Per Ivar Kaaresen

University Hospital of North Norway, Tromsø, Troms, Norway

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Publications (35)135.84 Total impact

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    ABSTRACT: Examine the effect of an early intervention programme on cognitive outcome at 7 and 9 years in children with birth weight (BW) <2000 g.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 09/2014; · 3.45 Impact Factor
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    ABSTRACT: There is an increased risk of heart failure and pulmonary edema in pregnancies complicated by hypertensive disorders. However, in a previous study we found that pregnancy protects against fibrosis and preserves angiogenesis in a rat model of angiotensin II induced cardiac hypertrophy. In this study we test the hypothesis that pregnancy protects against negative effects of increased afterload. Pregnant (gestational day 5.5-8.5) and non-pregnant Wistar rats were randomized to transverse aortic constriction (TAC) or sham surgery. After 14.2±0.14 days echocardiography was performed. Aortic blood pressure and left ventricular (LV) pressure-volume loops were obtained using a conductance catheter. LV collagen content and cardiomyocyte circumference were measured. Myocardial gene expression was assessed by real-time polymerase chain reaction. Heart weight was increased by TAC (p<0.001) but not by pregnancy. Cardiac myocyte circumference was larger in pregnant compared to non-pregnant rats independent of TAC (p = 0.01), however TAC per se did not affect this parameter. Collagen content in LV myocardium was not affected by pregnancy or TAC. TAC increased stroke work more in pregnant rats (34.1±2.4 vs 17.5±2.4 mmHg/mL, p<0.001) than in non-pregnant (28.2±1.7 vs 20.9±1.5 mmHg/mL, p = 0.06). However, it did not lead to overt heart failure in any group. In pregnant rats, α-MHC gene expression was reduced by TAC. Increased in the expression of β-MHC gene was higher in pregnant (5-fold) compared to non-pregnant rats (2-fold) after TAC (p = 0.001). Nine out of the 19 genes related to cardiac remodeling were affected by pregnancy independent of TAC. This study did not support the hypothesis that pregnancy is cardioprotective against the negative effects of increased afterload. Some differences in cardiac structure, function and gene expression between pregnant and non-pregnant rats following TAC indicated that afterload increase is less tolerated in pregnancy.
    PLoS ONE 01/2014; 9(2):e89559. · 3.53 Impact Factor
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    ABSTRACT: Knowledge about early physiotherapy to preterm infants is sparse, given the risk of delayed motor development and cerebral palsy. A pragmatic randomized controlled study has been designed to assess the effect of a preventative physiotherapy program carried out in the neonatal intensive care unit. Moreover, a qualitative study is carried out to assess the physiotherapy performance and parents' experiences with the intervention. The aim of the physiotherapy program is to improve motor development i.e. postural control and selective movements in these infants. 150 infants will be included and randomized to either intervention or standard follow-up. The infants in the intervention group will be given specific stimulation to facilitate movements based on the individual infant's development, behavior and needs. The physiotherapist teaches the parents how to do the intervention and the parents receive a booklet with photos and descriptions of the intervention. Intervention is carried out twice a day for three weeks (week 34, 35, 36 postmenstrual age). Standardized tests are carried out at baseline, term age and at three, six, 12 and 24 months corrected age. In addition eight triads (infant, parent and physiotherapist) are observed and videotaped in four clinical encounters each to assess the process of physiotherapy performance. The parents are also interviewed on their experiences with the intervention and how it influences on the parent-child relationship. Eight parents from the follow up group are interviewed about their experience. The interviews are performed according to the same schedule as the standardized measurements. Primary outcome is at two years corrected age. The paper presents the protocol for a randomized controlled trial designed to study the effect of physiotherapy to preterm infants at neonatal intensive care units. It also studies physiotherapy performance and the parent's experiences with the intervention. ClinicalTrials.gov NCT01089296.
    BMC Pediatrics 02/2012; 12:15. · 1.98 Impact Factor
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    ABSTRACT: The aim of this study was to examine the effectiveness of an early intervention program on behavioral outcomes at corrected age of 5 years for children with birth weights (BWs) of <2000 g. A randomized controlled trial of a modified version of the Mother-Infant Transaction Program was performed. Outcomes were measured by the Child Behavior Check List report (parents) and Strengths and Difficulties Questionnaire at 5 years (parents and preschool teachers). A total of 146 infants were assigned randomly (intervention group: 72 infants; reference group: 74 infants). A term group was recruited (75 infants). The mean BWs were 1396 ± 429 g for the intervention group, 1381 ± 436 g for the control group, and 3619 ± 490 g for the term reference group. Parents in the intervention group reported significantly fewer behavioral problems measured by both instruments at 5 years. There were no differences in behavior problems reported by preschool teachers. Significantly more children in the preterm control group scored within the clinical area of both instruments. This modified version of the Mother-Infant Transaction Program led to fewer behavioral problems reported by parents at corrected age of 5 years for children with BWs of <2000 g.
