Population case-control study of cerebral palsy: neonatal predictors for low-risk term singletons

Neonatal well-being and timing of brain injury in persons with cerebral palsy born at term or late preterm

AIM

To describe the distribution of neuroimaging patterns in a term/late preterm population-based cohort with cerebral palsy (CP), ascertain associations between neuroimaging patterns and neonatal well-being, estimate the proportion with antenatal or perinatal timing of neuropathology, and apply this information to the understanding of common mechanisms of brain injury and causal pathways.

METHOD

The cohort for this observational study comprised 1348 persons born between 1999 and 2017 in Victoria, Australia. Using algorithms designed for the study, neonatal well-being and timing of brain injury were tabulated for the whole cohort and across neuroimaging patterns and birth epochs.

RESULTS

Clinical and demographic profiles, neonatal well-being, and timing of brain injury differed across neuroimaging patterns. An estimated 57% of the cohort had a complicated neonatal period. Timing of brain injury was antenatal in 57% and perinatal in 41%. A decrease in the relative proportions of perinatal timing of brain injury was observed over a period when the rates of CP in live births at term decreased.

INTERPRETATION

This study begins to bridge the knowledge gap about causation in CP, moving towards better description of the main mechanisms of brain injury and their contribution within CP cohorts, and facilitating the ability to monitor changes over time and the success of preventive measures.

WHAT THIS PAPER ADDS

In a population-based, term/late preterm cohort with cerebral palsy, 57% had a complicated neonatal period. In the same cohort, 57% had presumed antenatal timing of brain injury. The relative proportion with perinatal injury decreased over time.

Protocol for a randomized controlled trial to evaluate a year-long (NICU-to-home) evidence-based, high dose physical therapy intervention in infants at risk of neuromotor delay

INTRODUCTION

Developmental disabilities and neuromotor delay adversely affect long-term neuromuscular function and quality of life. Current evidence suggests that early therapeutic intervention reduces the severity of motor delay by harnessing neuroplastic potential during infancy. To date, most early therapeutic intervention trials are of limited duration and do not begin soon after birth and thus do not take full advantage of early neuroplasticity. The Corbett Ryan-Northwestern-Shirley Ryan AbilityLab-Lurie Children's Infant Early Detection, Intervention and Prevention Project (Project Corbett Ryan) is a multi-site longitudinal randomized controlled trial to evaluate the efficacy of an evidence-based physical therapy intervention initiated in the neonatal intensive care unit (NICU) and continuing to 12 months of age (corrected when applicable). The study integrates five key principles: active learning, environmental enrichment, caregiver engagement, a strengths-based approach, and high dosage (ClinicalTrials.gov identifier NCT05568264).

METHODS

We will recruit 192 infants at risk for neuromotor delay who were admitted to the NICU. Infants will be randomized to either a standard-of-care group or an intervention group; infants in both groups will have access to standard-of-care services. The intervention is initiated in the NICU and continues in the infant's home until 12 months of age. Participants will receive twice-weekly physical therapy sessions and caregiver-guided daily activities, assigned by the therapist, targeting collaboratively identified goals. We will use various standardized clinical assessments (General Movement Assessment; Bayley Scales of Infant and Toddler Development, 4th Edition (Bayley-4); Test of Infant Motor Performance; Pediatric Quality of Life Inventory Family Impact Module; Alberta Infant Motor Scale; Neurological, Sensory, Motor, Developmental Assessment; Hammersmith Infant Neurological Examination) as well as novel technology-based tools (wearable sensors, video-based pose estimation) to evaluate neuromotor status and development throughout the course of the study. The primary outcome is the Bayley-4 motor score at 12 months; we will compare scores in infants receiving the intervention vs. standard-of-care therapy.

Epidemiology of Cerebral Palsy among Children and Adolescents in Arabic-Speaking Countries: A Systematic Review and Meta-Analysis

