Prospective study of New Zealand very low birthweight infants: outcome at 7-8 years

Self-reported executive function problems in adults born very low birthweight

BACKGROUND

Executive function difficulties are common among children born very preterm and/or very low birthweight (<1500 g; VLBW), but little is known about whether they persist into adulthood.

OBJECTIVES

Examine the nature and pattern of self-reported executive functioning at 23 and 28 years of age using data from a national cohort study of adults born VLBW and a comparison group of same-age full-term (FT) born adults. Also examined were associations between executive function difficulties and socio-economic outcomes.

METHODS

All infants born VLBW in New Zealand during 1986 were prospectively included in an audit of retinopathy of prematurity (n = 413), with 250 (77% of survivors) followed to median age 28 years. A comparison group of FT adults was also recruited at age 23 and followed to 28 years (n = 100). Across both adult assessments, executive functioning was assessed using the Behaviour Rating Inventory of Executive Function-Adult Version (BRIEF-A) and analysed with semi-parametric models to examine the effects of age and group on executive function.

RESULTS

At 23 and 28 years, VLBW adults had increased risk of executive function impairment compared with FT adults in behaviour regulation (relative risk [CI] 2.37, 95% confidence interval (CI)1.27, 4.45), meta-cognition (RR 6.03, 95% CI 2.18, 16.78) and global functioning (RR 3.20, 95% CI 1.40, 7.28). Impaired global executive functioning was associated with lower socio-economic status (regression estimate [b] = -0.43, 95% CI -0.59, -0.27) and a reduced likelihood of home ownership by age 28 years (RR 0.98, 95% CI 0.96, 1.00), even after controlling for sex, ethnicity and parental socio-economic backgrounds for both groups.

CONCLUSION(S)

VLBW-born adults continue to experience more executive function difficulties in their everyday life relative to term controls at age 28 years. These difficulties were negatively associated with their socio-economic opportunities as young adults.

Perinatal and childhood predictors of general cognitive outcome at 28 years in a very-low-birthweight national cohort

AIM

To determine IQ at 26 to 30 years in very-low-birthweight (VLBW) adults compared with term-born controls; and to examine the stability of IQ in VLBW individuals between 7 to 8 years and 26 to 30 years, identify perinatal and social predictors of IQ, and assess the contribution of brain volume to IQ.

METHOD

At 26 to 30 years, 229 VLBW adults (71% survivors of prospectively enrolled national cohort) and 100 term-born controls were tested on the Wechsler Abbreviated Scale of Intelligence. For VLBW, IQ at 7 to 8 years, perinatal and social data were extracted from the data set, and 150 adults underwent volumetric cranial magnetic resonance imaging (MRI).

RESULTS

At 26 to 30 years, the mean adjusted difference between VLBW and controls for total IQ was 9.4 (95% CI 6.5-12.4) points. In VLBW individuals the correlation between IQ scores at 7 to 8 years and 26 to 30 years was 0.78. On multiple regression analysis, parental education was the strongest predictor of verbal and total IQ at both ages. Birthweight was a strong predictor of perceptual and total IQ. In VLBW individuals with MRI scans, the addition of brain volume as a variable increased the variance explained for perceptual and total IQ.

INTERPRETATION

VLBW adults have mean IQ scores 9 to 11 points below controls. Parental education and birthweight are the strongest predictors of IQ.

Visual function is reduced in young adults formerly born prematurely: a population-based study

Aims

To assess visual function in young adults born preterm and compare with full-term individuals of the same age.

Methods

Young adults, born preterm (birth weight ≤1500 g) in 1988–1990, previously included in a population-based study on the incidence of retinopathy of prematurity (ROP) in Stockholm County, Sweden were included. A control group of participants born at term, in the same area during the same time period, was used for comparison. Best-corrected visual acuities were assessed at distance and near with logMAR charts. Distance visual acuity was also measured with single symbols to calculate crowding. Visual fields were measured with Humphrey 24-2 and the mean deviation was noted. Contrast sensitivity was assessed with Vistech contrast sensitivity test and the area under the curve was calculated.

Results

Fifty-nine preterm (females 37) and 44 full-term (females 18) individuals were included. All individuals were between 25 and 29 years of age. Preterm individuals had significantly lower distance visual acuity (mean −0.08 (SD 0.11) vs −0.14 (SD 0.07) logMAR, p=0.009), near visual acuity (mean −0.08 (SD 0.11) vs −0.13 (SD 0.06) logMAR, p=0.049), mean deviation (mean −1.09 (SD 1.13) vs −0.80 (SD 1.03) dB, p=0.05) and contrast sensitivity (mean 2.02 (SD 0.19) vs 2.16 (SD 0.14), p<0.001) in the better eye compared with full-term individuals. The differences in distance visual acuity and contrast sensitivity were also evident after excluding persons with previous ROP and neurological complications. In multivariable analyses, treated ROP was a risk factor for reduced near visual acuity and visual fields.

Conclusion

Visual function seems to be reduced in prematurely born individuals even in adulthood. The reason may be prematurity per se since individuals without previous ROP or neurological complications are also affected.

Synopsis

Visual function, assessed as visual acuity, visual fields and contrast sensitivity, was reduced in young adults born preterm and previously included in a population-based study on the incidence of retinopathy of prematurity, as compared with controls.

Metabolic Syndrome in Very Low Birth Weight Young Adults and Controls: The New Zealand 1986 VLBW Study

OBJECTIVE

To assess the physical well-being and components of the metabolic syndrome in a national cohort of very low birth weight (VLBW) young adults and same age controls.

