Abstract
Neurodevelopmental follow-up is a critical component of the evaluation of the neurological development and ongoing clinical needs of the high-risk newborn. Such follow-up is important because it has become increasingly clear that a substantial number of infants who exhibit neurological abnormalities in the newborn period will experience later neurological and developmental difficulties that are likely to seriously limit their educational, social, and other life course opportunities. Unfortunately, in the neonatal period, it is not always possible to accurately predict which infants will experience later neurodevelopmental problems and which will not. This chapter reviews key concepts underlying child development and the processes that influence child neurodevelopmental outcomes. It then outlines the appropriate considerations for the evaluation of a child’s development across the domains of motor, language, cognition, and behavioral outcomes by age.
Keywords
neurodevelopment, follow-up, outcome, cognition, behavior, mental health, language, motor, disability
Neurodevelopmental follow-up is a critical component of the evaluation of the neurological development and ongoing clinical needs of the high-risk newborn. Such follow-up is important because it has become increasingly clear that a substantial number of infants who exhibit neurological abnormalities or who have other serious conditions in the newborn period will experience later neurological and developmental difficulties that are likely to seriously limit their educational, social, and other life course opportunities. Unfortunately in the neonatal period it is not always possible to accurately predict which infants will experience later neurodevelopmental problems and which will not. Furthermore, children’s skills and abilities develop with age and experience, with simpler skills often forming the foundation for the learning of more complex skills. Thus it is often not until a child fails, or is slower to develop a specific skill compared with other children of his or her age, that his or her problem/s become fully apparent. The developmental timing of this will also depend on the function of interest, with neuromotor deficits tending to emerge in the first year of life, while cognitive and behavioral impairment(s) develop more slowly from early childhood to adolescence. Thus it is now widely accepted that high-risk infants require close monitoring and developmental surveillance as part of our ongoing responsibility for care and optimization of their outcomes beyond merely survival and discharge from the neonatal intensive care unit (NICU).
Neurodevelopmental follow-up is also important for family support, as well as from a neonatal and public health perspective. First, families want to know if their child is healthy and growing normally, or if problems are likely to be encountered in the future. Such information is valuable for both stress management and family decision-making. It also enables families to proactively plan and advocate for their child’s needs. This can be especially relevant at key transition points in a child’s life when additional challenges may be encountered by a child, such as starting child care or changing schools. During these times, families are also likely to benefit from extra advice and support.
Second, information about high-risk children’s outcomes is crucial for the improvement of existing neonatal services. Specifically, possible positive and negative effects of different medical interventions on neurological and developmental outcomes may not be apparent in the first years of life. Therefore neurodevelopmental follow-up data can provide valuable feedback information about the efficacy and potential risks associated with different clinical care approaches beyond survival and short-term health outcomes. Relatedly, this kind of information can also be extremely useful both for counseling families in the NICU and providing guidance to follow-up and early intervention service providers about the nature of adverse outcomes and when such outcomes may become visible during a child’s development.
Finally, from a broader public health perspective, careful follow-up screening on a regular basis helps ensure that child problems are detected early. This is important because targeted interventions can be effective in treating and preventing significant neurodevelopmental problems, which if left untreated may worsen and/or place the child at increased risk of more complex impairments. Thus early screening and intervention serves to not only minimize child and family distress, but also to reduce the burden of long-term care on public health, social, and educational services over the child’s life span.
Principles and Concepts of Child Development
To accurately identify deviations and delays in a child’s development, it is essential to have an appreciation of the normative developmental timing of different skills and abilities, and even more importantly, the processes that shape child development. Thus some key principles and concepts of child development are briefly reviewed.
Life Course Development
Child development by definition is recognized to be dynamic over time and child age , with both quantitative and qualitative changes in functioning observed from birth to old age. Therefore it is now more common to talk about life course development or pathways of development in recognition of the fact that early life experiences can affect an individual’s development over his or her life course. Specifically, early perinatal experiences have the potential to both positively or negatively alter an individual’s life course trajectory. However, in addition, a child’s experiences in his or her family, at school, and in his or her community will also mold his or her behavior in unique ways. Thus there is often considerable inter- and intraindividual variability in observed outcomes for both typically developing and high-risk children. This poses additional challenges for the assessment of delay or impairment in children subject to early neonatal risk, especially at younger ages when this variability is particularly pronounced in the timing of key developmental milestones (e.g., walking and talking). As a result, accurate pediatric diagnosis and prognosis prediction is uniquely challenging because of dynamic changes in children’s development with age ( Fig. 11.1 ).