    PEDIATRICS 12/2011; 129(1):e9-e16. · 4.47 Impact Factor
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    ABSTRACT: Background and Aims: Prenatal inflammation and the fetal inflammatory response have been associated with preterm birth and subsequent neonatal lung and brain disorders. However, there is a paucity of information about the relation between prenatal infections and cognitive outcome in preterm children. The aim of this study was to examine the effect of prenatal inflammation on cognitive outcome at 5 years corrected age in low birthweight children.
    Pediatric Research 11/2011; · 2.67 Impact Factor
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    C Klingenberg, C E Isaksen, P I Kaaresen
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    ABSTRACT: Background and aims: Extra-uterine growth restriction is common among very preterm infants (VPI). Optimising enteral feeding is of critical importance to improve neurodevelopmental outcome. We aimed to assess the effect of a feeding regimen with a high enteral volume intake.
    Pediatric Research 11/2011; · 2.67 Impact Factor
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    ABSTRACT: Temperamental regulatory competence and social communication in term and preterm infants at 12 months corrected age was studied in a randomized controlled intervention trial aimed at enhancing maternal sensitive responsiveness. Surviving infants <2000 g from a geographically defined area were randomized to an intervention (71) or a control group (69), and compared with term infants (74). The intervention was a modified version of the "Mother-Infant Transaction Program". Regulatory competence was measured with the Infant Behavior Questionnaire, and social communication with the Early Social Communication Scales. Preterm intervention infants with low regulatory competence had higher responding to joint attention than preterm control infants. A sensitizing intervention may moderate the association between temperament and social communication, and thus allow an alternative functional outlet for preterm infants low in regulatory competence. The finding may have implications for conceptualizations of the role of early sensitizing interventions in promoting important developmental outcomes for premature infants.
    Infant behavior & development 09/2011; 35(1):140-9. · 1.34 Impact Factor
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    ABSTRACT: To examine the prevalence of neurodevelopmental disability and the predictive value of pre-, peri-, and postnatal data on neurologic, sensory, cognitive, and motor function in children born extremely preterm. This was a prospective observational study of all infants born in Norway between 1999 and 2000 with gestational ages between 22 and 27 weeks or birth weights between 500 and 999 g. Cognitive function was assessed with the Wechsler Preschool and Primary Scale of Intelligence-Revised, motor function with the Movement Assessment Battery for Children, and severity of cerebral palsy with the Gross Motor Function Classification for Cerebral Palsy. Disabilities were described as mild, moderate, or severe. Of 371 eligible children, 306 (82%) were examined at a mean (SD) age of 5 years and 10 (4) months. For gestational age less than 28 weeks (n = 239), 26 (11%) children had cerebral palsy alone (n = 21) or in combination with blindness (n = 3) or deafness (n = 2); 1 was blind and 1 was deaf. Of the remaining children, the mean full-scale IQ was 94 ± 15, and significant predictors were (values given as the difference in IQ points [95% confidence intervals]) high maternal education (9.6 [5.7-13.4]), preeclampsia (-7.7 [-12.7 to -2.7]), and retinopathy of prematurity higher than grade 2 (-17.5 [-27.1 to -8.0]). Movement Assessment Battery for Children scores were positively associated with gestational age and prenatal steroids and negatively associated with being small for gestational age, male gender, and having retinopathy of prematurity. Moderate to severe neurodevelopmental disability was more common for gestational ages 25 weeks or less (28 of 87 children) than for 26 to 27 weeks (12 of 152 children; P < .001) and 28 weeks or more (7 of 67 children; P = .001). The outcome was poorer for children with gestational ages of 25 weeks or less compared with those with gestational ages between 26 and 27 weeks. For those without cerebral palsy, blindness, or deafness, however, gestational age had a limited association with cognitive and motor function.
