H Stroink

Canisius-Wilhelmina Ziekenhuis, Nymegen, Gelderland, Netherlands

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Publications (78)312.32 Total impact

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    ABSTRACT: Background: The epilepsies are a clinically heterogeneous group of neurological disorders. Despite strong evidence for heritability, genome-wide association studies have had little success in identification of risk loci associated with epilepsy, probably because of relatively small sample sizes and insufficient power. We aimed to identify risk loci through meta-analyses of genome-wide association studies for all epilepsy and the two largest clinical subtypes (genetic generalised epilepsy and focal epilepsy). Methods: We combined genome-wide association data from 12 cohorts of individuals with epilepsy and controls from population-based datasets. Controls were ethnically matched with cases. We phenotyped individuals with epilepsy into categories of genetic generalised epilepsy, focal epilepsy, or unclassified epilepsy. After standardised filtering for quality control and imputation to account for different genotyping platforms across sites, investigators at each site conducted a linear mixed-model association analysis for each dataset. Combining summary statistics, we conducted fixed-effects meta-analyses of all epilepsy, focal epilepsy, and genetic generalised epilepsy. We set the genome-wide significance threshold at p<1·66 × 10–8. Findings: We included 8696 cases and 26 157 controls in our analysis. Meta-analysis of the all-epilepsy cohort identified loci at 2q24.3 (p=8·71 × 10–10), implicating SCN1A, and at 4p15.1 (p=5·44 × 10–9), harbouring PCDH7, which encodes a protocadherin molecule not previously implicated in epilepsy. For the cohort of genetic generalised epilepsy, we noted a single signal at 2p16.1 (p=9·99 × 10–9), implicating VRK2 or FANCL. No single nucleotide polymorphism achieved genome-wide significance for focal epilepsy. Interpretation: This meta-analysis describes a new locus not previously implicated in epilepsy and provides further evidence about the genetic architecture of these disorders, with the ultimate aim of assisting in disease classification and prognosis. The data suggest that specific loci can act pleiotropically raising risk for epilepsy broadly, or can have effects limited to a specific epilepsy subtype. Future genetic analyses might benefit from both lumping (ie, grouping of epilepsy types together) or splitting (ie, analysis of specific clinical subtypes).
    The Lancet Neurology 07/2014; · 23.92 Impact Factor
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    ABSTRACT: We present a neurodegenerative disorder starting in early childhood of two brothers consisting of severe progressive polyneuropathy, severe progressive cerebellar atrophy, microcephaly, mild epilepsy, and intellectual disability. The cause of this rare syndrome was found to be a homozygous mutation (c.1250_1266dup, resulting in a frameshift p.Thr424GlyfsX48) in PNKP, identified by applying homozygosity mapping and whole-genome sequencing. Mutations in PNKP have previously been associated with a syndrome of microcephaly, seizures and developmental delay (MIM 613402), but not with a neurodegenerative disorder. PNKP is a dual-function enzyme with a key role in different pathways of DNA damage repair. DNA repair disorders can result in accelerated cell death, leading to underdevelopment and neurodegeneration. In skin fibroblasts from both affected individuals, we show increased susceptibility to apoptosis under stress conditions and reduced PNKP expression. PNKP is known to interact with DNA repair proteins involved in the onset of polyneuropathy and cerebellar degeneration; therefore, our findings explain this novel phenotype.
