Prediction of outcome at school age in neonatal intensive care unit graduates using neonatal neurologic tools

Continuous positive airway pressure treatment may negatively affect auditory maturation in preterm infants

AIM

Nasal continuous positive airway pressure (CPAP) devices generate loud noise, which might harm auditory function and maturation. The function of auditory pathways can be examined by using brainstem auditory evoked potential (BAEP) and brainstem audiometry (BA) recordings. Our objective was to study whether CPAP treatment during the neonatal period is associated with abnormalities in BAEP and BA recordings.

METHODS

Included in this retrospective study were preterm infants (birth weight ≤1500 g and/or gestational age ≤32 weeks) born between 2002 and 2006 with a comprehensive clinical background and follow-up data, including the duration of CPAP treatment (n = 162). BAEP and BA were recorded near the mean corrected age of one month. The following variables from BAEP and BA examinations were analysed: latencies of BAEP components I, III, V, interpeak intervals (IPI) I-V, I-III, III-V (ms), amplitude I and V (µV), amplitude ratio I/V and BA thresholds.

RESULTS

In the adjusted analysis, a longer CPAP treatment leads to longer latencies of BAEP component III (p = 0.01) and V (p = 0.02) in the right ear.

CONCLUSION

CPAP treatment may impair the auditory maturation and processing mediated via the dominant right ear. The hearing and neurodevelopment of the children who are treated with CPAP should be followed.

Impact of prematurity on neurodevelopment

The consequences of prematurity on brain functional development are numerous and diverse, and impact all brain functions at different levels. Prematurity occurs between 22 and 36 weeks of gestation. This period is marked by extreme dynamics in the physiologic maturation, structural, and functional processes. These different processes appear sequentially or simultaneously. They are dependent on genetic and/or environmental factors. Disturbance of these processes or of the fine-tuning between them, when caring for premature children, is likely to induce disturbances in the structural and functional development of the immature neural networks. These will appear as impairments in learning skills progress and are likely to have a lasting impact on the development of children born prematurely. The level of severity depends on the initial alteration, whether structural or functional. In this chapter, after having briefly reviewed the neurodevelopmental, structural, and functional processes, we describe, in a nonexhaustive manner, the impact of prematurity on the different brain, motor, sensory, and cognitive functions.

Neural correlates of early adversity among Bangladeshi infants

In this paper we explore the relationship between the Visual Evoked Potential (VEP), a component of the electroencephalogram elicited by visual stimuli, and cognitive functions in children growing up in an urban slum in Bangladesh. VEPs in response to pattern-reversing checkerboards were collected in 6 month-old-infants (n = 91) and 36-month-old children (n = 112). We examine variation in the amplitude and latency of the first positive component, the P1, of the VEP in relation to cognitive scores on the Mullen Scales of Early Learning and the Wechsler Preschool and Primary Scale of Intelligence. We also examine whether children’s caregiving experiences prior to the neuro-cognitive assessment explain variation in the P1 of the VEP. We find that the P1 amplitude of the VEP is related to concurrent cognitive performance in each respective cohort. We also find that the P1 amplitude at 6 months is prospectively associated with cognitive outcomes at 27 months, and the P1 amplitude at 36 months is prospectively associated with children’s IQ at 60 months. We find no associations between caregiving experiences and variation in the P1 of the VEP at 6 months, yet caregiving experience do explain variation in the P1 amplitude at 36 months. Caregiving experiences also explain variation in children’s concurrent and prospective cognitive functioning. The VEP may be used as a biomarker to index the neurobiological embedding of early adversity, which in turn may impact children’s cognitive functions.

Developmental care, neonatal behavior and postnatal maternal depressive symptomatology predict internalizing problems at 18 months for very preterm children

OBJECTIVE

To provide a prospective developmental model for behavioral outcomes in preterm infants in relation to developmental care (DC) practices and postnatal maternal depression.

