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Biomedical subjects

O van Nieuwenhuizen

Publications and source records attributed to O van Nieuwenhuizen.

At least 19 recordsLinked to original sources
PubMed2006

[Intracranial EEG monitoring for epilepsy surgery using electrode grids--results in the first 22 Dutch patients].

OBJECTIVE: Description of initial experiences with subdural electrode grids in patients with refractory focal epilepsy as additional diagnostic tool for epilepsy surgery. Using these electrodes, the attacks were recorded during a number of days and the cerebral cortex was electrically stimulated in order to map the functional areas. DESIGN: Retrospective. METHOD: Data were collected from patients in whom subdural electrode grids had been placed between 1 September 1999 and 31 August 2004. All patients underwent a neurological examination and a neuropsychological test before the implantation. At the follow-up examination, the results with regard to function and the frequency of attacks were noted, as well as the complications. RESULTS: Electrodes were placed in 22 patients: 9 women and 13 men with an average age of 27 years (range: 5-42). The implantation lasted for an average of 7 days (range: 3-10). In 4 patients, increased seizures during implantation required intravenous anticonvulsant treatment. Severe but transitory complications were seen in 4 patients (meningitis, subdural haematoma and ischaemia). 19 patients underwent a therapeutic resection. A postoperative decline in language skills was noted in 1 patient, while another 2 scored poorer in verbal tests. A permanent decline in sensorimotor function was seen in 1 patient, but this had been foreseen. Of the 16 operated patients with a duration of follow-up of at least 1 year, so were (practically) free of attacks, and another 3 patients had significantly fewer attacks. CONCLUSION: Registration with intracranial electrodes makes it possible to treat epileptic patients surgically by excision of brain tissue near critical areas. Such intensive monitoring is, however, not without risk and this must be weighed against the potential benefits.

Adolescent↗
PubMed2005

Propofol and thiopental for refractory status epilepticus in children.

To assess safety and efficacy of propofol and thiopental for refractory status epilepticus (RSE) in children, the authors reviewed 34 episodes of RSE. Thiopental was effective in most patients, but there were serious side effects. Propofol was used according to a strict protocol. It was effective in most patients, so that thiopental was not needed. Side effects were infrequent, of minor severity, and fully reversible. The authors suggest the use of propofol before thiopental.

Anticonvulsants↗
PubMed2005

Clinical presentation, associated disorders and aetiological moments in Cerebral Palsy: a Dutch population-based study.

PURPOSE: Cerebral Palsy (CP) contains varying clinical presentations, associated disorders and aetiological moments. Quantitative data and trends on these aspects were lacking in The Netherlands. METHOD: Within a population-based study on prevalence, presentation and functioning of Dutch children with CP born in the years 1977-1988, individual history taking, examination and medical file checking was done by experienced clinicians. Clinical subtypes, motor disability, important co-morbidity (mental retardation, visual disability and epilepsy) were recorded, aetiological moments identified if possible. By comparing the four most recent years with the earlier years possible trends were studied. RESULTS: A quarter of children beforehand recorded as CP did not meet inclusion criteria after individual examination. Spastic subtypes accounted for over 90% of all CP cases: bilateral spastic cerebral palsy as a group are the majority although spastic hemiplegia is percentage-wise the largest individual clinical subtype. Epilepsy and mental retardation are common. Clinical patterns and associated disorders remained rather constant comparing earlier to more recent birth years. CONCLUSIONS: An early diagnosis of CP may be challenged. General clinical patterns remained rather constant in following years, as did most studied items. Even if this study revealed a prevalence rise, no aspect stood out as a possible explanation for this prevalence rise. Comparable studies performed elsewhere showed similar findings.

Adolescent↗
PubMed2005

Epilepsy surgery does not harm motor performance of children and adolescents.