STUDY DESIGN

The New Zealand VLBW Study cohort prospectively included all infants with birth weight <1500 g born in 1986, with 338 (82%) surviving to discharge home. Height and weight were measured at age 7-8 years. The VLBW cohort (n = 229; 71% alive) and term-born controls (n = 100) aged 27-29 years were clinically assessed in a single center over 2 days, including assessment for components of the metabolic syndrome.

RESULTS

Compared with controls, both male and female VLBW adults were significantly shorter (P < .001), but only females were lighter (P < .001) and had lower mean body mass index (P = .044), fat mass, and body fat percentage. Males, but not females, had significantly higher systolic blood pressure (P = .028), but there were no significant differences in other components of the metabolic syndrome. There was no difference in the prevalence of the metabolic syndrome in VLBW adults compared with controls (males, 22.2% vs 11.1%; P = .15: females, 12.8% vs 13.1%; P = .95). Examining the VLBW cohort with logistic regression, male sex, gestational age <28 weeks, Māori/Pacific Island ethnicity, and body mass index >90th percentile at age 7-8 years were significant predictors for the metabolic syndrome at age 27-29 years, with ORs of 2-4.

CONCLUSIONS

Systolic blood pressure in males was the only component of the metabolic syndrome that was significantly elevated in VLBW adults compared with controls. Extreme prematurity (<28 weeks) and body mass index >90th percentile at age 7-8 years were significant predictors of the metabolic syndrome at age 27-29 years.

TRIAL REGISTRATION

Registered at the Australian Clinical Trials Registry: ACTRN12612000995875.

The New Zealand 1986 very low birth weight cohort as young adults: mapping the road ahead

Background

Very low birth weight (less than 1500 g) is associated with increased morbidity and costs of health care in childhood. Emerging evidence suggests these infants face a range of health and social problems as young adults. We studied all New Zealand very low birth weight infants born in 1986 (when 58 % were exposed to antenatal corticosteroids) in infancy, with later follow-up at 7 to 8 years and 23 to 24 years. We now aim to assess the cohort at 26–28 years compared with controls.

Methods/design

The case sample will comprise a minimum of 250 members of the 1986 New Zealand national very low birth weight cohort (77 % of survivors). Outcomes will be compared with a control group of 100 young adults born at term in 1986. Following written informed consent, participants will travel to Christchurch for 2 days of assessments undertaken by experienced staff. Medical assessments include growth measures, vision, respiratory function, blood pressure and echocardiogram, renal function, dental examination and blood tests. Cognitive and neuropsychological functioning will be assessed with standard tests, and mental health and social functioning by participant interview. A telephone interview will be conducted with a parent or significant other person nominated by the respondent to gain a further perspective on the young person’s health and functioning. All those born at less than 28 weeks’ gestation, plus a random subset of the cohort to a total of 150 cases and 50 controls, will be offered cranial magnetic-resonance imaging. Statistical analysis will examine comparison with controls and long-term trajectories for the very low birth weight cohort.

Discussion

The research will provide crucial New Zealand data on the young adult outcomes for very low birth weight infants and address gaps in the international literature, particularly regarding cardiovascular, respiratory, visual and neurocognitive outcomes. These data will inform future neonatal care, provide evidence-based guidelines for care of preterm graduates transitioning to adult care, and help shape health education and social policies for this high risk group.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12612000995875. Registered 1 October 2012

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0413-9) contains supplementary material, which is available to authorized users.

Visual-perceptual impairment in children with cerebral palsy: a systematic review

AIM

Visual perception is one of the cognitive functions often impaired in children with cerebral palsy (CP). The aim of this systematic literature review was to assess the frequency of visual-perceptual impairment (VPI) and its relationship with patient characteristics.

METHOD

Eligible studies were relevant papers assessing visual perception with five common standardized assessment instruments in children with CP published from January 1990 to August 2011.

RESULTS

Of the 84 studies selected, 15 were retained. In children with CP, the proportion of VPI ranged from 40% to 50% and the mean visual perception quotient from 70 to 90. None of the studies reported a significant influence of CP subtype, IQ level, side of motor impairment, neuro-ophthalmological outcomes, or seizures. The severity of neuroradiological lesions seemed associated with VPI. The influence of prematurity was controversial, but a lower gestational age was more often associated with lower visual motor skills than with decreased visual-perceptual abilities.

INTERPRETATION

The impairment of visual perception in children with CP should be considered a core disorder within the CP syndrome. Further research, including a more systematic approach to neuropsychological testing, is needed to explore the specific impact of CP subgroups and of neuroradiological features on visual-perceptual development.

Psychosocial outcomes of young adults born very low birth weight

OBJECTIVE

To assess the early adult health, education, and social functioning of a national cohort of very low birth weight (VLBW) infants born in 1986 in New Zealand compared with a control group of young adults born the same year. The impact of neurodevelopmental disability at age 7 to 8 years on young adult outcomes was examined.

METHODS

Participants underwent a comprehensive face-to-face interview that included standardized assessment tools and previously used custom written survey items.

RESULTS

We interviewed 230 VLBW young adults (71% of survivors) and 69 controls at age 22 to 23 years. VLBW young adults were 5.6 kg lighter and 4.2 cm shorter than controls, had lower rates of tertiary education/training (percentage difference [95% confidence interval]: -13.1 [-21.6 to -1.8]) and university degree completion (-15.6 [-28.0 to -4.8]), had more often been welfare dependent (23.5 [10.2 to 35.0]), had few or no friends (20.5 [7.2 to 32.2]), and more often had wheeze in the past year (20.1 [9.0 to 28.6]). However, in many areas there were no differences between the VLBW cohort and controls, and VLBW adults rated their overall quality of life and behavioral functioning similarly to their peers. Those with previous disability had poorer social, occupational, and physical functioning than other VLBW young adults.

