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Dive into the research topics where Janjaap van der Net is active.

Publication


Featured researches published by Janjaap van der Net.


Arthritis Care and Research | 2011

Validation of a new pediatric joint scoring system from the International Hemophilia Prophylaxis Study Group: Validity of the hemophilia joint health score

Brian M. Feldman; Sharon Funk; Britt-Marie Bergstrom; N. Zourikian; P. Hilliard; Janjaap van der Net; Raoul H.H. Engelbert; Pia Petrini; H. Marijke van den Berg; Marilyn J. Manco-Johnson; Georges E. Rivard; A. Abad; Victor S. Blanchette

Repeated hemarthrosis in hemophilia causes arthropathy with pain and dysfunction. The Hemophilia Joint Health Score (HJHS) was developed to be more sensitive for detecting arthropathy than the World Federation of Hemophilia (WFH) physical examination scale, especially for children and those using factor prophylaxis. The HJHS has been shown to be highly reliable. We compared its validity and sensitivity to the WFH scale.


Pediatric Rehabilitation | 2006

Physical function and fitness in long-term survivors of childhood leukaemia.

Marco van Brussel; Tim Takken; Janjaap van der Net; Raoul H.H. Engelbert; Marc Bierings; M.A.G.C. Schoenmakers; Paul J. M. Helders

Objective: To evaluate the physical function and fitness in survivors of childhood leukaemia 5–6 years after cessation of chemotherapy. Materials and methods: Thirteen children (six boys and seven girls; mean age 15.5 years) who were treated for leukaemia were studied 5–6 years after cessation of therapy. Physical function and fitness were determined by anthropometry, motor performance, muscle strength, anaerobic and aerobic exercise capacity. Results: On motor performance, seven of the 13 patients showed significant problems in the hand-eye co-ordination domain. Muscle strength only showed a significantly lower value in the mean strength of the knee extensors. The aerobic and the anaerobic capacity were both significantly reduced compared to reference values. Conclusion: Even 5–6 years after cessation of childhood leukaemia treatment, there are still clear late effects on motor performance and physical fitness. Chemotherapy-induced neuropathy and muscle atrophies are probably the prominent cause for these reduced test results. Physical training might be indicated for patients surviving leukaemia to improve fitness levels and muscle strength.


Psycho-oncology | 2009

Development, feasibility and efficacy of a community-based exercise training program in pediatric cancer survivors.

Tim Takken; Patrick van der Torre; Marlies Zwerink; E. Hulzebos; Marc Bierings; Paul J. M. Helders; Janjaap van der Net

Objective: The aim of this study was to develop a 12‐week exercise training program (comprising aerobic and strength exercises), and to study the feasibility and efficacy of this exercise program in children who survived acute lymphoblastic leukemia.


Quality of Life Research | 2000

Cultural differences in functional status measurement: Analyses of person fit according to the Rasch model

Jan W.H. Custers; Herbert Hoijtink; Janjaap van der Net; Paul J. M. Helders

For many reasons it is preferable to use established health related outcome instruments. The validity of an instrument, however, can be affected when used in another culture or language other than what it was originally developed. In this paper, the outcome on functional status measurement using a preliminary version of the Dutch translated ‘Pediatric Evaluation of Disability Inventory’ (PEDI) was studied involving a sample of 20 non-disabled Dutch children and American peers, to see if a cross-cultural validation procedure is needed before using the instrument in the Netherlands. The Rasch model was used to analyse the Dutch data. Score profiles were not found to be compatible with the score profiles of American children. In particular, ten items were scored differently with strong indications that these were based on inter-cultural differences. Based on our study, it is argued that cross-cultural validation of the PEDI is necessary before using the instrument in the Netherlands.


Arthritis & Rheumatism | 2008

Responsiveness of exercise parameters in children with inflammatory myositis

Tim Takken; Janjaap van der Net; Raoul H.H. Engelbert; Suzanne Pater; Paul J. M. Helders