The impact of epilepsy surgery on motor performance, activities of daily life (ADL) and caregiver assistance was assessed in 37 children (age range 0.1-15.4 years) with pharmacologically untreatable epilepsy, 17 of whom were also diagnosed as having spasticity of cerebral origin. All patients underwent epilepsy surgery between 1996 and 2001 at the Wilhelmina University Children's Hospital and were assessed using a standard protocol at fixed intervals: before surgery and 6 months, 1 year and 2 years after surgery. The type of surgery was hemispherectomy (n = 14) and temporal (n = 14), frontal (n = 4), parietal (n = 2) and central (n = 2) resection. One child underwent callosotomy. Engel's classification was used to determine seizure outcome. Impairments were measured in terms of muscle strength, range of motion and muscle tone. Motor performance of infants and children without spasticity was measured using the Movement Assessment Battery for Children (M-ABC). The Gross Motor Function Measure (GMFM-88) was used in children with spasticity, the severity of motor disability in this group being determined by means of the Gross Motor Function Classification System (GMFCS). Daily activities and caregiver's assistance were measured in all children using the Pediatric Evaluation of Disability Inventory (PEDI). Twenty-four months after surgery 74% of the children could be classified as Engel class 1, indicating a significant seizure reduction. Impairments revealed some decrease in muscle strength and range of motion in the group with spasticity. Scores improved statistically significantly at group level on M-ABC and GMFM (P < 0.05). Improvement in activities of daily life and caregiver's assistance could not be measured in children without spasticity because of the ceiling effect of the PEDI, but children with spasticity improved significantly with respect to these parameters (PEDI) (P < 0.05). Hence, epilepsy surgery does not harm motor performance in children with or without spasticity.

Activities of Daily Living↗
PubMed2005

Thrombin-stimulated glutamate uptake in human platelets is predominantly mediated by the glial glutamate transporter EAAT2.

Glutamate toxicity has been implicated in the pathogenesis of various neurological diseases. Glial glutamate transporters play a key role in the regulation of extracellular glutamate levels in the brain by removing glutamate from the extracellular fluid. Since human blood platelets possess an active glutamate uptake system, they have been used as a peripheral model of glutamate transport in the central nervous system (CNS). The present study is aimed at identifying the glutamate transporter on blood platelets, and to asses the influence of platelet activation on glutamate uptake. Platelets from healthy donors showed Na+-dependent glutamate uptake (Km, 3.5+/-0.9 microM; Vmax, 2.8+/-0.2 pmol glutamate/75 x 10(6)platelets/30 min), which could be blocked dose-dependently by the EAAT specific inhibitors DL-threo-E-benzyloxyaspartate (TBOA), L-trans-pyrrolidine-2,4-dicarboxylic acid (tPDC) and high concentrations of the EAAT2 inhibitor dihydrokainate (DHK). Analysis of platelet homogenates on Western blots showed EAAT2 as the predominant glutamate transporter. Platelet activation by thrombin caused an increase in glutamate uptake, which could be inhibited by TBOA and the EAAT2 inhibitor DHK. Kinetic analysis showed recruitment of new transporters to the membrane. Indeed, Western blot analysis of subcellular fractions revealed that alpha-granules, which fuse with the membrane upon thrombin stimulation, contained significant EAAT2 immunoreactivity. Inhibition of the second messengers involved in alpha-granule secretion (protein kinase C, phosphatidylinositol-3-kinase) inhibited thrombin-stimulated uptake, but not basal uptake. These data show that the glial EAAT2 is the predominant glutamate transporter on blood platelets and suggest, that thrombin increases glutamate uptake capacity by recruiting new transporters (EAAT2) from alpha-granules.

Adenosine Diphosphate↗
PubMed2005

Role of visual dysfunction in postural control in children with cerebral palsy.

INTRODUCTION: Deficient postural control is one of the key problems in cerebral palsy (CP). Little, however, is known about the specific nature of postural problems of children with CP, nor of the relation between abnormal posture and dysfunction of the visual system. AIM OF THE STUDY: To provide additional information on the association of abnormalities in postural control and visual dysfunction of the anterior or posterior part of the visual system. METHODS: Data resulting from ophthalmologic, orthoptic, neurological, neuro-radiological, and ethological investigations of more than 313 neurologically impaired children were retrospectively analyzed. RESULTS: Abnormal postural control related to ocular and ocular motor disorders consisted of anomalous head control and subsequent abnormal head posture and torticollis. The abnormal postural control related to retrochiasmatical damage of the visual system consisted of a torticollis combined with adjustment of the upper part of the body, as if at the same time adapting to a combination of defects and optimizing residual visual functions. CONCLUSION: Visual dysfunctions play a distinct role in the postural control of children with CP.

