Dyskinetic cerebral palsy. I. Clinical categories, associated neurological abnormalities and incidences

Dyskinetic Cerebral Palsy in Children: Clinical Perspectives on Common Comorbidities and Health-Related Quality of Life

BACKGROUND

The data on specific comorbidities in children with dyskinetic cerebral palsy (DCP) is limited. We evaluated the pattern of comorbidities and health related quality of life (HRQOL) in these children and compared them between etiological and motor impairment subgroups.

METHODOLOGY

This cross-sectional study was conducted over 18 months in children with DCP of both sex, and age between one and 14 years. Comorbidities were assessed using standardized scales such as gross motor functioning scale (GMFCS), developmental profile-3 (DP-3), developmental behaviour checklist, sleep behaviour questionnaire (SBQ), and caregiver questionnaire.

RESULTS

Sixty-five children with DCP were evaluated (hyperbilirubinemia n = 43, 66% and perinatal asphyxia n = 19, 29%). The majority of children were severely affected in gross motor functioning (level IV 29.2% and level V 53.8%). Epilepsy was seen in 21.5% of cases (19% in hyperbilirubinemia and 32% in asphyxia, p = 0.4). The mean age of onset of seizures was 15.4 + 20.6 months (range 2-72). Visual problems were seen in 54% of cases and included upgaze palsy, squint, refractive error, optic atrophy and cortical blindness. A significant proportion of children with hyperbilirubinemia had upgaze palsy as compared to those with perinatal asphyxia (70% vs. 32%, p 0.01). Rest of the visual problems were not significantly different between the two etiological subgroups. Drooling (87.6%), protein-energy malnutrition (66.6%), and reflux (57%) were the most common gastrointestinal problems in children with DCP. Children with DCP showed problems in social relating (33.8%), anxiety (26.2%), and self-absorbed behaviour (7.7%). However, there were no statistically significant differences between the etiological, motor impairment and age-based subgroups. Children with DCP had high scores on SBQ, suggesting sleep problems. Sleep scores were similar in the hyperbilirubinemia and perinatal asphyxia subgroups. Greater sleep problems were noted in children aged < 4y (70.6 + 10.1 vs. 56.5 + 11.3, p < 0.05 as compared to children above 4y of age) and severe motor impairments (68.2 + 11.3 vs. 57.2 + 13.1, p 0.008 as compared to mild-moderate motor impairment). Poor overall developmental scores were seen in 61.5% children and were significantly associated with GMFCS (p 0.04). The majority of children showed impairments in physical (58.5%), adaptive behaviour (58.5%), social-emotional (50.8%), cognitive (60%) and communication (52%) subscales of DP-3. Cognitive impairment was similar in the etiological (hyperbilirubinemia vs. perinatal asphyxia, p = 0.3), and motor impairment (mild-moderate vs. severe, p = 0.9) subgroups. HRQOL was significantly affected by motor impairment in positioning-transfer (p value 0.0001), and interaction-communication domains (p value 0.0001), however, there was no difference based on the etiology of hyperbilirubinemia and asphyxia.

CONCLUSION

Children with DCP demonstrate several comorbidities and impaired quality of life. These are similar in hyperbilirubinemia and perinatal asphyxia cohorts, expect for significant proportion of upgaze palsy in DCP secondary to hyperbilirubinemia. Younger children have more problematic behaviour and impaired sleep quality. Severe motor disability influences the developmental outcomes, cognition, sleep and HRQOL in children with DCP.

Prevalence of cerebral palsy and factors associated with cerebral palsy subtype: A population-based study in Belgium

AIM

To report on the prevalence, neuroimaging patterns, and function of children with cerebral palsy (CP) in Belgium for birth years 2007-2012, and identify distinctive risk indicators and differences in outcome between CP subtypes.

METHODS

Antenatal and perinatal/neonatal factors, motor and speech function, associated impairments, and neuroimaging patterns were extracted from the Belgian Cerebral Palsy Register. Prevalence was estimated per 1000 (overall, ante/perinatal, spastic, dyskinetic CP) or 10,000 (post-neonatal, ataxic CP) live births. Multinomial logistic regression analyses were performed to ascertain the effects of antenatal/perinatal/neonatal factors and neuroimaging patterns on the likelihood of dyskinetic or ataxic CP relative to spastic CP, and test the likelihood of the occurrence of impaired motor and speech function and associated impairments in dyskinetic or ataxic CP relative to spastic CP.

RESULTS

In total, 1127 children with CP were identified in Belgium. The birth prevalence of overall CP was 1.48 per 1000 live births. The likelihood of dyskinetic CP increases if the child was born to a mother aged ≥35 years, mechanically ventilated, and had predominant grey matter injury, while an increased likelihood of ataxic CP is associated with ≥2 previous deliveries. Children with dyskinetic and ataxic CP are more likely to function with impairments in motor, speech, and intellectual abilities.

CONCLUSION

Distinctive risk indicators and differences in outcome between CP subtypes were identified. These factors can be incorporated into clinical practice to facilitate early, accurate, and reliable classification of CP subtype, and may lead to individually tailored neonatal care and other (early) intervention options.

Attention deficit hyperactivity disorder is associated with (a)symmetric tonic neck primitive reflexes: a systematic review and meta-analysis

Introduction

Investigation on the association between attention deficit hyperactivity disorder (ADHD) and primary reflexes is in the initial stage, with considerable differences in the findings. This study evaluated the association between ADHD and primitive reflexes using systematic review and meta-analysis.

Methods

Data were obtained from PubMed, Cochrane Library, Web of Science, EBSCO (Medical Literature Analysis and Retrieval System Online, American Psychological Association Psyclnfo, and Education Resources Information Center), Embase, Scopus, and ProQuest. Articles were searched from the date of inception of the respective databases to January 01, 2023, and StataCorp Stata (version 15) was used for the analysis.

Results

Four articles with 229 samples were included in the meta-analysis. Results showed a significant positive and moderate correlation between ADHD and primitive reflexes, particularly asymmetric tonic neck reflex: summary r value = 0.48, 95% CI = 0.27-0.64; symmetric tonic neck reflex: summary r value = 0.39, 95% CI = 0.25-0.52. Overall, findings from the sub-group analysis indicate that the behavioral problem measuring tool (Conners' scale), sex, and primitive reflex test could significantly moderate the relationships between ADHD and ATNR and STNR primitive reflexes.

