Cerebral palsy secondary to perinatal ischemic stroke

Generating Items for a Novel Bedside Dysphagia Screening Tool Post Acute Pediatric Stroke

Bedside dysphagia assessment protocols are not well developed in acute pediatric stroke unlike adults. The objective of this study was to identify items deemed relevant and feasible by expert consensus to inform the development of a bedside dysphagia screening tool for acute pediatric stroke. A two-phase study was conducted: (1) literature review and expert consultation generated a comprehensive list of dysphagia assessment items; (2) items were formatted in an online survey asking respondents opinion of relevance to acute pediatric stroke and feasibility for bedside administration by a trained health professional. The Dillman Tailored Design approach optimized response rate. Respondents were identified using the snowball method. Speech-language pathologists with > 2 years in pediatric dysphagia were invited to complete the survey. Demographic and practice variables were compared using univariate statistics. Item relevance and feasibility were made using binary or ordinal responses, combined to derive item-content validity indices (I-CVI) to guide item reduction. Items with I-CVI > 0.78 (excellent content validity) were moved forward to tool development. Of the 71 invited respondents, 57(80.3%) responded, of which 34(59.6%) were from North America. Sixty-one items were generated of which 4(6.6%) items were rated 'to keep'. These were face symmetry (I-CVI:0.89), salivary control (I-CVI:0.95), alertness (I-CVI:0.89) and choking (I-CVI:0.84). Of all respondents, 31(54.4%) endorsed swallowing trials, of which 25(80.6%) endorsed thin liquid by teaspoon (n = 17, 68%) or open cup (n = 20, 80%). We identified candidate items for bedside dysphagia screening with excellent content validity for acute pediatric stroke patients. Next steps include assessment of the psychometric value of each item in identifying dysphagia in children in the acute stage of recovery from stroke.

Neurological and Functional Outcomes after Pediatric Stroke

Pediatric stroke results in life-long morbidity for many patients, but the outcomes can vary depending on factors such as age of injury, or mechanism, size, and location of stroke. In this review, we summarize the current understanding of outcomes in different neurological domains (eg, motor, cognitive, language) for children with stroke of different mechanisms (ie, arterial ischemic stroke, cerebral sinus venous thrombosis, and hemorrhagic stroke), but with a focus on World Health Organization International Classification for Functioning, Disability, and Health (ICF-CY) framework for measuring health and disability for children and youth. We describe outcomes for the population as a whole and certain factors that may further refine prognostication.

Development and Validation of a Prediction Model for Perinatal Arterial Ischemic Stroke in Term Neonates

IMPORTANCE

Perinatal arterial ischemic stroke (PAIS) is a focal brain injury in term neonates that is identified postnatally but is presumed to occur near the time of birth. Many pregnancy, delivery, and fetal factors have been associated with PAIS, but early risk detection is lacking; thus, targeted treatment and prevention efforts are currently limited.

OBJECTIVE

To develop and validate a diagnostic risk prediction model that uses common clinical factors to predict the probability of PAIS in a term neonate.

DESIGN, SETTING, AND PARTICIPANTS

In this diagnostic study, a prediction model was developed using multivariable logistic regression with registry-based case data collected between January 2003, and March 2020, from the Alberta Perinatal Stroke Project, Canadian Cerebral Palsy Registry, International Pediatric Stroke Study, and Alberta Pregnancy Outcomes and Nutrition study. Criteria for inclusion were term birth and no underlying medical conditions associated with stroke diagnosis. Records with more than 20% missing data were excluded. Variable selection was based on peer-reviewed literature. Data were analyzed in September 2021.

EXPOSURES

Clinical pregnancy, delivery, and neonatal factors associated with PAIS as common data elements across the 4 registries.

MAIN OUTCOMES AND MEASURES

The primary outcome was the discriminative accuracy of the model predicting PAIS, measured by the concordance statistic (C statistic).

RESULTS

Of 2571 term neonates in the initial analysis (527 [20%] case and 2044 [80%] control individuals; gestational age range, 37-42 weeks), 1389 (54%) were male, with a greater proportion of males among cases compared with controls (318 [60%] vs 1071 [52%]). The final model was developed using 1924 neonates, including 321 cases (17%) and 1603 controls (83%), and 9 clinical factors associated with risk of PAIS in term neonates: maternal age, tobacco exposure, recreational drug exposure, preeclampsia, chorioamnionitis, intrapartum maternal fever, emergency cesarean delivery, low 5-minute Apgar score, and male sex. The model demonstrated good discrimination between cases and controls (C statistic, 0.73; 95% CI, 0.69-0.76) and good model fit (Hosmer-Lemeshow P = .20). Internal validation techniques yielded similar C statistics (0.73 [95% CI, 0.69-0.77] with bootstrap resampling, 10-fold cross-validated area under the curve, 0.72 [bootstrap bias-corrected 95% CI, 0.69-0.76]), as did a sensitivity analysis using cases and controls from Alberta, Canada, only (C statistic, 0.71; 95% CI, 0.65-0.77).