CONCLUSIONS

Despite some evidence of health, educational, and social difficulties, former VLBW young adults obtained similar scores across many aspects of health and social functioning as their same age peers, with some differences largely confined to those with previous disability.

Development of refractive error in individual children with regressed retinopathy of prematurity

PURPOSE

We investigated longitudinally the refraction development in children with regressed retinopathy of prematurity (ROP), including those with and those without a history of peripheral retinal laser photocoagulation.

METHODS

Longitudinal (0-7 years) cycloplegic refraction data were collected prospectively for two groups of preterm children: severe ROP group included those with regressed ROP following bilateral panretinal laser photocoagulation (n = 37; median gestational age [GA] = 25.2; range, 22.7-27.9 weeks) and mild/no ROP group included those with spontaneously regressed ROP or no ROP (n = 27; median GA = 27.1; range, 23.1-32.0 weeks). Analyses were based on spherical equivalent (SEQ), anisometropia, astigmatism, and age (corrected for gestation).

RESULTS

The prevalence, magnitude, and rate of myopic progression all were significantly higher in the severe ROP group than in the mild/no ROP group. Longitudinal SEQ in the severe ROP group were best fit with a bilinear model. Before 1.3 years old, the rate of myopic shift was -4.7 diopters (D)/y; after 1.3 years, the rate slowed to -0.15 D/y. Longitudinal SEQ in the mild/no ROP group was best fit with a linear model, with a rate of -0.004 D/y. Anisometropia in the severe ROP group increased approximately three times faster than in the mild/no ROP group. In the severe ROP group, with-the-rule astigmatism increased significantly with age.

CONCLUSIONS

The severe ROP group progressed rapidly toward myopia, particularly during the first 1.3 years; anisometropia and astigmatism also increased with age. The mild/no ROP group showed little change in refraction. Infants treated with laser photocoagulation for severe ROP should be monitored with periodic cycloplegic refractions and provided with early optical correction.

Outcomes of very-low-birthweight infants at 3 years of age born in 2003-2004 in Japan

BACKGROUND

The aim of this study was to describe and compare neurodevelopmental outcomes with birthweight (BW) groups at 250-g intervals of very-low-birthweight (VLBW) infants at 3 years of age in a multicenter cohort in Japan.

METHODS

A total of 3104 VLBW infants born in 2003 and 2004 registered in a NICU-network database were followed in the study. Neurodevelopmental impairment (NDI) was defined as any of the following impairments: cerebral palsy, unilateral or bilateral blindness, severe hearing impairment, or developmental delay; a developmental quotient (DQ) <70 measured using the Kyoto Scale of Psychological Development test or judged by physicians in infants without the test.

RESULTS

A total of 257 infants died and follow-up data were obtained from 1826 infants. Of the 1826 infants, 155 (8.5%) had cerebral palsy, 25 (1.4%) had visual impairment, and 12 (0.7%) had hearing impairment. Of the 1197 infants in whom DQ was measured, 184 (15.4%) had DQ < 70. The proportion of NDI in the evaluated infants was 19.2% (n= 350), ranging from 11.9% (BW 1251-1500 g) to 42.0% (BW ≤ 500 g). Odds ratios (95%CI) of NDI or death against the group BW 1251-1500 g were 20.62 (13.29-31.97) in BW ≤ 500 g, 7.25 (5.45-9.64) in BW 501-750 g, 2.85 (2.12-3.82) in BW 751-1000 g and 1.18 (0.85-1.64) in BW 1001-1250 g.

CONCLUSION

The increasing proportion of NDI or death, an indicator of adverse outcome, was associated with decrement in the BW of the groups. Although we have to consider a bias due to loss of follow-up data, the incidence of NDI was similar to previous overseas cohort studies despite the higher survival proportion in our study.

Relationship Between Postural Control and Fine Motor Skills in Preterm Infants at 6 and 12 Months Adjusted Age

We examined the relationship between postural control and fine motor skills of preterm infants at 6 and 12 mo adjusted age. The Alberta Infant Motor Scale was used to measure postural control, and the Peabody Developmental Motor Scales II was used to measure fine motor skills. The data analyzed were taken from 105 medical records from a preterm infant follow-up clinic at an urban academic medical center in south Taiwan. Using multiple regression analyses, we found that the development of postural control is related to the development of fine motor skills, especially in the group of preterm infants with delayed postural control. This finding supports the theoretical assumption of proximal–distal development used by many occupational therapists to guide intervention. Further research is suggested to corroborate findings.

Parent-perceived barriers to participation in children and adolescents with cerebral palsy

AIM

To pilot the use of the Craig Hospital Inventory of Environmental Factors (CHIEF) questionnaire to ascertain information regarding barriers to participation experienced by a sample of New Zealand children with cerebral palsy.

METHODS

The CHIEF questionnaire was administered to parents/caregivers of a consecutive sample of 32 children with cerebral palsy attending a paediatric tertiary clinic in Auckland. Twenty-three children walked independently, 5 used walking aides and four used a wheelchair. Twenty-four of the 32 parent-respondents provided contextual feedback for their responses and wider issues relating to the topic.

RESULTS

The barriers to participation most commonly reported by parents were attitudes at school (72%) and in the community (56%), difficulties accessing personal equipment (59%), and the natural environment and built surroundings (56%). Contextual information from families generally supported their answers to the questionnaire but highlighted that some parents had confused the 'not applicable' and 'never' options. Discrepancy between scores on the policy-related questions and later contextual feedback suggested that the policy subscale did not fully capture family concerns about limited availability of public funding for equipment, therapy, and educational support.

