Neurological assessment of the preterm infant

Flash VEP in clinically stable pre-term and full-term infants

PURPOSE

Pre-term infants are at risk of abnormal visual development that can range from subtle to severe. The aim of this study was to compare flash VEPs in clinically stable pre-term and full-term infants at 6 months of age.

METHODS

Twenty-five pre-term and 25 full-term infants underwent flash VEP testing at the age of 6 months. Monocular VEPs were recorded using flash goggles on a RETIscan system under normal sleeping conditions. Amplitude and peak time responses of the P2 component in the two eyes were averaged and compared between the two groups. Multiple regression analyses were performed to assess the relationship of the P2 responses with birth weight (BW) and gestational age (GA).

RESULTS

At 6 months corrected age, pre-term infants had significantly delayed P2 peak times than full-term infants (mean difference: 10.88 [95% CI 4.00-17.76] ms, p = 0.005). Pre-term infants also showed significantly reduced P2 amplitudes as compared to full-term infants (mean difference: 2.36 [0.83-3.89] µV, p = 0.003). Although the regression model with GA and BW as fixed factors explained 20% of the variance in the P2 peak time (F_2,47 = 5.98, p = .0045), only GA showed a significant negative relationship (β = -2.66, p = .003). Neither GA (β = 0.21, p = .28) nor BW (β = 0.001, p = .32) showed any relationship with P2 amplitude.

CONCLUSIONS

Our results demonstrate that, compared with full-term infants, clinically stable pre-term infants exhibit abnormal flash VEPs, with a delay in P2 peak time and a reduction in P2 amplitude. These findings support a potential dysfunction of the visual pathway in clinically stable pre-term infants as compared to full-term infants.

‘State-of-the-Art’ Neonatal Cranial Ultrasound

Cranial ultrasound (cUS) provides bedside imaging access to the neonatal brain. Modern scanners and the use of various acoustic windows give detail not only of the well known pathologies met in the preterm infant, but also allow assessment of more subtle aspects of normal and abnormal brain growth and development. cUS is also very helpful in the early diagnosis of the many aetiologies of neonatal encephalopathy and seizures in the term infant and the subsequent monitoring of progress of hypoxic-ischaemic brain injury. Training issues in cUS need to be addressed.

Early amplitude-integrated electroencephalography predicts brain injury and neurological outcome in very preterm infants

Early amplitude-integrated electroencephalography (aEEG) has been widely used in term infants with brain injury to predict neurodevelopmental outcomes; however, the prognostic value of early aEEG in preterm infants is unclear. We evaluated how well early aEEG could predict brain damage and long-term neurodevelopmental outcomes in very preterm infants compared with brain imaging assessments. We found that severe aEEG abnormalities (p=0.000) and aEEG total score<5 (p=0.006) within 72 h after birth were positively correlated with white-matter damage, but aEEG abnormalities were not associated with intracranial hemorrhage (p=0.186). Severe abnormalities in aEEG recordings, head ultrasound, and cranial magnetic resonance imaging (MRI) were all positively correlated with poor outcome at 18 months corrected age. The predictive power of poor outcomes of the aEEG and MRI combination was the same as the aEEG, MRI, and head ultrasound combination with a sensitivity of 52.4%, specificity of 96.2%, positive predictive value of 78.6%, and negative predictive value of 88.4%. These results indicate that severely abnormal aEEG recordings within 72 h after birth can predict white-matter damage and long-term poor outcomes in very preterm infants. Thus aEEG can be used as an early marker to monitor very preterm infants.

Mortality and major morbidities in very preterm infants born from assisted conception or naturally conceived: results of the area-based ACTION study

BACKGROUND

The use of assisted conception (AC) has been associated with higher risk of adverse perinatal outcome. Few data are available on the outcome of AC-neonates when pregnancy ends before 32 weeks of gestational age.The aim of this study was to compare the short-term outcome of AC- and naturally conceived preterm infants <32 weeks gestation.

METHODS

The area-based cohort study ACTION collected data on births 22-31 weeks gestation occurred in 2003-05 in 6 Italian regions. Infants born to 2529 mothers with known mode of conception were studied. The main outcomes were hospital mortality and survival free from major morbidities (IVH grade 3-4, cPVL, ROP stage ≥3, BPD), and were assessed separately for single and multiple infants. Other outcomes were also investigated. Multivariable logistic analyses were used to adjust for maternal and infants' characteristics. To account for the correlation of observations within intensive care units, robust variance and standard error estimates of regression parameters were computed.