CONCLUSIONS AND RELEVANCE

The findings suggest that clinical variables can be used to develop and internally validate a model to predict the risk of PAIS in term neonates, with good predictive performance and strong internal validity. Identifying neonates with a high probability of PAIS who could then be screened for early diagnosis and treatment may be associated with reductions in lifelong morbidity for affected individuals and their families.

Risk factors for perinatal arterial ischaemic stroke: a large case-control study

AIM

To identify maternal, obstetric, and neonatal risk factors related to perinatal arterial ischaemic stroke (PAIS) diagnosed within 28 days after birth and to understand the underlying pathophysiology.

METHOD

For case and control ascertainment, we used active surveillance in 345 paediatric hospitals and a population-based perinatal database for quality assurance of hospital care. We analysed complete cases of PAIS using logistic regression. Multivariate analysis was guided by a directed acyclic graph.

RESULTS

After exclusion of records with missing data, we analysed 134 individuals with PAIS and 576 comparison individuals. In univariate analysis, male sex, preterm birth (<37wks gestational age), small for gestational age (SGA), low umbilical artery pH (<7.1), low 5-minute-Apgar score (<7), multiple pregnancies, hypoxia, intubation/mask ventilation, nulliparity, Caesarean section, vaginal-operative delivery, chorioamnionitis, and oligohydramnios were associated with an increased risk. Mutual adjustment yielded male sex (odds ratio [OR] 1.81; 95% confidence interval [CI] 1.20-2.73), multiple birth (OR 3.22; 95% CI 1.21-8.58), chorioamnionitis (OR 9.89; 95% CI 2.88-33.94), preterm birth (OR 1.86; 95% CI 1.01-3.43), and SGA (OR 3.05; 95% CI 1.76-5.28) as independent risk factors.

INTERPRETATION

We confirmed the increased risk in males and the role of chorioamnionitis and SGA for PAIS, pointing to the importance of inflammatory processes and fetal-placental insufficiency. Multiple birth and preterm birth were additional risk factors.

WHAT THIS PAPER ADDS

Chorioamnionitis and small for gestational age (SGA) precede perinatal arterial ischaemic stroke (PAIS). Chorioamnionitis and SGA are independent risk factors for PAIS. Inflammatory processes and fetal-placental insufficiency are the likely underlying mechanisms. Multiple birth and preterm birth are additional risk factors.

Feeding and swallowing impairment in children with stroke and unilateral cerebral palsy: a systematic review

AIM

This systematic review targeted frequency estimates of dysphagia (feeding and swallowing problems), related health outcomes, and caregiver burden in children with stroke or unilateral cerebral palsy (CP).

METHOD

Six electronic databases were searched from their inception to November 2017 along with a manual search of eight relevant journals. Two blinded raters assessed abstracts and full articles for eligibility. Discrepancies were resolved by consensus. Accepted articles were evaluated for quality. Data were extracted and analysed descriptively.

RESULTS

Of 1660 abstracts, five met inclusion criteria, of which three focused on stroke and two unilateral CP. Across studies, operational definitions of feeding and swallowing varied. Insufficient details were provided on assessment methods and timing. Reported frequencies of dysphagia ranged from 24.2% to 88.6%. One study reported dysphagia-related health outcomes and none reported caregiver burden.

INTERPRETATION

These results suggest that dysphagia is common in children with stroke and unilateral CP; however, its frequency is yet unknown as is its impact on health and caregiver burden. Availability of a standardized tool to identify dysphagia in these children accurately is a recommended first step to address this evidence gap.

WHAT THIS PAPER ADDS

There is limited data on the incidence of dysphagia after childhood stroke and unilateral cerebral palsy. Available evidence shows reported dysphagia frequencies from 24.2% to 88.6%. Only one study reported on dysphagia-related health outcomes. No study reported on caregiver burden.

Maternal thyroid disorder in pregnancy and risk of cerebral palsy in the child: a population-based cohort study

Background

Cerebral palsy is the most frequent motor disability in childhood, but little is known about its etiology. It has been suggested that cerebral palsy risk may be increased by prenatal thyroid hormone disturbances. The objective of this study was to investigate whether maternal thyroid disorder is associated with increased risk of cerebral palsy.

Methods

A population-based cohort study using two study populations. 1) 1,270,079 children born in Denmark 1979–2007 identified in nationwide registers, and 2) 192,918 children born 1996–2009 recruited into the Danish National Birth Cohort and The Norwegian Mother and Child Cohort study, combined in the MOthers and BAbies in Norway and Denmark (MOBAND) collaboration cohort. Register-based and self-reported information on maternal thyroid disorder was studied in relation to risk of cerebral palsy and its unilateral and bilateral spastic subtypes using multiple logistic regression. Children were followed from the age of 1 year to the age of 6 years, and cerebral palsy was identified in nationwide registers with verified diagnoses.