CONCLUSIONS

The CHIEF instrument proved easy to use in a clinic setting. However, parent-respondent feedback highlighted the difficulties in interpreting responses to some items when the instrument is used in isolation to quantify environmental barriers to participation. The results highlight the need to develop research approaches and tools that can explore barriers to participation by children with cerebral palsy taking account of socio-economic and other relevant contextual information.

Admission of all gestations to a regional neonatal unit versus controls: neonatal morbidity

AIMS

To describe the neonatal course and morbidity of all infants admitted to the regional neonatal intensive care unit (NICU) at Christchurch Women's Hospital (CWH) and to compare these with term control infants who were not admitted, in one calendar year. Infants in both NICU and control cohorts were enrolled in a 2-year follow-up study.

METHODS

All infants born over a 12-month period from February 2001 and admitted to the NICU, whose parents were domiciled in a defined geographical region, were eligible for study, together with every eighth healthy infant born at term and not admitted (to a total of 300). Comprehensive perinatal and neonatal data were collected for all enrolled infants.

RESULTS

A total of 387 NICU infants (86% eligible) were enrolled in the study together with 306 controls. Forty-one percent of NICU admissions were term and 40% were 33-36 weeks gestation. Term NICU infants were more likely to be born following induction of labour or by Caesarean section (34%, of which 50% were pre-labour) than control infants (18%, of which 32% were pre-labour). Infants of <28, 28-32, 33-36 and > or =37 weeks accounted for 74, 16, 7 and 3% of assisted ventilation days and 18, 31, 31 and 20% of total baby days, respectively.

CONCLUSIONS

The need for assisted ventilation and length of NICU stay was inversely proportional to gestation. However, preterm infants of 28 weeks gestation and greater, as well as term infants, account for a high proportion of the NICU workload.

Admissions of all gestations to a regional neonatal unit versus controls: 2-year outcome

AIMS

To assess neurodevelopmental outcome at 2 years for neonatal intensive care unit (NICU) admissions compared with controls, and to trial a parent-reporting scheme.

METHODS

All infants admitted to the NICU at Christchurch Women's Hospital over a 12-month period and whose parents were domiciled in a defined geographical region were eligible for study, together with every eighth term infant not admitted (to a total of 300). Parents completed a two-page questionnaire on their child's 2nd birthday. All infants <28 weeks gestation and a random 300 NICU admissions and 108 controls underwent a paediatric examination and Bayley II assessment at 2 years of age.

RESULTS

A total of 387 NICU infants (86% eligible) and 306 controls were enrolled. At 2 years of age, 276 NICU infants (89% survivors) and 94 controls (87%) had some follow up. For infants of <33 weeks, 33-36 weeks, > or =37 weeks gestation and controls, the percentage >1 SD below the mean on the Bayley Mental Development Index scales were 33.3, 36.5, 44.6 and 24.1, respectively (P= 0.03); on the Psychomotor Developmental Index scales were 30.0, 29.1, 41.1 and 19.5 (P= 0.02) and the percentage with any cerebral palsy were 11.1, 2.8, 5.2 and 1.2.

CONCLUSIONS

At 2 years of age, NICU graduates have more developmental problems than controls across a range of measures. In many cases, term NICU graduates have the least favourable outcome. There was only moderate agreement between parents' reporting of moderate or severe developmental disability by means of a questionnaire, compared with professionals (kappa statistic 0.38), with parents tending to underestimate problems.

Severe retinopathy of prematurity and visual outcomes in British Columbia: a 10-year analysis

OBJECTIVE

To describe the incidence trend and long-term visual outcomes of infants diagnosed with stages 3 to 4 retinopathy of prematurity (ROP) or laser-treated ROP born in British Columbia (Canada).

STUDY DESIGN

Data from all (n=1384) neonates with birth weight (BW) <1250 g, admitted to British Columbia Children's Hospital between period 1 (January 1992 to December 1996) and period 2 (January 1997 to December 2001) were analyzed. Ophthalmologic records of infants with stages 3 to 4 ROP or laser-treated ROP were abstracted. chi(2)- and t-test were used to compare neonatal characteristics between periods. Logistic regression was used to identify risk factors associated with visual impairment (defined as visual acuity <or=20/60 or visual field restriction of 20 degrees binocularly).

RESULT

Of 1159 surviving infants, 887 were examined for acute ROP (473 in period 1, 414 in period 2). Stages 3 to 4 ROP or laser-treated ROP were present in 35 infants in period 1 (7%) and 59 in period 2 (14%), P<or=0001. Infants born in period 2 had lower mean BW and gestational age. Among infants who developed severe ROP or laser-treated ROP, binocular visual impairment was present in eight children in period 1 and seven in period 2. Refractive errors, including myopia and astigmatism, were increased in period 2. Children who developed periventricular leucomalacia had the highest risk of visual impairment at 4 to 6 years of age.

CONCLUSION

During the 10-year study period, a significant increase in rates of stages 3 to 4 or laser-treated ROP was not associated with increases in visual impairment rates.

Long-term follow-up of visual functions in prematurely born children--a prospective population-based study up to 10 years of age

INTRODUCTION

Prematurely born children have an increased risk of ophthalmologic problems. There is still no consensus on how they should be followed. The purpose of this study was to evaluate predictive factors for problems in premature children at ten years of age and to discuss follow-up recommendations.