Background: Studies on cerebral palsy among children and adolescents in Arabic-speaking countries are scarce. In this systematic review, we aimed to describe the epidemiology of cerebral palsy among children and adolescents in Arabic-speaking countries in terms of prevalence, risk factors, motor types, and rehabilitation. Methods: Six key bibliographic databases were searched for relevant literature published to 17 July 2021. Titles and abstracts were screened for potential inclusion and two independent reviewers screened the full texts of potential articles following pre-defined inclusion/exclusion criteria. The included studies were evaluated independently by three reviewers. The risk of bias was assessed, and data were extracted and analysed. Results: A total of 32 studies from 7 countries met our inclusion criteria. The prevalence of cerebral palsy in Arabic-speaking countries was 1.8/1000 live births (95% CI: 1.2–2.5). Spastic cerebral palsy was the most common motor type, representing 59.8% (95% CI: 46.2–72.7) of pooled estimates. This included children with spastic quadriplegia, diplegia, and hemiplegia; 25.1% (95% CI: 18.2–32.8), 16.2% (95% CI: 11.4–23.3), and 10.4% (95% CI: 7.3–13.8), respectively. Consanguinity was high and represented 37.7% (95% CI: 29.3–46.6). Only one included study reported the types of rehabilitation received (e.g., physiotherapy and assistance devices). Conclusions: This paper provides a summary of the epidemiology of cerebral palsy in Arabic-speaking countries and highlights areas for future research. There is still a substantial knowledge gap on the epidemiology of cerebral palsy in these regions. Countries in the Arab region should follow examples of countries that have successfully established cerebral palsy registries to generate evidence on epidemiology of cerebral palsy and opportunities for prevention.

Early Clinical Features of Cerebral Palsy in Children Without Perinatal Risk Factors: A Scoping Review

BACKGROUND

The early identification of cerebral palsy (CP) in the primary care context is often problematic and referral for diagnosis often delayed. This study aimed to identify clinical features associated with the early detection of CP that can be used by the primary care provider.

METHODS

We performed a scoping review by searching six electronic databases. We included English language articles that addressed the diagnosis of CP and/or its differential diagnosis in children and ways of detecting CP before the diagnosis is established (i.e., early clinical signs of CP) via (1) questions on the patient's clinical history, (2) developmental screening and/or health questionnaires, or (3) physical or neurological examination.

RESULTS

Included studies (n = 41; 27 overview studies and 14 original studies) were grouped into the three themes. Most of the overview articles relied on expert opinion, and all original studies included patients at high risk of developing CP. The most commonly identified features from each theme were early hand preference on clinical history, delayed or absent achievement of motor developmental milestones on developmental screening, and persistent primitive reflexes on neurological examination.

CONCLUSIONS

Overall, the literature on the early observable clinical signs that should prompt referral for investigation of possible CP in the specific context of well-baby care surveillance was sparse and inconsistent. Further research should focus on evaluating the contribution of readily identifiable clinical features.

Early Diagnosis and Treatment of Cerebral Palsy in Children with a History of Preterm Birth

Infants born preterm are at increased risk of cerebral palsy (CP), with the risk increasing with decreasing gestational age. Although preterm children are at increased risk of CP compared with their term-born peers, most preterm children do not have CP and thus, it is important to have a standardized process for detecting those children at high risk of CP early. A combination of clinical history, neuroimaging, and physical examination is recommended to ensure early, accurate diagnosis. Early detection of CP is essential for timely early intervention to optimize outcomes for children and their families.

Antecedents of cerebral palsy according to severity of motor impairment

INTRODUCTION

The purpose of this study was to determine whether antecedents and neuroimaging patterns vary according to the severity of motor impairment in children with cerebral palsy.

MATERIAL AND METHODS

A population-based study in which all 309 term-born children with spastic and dyskinetic cerebral palsy born between 1983 and 1994 and 618 matched controls were studied. Antecedents were retrieved from obstetric records. Information on neuroimaging was retrieved from the cerebral palsy Register of Western Sweden. Cases were grouped by severity of motor impairment: mild (walks without aids), moderate (walks with aids) or severe (dependent on wheelchair). Binary logistic regression, the Cochran-Armitage test for trends, interaction analyses and interrelationship analyses were performed.

RESULTS

Antecedents associated with mild motor impairment were antepartum (placental weight, maternal weight and antibiotic therapy) or intrapartum and postpartum adverse events (meconium-stained amniotic fluid, low Apgar score, admission to neonatal intensive care unit and neonatal encephalopathy). Antecedents associated with severe motor impairment were antepartum (congenital infection, small head circumference and brain maldevelopment) or intrapartum and postpartum (emergency cesarean section and maternal antibiotic therapy). Comparisons between mild and severe motor impairment revealed congenital infection, maldevelopment, neonatal encephalopathy and meconium aspiration syndrome significantly more often in the group with severe motor impairment (p < 0.05). White matter injury was the most common neuroimaging pattern in mild motor impairment, whereas maldevelopment and cortical/subcortical lesions were most common in the severe motor impairment group.