    Neurogenetics 12/2012; · 3.58 Impact Factor
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    ABSTRACT: Intractability in epilepsy is difficult to define, and little is known about its onset, course, and duration. We investigated these aspects (as well as the occurrence of intractability) during long-term follow-up in patients with epilepsy, focusing on possible explanations for the variation in time of onset and duration of intractability. After diagnosis, 453 patients with childhood-onset epilepsy had a 5-year follow-up with regular visits and data collection. Ten years later they received a questionnaire with items concerning epilepsy, which was completed by 413 patients resulting in a mean follow-up of 15 years. Intractability during the first 5 years was compared with that in the last year of follow-up. Intractability was defined as having no 3-month remission during a 1-year period despite adequate medical treatment. At least 12.1% of the cohort had a period of intractability during the 15-year follow-up, and 8.5% were intractable in the final year. Of the patients with idiopathic etiology 4.3% had a period of intractability versus 17.0% for those with cryptogenic, and 22.6% for those with remote symptomatic etiology (p < 0.001). Other risk factors at baseline were younger age at first seizure, generalized cryptogenic/symptomatic or localization-related symptomatic epilepsy, mental retardation, and febrile convulsions before enrollment. The cumulative risk of a period of intractability was 6.1% (95% confidence interval [CI] 3.7-8.5) at 2 years follow-up and 8.2% (95% CI 5.4-11.0) at 5 years. The mean time to onset of intractability during the first 5 years of follow-up was 1.6 (95% CI 1.3-2.0; median 1.0) years and the mean duration of intractability during these 5 years was 3.3 (95% CI 2.8-3.8; median 3.6) years. Fifteen patients were intractable only during the first 5 years of follow-up (group A), and 19 subjects were intractable both during the first 5 years and the last year of follow-up (group B). Compared with group A, group B had shorter remission and a longer time to intractability during the first 5 years and more were intractable in the fifth year of follow-up. Sixteen other patients had a late onset of intractability after 5 years of follow-up, sometimes after long periods of remission (group C). No significant differences in baseline characteristics were found among groups A, B, and C, but slightly more children in groups B and C became mentally retarded during the follow-up. In all groups, antiepileptic drugs were of little use in preventing and ending intractability. There is a large unpredictable variation in time of onset, course, and duration of intractability, with a higher chance of final intractability after a poor course during the first 5 years of follow-up. The natural course of epilepsy probably best explains the variable course of intractability. The effect of medication seems to be minor.
    Epilepsia 03/2012; 53(4):741-51. · 3.96 Impact Factor
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    ABSTRACT: Acquired demyelinating syndromes (ADS) can be a first presentation of multiple sclerosis (MS) in children. The incidence of these disorders in Europe is currently unknown. Children (<18 years old) living in the Netherlands who presented with ADS were included from January 1, 2007 to December 31, 2010 by the Dutch pediatric MS study group and the Dutch surveillance of rare pediatric disorders. Demographic and clinical data were collected. Eighty-six patients were identified over 4 years, resulting in an incidence of 0.66/1,00,000 per year. Most patients presented with polyfocal ADS without encephalopathy (30%), followed by polyfocal ADS with encephalopathy (24%), optic neuritis (ON, 22%), monofocal ADS (16%), transverse myelitis (3%), and neuromyelitis optica (3%). Patients with polyfocal ADS with encephalopathy were younger (median 3.9 years) than patients with ON (median 14.6 years, p < 0.001) or monofocal ADS (median 16.0 years, p < 0.001). Patients with polyfocal ADS without encephalopathy (median 9.2 years) were also younger than monofocal ADS patients (median 16.0 years, p < 0.001). There was a slight female preponderance in all groups except the ON group, and a relatively large number of ADS patients (29%) reported a non-European ancestry. Familial autoimmune diseases were reported in 23%, more often in patients with relapsing disease than monophasic disease (46 vs. 15%, p = 0.002) and occurring most often in the maternal family (84%, p < 0.001). During the study period, 23% of patients were subsequently diagnosed with MS. The annual incidence of ADS in the Netherlands is 0.66/1,00,000 children/year. A polyfocal disease onset of ADS was most common.