MATERIALS AND METHODS

One hundred ninety-nine children with a birth weight of 1500 g or less were screened for retinopathy of prematurity (ROP) in the neonatal period and thereafter ophthalmologically examined at 6 months, 1.5, 2.5, 3.5, and 10 years of age. "Visual dysfunction" at ten years of age was defined as visual acuity > or =0.1 logMAR and/or strabismus and/or subnormal contrast sensitivity. Multiple regression analyses were used to evaluate risk factors at an early age, which could predict problems at ten years of age.

RESULTS

Twenty-five percent of the cohort had visual dysfunction at ten years of age. Neurological complications, cryotreated ROP, anisometropia, and astigmatism were risk factors. The sensitivity was 75.5%, and the specificity 80.7% for the detection of visual dysfunction at ten years of age when all children with neurological complications, cryotreated ROP, strabismus, anisometropia > or =1 diopters (D) at 2.5 years, and astigmatism > or =2 D at 2.5 years were included in further follow-up.

CONCLUSIONS

Repeated ophthalmologic follow-up of prematurely born children should be performed in those with treated ROP and/or neurological conditions. For a third group without such problems, at least one follow-up is recommended. Such an examination also provides a good opportunity to identify neurological problems that warrant further ophthalmologic follow-up.

Early delayed language development in very preterm infants: evidence from the MacArthur-Bates CDI

This study examined the effects of being born very preterm on children's early language development using prospective longitudinal data from a representative regional cohort of 90 children born very preterm (gestational age <33 weeks and/or birth weight <1,500 grams) and a comparison sample of 102 children born full term (gestational age 38-41 weeks). The MacArthur-Bates Communicative Development Inventory: Words and Sentences (CDI-WS) was used to assess children's language development at age 2;0 (corrected for gestational age at birth). Clear linear relationships were found between gestational age at birth and later language outcomes, with decreasing gestational age being associated with poorer parent-reported language skills. Specifically, children born extremely preterm (<28 weeks' gestation) tended to perform less well than those born very preterm (28-32 weeks' gestation), who in turn performed worse than children born full term (38-41 weeks' gestation). This pattern of findings was evident across a range of outcomes spanning vocabulary size and quality of word use, as well as morphological and syntactic complexity. Importantly, associations between gestational age at birth and language outcomes persisted after statistical control for child and family factors correlated with both preterm birth and language development. These findings demonstrate the presence of pervasive delays in the early language development of children born very preterm. They also highlight the importance of gestational age in predicting later language risk in this population of infants.

ADHD-like hyperactivity, with no attention deficit, in adult rats after repeated hypoxia during the equivalent of extreme prematurity

The most common behavioural disorder seen in children and adolescents born extremely prematurely is attention deficit hyperactivity disorder (ADHD). The hyperactive/impulsive sub-type of ADHD or the inattentive sub-type or the hyperactive/impulsive/inattentive sub-type can be evident. These sub-types of ADHD can persist into adulthood. The aim of this study was to investigate the relevance of a new immature rat model of repeated hypoxic exposure to these behavioural characteristics of extreme prematurity. More specifically, this study aimed to measure ADHD-like hyperactivity in response to delayed reward, and inattention, in repeated hypoxic versus repeated normoxic rats. Sprague-Dawley rats were exposed to either repeated hypoxia or repeated normoxia during postnatal days (PN) 1-3. The rat brain during PN1-3 is generally considered to be developmentally equivalent to the human brain during extreme prematurity. The rats were then behaviourally tested at 16 months-of-age on a multiple component fixed interval-extinction test. This test detects ADHD-like hyperactivity in response to delayed reward, as well as inattention. It was found that the repeated hypoxic rats exhibited ADHD-like hyperactivity in response to delayed reward, but no attention deficit, when compared to repeated normoxic rats. These findings provide a new animal model to investigate the biological mechanisms and treatment of ADHD-like hyperactivity due to repeated hypoxia during the equivalent of extreme prematurity.

Effects of breast milk on the severity and outcome of neonatal abstinence syndrome among infants of drug-dependent mothers

OBJECTIVE

The purpose of this research was to assess the effects of breast milk on the severity and outcome of neonatal abstinence syndrome.

METHODS

We conducted a retrospective chart review of 190 drug-dependent mother and infant pairs. Patients were categorized according to the predominant type of milk consumed by the infant on the fifth day of life (breast milk: n = 85 or formula: n = 105). The Finnegan's scoring system was used to monitor withdrawal, and medication was commenced if there were 2 scores of > or = 8.

RESULTS

Mean Finnegan scores were significantly lower in the breast milk group during the first 9 days of life even after stratifying for prematurity and exposure to polydrug and methadone. Significantly fewer infants required withdrawal treatment in the breast milk group. The median time to withdrawal occurred considerably later in breast milk group. In a multivariate analysis controlled for exposure to drugs of high risk of neonatal abstinence syndrome, polydrug, and prematurity, breast milk group was associated with lower need for neonatal abstinence syndrome treatment.

CONCLUSIONS

Breast milk intake is associated with reduced neonatal abstinence syndrome severity, delayed onset of neonatal abstinence syndrome, and decreased need for pharmacologic treatment, regardless of the gestation and the type of drug exposure.

Medidas psicofísicas e eletrofisiológicas da função visual do recém nascido: uma revisão

O sistema visual apresenta muitas funções ao nascimento. O processo de amadurecimento destas funções demanda um tempo variado. Neste trabalho, inicialmente descreveremos como a psicofísica e a eletrofisiologia visual tem colaborado para a medida e o estudo do desenvolvimento de três funções visuais: acuidade visual, sensibilidade ao contraste e visão de cores. Num segundo momento, discutimos sobre como a medida e o desenvolvimento destas funções podem estar prejudicados em patologias que afetam o sistema visual, como a prematuridade e a paralisia cerebral.

