the propensity score, executive functioning as rated by the parents remained statistically significantly better in the morphine-treated group. The influence of the additional morphine given was not of a significant influence for any of the outcome variables. Overall, the present study demonstrates that continuous morphine infusion of 10 μg/kg/h during the neonatal period does not harm general functioning and may even have a positive influence on executive functions at 8 to 9 years.

Academic achievement of adolescents born with extremely low birth weight

AIM

To assess academic achievement, rates of learning disabilities (LD) and special education in extremely low birth weight (ELBW <1 kg) adolescents relative to normal birth weight (NBW) controls and to identify cognitive weaknesses.

METHODS

Compared 181 ELBW adolescents born from 1992 to 1995 (mean age 14.8 years, mean BW 809 g, mean GA 26.4 weeks) and 115 NBW term controls. Measures included tests of IQ, reading and math achievement and executive function. Analyses included ANCOVA and logistic and linear regression. Covariates were sex, race and socioeconomic status.

RESULTS

Extremely low birth weight adolescents had significantly lower scores on tests of IQ (87.1 vs. 96.4), achievement (88.6 vs. 95.5 reading; 81.3 vs. 93.2 math) and executive function than the NBW group (all p-values <0.001). ELBW also had higher rates of math LD, 51(50%) vs. 26 (28%), OR (95% CI) = 3.10 (1.65, 5.84), p < 0.001, and need for special education, 88 (49%) vs. 11(10%), OR (95% CI) = 11.78 (5.67, 24.47), p < 0.001. Measures of executive function were related to math independent of IQ.

CONCLUSIONS

Extremely low birth weight adolescents born in the 1990s have poorer achievement and higher rates of math LD than NBW peers. The findings suggest a need for more intensive interventions addressing the specific cognitive vulnerabilities in this population.

Neurodevelopmental impairment following neonatal hyperoxia in the mouse

Extremely premature infants are often exposed to supra-physiologic concentrations of oxygen, and frequently have hypoxemic episodes. These preterm infants are at high risk (~40%) for neurodevelopmental impairment (NDI) even in the absence of obvious intracranial pathology such as intraventricular hemorrhage or periventricular leukomalacia. The etiology for NDI has not been determined, and there are no animal models to simulate neurodevelopmental outcomes of prematurity. Our objectives were to develop and characterize a mouse model to determine long-term effects of chronic hypoxia or hyperoxia exposure on neurodevelopment. Newborn C57BL/6 mice were exposed to hypoxia (12% O(2)) or hyperoxia (85% O(2)) from postnatal days 1 to 14 and then returned to air. At 12-14 weeks of age, neurobehavioral assessment (Water Maze test, Novel Object Recognition test, Open Field test, Elevated Plus Maze, and Rotarod test) was performed, followed by MRI and brain histology. Neurobehavioral testing revealed that hyperoxia-exposed mice did poorly on the water maze and novel object recognition tests compared to air-exposed mice. MRI demonstrated smaller hippocampi in hyperoxia- and hypoxia-exposed mice with a greater reduction in hyperoxia-exposed mice, including a smaller cerebellum in hyperoxia-exposed mice. Brain histology showed reduced CA1 and CA3 and increased dentate gyral width in hippocampus. In conclusion, neonatal hyperoxia in mice leads to abnormal neurobehavior, primarily deficits in spatial and recognition memory, associated with smaller hippocampal sizes, similar to findings in ex-preterm infants. This animal model may be useful to determine mechanisms underlying developmental programming of NDI in preterm infants, and for evaluation of therapeutic strategies.

Oculomotor assessments of executive function in preterm children

OBJECTIVE

To use objective, nonverbal oculomotor tasks to assess executive function and infer the neural basis of impairments in preterm children.