STUDY DESIGN

A longitudinal, multicenter, follow-up study conducted in 25 Italian tertiary neonatal intensive care units (NICUs). Participants were 162 healthy very preterm infants and their mothers. The level of quality of DC was assessed for each hospital. Infant's neurobehavioral profile was evaluated twice: at discharge (T1) and at 18 months for behavioral problems (T3). Maternal depressive symptomatology was measured at T1 and at 6 months (T2).

RESULTS

Low-quality DC in NICUs was associated with lower levels of infant neurobehavioral adaptability and higher levels of maternal depressive symptoms. Maternal depressive symptomatology in conjunction with higher infant dysregulation predicted more internalizing problems at 18 months of age.

CONCLUSION

DC interventions and postnatal maternal depression, as well as infant behavior have an impact on short- and long-term infant outcomes.

Neural conduction impairment in the auditory brainstem and the prevalence in term babies in neonatal intensive care unit

OBJECTIVE

To detect neural conduction abnormality in the auditory brainstem in term babies in the neonatal intensive care unit (NICU), determine prevalence of the abnormality, and assess if maximum length sequence (MLS) technique improves early detection of the abnormality.

METHODS

One hundred and six term babies were recruited, and studied by recording and analysing MLS brainstem auditory evoked response (BAER). Interpeak intervals were analysed in detail, which were then compared with those in normal term babies.

RESULTS

Wave V latency and I-V and III-V intervals in MLS BAER were increased in the NICU term babies at all click rates 91-910/s, particularly at 455 and 910/s (p<0.05-0.001). No major abnormalities were found in wave I and III latencies and I-III interval. The abnormal increase in I-V and III-V intervals were seen in significantly more cases at 455 and 910/s in MLS BAER than at 21/s in conventional BAER (X(2)=10.92-13.88, all p<0.01). As a whole, 38 (35.8%) of the NICU babies had abnormal III-V and/or I-V intervals in MLS BAER, which was significantly more than 13 (12.2%) in conventional BAER (X(2)=16.14, p<0.01).

CONCLUSION

There is neural conduction impairment in the auditory brainstem in NICU term babies, which occurs in one-third of these babies.

SIGNIFICANCE

Term babies in NICU are at risk of neural conduction impairment in the auditory brainstem. High click rates in MLS BAER enhance early detection of the impairment.

Brain volume and neurobehavior in newborns with complex congenital heart defects

OBJECTIVE

To investigate the relationship between tissue-specific alterations in brain volume and neurobehavioral status in newborns with complex congenital heart defects preoperatively.

STUDY DESIGN

Three-dimensional volumetric magnetic resonance imaging was used to calculate tissue-specific brain volumes and a standardized neurobehavioral assessment was performed to assess neurobehavioral status in 35 full-term newborns admitted to the hospital before cardiopulmonary bypass surgery. Multiple linear regression models were performed to evaluate relationships between neurobehavioral status and brain volumes.

RESULTS

Reduced subcortical gray matter (SCGM) volume and increased cerebrospinal fluid (CSF) volume were associated with poor behavioral state regulation (SCGM, P = .04; CSF, P = .007) and poor visual orienting (CSF, P = .003). In cyanotic newborns, reduced SCGM was associated with higher overall abnormal scores on the assessment (P = .001) and poor behavioral state regulation (P = .04), and increased CSF volume was associated with poor behavioral state regulation (P = .02), and poor visual orienting (P = .02). Conversely, acyanotic newborns showed associations between reduced cerebellar volume and poor behavioral state regulation (P = .03).

CONCLUSION

Abnormal neurobehavior is associated with impaired volumetric brain growth before open heart surgery in infants with complex congenital heart defects. This study highlights a need for routine preoperative screening and early intervention to improve neurodevelopmental outcomes.

Early prediction of cerebral palsy after neonatal intensive care using motor development trajectories in infancy

Neonatal intensive care unit (NICU) patients are at high risk for developmental disabilities such as cerebral palsy (CP). Early identification of CP is essential to effective rehabilitation, but diagnosis is often delayed, especially in preterm infants. We hypothesized that through the longitudinal evaluation of motor trajectories in the NICU follow-up clinic, we could distinguish infants who develop CP by 3 years of age.