CONCLUSIONS

Our results suggest a variation in antecedents associated with cerebral palsy, related to severity of motor impairment. Timing of antecedents corresponded to neuroimaging patterns.

Systematic Review of Cerebral Palsy Registries/Surveillance Groups: Relationships between Registry Characteristics and Knowledge Dissemination

The aims of this study were to provide a comprehensive summary of the body of research disseminated by Cerebral Palsy (CP) registries and surveillance programs from January 2009 through May 2014 in order to describe the influence their results have on our overall understanding of CP. Secondly, registries/surveillance programs and the work they produced were evaluated and grouped using standardized definitions and classification systems.

METHOD

A systematic review search in PubMed, CINAH and Embase for original articles published from 1 January 2009 to 20 May 2014 originating from or supported by population based CP registries and surveillance programs or population based national registries including CP were included. Articles were grouped by 2009 World CP Registry Congress aim, registry/surveillance program classification, geographical region, and the International Classification of Function, Disability and Health (ICF) domain. Registry variables were assessed using the ICF-CY classification.

RESULTS

Literature searches returned 177 articles meeting inclusion criteria. The majority (69%) of registry/surveillance program productivity was related to contributions as a Resource for CP Research. Prevention (23%) and Surveillance (22%) articles were other areas of achievement, but fewer articles were published in the areas of Planning (17%) and Raising the Profile of CP (2%). There was a range of registry/surveillance program classifications contributing to this productivity, and representation from multiple areas of the globe, although most of the articles originated in Europe, Australia, and Canada. The domains of the ICF that were primarily covered included body structures and function at the early stages of life. Encouragingly, a variety of CP registry/surveillance program initiatives included additional ICF domains of participation and environmental and personal factors.

INTERPRETATION

CP registries and surveillance programs, including novel non-traditional ones, have significantly contributed to the understanding of how CP affects individuals, families and society. Moving forward, the global CP registry/surveillance program community should continue to strive for uniformity in CP definitions, variables collected and consistency with international initiatives like the ICF so that databases can be consolidated for research use. Adaptation to new technologies can improve access, reduce cost and facilitate information transfer between registrants, researchers and registries/surveillance programs. Finally, increased efforts in documenting variables of individuals with CP into adulthood should be made in order to expand our understanding of CP across the lifespan.

Fetal growth restriction and risk of cerebral palsy in singletons born after at least 35 weeks' gestation

OBJECTIVE

The objective of the study was to improve the understanding of etiological paths to cerebral palsy (CP) that include fetal growth restriction by examining factors associated with growth restriction that modify CP risk.

STUDY DESIGN

In a total population of singletons born at or after 35 weeks, there were 493 children with CP and 508 matched controls for whom appropriateness of fetal growth could be estimated. Fetal growth was considered markedly restricted if birthweight was more than 2 SD below optimal for gender, gestation, maternal height, and parity. We examined maternal blood pressure in pregnancy, smoking, birth asphyxia, and major birth defects recognized by age 6 years as potential modifiers of CP risk in growth-restricted births.

RESULTS

More than 80% of term and late preterm markedly growth-restricted singletons were born following a normotensive pregnancy and were at statistically significantly increased risk of CP (odds ratio, 4.81; 95% confidence interval, 2.7-8.5), whereas growth-restricted births following a hypertensive pregnancy were not. Neither a clinical diagnosis of birth asphyxia nor potentially asphyxiating birth events occurred more frequently among growth-restricted than among appropriately grown infants with CP. Major birth defects, particularly cerebral defects, occurred in an increasing proportion of CP with increasing growth deficit. The factor most predictive of CP in growth-restricted singletons was a major birth defect, present in 53% of markedly growth-restricted neonates with later CP. Defects observed in CP were similar whether growth restricted or not, except for an excess of isolated congenital microcephaly in those born growth restricted. The highest observed CP risk was in infants with both growth restriction and a major birth defect (8.9% of total CP in this gestational age group, 0.4% of controls: odds ratio, 30.9; 95% confidence interval, 7.0-136).

CONCLUSION

The risk of CP was increased in antenatally growth-restricted singletons born at or near term to normotensive mothers. In growth-restricted singletons, a major birth defect was the dominant predictor, associated with a 30-fold increase in odds of CP. Identification of birth defects in the growth-restricted fetus or neonate may provide significant prognostic information.