RESULTS

AC was used in 6.4% of mothers. Infants were 2934; 314 (10.7%) were born after AC. Multiples were 86.0% among AC and 21.7% among non-AC babies. In multivariable analysis no statistically significant difference in hospital mortality and survival without major morbidities was found between AC and non-AC infants. The risk of BPD was lower in AC than in non-AC multiples (aOR 0.41, CI 0.20-0.87), and this finding did not change after controlling for mechanical ventilation (aOR 0.42, CI 0.20-0.85) or presence of a patent ductus arteriosus (aOR 0.39, CI 0.18-0.84).

CONCLUSION

When the analysis is restricted to very preterm infants and stratified by multiplicity, no significant associations between AC and increased risk of short-term mortality and survival without major morbidities emerge. This result is consistent with previous studies, and may confirm the hypothesis that the adverse effects of AC are mediated by preterm birth. However, larger appropriately powered studies are needed before definitely excluding the possibility of adverse events linked to AC in infants born before 32 weeks gestation.

Reduced occipital fractional anisotropy on cerebral diffusion tensor imaging in preterm infants with postnatally acquired cytomegalovirus infection

BACKGROUND

Detection of white matter (WM) abnormalities on MRI is important regarding the neurodevelopmental outcome in preterm infants. The long-term neurodevelopmental outcome of preterm infants with postnatal cytomegalovirus (CMV) infection has not been studied extensively.

OBJECTIVES

We aimed to assess WM microstructure in preterm infants with postnatal CMV infection using diffusion tensor imaging.

METHODS

Infants <32 weeks' gestational age (GA) admitted to our hospital between 2007 and 2010, who had cerebral diffusion tensor imaging at term-equivalent age (40 weeks' GA) were included. CMV PCR in urine collected at term-equivalent age was performed to diagnose postnatal CMV infection. Congenital infection was excluded. In the frontal, parietal and occipital WM mean diffusivity, fractional anisotropy (FA), radial and axial diffusivity were calculated. Neurodevelopmental outcome was assessed at 16 months' corrected age using Griffiths' Mental Developmental Scales.

RESULTS

Twenty-one postnatally infected and 61 noninfected infants were eligible. Both groups were comparable regarding GA, birth weight and age at MRI. There was a significant difference in median FA of the occipital WM between infected and noninfected infants (0.13 [IQR 0.11-0.16] versus 0.16 [IQR 0.14-0.18], p = 0.002). There were no differences in short-term neurodevelopmental outcome between infected and noninfected infants.

CONCLUSIONS

A significantly reduced FA suggests microstructural changes in the occipital WM of postnatally infected infants. These microstructural changes do not appear to result in impaired neurodevelopmental outcome at 16 months' corrected age.

Correlation between a semiautomated method based on ultrasound texture analysis and standard ultrasound diagnosis using white matter damage in preterm neonates as a model

OBJECTIVES

Diagnosis of white matter damage by cranial ultrasound imaging is still subject to interobserver variability and has limited sensitivity for predicting abnormal neurodevelopment later in life. In this study, we evaluated the ability of a semiautomated method based on ultrasound texture analysis to identify patterns that correlate with the ultrasound diagnosis of white matter damage.

METHODS

The study included 44 very preterm neonates born at a median gestational age of 29 weeks 3 days (range, 26 weeks-31 weeks 6 days). Patients underwent cranial ultrasound scans within 1 week of birth and between 14 and 31 days of life. Periventricular leukomalacia was diagnosed by experienced clinicians on the 14- to 31-day scan according to standard criteria. To perform the texture analysis, 4 regions of interest were delineated in stored images: left and right periventricular areas and choroid plexuses. A classification algorithm was developed on the basis of the best combination of texture coefficients to correlate with the clinical diagnosis, and the ability of this algorithm to predict a later diagnosis of periventricular leukomalacia on the first scan was evaluated using a leave-one-out cross-validation.

RESULTS

Periventricular leukomalacia was diagnosed by the standard procedure in 14 of 44 neonates. The texture classification algorithm performed on the first scan could identify cases with a later diagnosis of periventricular leukomalacia with sensitivity of 100% and accuracy of 97.7%.

CONCLUSIONS

These data support the notion that semiautomated quantitative ultrasound analysis achieves early identification of changes in subclinical stages and warrant further investigation of the role of ultrasound texture analysis methods to improve early detection of neonatal brain damage.