Results

In register data, hypothyroidism was recognized in 12,929 (1.0%), hyperthyroidism in 9943 (0.8%), and unclassifiable thyroid disorder in 753 (< 0.1%) of the mothers. The odds ratio for an association between maternal thyroid disorder and bilateral spastic cerebral palsy was 1.0 (95% CI: 0.7–1.5). Maternal thyroid disorder identified during pregnancy was associated with elevated risk of unilateral spastic cerebral palsy (odds ratio 3.1 (95% CI: 1.2–8.4)). In MOBAND, 3042 (1.6%) of the mothers reported a thyroid disorder in pregnancy, which was not associated with cerebral palsy overall (odds ratio 1.2 (95% CI: 0.6–2.4)).

Conclusions

Maternal thyroid disorder overall was not related to bilateral spastic cerebral palsy, but maternal thyroid disorder identified in pregnancy was associated with increased risk of unilateral spastic cerebral palsy. These findings should be replicated in studies making use of maternal blood samples.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1152-5) contains supplementary material, which is available to authorized users.

Early Intensive Leg Training to Enhance Walking in Children With Perinatal Stroke: Protocol for a Randomized Controlled Trial

BACKGROUND

Development of motor pathways is modulated by activity in these pathways, when they are maturing (ie, critical period). Perinatal stroke injures motor pathways, including the corticospinal tracts, reducing their activity and impairing motor function. Current intervention for the lower limb emphasizes passive approaches (stretching, braces, botulinum toxin injections). The study hypothesis was that intensive, early, child-initiated activity during the critical period will enhance connectivity of motor pathways to the legs and improve motor function.

OBJECTIVE

The study objective was to determine whether early intervention with intensive activity is better than standard care, intervention delivered during the proposed critical period is better than after, and the outcomes are different when the intervention is delivered by a physical therapist in an institution vs. a parent at home.

DESIGN

A prospective, delay-group, single-blind, randomized controlled trial (RCT) and a parallel, cohort study of children living beyond commuting distance and receiving an intervention delivered by their parent.

SETTING

The RCT intervention was provided in university laboratories, and parent training was provided in the childs home.

PARTICIPANTS

Children 8 months to 3 years old with MRI-confirmed perinatal ischemic stroke and early signs of hemiparesis.

INTERVENTION

Intensive, play-based leg activity with weights for the affected leg and foot, 1 hour/day, 4 days/week for 12 weeks.

MEASUREMENTS

The primary outcome was the Gross Motor Function Measure-66 score. Secondary outcomes were motion analysis of walking, full-day step counts, motor evoked potentials from transcranial magnetic stimulation, and patellar tendon reflexes.

LIMITATIONS

Inter-individual heterogeneity in the severity of the stroke and behavioral differences are substantial but measurable. Differences in intervention delivery and assessment scoring are minimized by standardization and training.

CONCLUSIONS

The intervention, contrary to current practice, could change physical therapy interventions for children with perinatal stroke.

Spatial Orientation and Navigation in Children With Perinatal Stroke

As a focal injury in an otherwise healthy child, perinatal stroke provides a clinical model of developmental brain plasticity. In this study, we report evidence that children with perinatal periventricular venous infarcts perform as well as control children on a video game that tests navigation abilities. In addition, children with a history of perinatal arterial strokes overcame initial deficits in navigation performance after additional practice. These findings lend support to the hypothesis that a complex cognitive skill dependent on a distributed neural network with prolonged maturation, such as navigation, may demonstrate resilience after early brain injury.

Advancing non-invasive neuromodulation clinical trials in children: Lessons from perinatal stroke

Applications of non-invasive brain stimulation including therapeutic neuromodulation are expanding at an alarming rate. Increasingly established scientific principles, including directional modulation of well-informed cortical targets, are advancing clinical trial development. However, high levels of disease burden coupled with zealous enthusiasm may be getting ahead of rational research and evidence. Experience is limited in the developing brain where additional issues must be considered. Properly designed and meticulously executed clinical trials are essential and required to advance and optimize the potential of non-invasive neuromodulation without risking the well-being of children and families. Perinatal stroke causes most hemiplegic cerebral palsy and, as a focal injury of defined timing in an otherwise healthy brain, is an ideal human model of developmental plasticity. Advanced models of how the motor systems of young brains develop following early stroke are affording novel windows of opportunity for neuromodulation clinical trials, possibly directing neuroplasticity toward better outcomes. Reviewing the principles of clinical trial design relevant to neuromodulation and using perinatal stroke as a model, this article reviews the current and future issues of advancing such trials in children.