Innate hypothermia after hypoxic ischaemic delivery

The focus of this review is to collate the literature on the phenomenon of impaired thermal adaptation after hypoxic ischaemic (HI) delivery often culminating in hypothermia. This phenomenon appears different in severity and duration to a spontaneous postnatal fall in temperature observed after normal delivery. The original observation and contemporary descriptions of the temperature response to HI are described and a mechanism of action is proposed that may be utilised as a novel biomarker for HI.

The mechanisms and treatment of asphyxial encephalopathy

Acute post-asphyxial encephalopathy occurring around the time of birth remains a major cause of death and disability. The recent seminal insight that allows active neuroprotective treatment is that even after profound asphyxia (the “primary” phase), many brain cells show initial recovery from the insult during a short “latent” phase, typically lasting approximately 6 h, only to die hours to days later after a “secondary” deterioration characterized by seizures, cytotoxic edema, and progressive failure of cerebral oxidative metabolism. Although many of these secondary processes are potentially injurious, they appear to be primarily epiphenomena of the “execution” phase of cell death. Animal and human studies designed around this conceptual framework have shown that moderate cerebral hypothermia initiated as early as possible but before the onset of secondary deterioration, and continued for a sufficient duration to allow the secondary deterioration to resolve, has been associated with potent, long-lasting neuroprotection. Recent clinical trials show that while therapeutic hypothermia significantly reduces morbidity and mortality, many babies still die or survive with disabilities. The challenge for the future is to find ways of improving the effectiveness of treatment. In this review, we will dissect the known mechanisms of hypoxic-ischemic brain injury in relation to the known effects of hypothermic neuroprotection.

Astrocytes and microglia in acute cerebral injury underlying cerebral palsy associated with preterm birth

Cerebral palsy is one of the most devastating consequences of brain injury around the time of birth, and nearly a third of cases are now associated with premature birth. Compared with term babies, preterm babies have an increased incidence of complications that may increase the risk of disability, such as intraventricular hemorrhage, periventricular leukomalacia, sepsis, and necrotizing enterocolitis. The response to injury is highly dependent on brain maturity, and although cellular vulnerability is well documented, there is now evidence that premyelinating axons are also particularly sensitive to ischemic injury. In this review, we will explore recent evidence highlighting a central role for glia in mediating increased risk of disability in premature infants, including excessive activation of microglia and opening of astrocytic gap junction hemichannels in spreading injury after brain ischemia, in part likely involving release of adenosine triphosphate (ATP) and overactivation of purinergic receptors, particularly in white matter. We propose the hypothesis that inflammation-induced opening of connexin hemichannels is a key regulating event that initiates a vicious circle of excessive ATP release, which in turn propagates activation of purinergic receptors on microglia and astrocytes. This suggests that developing effective neuroprotective strategies for preterm infants requires a detailed understanding of glial responses.

Term neonatal encephalopathy antecedent cerebral palsy: a retrospective population-based study

OBJECTIVE

To compare the clinical profile of term-born cerebral palsy children with or without antecedent moderate to severe neonatal encephalopathy. We hypothesized that antecedent neonatal encephalopathy is associated with a spastic quadriparesis cerebral palsy clinical profile, a higher severity of functional motor impairment, and a greater number of associated comorbidities.

METHODS

Using the Quebec Cerebral Palsy Registry, neurologic subtype, Gross Motor Function Classification System stratification, and comorbidities were compared in children with cerebral palsy with and without antecedent neonatal encephalopathy. Differences between groups were evaluated using chi square analysis for categorical variables and student t test for continuous variables.

RESULTS

We identified 132 children with cerebral palsy born full term over a 4 year-interval (1999-2002 inclusive) within the Quebec Cerebral Palsy Registry, of which 44 (33%) had an antecedent neonatal encephalopathy. Spastic quadriplegia subtype of cerebral palsy and Gross Motor Function Classification System Level III-V (non-independent ambulation) were significantly associated with antecedent neonatal encephalopathy. The mean number of comorbidities experienced was not different in the two groups. Of five documented comorbidities, only severe communication difficulties were found to be associated (p < 0.05) with antecedent neonatal encephalopathy.

CONCLUSION

A pattern of increased neuromotor impairment, functional gross motor severity and possible communication difficulties was found in the 33% of children with cerebral palsy born at term and with a history of neonatal encephalopathy.