Conclusion

ADHD symptoms in children are closely related to the non-integration of (a)symmetric tonic neck primitive reflexes. Longitudinal or experimental studies should be conducted to reveal the causal relationship between ADHD and primitive reflexes in the future.

Children with dyskinetic cerebral palsy are severely affected as compared to bilateral spastic cerebral palsy

AIM

We aimed at describing clinical findings in children with dyskinetic as compared to bilateral spastic cerebral palsy (CP).

METHODS

Data were extracted from the Danish nationwide CP register. Participants were born in 1999-2007 and were 5-6 years at ascertainment.

RESULTS

The total number of CP cases was 1165 of which 92 had dyskinetic and 540 bilateral spastic CP. Prevalence of dyskinetic CP was 0.16 per 1000 live births. In participants with dyskinetic compared to bilateral spastic CP, there was more frequently an Apgar level less than five at five minutes (22.7% vs. 11.2%) and neonatal seizures (43.5% vs. 28.5%), but less respiratory deficiency, hyperbilirubinaemia and sepsis. Impairment based on gross motor function classification was more severe in dyskinetic CP (level III-V 90.0% vs. 66.0%). In dyskinetic CP, there was a high rate of reduced developmental quotient (68.1%), visual impairment (39.3%) and epilepsy (51.6%). Basal ganglia lesions were more prevalent in dyskinetic compared to bilateral spastic CP (27.7% vs. 12.8%).

CONCLUSION

Cases of dyskinetic CP had overlapping clinical features with cases of bilateral spastic CP, but differed significantly in several perinatal risk factors. The children with dyskinetic CP had experienced more peri- or neonatal adverse events, and neurodevelopmental impairment was severe.

A Model to Estimate the Optimal Layout for Assistive Communication Touchscreen Devices in Children With Dyskinetic Cerebral Palsy

Excess involuntary movements and slowness of movement in children with dyskinetic cerebral palsy often result in the inability to properly interact with augmentative and alternative communication (AAC) devices. This significantly limits communication. It is, therefore, essential to know how to adjust the device layout in order to maximize each child's rate of communication. The aim of this paper was to develop a mathematical model to estimate the information rate in children with dyskinetic cerebral palsy and to determine the optimal AAC layout for a touchscreen tablet that results in enhanced speed of communication. The model predicts information rate based on button size, number, spacing between buttons, and the probability of making an error or missing target buttons. Estimation of the information rate confirmed our hypothesis of lower channel capacity in children with dyskinetic cerebral palsy compared with age-matched healthy children. Information rate increased when the AAC layout was customized based on the optimal parameters predicted by the model. In conclusion, this paper quantifies the effect of motor impairments on communication with assistive communication devices and shows that communication performance can be improved by optimally matching the parameters of the AAC touchscreen device to the abilities of the child.

Clinical Management of Dystonia in Childhood

Dystonia is one of the most frequent movement disorders in childhood. It can impede normal motor development and cause significant motor disability. The diagnostic evaluation of childhood dystonia is challenging due to the phenotypic variability and heterogeneous etiologies. Evidence to guide the diagnostic evaluation and treatment is limited. Assessment is primarily directed by clinical history and distinctive examination findings. Neuroimaging is typically necessary to evaluate for acquired or complex inherited dystonias. A trial of levodopa can be both diagnostic and therapeutic in children with dopa-responsive dystonia. However, for the majority of children with early-onset dystonia, treatment is symptomatic with varying efficacy. There is a paucity of therapeutic trials for childhood dystonia and most treatment recommendations are consensus or expert opinion driven. This review summarizes the available evidence and guidelines on the diagnostic evaluation and pharmacological treatment of childhood-onset dystonia and provides practical frameworks to approach both issues based on best evidence.

The Dystonias

Dystonia is a difficult problem for both the clinician and the scientist. It is sufficiently common to be seen by almost all physicians, yet uncommon enough to prevent any physician from gaining broad experience in its diagnosis and treatment. Each case represents a difficult challenge even to the specialist. The basic scientist is faced with investigating a disorder that is without relevant animal models and which is so rare that obtaining suitable tissue for study is a major obstacle. Dystonia may be idiopathic, or associated with lesions from many sources, including a variety of rare diseases. If idiopathic, it may be genetically transmitted or sporadic. If genetically transmitted, it may be generalized or focal, with symptoms varying in different members of the same family. It may be refractory to treatment, or it may respond to any one of a number of individual drugs that have very different mechanisms of action. For idiopathic dystonias, no clear method of genetic transmission has been established and no consistent pathology identified.

Current and emerging strategies for treatment of childhood dystonia

Childhood dystonia is a movement disorder characterized by involuntary sustained or intermittent muscle contractions causing twisting and repetitive movements, abnormal postures, or both (Sanger et al, 2003). Dystonia is a devastating neurological condition that prevents the acquisition of normal motor skills during critical periods of development in children. Moreover, it is particularly debilitating in children when dystonia affects the upper extremities such that learning and consolidation of common daily motor actions are impeded. Thus, the treatment and rehabilitation of dystonia is a challenge that continuously requires exploration of novel interventions. This review will initially describe the underlying neurophysiological mechanisms of the motor impairments found in childhood dystonia followed by the clinical measurement tools that are available to document the presence and severity of symptoms. Finally, we will discuss the state-of-the-art of therapeutic options for childhood dystonia, with particular emphasis on emergent and innovative strategies.

Deep brain stimulation for the treatment of childhood dystonic cerebral palsy

OBJECT

Deep brain stimulation (DBS) for dystonic cerebral palsy (CP) has rarely been reported, and its efficacy, though modest when compared with that for primary dystonia, remains unclear, especially in the pediatric population. The authors present a small series of children with dystonic CP who underwent bilateral pallidal DBS, to evaluate the treatment's efficacy and safety in the pediatric dystonic CP population.

METHODS

The authors conducted a retrospective review of patients (under the age of 18 years) with dystonic CP who had undergone DBS of the bilateral globus pallidus internus between 2010 and 2012. Two of the authors independently assessed outcomes using the Barry-Albright Dystonia Scale (BADS) and the Burke-Fahn-Marsden Dystonia Rating Scale-movement (BFMDRS-M).