Somatosensory evoked potentials in children with bilateral spastic cerebral palsy

Alterations were monitored of somatosensory evoked potentials in children with bilateral spastic cerebral palsy and these findings correlated with relevant clinical and laboratory parameters. Fifty-one children with bilateral spastic cerebral palsy (31 boys, 20 girls; age range 24-168 months) participated in the study. Abnormal somatosensory evoked potentials latencies were recorded in 23 of 34 (67.6%) cortical recordings of the median nerve and in 38 of 51 (74.5%) cortical recordings of the tibial nerve. Abnormal tibial nerve somatosensory evoked potentials were strongly correlated with abnormal electroencephalogram (P=0.014), while impaired median nerve recordings were correlated with abnormal visual evoked potentials (P = 0.02) and a history of perinatal or neonatal infection (P=0.016). Furthermore, perinatal/neonatal infection adversely effected the recordings in both tibial and medial nerves in quadriplegic patients (P=0.023). Sensory impairment is strongly related with abnormal visual evoked potentials, abnormal electroencephalogram, and a history of perinatal or neonatal infection.

Predictability of cerebral palsy and its characteristics through neonatal cranial ultrasound in a high-risk NICU population

The aim of the study is to evaluate the predictive value of various types of brain injury detected by ultrasound in the neonatal period for the occurrence of cerebral palsy and its characteristics in a large cohort of high-risk infants. Thousand twenty-one consecutively NICU-admitted high-risk infants were assessed up to the corrected age of at least 2 years. Cerebral palsy (CP) was categorised into spastic or non-spastic, bilateral or unilateral and mild, moderate or severe CP. Different types of brain injury were identified by serial cranial ultrasound (US) during the NICU stay: white matter disease (WMD), haemorrhage, cerebral infarction, deep grey matter and parasagittal cerebral injury. There is a significant overall association between different types of brain injury and gestational age. Only 4% of the children with normal US develop CP. In the presence of any abnormal US image, the likeliness to develop CP is at least seven times higher. Within the group of infants with WMD and haemorrhage, the degree of brain involvement has a clear impact on the occurrence of CP. Concerning the characteristics of CP, deep grey matter lesion predict non-spastic CP versus spastic CP (OR = 31, P < 0.001). Cerebral infarction and haemorrhage grade IV are strong predictors of unilateral spastic CP versus bilateral spastic CP (OR = 49 and 24, respectively, P < 0.001). Deep grey matter lesion is a significant predictor for severe versus mild and moderate CP (OR = 6). In conclusion, neonatal cranial US is a useful tool in predicting CP and its characteristics.

Fetal neurological assessment using noninvasive magnetoencephalography

SQUID Array for Reproductive Assessment is a unique magnetoencephalography device designed for the noninvasive recording of fetal brain activity. In this article, we provide a general overview of the technology and its potential application to fetal medicine. A large number of studies that have been conducted and published describing this device since it was brought into operation are referenced throughout the article.

Frequently encountered cranial ultrasound features in the white matter of preterm infants: correlation with MRI

BACKGROUND

Bilateral symmetrical echogenic and echolucent areas in the white matter are frequently seen on the cranial ultrasound scans of apparently well preterm infants without overt pathology.

AIM

To determine whether these features reflect maturational processes as seen on MRI.

METHODS

Preterm and term-born infants without overt pathology on contemporaneous brain ultrasound and MRI were studied. Ultrasound scans were compared with T(2)-weighted MRI to identify MR correlates for the bilateral and symmetrical echogenic and echolucent phenomena in the white matter seen on ultrasound.

RESULTS

Forty-four sets of scans (26 preterm, 8 term-born infants) were assessed. Echogenic features were better and more frequently seen on early ultrasound as compared to nearer term age. Echogenic blushes in the white matter correlated well with high signal intensity areas and echogenic lines with low signal intensity lines on MRI. Echolucent areas correlated with the site of the internal capsule and the myelinated posterior pons. The subplate was not reliably identified.

CONCLUSION

Many echogenic and echolucent features in the white matter of well preterm and some term-born infants correlated well with areas of differing signal intensity on MRI. They most likely reflect normal maturational processes but the echogenic hemispheric features may represent delayed or abnormal maturation.

Predictive values of cranial ultrasound and assessment of general movements for neurological development of preterm infants in the Maribor region of Slovenia

OBJECTIVE

The aim of the study was to assess the predictive values of cranial ultrasound (US) scans and assessment of general movements of fidgety character (GMs) for the later neurological development of preterm infants in the Maribor region of Slovenia.