    Journal of Neurology 02/2012; 259(9):1929-35. · 3.58 Impact Factor
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    ABSTRACT: Epilepsy may have far-reaching consequences for patients, other than having seizures and medication. At 15 years after diagnosis, this study investigates health perception, restrictions due to epilepsy, living arrangements (including marital status and offspring), and the educational and occupational attainment of patients with childhood-onset epilepsy. A total of 453 patients with epilepsy had a 5-year follow-up since diagnosis with regular visits and data collection. Ten years later, a questionnaire addressing epilepsy was completed by 413 patients, resulting in a mean follow-up of 15 years. Subjects were compared with age peers of the Dutch population for each etiologic group separately, and also for subjects with/without a 5-year terminal remission regardless of treatment. Age-adjusted standardized incidence rates were calculated for each variable. Subjects with normal intelligence had a health perception comparable with that of the general population, but significantly more subjects without remission had a worse health perception, especially those still using medication. Restrictions and symptoms due to epilepsy were reported by 14% of the subjects, mainly by those without remission or with ongoing medication. The living arrangement of subjects with idiopathic or cryptogenic etiology was similar to that of Dutch persons of the same age (age peers). Subjects with remote symptomatic etiology less often lived independently or with a partner, and more frequently resided in an institution or living group for the disabled. Those with and without remission were more often part of another household, mainly due (in both groups) to having a remote symptomatic etiology. Rates of having a partner and offspring were significantly reduced only for subjects with remote symptomatic etiology. Fewer students with idiopathic/remote symptomatic etiology and students in remission followed higher vocational or scientific education. In these latter groups, the highest attained education of employees was lower than expected. The employment status of subjects with idiopathic or cryptogenic etiology was comparable with that of their Dutch age peers, but fewer subjects with remote symptomatic etiology were employed and more of them were part of the dependent population. However, for those in the labor force (employed/unemployed) all employment rates were ≥90%, even for those with remote symptomatic etiology. Nevertheless, fewer employees than expected had a higher vocational or scientific level of occupation, even those with idiopathic etiology and those in remission. Health perception, living arrangement, and socioeconomic status were influenced by epilepsy, comorbidities, or treatment, particularly for subjects with remote symptomatic etiology or no remission. The group in remission fared less well than expected, mainly due to the numbers of subjects with remote symptomatic etiology in this group. In line with others, we conclude that childhood-onset epilepsy is associated with lower educational attainment, even for subjects with idiopathic etiology and subjects in remission; probably related to this, their occupational level was also lower than expected.
    Epilepsia 12/2011; 52(12):2192-202. · 3.96 Impact Factor
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    ABSTRACT: Periventricular haemorrhagic infarction (PVHI) is a complication of preterm birth associated with cardiorespiratory instability. To date, the role of thrombophilia as a possible additional risk factor in infants with atypical timing and presentation of PVHI has not been investigated. This was a retrospective cohort study of preterm infants who developed PVHI with an atypical timing and presentation either of antenatal onset or late in the postnatal course in the absence of a preceding sudden deterioration of their clinical condition. In infants with atypical PVHI mutation analysis of the factor V Leiden (G1691A), prothrombin (G20210A) gene, and C677T and A1298C polymorphisms in the MTHFR gene was performed, and plasma lipoprotein(a) and homocysteine levels were measured. Sixty-two preterm infants who presented with a PVHI were studied. Seventeen had an atypical presentation (seven males, 10 females; median birthweight 1170g [range 580-1990g]; median gestational age 30.6wks [range 28.7-33.7wks]). The typical PVHI group comprised 28 males and 17 females (median birthweight 1200g [range 670-2210g]; median gestational age 29.6wks [range 25.3-33.6wks]). Among the 17 infants with atypical presentation, the factor V Leiden mutation was found in seven infants (41%) as well as in the mothers of six of these seven infants; in one infant this was concomitant with a prothrombin gene mutation. A polymorphism in the MTHFR gene was also present in these infants. In two infants with an atypical presentation who were tested for this, a mutation in the COL4A1 gene was found (reported previously). All but two of the infants with an atypical presentation developed spastic unilateral cerebral palsy. An atypical presentation of PVHI in preterm infants tends to occur more often in the presence of thrombophilia. Testing of thrombophilia, especially factor V Leiden and prothrombin gene mutation, is recommended in these infants.
    Developmental Medicine & Child Neurology 11/2011; 54(2):140-7. · 2.68 Impact Factor
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    ABSTRACT: Introduction: Periventricular haemorrhagic infarction (PVHI) is a complication of preterm birth associated with cardiorespiratory instability. The role of thrombophilia as a possible additional risk factor in infants with an atypical presentation when PVHI was of presumed antenatal onset or > 96 h after birth in the absence of a preceding sudden deterioration, has not been investigated extensively.