RESULTS

Five children were diagnosed with dystonic CP due to insults occurring before the age of 1 year. Mean age at surgery was 11 years (range 8-17 years), and the mean follow-up was 26.6 months (range 2-42 months). The mean target position was 20.6 mm lateral to the midcommissural point. The mean preoperative and postoperative BADS scores were 23.8 ± 4.9 (range 18.5-29.0) and 20.0 ± 5.5 (range 14.5-28.0), respectively, with a mean overall percent improvement of 16.0% (p = 0.14). The mean preoperative and postoperative BFMDRS-M scores were 73.3 ± 26.6 (range 38.5-102.0) and 52.4 ± 21.5 (range 34.0-80.0), respectively, with a mean overall percent improvement of 28.5% (p = 0.10). Those stimulated at least 23 months (4 patients) improved 18.3% (p = 0.14) on the BADS and 30.5% (p = 0.07) on the BFMDRS-M. The percentage improvement per body region yielded conflicting results between rating scales; however, BFMDRS-M scores for speech showed some of the greatest improvements. Two patients required hardware removal (1 complete system, 1 unilateral electrode) within 4 months after implantation because of infections that resolved with antibiotics.

CONCLUSIONS

All postoperative dystonia rating scale scores improved with pallidal stimulation, and the greatest improvements occurred in those stimulated the longest. The results were modest but comparable to findings in other similar series. Deep brain stimulation remains a viable treatment option for childhood dystonic CP, although young children may have an increased risk of infection. Of particular note, improvements in the BFMDRS-M subscores for speech were comparable to those for other muscle groups, a finding not previously reported.

Speed-accuracy testing on the Apple iPad provides a quantitative test of upper extremity motor performance in children with dystonia

The currently available scales for quantitative measurement of the severity of childhood dystonia require human observer ratings and provide poor granularity in the scores for individual limbs. We evaluated the use of new-generation high-quality touchscreens (an iPad) according with the Fitts law, which is a mathematical model that takes into account the relation between movement time and the task accuracy. We compared the abilities of healthy subjects and children with dystonia. The linear relation described by Fitts law held for all the groups. The movement time and the information transmitted were age and severity related. Our results provide evidence for the usability and validity of using Fitts law as a quantitative diagnostic tool in children with dystonia. Furthermore, testing on touchscreen tablets may help to guide the design of user interfaces to maximize the communication rate for children who depend upon assistive communication devices.

Animal models for drug discovery in dystonia

Dystonia is a neurological disorder characterized by involuntary twisting movements and unnatural postures. There are many different forms of dystonia, which affect over three million people worldwide. Effective treatments are available only for a minority of patients, so new treatments are sorely needed. Several animal species have been used to develop models for different forms of dystonia, each with differing strengths and weaknesses. This review outlines the strategies that have been used to exploit these models for drug discovery. Some have been used to dissect the pathogenesis of dystonia for the identification of molecular targets for intervention. Others have been used for the empirical identification of candidate drugs. Therefore, the animal models provide promising new tools for developing better treatments for dystonia.

Intrauterine growth restriction and cerebral palsy

Intrauterine growth restriction (IUGR) can be described as condition in which fetus fails to reach his potential growth. It is common diagnosis in obstetrics, and carries an increased risk of perinatal mortality and morbidity. Moreover, IUGR has lifelong implications on health, especially on neurological outcome. There is a need for additional neurological assessment during monitoring of fetal well-being, in order to better predict antenatally which fetuses are at risk for adverse neurological outcome. Studies have revealed that the behavior of the fetus reflects the maturational processes of the central nervous system (CNS). Hence, ultrasound investigation of the fetal behavior can give us insight into the integrity and functioning of the fetal CNS. Furthermore, investigations carried out using modern method, four-dimensional (4D) sonography, have produced invaluable details of fetal behavior and its development, opening the door to a better understanding of the prenatal functional development of the CNS. Based on previous observations and several years of investigation, our reaserch group has proposed a new scoring system for the assessment of fetal neurological status by 4D sonography named Kurjak antenatal neurodevelopmental test (KANET). The value of KANET in distinguishing fetal brain and neurodevelopmental alterations due to the early brain impairment in utero is yet to be assessed in large population studies. However, preliminary results are very encouraging.

Effects of intrathecal baclofen on daily care in children with secondary generalized dystonia: a pilot study

AIM

Treatment options for dystonic cerebral palsy (CP) are limited. Our aims were to determine whether intrathecal baclofen (ITB) improves daily care, decreases dystonia and decreases pain in patients with dystonic CP.

METHODS

Patients received randomized blinded treatment with ITB or placebo. Scores on problems of daily care were recorded and dystonia, pain and comfort were assessed.

RESULTS

Four patients (three males, average age 12 years 6 months) were included (all Gross Motor Function Classification System level V). During the trial period problem scores and dystonia scores decreased in all four patients.

CONCLUSION

In this pilot study we report positive functional effects of ITB trial treatment in four patients with dystonic CP. A randomized trial with a larger cohort is needed to verify these results.

Birth-related syndromes of athetosis and kernicterus

"Athetosis," from the Greek athetos, meaning "without fixed position," is a movement disorder first described by Hammond in 1871. The term described slow, irregular continual movements of the distal extremities. In 1983, Foley defined the athetoid syndrome as "a nonprogressive but evolving disorder due to damage to the basal ganglia of the full-term brain … [with] impairment of postural reflexes, arrhythmical involuntary movements, and dysarthria, [but] sparing … sensation, ocular movements and … intelligence." A decade later, "athetoid syndrome" was replaced by "dyskinetic cerebral palsy." Injury to basal ganglia by various mechanisms, including asphyxia, trauma, perinatal strokes, and kernicterus, is known to cause birth-related athetosis. Kernicterus originally described the neuropathology of bilirubin-induced brain injury, where the deep nuclei of the brain stain yellow. Kernicterus now describes the clinical features of chronic bilirubin encephalopathy, which include an extrapyramidal movement disorder, sensorineural hearing loss, impaired upward gaze, and dental enamel dysplasia. Aggressive treatment of perinatal hyperbilirubinemia has led to a decline in kernicterus so that, today, it is a rare cause of dyskinetic cerebral palsy. In this chapter, we provide a historic overview of athetosis and its formerly common cause, kernicterus. We relate earlier terminology to more recent definitions of impairments in dyskinetic cerebral palsy, including dystonia, chorea, and choreoathetosis.