METHODS

Results of cranial US scans done longitudinally from the day of birth until the end of three months of chronologic age and results of GMs at three months of corrected age were compared with traditional neurological examination and evaluation of psychomotor development of the same children at the corrected age of six years.

RESULTS

A total of 112 preterm infants (gestational age 37 weeks and below) were included in the study. The infants were classified as low-risk or high-risk for neurological impairment on the basis of cranial US scans. The scans classified as low-risk were followed by a normal neurological outcome in 74 (89%) of 83 infants; those classified as high-risk for neurological impairment were followed by abnormal neurological outcome in 21 (72%) of 29 infants. Of 77 infants with normal fidgety movements, 73 (95%) had a normal neurological outcome and 4 (5%) had an abnormal neurological outcome; of 35 infants with abnormal or absent fidgety movements, 26 (74%) had an abnormal neurological outcome and 9 (26%) had a normal neurological outcome. Of 30 children with abnormal outcome, cerebral palsy was diagnosed in 16, mental retardation in one, nine children had both of these, and four had complex minor neurological dysfunction. The validity of the scans was 85%, sensitivity 70%, specificity 90%, positive predictive value 72% and negative predictive value 89%; the validity of the GMs was 88%, sensitivity 87%, specificity 89%, positive predictive value 74% and negative predictive value 95%.

CONCLUSIONS

The sensitivity of the cranial US scans was clearly lower than that of assessment of general movements of a fidgety character. The specificities of the two methods were almost the same.

Long-term outcome of preterm infants treated with nasal continuous positive airway pressure

This study's aim was to assess neurodevelopmental and growth outcome until the age of 4 years of premature infants placed on early nCPAP, in the setting of the neonatal intensive care unit (NICU) and follow-up program of the Division of Neonatology of the Department of Pediatrics of the University Hospital, Lausanne, Switzerland. All consecutive inborn infants weighing <1500 g or <32 weeks of gestational age admitted to the NICU during two periods of 12 months-7.1996-6.1997 and 7.1998-6.1999-were compared before and after the systematic application of early nCPAP. Of 172 infants admitted to the NICU, 150 (87%) survived. 126 (84%) were tested at 6 months' corrected age, 121 (81%) at 18 months' corrected age, and 117 (78%) at the age of 4 years. Detailed perinatal data were collected. Follow-up included neurological examination, developmental testing and measurement of growth parameters. Statistical analyses were performed. Early application of nCPAP and avoidance of mechanical ventilation showed no adverse effects on neurodevelopment and growth. A significantly higher developmental quotient was found in the nCPAP group at 18 months' corrected age. Several trends were also noted in the nCPAP group with a decrease of intraventricular hemorrhage and in "abnormal neurodevelopment" at 6 months corrected age, a bigger head circumference at all different tested ages and a greater height at 6 and 18 months corrected ages. In conclusion, our study of developmental outcome documents the absence of any harmful effect of early application of nCPAP to treat respiratory failure in very low birthweight infants.

The role of magnetic resonance imaging in elucidating the pathogenesis of cerebral palsy: a systematic review

The aim of this study was to show the role of magnetic resonance imaging (MRI) in elucidating the aetiology, or at least pathogenesis, of cerebral palsy (CP). A systematic review of studies using MRI in children with CP was performed according to pathogenetic patterns characterizing different timing periods of occurence of the lesions, and with respect to gestational age (term vs preterm) and CP subtypes. Out of the studies published since 1990 in English, six met all the inclusion criteria; they involved children with spastic and dyskinetic CP. Abnormal MRI was reported in 334 out of 388 (86%) patients and gave clues to pathogenesis in 83%. Fourteen studies met only part of the inclusion criteria and abnormal MRIs were reported even more frequently in these (91%; 930/1022). Periventricular white matter lesions were most frequent (56%) followed by cortical and deep grey matter lesions (18%); brain maldevelopments were rather rare, described in 9%. Brain maldevelopments and grey matter lesions were more often seen in term than in preterm-born children with CP (brain maldevelopments: 16% vs 2.5%; grey matter lesions: 33% vs 3.5%); periventricular white matter lesions occurred significantly more often in preterm than in term-born children (90% vs 20%). CP is mainly characterized by brain lesions which can be identified by MRI in around 75% of preterm infants; brain maldevelopments occur in around 10%.