Adolescent↗
PubMed2004

Differential localization of hamartin and tuberin and increased S6 phosphorylation in a tuber.

In a tuberous sclerosis patient with a mutation in the TSC1 tumor suppressor gene, no second-hit mutation was found in a resected cortical tuber. Tuber giant cells showed predominantly nuclear hamartin, cytosolic tuberin, and hyperphosphorylation of S6. Differential accumulation of hamartin and tuberin in separate cellular compartments of giant cells may prevent formation of the hamartin-tuberin complex, resulting in increased S6 phosphorylation. These data provide an alternative mechanism for tuberogenesis.

Cerebral Cortex↗
PubMed2004

Functional consequences of hemispherectomy.

Using the International Classification of Functioning Disability and Health (ICF) (WHO, 2001), impairments, activities and social participation are reported in 12 children (mean age at surgery 5.9 years) who were investigated before and three times over a 2-year period after hemispherectomy. Impairments were assessed (i) in terms of seizure frequency (Engel classification) and seizure severity (HASS) and (ii) with respect to muscle strength (MRC), range of motion (JAM score) and muscle tone (modified Ashworth scale). Activities were assessed in terms of gross motor functioning (GMFM) and self-care, mobility and social function (PEDI). Participation was assessed in terms of epilepsy-related restrictions and quantified by means of the Hague Restrictions in Childhood Epilepsy Scale (HARCES). Nine out of 12 children could be classified as free of seizures (Engel class I), and in the remaining three seizure frequency was Engel class III. HASS scores showed maximum improvement in 10 out of 12 children and near-maximum improvement in the two remaining children. Muscle strength and muscle tone on the side of the body contralateral to the hemispherectomy, which were already decreased preoperatively, decreased even further in the first 6 months after surgery, but returned to the presurgical baseline thereafter, except for the distal part of the arm. Range of motion was abnormal prior to operation and remained so after operation. Mean GMFM increase was 20% after 2 years (95% confidence interval 10-33); all five dimensions improved statistically significantly (P < 0.05). Mean PEDI increase was more than 20 scale points (95% confidence interval 10-35); again, all domains improved significantly (P < 0.05). In nearly all children, HARCES scores had normalized 2 years after surgery. In conclusion, decrease of seizure frequency and severity widens the scope of motor and social functioning, which overrides the effects of remaining motor impairments.

Child↗
PubMed2004

Interrater agreement of the diagnosis and classification of a first seizure in childhood. The Dutch Study of Epilepsy in Childhood.

OBJECTIVE: To assess the interrater agreement of the diagnosis and the classification of a first paroxysmal event in childhood. METHODS: The descriptions of 100 first paroxysmal events were submitted to two panels each consisting of three experienced paediatric neurologists. Each observer independently made a diagnosis based on clinical judgment and thereafter a diagnosis based on predefined descriptive criteria. Then, the observers discussed all patients within their panel. The agreement between the six individual observers was assessed before discussion within each panel and after that, between the two panels. RESULTS: Using their clinical judgement, the individual observers reached only fair to moderate agreement on the diagnosis of a first seizure (mean (SE) kappa 0.41 (0.03)). With use of defined descriptive criteria the mean (SE) kappa was 0.45 (0.03). The kappa for agreement between both panels after intra-panel discussion increased to 0.60 (0.06). The mean (SE) kappa for the seizure classification by individual observers was 0.46 (0.02) for clinical judgment and 0.57 (0.03) with use of criteria. After discussion within each panel the kappa between the panels was 0.69 (0.06). In 24 out of 51 children considered to have had a seizure, agreement was reached between the panels on a syndrome diagnosis. However, the epileptic syndromes were in most cases only broadly defined. CONCLUSIONS: The interrater agreement on the diagnosis of a first seizure in childhood is just moderate. This phenomenon hampers the interpretation of studies on first seizures in which the diagnosis is only made by one observer. The use of a panel increased the interrater agreement considerably. This approach is recommended at least for research purposes. Classification into clinically relevant syndromes is possible only in a very small minority of children with a single seizure.

Child↗
PubMed2002

Diazepam-enhanced beta activity in Sturge Weber syndrome: its diagnostic significance in comparison with MRI.