Experimental therapeutics for dystonia

Dystonia is a neurological syndrome characterized by excessive involuntary muscle contractions leading to twisting movements and unnatural postures. It has many different clinical manifestations, and many different causes. More than 3 million people worldwide suffer from dystonia, yet there are few broadly effective treatments. In the past decade, progress in research has advanced our understanding of the pathogenesis of dystonia to a point where drug discovery efforts are now feasible. Several strategies can be used to develop novel therapeutics for dystonia. Existing therapies have only modest efficacy, but may be refined and improved to increase benefits while reducing side effects. Identifying rational targets for drug intervention based on the pathogenesis of dystonia is another strategy. The surge in both basic and clinical research discoveries has provided insights at all levels, including etiological, physiological and nosological, to enable such a targeted approach. The empirical approach to drug discovery, whereby compounds are identified using a nonmechanistic strategy, is complementary to the rational approach. With the recent development of multiple animal models of dystonia, it is now possible to develop assays and perform drug screens on vast numbers of compounds. This multifaceted approach to drug discovery in dystonia will likely provide lead compounds that can then be translated for clinical use.

Delayed-onset dystonia due to perinatal asphyxia: a prospective study

The objective of this work was to establish the existence and incidence of possible delayed-onset dystonia in a cohort of infants with diagnosed perinatal asphyxial hypoxic-ischemic encephalopathy (HIE). This prospective study comprised 103 survivors of perinatal asphyxial HIE, who were regularly followed and neurologically examined in the course of 7 to 13 years after birth (median 10 years). Neurological outcome at the end of the follow-up period was normal in 87 (84.5%) patients, while in 7 (6.8%) only mild neurological signs were detected (behavioral disturbances in 3, clumsiness in 2, and hypotonia in 1 patient). Severe cerebral palsy was diagnosed in nine patients (8.7%). Only one patient was diagnosed with possible delayed-onset segmental dystonia. At the age of 4 years he developed cervical dystonia with spread to one arm in the course of 1.5 years (segmental dystonia) and then stabilized. Other known causes of dystonia, including a DYT1 mutation, were excluded. Our preliminary data suggest that over the course of at least 7 years after birth, approximately 1% of infants who survived perinatal asphyxial HIE would develop delayed-onset dystonia.

Neurogenic bladder: etiology and assessment

A review of the various causes of neurologic impairment to the lower urinary tract in children was the aim of this presentation. The emphasis was on diagnosis, pathophysiology, and treatment that strive to maintain as normal a function as possible in order to achieve eventual urinary continence and health of the upper urinary tract. The latest principles based on the most up to date evidence are promulgated but with an eye towards historical prospective. The reader should gain an adequate understanding of various disorders that comprise this condition and feel comfortable with proposing options for management when faced with the responsibility of caring for an affected child.

Cerebral palsy in a total population of 4-11 year olds in southern Sweden. Prevalence and distribution according to different CP classification systems

BACKGROUND

The aim of this study was to investigate the prevalence of cerebral palsy (CP) as well as to characterize the CP population, its participation in a secondary prevention programme (CPUP) and to validate the CPUP database.

METHODS

The study population was born 1990-1997 and resident in Skåne/Blekinge on Jan 1st 2002. Multiple sources were used. Irrespective of earlier diagnoses, neuropaediatrician and other professional medical records were evaluated for all children at the child habilitation units. The CPUP database and diagnosis registers at hospital departments were searched for children with CP or psychomotor retardation, whose records were then evaluated. To enhance early prevention, CP/probable CP was searched for also in children below four years of age born 1998-2001.

RESULTS

The prevalence of CP was 2.4/1,000 (95% CI 2.1-2.6) in children 4-11 years of age born in Sweden, excluding post-neonatally acquired CP. Children born abroad had a higher prevalence of CP with more severe functional limitations. In the total population, the prevalence of CP was 2.7/1,000 (95% CI 2.4-3.0) and 48% were GMFCS-level I (the mildest limitation of gross motor function). One third of the children with CP, who were born or had moved into the area after a previous study in 1998, were not in the CPUP database. The subtype classification in the CPUP database was adjusted in the case of every fifth child aged 4-7 years not previously reviewed.

CONCLUSION

The prevalence of CP and the subtype distribution did not differ from that reported in other studies, although the proportion of mild CP tended to be higher. The availability of a second opinion about the classification of CP/CP subtypes is necessary in order to keep a CP register valid, as well as an active search for undiagnosed CP among children with other impairments.

Dyskinetic cerebral palsy: a population-based study of children born between 1991 and 1998

The aim of this study was to describe the epidemiology, aetiology, and clinical findings in dyskinetic cerebral palsy (CP)in a population-based follow-up study of children born between 1991 and 1998. Age range at ascertainment was 4 to 8 years and prevalence was 0.27 per 1000 live-births. Forty-eight children were examined (27 males, 21 females; mean age 9y, range 5-13y). Thirty-nine had dystonic CP and nine a choreo-athetotic subtype. Primitive reflexes were present in 43 children and spasticity in 33. Gross Motor Function Classification System levels were: Level IV, n= 10 and Level V, n= 28. The rate of learning disability (n= 35) and epilepsy (n= 30) increased with the severity of the motor disability. Thirty-eight children had anarthria. Peri- or neonatal adverse events had been present in 34 of 42 children born at >or=34 weeks' gestation. Motor impairment was most severe in this group. Placental abruption or uterine rupture had occurred in 8 participants and 19 of the 42 near-term/term children required assisted ventilation, compared with 1% and 12% respectively in other CP types. Neuroimaging in 39 children born at >or=34 weeks revealed isolated, late third trimester lesions in 24 and a combination of early and late third trimester lesions in seven. Dyskinetic CP is the dominant type of CP found in term-born, appropriate-for-gestational-age children with severe impairments who have frequently experienced adverse perinatal events.

