The development of drawing in children with congenital focal brain injury: evidence for limited functional recovery

Arterial Presumed Perinatal Ischemic Stroke: A Mini Review and Case Report of Cognitive and Speech-Language Profiles in a 5-Year-Old Girl

Arterial presumed perinatal ischemic stroke is a type of perinatal stroke that emerges due to late or delayed diagnostics of perinatal or neonatal arterial ischemic stroke. It is usually recognized before one year of life due to hemiparesis. This injury may lead to cognitive, behavioral, or motor symptoms, and life-long neurodevelopmental disabilities. In this case report, we describe a five-year-old girl with a history of arterial presumed perinatal ischemic stroke in the left hemisphere, which adversely affected her cognitive and language outcomes. The girl's cognitive development has been uneven, ranging from below average to average, and she had specific language acquisition deficits in comprehension, vocabulary, morphology, use of complex syntax, and narrative structure. The obtained results point to the specificity of each child whose development is influenced not only by the timing of the brain lesion and the degree of damage, but also by the child's neurobiological capacity. In addition, we provide an updated review of the literature that includes information on epidemiology, risk factors, diagnostics, clinical manifestations, outcomes, and potential therapies. The present article highlights the importance of early intervention and systematic monitoring of children with perinatal stroke with the aim of improving the child's development.

From Hemispheric Asymmetry through Sensorimotor Experiences to Cognitive Outcomes in Children with Cerebral Palsy

Recent neuroimaging studies allowed us to explore abnormal brain structures and interhemispheric connectivity in children with cerebral palsy (CP). Behavioral researchers have long reported that children with CP exhibit suboptimal performance in different cognitive domains (e.g., receptive and expressive language skills, reading, mental imagery, spatial processing, subitizing, math, and executive functions). However, there has been very limited cross-domain research involving these two areas of scientific inquiry. To stimulate such research, this perspective paper proposes some possible neurological mechanisms involved in the cognitive delays and impairments in children with CP. Additionally, the paper examines the ways motor and sensorimotor experience during the development of these neural substrates could enable more optimal development for children with CP. Understanding these developmental mechanisms could guide more effective interventions to promote the development of both sensorimotor and cognitive skills in children with CP.

Non-verbal Intelligence in Unilateral Perinatal Stroke Patients With and Without Epilepsies

Background: The risk factors for impaired cognitive development after unilateral perinatal stroke are poorly understood. Non-verbal intelligence seems to be at particular risk, since language can shift to the right hemisphere and may thereby reduce the capacity of the right hemisphere for its originary functions. Pharmaco-refractory epilepsies, a frequent complication of perinatal strokes, often lead to impaired intelligence. Yet, the role of well-controlled epilepsies is less well-understood. Here, we investigated whether well-controlled epilepsies, motor impairment, lesion size, lesion side, and lateralization of language functions influence non-verbal functions. Methods: We recruited 8 patients with well-controlled epilepsies (9-26 years), 15 patients without epilepsies (8-23 years), and 23 healthy controls (8-27 years). All underwent the Test of Non-verbal Intelligence, a motor-independent test, which excludes biased results due to motor impairment. Language lateralization was determined with functional MRI, lesion size with MRI-based volumetry, and hand motor impairment with the Jebson-Taylor Hand Function-Test. Results: Patients with epilepsies showed significantly impaired non-verbal intelligence [Md = 89.5, interquartile range (IQR) = 13.5] compared with controls (Md = 103, IQR = 17). In contrast, patients without epilepsies (Md = 97, IQR = 15.0) performed within the range of typically developing children. A multiple regression analysis revealed only epilepsy as a significant risk factor for impaired non-verbal functions. Conclusion: In patients with unilateral perinatal strokes without epilepsies, the neuroplastic potential of one healthy hemisphere is able to support the development of normal non-verbal cognitive abilities, regardless of lesion size, lesion side, or language lateralization. In contrast, epilepsy substantially reduces this neuroplastic potential; even seizure-free patients exhibit below-average non-verbal cognitive functions.

