Cognitive and motor function of neurologically impaired extremely low birth weight children.

BACKGROUND: Rates of neurological impairment among extremely low birth weight children (ELBW [<1 kg]) have decreased since 2000; however, their functioning is unexamined. OBJECTIVE: To compare motor and cognitive functioning of ELBW children with neurological impairment, including cerebral palsy and severe hypotonia/hypertonia, between two periods: 1990 to 1999 (n=83) and 2000 to 2005 (n=34). METHODS: Measures of function at 20 months corrected age included the Mental and Psychomotor Developmental Indexes of the Bayley Scales of Infant Development and the Gross Motor Functional Classification System as primary outcomes and individual motor function items as secondary outcomes. RESULTS: Analysis failed to reveal significant differences for the primary outcomes, although during 2000 to 2005, sitting significantly improved in children with neurological impairment (P=0.003). CONCLUSION: Decreases in rates of neurological impairment among ELBW children have been accompanied by a suggestion of improved motor function, although cognitive function has not changed.

HISTORIQUE: Les taux d'atteinte neurologique chez les enfants d'extrême petit poids à la naissance (EPPN [<1 kg]) ont diminué depuis 2000. Cependant, le fonctionnement de ces enfants n'a pas fait l'objet d'examens. OBJECTIF: Comparer le fonctionnement moteur et cognitif des enfants d'EPPN ayant une atteinte neurologique, y compris la paralysie cérébrale et l'hypotonie et l'hypertonie graves, pendant deux périodes : de 1990 à 1999 (n=83) et de 2000 à 2005 (n=34). MÉTHODOLOGIE: Les mesures de la fonction à 20 mois d'âge corrigé incluaient les résultats cliniques primaires grâce aux indices de développement mental et psychomoteur de l'échelle Bayley du développement des nourrissons et au système de classification de la motricité brute, et les résultats cliniques secondaires grâce aux éléments de la fonction motrice individuelle. RÉSULTATS: L'analyse n'a pu révéler de différences significatives dans les résultats cliniques primaires, même si entre 2000 et 2005, la position assise s'est considérablement améliorée chez les enfants ayant une atteinte neurologique (P=0,003). CONCLUSION: La diminution des taux d'atteinte neurologique chez les enfants d'EPPN s'accompagne de la suggestion d'une amélioration de la fonction motrice, même si la fonction cognitive n'a pas changé.

Delivering perinatal psychiatric services in the neonatal intensive care unit.

AIM: To describe characteristics of mothers who would likely benefit from on-site short-term psychiatric services while their infant is in the neonatal intensive care unit (NICU). METHODS: For 150 consecutive mothers who were referred for psychiatric evaluation and psychotherapeutic intervention in an innovative NICU mental health programme, baseline information was collected. Data regarding their referrals, diagnosis, treatments and infants were analysed. RESULTS: Most mothers were referred because of depression (43%), anxiety (44%) and/or difficulty coping with their infant's medical problems and hospitalization (60%). Mothers of VLBW infants were disproportionately more likely to be referred. A majority of mothers accepted the referral and were treated; most only required short-term psychotherapy. A minority resisted or refused psychiatric assessment; a quarter of these had more difficult interactions with staff or inappropriate behaviours. In these cases, the role of the psychiatrist was to work with staff to promote healthy interactions and to foster maternal-infant bonding. CONCLUSION: Overall, on-site psychiatric services have been accepted by a majority of referred NICU mothers, and most did not require long-term treatment. A considerable need exists for psychiatric services in the NICU to promote optimal parenting and interactions.

Fetal irradiation interferes with adult cognition in the nonhuman primate.

BACKGROUND: Exposure to x-irradiation in early gestation has been shown to disrupt normal thalamocortical development in the monkey and thereby model one key feature of the neuropathology of schizophrenia. However, the effect of fetal irradiation on cognitive functions that are vulnerable in schizophrenia (e.g., working memory) has not been examined. METHODS: Four fetally irradiated macaque monkeys (FIMs) and four age-matched controls (CONs) were tested as juveniles (12-30 months) and again as adults ( approximately 5 years) on delayed spatial response (DR), a working memory task that is dependent on intact prefrontal cortical circuitry. RESULTS: As juveniles, seven of eight monkeys learned DR; one FIM refused to test. Performance in the two groups was not different. As adults, only one FIM achieved criterion on DR. Three of four FIMs did not reach criterion at the 0-sec delay interval of the DR task, whereas all four CONs mastered DR at the maximum tested delay of 10 sec. FIMs completed fewer DR test sessions compared with CONs. In contrast, all FIMs and three of four CONs learned an associative memory task, visual pattern discrimination. CONCLUSIONS: Fetal exposure to irradiation resulted in an adult-onset cognitive impairment in the working memory domain that is relevant to understanding the developmental etiology of schizophrenia.

Outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia: effects of practice changes in 2000 to 2003.

OBJECTIVE: The goal was to evaluate whether changes in neonatal intensive care have improved outcomes for children with bronchopulmonary dysplasia (oxygen dependence at corrected age of 36 weeks). METHODS: We compared outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia between 2 periods (period I, 1996-1999: extremely low birth weight, n = 122; extremely low gestational age, n = 118; period II, 2000-2003: extremely low birth weight, n = 109; extremely low gestational age, n = 107). RESULTS: For both groups, significant practice changes between period I and period II included increased prenatal and decreased postnatal steroid therapy and increased surfactant therapy, indomethacin therapy, and patent ductus arteriosus ligation. Significant morbidity changes included decreased rates of severe cranial ultrasound abnormalities and increased rates of ventilator dependence. Rates of bronchopulmonary dysplasia did not change (52% vs 53%). Follow-up evaluation revealed significantly lower rates of neurosensory abnormalities during period II (extremely low birth weight: 29% vs 16%; extremely low gestational age: 31% vs 16%). There were no changes in rates of Mental Developmental Index scores of <70 (extremely low birth weight: 42% vs 42%; extremely low gestational age: 37% vs 45%) or overall developmental impairment (extremely low birth weight: 51% vs 49%; extremely low gestational age: 50% vs 51%). For the extremely low gestational age group, predictors of neurosensory abnormalities were severe cranial ultrasound abnormality and postnatal steroid therapy. Predictors of overall impairment included severe cranial ultrasound abnormalities, ventilator dependence, postnatal steroid therapy, and patent ductus arteriosus ligation. For the extremely low birth weight group, the only predictor of neurosensory abnormalities was severe cranial ultrasound abnormality. Predictors of overall impairment included multiple birth, ventilator dependence, and severe cranial ultrasound abnormalities. CONCLUSIONS: Neurosensory outcomes of infants with bronchopulmonary dysplasia improved during 2000 to 2003 but overall neurodevelopmental outcomes did not change.

Improved neurodevelopmental outcomes for extremely low birth weight infants in 2000-2002.

BACKGROUND: Neurodevelopmental impairment of extremely low birth weight infants increased in the 1990s. Modern therapeutic changes may have influenced more recent neonatal outcomes. OBJECTIVE: We sought to compare neonatal therapies and outcomes among all extremely low birth weight infants born in 2000-2002 (period III) to 2 previous periods: 1982-1989 (period I) and 1990-1999 (period II). METHODS: The population included 496 extremely low birth weight infants born at our perinatal center during period I, 749 during period II, and 233 during period III. Therapies, rates of death, and survival with and without impairment at 20 months' corrected age were compared. RESULTS: Between periods I and II, survival increased from 49% to 68% as did neonatal morbidity. This resulted in increased survival without impairment but also increased survival with impairment. Changes in therapy during period III included an increase in antenatal steroid use and a decrease in postnatal steroid use, although the rate of chronic lung disease did not change. Sepsis decreased, as did severe intraventricular hemorrhage. On follow-up, the rate of cerebral palsy decreased from 13% to 5%, resulting in a decrease in neurodevelopmental impairment from 35% to 23%. As a result, during period III versus II, survival without impairment increased, whereas survival with impairment decreased. CONCLUSION: Since 2000, neurodevelopmental impairment has decreased among extremely low birth weight infants. A variety of perinatal and neonatal factors were associated with the improved outcomes including increased antenatal steroid use and cesarean section delivery, as well as decreased sepsis, severe cranial ultrasound abnormalities, and postnatal steroid use despite no change in the rate of chronic lung disease.

Postdischarge growth failure among extremely low birth weight infants: Correlates and consequences.