STUDY DESIGN

Cross-sectional study of preterm children age 9-16 years (n = 69; mean gestational age 29 weeks) and full-term controls (n = 43). Tasks assessed sensorimotor function (reflexive prosaccades); resistance to peripheral distracters (fixation); response inhibition, response preparation, and execution of a voluntary saccade (antisaccades); and spatial working memory (memory-guided saccades). Group differences were analyzed using ANOVA. We used linear regression to analyze the contributions of age, sex, gestational age, and white matter category to task performance.

RESULTS

Preterm children did not differ from controls on basic sensorimotor function, response inhibition, and working memory. Compared with controls, preterm children showed greater susceptibility to peripheral distracters (P = .008) and were slower to initiate an inhibitory response (P = .003). Regression models showed contributions of age and white matter category to task performance.

CONCLUSIONS

Preterm children show intact basic sensorimotor function and demonstrate difficulties in processes underlying executive control, including increased distractibility and prolonged response preparation. These limitations may reflect specific neural abnormalities in fronto-subcortical executive control of behavior.

Behavior disorders in extremely preterm/extremely low birth weight children in kindergarten

OBJECTIVE

To examine the prevalence of behavior disorders in a 2001-2003 birth cohort of extremely preterm/extremely low birth weight (EPT/ELBW, <28 weeks gestational age or <1000 g) children in kindergarten.

METHOD

We compared 148 EPT/ELBW children with 111 term-born normal birth weight classmate controls on reports of psychiatric symptoms obtained from parent interview (Children's Interview for Psychiatric Syndromes-Parent Form [P-ChIPS]), parent and teacher ratings of behavior (Child Behavior Checklist, Teacher's Report Form, and Behavior Rating Inventory of Executive Function), and teacher ratings of social functioning (School Social Behavior Scales, second edition). Associations of behavior disorders with global cognitive ability and tests of executive function were also examined within the EPT/ELBW group.

RESULTS

Rates of attention-deficit/hyperactivity disorder combined on psychiatric interview were about twice as high for the EPT/ELBW group than for the normal birth weight group, odds ratio (95% confidence interval) = 2.50 (1.34, 4.68), p = .004. The EPT/ELBW group also had much higher rates of teacher-identified disorders in attention, behavior self-regulation, and social functioning, with odds ratios (95% confidence intervals) ranging from 3.35 (1.64, 6.83) to 18.03 (4.12, 78.94), all p values <.01. Attention-deficit/hyperactivity disorder and impaired behavior self-regulation were associated with deficits on tests of executive function but not with global cognitive impairment.

CONCLUSIONS

The findings document increased rates of disorders in attention, behavior self-regulation, and socialization in EPT/ELBW children and suggest that deficits on tests of executive function are associated with some of these disorders. Early identification and intervention for these disorders are needed to promote early adjustment to school and facilitate learning progress.

Clinical importance of hypothyroxinemia in the preterm infant and a discussion of treatment concerns

PURPOSE OF REVIEW

Survival for the extremely low gestational age neonate (ELGAN; 24-28 weeks) has risen to more than 80%. This extraordinary achievement is tempered by the persistence of cognitive delays and cerebral palsy (CP) affecting nearly one in eight survivors, and requiring subsequent rehabilitative services. A major priority in newborn medicine must be to translate the gains in survival achieved over the past 40 years into gains in healthy survival without the current high frequency of impairments.

RECENT FINDINGS

Transient hypothyroxinemia in ELGANs is strongly associated with lower IQ scores, behavioral abnormalities and CP. Limited evidence suggests the possibility of a benefit from hormone replacement therapy, but the optimal trial has yet to be conducted. A continuous infusion of 4 μg/kg per day thyroxine for 42 days can safely correct transient hypothyroxinemia without markedly lowering thyroid stimulating hormone levels, thus creating a biochemical euthyroid state. Whether this treatment will make an impact on long-term outcomes is not yet known.