Cerebral palsy and intrauterine growth

When birth weight for gestation is used as a surrogate for intrauterine growth, the prevalence of cerebral palsy varies continuously in a reversed J shape, with steep increases in the risk for infants lighter and heavier than the optimum size. Patterns of size-at-birth specific risk for cerebral palsy differ between male and female infants, as do the patterns for more severe versus milder cases. Although these excess risks with abnormal size at birth imply antenatal precursors, it is not clear whether or how intrauterine growth is involved in any of the suspected causal pathways resulting in cerebral palsy. The implication for clinicians is that serial measures of in utero growth may provide an important indicator of fetal health.

Toward a definition of childhood dystonia

PURPOSE OF REVIEW

The purpose of this review is to summarize recent progress toward providing a consistent, sensitive, specific, and useful definition of dystonia as it presents in childhood.

RECENT FINDINGS

An NIH-funded consensus group published a definition of childhood dystonia in January of 2003. Recent work has attempted to identify quantitative methods for diagnosis and measurement of childhood dystonia. Techniques include biomechanical, kinematic, and surface EMG measurements that show promise for providing specific and sensitive measures of childhood dystonia.

SUMMARY

The results of current research efforts will be useful for verifying and modifying definitions of dystonia to provide consistent and measurable terms for including children in research trials and selecting appropriate interventions for clinical treatment.

Late Measures of Brain Injury After Neonatal Hypoxia–Ischemia in Mice

BACKGROUND AND PURPOSE

This work was undertaken to determine to what degree long-term neurofunctional outcome of neonatal hypoxic-ischemic (HI) brain injury in mice correlates with anatomical extent of cerebral damage assessed by magnetic resonance imaging (MRI) and histopathology.

METHODS

On postnatal day 7, mice were subjected to HI. At 7 to 9 weeks after HI neurofunctional outcome was assessed by water-maze, rota-rod, and open-field test performance, followed by cerebral MRI and histopathology evaluation.

RESULTS

At 10 weeks after HI, MRI revealed ipsilateral brain atrophy alone or with porencephalic cyst formation and contralateral ventriculomegaly. Adult HI-affected mice, especially those that developed a porencephalic cyst, demonstrated significant neurofunctional deficit compared with age-matched naïve mice. HI-affected mice with ipsilateral cerebral atrophy but without porencephaly demonstrated no or an intermediate level of neurofunctional deficit. Neurobehavioral assessment of mice subjected to HI insult revealed a strong correlation between degree of brain injury and functional neurohandicap.

CONCLUSIONS

This is the first study to demonstrate that long-term neurofunctional outcome in mice after a neonatal HI correlates tightly with anatomical pattern/extent of cerebral damage, defined by MRI and histopathology.

Cerebral palsy and intrauterine growth in single births: European collaborative study

BACKGROUND

Cerebral palsy seems to be more common in term babies whose birthweight is low for their gestational age at delivery, but past analyses have been hampered by small datasets and Z-score calculation methods.

METHODS

We compared data from ten European registers for 4503 singleton children with cerebral palsy born between 1976 and 1990 with the number of births in each study population. Weight and gestation of these children were compared with reference standards for the normal spread of gestation and weight-for-gestational age at birth.

FINDINGS

Babies of 32-42 weeks' gestation with a birthweight for gestational age below the 10th percentile (using fetal growth standards) were 4-6 times more likely to have cerebral palsy than were children in a reference band between the 25th and 75th percentiles. In children with a weight above the 97th percentile, the increased risk was smaller (from 1.6 to 3.1), but still significant. Those with a birthweight about 1 SD above average always had the lowest risk of cerebral palsy. A similar pattern was seen in those with unilateral or bilateral spasticity, as in those with a dyskinetic or ataxic disability. In babies of less than 32 weeks' gestation, the relation between weight and risk was less clear.

INTERPRETATION

The risk of cerebral palsy, like the risk of perinatal death, is lowest in babies who are of above average weight-for-gestation at birth, but risk rises when weight is well above normal as well as when it is well below normal. Whether deviant growth is the cause or a consequence of the disability remains to be determined.

Pathophysiology of pediatric movement disorders

Pediatric movement disorders constitute a relatively small cluster of symptoms that can be associated with many different underlying diseases. To provide effective treatment, it is essential to understand the relationship between etiology and clinical expression. This article reviews the recent literature on several common pediatric movement disorders, including spasticity, dystonia, chorea, myoclonus, bradykinesia, and tics, and it discusses current models of physiology that may help link the cellular pathology of specific diseases to the expression of clinical symptoms.

Genetic factors in athetoid cerebral palsy

Within the cerebral palsy syndromes, athetosis is most commonly causally associated with serious perinatal complications. Genetic factors are thought to play a lesser role, although the risk of recurrence in siblings has been suggested to be as high as 10%. We have conducted a clinical study of 22 subjects with a diagnosis of athetoid cerebral palsy and a review of the literature aiming to identify instances of familial recurrence of athetoid cerebral palsy. The birth history, family history, and previous investigations of subjects with athetoid cerebral palsy were studied and subjects were clinically examined for evidence of an underlying genetic etiology. Factors suggesting a genetic cause were specifically sought, such as advanced paternal age, progression of symptoms, and associated congenital abnormalities. No subjects in the study group had similarly affected relatives, and additional features suggesting a genetic cause were not observed. A literature search identified 16 instances of familial recurrence of athetoid cerebral palsy. Familial cases were typically associated with significant spasticity, microcephaly, intellectual disability, seizures, and a lack of history of birth asphyxia, and most could be explained by either autosomal-recessive or X-linked-recessive inheritance. The genetic contribution to athetoid cerebral palsy is small, with an overall risk of recurrence in siblings of about 1%. This risk is lower than previously suggested in the literature.

Bilateral thalamic lesions in a newborn with intrauterine asphyxia after maternal cardiac arrest--a case report with literature review

Hypoxic-ischemic brain damage in preterm and term infants is one major cause of neonatal neurologic morbidity. Depending on the gestational age and the extent of hypoxia, different pathologic findings have been observed. Hypoxic-ischemic lesion of the thalamus is the least common form of cerebral injury. Although long-term outcome with spastic or extrapyramidal cerebral palsy is known, clinical features in the neonatal period are not well described. We report an infant with bilateral hypoxic-ischemic thalamic lesions after maternal cardiac arrest at 28 weeks of gestation. Clinical features and diagnostic results of our patient are compared to information given in the literature to define the clinical entity of hypoxic-ischemic thalamic lesions in neonates better.