    Pediatric Research 11/2011; · 2.67 Impact Factor
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    ABSTRACT: Relatively few SCN1A mutations associated with genetic epilepsy with febrile seizures-plus (GEFS+) and Dravet syndrome (DS) have been functionally characterized. In contrast to GEFS+, many mutations detected in DS patients are predicted to have complete loss of function. However, functional consequences are not immediately apparent for DS missense mutations. Therefore, we performed a biophysical analysis of three SCN1A missense mutations (R865G, R946C and R946H) we detected in six patients with DS. Furthermore, we compared the functionality of the R865G DS mutation with that of a R859H mutation detected in a GEFS+ patient; the two mutations reside in the same voltage sensor domain of Na(v) 1.1. The four mutations were co-expressed with β1 and β2 subunits in tsA201 cells, and characterized using the whole-cell patch clamp technique. The two DS mutations, R946C and R946H, were nonfunctional. However, the novel voltage sensor mutants R859H (GEFS+) and R865G (DS) produced sodium current densities similar to those in wild-type channels. Both mutants had negative shifts in the voltage dependence of activation, slower recovery from inactivation, and increased persistent current. Only the GEFS+ mutant exhibited a loss of function in voltage-dependent channel availability. Our results suggest that the R859H mutation causes GEFS+ by a mixture of biophysical defects in Na(v) 1.1 gating. Interestingly, while loss of Na(v) 1.1 function is common in DS, the R865G mutation may cause DS by overall gain-of-function defects.
    European Journal of Neuroscience 08/2011; 34(8):1268-75. · 3.75 Impact Factor
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    ABSTRACT: To determine long-term outcome in a cohort of children with newly diagnosed benign childhood epilepsy with centrotemporal spikes (BECTS). 29 children with BECTS were included in the Dutch Study of Epilepsy in Childhood. Each child was followed for 5 years, and subsequently contacted 12-17 years after enrolment to complete a structured questionnaire. Twenty children had typical BECTS, nine had atypical BECTS (age at onset <4 years, developmental delay or learning difficulties at inclusion, other seizure types, atypical EEG abnormalities). Mean age at onset of epilepsy was 8.0 years with slight male preponderance. Most common seizure-types before enrolment were generalized tonic-clonic seizures (GTCS) and simple partial seizures; in 86% of the children seizures occurred during sleep. After 12-17 years, 96% had a terminal remission (TR(F)) of more than 5 years and 89% of more than 10 years. Mean duration of epilepsy was 2.7 years; mean age at reaching TR(F) was 10.6 years. Many children (63%) had experienced one or more (secondary) GTCS. Antiepileptic drugs were used by 79% of the children with a mean duration of 3.0 years. None of the children seemed to have developed learning problems or an arrest of cognitive development during follow-up. No significant differences were observed in patient characteristics or outcome between children with typical BECTS and children with atypical BECTS. All children in our cohort, both those with typical and atypical BECTS, had a very good prognosis with high remission rates after 12-17 years. None of the predictive factors for disease course and outcome observed in earlier studies (other seizure types, age at onset, multiple seizures at onset) were prognostic in our cohort.
    Seizure 10/2010; 19(8):501-6. · 2.00 Impact Factor
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    ABSTRACT: To study the course and outcome of childhood-onset epilepsy during 15-year follow-up (FU). We extended FU in 413 of 494 children with new-onset epilepsy recruited in a previously described prospective hospital-based study by questionnaire. Mean FU was 14.8 years (range 11.6-17.5 years). Five-year terminal remission (TR) was reached by 71% of the cohort. Course during FU was favorable in 50%, improving in 29%, and poor or deteriorating in 16%. Mean duration of seizure activity was 6.0 years (range 0-21.5 years), strongly depending on etiology and epilepsy type. Duration was <1 year in 25% of the cohort and exceeded 12 years in another 25%. Antiepileptic drugs (AEDs) were used by 86% during a mean of 7.4 years: one-third had their last seizure within 1 year of treatment, and one-third continued treatment at the end, although some had a 5-year TR. At last contact, 9% of the cohort was intractable. In multivariate analysis, predictors were nonidiopathic etiology, febrile seizures, no 3-month remission, and early intractability. Eighteen patients died; 17 had remote symptomatic etiology. Standardized mortality ratio for remote symptomatic etiology was 31.6 [95% confidence interval (CI) 18.4-50.6], versus 0.8 [95% CI 0.02-4.2] for idiopathic/cryptogenic etiology. In most children with newly diagnosed epilepsy, the long-term prognosis of epilepsy is favorable, and in particular, patients with idiopathic etiology will eventually reach remission. In contrast, epilepsy remains active in approximately 30% and becomes intractable in approximately 10%. AEDs probably do not influence epilepsy course; they merely suppress seizures. Mortality is significantly higher only in those with remote symptomatic etiology.