Outcomes for high risk New Zealand newborn infants in 1998-1999: a population based, national study

OBJECTIVE

To determine short term morbidity and mortality outcomes, provision of care, and treatments for a national cohort of high risk infants born in 1998-1999 and admitted to New Zealand neonatal intensive care units (NICUs).

SETTING

All level III (six) and level II (13) NICUs in New Zealand.

METHODS

Prospective audit by the Australian and New Zealand Neonatal Network (ANZNN) of all infants defined as "high risk" (born at < 32 weeks gestation or < 1500 g birth weight, or received assisted ventilation for four hours or more, or had major surgery). Data were collected from birth until discharge home or death.

RESULTS

There were 3368 high risk infants (3.0% of all live births), comprising 1241 (37%) < 32 weeks gestation, 1084 (32%) < 1500 g, 3156 (94%) who received assisted ventilation, and 243 (7%) who received major surgery (categories overlap). Most infants (87%) received some care in tertiary hospitals, and 13% were cared for entirely in non-tertiary hospitals. Survival was 91% for infants < 32 weeks gestation, 97% for infants > or = 32 weeks gestation who received assisted ventilation, and 92% for infants > or = 32 weeks gestation who had major surgery. The proportion of very preterm infants who survived free of early major morbidity was 11%, 28%, 53%, 81%, and 90% for infants born at < 24, 24-25, 26-27, 28-29, and 30-31 weeks gestation respectively.

CONCLUSIONS

These unique population based national data provide contemporary information on the care and early morbidity and mortality outcomes for all high risk infants, whether cared for in hospitals with level III or level II NICUs.

Improved outcomes for very low birthweight infants: evidence from New Zealand national population based data

OBJECTIVE

To compare the survival and short term morbidity of all New Zealand very low birthweight (VLBW) infants born in two epochs, 1986 and 1998-1999.

SETTING

All level III and level II neonatal intensive care units (NICUs) in New Zealand.

METHODS

In 1986, data were prospectively collected for a study of retinopathy of prematurity (ROP). In 1998-1999, prospective data were collected by the Australian and New Zealand Neonatal Network (ANZNN). Both cohorts included all VLBW infants born during the calendar year and admitted to a NICU. Data were collected from birth until discharge home or death.

RESULTS

More VLBW infants were admitted for care in 1998-1999 (n = 1084, 0.96% of livebirths) than in 1986 (n = 413, 0.78% of livebirths; p < 0.001), including a higher proportion of VLBW infants of < 1000 g birth weight (38% v 32% respectively; p < 0.05). Survival to discharge home increased from 81.8% in 1986 to 90.3% in 1998-1999 (p < 0.001). The 1998-1999 cohort had a higher proportion of infants born in a hospital with a level III NICU (87% v 72% in 1986; p < 0.001) and receiving antenatal corticosteroids (80% v 58% in 1986; p < 0.001). In 1998-1999, the incidence of several morbidities had decreased compared with 1986, including oxygen dependency at 28 days (29% v 39% respectively; p = 0.001) and at 36 weeks postmenstrual age (16% v 23%; p = 0.002), grade 1 intraventricular haemorrhage (IVH) (8% v 24%; p < 0.001), grade 2/3 IVH (5% v 11%; p < 0.001), and stage 3/4 ROP for infants < 1000 g (6% v 13%; p < 0.001).

CONCLUSIONS

The outlook for VLBW infants in New Zealand has improved since 1986.

The association of indicators of fetal growth with visual acuity and hearing among conscripts

Impaired fetal growth is associated with increased susceptibility to several chronic diseases. We studied the association between birth weight, indicators of disproportional fetal growth, and impaired visual acuity and hearing in 4,300 conscripts from a well-defined region in Denmark from August 1, 1993, to July 31, 1994. From the standard health examination for conscripts, we obtained data on sight based on the Snellen's chart and data on hearing acuity based on audiometry. By means of record linkage, we obtained data on outcomes for the conscripts at birth from the Medical Birth Registry. From this registry, we have data on birth weight, gestational age, and birth length that were recorded from existing computerized registers based on the records of midwives. A birth weight of less than 3,000 gm and a body mass index at birth of less than 3.4 were associated with reduced visual acuity and impaired hearing. The results could be due to fetal brain programming or due to confounding, by early birth trauma or other factors.

Breast milk feeding and cognitive ability at 7-8 years

OBJECTIVE

To examine the association between duration of breast milk feeding and cognitive ability at 7-8 years in a birth cohort of very low birthweight infants.

DESIGN

280 survivors from a national birth cohort of 413 New Zealand very low birthweight infants born in 1986 were assessed at age 7-8 years on measures of verbal and performance intelligence quotient (IQ) using the WISC-R. At the same time mothers were questioned as to whether they had elected to provide expressed breast milk at birth and the total duration of breast milk feeding.

RESULTS

Some 73% of mothers provided expressed breast milk and 37% breast fed for four months or longer. Increasing duration of breast milk feeding was associated with increases in both verbal IQ (p < 0.001) and performance IQ (p < 0.05): children breast fed for eight months or longer had mean (SD) verbal IQ scores that were 10.2 (0.56) points higher and performance IQ scores that were 6.2 (0.35) points higher than children who did not receive breast milk. These differences were substantially reduced after control for selection factors associated with receipt of breast milk. Nevertheless, even after control for confounding, there remained a significant (p < 0.05) association between duration of breast milk feeding and verbal IQ: children breast fed for eight months or longer had adjusted mean (SD) verbal IQ scores that were 6 (0.36) points higher than the scores of those who did not receive breast milk.