Epilepsy in very preterm infants: neonatal cranial ultrasound reveals a high-risk subcategory

The aim of this study was to investigate the association between epilepsy and perinatal brain injury in a cohort of 610 infants born preterm at <33 weeks' gestation. The prevalence of epilepsy in this cohort was 4.3% as determined by a postal questionnaire survey. Most children with epilepsy (16 of 24) had high-risk cranial ultrasound lesions including haemorrhagic parenchymal infarction (HPI), posthaemorrhagic hydrocephalus, and cystic periventricular leukomalacia (PVL). Of all the children in our cohort with high-risk brain lesions, those with epilepsy were more likely to have HPI and significantly less likely to have cystic PVL, although it is possible that PVL was not noticed in some cases. Children with epilepsy and high-risk cranial ultrasound lesions also showed more cognitive impairment than children with high-risk lesions but no epilepsy, which suggested more cortical grey-matter damage. We suggest that brain injury has occurred outside the confines of the periventricular white matter in this group of preterm infants with epilepsy.

Evolution of dopamine receptors in the rat after neonatal hypoxia-ischemia: autoradiographic studies

The aim of this work was to follow the evolution of striatal dopamine D1 and D2 receptors after hypoxic-ischemic (H/I) insult in immature rats. SPET imaging of these receptors could be used as an index to assess brain dysfunctions after perinatal H/I without change in cerebral blood flow or neuronal loss. We submitted 1-week-old rat pups to unilateral ligation of the left carotid artery plus 2h exposure to 8% O2. After recovery periods of 1, 2 or 9 weeks, ex vivo and in vitro autoradiographic studies of dopamine receptors were performed on normal appearing brains using specific ligands usable in human SPET imaging. Striatal dopamine D2 receptors tended to decrease bilaterally after one week's recovery. The decrease then reached 40% at 3 weeks of age and at 10 weeks of age the level of receptors had returned to normal values. By contrast, no change in dopamine D1 receptors was seen, whatever the age studied. In conclusion, changes in dopamine D2 receptors could be a valuable index for SPET imaging to evaluate H/I brain damage in the absence of anatomical lesions.

Neuropathophysiology of movement disorders in cerebral palsy

Recent developments in understanding the pathophysiology of disordered motor control in cerebral palsy are reviewed. In spastic cerebral palsy, evidence for abnormal segmental as well as supraspinal control of motor neuron output exists. Impaired Ia inhibition of antagonist muscles has been suggested but recently contested. Evidence also supports the role of decreased presynaptic inhibition of Ia afferents and decreased nonreciprocal Ib inhibition. Furthermore, early cerebral injury results in reorganization of supraspinal (corticospinal) inputs to motor neuron pools. In extrapyramidal cerebral palsy, injury of basal ganglia or thalamus has been demonstrated. A scheme for understanding the neurochemical circuitry of the extrapyramidal system is discussed. Animal models and certain specific human diseases provide examples of how this circuitry may be disturbed, thereby resulting in an imbalance between the direct and indirect striatal output systems and in impaired motor control. Future studies employing postmortem neurochemical analysis, functional magnetic resonance imaging, and positron emission tomographic scanning may foster progress in this area.

Oral pharmacotherapy for the movement disorders of cerebral palsy

Movement disorders are a well-recognized feature of some patients with cerebral palsy and often require treatment. However, treatments have been symptomatic and empiric, and there have been few pharmacologic studies. The major movement disorders in cerebral palsy are dystonia and the hyperkinesias choreoathetosis and myoclonus. They may occur in combination, often accompanied by spasticity and sometimes by epilepsy. Some drugs are useful treatments for all of these problems, but others may improve one while worsening another. Pitfalls in management include not diagnosing metabolic/degenerative disorders, which may mimic cerebral palsy, or not recognizing reversible complications of cerebral palsy, which may exacerbate symptoms. This review attempts to summarize empiric drug use and recommendations for therapy, drug studies in extrapyramidal cerebral palsy, and prospects for new drugs or models for the problem. Many new pharmacologic agents are available for study in cerebral palsy. Better methods of detecting basal ganglia injury after perinatal injury in asymptomatic infants may allow early intervention in the biologic process of recovery and adaptation.

The temporal evolution of striatal dopamine receptor binding and mRNA expression following hypoxia-ischemia in the neonatal rat

Neonatal hypoxic-ischemic (HI) brain injury in the rat alters dopamine receptors. To determine whether such changes are permanent, dopamine receptors and corresponding mRNA were examined at various time points after neonatal HI using receptor autoradiography and in situ hybridization. Rat pups underwent ligation of the left common carotid artery followed by hypoxic exposure (8.5% O2 for 3 h). Controls underwent sham surgery alone. Animals surviving for 2-80 days following HI were studied. Striatal D1 receptors (labeled by [3H]SCH23390) were reduced as early as 2 days following HI, remained depressed for 21 days, but recovered to control levels by young adulthood (3 months of age). D2 receptors (labeled by [125I] iodosulpride) did not decline until 10 days after HI, and remained uniformly depressed throughout the caudate-putamen thereafter. Changes in D1 receptor mRNA transcripts closely paralleled alterations in receptors: early reductions in D1 mRNA signal recovered by young adulthood. D2 mRNA exhibited a unique temporal profile with an early decrease (2 days following HI), and prompt, persistent recovery. Dopamine receptors and transcripts are differentially affected by HI injury early in development. Whereas D1 receptor expression recovers from neonatal HI injury, D2 receptors remain permanently affected despite the presence of normal levels of D2 receptor transcripts. A persistent, post-transcriptional effect of HI on D2 receptor expression is suggested.

Augmented pharmacologic stimulation of striatal acetylcholine release following developmental hypoxic-ischemic injury

We have previously shown that developmental hypoxic-ischemic injury in a unilateral rodent model leads to an increase in both morphologic and biochemical indices of striatal cholinergic neurons. To investigate the functional significance these changes, we have used the in vivo microdialysis technique to examine the regulation of striatal acetylcholine release in awake, adult rats following postnatal hypoxic-ischemic injury. We have found that injury does not alter basal release or acetylcholine, but it results in a marked augmentation in the increase of acetylcholine release normally observed after infusion of atropine or pirenzepine.