    Epilepsia 07/2010; 51(7):1189-97. · 3.96 Impact Factor
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    ABSTRACT: Fatigue is an important symptom in adult multiple sclerosis (MS) and it is likely to occur in children with MS. It is currently unknown whether children who experienced a monophasic inflammatory demyelinating event of the central nervous system in the past also suffer from fatigue. We studied the presence and severity of fatigue in 32 children (18 boys, 14 girls) between 11-17 years old (mean: 14 years, 10 months) with a monophasic inflammatory demyelinating disease (n=22) or definite MS (n=10). This was measured with the Checklist Individual Strength. A score of >or=40 on the severity of fatigue subscale indicated the presence of severe fatigue. We also examined the relation between fatigue and depression (assessed by the Child Depression Inventory). Additionally we measured the health-related quality of life (HRQoL), using the TNO-AZL Child Quality of Life child form. We compared the scores of the MS and monophasic patients with the scores of healthy Dutch children. The highest scores on the fatigue scales subjective fatigue and physical activity were found in the children with MS. Only 1 of the monophasic patients suffered from severe fatigue in contrast to 4 of the MS patients. In the MS group fatigue and depression were correlated. MS patients experienced a lower HRQoL on the scales locomotor functioning, cognitive functioning and interaction with peers. The occurrence of fatigue is very rare after a monophasic inflammatory demyelinating event in the past. As expected, fatigue occurs more frequent in paediatric MS patients.
    European journal of paediatric neurology: EJPN: official journal of the European Paediatric Neurology Society 10/2009; 14(4):320-5. · 2.01 Impact Factor
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    ABSTRACT: We determined long-term outcome and the predictive value of baseline and EEG characteristics on seizure activity evolution in 47 children with newly diagnosed childhood absence epilepsy (CAE) included in the Dutch Study of Epilepsy in Childhood. All children were followed for 12-17 years. The children were subdivided in three groups for the analyses: those becoming seizure-free (I) within 1 month after enrolment; (II) 1-6 months after enrolment; and (III) more than 6 months after enrolment or having seizures continuing during follow-up. No significant differences were observed between groups in sex, age at onset, occurrence of febrile seizures, and positive first-degree family history for epilepsy. All groups had high remission rates after 12-17 years. Significantly more relapses occurred in group III than in group I. Total duration of epilepsy and mean age at final remission were 3.9 and 9.5 years, respectively, being significantly longer and higher in group III than in groups I and II. In all groups only a small number of children (total 13%) developed generalized tonic-clonic seizures. In conclusion, our children with CAE had an overall good prognosis with few children (7%) still having seizures after 12-17 years. Remission rate in children with CAE cannot be predicted on the basis of baseline and EEG characteristics. The early clinical course (i.e. the first 6 months) has some predictive value with respect to the total duration of absence epilepsy.
    Epilepsy research 02/2009; 83(2-3):249-56. · 2.48 Impact Factor
  • European Journal of Paediatric Neurology - EUR J PAEDIATR NEUROL. 01/2009; 13.
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    ABSTRACT: In 3 young male patients, aged 10, 19 and 21 years respectively, sequential, severe, painless bilateral visual loss occurred. Ophthalmological examination revealed no other abnormalities and this delayed the diagnosis Leber's hereditary optic neuropathy (LHON). LHON is a mitochondrial genetic disease characterised by bilateral acute or subacute painless loss of central vision. LHON causes blindness, predominantly in young adult males but less frequently in women and children as well. Occasionally, LHON is associated with other neurological and cardiac changes. The first patient recovered his vision within 2 years, but the other 2 remained blind. All 3 patients had a m.11778G > A mutation in the mitochondrial DNA (mtDNA). Over 95% of LHON cases are primarily the result of one of three mitochondrial DNA point mutations. In addition, analysis of patients grouped according to mtDNA mutation has demonstrated differences in both the clinical features of visual failure and in recurrence risks for relatives that are associated with each of the pathogenic mtDNA mutations. Depending on the type of mutation, recovery of vision occurs in 4-58% of the patients. Whilst pathogenic mtDNA mutations are required for the development of LHON, other factors must be responsible for the variable penetrance and male predominance. Familiarity with the clinical spectrum of LHON is necessary for early diagnosis. There is no proven treatment.
    Nederlands tijdschrift voor geneeskunde 11/2008; 152(43):2313-6.