OBJECTIVES: This study was performed to assess the extent of functional involvement of the affected hemisphere in Sturge Weber syndrome in comparison with the uninvolved hemisphere. To this end beta activity in the electroencephalogram (EEG) was measured, both before and after administration of diazepam intravenously (i.v.). METHODS: In 9 patients asymmetry in beta band activity was studied before and after diazepam administration. Several beta bands and asymmetry parameters were calculated. beta band asymmetries were compared with structural abnormalities (magnetic resonance imaging, MRI). RESULTS: Total beta activity was reduced in the involved hemisphere in all patients after diazepam administration. In 3 patients functional abnormalities were found in brain regions that were structurally intact. CONCLUSIONS: Decreased diazepam-enhanced beta activity in the EEG is a sensitive criterion of functional abnormality. In patients with subtle structural abnormalities diazepam-enhanced EEG may have added value in diagnosing functional involvement and in monitoring disease progression in patients.

Adolescent↗
PubMed2002

Breath holding spells in a 3-day-old neonate: an unusual early presentation in a family with a history of breath holding spells.

Breath holding spells are common in childhood. They peak about 2 years of age and abate by 5 years of age; they are rare before 6 months of age. We report a case of cyanotic breath holding spells starting at the age of 3 days. There was a family history of breath holding spells including a three-year-old brother, patient's father, his sister, and the paternal great grandfather. Pharmacological intervention with iron replacement therapy and piracetam was not successful. We want to draw attention to the fact that breath holding spells should be included in the differential diagnosis of neonatal cyanotic spells. The course of these neonatal breath holding spells is thought to be "benign", but nevertheless, severe breath holding spells can pose problems for parents and clinicians.

Cyanosis↗
PubMed2002

Distribution of glutamate transporters in the hippocampus of patients with pharmaco-resistant temporal lobe epilepsy.

In patients suffering from temporal lobe epilepsy (TLE), increased extracellular glutamate levels in the epileptogenic hippocampus both during and after clinical seizures have been reported. These increased glutamate levels could be the result of malfunctioning and/or downregulation of glutamate transporters (also known as EAATs; excitatory amino acid transporters). In this study, the distribution of protein and mRNA of EAAT subtypes was examined in the hippocampus of TLE patients with hippocampal sclerosis (HS group) and without hippocampal sclerosis (non-HS group), and in autopsy controls without neurological disorders. EAAT protein localization was studied by immunohistochemistry on paraffin sections using specific poly- and monoclonal antibodies against the glial glutamate transporters EAAT1 and EAAT2 and the neuronal glutamate transporter EAAT3. Antibody specificity was shown by immunoblotting. In the HS group, a small decrease in EAAT1-immunoreactivity (IR) was observed in CA4 and in the polymorphic and supragranular layer of the dentate gyrus, compared with the control group. The strongest changes were found for EAAT2 levels. In the non-HS group, increased EAAT2-IR was detected in the CA1 and CA2 field, compared with non-epileptic controls. EAAT2-IR was decreased in the HS compared with the non-HS group. Fewer EAAT3-positive cells were found in the HS group than in the non-HS and control group. In both TLE groups, increased EAAT3 levels were observed in individual neurones. In the HS group, the percentage of EAAT3-IR neurones was increased in CA2 and in the granule cell layer of the dentate gyrus. Radioactive in situ hybridization for EAAT1-3 confirmed our immunohistochemical results. Non-radioactive in situ hybridization showed that not only astrocytes, but also neurones express EAAT2 mRNA. Taken together, differences in both mRNA and protein levels of glutamate transporter subtypes were found in specific regions in the TLE hippocampus, with most severe changes found for EAAT2 and EAAT3 levels. The results indicate an upregulation of EAAT2 protein expression in CA1 and CA2 in neurones in the non-HS group. This is in line with decreased EAAT2 protein levels in the HS group, since these hippocampi are characterized by severe neuronal cell loss. The functional consequences (glutamate transport capacity) of the reported changes in EAAT2 and EAAT3 remain to be determined.

Adult↗
PubMed2001

The variety of visual perceptual impairments in pre-school children with perinatal brain damage.