For this reason, repeated assessments and the collection of information from multiple sources are advised. Longer-term follow-up is also recommended when possible because this will ensure that children are monitored until adaptive functioning in early developing skills, such as emotional and behavioral regulation, is achieved. It also allows for the opportunity to reliably and validly assess more complex abilities that do not come online developmentally until school age and later, but are nonetheless very important for learning and daily life functioning. These include, for example, higher-level cognitive skills such as planning and organization of action, as well as many mental health disorders. Fig. 11.2 provides a broad overview of the approximate developmental progression of functional skills across multiple domains of child development.
Domains of Development
When thinking about child development within this framework, it can be helpful to conceptualize a child’s neurodevelopmental functioning as spanning several domains, which include (1) physical health/growth, (2) neuromotor function, (3) language development, (4) cognition and learning, (5) emotional and behavioral well-being or mental health, and (6) social functioning. Although representing somewhat independent skill sets, it is important to note that these domains are also interrelated because functioning in one domain can have an adverse effect on developmental opportunities and functioning in another. Relatedly, early skills acquired during infancy and early childhood form vital building blocks for later competencies not only within the same domain but also across domains. For example, a child with delayed language development may be more prone to develop regulatory and behavior problems because of his or her difficulties in communicating his or her needs to others. Similarly, a child with cerebral palsy (CP) who is unable to participate fully in sport at school may have fewer opportunities to interact and develop friendships with his or her peers, which in turn will limit his or her social learning experiences and long-term social development. These cascading challenges can have adverse cumulative impacts on a child’s functioning over time, which is sometimes referred to as the Matthew effect.
Importance of a Child’s Postnatal Experiences
Previously a child’s functional abilities were viewed as an expression of his or her genetic inheritance and associated brain structural maturational processes. However, a large body of human infant and experimental research now shows that brain development and resulting child functional outcomes are the result of complex interactions between biological and environmental influences. Specifically, while an individual’s genes provide essential information for establishing basic patterns of neuronal growth and connectivity, it is the interaction of genes and the experiences children have early in life (and the environment in which they have them) that not only shape their developing brain architecture but also how genes are turned on and off, and the way they are expressed (epigenetics). Healthy brain development is optimized when a child is raised in a nurturing environment that is characterized by (1) human interactions that are responsive, emotionally supportive, and developmentally stimulating; (2) adequate nutrition and child health support; (3) protection from threats; and (4) where early learning opportunities are fostered. For the young child, his or her experiences of the world are largely defined by his or her home environment and interactions with parents and other family members. However, unfortunately, not all children experience optimal or even good enough home environments, but rather are exposed to varying degrees of environmental risk, ranging from poverty, social adversity, poor parental mental health, parenting problems, family dysfunction, and neighborhood/community stress or violence. Evidence shows that these adverse experiences, which often co-occur, adversely affect brain development, and, in turn, a child’s physical, cognitive, and social development. Often these effects are additive or even interactive, with children exposed to higher levels of family social and economic adversity being at greater risk of neurodevelopmental delay or impairment. Indeed, there is also some suggestion that developmentally vulnerable children may be more sensitive to experiential effects than typically developing children, gaining greater benefit from a nurturing rearing environment and potentially being more severely affected by exposure to an adverse rearing environment. The notion that the brain continues to adapt and change in response to experiences throughout childhood and into adulthood is sometimes referred to as neural plasticity .
Related to the importance of a child’s experiences for brain and behavioral development, it is important to note that the child is not simply a passive recipient of environmental influence, but rather is an active participant in his or her world. This concept was first introduced by Sameroff and Chandler, who argued that the relationship between a child and his or her environment was a transactional one. From this perspective, a child’s behavior and neurodevelopmental outcome is the consequence of dynamic, transactional interactions between genetic, constitutional, neurobiological, biochemical, psychological, and sociological processes. For example, a child who is temperamentally difficult, or is more demanding to care for developmentally, can increase risks of maternal stress/depression as well as marital discord. These parental and family challenges can in turn impede the family’s ability to parent and manage difficult child behavior, further exacerbating problems. As highlighted in this example, an implication of the transactional model is not only that environmental factors are important in shaping child outcomes, but also that the child’s reciprocal characteristics partially determine the nature of his or her own environment.