Motor and cognitive outcome after specific early lesions of the brain - a systematic review

The aim of this systematic review was to study motor and cognitive outcome in infants with severe early brain lesions and to evaluate effects of side of the lesion, sex, and social economic status on outcome. A literature search was performed using the databases Pubmed and Embase. Included studies involved infants with either cystic periventricular leukomalacia (cPVL), preterm, or term stroke (i.e. parenchymal lesion of the brain). Outcome was expressed as cerebral palsy (CP) and intellectual disability (mental retardation). Median prevalence rates of CP after cPVL, preterm, and term stroke were 86%, 71%, and 29% respectively; of intellectual disability 50%, 27%, and 33%. Most infants with cPVL developed bilateral CP, those with term stroke unilateral CP, whereas after preterm stroke bilateral and unilateral CP occurred equally often. Information on the effects of sex and social economic status on outcome after specific brain lesions was very limited. Our findings show that the risk for CP is high after cPVL, moderate after preterm stroke, and lowest after term stroke. The risk for intellectual disability after an early brain lesion is lower than that for CP. Predicting outcome at individual level remains difficult; new imaging techniques may improve predicting developmental trajectories.

Cortical activation and inter-hemispheric sensorimotor coherence in individuals with arm dystonia due to childhood stroke

OBJECTIVE

Dystonia is a disabling motor disorder often without effective therapies. To better understand the genesis of dystonia after childhood stroke, we analyzed electroencephalographic (EEG) recordings in this population.

METHODS

Resting spectral power of EEG signals over bilateral sensorimotor cortices (Powrest), resting inter-hemispheric sensorimotor coherence (Cohrest), and task-related changes in power (TRPow) and coherence (TRCoh) during wrist extension were analyzed in individuals with dystonia (age 20±3years) and healthy volunteers (age 17±5years).

RESULTS

Ipsilesional TRPow decrease was significantly lower in patients than controls during the more affected wrist task. Force deficits of the affected wrist correlated with reduced alpha TRPow decrease on the ipsilesional and not the contralesional hemisphere. Cohrest was significantly lower in patients than controls, and correlated with more severe dystonia and poorer hand function. Powrest and TRCoh were similar between groups.

CONCLUSIONS

The association between weakness and cortical activation during wrist extension highlights the importance of ipsilesional sensorimotor activation on function. Reduction of Cohrest in patients reflects a loss of inter-hemispheric connectivity that may result from structural changes and neuroplasticity, potentially contributing to the development of dystonia.

SIGNIFICANCE

Cortical and motor dysfunction are correlated in patients with childhood stroke and may in part explain the genesis of dystonia.

Early diagnosis and early intervention in cerebral palsy

This paper reviews the opportunities and challenges for early diagnosis and early intervention in cerebral palsy (CP). CP describes a group of disorders of the development of movement and posture, causing activity limitation that is attributed to disturbances that occurred in the fetal or infant brain. Therefore, the paper starts with a summary of relevant information from developmental neuroscience. Most lesions underlying CP occur in the second half of gestation, when developmental activity in the brain reaches its summit. Variations in timing of the damage not only result in different lesions but also in different neuroplastic reactions and different associated neuropathologies. This turns CP into a heterogeneous entity. This may mean that the best early diagnostics and the best intervention methods may differ for various subgroups of children with CP. Next, the paper addresses possibilities for early diagnosis. It discusses the predictive value of neuromotor and neurological exams, neuroimaging techniques, and neurophysiological assessments. Prediction is best when complementary techniques are used in longitudinal series. Possibilities for early prediction of CP differ for infants admitted to neonatal intensive care and other infants. In the former group, best prediction is achieved with the combination of neuroimaging and the assessment of general movements, in the latter group, best prediction is based on carefully documented milestones and neurological assessment. The last part reviews early intervention in infants developing CP. Most knowledge on early intervention is based on studies in high-risk infants without CP. In these infants, early intervention programs promote cognitive development until preschool age; motor development profits less. The few studies on early intervention in infants developing CP suggest that programs that stimulate all aspects of infant development by means of family coaching are most promising. More research is urgently needed.

Cognitive outcomes following arterial ischemic stroke in infants and children

This study sought to investigate cognitive outcomes following pediatric arterial ischemic stroke and explore predictors. Participants included 36 children with perinatal or childhood arterial ischemic stroke and a comparison group of 15 children with asthma. Outcomes included cognitive ability, executive functions, and neurological function (Pediatric Stroke Outcome Measure). Magnetic resonance imaging measured lesion location and volume. Mean cognitive scores were at the low end of the average range. Children with arterial ischemic stroke performed significantly below normative populations and significantly below the asthma group on inhibitory control (Cohen's d = .68). Both the Pediatric Stroke Outcome Measure and lesion volume were negatively correlated with cognitive outcome (Spearman r = -.01 to -.42 Pediatric Stroke Outcome Measure; r =-.14 to -.32 Volume). Following arterial ischemic stroke, children performed at the low end of the average range on measures of cognitive functioning. Cognitive outcomes depend on a variety of factors.