Population cohort associating chorioamnionitis, cord inflammatory cytokines and neurologic outcome in very preterm, extremely low birth weight infants

Intrauterine inflammation may relate to neurologic disability among preterm children. We investigated the relationship between chorioamnionitis, cord serum cytokines, and neurologic outcome. Sixty-one consecutively born very preterm extremely low birth weight (ELBW) infants were prospectively enrolled. Histologic inflammation in placenta and umbilical cord and vascular pathology were evaluated. Cord sera were analyzed for five proinflammatory cytokines. Serial brain ultrasound and magnetic resonance imaging were performed for evaluation of intraventricular hemorrhage (IVH grade I-III) and white matter damage (WMD: cystic periventricular leukomalacia or IVH grade IV). Neurologic and neurocognitive outcomes were assessed at the corrected age of 2 y. The incidences of HCA, WMD, and abnormal neurologic outcome were 48%, 13% and 19%, respectively. HCA or high IL-6 in cord serum predicted spontaneous preterm labor with high accuracy. HCA increased the risk of IVH grade II-III. In HCA, without either clinical chorioamnionitis or histologic placental perfusion defect, the children had a low risk of WMD (0%) and a low risk of abnormal neurologic outcome (6%). In HCA, the concentration of IL-6 in cord serum was lower in children with abnormal neurologic outcome than in children with normal neurologic outcome. In HCA and placental perfusion defect (compound defect) the risk of abnormal neurologic outcome was high. Compound placental defect and WMD additively predicted abnormal neurologic outcome. We propose that HCA together with other insults (placental perfusion defect or maternal systemic infection) increases the risk of poor neurologic outcome in very preterm ELBW infants.

Suboptimal neurodevelopment in very preterm infants is related to fetal cardiovascular compromise in placental insufficiency

OBJECTIVE

The purpose of this study was to determine the relationship between fetal cardiovascular hemodynamics and neurodevelopmental outcome in infants born before 32 gestational weeks with placental insufficiency.

STUDY DESIGN

Seventeen fetuses that underwent Doppler ultrasonography within 24 hours before delivery were included in this prospective cross-sectional study. Placental histology was examined. Multiple inflammatory markers and vascular endothelial growth factor (VEGF) and its receptor were analyzed from umbilical cord serum. Neurodevelopmental outcome was assessed by Griffiths scales at 1 year of corrected age.

RESULTS

Infants with suboptimal outcome (n = 7) had higher umbilical artery, ductus venosus, and inferior vena cava pulsatility index values (P < .05) and lower weight-indexed cardiac outputs (P < .05) than infants with normal outcome (n = 10). Placental histology and serum revealed no inflammation. VEGF values were similar among all infants.

CONCLUSION

In placental insufficiency with delivery before 32 gestational weeks, suboptimal neurodevelopment was related to decreased fetal weight-indexed cardiac output and increased systemic venous pressure.

Imaging of early brain injury and cortical plasticity

The human brain undergoes complex organizational changes during development in and ex utero. Pathogenic events affecting the developing brain cause abnormalities or lesions, the patterns of which depend on the stage of brain development. During the first and second trimester, cortical neurogenesis predominantly takes place, characterized by proliferation, migration, and organization of neuronal cells. Brain pathology is characterized by maldevelopments. During the third trimester, growth and differentiation events are predominant, which persist into postnatal life. Disturbances of brain development during this period mainly cause lesions. During the early third trimester, periventricular white matter is especially affected, whereas toward the end of the third trimester, gray matter, either cortical or deep gray matter, appears to be more vulnerable. These patterns of brain maldevelopments or lesions offer excellent models to study mechanisms of organization and reorganization in the developing brain. Evidence for superior brain plasticity is well established for language function after early left-sided lesions. Some evidence exists for higher compensatory potential within in the motor system; maintenance of ipsilateral tracts seems to play a certain, but only incomplete functional role after unilateral lesions in early and mid gestation. The visual system seems to have limited compensatory potential.

Obstetric risk factors and persistent increases in brain parenchymal echogenicity in preterm infants

OBJECTIVE

To assess the risk of persistent (>7 days) increases in brain parenchymal echogenicity in preterm infants and their association with known obstetric risk factors.

DESIGN

Case-control study of prospectively collected data.

SETTING

A University hospital in Northern Italy.

POPULATION

Eighty-five singleton infants between 24 and 34 weeks of gestation with a cranial ultrasonographic diagnosis of persistently increased parenchymal echogenicity without development of cystic degeneration, and 170 control infants with negative cranial ultrasonographic findings.