STUDY DESIGN AND SUBJECTS

This was a retrospective study of 606 patients in the NICU Follow-up Clinic at Vanderbilt University with birth weight < 1500g or a diagnosis of hypoxic ischemic encephalopathy.

OUTCOMES MEASURES

Assessments included neurologic exams, the Developmental Assessment of Young Children (DAYC), the Bayley Scales of Infant Development (BSID) and the Gross Motor Function Classification Scale.

RESULTS

A decrease in DAYC scores between 6 and 12 months was present in preterm and term infants later diagnosed with CP, but not in children without CP (-23 vs. +1.5, p<0.001). DAYC score decreases in infancy were highly predictive of later CP (p<0.001). BSID scores quantified severe motor delays but did not add to prediction of CP diagnosis.

CONCLUSION

Standardized assessments of motor milestones quantitatively predict the risk of CP in former NICU patients by 12 months, allowing for timely diagnosis, counseling and therapy in high-risk infants.

Amplitude reduction in brainstem auditory response in term infants under neonatal intensive care

OBJECTIVE

To examine brainstem auditory electrophysiology in term neonates under intensive care due to perinatal conditions other than hypoxia-ischemia.

METHODS

Maximum length sequence brainstem auditory evoked response was studied in term neonates in an intensive care unit. The amplitudes of wave components of the response were analysed to assess brainstem auditory electrophysiology.

RESULTS

The amplitudes of all wave components in the neonates under intensive care tended to be smaller than in those in normal term controls. Wave I amplitude was significantly reduced at all 91-910/s clicks (p < 0.05-0.01). The amplitudes of waves III and V were also reduced, respectively, at 227-910/s (all p < 0.05) and at 455 and 910/s (both p < 0.01). The amplitude reduction was slightly more significant at higher than lower click rates, but there were no significant differences in the slopes of wave I, III and V amplitude-rate functions between the neonates under intensive care and the controls.

CONCLUSIONS

Wave amplitudes of maximum length sequence brainstem auditory evoked response were reduced in term neonates under intensive care due to perinatal conditions other than hypoxia-ischemia.

SIGNIFICANCE

Brainstem auditory electrophysiology is depressed in term neonates under intensive care, possibly due to collective adverse effects of perinatal conditions. The impairment to the neonatal, particularly rostral, brainstem due to other perinatal conditions is less severe than that due to hypoxia-ischemia previously reported.

Abnormal brain structure and function in newborns with complex congenital heart defects before open heart surgery: a review of the evidence

Newborns with complex congenital heart defects are at high risk for developing neurological abnormalities. It is important to understand the timing, progression, and extent of these abnormalities to better elucidate their potential impact on neurodevelopment, and their implications for early screening and intervention. This review synthesizes the recent literature describing neurological and neurobehavioral abnormalities observed in fetuses and newborns before cardiac surgery. A considerable proportion of newborns with complex congenital heart defects exhibit neurobehavioral and electrophysiological abnormalities preoperatively. Likewise, conventional neuroimaging studies reported that a high percentage of this population experienced brain injury. Advanced neuroimaging modalities indicated that fetuses showed delayed third trimester brain growth, and newborns showed impaired white matter maturation, reduced N-acetylaspartate, and increased lactate. These findings suggest a fetal or early postnatal onset of impaired brain growth and development. Consequently, reliable methods for early screening and subsequent developmental intervention must be implemented.