Characteristics of bilateral hand function in individuals with unilateral dystonia due to perinatal stroke: sensory and motor aspects

The authors assessed bilateral motor and sensory function in individuals with upper limb dystonia due to unilateral perinatal stroke and explored interrelationships of motor function and sensory ability. Reach kinematics and tactile sensation were measured in 7 participants with dystonia and 9 healthy volunteers. The dystonia group had poorer motor (hold time, reach time, shoulder/elbow correlation) and sensory (spatial discrimination, stereognosis) outcomes than the control group on the nondominant side. On the dominant side, only sensation (spatial discrimination, stereognosis) was poorer in the dystonia group compared with the control group. In the dystonia group, although sensory and motor outcomes were uncorrelated, dystonia severity was related to poorer stereognosis, longer hold and reach times, and decreased shoulder/elbow coordination. Findings of bilateral sensory deficits in dystonia can be explained by neural reorganization. Visual compensation for somatosensory changes in the nonstroke hemisphere may explain the lack of bilateral impairments in reaching.

Evidence for therapeutic intervention in the prevention of cerebral palsy: hope from animal model research

Knowledge translation, as defined by the Canadian Institute of Health Research, is defined as the exchange, synthesis, and ethically sound application of knowledge--within a complex system of interactions among researchers and users--to accelerate the capture of the benefits of research through improved health, more effective services and products, and a strengthened healthcare system. The requirement for this to occur lies in the ability to continue to determine mechanistic actions at the molecular level, to understand how they fit at the in vitro and in vivo levels, and for disease states, to determine their safety, efficacy, and long-term potential at the preclinical animal model level. In this regard, particularly as it relates to long-term disabilities such as cerebral palsy that begin in utero, but only express their full effect in adulthood, animal models must be used to understand and rapidly evaluate mechanisms of injury and therapeutic interventions. In this review, we hope to provide the reader with a background of animal data upon which therapeutic interventions for the prevention and treatment of cerebral palsy, benefit this community, and increasingly do so in the future.

Can noninvasive brain stimulation measure and modulate developmental plasticity to improve function in stroke-induced cerebral palsy?

The permanent nature of motor deficits is a consistent cornerstone of cerebral palsy definitions. Such pessimism is disheartening to children, families, and researchers alike and may no longer be appropriate for it ignores the fantastic plastic potential of the developing brain. Perinatal stroke is presented as the ideal human model of developmental neuroplasticity following distinct, well-defined, focal perinatal brain injury. Elegant animal models are merging with human applied technology methods, including noninvasive brain stimulation for increasingly sophisticated models of plastic motor development following perinatal stroke. In this article, how potential central therapeutic targets are identified and potentially modulated to enhance motor function within these models is discussed. Also, future directions and emerging clinical trials are reviewed.

Arteriopathy, D-dimer, and risk of poor neurologic outcome in childhood-onset arterial ischemic stroke

OBJECTIVE

To assess whether acute findings of cerebral arteriopathy, large infarct, and acutely elevated plasma D-dimer levels are independently prognostic of poor long-term neurologic outcome as measured at ≥ 1 year post-event in children with arterial ischemic stroke (AIS).

STUDY DESIGN

Sixty-one patients with childhood-onset (ie, >28 days of life) AIS were enrolled in a single-institution cohort study at Children's Hospital Colorado between February 2006 and June 2011. Data on demographic and diagnostic characteristics, antithrombotic treatments, and outcomes were systematically collected.

RESULTS

Cerebral arteriopathy and D-dimer levels >500 ng/mL (a measure of coagulation activation) were identified acutely in 41% and 31% of the cohort, respectively. Anticoagulation was administered in the acute period post-event in 40% of the children, in the subacute period in 43%, and in the chronic period in 28%. When not receiving anticoagulation, patients were routinely treated with aspirin 2-5 mg/kg once daily for a minimum of 1 year. Death, major bleeding (including intracranial hemorrhage), and recurrent AIS were infrequent. The Pediatric Stroke Outcome Measure at 1 year demonstrated poor outcome in 54% of the children. Acute cerebral arteriopathy and elevated D-dimer level were identified as putative prognostic factors for poor outcome; after adjustment for D-dimer, arteriopathy was an independent prognostic indicator (OR, 19.0; 95% CI, 1.6-229.8; P = .02).

CONCLUSION

Arteriopathy and coagulation activation are highly prevalent in the acute period of childhood AIS. Although recurrent AIS and intracranial hemorrhage were infrequent in our cohort, one-half of children experienced a poor neurologic outcome at 1 year, the risk of which was increased by acute arteriopathy. Substantiation of these findings in multi-institutional cohort studies is warranted, toward risk stratification in childhood-onset AIS.