CONCLUSIONS

These findings add to a growing body of evidence to suggest that breast milk feeding may have small long term benefits for child cognitive development.

Very low birthweight and asthma by age seven years in a national cohort

Several studies have suggested that very low birthweight (VLBW < 1500 g) is associated with increased rates of respiratory problems in childhood and that the presence of chronic lung disease further increases the risk. We aimed to assess rates of asthma at 7-8 years of age in a national cohort of VLBW infants born in 1986 and for whom perinatal data were available. Two hundred ninety-nine former VLBW children (96% of surviving children living in New Zealand) were assessed at a home visit. Parents were asked a comprehensive questionnaire, including three questions aimed at assessing morbidity from asthma: 1) was the child diagnosed as having asthma before age 7 years; 2) was the child still experiencing asthma at the age of 7 years; and 3) was the child prescribed daily medication for asthma at the age of 7 years. Overall, 50% of the cohort had been diagnosed with asthma before age 7, compared with 27% of a sample of New Zealand children assessed contemporaneously in an international study; 32% had asthma at age 7, and 11% were taking daily medication. All three categories of asthma were associated with a family history of asthma, but there was no association with any perinatal factors. A diagnosis of asthma before age 7 was more likely when the mother smoked in pregnancy (P < 0.005) and currently smoked (P < 0.01), and trended so when parents lacked high school qualifications and in Maori or Pacific Island families (P < 0.10). In contrast, daily medication was more frequent when parents had educational qualifications and in non-Maori or Pacific Island families (P < 0.05). On multiple logistic regression, a family history of asthma was a significant predictor for any and current asthma (P < 0.001) and daily medication (P < 0.05); maternal smoking in pregnancy was a significant predictor for any asthma (P < 0.05); and non-Maori or Pacific Island ethnicity was a significant predictor for asthma treatment (P < 0.05). We conclude that rates of childhood asthma are high in this VLBW cohort, but the high prevalence appears to be unrelated to perinatal factors, including respiratory morbidity. There are suggestions that social factors contribute to both asthma risk and treatment.

Changes in the aetiology of hearing impairment in deaf-blind pupils and deaf infant pupils at an institute for the deaf

An aetiological study was performed on 57 pupils at the deaf-blind department of the Institute for the Deaf at Sint-Michielsgestel, The Netherlands, in the school year 1998-1999 and on 49 deaf-blind pupils at the same department in the school year 1986-1987. The pupils were 5-20 years of age. In addition, the aetiologies were studied in 55 deaf infant pupils in 1998 and compared with those of 68 deaf infant pupils in 1988. Their age was 1-5 years. All the pupils showed hearing impairment with thresholds of >60 dB HL. Among the deaf-blind pupils and deaf infant pupils, there were several cases with rare hereditary syndromes. The prevalence of acquired causes of deafness, especially congenital rubella, had decreased over the years, whereas perinatal causes of deafness had increased. Chromosomal anomalies were found in 15% of the infant pupils in 1998. Over the study period, the percentage of pupils with multiple handicaps increased from 25 to 38%.

Risk factors for cerebral palsy in very low-birthweight infants in the 1980s and 1990s

One-hundred twenty-nine very low-birthweight infants were treated in Newborn and Infant Care Department of Children's Memorial Health Institute between 1985 and 1994; 89 were taken to prospective neurodevelopmental care. The newborns were divided into two groups. Group I had 38 preterm infants born from 1985 to 1989 and followed up at 7 to 11 years of age. Group II had 51 very low-birthweight infants treated from 1990 to 1994 and followed up at 2 to 5 years of age. Complicated, multiple pregnancy, normal delivery, and extremely low birthweight were significantly more frequent in group II. Very low-birthweight infants were frequently born by cesarean section in severe asphyxia. Only four (7.8%) newborns received surfactant therapy. From 1990 to 1994, respiratory distress syndrome III and IV, and a longer respiratotherapy period were significantly more frequent. From 1985 to 1994, the frequency of sepsis, periventricular leukomalacia, and normal ultrasonography was constant. Intraventricular hemorrhage I, II, and IV were frequently present in the 1990s, and intraventricular hemorrhage III was frequent in the 1980s. Cerebral palsy was diagnosed in 11 (28.9%) children in group I and 18 (35.2%) in group II (not statistically different). Multiple and complicated pregnancy, cesarean section, severe asphyxia, and respiratory distress syndrome did not increase the risk of cerebral palsy in very low-birthweight infants. Periventricular leukomalacia has a more predictive value for cerebral palsy in these infants than did intraventricular hemorrhage.

Functional outcomes in self-care, mobility, communication, and learning in extremely low-birth weight infants

Gaps have existed in specifying degrees of severity of cerebral palsy assessment of self-care and communicative competencies, and specifying age-appropriate preschool educational and behavioral competencies. Imbedded in the concept of measuring functional status is the interaction between health and neurologic impairments, developmental challenges and competencies, family resources and disadvantages, and the child's current status. In reviewing historic outcomes of severe ROP over the past 40 years, it was noted that severe ROP caused blindness in 2% to 11% of survivors. There was a constant observation that approximately 50% of severe ROP survivors with blindness had multiple functional and developmental challenges beyond blindness alone. Similarly, in reviewing outcomes of cerebral palsy, it is imperative to describe the severity of cerebral palsy and functional consequences in motor, selfcare, communication, and learning. The reason to measure the functional status of children with neurodevelopmental impairments before first grade is that the degrees of severity of these disorders can be specified before attending school with peers. Subtler aspects of neurodevelopmental impairments need to assess impact on literacy, information learning, written language, social competencies with peers, and recreational and community participation. In this way, we can understand the vulnerabilities and resiliences of children and families of VLBW and ELBW status. This is a critical step in understanding long-term quality of life and independent living issues. In addition, our efforts can address those factors and pathways whereby multiple disabilities and multiple functional limitations cluster. Our biomedical intervention can prioritize strategies that lessen severe multiple disabilities and simultaneously support families, when despite our best efforts functional challenges are life long.