    PEDIATRICS 02/2011; 127(3):e630-8. · 4.47 Impact Factor
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    ABSTRACT: The goal was to examine the effectiveness of an early intervention on cognitive and motor outcomes at corrected ages of 3 and 5 years for children with birth weights (BWs) of <2000 g. A randomized controlled trial of a modified version of the Mother-Infant Transaction Program was performed. Outcomes were assessed with the Bayley Scales of Infant Development II and the Wechsler Preschool and Primary Scale of Intelligence-Revised at 3 and 5 years, respectively. McCarthy Scales of Children's Abilities and the grooved pegboard test were used to test motor outcomes at 5 years. A total of 146 infants were assigned randomly (intervention group: 72 infants; control group: 74 infants). The mean BWs were 1396 ± 429 g for the intervention group and 1381 ± 436 g for the control group. After adjustment for maternal education, a nonsignificant difference in Mental Developmental Index scores at 3 years of 4.5 points (95% confidence interval: -0.3 to 9.3 points) in favor of the intervention group was found, whereas the intervention effect on full-scale IQ scores at 5 years was 6.4 points (95% confidence interval: 0.6-12.2 points). Significantly more children in the intervention group had IQ scores of ≥ 85 at 3 and 5 years. There were no differences between the groups with respect to motor outcomes. This modified version of the Mother-Infant Transaction Program improved cognitive outcomes at corrected age of 5 years for children with BWs of <2000 g.
    PEDIATRICS 10/2010; 126(5):e1088-94. · 4.47 Impact Factor
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    ABSTRACT: Extreme prematurity carries a high risk of neurosensory disability. Examine which information obtained pre-, peri- and postnatally may be predictive of neurosensory disabilities at 2 years of age. Prospective observational study of all infants born in Norway in 1999 and 2000 with gestational age (GA) 22-27 completed weeks or birth weight (BW) of 500-999 g. Incidence of neurosensory disabilities. Of 373 surviving children, 30 (8%) had major neurosensory disabilities (26 CP, 6 blind, 3 deaf), and a further 46 (12%) had minor visual or hearing disabilities. The rate of major neurosensory disabilities was 19 of 99 (19%) for children with GA 23-25 vs. 8 of 189 (4%) for GA 26-27 weeks (p<0.001). In a multivariable model, only morbidities detected in the neonatal intensive care unit (NICU) were associated with major neurosensory disabilities; adjusted odds ratios (95% confidence intervals) were 68.6 (18.7, 252.2) for major abnormalities on cerebral ultrasound, 6.8 (1.7, 27.4) for retinopathy of prematurity (ROP) grade>2, 3.2 (1.0, 9.7) for ROP grade 1-2, 6.5 (1.9, 22.3) for prolonged use (> or = 21 days) of steroid treatment for lung disease and 3.1 (1.0, 9.4) for clinical chorioamnionitis. The visual outcome was strongly related to the degree of ROP (p<0.001), and all who had a normal hearing screen in the NICU had normal hearing at 2 years. NICU morbidities, rather than GA or intrauterine growth are the significant predictors of major neurosensory disabilities among extreme prematurity surviving to discharge from the NICU.
    Early human development 09/2010; 86(9):581-6. · 2.12 Impact Factor
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    ABSTRACT: Nordhov, S. M., Kaaresen, P. I., Rønning, J. A., Ulvund, S. E. & Dahl, L. B. (2010). A randomized study of the impact of a sensitizing intervention on the child-rearing attitudes of parents of low birth weight preterm infants. Scandinavian Journal of Psychology. The background for this study was that nurturant child-rearing attitudes are associated with positive development in low birth weight (LBW) infants. The objective was to study child-rearing attitudes and early intervention (EI) in parents of LBW infants from 12-36 months corrected age. LBW infants (BW < 2000 g) were randomized to an intervention (IG) or a control group (CG). The EI consisted of seven in-hospital sessions prior to discharge, then four home visits. A Child Rearing Practices Report was administered at 12 (mothers only), 24 and 36 months. A total of 146 infants were randomized. The mean BW in IG was 1396 (SD 429) g and 1381 (436) g in CG. The mean GA was 30.2 (3.1) weeks in IG and 29.9 (3.5) weeks in CG. Mothers in IG reported significantly more nurturant child-rearing attitudes at 12 and 24 months. There was a significant change in restrictive and nurturant attitudes over time. It was concluded that EI may lead to more nurturant child-rearing attitudes in mothers of preterms.
    Scandinavian Journal of Psychology 02/2010; · 1.29 Impact Factor
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    ABSTRACT: To assess if growth restricted (small for gestational age, SGA) extremely preterm infants have excess neonatal mortality and morbidity. This was a cohort study of all infants born alive at 22-27 weeks' post menstrual age in Norway during 1999-2000. Outcomes were compared between those who were SGA, defined as a birth weight less than the fifth percentile for post menstrual age, and those who had weights at or above the fifth percentile. Of 365 infants with a post menstrual age of <28 weeks, 31 (8%) were SGA. Among infants with a post menstrual age of <28 weeks, only chronic lung disease was associated with SGA status (OR 2.7, 95% CI 1.0 to 7.2). SGA infants with a post menstrual age of 26-27 weeks had excess neonatal mortality (OR 3.8, 95% CI 1.3 to 11), chronic lung disease and a significantly higher mean number of days (age) before tolerating full enteral nutrition. SGA infants with a post menstrual age of 22-25 weeks had an excess risk of necrotising enterocolitis. Extremely preterm SGA infants had excess neonatal mortality and morbidity in terms of necrotising enterocolitis and chronic lung disease.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 05/2009; 94(5):F363-7. · 3.45 Impact Factor
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    C. Klingenberg, P. I. Kaaresen, L. B. Dahl
    NeoReviews 01/2009; 10(7).