Modeling developmental plasticity after perinatal stroke: defining central therapeutic targets in cerebral palsy

Perinatal stroke is presented as the ideal human model of developmental neuroplasticity. The precise timing, mechanisms, and locations of specific perinatal stroke diseases provide common examples of well defined, focal, perinatal brain injuries. Motor disability (hemiparetic cerebral palsy) constitutes the primary adverse outcome and the focus of models explaining how motor systems develop in health and after early injury. Combining basic science animal work with human applied technology (functional magnetic resonance imaging, diffusion tensor imaging, and transcranial magnetic stimulation), a model of plastic motor development after perinatal stroke is presented. Potential central therapeutic targets are revealed. The means to measure and modulate these targets, including evidence-based rehabilitation therapies and noninvasive brain stimulation, are suggested. Implications for clinical trials and future directions are discussed.

Treatment of congenital hemiparesis with pediatric constraint-induced movement therapy

To determine efficacy of pediatric Constraint-Induced Movement therapy, 20 children with congenital hemiparesis (ages 2 to 6 years) were randomly assigned to receive the treatment or usual care. Controls crossed over to the therapy after 6 months. Children receiving the therapy first exhibited emergence of more new classes of motor patterns and skills (eg, crawling, thumb-forefinger prehension; 6.4 vs 0.02, P < .0001, effect size d = 1.3), and demonstrated significant gains in spontaneous use of the more affected arm at home (2.2 vs 0.1, P < .0001, d = 3.8) and in a laboratory motor function test. Depending on the measure, benefits were maintained (range, no loss to 68% retention over 6 months). When controls crossed over to the therapy, they exhibited improvements as great as or greater than those receiving therapy first. Thus, Constraint-Induced Movement therapy appears to be efficacious for young children with hemiparesis consequent to congenital stroke.

Pediatric arterial ischemic stroke

Arterial ischemic stroke (AIS) is a rare disorder in children. Research suggests that risk factors, outcomes, and presentation are different from those of adult stroke. In particular, prothrombotic abnormalities and large vessel arteriopathies that are nonatherosclerotic seem to play a large role in the pathogenesis of childhood AIS. This review examines the epidemiology and etiologies of neonatal and childhood AIS and provides a detailed discussion of approaches to the clinical characterization, diagnostic evaluation, and management. Long-term outcomes of recurrent AIS and neuromotor, speech, cognitive, and behavioral deficits are considered. Emphasis is on evidence underlying current knowledge and key questions for further investigation.

Altered pain and thermal sensation in subjects with isolated parietal and insular cortical lesions

Studies of sensory function following cortical lesions have often included lesions which multiple cortical, white matter, and thalamic structures. We now test the hypothesis that lesions anatomically constrained to particular insular and parietal structures and their subjacent white matter are associated with different patterns of sensory loss. Sensory loss was measured by quantitative sensory testing (QST), and evaluated statistically within patients relative to normal values. All seven subjects with insular and/or parietal lesions demonstrated thermal hypoesthesia, although the etiology of the lesions was heterogeneous. Cold and heat hypoalgesia were only found in the subject with the most extensive parietal and insular lesion, which occurred in utero. Cold allodynia occurred clinically and by thresholds in two subjects with isolated ischemic lesions of the posterior insular/retroinsular cortex, and by thresholds in two subjects with a lesion of parietal cortex with little or no insular involvement. Central pain occurred in the two subjects with clinical allodynia secondary to isolated lesions of the posterior insular/retroinsular cortex, which spared the anterior and posterior parietal cortex. These results suggest that nonpainful cold and heat sensations are jointly mediated by parietal and insular cortical structures so that lesions anywhere in this system may diminish sensitivity. In contrast, thermal pain is more robust requiring larger cortical lesions of these same structures to produce hypoalgesia. In addition, cold allodynia can result from restricted lesions that also produce thermal hypoesthesia, but not from all such lesions.

Diagnosis of perinatal stroke II: mechanisms and clinical phenotypes

INTRODUCTION

Here (and in an accompanying article dealing with definitions, differential diagnosis and registration), a structured sequential diagnostic flow is proposed to discern clinical phenotypes for perinatal stroke, including arterial ischaemic stroke (AIS), cerebral sinovenous thrombosis (CSVT) and haemorrhagic stroke.