Nerve growth factor protects the neonatal brain against hypoxic-ischemic injury

Nerve growth factor (NGF) has been shown to protect specific neurons that express its signaling receptor, trkA, from a variety of insults. There are some data, in particular in the developing brain, indicating that NGF has neuroprotective actions that extend beyond cells expressing trkA. In this study, we asked whether NGF would protect against brain injury in a neonatal model of hypoxia-ischemia. Postnatal day (PD) 7 rat pups received a right carotid ligation and were then exposed to hypoxic conditions. Prior to carotid ligation and 48 hours later, pups received an intracerebroventricular injection of NGF or denatured NGF dissolved in vehicle or vehicle alone. Brains were then assessed at PD21. In vehicle- and denatured NGF-treated animals, there was significant damage (30-40% volume loss) to both the striatum and cortex ipsilateral to the carotid ligation. In contrast, little damage (10% volume loss) was observed in most NGF-treated animals. NGF injection studies revealed that NGF stimulated tyrosine phosphorylation of trkA in multiple brain regions. These results show that NGF appears globally neuroprotective to the developing brain in a neonatal model of hypoxia-ischemia and that there may be novel mechanisms in vivo through which NGF exerts its protective actions.

Apoptosis in substantia nigra following developmental hypoxic-ischemic injury

We have previously observed that either hypoxic-ischemic or excitotoxic striatal injury during development is associated with a reduction in the adult number of dopaminergic neurons in the substantia nigra. This decrease occurs in the presence of preserved striatal dopaminergic markers and in the absence of direct nigral injury. We have also observed that natural cell death, with the morphology of apoptosis, occurs in the substantia nigra, and that there is an induced apoptotic cell death event following early striatal excitotoxic injury. We now report that forebrain hypoxic-ischemic injury is also associated with an induced cell death event in the substantia nigra, with both morphological and histochemical features of apoptosis. Induced apoptotic cell death occurs in immunohistochemically defined dopaminergic neurons. While the mechanisms for this induced cell death are not yet known, in the case of the pars compacta it may be related to the loss of normal striatal target-derived developmental support. Since dopaminergic neurons are postmitotic at the time of the injury, we conclude that this induced cell death is responsible for the diminished adult number of dopaminergic neurons. We also conclude that hypoxic-ischemic injury to the developing brain in general causes not only direct, necrotic injury to vulnerable regions, but also induced apoptotic death at remote sites. The significance of this finding is that apoptosis is a distinct death mechanism, with unique regulatory pathways, which can potentially be modified by approaches different from those which might influence cell death in regions of direct injury. In view of the present finding that apoptosis can occur in the setting of hypoxic-ischemic injury, and our previous work demonstrating its occurrence following excitotoxic injury, it seems likely that it may occur following other forms of injury to the immature brain in which excitotoxic injury plays a role, such as seizures, head trauma and hypoglycemia.

Locomotion patterns in cerebral palsy syndromes

Locomotion patterns were studied in 160 children with cerebral palsy. Ten patterns were distinguished, which were typical of the type of impairment: (1) crawling--mildly impaired children who will achieve independent walking; (2) creeping and crawling--diplegic children with moderate motor impairment; (3) creeping, never leading to independent walking--children with severe diplegia or tetraplegia; (4) bottom shuffling--children with hemiplegia and ataxia and minimal or mild motor impairment; (5) bunny-hopping--dyskinetic children with marked motor impairment but generally not mentally retarded; (6) rolling--severely diplegic and dyskinetic children; (7) other forms of locomotion, such as bridging or grub-type creeping, rare and typical of children with ataxic elements; (8) just walk--children with hemiplegia, diplegia, ataxic diplegia or ataxia, generally in cases of mild motor impairment but mental retardation; (9) just walk with aids--children with severe diplegia; and (10) no mobility. The locomotion pattern, age at onset and even manner of execution all influenced prognosis for walking. Severe deformity affected the choice of locomotion pattern. Though physiotherapy probably would not greatly influence the adoption of a particular locomotion pattern, early intervention might help prevent deformities.

Effect of neonatal hypoxia-ischemia on nigro-striatal dopamine receptors and on striatal neuropeptide Y, dynorphin A and substance P concentrations in rats

Perinatal hypoxic-ischemic brain injury was induced in 7- to 8-day-old rats by ligating the left carotid artery with subsequent exposure to 9% oxygen atmosphere for 2.5 h. The animals were killed 7 days later and grouped according to the degree of brain injury sustained after hypoxia-ischemia. Total protein content measured in striatum ipsilateral to the ligation, and dissected from brains showing extensive damage, was reduced to 64% of contralateral tissue. The protein content was not altered in other groups including control animals exposed to air and in sham-operated animals exposed to hypoxic conditions. The concentration of (pg/mg protein) and total (pg/striatum) striatal dynorphin A-like immunoreactivity (DLI) from brains with extensive damage were increased to 481% and 285% of the contralateral side, respectively. Hypoxia-ischemia increased striatal neuropeptide Y-like immunoreactivity (NPYLI) concentration from brains with extensive damage to 157% of contralateral side, but when the results were expressed as total NPYLI content per striatum, NPYLI content in striatum with extensive damage remained unaltered. Substance P-like immunoreactivity (SPLI) concentration and total content per striatum from brains with extensive damage were reduced to 66% and 43% of the contralateral side, respectively. D1 and D2 receptor density in animals killed 10 days after injury was reduced by 24% and 22% of control, respectively, in striatum from brains with extensive damage. These results indicate complex changes in brain neuropeptides following neonatal hypoxia-ischemia. Damage in the substance P system could have functional effects on dopaminergic transmission while the increase in NPYLI and in DLI concentrations may respectively reflect the relative preservation from neuronal damage and possibly an increase in neuropeptide synthesis or decrease in release. The decrease in SPLI concentration and the increase DLI concentration induced by hypoxia-ischemia suggests that these peptides may be present in separate neurons.

Motor function of infants with athetoid cerebral palsy

The motor function of 35 children with athetoid cerebral palsy was examined retrospectively using videotape recordings made at five to eight months of age. Many infants showed asymmetric tonic neck, Moro and Galant reflexes. Movements shown to be difficult included: keeping a symmetric supine posture, isolated movements of the hips and knees, forward extension of the upper extremity, extension of neck and trunk in the prone position and in ventral suspension, flexion of the neck in the traction response, and weight support by the upper extremities. Asymmetric or excessive opening of the mouth was present in all infants. The grade of difficulty for each posture and movement might reflect subsequent motor disability at three years of age.