A Tool for Automatic Hammersmith Infant Neurological Examination

Hammersmith Infant Neurological Examination (HINE) is a popular method to estimate the neurological development of infants aged less than two years. Using HINE, especially for preterm or premature babies, the risk of neural disorder can be minimized through proper preventive measures. This paper presents the design of a semi-automatic application that can be used as an aid to doctors for efficiently conducting the examinations listed in the Hammersmith chart. The user friendly version of the examination interface provides a platform for quantitative neurological assessment of the infants. It includes various simplified video and image based schemes that are suited to inexperienced staff. It provides an interface to go through the previous records of patients. Ten examinations are enlisted in the Hammersmith chart for neonatal babies. This paper examines a semi-automatic approach for posture estimation examination. For post neonatal infants, a follow-up management interface is designed that can be used to fetch / consult past records of the patients for better diagnosis. The application is currently in operation at Neonatal Intensive Care Unit (NICU) of Institute of Post-Graduate Medical Education & Research (IPGME & R) and Seth Sukhlal Karnani Memorial (SSKM) Hospital, Kolkata, India.

Neonatal somatosensory evoked potentials: maturational aspects and prognostic value

The aim of this prospective study was to evaluate the diagnostic role of somatosensory evoked potentials (SEP) during the neonatal period with regard to maturational changes and prognostic value in perinatal hypoxic-ischemic encephalopathy. Median nerve SEP analysis was performed in 31 healthy infants (group A1, 33-35 weeks, n = 10; group A2, 36-37 weeks, n = 11; group A3, 38-41 weeks, n = 10) and in 10 term infants with hypoxic-ischemic encephalopathy (group B). Cortical latency N1 and central conduction time values were analyzed for group A in relation to postconceptional age and postnatal age and for group B in relation to degree of hypoxic-ischemic encephalopathy and neurodevelopmental outcome (at the mean age of 6.6 + or - 1.6 years). Central latencies were correlated with postconceptional age but not postnatal age. Mean N1 latency and central conduction time values did not differ significantly between groups A1 and A2; the most pronounced decrease was between groups A2 and A3 (postconceptional ages 36-37 vs 38-41 weeks). In group B, central latencies were prolonged, compared with controls (P < 0.001), but were not significantly correlated with long-term outcome in patients with moderate hypoxic-ischemic encephalopathy (n = 6). Neonatal SEP analysis thus is an objective and noninvasive method for assessing functional integrity of the somatosensory pathway. In term infants, SEPs are a valuable additional tool for early diagnosis of hypoxic-ischemic encephalopathy, but are not prognostic of neurodevelopmental long-term outcome in moderate hypoxic-ischemic encephalopathy.

Neonatal neurobehavior predicts medical and behavioral outcome

OBJECTIVE

This study examined the NICU Network Neurobehavioral Scale (NNNS) as a predictor of negative medical and behavioral findings at 1 month to 4.5 years of age.

METHODS

The sample included 1248 mother-infant dyads (42% born at <37 weeks' gestational age [GA]) who were participating in a longitudinal study of the effects of prenatal substance exposure on child development. Mothers were recruited at 4 urban university-based centers and were mostly black and on public assistance. At 1 month of age, infants were tested with the NNNS. Latent profile analysis was conducted on NNNS summary scales to identify discrete behavioral profiles. The validity of the NNNS was examined by using logistic regression to predict prenatal drug exposure and medical and developmental outcomes through 4.5 years of age including adjustment for GA and socioeconomic status.

RESULTS

Five discrete behavioral profiles were reliably identified; the most extreme negative profile was found in 5.8% of the infants. The profiles showed statistically significant associations with prenatal drug exposure; GA and birth weight; head ultrasound; neurologic and brain disease findings; and abnormal scores on measures of behavior problems, school readiness, and IQ through 4.5 years of age.

CONCLUSIONS

The NNNS may be useful to identify infant behavioral needs to be targeted in well-infant pediatric care, as well as for referrals to community-based early intervention services.

Concurrent validity of the Neurobehavioural Assessment for Pre-term Infants (NAPI) at term age

BACKGROUND

Accurate measurement of neonatal neurological integrity is critical for early identification of pre-term and full-term infants at-risk for developmental disability. The Neurobehavioural Assessment for Pre-term Infants (NAPI) was developed to measure the progression of neurobehavioural development in pre-term infants born between 32 weeks post-conceptional age (PCA) and term. This instrument has many unique advantages; however, criterion validity is unknown and results are subsequently difficult to interpret.