Which Infants Need Follow-Up?
A child may require specialized neurodevelopmental follow-up for reasons specific to the child and/or his or her family. Table 11.1 provides a list of neonatal medical conditions for which follow-up is recommended based on a more recent multidisciplinary consortium of specialists from Australasia and the United Kingdom. See also those made by the American Academy of Pediatrics [AAP] in 2004. Also listed in Table 11.1 are family factors that may themselves justify child developmental surveillance, but certainly when combined with a clear medical indication reinforce the need for referral because later neurodevelopmental risk is likely to increase as the number of comorbid conditions or risk factors increase. For example, a growth curve analysis of the cognitive trajectories of very preterm (VPT)– and full-term–born children between the ages of 4 and 12 years found that early cerebral white matter abnormalities (WMA) and family social risk contributed additively to children’s later cognitive outcome. Cerebral WMA were assessed based on qualitative magnetic resonance imaging (MRI), and social risk consisted of a composite measure of five factors including early motherhood (<21 years), maternal educational underachievement (did not graduate from high school), minority ethnicity, low socioeconomic status (SES), and single parent family. As illustrated in Fig. 11.3 , VPT children without moderate to severe WMA on neonatal MRI and no family social risk fared the best, with the highest average cognitive trajectory. The second highest functioning group were those children born VPT who had no observable WMA on term MRI but were raised in family circumstances characterized by high social risk (≥2 social risk factors). These children obtained later IQ scores that were, on average, 4.7 points lower than the lowest risk group, indicating the cognitive risk associated with raising a VPT born child in a socioeconomically disadvantaged family environment. The third best functioning group consisted of those VPT children subject to WMA on neonatal MRI but who were raised in a family environment unaffected by social and economic adversity. These children obtained IQ scores that were on average 7.4 IQ points lower than the lowest risk preterm group. In contrast, when VPT born children were subject to both risk factors (i.e., moderate to severe WMAs and high social risk), the adverse effects on cognitive function were increased, with the average cognitive trajectory for these VPT born children found to be 12 IQ points below that of low-risk (no WMA, low family social risk) VPT born children. These findings demonstrate that the presence of both biological and family social risk have an additive impact on later cognitive function and life course opportunities for children born VPT. They also highlight that it is critically important that every effort be made to ensure that infants being raised in higher social risk families are not lost to follow-up because these children are probably the group that most needs monitoring and support.
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Models of Neurodevelopmental Follow-Up
Neurodevelopmental follow-up can take several forms depending on the population of concern, the resources available, and the purpose of the visit. The first model consists primarily of s urveillance and monitoring , which involves observing a child’s development and tracking parent concerns over time and across multiple domains of development. Standardized developmental screening measures are typically used to proactively identify children who may have a developmental problem or show early delay in one or more areas of development (e.g., language), which if untreated will place them at increased risk of significant developmental problems in the future. Within this neurodevelopmental screening model, information should also be gathered about possible risk and protective factors in the child’s environment that may be assisting or hindering their development, to help inform referral decisions and intervention planning.
A second alternative model or approach consists of in-depth developmental assessment of the child in multiple or specific domains. This may occur at targeted ages to supplement data from routine screening evaluations and is probably most relevant for the highest risk populations of infants. The goal of this approach is to specify the precise nature of the child’s developmental problem/s, whether they need intervention, and if so, what approaches would be best.
A third less common approach is a hybrid of the surveillance and assessment models. This approach, which tends to be more common in publicly funded health care systems, seeks to conserve limited resources by providing minimal screening surveillance for all or most at-risk children, with intensive (and expensive) assessment resources limited to those children who fail predetermined screening criteria. Specifically, all children referred for evaluation are monitored regularly using child screening and parent interview measures, with children referred for in-house intensive assessment and ideally treatment on an individual basis. When difficulties resolve, the child would typically be transferred back into the surveillance track where he or she would continue to be monitored.