METHODS

A comparison of the prevalence of selected obstetric risk factors between infants with persistent echo-dense lesions and negative controls.

MAIN OUTCOME MEASURES

Odds ratios of persistent echo-dense lesions including first-degree interactions between variables.

RESULTS

After adjusting for birthweight, logistic regression analysis showed that the only factor associated with an increased risk of persistent brain echo-dense lesions in infants was multiple courses of antenatal steroids (OR = 2.14, 95% CI = 1.11-4.15, P= 0.024). In this group, the risk of persistent echo-dense lesions was particularly high in: (i) mothers receiving dexamethasone rather than betamethasone (P value for interaction = 0.015) and (ii) after expectant management of pre-eclampsia or intrauterine growth retardation (P value for interaction = 0.03).

CONCLUSIONS

Multiple doses of antenatal steroids, especially dexamethasone, could influence the prevalence of persistent increases in brain parenchymal echogenicity in preterm infants.

MRI measurements of the pons and cerebellum in children born preterm; associations with the severity of periventricular leukomalacia and perinatal risk factors

Our purpose was to measure the size of the pons and cerebellum in preterm babies with periventricular leukomalacia (PVL), and to study their relationship with the severity of PVL and with perinatal risk factors. We examined 33 premature children, mean gestational age 31 weeks, range 26-36 weeks with PVL on MRI, and 27 full-term controls. On MRI at 0.4-5.5 years (mean 1.4 years) we measured the area of the corpus callosum and vermis, the anteroposterior diameter of the pons and the volume of the cerebellum. The area of the corpus callosum was used as a marker of white matter loss and PVL severity. All regional brain measurements except that of the vermis were significantly lower in patients than controls: corpus callosum (mm(2)): 239.6+/-92.5 vs 434.8+/-126.8, P <0.01; pons (mm): 14.8+/-3.0 vs 17.9+/-1.4, P <0.01]; cerebellum (cm(3)): 68.2+/-31.6 vs 100.6+/-28.3, P <0.01; vermis (mm(2)): 808.1+/-292.2 vs 942.2+/-246.2, NS. Significant reduction in the area of the vermis: 411.3+/-203.3 vs 935+/-252.6 mm(2); cerebellar volume: 16.3+/-12.5 vs 96.6+/-20.2 mm(3); and the diameter of the pons: 10.1+/-2.2 vs 17.5+/-1.3 mm ( P<0.01) were observed in seven children with gestational age < or =28 weeks, severe hypotension and large patent ductus arteriosus (PDA). There was a significant correlation between the duration of mechanical ventilation and the size of the vermis, pons and cerebellum (R=-0.65, -0.57 and -0.73, respectively, P <0.01).

Perinatal risk factors for adverse neurodevelopmental outcome after spontaneous preterm birth

OBJECTIVE

The aim of this study was to investigate to what extend perinatal factors contribute to the neurodevelopmental outcome in a group neonates born after spontaneous preterm labour with or without prolonged rupture of the membranes (PROM).

METHODS

In a cohort of neonates born after the spontaneous onset of labour with or without PROM before 34 weeks of gestation a stepwise forward logistic regression was performed to analyse the influence of antenatal and postnatal variables on adverse outcome. Adverse neurodevelopmental outcome was defined as a Griffith's developmental score <85, cerebral palsy, a major disability or perinatal death associated with severe cerebral damage.

RESULTS

The study group consisted of 185 neonates. Seven neonates died with severe cerebral damage. After a forward logistic regression analysis three factors appeared to have an independent influence: gestational age protected against an adverse outcome (odds ratio (OR) per day increase 0.95, 95% confidence interval (CI) 0.90-0.97) while abnormal cranial ultrasound (intraventricular haemorrhage and periventricular leucomalacia) (OR 6.33, 95% CI 2.16-18.52) and the need for a second course of antibiotics (OR 1.85, 95% CI 1.02-3.33) increased the risk for adverse outcome. Comparing the group with a normal neurodevelopmental outcome with those with cerebral palsy, cranial ultrasound abnormalities were independently associated with cerebral palsy (OR 48.75, 95% CI 11.78-201.76).

CONCLUSION

The most important way of preventing neurological damage in infants is to increase gestational age at birth and to avoid the development of intraventricular haemorrhage and periventricular leucomalacia.