OBJECTIVES

This study examined the concurrent validity of the NAPI against a criterion instrument, the Einstein Neonatal Neurobehavioural Assessment Scale (ENNAS), which measures similar constructs and has demonstrated excellent reliability and validity.

METHODS

A sample of 41 pre-term and full-term infants (40 +/- 2 weeks) was assessed with the NAPI and ENNAS on the same day.

RESULTS

The findings demonstrated that correlations between similar NAPI clusters and ENNAS clusters ranged from 0.35-0.65 and correlations between many similar individual NAPI and ENNAS items ranged from 0.40-0.60. Two NAPI clusters also discriminated between normal, abnormal and suspect performance on the ENNAS.

CONCLUSION

The NAPI has many unique advantages as a tool. It examines neonates serially, has established weekly normative data and requires minimal infant handling. This study provides new validation of the NAPI instrument.

Development and validation of a test battery to assess subtle neurodevelopmental differences in children

There is increasing concern over the impact of low-dose exposures to environmental chemicals on children's neurobehavioral function. To determine subtle alterations in children's function, it is necessary to move beyond global measures such as IQ and employ tests that can detect small, subtle neurodevelopmental effects across a broad array of behavioral domains. We investigated the sensitivity and specificity of a battery of 63 neurodevelopmental tests or tasks designed to detect outcomes representing the type of subtle neurodevelopmental deficits caused by exposure to neurotoxicants in school-aged children. We studied Neonatal Intensive Care Unit (NICU) graduates, a population known to be at risk for both major and mild anomalies in perception, motor functioning, learning, memory and cognition. This population served as a surrogate to evaluate the capacity of these tests and tasks to predict such deficits. The subjects' histories of previous exposures to any environmental neurotoxicants was not ascertainable, but exposures to elevated levels was not suspected. Over one-third of the 63 measures proved capable of detecting pre-diagnosed lower IQ, the presence of a learning disability (LD) or a neonatal risk profile with at least 70% sensitivity and specificity. Some tests were differentially sensitive and specific, depending upon the presence or absence of one or more of several covariates such as gender, age, hearing status, or familiarity with computers. Tests were also eliminated from the battery if they were affected by too many covariates. We propose calling the final battery of tests that are specific and sensitive to subtle neurodevelopmental changes the Rochester test battery (RTB). Further studies are needed to confirm the capability of the RTB to detect subtle changes associated with neurotoxic exposures.

A comparison of developmental assessments of the newborn and young infant

Neonatal neurobehavioral assessments describe a newborn's spontaneous behavioural repertoire and observable responses to environmental stimuli. Infant developmental assessments document the range of developmental skills that emerge and develop over the first years of life. This review highlights two neonatal assessments (Einstein Neonatal Neurobehavioral Assessment Scale, Neurobehavioral Assessment of the Preterm Infant) and two infant assessments (Alberta Infant Motor Scale, Test of Infant Motor Performance). A general description of these tests is followed by their content and psychometric properties. These standardized tests of neurologic integrity are useful in characterizing current developmental status and in monitoring change in performance over time.

Neonatal brain injury

Complacency about long-term outcomes in newborns is being eroded rapidly with new information. We have examined developments in the area from an explicitly clinical approach, focusing on etiology, diagnostic modalities, and therapies. We attempt to discuss relevance from the preterm and the term perspective. Emerging evidence implicating chorioamnionitis as a significant contributor to neonatal brain injury is discussed. Therapeutic modalities such as magnetic resonance imaging and electrophysiological monitoring offer some potentially new tools for the clinician. An exploding series of basic advances suggest several potentially new strands of therapy. We discuss two that deserve further clinical exploration, namely anti-inflammatory strategies and thread hormone supplementation. In the arena of therapy, however, the paucity of large trials from which to guide therapies is a predominant theme, leaving a large reservoir of uncertainty for the clinician.