The Timing of Follow-Up Assessments
For high-risk newborn infants, follow-up assessments should be more frequent immediately after discharge, but then become gradually more widely spaced with increasing child age. The goal is to be sure that all expected developmental stages are achieved in the expected time window. The exception to this would be when additional visits were indicated because of the presence of a specific neurodevelopmental problem at the time of discharge from the NICU (e.g., feeding, poor growth), or if new neurodevelopmental problems were detected at a previous follow-up visit. Table 11.2 provides a list of suggested ages based on current recommended standards and relevant child outcomes and family factors to assess. In general, newborns at risk for neurodevelopmental delay should be assessed regularly for early rapid development in the first 2 years (toddlerhood and infancy) at intervals of not more than 6 months apart. After the age of 2 or 3 years, if the child is progressing well, these assessments could be done annually at school entry, with biannual follow-up through middle childhood to test for attention and executive functioning problems, school achievement, and socioemotional adjustment/mental health.
For the child born very or extremely preterm, it is important to note that these ages should be adjusted for the degree of prematurity, especially in a research setting, because data show that without age correction, these children will be unduly disadvantaged on cognitive test measures. This bias is most marked during early childhood but does persist to a lesser degree into school age. In the clinical setting, the overidentification of cognitive delay among children at neurodevelopmental risk may be less of a problem because it may help children access much-needed services. However, for research purposes, when the objective is to assess the extent of a problem and ensure comparability across studies, not correcting for gestational age at birth can be problematic and needs to be a consideration.
Duration of Follow-Up
There are usually mandated limits to publicly funded or subsidized neurodevelopmental follow-up, with some programs commonly only receiving health services funding to the age of 3 years, although in some countries this has been extended into the early school years. Data certainly suggest that follow-up until school entry is warranted for several reasons. First, infant and early childhood developmental measures are poor to modest predictors of long-term child outcomes, particularly for cognitive scores. Second, some developmental disorders cannot be reliably and accurately assessed at a young age, such as executive function impairments, specific learning problems (e.g., dyscalculia, dyslexia), and common mental health disorders such as attention-deficit/hyperactivity disorder (ADHD) and anxiety disorders. Third, there is growing evidence that a school readiness evaluation can proactively identify children who are at high risk of educational underachievement prior to school entry, assisting in effective utility of limited special needs resources.
Neurodevelopmental Domains to Assess
The specific neurodevelopmental outcomes assessed will vary with the child’s age and developmental level, but effort should be made to ensure that all the neurodevelopmental domains outlined previously are monitored in some way with age-appropriate tools. Also, as noted previously, different abilities will have particular functional importance at different ages. Therefore, child and family outcome measures are likely to be influenced by child and family needs/issues at the time of the assessment, or in the near future (e.g., as mothers transition back to work or children transition from kindergarten to school).
The primary focus of the following discussion is to outline relevant areas for assessment from both the child’s and the family’s perspective, and to indicate how these might vary in importance, depending on the age of the child being seen. Some measurement suggestions are given, but providing detailed advice about specific measures is beyond the scope of this chapter. Where possible we refer the reader to recent reviews in which more detailed information can be found about specific standardized tools, the constructs they measure, child ages for which they are suitable, and a description of their relative psychometric properties.
While assessment with standardized measures will be a central part of the evaluation, we would also echo the advice given in Chapter 9 about the value of direct observation of the child, and also potentially the child’s interactions with family members. This can be done informally, or could involve the use of validated global behavior rating scales to provide supplementary information about focused attention, behavioral regulation, joint attention, affect, and so forth. Direct observations should ideally be completed in an independent manner by individual staff interacting with or observing the child in different situations (i.e., during testing or even in the waiting room). These can then be later discussed as a team, with consensus ratings or clinical evaluations made. Attaching an actometer to the child’s ankle may also be helpful if ADHD is suspected.
More generally, several other good practice considerations are worth noting before a detailed discussion of neurodevelopmental domains to monitor and/or assess. These are as follows.