New insights from children with early focal brain injury: Lessons to be learned from examining STEM-related skills

The study of cognitive development in children with early brain injury reveals crucial information about the developing brain and its plasticity. However, information on long-term outcomes of these children, especially in domains relevant to science, technology, engineering, and math (STEM) remains limited. In the current review, our goal is to address the existing research on cognitive development of children with pre- or perinatal focal brain lesion (PL) as it relates to children's STEM-related skills and suggest future work that could shed further light on the developmental trajectories of children with PL. We argue that examining STEM-related development in children with PL will have broader implications for our understanding of the nature of the plasticity children with PL exhibit as well as address theoretical questions in the field regarding the foundation skills for STEM, including visuospatial and mathematical skills.

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.

Clock drawing in children with perinatal stroke

BACKGROUND

Children with perinatal stroke may show evidence of contralateral spatial neglect. The goal of this study was to determine whether the Clock Drawing Test commonly used in adults to identify neglect would be effective in detecting neglect in children with perinatal stroke.

METHODS

Thirty-eight individuals (age range 6-21 years) with left hemisphere or right hemisphere perinatal onset unilateral lesions and 179 age-matched controls were given a free-drawn Clock Drawing Test in a cross-sectional design. An adapted scoring system that evaluated right- and left-sided errors separately was developed as part of the investigation.

RESULTS

Children with right hemisphere lesions made a greater number of errors on both the right and left sides of the clock drawings in all age subgroups (6-8 years, 9-14 years, and 15-21 years) compared with controls. Children with right hemisphere lesions showed greater left and right errors in the younger groups compared with controls, with significantly poorer performance on the left at 6-8 years, suggestive of contralateral neglect. However, by ages 15-21 years, the right hemisphere lesion subjects no longer differed from controls.

CONCLUSIONS

Clock drawing can identify spatial neglect in children with early hemispheric damage. However, brain development is a dynamic process, and as children age, spatial neglect may no longer be evident. These findings demonstrate the limitations of predicting long-term outcome after perinatal stroke from early neurocognitive data. Children with perinatal stroke may require different neural pathways to accomplish specific skills or to overcome deficits, but ultimately they may have "typical" outcomes.

Determinants of cognitive outcomes of perinatal and childhood stroke: A review

Our understanding of cognitive and behavioral outcomes of perinatal and childhood stroke is rapidly evolving. A current understanding of cognitive outcomes following pediatric stroke can inform prognosis and direct interventions and our understanding of plasticity in the developing brain. However, our understanding of these outcomes has been hampered by the notable heterogeneity that exists amongst the pediatric stroke population, as the influences of various demographic, cognitive, neurological, etiological, and psychosocial variables preclude broad generalizations about outcomes in any one cognitive domain. We therefore aimed to conduct a detailed overview of the published literature regarding the effects of age at stroke, time since stroke, sex, etiology, lesion characteristics (i.e., location, laterality, volume), neurologic impairment, and seizures on cognitive outcomes following pediatric stroke. A key theme arising from this review is the importance of interactive effects among variables on cognitive outcomes following pediatric stroke. Interactions particularly of note include the following: (a) age at Stroke x Lesion Location; (b) Lesion Characteristics (i.e., volume, location) x Neurologic Impairment; (c) Lesion Volume x Time Since Stroke; (d) Sex x Lesion Laterality; and (e) Seizures x Time Since Stroke. Further, it appears that these relationships do not always apply uniformly across cognitive domains but, rather, are contingent upon the cognitive ability in question. Implications for future research directions are discussed.

Spatial analysis after perinatal stroke: patterns of neglect and exploration in extra-personal space

This study was conducted to determine whether school-aged children who had experienced a perinatal stroke demonstrate evidence of persistent spatial neglect, and if such neglect was specific to the visual domain or was more generalized. Two studies were carried out. In the first, 38 children with either left hemisphere (LH) or right hemisphere (RH) damage and 50 age-matched controls were given visual cancellation tasks varying in two factors: target stimuli and stimulus array. In the second study, tactile neglect was evaluated in 41 children with LH or RH damage and 72 age-matched controls using a blindfolded manual exploration task. On the visual cancellation task, LH subjects omitted more target stimuli on the right, but also on the left, compared with controls. Children with RH lesions also produced a larger number of omissions on both the left and right sides than controls, but with poorer performance on the left. On the manual exploration task, LH children required significantly longer times to locate the target on both sides of the board than did controls. RH children had significantly prolonged search times on the left side, but not on the right, compared with controls. In both tasks, LH subjects employed unsystematic search strategies more often than both control and RH children. The search strategy of RH children also tended to be erratic when compared to controls, but only in the random arrays of the visual cancellation tasks; structure of the target stimuli improved their organization. These results demonstrate that children with early LH brain damage display bilateral difficulties in visual and tactile modalities; a pattern that is in contrast to that seen in adults with LH damage. This may result from disorganized search strategies or other subtle spatial or attentional deficits. Results of performance of RH children suggests the presence of contralateral neglect in both the visual and tactile modalities; a finding that is similar to the neglect in adult stroke patients with RH lesions. The fact that deficits in spatial attention and organizational strategies are present after very early focal damage to either the LH or the RH broadens our understanding of the differences in functional lateralization between the immature and mature brain. These results also add to evidence for limitations to plasticity in the developing brain. Our findings may have therapeutic and rehabilitative implications for the management of children with early focal brain lesions.