Parental age, genetic mutation, and cerebral palsy

Parental age and birth order were studied in 251 patients with cerebral palsy. No parental age or birth order effects were observed in spastic quadriplegia or diplegia, but a paternal age effect was detected in those with athetoid/dystonic cerebral palsy and congenital hemiplegia. These observations indicate that some cases of athetoid/dystonic or hemiplegic cerebral palsy might arise by fresh dominant genetic mutation.

Dyskinetic and dystonic cerebral palsy and birth

Two hundred and nineteen cases of the dyskinetic and dystonic forms of cerebral palsy which were seen in the course of three decades at a single clinic have been analysed. Fifty-seven patients had kernicterus. In the remaining 162, 71% of whom were born at term, birthweight was below the expected mean in two-thirds. There was no relationship between birth weight, or abnormal birth, or asphyxia, and the ultimate clinical severity of the children. We conclude that abnormal birth and asphyxia are not direct causes of the cerebral damage, but are expressions of a pre-existing condition resulting in susceptibility to the stress of birth, whether it is normal or abnormal.

Effect of unilateral perinatal hypoxic-ischemic brain injury in the rat on striatal muscarinic cholinergic receptors and high-affinity choline uptake sites: a quantitative autoradiographic study

The binding characteristics and distribution of M1 and M2 muscarinic cholinergic receptors and high-affinity choline uptake sites were studied in the striatum of the rat at 3-4 and 9-12 weeks of age after exposure to unilateral perinatal hypoxic-ischemic brain injury. High-affinity choline uptake sites were labeled with [3H]hemicholinium-3, M1 receptors with [3H]pirenzepine, and M2 receptors with [3H]AF-DX 116. Saturation experiments revealed a significant decrease in the maximal binding capacity (Bmax) for [3H]pirenzepine-labeled M1 receptors in the lesioned caudate/putamen complex in immature rats with moderate brain injury, in comparison with controls. In contrast, the Bmax value for [3H]hemicholinium-3-labeled high-affinity choline uptake sites was significantly increased. No changes in dissociation constants (KD) were observed. These changes were most pronounced in the dorsolateral region of striatum. Striatal regional distribution of [3H]AF-DX 116 was not affected. In mature rats, binding of [3H]pirenzepine returned to control values, whereas [3H]hemicholinium binding showed a persistent increase (23%). The increase in [3H]hemicholinium-3 binding, as a specific marker of cholinergic nerve terminals, is consistent with our prior morphologic studies demonstrating relative preservation of cholinergic neurons and neuropil, and supports the concept that striatal cholinergic systems are resistant to hypoxic-ischemic injury.

Effect of unilateral perinatal hypoxic-ischemic brain injury in the rat on dopamine D1 and D2 receptors and uptake sites: a quantitative autoradiographic study

The effect of a unilateral perinatal hypoxic-ischemic brain injury on dopamine D1 and D2 receptors and uptake sites was investigated in rats by using in vitro quantitative binding autoradiography, 2-3 weeks after the insult. We observed significant decreases in the Bmax and KD for [3H]SCH 23390-labeled D1 and in the Bmax for [3H]spiperone-labeled D2 receptors in the lesioned caudate-putamen in rats with moderate brain injury (visible loss in hemispheric volume ipsilateral to the injury) compared with the nonlesioned contralateral caudate-putamen or with control rats. Changes in [3H]SCH 23390 and [3H]spiperone binding predominated in the dorsolateral part of the lesioned caudate-putamen. Pronounced reduction in [3H]SCH 23390 binding was also observed in the substantia nigra pars reticulata on the side of the lesion. In contrast, we did not observe any significant change in Bmax or KD for [3H]mazindol-labeled dopamine uptake sites. Similarly, no significant changes in the levels of dopamine or its metabolites were found on the side of the lesion. The observed reductions in striatal dopamine D1 and D2 receptors are a reflection of striatal cell loss induced by the hypoxic-ischemic injury. The absence of changes in [3H]mazindol binding or dopamine levels in the lesioned caudate-putamen indicates that the dopaminergic presynaptic structures are preserved.

Magnetic resonance imaging in athetotic cerebral palsied children

The magnetic resonance findings in 22 children with athetotic cerebral palsy were studied. Sixteen had perinatal asphyxia, two had neonatal jaundice, and four had no association with predisposing conditions. In six of the children, symmetrical high intensity areas were found in both the thalamus and putamen in T2-weighted images. In five children they were seen only in the thalamus, and in another one only in the putamen. In six children, symmetrical periventricular high intensity areas were seen. In seven of the subjects, no abnormal magnetic resonance findings were seen. Magnetic resonance lesions, possibly caused by asphyxia, were found in the basal ganglia, thalamus and/or cerebral white matter in 14 of 16 children. Three children with lesions only in the cerebral white matter had mild motor abnormality, and six children with lesions in both the thalamus and putamen did not have mild abnormality.

Unilateral hypoxic-ischemic injury in neonatal rat results in a persistent increase in the density of striatal tyrosine hydroxylase immunoperoxidase staining

Little is known of the alterations in the neurochemical anatomy of the striatum following neonatal hypoxic-ischemic injury. In an experimental model in rodent, it has been shown that striatal biochemical markers of dopaminergic systems appear to be relatively spared. We sought to define the morphologic correlates of this finding by staining striatal tyrosine hydroxylase (TH)-positive fibers with the immunoperoxidase technique. Since this model is unilateral, it is possible to examine relative changes in the density of TH-positive staining of the striatum at the population level within the same section. We find that in immature animals (3-4 weeks) there is an increase in the relative density of striatal TH-positive staining on the injured side. There is also an increase in the relative density of staining in the nucleus accumbens, in the absence of shrinkage of that nucleus. There is no relationship between the degree of density increase in the striatum, and its degree of shrinkage. This increase in relative density is a persistent change, as it is also observed in adult rats (9-12 weeks). While the functional significance of these findings are unknown, they are compatible with a relative increase in the dopaminergic innervation of the hypoxia-ischemia injured striatum.