OBJECTIVE: To describe the prevalence and correlates of postdis-charge growth failure among extremely low birth weight (ELBW) infants (weighing less than 1 kg) and its impact on growth and development. METHODS: One hundred fifty-four ELBW infants were followed to 20 months corrected age. Growth failure was defined as a decrease in weight z score (standard deviation score) of over 0.67 during one of three periods: between 40 weeks and four months (period I), between four and eight months (period II), and between eight and 20 months corrected age (period III). A decrease in weight z score of this magnitude is comparable to crossing major growth percentiles (eg, from 25th to 10th percentile). Developmental outcomes were assessed at 20 months. RESULTS: Growth failure occurred in 8% of infants during period I, 28% during period II and 12% during period III. This resulted in poorer growth attainment and motor function at 20 months. Significant predictors of growth failure included chronic lung disease during periods I and III, and cerebral palsy during period III. Growth failure during period II, while more common, was not associated with specific sequelae of prematurity. It may represent a physiological process comparable to shifts in weight percentiles in term-born infants. CONCLUSIONS: Postdischarge growth failure is common among ELBW infants and contributes to poorer growth outcomes. It is associated with poorer motor outcomes when it occurs early after discharge or later in infancy. A decrease in weight z score of over 0.67 can serve as a useful indicator of growth failure in ELBW infants.

Poor predictive validity of the Bayley Scales of Infant Development for cognitive function of extremely low birth weight children at school age.

OBJECTIVE: The Bayley Scales of Infant Development, Second Edition (BSID II) are commonly used to assess outcomes of extremely low birth weight (ELBW) infants. We sought to assess the predictive validity of the BSID II Mental Developmental Index (MDI) for cognitive function at school age. DESIGN/METHODS: Of 330 ELBW infants admitted in 1992-1995, 238 (72%) survived to the age of 8 years, of whom 200 (84%) were tested at both 20 months' corrected age (CA) and 8 years. Mean birth weight was 811 g, mean gestational age was 26.4 weeks, 41% were boys, and 60% were black. Measures included the BSID II at 20 months' CA and the Kaufman Assessment Battery for Children (KABC) Mental Processing Composite (MPC) at 8 years' postnatal age. BSID II MDI and MPC scores were compared and the predictive validity calculated for all 200 ELBW children and for the 154 ELBW neurosensory-intact subgroup. Predictors of stability or change in cognitive scores were examined via logistic regression adjusting for gender and sociodemographic status. RESULTS: For all ELBW children, the mean MDI was 75.6 +/- 16 versus a mean KABC of 87.8 +/- 19. For the neurosensory-intact subgroup, the mean MDI was 79.3 +/- 16 and the mean KABC was 92.3 +/- 15. Rates of cognitive impairment, defined as an MDI or KABC of <70, dropped from 39% at 20 months' CA to 16% at 8 years for the total ELBW population and from 29% to 7% for the neurosensory-intact subgroup. The positive predictive value of having an MPC of <70 given an MDI of <70 was 0.37 (95% confidence interval [CI]: 0.27, 0.49) for all ELBW infants, 0.20 (95% CI: 0.10, 0.35) for the neurosensory-intact subgroup, and 0.61 (95% CI: 0.42, 0.77) for the neurosensory-impaired subgroup. The negative predictive values were 0.98, 0.99, and 0.85 for the 3 groups, respectively. Neurosensory impairment at 20 months' CA predicted lack of improvement of cognitive function (odds ratio: 6.9; 95% CI: 2.4, 20.2). Children whose cognitive scores improved between 20 months and 8 years had significantly better school performance than those whose scores stayed at <70, but they did less well than those whose scores were persistently >70. CONCLUSIONS: The predictive validity of a subnormal MDI for cognitive function at school age is poor but better for ELBW children who have neurosensory impairments. We are concerned that decisions to provide intensive care for ELBW infants in the delivery room might be biased by reported high rates of cognitive impairments based on the use and presumptive validity of the BSID II MDI.

Cortical afferents to the smooth-pursuit region of the macaque monkey's frontal eye field.