Enhanced oscillatory activity in the hippocampal-prefrontal network is related to short-term memory function after early-life seizures

Neurological insults during development are associated with later impairments in learning and memory. Although remedial training can help restore cognitive function, the neural mechanisms of this recovery in memory systems are largely unknown. To examine this issue, we measured electrophysiological oscillatory activity in the hippocampus (both CA3 and CA1) and prefrontal cortex of adult rats that had experienced repeated seizures in the first weeks of life, while they were remedially trained on a delayed-nonmatch-to-sample memory task. Seizure-exposed rats showed initial difficulties learning the task but performed similarly to control rats after extra training. Whole-session analyses illustrated enhanced theta power in all three structures while seizure rats learned response tasks before the memory task. While performing the memory task, dynamic oscillation patterns revealed that prefrontal cortex theta power was increased among seizure-exposed rats. This enhancement appeared after the first memory-training steps using short delays and plateaued at the most difficult steps, which included both short and long delays. Further, seizure rats showed enhanced CA1-prefrontal cortex theta coherence in correct trials compared with incorrect trials when long delays were imposed, suggesting increased hippocampal-prefrontal cortex synchrony for the task in this group when memory demand was high. Seizure-exposed rats also showed heightened gamma power and coherence among all three structures during the trials. Our results demonstrate the first evidence of hippocampal-prefrontal enhancements following seizures in early development. Dynamic compensatory changes in this network and interconnected circuits may underpin cognitive rehabilitation following other neurological insults to higher cognitive systems.

Brain structure in prenatal stroke: quantitative magnetic resonance imaging (MRI) analysis

Neonatal stroke outcome studies demonstrate variable findings of either relatively spared intellectual function or persistent impairments. Volumetric measurement of the brain can provide more precise data on lesion-cognition outcomes. We studied 7 children with unilateral focal lesions from prenatal stroke. Whole-brain magnetic resonance imaging scans were analyzed to produce volumes of cortical gray matter, total white matter, cerebrospinal fluid, lesion, and lesion constricted fluid, and we ascertained the relationship of morphometric variables to intellectual and clinical outcome. Children with cystic encephalomalacia plus atrophy had poorer outcomes than children with atrophy or gliosis alone. These children also demonstrated the largest lesion size, smallest gray matter volume, and greatest proportion of hyperintense white matter in the affected hemisphere. Findings suggest that the type and size of the lesion, in addition to the integrity of white matter and residual cortex, may be better predictors of intellectual functioning than either of these indices alone.

Brain plasticity and recovery from early cortical injury

There is a general view that early brain damage leads to a far better outcome than damage later in life. Although there is a grain of truth to this idea, the reality is far more complex. We have identified a set of nine principles that underlie behavioral and anatomical changes after neonatal cortical injury as well as describing a variety of pre- and postnatal factors that modulate brain and behavioral plasticity after neonatal cortical lesions.

Visual cortical plasticity following unilateral sensorimotor cortical lesions in the neonatal rat

Previous work has shown that unilateral sensorimotor cortex (SMC) lesions in newborn rats resulted in an apparent shift of the motor cortex map in the spared hemisphere, particularly of the hindlimb cortex. In view of such findings, the present study was initiated to determine if the visual cortex located both ipsilateral and contralateral to neonatal SMC, or contralateral to occipital cortical (OC) lesions, would show similar remodeling. Visual evoked potentials (VEPs) were used to map the visual cortex electrophysiologically. The results show an expansion of the visual cortex, in both the contralateral and ipsilateral hemisphere, into normally motor cortical areas in adult animals that had sustained unilateral neonatal unilateral SMC lesions. In contrast, similar changes were not seen within the spared visual cortex after unilateral occipital cortical lesions, suggesting that the shift in the visual map was specifically in response to the SMC lesion and was not a generalized response to neonatal cortical damage. Histological analysis showed a functional expansion in the rostral boundary of visual cortex with no corresponding cytoarchitectural alterations.