Staff Training
The personnel involved will likely vary depending on the number of domain areas to be assessed. However, when assessing children with conditions where multiple functional problems are anticipated, follow-up assessments should involve a multidisciplinary team of health professionals. If straightforward screening measures such as parent report measures are being used, it is often possible for these to be administered by appropriately trained and supervised support staff. But all staff responsible for administering and interpreting specific measures ought to be appropriately qualified and trained to do so. Also, when multiple staff administer the same tool (e.g., Bayley Scales), intertester reliability should be regularly monitored to ensure measurement consistency and avoid problems with tester drift.
Family and Cultural Considerations
Research shows that family engagement is associated with positive outcomes for children. In addition, families can provide a perspective on their child that is not readily accessible to the assessment team. They are also the individuals in the child’s life that are best placed, and most motivated, to enhance their child’s learning experiences and to advocate for their child’s needs. As a result, there has been a shift toward the adoption of family-centered care practices worldwide. Key tenets of the family-centered care model include (1) establishing an emotionally and culturally safe/supportive care environment; (2) treating families as equal and collaborative partners in all aspects of the follow-up evaluation; (3) providing respectful, compassionate care that is individualized to the child and his or her family; and (4) being culturally and socially responsive to the family’s needs and values. Strategies for engaging and communicating effectively with families are listed in Table 11.3 . Existing staff may require training in these family-centered and culturally sensitive practices.
Choice of Assessment Setting
A major challenge of many follow-up programs is nonattendance and/or high attrition or drop-out over time. The listed family engagement strategies may help reduce this ( Table 11.3 ). However, one of the most concerning aspects of poor attendance is that children from socioeconomically disadvantaged family backgrounds tend to be overrepresented among the “no show” group. Yet, as indicated earlier, there are clear data demonstrating that these children tend to be at greatest developmental risk and therefore most in need of intervention services. To address this problem, some services may choose to offer home visits as an alternative or adjunct to their center-based program. In our experience, even a single home visit during the initial stages of follow-up can help establish a relationship with the family and increase long-term family follow-up compliance. Preliminary data also support this.
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Deciding Which Measure to Use
While the choice of measures used for different purposes may vary depending on personnel and regional preferences, several factors should be considered. Measures should have strong psychometric properties, including construct validity and test-retest reliability, as well as inter- and intratester reliability. Preference should also be given to well-standardized measures. That is, they should have good norms that are relevant to the local population. To minimize assessment time, abbreviated measures are sometimes appropriate.
Minimizing Measurement Bias
A final issue to be mindful of is to ensure that measurement bias is minimized. This includes two key forms of bias—tester bias and report source bias. Tester bias results from the evaluator not being blind to the infant’s/child’s clinical record creating the opportunity for pretesting perceptions of the child’s performance to be altered. For example, awareness that the child has severe brain injury on neuroimaging may inadvertently influence a tester’s expectations of test performance and possibly their behavior toward the child during testing and scoring, that the child will be a poor performer. This bias is particularly important to eliminate in any research evaluations where the tester should always be blinded to the clinical information of the subject being evaluated.
The second form of bias is that of report source bias. Report source bias occurs when information is obtained from a single informant. This is most relevant for reports of child behavior and is applicable to both the clinical and research setting. Reliance on a single report source such as the primary caregiver can be problematic when his or her perceptions of the child are potentially colored by his or her own mental health difficulties (e.g., depression, anxiety), personal situation, past experiences (in the NICU or with another child), or possibly the quality of his or her own relationship with the child. For example, parents of preterm survivors have been found to report much higher rates of attentional problems than teachers, which may in part reflect either their child’s behavior and/or their own understandable, but heightened, anxieties about these possible outcomes based on their earlier NICU experience. Thus, ideally when problems are suspected, it is advisable to obtain the perspectives of multiple significant adults in the child’s life.
In line with the developmental framework outlined previously, functional neurodevelopmental domains that should form part of a comprehensive follow-up program include (1) physical health/growth , (2) neuromotor function , (3) language development , (4) cognition and learning , (5) emotional and behavioral well-being or mental health , and (6) social functioning . While all domains are discussed, emphasis is placed on those domains most pertinent to neonatal and neurology follow-up. In addition to child neurodevelopmental domains, relevant family characteristics are also addressed. The overall goal is to highlight relevant child and family variables to assess, and how these may change in importance with the age of the child. How comprehensive the follow-up is in terms of the number of domains assessed and depth of measurement will likely vary at each time point depending on the purpose, resources, and time available. The following resources may also be helpful.