MATERIAL AND RESULTS

For neonatal AIS, the diagnostic sequence is infection, trauma, embolism, arteriopathy, other, primary thrombosis and unclassifiable; for neonatal CSVT, the sequence is infection, trauma, venopathy, other, primary thrombosis and unclassifiable. The proposed hierarchical diagnostic flows are an initial step towards a standard for registration of the causes of neonatal stroke. Such standardization should guide attempts at prevention and intervention. An extensive literature search and study of a retrospective cohort of 134 newborn infants with stroke suggest that embolism is the most common identifiable cause for stroke in general (25%), preceding trauma (10%) and infection (8%). Other causes, such as asphyxia, acute blood loss, extracorporeal membrane oxygenation, genetic disorders or prothrombotic conditions, are seen in <5% of cases. For neonatal AIS, the presence of an embolic phenotype is 33% in this cohort. The designation unclassifiable scored 34% for the entire stroke group and 25% for neonatal AIS. Complex arterial stroke with multiple arteries involved is often seen when the underlying cause is infection, cranial trauma or embolism. One important conclusion is that a means of prevention is avoidance of embolism from thrombosis outside the brain.

CONCLUSION

To prevent the occurrence and recurrence of neonatal ischaemic stroke, clinicians must develop a standardized diagnostic approach that results in characterization of the clinical phenotype.

Evolution of unilateral perinatal arterial ischemic stroke on conventional and diffusion-weighted MR imaging

BACKGROUND AND PURPOSE

Knowledge of the sequence of signal-intensity (SI) changes on conventional and diffusion-weighted MR imaging (DWI) following perinatal arterial ischemic stroke (PAIS) is limited, adding to the difficulty in timing the onset of PAIS. We hypothesized that SI changes seen on early sequential MR imaging following PAIS should follow a similar time course. The aim of this study was to evaluate the time course of SI changes by using a simple classification that could be assessed visually from conventional imaging and DWI in term-born neonates with symptomatic unilateral PAIS.

MATERIALS AND METHODS

Infants > or =36 weeks gestation with unilateral PAIS in the territory of a main cerebral artery with a first MR imaging performed within the first postnatal month were included in this study. All subsequent scans up to 3 months postnatal age were also evaluated. For the conventional MR imaging scans, a visual SI scoring system was used (-1 = lower, 0 = equal, 1 = higher) compared with the contralesional hemisphere. For the DWIs, SI of the infarcted tissue was classified into the 3 groups: 1) severe hyperintensity (HI), 2) moderate and mild HI, and 3) no HI.

RESULTS

We analyzed 43 scans (mean age at first scanning, 4 days) from 21 term infants. Changes in SI on conventional T1 and T2 images were remarkably consistent among infants. The cortex was of low SI on T1 and high SI on T2 until day 6 when SIs reversed and cortical highlighting was seen for 1-2 months. The white matter was high SI on T1 in the first 8-9 days and on T2 for >2 weeks before becoming low SI. Secondary SI changes remote from the infarction were seen in the thalamus and brain stem in the first week, and atrophy was seen after 4 weeks. All DWIs showed high SI of the affected region until at least day 4, which fell to equal or below that of the contralesional hemisphere by day 12.

CONCLUSIONS

The pattern of SI change on conventional imaging and DWI following PAIS was remarkably consistent among patients, suggesting that PAIS in symptomatic term-born infants occurs within a very limited timeframe around birth.

Advances in perinatal ischemic stroke

Increasingly distinct patterns of focal ischemic injury in the fetal and perinatal brain are recognized. Improved classification has afforded advances in risk factor identification, pathophysiology hypotheses, outcome prediction, and potential avenues for intervention. Cerebrovascular occlusion leading to perinatal stroke may be arterial or venous, symptomatic or subclinical, and it can occur across multiple time frames. Distinguishing causative factors from mere associations represents a major challenge with important implications for studies of pathogenesis. The adverse outcomes suffered by most children highlight the need for further research. Reviewed here are the current understandings, recent advancements, and future directions for research in perinatal ischemic stroke.

Delayed neural network degeneration after neonatal hypoxia-ischemia

OBJECTIVE

Clinical magnetic resonance studies show delayed and ongoing neurodegeneration after neonatal hypoxia-ischemia (HI), but the mechanisms and timing of this neurodegeneration remain unclear. We used ex vivo diffusion tensor imaging (DTI) and brain neuropathology to determine whether selective injury to white matter tracts occurs after neonatal HI in mice resulting in neural system-associated attrition in remote regions and at delayed times.

METHODS

The Rice-Vannucci model (unilateral carotid ligation + 45 minutes of hypoxia FiO(2) = 0.08) was used to cause brain injury in postnatal day 7 (p7) C57BL6 mice, and ex vivo DTI and correlative neuropathology were performed at p8, p11, p15, p21, p28, and p42.

RESULTS

DTI provides excellent contrast visualization of unmyelinated white matter in the immature mouse brain. Severe ipsilateral injury to the hippocampus is seen with both histopathology and diffusion-weighted magnetic resonance imaging 24 hours after injury. Injury to axons is evident 24 hours after HI in the hippocampal alveus. By p11 and continuing until p28, the ipsilateral fimbria fornix degenerates. At p15, there is injury and loss of axons entering the ipsilateral septal nucleus followed by ipsilateral septal atrophy. Volume loss in the hippocampus is rapid and severe, but is subacute and significantly slower in the ipsilateral septum. Neonatal HI also interrupts the normal developmental increase in fractional anisotropy in the ipsilateral fimbria but not in the contralateral fimbria from p8 to p42.