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    ABSTRACT: Mothers' reports of preterm and term infants' temperament from 6 to 12 months of age were studied, with intervention and stress as predictors. Preterm infants with a birth weight <2000g were randomized to an intervention (71) or a control (69) group. A control group of healthy term infants (74) was also established. The intervention was a modified version of the "Mother-Infant Transaction Program", aimed at sensitizing caregivers to the infants' individual characteristics. Temperament was measured with the Infant Behavior Questionnaire, and stress with the Parenting Stress Index. There were no group differences in temperament at 6 or 12 months or in change during the same period. There was a strong association between stress and negative reactivity in the preterm control group at 12 months. In the preterm intervention group, there were strong negative correlations between stress and regulatory competence at 6 months. The intervention seemed to change the relationship between stress and temperament. The strength of this association indicates that the intervention sensitized mothers to the temperamental regulatory competence of their preterm infants.
    Infant behavior & development 03/2008; 31(3):408-21. · 1.34 Impact Factor
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    ABSTRACT: Preterm infants are at increased risk of cognitive, motor and behavioral problems. Different intervention programs have been designed in an attempt to improve outcome, but the results are conflicting. To examine the effects of an early intervention program on cognitive, motor and behavioral problems and parenting stress among low birth weight children at 2 years corrected age. A randomized controlled trial was conducted including infants with a birth weight <2000 g treated at the University Hospital of North Norway, to examine the effects of a modified version of the Mother-Infant Transaction Program on cognitive, motor and behavioral outcomes and parenting stress. The children were assessed with the Bayley Scales of Infant Development and the Child Behavior Checklist/2-3 (CBCL) and the Parenting Stress Index were administered to the parents at 2 years corrected age. Sixty-nine children in the intervention group and 67 in the control group were assessed at 2 years. There were no differences between the groups in cognitive or motor outcomes. The intervention group scored consistently lower on all CBCL syndrome scales, but no difference was significant. The mothers in the intervention group reported significantly lower parental stress in both child and parent domain, whereas the fathers reported lower stress in child domain compared to the control group. This early intervention program does not improve cognitive, motor or behavioral outcomes at 2 years. There was a significant reduction in parenting stress reported by both mothers and fathers in the intervention group.
    Early Human Development 03/2008; 84(3):201-9. · 2.02 Impact Factor
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    ABSTRACT: Responsiveness in prematurely and term-born infants was studied cross-sectionally in relation to maternal confidence. Orientation and arousal were measured in 140 prematurely (mean BW 1,398 g, GA 30.1 weeks) and 75 term-born infants (mean BW 3,613 g, GA 39.3 weeks) with the Neonatal Behavioral Assessment Scales. Mothers filled out the Maternal Confidence Questionnaire and a modified version of the Parenting Stress Index. Prematurely born infants had a significantly lower level of arousal than term-born neonates. Responsiveness was not associated with maternal confidence. Lower confidence was associated with primiparity in both groups of mothers. Multiparous mothers of prematurely born infants had significantly lower levels of confidence than multiparous mothers of term-born infants. Confidence was significantly associated with stress for mothers of prematurely and term-born infants, and may be focused in follow-up after giving birth. Prematurely born infants should be examined more thoroughly in aspects of arousal at the time of discharge.
    Scandinavian Journal of Psychology 01/2008; 48(6):499-509. · 1.29 Impact Factor
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    ABSTRACT: This study audits the activity of the neonatal air transport team in Norway's two northernmost counties. Data on all air transports to or from the regional Neonatal Intensive Care (NICU) Unit within a 10-year period were collected. Two hundred and thirty-eight acute transports were conducted during the study period; 169 referrals to the NICU and 69 transfers to national surgical and cardiac centres. Only 13 very low birth weight infants were transported; the in utero transport rate was 95% for this patient population. The adjusted risk of death and/or intracranial haemorrhage for outborn very low birth weight infants was five-fold increased compared to those not transported postnatally. Babies with congenital heart disease comprised the one-fourth of all transports. The long-term mortality was 14% for the whole study population, and 29% for infants with congenital heart disease. Only seven deaths (3.2%) were defined as being transport-related; death during or within 24 h after transport. However, preventable complications like temperature instability, hypoglycaemia and hypo-/hypercapnia occurred in 10-20% of all transports. The transport related mortality was low in this study, however very low birth weight infants and infants with major congenital heart disease showed a relatively poor outcome.