In primates, the frontal eye field (FEF) contains separate representations of saccadic and smooth-pursuit eye movements. The smooth-pursuit region (FEFsem) in macaque monkeys lies principally in the fundus and deep posterior wall of the arcuate sulcus, between the FEF saccade region (FEFsac) in the anterior wall and somatomotor areas on the posterior wall and convexity. In this study, cortical afferents to FEFsem were mapped by injecting retrograde tracers (WGA-HRP and fast blue) into electrophysiologically identified FEFsem sites in two monkeys. In the frontal lobe, labeled neurons were found mostly on the ipsilateral side in the (1) supplementary eye field region and lateral area F7; (2) area F2 along the superior limb of the arcuate sulcus; and (3) in the buried cortex of the arcuate sulcus extending along the superior and inferior limbs and including FEFsac and adjacent areas 8, 45, and PMv. Labeled cells were also found in the caudal periprincipal cortex (area 46) in one monkey. Labeled cells were found bilaterally in the frontal lobe in the deep posterior walls of the arcuate sulcus and postarcuate spurs and in cingulate motor areas 24 and 24c. In postcentral cortical areas all labeling was ipsilateral and there were two major foci of labeled cells: (1) the depths of the intraparietal sulcus including areas VIP, LIP, and PEa, and (2) the anterior wall and fundus of the superior temporal sulcus including areas PP and MST. Smaller numbers of labeled cells were found in superior temporal sulcal areas FST, MT, and STP, posterior cingulate area 23b, area 3a within the central sulcus, areas SII, RI, Tpt in the lateral sulcus, and parietal areas 7a, 7b, PEc, MIP, DP, and V3A. Many of these posterior afferent cortical areas code visual-motion (MT, MST, and FST) or visual-motion and vestibular (PP, VIP) signals, consistent with the responses of neurons in FEFsem and with the overall physiology and anatomy of the smooth-pursuit eye movement system.

Improved survival rates with increased neurodevelopmental disability for extremely low birth weight infants in the 1990s.

BACKGROUND: Advances in perinatal care have resulted in increased survival rates for extremely low birth weight children. We sought to examine the relative changes in rates of survival and neurodevelopmental impairment at 20 months of corrected age among 500- to 999-g birth weight infants born at our perinatal center during 2 periods, before and after the introduction of surfactant therapy in 1990. METHODS: Four hundred ninety-six infants with birth weights of 500 to 999 g were born at our perinatal center during period I (1982-1989) (mean body weight: 762 g; mean gestational age: 25.8 weeks) and 682 during period II (1990-1998) (mean body weight: 756 g; mean gestational age: 25.5 weeks). Rates of death and survival with and without neurodevelopmental impairment at 20 months of corrected age for the 2 periods were compared with logistic regression analyses, with adjustment for gestational age. RESULTS: Survival rates increased from 49% during period I to 67% during period II. Neonatal morbidity rates also increased during period II, including rates of sepsis (from 37% to 51%), periventricular leukomalacia (from 2% to 7%), and chronic lung disease, defined as oxygen dependence at 36 weeks of corrected age (from 32% to 43%). Rates of severe cranial ultrasound abnormalities were similar (22% vs 22%). Among children monitored, the rate of neurologic abnormalities, including cerebral palsy, increased from 16% during period I to 25% during period II and the rate of deafness increased from 3% to 7%. The overall rate of neurodevelopmental impairment (major neurosensory abnormality and/or Bayley Mental Developmental Index score of <70) increased from 26% to 36%. Compared with period I, in period II there were decreased rates of death (odds ratio [OR]: 0.3; 95% confidence interval [CI]: 0.2-0.4) and increased rates of survival with impairment (OR: 2.3; 95% CI: 1.7-3.3) but also increased rates of survival without impairment (OR: 1.7; 95% CI: 1.3-2.2). Compared with period I, for every 100 infants with birth weights of 500 to 999 g born in period II, 18 additional infants survived, of whom 7 were unimpaired and 11 were impaired. CONCLUSIONS: The improved survival rates in the 1990s occurred with an increased risk of significant neurodevelopmental impairment. Prospective parents of extremely low birth weight infants should be advised of this substantial risk, to facilitate decision-making in the delivery room.

The effect of neonatal maternal milk feeding on the neurodevelopmental outcome of very low birth weight infants.

The effect of maternal milk feeding during the first 4 weeks of life on neurodevelopmental outcomes at 20 months corrected age (CA) of singleton very low birth weight (VLBW) (< 1.5 kg) infants was examined. Ninety-eight VLBW infants born from January 1997 to February 1999 were followed to 20 months CA (mean birth weight, 1012 g; gestational age, 27 weeks). Maternal milk intake was calculated as both mean milliliters per kilogram per day and graded doses. Outcomes included the Bayley Mental Development Index (MDI) and Psychomotor Development Index (PDI), and rates of cerebral palsy (CP) and of overall neurodevelopmental impairment. After adjusting for neonatal and social risk, results revealed no effect of maternal milk on outcomes. MDI was predicted by both social and neonatal risk, and PDI, CP, and neurodevelopmental impairment were predicted by neonatal risk. In this small, high-risk group of VLBW infants, the effects of social and neonatal risk appear to outweigh any possible benefits of maternal milk on neurodevelopmental outcome.