Early brain lesions and face-processing development

Studies of functional plasticity after pre- or perinatal brain damage can tell us whether the neural substrate normally involved in the development of a given ability is specific and, if so, when it becomes functionally specified and unique. Development of face processing was investigated in 5- to 17-year-old children who had a unilateral brain injury in the pre-, peri-, or postnatal period. In Studies 1 and 2, patients with a posterior injury involving the temporal regions exhibited a face-processing deficit that was independent of their age at test time. Even though differences were observed between the two hemispheres in face processing during infancy as well as in adults in cases of normal development, no clear differences between right and left injury were observed here in face-processing deficit. Poor postlesional face-processing plasticity seems to contrast with results of several studies on speech development after early unilateral injury. If the difference in the time window for postlesional plasticity between these two areas of competency is confirmed, it would suggest that the two kinds of abilities rely on neural cells which are sensitive to different plasticity factors.

Attention function after childhood stroke

We investigated attentional outcome after childhood stroke and orthopedic diagnosis in medical controls. Twenty-nine children with focal stroke lesions and individually matched children with clubfoot or scoliosis were studied with standardized attention and neuroimaging assessments. Stroke lesions were quite varied in location and commonly involved regions implicated in Posner's model of attention networks. Children with stroke lesions performed significantly more poorly regarding attention function compared with controls. Performance on the Starry Night, a test demanding alerting and sensory-orienting but not executive attention function, was significantly associated with lesion size in the alerting and sensory-orienting networks but not the executive attention network. Furthermore, earlier age at lesion acquisition was significantly associated with poorer attention function even when lesion size was controlled. These findings support the theory of dissociable networks of attention and add to evidence from studies of children with diffuse and focal brain damage that early insults are associated with worse long-term outcomes in many domains of neuropsychological function. In addition, these results may provide clues towards the understanding of mechanisms underlying attention in children.

Functional MRI of global and local processing in children

Functional magnetic resonance imaging was used to examine developmental change in hemispheric biases for globally and locally directed analysis of hierarchical forms. In a previous reaction time (RT) study, which presented hierarchical stimuli to the visual hemifields, children 7 to 14 years of age demonstrated an emerging pattern of hemispheric differences. Initially children analyzed local elements more slowly, without a strongly lateralized advantage for local or global level processing. With age, children's development was marked by a left hemisphere advantage for local level processing that resembled an adult's and a trend toward a right hemisphere advantage for global. In the current study, 20 children 12 to 14 years old were imaged during attend-global and attend-local conditions to determine whether the developmental change in cognitive measures corresponded to a change in distribution of functional activation. Children formed two groups based on their RT performance, immature-bilateral (IB) or mature-lateralized (ML). The volume of task-related activation within lateral temporo-occipital regions of interest was compared for global and local conditions between the two groups. The IB children showed greater activation overall for local level processing, comparable activation across the two hemispheres for the global condition, and a trend of right greater than left hemisphere activation for local. In contrast, the ML children displayed right greater than left hemisphere activation during global analysis and the opposite during local processing. Importantly these patterns of functional activation mirror the profiles of RT performance. Together they demonstrate a shift from undifferentiated, bilateral processing toward hemispheric lateralization.

The impact of early unilateral brain injury on perceptual organization and visual memory

Studies of young children with early unilateral brain injury have suggested that while hemispheric differences in visuospatial processing appear to be present early in development, the young brain is better able to compensate for injury than when the injury occurs later, after networks have been established. The aim of this study was to determine if this pattern continues later in development when these children are given a challenging task: the Rey-Osterrieth Complex Figure. Experiment 1 included longitudinal data from ten children with early left hemisphere (LH) injury and nine children with early right hemisphere (RH) injury. Injury was presumed to be due to a prenatal or perinatal stroke. Compared with typically developing children, both groups were poorer in copying the figure. With development, these children produced reasonably accurate drawings but continued to use the most immature and piecemeal strategy. In Experiment 2, copy and immediate memory drawings from the 19 children with early unilateral brain injury were collected at a single age (11-14 years). Eight of the ten children with LH injury organized their memory reproductions around the core rectangle but included relatively few additional details. In contrast, only two of the nine children with RH injury organized their memory reproductions around the core rectangle and all but one produced the figure in a piecemeal manner. The results from both studies demonstrate the continuation of subtle deficits in visuospatial analysis with development but also the continued capacity for compensation.