    Acta Paediatrica 08/2007; 96(7):995-9. · 1.97 Impact Factor
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    New England Journal of Medicine 03/2007; 356(8):874; author reply 874. · 54.42 Impact Factor
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    ABSTRACT: This study tested the effects of optimized neonatal mother-infant transactions on joint attention performance at 12 months. Surviving infants <2000g from a geographically defined area were randomly assigned to a preterm intervention (n=71) or preterm control group (n=69). Comparisons were made between preterm groups, secondary with a term group (n=75). Joint attention was measured using the Early Social Communication Scales. Preterm intervention infants scored significantly higher than preterm control infants on elements Initiating Joint Attention (p<0.05), Initiating Object Requests (p<0.05), and Responding to Social Interaction (p<0.0005). Intervention was not associated with performance on elements Responding to Joint Attention, or on Responding to Requests. ELBW infants scored significantly lower than VLBW and LBW infants on imperative functions. Girls outperformed boys on all communication elements. An intervention implemented during the neonatal period can be of advantage for certain aspects of joint attention performance in preterm infants.
    Infant behavior & development 12/2006; 29(4):554-63. · 1.34 Impact Factor
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    ABSTRACT: Very low birth weight survivors are at increased risk of developing emotional and behavioral problems and low social and academic competencies. Information on such problems in very low birth weight adolescents is still sparse. Our purpose for this work was to study gender-specific emotional and behavioral problems and social and academic competencies in a cohort of very low birth weight adolescents in north Norway. Families with very low birth weight adolescents aged 13 to 18 years, born between 1978 and 1989 (n = 162) were addressed by mail and asked to complete the Child Behavior Check List and the Youth Self-Report. Data were compared with 2 normative adolescent populations (Child Behavior Check List, n = 540; Youth Self-Report, n = 2522). Scores given by very low birth weight adolescents and their parents on identical items in Child Behavior Check List and Youth Self-Report (cross-informant syndrome constructs) were compared in pairs. To explore predictive effects, demographic and early medical characteristics were entered into a hierarchical multiple regression analysis. There were 156 eligible families, and 99 (63.5%) responded. All completed the Child Behavior Check List, and 82 (52.6%) completed the Youth Self-Report. Very low birth weight boys reported less externalizing and internalizing behaviors and thought and attention problems and higher activity score, whereas very low birth weight girls reported less externalizing behavior and less social, thought, and attention problems and higher activity score compared with normative adolescents. Very low birth weight parents, however, reported more social and attention problems and less social and school competence in boys and more internalizing behavior and social and attention problems and less school competence in girls compared with normative parents. They scored high proportions of both genders within the borderline/clinical range on all of the scales, except for externalizing behavior and social problems in girls. Female very low birth weight adolescents, in contrast to males, reported more problems than parents when compared in pairs, and externalizing problems in particular were not recognized by parents. From parents' point of view, significant proportions of very low birth weight adolescents experience more emotional and behavioral problems and less competence than normative adolescents. In contrast, very low birth weight adolescents state less problems and similar or higher competence than normative adolescents. Very low birth weight adolescent girls report more emotional and behavioral problems compared with their parents than very low birth weight adolescent boys do. Externalizing problems in very low birth weight adolescent girls are often not recognized by parents. To better understand these seemingly paradoxical findings and to develop adequate intervention programs, there is a need for prospective longitudinal studies.
    PEDIATRICS 09/2006; 118(2):e449-59. · 4.47 Impact Factor

Publication Stats

666 Citations
135.84 Total Impact Points

Institutions

  • 2008–2014
    • University Hospital of North Norway
      Tromsø, Troms, Norway
  • 1998–2012
    • Universitetet i Tromsø
      • • Department of Health and Care Sciences
      • • Faculty of Health Sciences
      Tromsø, Troms Fylke, Norway
    • Nordlandssykehuset Bodoe
      Bodø, Nordland, Norway
  • 2011
    • University of Oslo
      • Department of Paediatrics
      Kristiania (historical), Oslo County, Norway
  • 2010–2011
    • University of Bergen
      • Department of Clinical Medicine
      Bergen, Hordaland Fylke, Norway
  • 2005
    • Oslo University Hospital
      Kristiania (historical), Oslo County, Norway