OBJECTIVE Juvenile dermatomyositis (DM) is an inflammatory myopathy in which the immune system targets the microvasculature of the skeletal muscle and skin, leading to significant muscle weakness and exercise intolerance, although the precise etiology is unknown. The goal of this study was to investigate the changes in exercise capacity in children with myositis during active and inactive disease periods and to study the responsiveness of exercise parameters. METHODS Thirteen children with juvenile DM (mean+/-SD age 11.2+/-2.6 years) participated in this study. Patients performed a maximal exercise test using an electronically braked cycle ergometer and respiratory gas analysis system. Exercise parameters were analyzed, including peak oxygen uptake (VO2peak), peak work rate (Wpeak), and ventilatory anaerobic threshold (VAT). All children were tested during an active period of the disease and during a remission period. From these data, 4 different response statistics were calculated. RESULTS The children performed significantly better during a remission period compared with a period of active disease. Most exercise parameters showed a very large response. The 5 most responsive parameters were Wpeak, Wpeak (percent predicted), oxygen pulse, VO2peak, and power at the VAT. CONCLUSION We found in our longitudinal study that children with active juvenile DM had significantly reduced exercise parameters compared with a remission period. Moreover, we found that several parameters had very good responsiveness. With previously established validity and reliability, exercise testing has been demonstrated to be an excellent noninvasive instrument for the longitudinal followup of children with myositis.


Pediatric Rehabilitation | 2003

Creating and being created: the changing panorama of paediatric rehabilitation

Paul J. M. Helders; Raoul H. H. Engelbert; Jan W. H. Custers; Jan Willem Gorter; Tim Takken; Janjaap van der Net

Paediatric rehabilitation as a discipline is rapidly changing, especially during the last decades. In the past, paediatric rehabilitation was characterized by merely adult intervention strategies in a miniaturized form, delivered by a merely adult patients-oriented profession. Theories on childhood development, however, changed, as did the focus of interventions: from impairments to function, from the child itself to family, community and peers. The call for outcome-oriented and evidence-based medicine lastly, changed paediatric rehabilitation into a mature paediatric profession with its own scientific framework. This is reflected among other things in the increasing number of paediatric measures and instruments specifically geared to the paediatric rehabilitation profession, for example the Gross Motor Function Measure, Paediatric Evaluation of Disability Inventory and Movement ABC. More recently, paediatric exercise physiologists are pointing to the benefits of an active lifestyle and training for patients with chronic diseases and disabilities. Several studies have evaluated the effects of such training programmes and came up with positive results. It shows that paediatric rehabilitation continues to develop as a dynamic profession, having growth, childhood development and childhood activities as its core business.


Pediatric Rheumatology | 2008

Motor performance and functional ability in preschool- and early school-aged children with Juvenile Idiopathic Arthritis: a cross-sectional study

Janjaap van der Net; Patrick van der Torre; Raoul H. H. Engelbert; Vivian Engelen; Femke van Zon; Tim Takken; Paul J. M. Helders

ObjectiveTo describe the level of motor performance and functional skills in young children with JIA.MethodsIn a cross-sectional study in 56 preschool-aged (PSA) and early school- aged children (ESA) with JIA according to ILAR classification, motor performance was measured with the Bayley Scales of Infant Development II (BSID2) and the Movement Assessment Battery for Children (M-ABC). Functional skills were measured with the Pediatric Evaluation of Disability Inventory (PEDI). Disease outcome was measured with a joint count on swelling/range of joint motion, functional ability and joint pain.ResultsTwenty two PSA children (mean age 2.1 years) with a mean Developmental Index of the BSID2 of 77.9 indicating a delayed motor performance; 45% of PSA children showed a severe delayed motor performance. Mean PEDI scores were normal, 38% of PSA scored below -2 SD in one or more domains of the PEDI. Thirty four ESA children (mean age 5.2 years) with a mean M-ABC 42.7, indicating a normal motor performance, 12% of ESA children had an abnormal score. Mean PEDI scores showed impaired mobility skills, 70% of ESA children scored below -2 SD in one or more domains of the PEDI. Disease outcome in both age groups demonstrated low to moderate scores. Significant correlations were found between age at disease onset, disease duration and BSID2 or M-ABC and between disease outcome and PEDI in both age cohorts.ConclusionMore PSA children have more impaired motor performance than impaired functional skills, while ESA children have more impairment in functional skills. Disease onset and disease duration are correlated with motor performance in both groups. Impaired motor performance and delayed functional skills is primarily found in children with a polyarticular disease course. Clinical follow up and rehabilitation programs should also focus on motor performance and functional skills development in young children with JIA.