Perinatal risk factors for cranial ultrasound abnormalities in neonates born after spontaneous labour before 34 weeks

OBJECTIVE

The aim of this study was to identify risk factors for cranial ultrasound abnormalities in neonates born after spontaneous preterm labour with or without prolonged premature rupture of the membranes (PROM).

METHODS

The presence of intraventricular haemorrhage and cystic periventricular leucomalacia was investigated in a cohort of neonates born between 24 and 34 weeks using cranial ultrasound. A stepwise forward logistic regression was performed to analyse the influence of antenatal and postnatal variables on cranial ultrasound abnormalities.

RESULTS

The study group consisted of 205 neonates and cranial ultrasound abnormalities were identified in 27 infants. Early onset neonatal infectious disease (OR 3.09, 95% CI 1.24--7.70, P=0.01) increased the risk for cranial ultrasound abnormalities. Gestational age at birth (OR 0.96, 95% CI 0.93--0.99, P=0.03) and a full course of antenatal steroids (OR 0.33, 95% CI 0.13--0.85, P=0.02) reduced the risk for cranial ultrasound abnormalities.

CONCLUSION

Early onset neonatal infectious disease is an independent risk factor for cranial ultrasound abnormalities in the very preterm neonate born after spontaneous labour with or without PROM.

Adaptive mechanisms of developing brain. The neuroradiologic assessment of the preterm infant

Since the 1980s, cranial sonography has been routinely performed in premature infants. This has produced a wealth of information about the more dramatic central nervous system lesions of IVH, PVL, and late VM. This information has included timing and evolution of these lesions and their eventual correlation with outcome. For two reasons the advent of MR imaging scanning has produced an interest in using this modality to evaluate these same infants. First, MR imaging gives an obviously superior image, and its ability to detect lesions is far superior to that of ultrasound. Second, the ability of cranial sonography to detect all of the children with CP or low IQ is limited. In our studies of outcome in very low-birth weight infants grade 3 to 4 IVH, PVL, or VM are able to detect only about 50% of the infants who developed CP by 3 years. This condition should be highly correlated with structural brain disease; an imaging modality that was more sensitive to central nervous system lesions should offer an advantage in predicting outcome. In the only prospective assessment of the ability of these two modalities to predict outcome at 3 years, van de Bor and colleagues found MR imaging did not do better than cranial sonography. This was largely because both modalities detected the most severe lesions, and most children with milder lesions on MR imaging had normal outcome. Studies of late (age 1 to teenage years) MR imaging scans in preterm infants show that a high percentage have white matter lesions but these lesions correlate poorly with outcome. If our concern when counseling parents is to alert them when a serious adverse outcome is likely in their child, then cranial sonography is to be favored precisely because it is less able to detect subtle lesions, which the developing brain has the capacity to overcome. On the other hand, if our aim is to detect all lesions, even though these lesions do not predict serious adverse outcomes, then MR imaging is to be favored. Research aimed at discovering etiologies and mechanisms of brain injury in these high-risk infants should use the more sensitive modality MR imaging. Finally, the interesting observation that preterm infants fare as well as they do despite MR imaging-identified lesions might stimulate research studying the adaptive mechanisms of developing brain.

Antenatal glucocorticoid treatment and cystic periventricular leukomalacia in very premature infants

BACKGROUND

Antenatal glucocorticoid therapy decreases the incidence of several complications among very premature infants. However, its effect on the occurrence of cystic periventricular leukomalacia, a major cause of cerebral palsy, remains unknown.

METHODS

We retrospectively analyzed a cohort of 883 live-born infants, with gestational ages ranging from 24 to 31 weeks, who were born between January 1993 and December 1996 at three perinatal centers in the Paris area. The mothers of 361 infants had received betamethasone before delivery, the mothers of 165 infants had received dexamethasone before delivery, and the mothers of 357 infants did not receive glucocorticoids. We compared the rates of cystic periventricular leukomalacia among the three groups of infants in bivariate and multivariate analyses after adjustment for confounding factors.

RESULTS

The rate of cystic periventricular leukomalacia was 4.4 percent among the infants whose mothers had received betamethasone, 11.0 percent among the infants whose mothers had received dexamethasone, and 8.4 percent among the infants whose mothers had not received a glucocorticoid. After adjustment for gestational age, the mode of delivery, and the presence or absence of chorioamnionitis, prolonged interval between the rupture of membranes and delivery (>24 hours), preeclampsia, and the use of tocolytic drugs, antenatal exposure to betamethasone was associated with a lower risk of cystic periventricular leukomalacia than was either the absence of glucocorticoid therapy (adjusted odds ratio, 0.5; 95 percent confidence interval, 0.2 to 0.9) or exposure to dexamethasone (adjusted odds ratio, 0.3; 95 percent confidence interval, 0.1 to 0.7). The adjusted odds ratio for the group of infants whose mothers had received dexamethasone as compared with the group of infants whose mothers had not received a glucocorticoid was 1.5 (95 percent confidence interval, 0.8 to 2.9).