Causes of hearing impairment in deaf pupils with a mental handicap

An aetiological study was performed on 122 deaf pupils (57 aged < 20 years, 65 aged > 20 years) at the Institute for the Deaf in Sint-Michielsgestel, The Netherlands. Besides hearing impairment with thresholds of > 60 dB HL, all the participants had a mental handicap with a non-verbal IQ of 40-80. Sixteen per cent of them were of non-Dutch origin. The cause of hearing impairment was acquired in 48%, inherited in 17%, chromosomal in 4% and unknown in 30%. In comparison with other studies on the aetiology of childhood deafness, acquired causes predominated over inherited causes, which may be typical of deafness combined with a mental handicap. We found a significant predominance of non-Dutch pupils among the rubella aetiology cases and male predominance among the hearing impaired pupils in general.

Is sudden infant death syndrome still more common in very low birthweight infants in the 1990s?

OBJECTIVE

To determine the rate of sudden infant death syndrome (SIDS) in very low birthweight children (VLBW) relative to children with low (LBW) and normal birthweights.

DESIGN, SETTING AND SUBJECTS

Cohort study of consecutive live births in Victoria, 1993-1997 inclusive.

MAIN OUTCOME MEASURES

All sudden unexpected deaths in early childhood over this five-year period; all deaths from SIDS (defined as a sudden unexpected death without a definite pathological explanation); and the proportion of SIDS in live births in three birthweight subgroups (VLBW, 500-1499 g; LBW, 1500-2499 g; and normal birthweight, > 2499 g).

RESULTS

There were 316,028 live births (with known birthweight) in Victoria over the five-year period; 224 (0.71 per 1000 live births) died unexpectedly. In 10 of these deaths there was a definite pathological explanation, giving a rate of SIDS of 0.68 per 1000 live births. The rate of SIDS in VLBW children was 2.52 per 1000 live births, lower than the rate reported before the 1990s. The rate of SIDS in VLBW children was not significantly different from the rate in LBW children of 1.98 per 1000 live births (difference per 1000 live births, 0.53; 95% CI, -1.45 to 2.52), but was significantly higher than the rate in normal birthweight children of 0.59 per 1000 live births (difference per 1000 live births, 1.93; 95% CI, 0.06-3.79).

CONCLUSIONS

The rate of SIDS in VLBW children has fallen in the 1990s, along with the overall fall in the rate of SIDS, but remains higher than that in normal birthweight children.

Cognitive, educational, and behavioural outcomes at 7 to 8 years in a national very low birthweight cohort

AIMS

To examine cognitive, behavioural, and educational outcomes in middle childhood among a birth cohort of very low birthweight children.

METHODS

Two hundred and ninety eight survivors from a national birth cohort of 413 New Zealand very low birthweight (VLBW) children born in 1986 were assessed at 7 to 8 years of age on measures of behaviour, cognitive ability, school performance and the need for special education. These outcomes were compared with the same measures in a general population sample of over 1000 children studied at a similar age.

RESULTS

The VLBW children had significantly higher rates of problems and poorer levels of functioning across all outcome measures than the general child sample. These differences persisted even after control for variability in social, family, and other characteristics of the two samples and for the degree of sensorineural disability. There was evidence of a gradient of risk with birthweight, with extremely low birthweight children having generally higher rates of problems and difficulties than other VLBW children after covariate control.

CONCLUSIONS

The findings are consistent with a growing body of research evidence which suggests that premature and VLBW infants are at increased risk of longer term morbidity and functional impairment in middle childhood.

Prospective study of New Zealand infants with birth weight less than 1500 g and screened for retinopathy of prematurity: visual outcome at age 7-8 years

AIM

To determine the visual outcome at 7-8 years in very low birth weight (VLBW: birth weight < 1500 g) infants screened for retinopathy of prematurity (ROP).

METHODS

In 1986 all 413 VLBW infants admitted to neonatal units in New Zealand were enrolled in a prospective study of acute ROP. Surviving infants were traced and assessed at a home visit. Visual assessment comprised examination for abnormal and range of eye movements, visual fields, distance and near visual acuity, stereopsis, and photorefraction.

RESULTS

Of 338 infants surviving to discharge, 313 (93%) had been examined for acute ROP. ROP was present in 66 (21%: ROP+), absent in 247 (ROP-), with 25 not examined (NA). 298 children (96% survivors resident in New Zealand: 91% all survivors) were assessed. Any visual problem occurred in 79% ROP+ and 60% ROP-/NA (p < 0.01). Distance visual acuity less than 4/10 in the worse eye occurred in 29% ROP+ and 15% ROP-/NA (p < 0.05); and in the better eye in 19% ROP+ and 5% ROP-/NA (p < 0.001). Any myopia in the worse eye occurred in 36% ROP+ and 18% ROP-/NA (p < 0.01); and in the better eye in 25% ROP+ and 11% ROP-/NA (p < 0.01). Strabismus, including treated, occurred in 33% ROP+ and 19% ROP-/NA (p < 0.05). Overall, 11% had astigmatism and 18% hypermetropia with no difference between the groups.

CONCLUSION

In a population based study it was confirmed that VLBW is associated with an increased risk of visual problems at school age. A history of ROP is associated with an additional risk of poor outcome, including a near doubling of poor distance acuity, myopia, and strabismus.