Early Human Development | 2012

Prevalence and predictors of idiopathic asymmetry in infants born preterm

Jacqueline Nuysink; Ingrid C. van Haastert; Maria J.C. Eijsermans; Corine Koopman-Esseboom; Janjaap van der Net; Linda S. de Vries; Paul J. M. Helders

BACKGROUND An idiopathic asymmetry in posture of the head is recognized as a risk factor to develop a deformational plagiocephaly (DP). In our neonatal follow-up clinic, an IA is often observed in infants born preterm at term-equivalent age (TEA). AIMS To explore (1) the prevalence of an idiopathic asymmetry in 192 infants (gestational age ≤32.0 weeks) at TEA and 6 months corrected age (CA), (2) whether demographical, perinatal, and medical factors were predictors of the asymmetry, and (3) differences in motor maturation between infants with and without asymmetry. METHODS In a retrospective study, frequencies of idiopathic asymmetry and DP, putative predictors, and Alberta Infant Motor Scale scores at 6 months CA were abstracted and analyzed with Chi(2), Mann-Whitney, logistic regression and T-test. RESULTS The prevalence rate of a positional preference of the head at TEA was 44.8% (n=86), 10.4% (20/192) had a DP at TEA and 13% (25/192) at 6 months CA. Positional preference, multiple birth and male gender predicted the presence of DP (p<.05, odds ratio 3.0, 3.2, and 3.1 respectively). Gross motor maturity at 6 months CA was less developed in infants with a positional preference at TEA compared to preterm norms (p=0.01). CONCLUSIONS The high prevalence of a positional preference in infants born preterm at term equivalent age requires extra alertness to prevent the development of a deformational plagiocephaly, especially in boys and twins. Although, considering the lower prevalence of plagiocephaly at 6 months CA, therapists should be aware of over treating these infants.


Early Human Development | 2013

Prediction of gross motor development and independent walking in infants born very preterm using the Test of Infant Motor Performance and the Alberta Infant Motor Scale

Jacqueline Nuysink; Ingrid C. van Haastert; Maria J.C. Eijsermans; Corine Koopman-Esseboom; Paul J. M. Helders; Linda S. de Vries; Janjaap van der Net

BACKGROUND One objective of a neonatal follow-up program is to examine and predict gross motor outcome of infants born preterm. AIMS To assess the concurrent validity of the Test of Infant Motor Performance (TIMP) and the Alberta Infant Motor Scale (AIMS), the ability to predict gross motor outcome around 15 months corrected age (CA), and to explore factors associated with the age of independent walking. METHODS 95 infants, born at a gestational age <30 weeks, were assessed around 3, 6 and 15 months CA. At 3 months CA, correlations of raw-scores, Z-scores, and diagnostic agreement between TIMP and AIMS were determined. AIMS-score at 15 months CA and parental-reported walking age were outcome measures for regression analyses. RESULTS The correlation between TIMP and AIMS raw-scores was 0.82, and between Z-scores 0.71. A cut-off Z-score of -1.0 on the TIMP had 92% diagnostic agreement (κ = 0.67) with an AIMS-score < P10. Neither TIMP- nor AIMS-scores at 3 months CA were associated with the gross motor outcome at 15 months CA. The AIMS-scores at 6 months CA predicted the AIMS-scores at 15 months CA with an explained variance of 19%. Median walking age was 15.7 months CA, with which only the hazard ratio of the AIMS at 6 months CA and ethnicity were significantly associated. CONCLUSIONS Prediction of gross motor development at 15 months CA and independent walking was not possible prior to 6 months CA using the AIMS, with restricted predictive value. Cultural and infant factors seem to influence the onset of independent walking.


Baillière's clinical rheumatology | 1998

Pain in childhood rheumatic arthritis

W. Kuis; Cobi J. Heijnen; G. Sinnema; Annemieke Kavelaars; Janjaap van der Net; Paul J. M. Helders

Pain is a major symptom in chronic inflammatory arthropathies such as rheumatoid arthritis and affects the health status of arthritis patients negatively. There has been much debate about the role of pain in juvenile chronic arthritis and this review deals with the controversies about this subject. Pain in children is best understood as a multifactorial concept in which pain is the result of somatosensory, behavioural and environmental factors. The role of the different factors contributing to pain will be assessed with special reference to mechanisms relevant to children with chronic pain, the various instruments to measure pain, such as visual analogue scales and algometry, and the treatment of chronic pain in juvenile chronic arthritis. For a true understanding of chronic pain in children, these multidimensional assessments should be integrated into a biobehavioural model, by means of which a better understanding should lead to new therapeutic interventions for one of the most common symptoms of rheumatic diseases in childhood: pain.

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Lisa G. Rider

National Institutes of Health

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