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    ABSTRACT: To study the efficacy and tolerability of add-on levetiracetam in children and adolescents with refractory epilepsy. In this prospective multi-centre, open-label, add-on study, 33 children aged 4-16 years (median 8.5 years) with epilepsy refractory to at least two antiepileptic drugs were treated with levetiracetam in addition to their present treatment regimen with a follow-up of 26 weeks. The starting dose of 10 mg/kg/day was increased with 2-week steps of 10 mg/kg/day, if necessary, up to a maximum dose of 60 mg/kg/day. Retention rate was 69.7% after 26 weeks on a median levetiracetam dosage of 22 mg/kg/day. Four children dropped-out because levetiracetam was ineffective, four because seizure frequency increased and/or seizures became more severe, and two because they developed aggressive behaviour. Compared to their baseline seizure frequency, 13 children (39.4%) had a >50% seizure reduction 12 weeks after initiation of levetiracetam, and 17 children (51.5%) at 26 weeks. At 26 weeks, nine children (27.3%) had been seizure-free for at least the last 4 weeks, terminal remission ranged from 0 to 187 days (mean 46 days). Levetiracetam was effective in both partial and primary generalized seizures, but had most effect in partial seizures. Most reported side effects were hyperactivity (48.5%), somnolence (36.4%), irritability (33.3%) and aggressive behaviour (27.3%). Severity of most side effects was mild. Five children had a serious adverse event, which all concerned hospital admissions that were not related to levetiracetam use. Levetiracetam proved to be an effective and well-tolerated add-on treatment in this group of children with refractory epilepsy.
    European Journal of Paediatric Neurology 07/2008; 12(4):321-7. · 1.98 Impact Factor
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    ABSTRACT: To identify clinical, radiologic, or CSF factors that predict conversion to multiple sclerosis (MS) after a first attack of inflammatory demyelination in children. In this nationwide retrospective multicenter study in the Netherlands, 117 children below age 16 were included. Fifty-four children presented with a monofocal clinically isolated syndrome (CIS) and 63 children with a polyfocal CIS (PCIS). A second MS-defining attack occurred in 43% of the CIS cases, compared to 21% of the patients with PCIS onset (p < 0.006). Basal ganglia and thalamic lesions and lesions larger than 2 cm on MRI (considered typical of ADEM) were observed during PCIS, irrespective of the presence of encephalopathy. No significant difference in developing MS was found in children with PCIS with or without encephalopathy. Elevated IgG index and presence of oligoclonal CSF bands were more often observed in children who developed MS. Both Barkhof and KIDMUS MRI criteria shared a high specificity and had a high positive predictive value for conversion to MS. In children under the age of 10, the Barkhof criteria had a higher sensitivity than the KIDMUS criteria, but still lower than in older children. Barkhof and KIDMUS MRI criteria share a high specificity and positive prognostic value for conversion to multiple sclerosis (MS). Sensitivity of these criteria is poor, especially in children below 10 years of age. Basal ganglia lesions can occur in patients who later develop MS. A substantial number of patients presenting with polyfocal onset and no encephalopathy remained monophasic.
    Neurology 07/2008; 71(13):967-73. · 8.25 Impact Factor
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    ABSTRACT: We report a patient with phakomatosis pigmentovascularis IIb and numerous iris hamartomas. Phakomatosis pigmentovascularis IIb is characterized by the simultaneous occurrence of a nevus flammeus, a mongolian spot, and sometimes a nevus anemicus in the same individual, with systemic involvement. To our knowledge, the association with multiple iris hamartomas has been reported only once. This second patient suggests that the association might be more common. Additional reports will indicate if such an association is more frequent than is now assumed.
    Pediatric Dermatology 01/2008; 13(1):33-5. · 1.04 Impact Factor
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    H. Stroink
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    ABSTRACT: Many people suffer from one or more epileptic seizures during life, but not all these people have epilepsy. Moreover, epilepsy is not one disease or syndrome, but a collection of different disorders, which have in common the repeated occurrence of unprovoked epileptic seizures during some time in life.There are many genetically determined and acquired causes of epilepsy. The symptomatology of the seizures can be very different. Also the course in time of epilepsies is very diverging. The cause, symptoms, signs and course are influenced to a great deal by age. Therefore, the epilepsies in childhood and in adulthood differ in many aspects. For this reason, children and adults should not be mixed in studies on epilepsy.