Child Characteristics
Physical Health/Growth
This domain includes a number of different areas of potential health concern.
Neurological
A thorough neurological examination, including evaluation of the head, cranial nerves, motor, and sensory system should be completed by a physician who is trained in the neurological examination of the infant and child. This would usually be the pediatrician or child neurologist. The most frequent abnormalities that are found in high-risk infants and children relate to tone, power, and coordination.
Vision and Hearing
Major visual and hearing problems are often diagnosed before discharge home. Hearing screening is often universal for most babies before discharge. Eye examinations are also typically routine for high-risk groups, such as those infants born VPT or less than 1500 g in birth weight. Other high-risk groups who may not have had such assessments before discharge might need specialized follow-up by ophthalmologists or audiologists. Therefore general hearing tests and basic visuomotor assessments should be performed routinely as part of neurodevelopmental follow-up during the first 2 years of life. Infants identified to have abnormal visual (i.e., strabismus ) or hearing function ( failed hearing screen ) should be referred for assessment. In later childhood, more subtle optical problems such as refractive errors and visual processing disorders occur more frequently in high-risk groups, and these problems can interfere with learning. Similarly, hearing disorders other than deafness, such as short-term auditory memory problems or figure-ground perceptual problems (difficulty hearing in a noisy background), are common among high-risk infants and can also interfere with learning.
Growth
Assessment of height, weight, and head circumference is relevant at all ages, but especially in early life when growth rates are high, and poor growth can be readily detected with growth charts for child age and sex. This is important because poor growth is common in high-risk infants and may be an indicator of underlying health problems. Better postdischarge linear growth is also associated with better neurodevelopmental outcomes. The WHO Child Growth Standards are available at http://www.who.int.easyaccess2.lib.cuhk.edu.hk/childgrowth/standards/en/index.htm . Specific growth charts also exist for some specific populations, such as children with Down syndrome and Turner syndrome. There are also equations available for estimating total height from knee height, which can be helpful if a child is unable to stand up straight for measurement (e.g., children with CP). In general, growth patterns are more important than single growth measurements in monitoring a child’s health and development. Poor growth is common in VPT infants in the NICU, with human milk–fed infants often more affected. For these children, continued supplementation of energy, protein, and minerals is recommended. Human milk–fed infants may also benefit from partial milk fortification. While many of these infants will catch up in their growth by late infancy, a number will continue to have difficulties through late adolescence, with a minority never catching up. An additional complication for some children as their growth slows with age is overweight and obesity. This is likely to be of greatest concern in developed countries where obesity is a public health problem.
Feeding Problems
Children with neurological problems are at increased risk of feeding problems, and therefore may require prolonged tube feeding after discharge. This can lead to heightened oral sensitivity and delays in adaptive feeding skills that may impede the development of healthy eating skills and physical growth. These difficulties are also highly stressful for families and can create interactional difficulties at mealtimes and more generally. Thus evaluation and support of these problems can require specialized speech pathology therapists with additional radiological evaluations.
Daily Functioning
Skills in daily living, also known as adaptive skills, such as with feeding, dressing, toileting, communication, mobility, socialization, and emotional regulation, appropriate for the age of the child, are all important to consider.
Brain Development.