Neural plasticity and cognitive development

It has been well documented that the effects of early occurring brain injury are often attenuated relative to later occurring injury. The traditional neuropsychological account of these observations is that, although the developing neural system normally proceeds along a well-specified maturational course, it has a transient capacity for plastic reorganization that can be recruited in the wake of injury. This characterization of early neural plasticity is limited and fails to capture the much more pervasive role of plasticity in development. This article examines the role of neural plasticity in development and learning. Data from both animal and human studies show that plasticity plays a central role in the normal development of neural systems allowing for adaptation and response to both exogenous and endogenous input. The capacity for reorganization and change is a critical feature of neural development, particularly in the postnatal period. Subtractive processes play a major role in the shaping and sculpting of neural organization. However, plasticity is neither transient nor unique to developing organisms. With development, neural systems stabilize and optimal patterns of functioning are achieved. Stabilization reduces, but does not eliminate, the capacity of the system to adapt. As the system stabilizes, plasticity becomes a less prominent feature of neural functioning, but it is not absent from the adult system. The implications of this broader view of plasticity for our understanding of development following early brain damage are discussed.

Developmental and lesion effects in brain activation during sentence comprehension and mental rotation

The development of neurocognitive networks was examined in 2 cognitive paradigms: auditory sentence comprehension and mental rotation of alphanumeric stimuli. Patterns of brain activation were measured with whole brain echoplanar functional magnetic resonance imaging at 3 Tesla in 5 adults (20-28 years old), 7 children (9-12 years old), and 6 pediatric patients (9-12 years old) with perinatal strokes or periventricular hemorrhages. Healthy children and adults activated similar neurocognitive networks, but there were developmental differences in the distribution of activity across these networks. In the sentence task, children showed more activation in the inferior visual area suggesting an imagery strategy rather than a linguistic strategy for sentence processing. Furthermore, consistent use of a sentence comprehension strategy, whether correct or incorrect as compared to chance performance, was associated with greater activation in the inferior frontal area (Broca's) in both children and pediatric patients. In the mental rotation task, healthy adults showed more activation in the superior parietal and middle frontal areas and less activation in the supramarginal gyrus, suggesting adults were primarily engaged in visual-spatial manipulation and less engaged in the recognition of noncanonical views of stimuli. The pediatric patients showed patterns of activation consistent with organization of cognitive processing into homologous areas of the contralateral hemisphere.

Drawing abilities in Williams syndrome: a case study

Children with Williams syndrome (WS) have been reported to exhibit an unusual cognitive profile characterized by marked preservation of linguistic abilities and poor visuospatial abilities against a backdrop of generalized mental retardation. Much of the data documenting this profile come from studies of older children and adults with WS. Very few studies have reported findings from the preschool and early school-age period. As a result, little is known about the early development of cognitive processes in children with WS. Capirci, Sabbadini, and Volterra (1996) reported data from a longitudinal case study of early language development in a young child with WS. This article presents the longitudinal profile of visuospatial abilities in this same child. Data on copying and free drawing collected over a period extending from late preschool to early school age are reported. It is clear from these data that this child does indeed exhibit deficits in visuospatial abilities. Her performance clearly improved with age, but deficits persist.

Functional organization of activation patterns in children: whole brain fMRI imaging during three different cognitive tasks

1. Patterns of brain activation were measured with whole brain echo-planar functional magnetic resonance imaging (fMRI) at 3.0 Tesla in healthy children (N = 6) and in one child with a left-hemisphere encephalomalacic lesion as sequellae from early stroke. 2. Three cognitive tasks were used: auditory sentence comprehension, verb generation to line drawings, and mental rotation of alphanumeric stimuli. 3. There was evidence for significant bilateral activation in all three cognitive tasks for the healthy children. Their patterns of activation were consistent with previous functional imaging studies with adults. 4. The child with a left-hemisphere stroke showed evidence of homologous organization in the non-damaged hemisphere.