SUMMARY

With 25 000 neonates born in less than 28 weeks each year in the USA, the economic impact of the very high rates of cognitive disabilities and related neurological dysfunction in survivors is substantial. The lifetime direct and indirect costs of CP are estimated at US$1 million per person and the costs of mental retardation are even higher. If reversal of transient hypothyroxinemia proves effective in reducing the risks of CP or mental retardation in ELGANs by 30%, we estimate an overall saving of US$ 3 billion per year. There is a pressing need for a phase III trial of thyroid hormone that is of sufficient duration and size to determine whether a clinically important reduction in risk of developmental impairments in ELGANs can be achieved.

Memory processes in learning disability subtypes of children born preterm

The purpose of this study was to evaluate immediate auditory and visual memory processes in learning disability subtypes of 40 children born preterm. Three subgroups of children were examined: (a) primary language disability group (n = 13), (b) perceptual-motor disability group (n = 14), and (c) no learning disability diagnosis group without identified language or perceptual-motor learning disability (n = 13). Between-group comparisons indicate no significant differences in immediate auditory or visual memory performances between language and perceptual-motor learning disability groups. Within-group comparisons revealed that both learning disability groups performed significantly lower on a task of immediate memory when the mode of stimulus presentation and mode of response were visual.

Motor learning and working memory in children born preterm: a systematic review

Children born preterm have a higher risk for developing motor, cognitive, and behavioral problems. Motor problems can occur in combination with working memory problems, and working memory is important for explicit learning of motor skills. The relation between motor learning and working memory has never been reviewed. The goal of this review was to provide an overview of motor learning, visual working memory and the role of working memory on motor learning in preterm children. A systematic review conducted in four databases identified 38 relevant articles, which were evaluated for methodological quality. Only 4 of 38 articles discussed motor learning in preterm children. Thirty-four studies reported on visual working memory; preterm birth affected performance on visual working memory tests. Information regarding motor learning and the role of working memory on the different components of motor learning was not available. Future research should address this issue. Insight in the relation between motor learning and visual working memory may contribute to the development of evidence based intervention programs for children born preterm.

Executive function skills are associated with reading and parent-rated child function in children born prematurely

BACKGROUND

Preterm children are at risk for executive function (EF) problems, which have been linked to behavior and learning problems in full term children. In this study, we examine the relationship between EF and functional outcomes in preterm children.

AIM

To evaluate (1) EF skills of 9- to 16-year-old children born across the spectrum of gestational age (GA), (2) relationship of degree of prematurity to EF skills, and (3) contributions of EF skills to two functional outcomes - reading scores and parent-rated child function.

METHOD

Preterm children <36 weeks gestation (n=72) were compared to full term children (n=42) of similar age, gender and SES, on measures of EF, reading, and parent-ratings of child function. Multiple regression models evaluated contributions to EF skills and functional outcomes.

RESULTS

Compared to full term controls, preterm children had poorer EF performance on a complex planning and organization task and did not increase planning time as task difficulty increased. Their spatial memory capacity was not different. GA contributed to EF skills, but was mediated by IQ. EF contributed to the variance in reading skills but did not add to the variance in reading when IQ was considered. EF skills significantly contributed to the variance in parent-rated child function, but IQ did not.

CONCLUSION

EF skills contribute to measures of functional outcome in this high-risk population. The use of EF skills as an early marker for learning and functional problems and as a target for intervention in children born preterm warrants future study.

Outcomes of preterm infants: morbidity replaces mortality

Over the last 50 years in the United States a rising preterm birth rate, a progressive decrease in preterm mortality, and a lowering of the limit of viability have made preterm birth a significant public health problem. Neuromaturation, the functional development of the central nervous system (CNS), is a dynamic process that promotes and shapes CNS structural development. This article reviews preterm outcomes, recognizing that multiple factors influence neuromaturation and lead to a range of neurodevelopmental disabilities, dysfunctions, and altered CNS processing. Ways to protect preterm infants and support their growth and development in and beyond intensive care are examined.