CONCLUSIONS

Antenatal exposure to betamethasone but not dexamethasone is associated with a decreased risk of cystic periventricular leukomalacia among very premature infants.

Amniotic fluid concentrations of interleukin-1beta, interleukin-6 and TNF-alpha in chorioamnionitis before 32 weeks of gestation: histological associations and neonatal outcome

OBJECTIVES

To test the association between cytokine levels in the amniotic fluid and (i) the vascular invasion phase of intrauterine infection, (ii) the occurrence of periventricular leukomalacia; to assess the correlation between C-reactive protein levels, a recognised biological marker of inflammation in maternal serum and cytokine levels in the amniotic fluid.

DESIGN

Prospective clinical study.

SETTING

Fetal medicine unit and neonatal intensive care unit, Antoine Beclere Hospital, Clamart, France.

SAMPLE

Thirty-one pregnancies complicated by chorioamnionitis leading to birth before 32 weeks of gestation.

METHODS

Interleukin 1-beta, Interleukin 6 and TNF-alpha prospectively measured in the amniotic fluid. Histological examination of the placenta. Ultrasound examination and magnetic resonance imaging of the brains of the newborn infants performed within the first week of life.

MAIN OUTCOME MEASURES

The occurrence of periventricular leukomalacia was assessed by transfontanellar ultrasound and magnetic resonance imaging.

RESULTS

There was a significant positive correlation between the occurrence of histological chorioamnionitis, vascular extension of infection of the membranes, maternal inflammatory syndrome and neonatal sepsis. A strong association was found between maternal serum C-reactive protein concentrations and cytokine levels in the amniotic fluid. Interleukin-1beta was the best predictor of vascular extension of chorioamnionitis, and TNF-alpha was the best predictor of the development of severe early neonatal infection. There was no association between the amniotic fluid levels of cytokines and the development of periventricular leukomalacia.

CONCLUSIONS

These data suggest that IL-1beta, IL-6 and TNF-alpha are produced in relation to intrauterine inflammation and infection, but cannot be directly implicated in the development of fetal cerebral white matter lesions.

Visual, cognitive, and neurodevelopmental outcome at 51/2 years in children with perinatal haemorrhagic-ischaemic brain lesions

To determine predictive values of early visual and neurocognitive assessment in children with perinatally acquired haemorrhagic or ischaemic brain lesions selected on the basis of ultrasound, 63 children (37 boys, 26 girls), who had been followed and examined until the age of 18 months, were reexamined at 5 1/2 years. Good correlations between visual and neurodevelopmental assessments at 18 months and at 5 1/2 years were found. When ultrasound abnormalities were combined with early visual and neurocognitive assessment data, good predictive values, especially for the group of children who had grade 2 to 4 leukomalacia, were found for visual acuity and neurodevelopment.

The early diagnosis of periventricular leukomalacia in premature infants with positive rolandic sharp waves on serial electroencephalography

OBJECTIVE

The objective of this study was to determine the specificity and the sensitivity of electroencephalography's positive rolandic sharp waves (PRSW) for the diagnosis of cystic and noncystic periventricular leukomalacia (PVL).

METHODS

A retrospective study was performed on a population of 765 premature infants alive after 5 days who were divided into two groups; 166 infants born before 28 weeks (group 1) and 599 born between 28 and 32 completed weeks' gestation (group 2). Each infants underwent repeated ultrasound scanning and electroencephalography recordings during the first weeks of life. Magnetic resonance imaging was performed in infants with persisting hyperechoic periventricular densities on ultrasonography.

RESULTS

A total of 83 (10.8%) newborns had PVL; 65 (8.5%) had cystic PVL PRSW, observed in 55 (7.2%) infants, always preceded the ultrasonic detection of cysts. PRSW were very specific markers of PVL in both groups (100% in group 1, 99.8% in group 2). PRSW sensitivity was found dependent on gestational age: 32.4% in group 1 in contrast to 87.8% in group 2.

CONCLUSION

PRSW are an early and very specific marker of PVL in premature infants.