The clinical utility of including an MRI as part of a neurodevelopmental follow-up is highly dependent on the expertise of the person reporting and interpreting the MRI. In particular, in the neonatal period, given the inverted contrasts of white and gray matter compared with adult brain MRI, interpretation can be challenging for the inexperienced reader. However, despite these challenges there have been several features of a neonatal MRI at term that have reasonably good predictive value for later neurodevelopmental outcome, and therefore may be worth considering as part of follow-up. For the preterm-born infant , the presence of T1 and T2 characteristics of myelin in the internal capsule and/or asymmetry with absence of myelin on term MRI can be a predictor of high risk of hemiplegia CP in the context of focal cerebral white matter (WM) lesions. Isolated diffuse hyperintense signal on T2-weighted neonatal images, although indicative of a higher water content in these areas and potentially a sign of injury, has in subsequent studies not been able to reliably predict neurodevelopmental outcome. Presence of signs of moderate to severe WM injury on term equivalent MRI have also been linked with an increased risk of motor and, to a lesser extent, cognitive impairment assessed with the Bayley Scales in infancy and early childhood. In later childhood, these children continued to have neurocognitive impairments across multiple cognitive functions, including executive functions. In contrast, VPT children without WM abnormalities on term MRI had generally similar motor and cognitive outcomes as their same-age, full-term peers. These data suggest that a term equivalent MRI with clinical scoring of the conventional T1- and T2-weighted MRI newborns may assist in the identification of infants who are at increased risk of neurodevelopmental problems. Combining MRI at term equivalent with a neurological exam and serial cerebral US data further improves predictability for later neurodevelopmental problems. In addition, it will be important to also take other aspects of the child’s life into account because a child’s developmental progress over the course of childhood will also likely depend on a multitude of contextual factors. Therefore a normal MRI should not be grounds to exclude a child from neurodevelopmental follow-up. Finally, for the preterm child, adding brain biometrics such as biparietal diameter, transcerebellar width, and ventricular size may further improve predictability.
For the term-born infant with HIE , brain lesions detected on MRI with and without hypothermia have been shown to have good predictive value for neurodevelopmental outcome. For example, the absence of impairment in the signal in the posterior limb of the internal capsule has also been shown to be a powerful predictor of motor disability in the term-born infant with encephalopathy.
Finally, in recent years, the development of image-based analysis with a mathematical and informatics-based approach has been impressive, and these techniques have allowed us to study in more detail the brain structure-function relationships relevant for predicting neurodevelopmental outcomes in high-risk newborns. These techniques include brain volumetry, diffusion weighted imaging, and functional network connectivity analysis.
Neuromotor Function
CP and delayed motor development are more prevalent in high-risk populations of children compared with the general population, so repeated neurological assessment is important in the early years. CP represents an umbrella term for conditions that are characterized by a nonprogressive, but not unchanging, motor impairment related to brain disturbances that have occurred early in development. Between 1% and 3% of all live-born infants are affected by CP, with this rate increasing to 8% to 40% among high-risk infants, such as those born extremely preterm. It is typical for the severe forms of CP to present earlier in childhood, usually within the first year after birth, with disordered tone and tendon reflexes, along with abnormal motor development. These are categorized into (1) spastic—which can be mono-, di-, or quadriplegic; (2) dystonic; and (3) choreoathetoid forms. Milder CP, however, may not be able to be diagnosed conclusively until later ages, sometimes even after the child has started to walk. Any degree of CP should be graded according to the Gross Motor Function Classification System (GMFCS). A recent systematic review describes the prevalence, type, and distribution of CP according to gestational age. Several reviews have also examined the utility of different tools in predicting CP. Findings suggest that assessment of general body movements in the first months of life and MRI at term equivalent can be predictive of CP in high-risk infants.
Apart from CP, many high-risk children have delayed motor development during infancy. Therefore monitoring motor milestones is important. Although some children with initial motor delay will catch up, others will have ongoing problems with motor function and coordination. Yet others may be later diagnosed with developmental co-ordination disorder (DCD). Formal evaluation of milder motor dysfunction is typically done by a physical therapist or an occupational therapist. The pooled prevalence of motor impairment in high-risk preterm children without CP is 19% for moderate impairment and 40% for mild-moderate impairment.
Table 11.4 provides a list of motor scales commonly used in the assessment of infants and children. Several of these infant measures are reviewed by Spittle and colleagues, including Prechtl’s General Movements Assessments (birth to 20 weeks, corrected for prematurity), the Test of Infant Motor Performance (TIMP, 34 weeks to 4 months corrected age), Alberta Infant Motor Scale (AIMS, 0 to 18 months), the Neuro-Sensory Motor Development Assessment (NSMDA, 1 month to 6 years), and the motor subscale of the Bayley Scales of Infant and Toddler Development (BTSID, 1 to 42 months). General movements and the TIMP are most useful in the first few months of life, with the AIMS, NSMDA, and Bayley being better from around 4 months upward. In older children, the Movement Assessment Battery for Children (MABC, 3 to 16 years) tends to be the most widely used motor assessment tool, assessing both fine and gross motor abilities.
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