INTERPRETATION

In neonatal brain, there is progressive systems-preferential injury after HI. DTI allows unparalleled visualization of this neural network-associated attrition so that it can be followed longitudinally in developing brain.

Is cerebral palsy preventable?

PURPOSE OF REVIEW

To use evidence of good medical quality to update information on strategies for prevention of cerebral palsy, and on the success of these preventive efforts to date.

RECENT FINDINGS

Causes of cerebral palsy, and therefore promising approaches to prevention, differ by gestational age group and by clinical subtype. Neuroimaging and neuropathology indicate the importance of white matter disorders and of ischemic stroke in cerebral palsy; birth asphyxia, congenital malformations, placental pathology, and genetic variants also contribute to cerebral palsy risk. Multiplicity of risk factors markedly increases risk. Recent studies indicate that mild hypothermia lessens cerebral palsy risk in term infants with moderate neonatal encephalopathy, and the possibility that administration of magnesium sulphate to women in preterm labor may aid in primary prevention of cerebral palsy in very preterm infants.

SUMMARY

Past efforts to prevent cerebral palsy have not had the benefits sought, but recent results provide new hope and new challenges.

Pediatric arterial ischemic stroke

Arterial ischemic stroke (AIS) is a rare disorder in children. Research suggests that risk factors, outcomes, and presentation are different from those of adult stroke. In particular, prothrombotic abnormalities and large vessel arteriopathies that are nonatherosclerotic seem to play a large role in the pathogenesis of childhood AIS. This review examines the epidemiology and etiologies of neonatal and childhood AIS and provides a detailed discussion of approaches to the clinical characterization, diagnostic evaluation, and management. Long-term outcomes of recurrent AIS and neuromotor, speech, cognitive, and behavioral deficits are considered. Emphasis is on evidence underlying current knowledge and key questions for further investigation.

Ischemic perinatal stroke: summary of a workshop sponsored by the National Institute of Child Health and Human Development and the National Institute of Neurological Disorders and Stroke

Ischemic perinatal stroke is a disorder associated with significant long-term neurologic morbidity. With an estimated incidence of 1 in 2300 to 5000 births, stroke is more likely to occur in the perinatal period than at any time in childhood. The incidence of ischemic perinatal stroke ranks second only to that of strokes in the elderly population. Although ischemic perinatal stroke is a well-recognized disorder, many aspects remain to be studied. There is no consensus on its terminology, definition, or classification. Several risk factors have been identified, but their precise roles in causing stroke are not well understood. There are no reliable predictors of ischemic perinatal stroke on which to base prevention or treatment strategies. To review these important issues and propose a research agenda, the National Institute of Child Health and Human Development and the National Institute of Neurological Disorders and Stroke convened a workshop in August 2006. This article provides a summary of the workshop.

Antioxidant Status Alters Levels of Fas-Associated Death Domain-Like IL-1B-Converting Enzyme Inhibitory Protein following Neonatal Hypoxia-Ischemia

Activation of Fas death receptor (Fas DR) signaling cascade is seen after neonatal hypoxia-ischemia (HI). Cell survival is favored when signaling through the death-inducing signaling complex and cleavage of caspase 8 to its active form is blocked by FLIP, a dominant negative of caspase 8. H2O2 quickly downregulates expression of FLIP. Neonatal mice overexpressing glutathione peroxidase (GPx) have less injury and less H2O2 accumulation compared with neonatal mice overexpressing superoxide dismutase (SOD) or wild-type (WT) littermates. Expression of both FLIP(L) and FLIP(S) is increased in GPx-oxerexpressing mice relative to WT mice at 24 h and relative to SOD-overexpressing mice at 2 and 24 h following neonatal HI (ANOVA, p < 0.05). There is an increase in Fas DR expression at 24 h in both WT and GPx-overexpressing mice and significant differences between WT and SOD-overexpressing mice (ANOVA, p < 0.01). There is no difference in FADD expression among the 3 groups 24 h after HI. At 24 h following HI, the ratio of FLIP to Fas DR expression supports a significant negative correlation with injury score (r2 = 0.99, slope = -4.01), and expression of both the active fragment of caspase 8 and caspase 8 activity is increased in SOD overexpressors compared to GPx overexpressors at 24 h after HI (ANOVA, p < 0.05). The overall degree of injury previously seen in these 3 strains correlates well with changes in expression of Fas DR signaling proteins favoring neuroprotection in the GPx-overexpressing mice, i.e. increased FLIP expression and decreased caspase 8 activity compared to SODtg mice. The mechanism by which antioxidant status alters FLIP levels following neonatal HI may be related to the ability to detoxify H2O2 produced following neonatal HI.