    Social Science & Medicine Part F Medical and Social Ethics 01/2008;
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    ABSTRACT: To study course and outcome of epilepsy in children having had a status epilepticus (SE) as the presenting sign or after the diagnosis. A total of 494 children with newly diagnosed epilepsy, aged 1 month through 15 years, were followed prospectively for 5 years. A total of 47 Children had SE. Forty-one of them had SE when epilepsy was diagnosed. For 32 (78%), SE was the first seizure. SE recurred in 13 out of 41 (32%). Terminal remission at 5 years (TR5) was not significantly worse for these 41 children: 31.7% had a TR5 <1 year versus 21.2% of 447 children without SE. They were not more often intractable. Five out of six children with first SE after diagnosis had a TR5 <1 year. Mortality was not significantly increased for children with SE. Independent factors associated with SE at presentation were remote symptomatic and cryptogenic etiology, and a history of febrile convulsions. Children with first SE after inclusion more often had symptomatic etiology. Although we find a trend for shorter TR5 in children with SE at presentation, outcome and mortality are not significantly worse. Etiology is an important factor for prognosis. Children with SE during the course of their epilepsy have a worse prognosis and a high recurrence rate of SE. This outcome is not due to the SE itself, but related to the etiology and type of epilepsy. The occurrence of SE is just an indicator of the severity of the disease.
    Epilepsia 10/2007; 48(9):1708-15. · 3.91 Impact Factor
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    ABSTRACT: Considering that the role of colour in photosensitive epilepsy (PSE) remains unclear, we designed a study to determine the potential of different colours, colour combinations and white light to trigger photoparoxysmal responses (PPRs) under stringent controlled conditions. After assessing their photosensitivity to stroboscopic white light and black and white patterns, we studied 43 consecutive PSE patients (mean age 19 years, 34 women), using a specially designed colour stimulator. Stimuli included: pulse trains between 10 and 30 Hz of white light and of all primary colours, and also isoluminant alternating time-sequences of colours. Illuminance was kept constant at 100 lux. A progressive stepwise increase of the modulation-depth (MD) of the stimuli was used to determine PPRs threshold. Whereas all the 43 patients were found to be sensitive during the stroboscopic and pattern protocol, only 25 showed PPRs (Waltz's score >2) at least in one session when studied with the colour stimulator. Coloured stimuli elicited PPRs in all these patients, whereas white light did so only in 17 patients. Of the primary colours, red elicited more PPRs (54 in 22 patients) and at a lower MD (max Z-score 0.93 at 10 Hz). Of the alternating sequences, the red-blue was the most provocative stimulus, especially below 30 Hz (100% of patients, max Z-score: 1.65 at 15 Hz). Blue-green was the least provocative stimulus, since it elicited only seven PPRs in seven (28%) patients (max Z-score 0.44 at 10 Hz). Sensitivity to alternating colours was not correlated to sensitivity to individual colours. We conclude that colour sensitivity follows two different mechanisms: one, dependent on colour modulation, plays a role at lower frequencies (<30 Hz). Another, dependent on single-colour light intensity modulation correlates to white light sensitivity and is activated at higher frequencies. Our results suggest that the prescription of spectacles with coloured lenses, tailored to the patient, can be an effective preventative measure against visually induced seizures.
    Brain 07/2007; 130(Pt 6):1679-89. · 9.92 Impact Factor

Publication Stats

2k Citations
312.32 Total Impact Points

Institutions

  • 2009–2012
    • Canisius-Wilhelmina Ziekenhuis
      Nymegen, Gelderland, Netherlands
  • 2005–2012
    • Erasmus MC
      • Department of Neurology
      Rotterdam, South Holland, Netherlands
  • 2008–2010
    • University of Groningen
      • Department of Neurology
      Groningen, Province of Groningen, Netherlands
    • Radboud University Medical Centre (Radboudumc)
      Nymegen, Gelderland, Netherlands
  • 2002–2008
    • St. Elisabeth Ziekenhuis Tilburg
      Tilburg, North Brabant, Netherlands
  • 1991–2002
    • Erasmus Universiteit Rotterdam
      • Department of Pediatric Urology
      Rotterdam, South Holland, Netherlands
  • 1997–2001
    • Leiden University Medical Centre
      • Department of Neurology
      Leiden, South Holland, Netherlands
  • 2000
    • Het Oogziekenhuis Rotterdam
      Rotterdam, South Holland, Netherlands