To study the selectivity of visual perceptual impairment in children with early brain injury, eight visual perceptual tasks (L94), were administered to congenitally disabled children both with and without risk for cerebral visual impairment (CVI). The battery comprised six object-recognition and two visuoconstructive tasks. Seven tasks were newly designed. For these normative data are presented (age 2.75-6.50 years). Because the recognition tasks required object naming, each item included a canonical control drawing and visual perceptual ability was evaluated relative to the non-verbal intelligence level, instead of chronological age. In 22 multiple disabled children with no indications of CVI, the frequency of impairment did not exceed that in the reference sample for any L94 task. In contrast, in 57 5-year-old children who were at risk for CVI due to pre-maturity or birth asphyxia, a significant increase in the frequency of impairment was seen on six L94 tasks (range 12-38%). However, only five children had more than two impairments, indicating that the deficits were selective, not pervasive. We conclude that early brain lesions interfere with the functioning of particular visual subsystems, yet leave other subsystems intact and functioning within the normal range.

Agnosia↗
PubMed2001

The existence of two sources in rolandic epilepsy: confirmation with high resolution EEG, MEG and fMRI.

In benign rolandic epilepsy seizure semiology suggests that the epileptic focus resides in the lower sensorimotor cortex. Previous studies involving dipole modeling based on 32 channel EEG have confirmed this localization. These studies have also suggested that two distinct dipole sources are required to adequately describe the typical interictal spikes. Since in benign epilepsy invasive validation is prohibited, this study tries to further establish these results using a multi-modal approach, involving 32 channel EEG, high resolution 84 channel EEG, 151 channel MEG and fMRI. From one patient interictal spikes were recorded and analyzed using the MUSIC algorithm in a realistic volume conductor model. In an fMRI experiment the same patient performed voluntary tongue movements, thus mimicking a typical seizure. Results show that EEC, MEG and fMRI localization converge on the same area in the lower part of the sensorimotor cortex, and that high resolution EEG clearly reveals two distinct sources, one in the post- and one in the pre-central cortex.

Brain Mapping↗
PubMed2001

Prevalence of cerebral palsy in The Netherlands (1977-1988).

Children with cerebral palsy (CP) and their families often make strong demands on diagnostic, therapeutic, technical and social facilities. Prevalence estimates are needed to improve treatment and services. As recent Dutch data are not available, the present study aimed to assess the population prevalence of CP in the Netherlands. A representative Dutch area with 1.2 million inhabitants of which 172,000 were born between 1977 and 1988 was studied. To ascertain the children with CP from these birth years, medical practices (such as rehabilitation centres, paediatric and child neurological departments) were consecutively asked to contact their (supposed) CP cases. Next, a parents' organisation and finally regional news media assisted in the ascertainment. In total, 170 'supposed' CP cases underwent an expert examination. Of these 170, 127 children proved to be definite CP-cases, yielding a 'crude' average prevalence of 0.74 per 1,000 inhabitants (95% CI: 0.61-0.87). Under-ascertainment was recognised and quantified. Accordingly, the population prevalence of CP over the birth year period 1977-1988 was calculated as 1.51 per 1,000 inhabitants (average over the 12 birth years). The calculated CP prevalence rose significantly over time: from 0.77 (1977-1979) to 2.44 (1986-1988). This trend is in accordance with other studies.

Adolescent↗
PubMed2000

Fetal pain?

During the last few years a vivid debate, both scientifically and emotionally, has risen in the medical literature as to whether a fetus is able to feel pain during abortion or intrauterine surgery. This debate has mainly been inspired by the demonstration of various hormonal or motor reactions to noxious stimuli at very early stages of fetal development. The aims of this paper are to review the literature on development of the pain system in the fetus, and to speculate about the relationship between "sensing" as opposed to "feeling" pain and the number of reactions associated with painful stimuli. While a cortical processing of pain theoretically becomes possible after development of the thalamo-cortical connections in the 26th week of gestation, noxious stimuli may trigger complex reflex reactions much earlier. However, more important than possible painfulness is the fact that the noxious stimuli, by triggering stress responses, most likely affect the development of an individual at very early stages. Hence, it is not reasonable to speculate on the possible emotional experiences of pain in fetuses or premature babies. A clinically relevant aim is rather to avoid and/or treat any possibly noxious stimuli, and thereby prevent their potential adverse effects on the subsequent development.

Brain↗