Torstein Vik - Academia.edu (original) (raw)

Papers by Torstein Vik

Background/Aim: There are few reports on speech abilities and language understanding in children ... more Background/Aim: There are few reports on speech abilities and language understanding in children with CP. In this study we want to describe speech abilities, language understanding and use of alternative or augmented communication (AAC) in a national cohort of children with CP in Norway. We will also describe how we can identify children with CP at an early age, which will need AAC interventions. Material and methods: Data on 294 children with CP in Norway born between 01.01.96 and 31.12.98 were included, representing 79% of all cases registered during the observation period. Median age at registration was 6.9 years (1.9-10.2 years). CP subtype, cognitive development, speech, language understanding and use of augmented or alternative communication were recorded. Perinatal data were obtained from the Medical Birth Registry of Norway. Guidelines for early identification of AAC needs in children with CP based on this research are developed. Results: 72 % of the children had normal or i...

Acta Paediatrica, 2015

Apolipoprotein E (apoE) influences repair and other processes in the brain, and the apoE4 variant... more Apolipoprotein E (apoE) influences repair and other processes in the brain, and the apoE4 variant is a risk factor for Alzheimer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease and for prolonged recovery following traumatic brain injury. We previously reported that specific single nucleotide polymorphisms in the APOE or TOMM40 genes affecting the structure and production of apoE were associated with epilepsy, more impaired hand function and gastrostomy tube feeding in children with cerebral palsy (CP). This study explored how various combinations of the same polymorphisms may affect these clinical manifestations. Successful DNA analyses of APOE and TOMM40 were carried out on 227 children. The CP Register of Norway provided details of gross and fine motor function, epilepsy and gastrostomy tube feeding. Possible associations between these clinical manifestations and various combinations of the APOEε2, ε3 or ε4 alleles and of the rs59007384 polymorphism in the TOMM40 gene were explored. Epilepsy, impaired fine motor function and gastrostomy tube feeding were less common in children carrying the combination of rs59007384 GG and APOEε2 or ε3 than in children with other combinations. Our findings suggest that specific combinations of genes influence the structure and production of apoE differently and affect the clinical manifestations of CP.

European Journal of Paediatric Neurology, 2015

To use case-parent triad data to investigate if cerebral palsy (CP) is associated with variants o... more To use case-parent triad data to investigate if cerebral palsy (CP) is associated with variants of the APOE gene, the rs59007384 SNP of the TOMM40 gene or combined haplotypes of the two genes. DNA was analyzed in buccal swabs from 235 children with CP, their parents and a sibling. The relative risks (RR) with 95% confidence intervals (CI) that the children would have a distribution of APOE genotypes, rs59007384 variants or combined haplotypes deviating from Mendelian inheritance were estimated. Children with CP were more likely than expected to carry the APOEε3 allele (RR 7.5; CI: 0.99-53.7 for heterozygotes and 10.3; CI: 1.4-79.6 for homozygotes), and to have the haplotype of APOEε3 and rs59007384 G (RR 2.4; CI: 1-5.7 for heterozygotes, RR 3.7; CI: 1.4-9.5 for homozygotes) whereas the distribution was as expected for rs59007384 alone. In the subgroup analyses the findings were confined to children born preterm. Among siblings the distribution of these genes was as expected according to Mendelian inheritance. We speculate that children with APOEε2/APOEε4 alleles are more likely to die following cerebral injury in utero, resulting in a higher than expected proportion of children with CP carrying the APOEε3 allele.

The Journal of Pediatrics, 2014

Objectives To examine brain volumes and cortical surface area and thickness and to relate these b... more Objectives To examine brain volumes and cortical surface area and thickness and to relate these brain measures to cognitive function in young adults born small for gestational age (SGA) at term compared with non-SGA control patients.

Pediatric Radiology, 1998

Trials, 2014

Background: Cerebral palsy (CP) is the most common motor disability in childhood (2 to 3 per 1000... more Background: Cerebral palsy (CP) is the most common motor disability in childhood (2 to 3 per 1000 live births), and is frequently accompanied by cognitive impairments and behavioural problems. Children with CP are at increased risk of attention deficit disorder with or without hyperactivity (Attention Deficit Disorder (ADD)/Attention Deficit Hyperactivity Disorder (ADHD)) including working memory deficits. The primary aim of this study is to evaluate if cognitive training may improve working memory in children with CP. Methods/Designs: The study is an investigator-blinded, randomized controlled trial with a stepped-wedge design that will include 115 schoolchildren with CP. Eligible for participation are children with CP, aged 7 to 15 years, who are able to follow instructions and handle a computer mouse. Exclusion criteria are the presence of photosensitive epilepsy, Gross Motor Function Classification System (GMFCS) level V (most severe CP) (Phys Ther 80: [974][975][976][977][978][979][980][981][982][983][984][985] 2000) and severe visual or hearing impairments. Following assessment of eligibility and baseline cognitive assessment the participants will be randomized to either cognitive working memory training or treatment-as-usual ('control group'). The intervention is a computer-based working memory training program consisting of 25 daily sessions to be performed over a 5 to 6-week period at home. A neuropsychological assessment will be performed before and 4 to 6 weeks after completed training. When the latter assessment has been completed in the intervention group, the 'control group' will start on the same training program. Both groups will meet for a final neuropsychological assessment six months after completed training by an examiner unaware of group adherence.

Pediatric Research, 1997

We studied the nitric oxide-cGMP pathway in endothelium-dependent relaxation in femoral arterial ... more We studied the nitric oxide-cGMP pathway in endothelium-dependent relaxation in femoral arterial rings from piglets at different postnatal ages. Responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were examined in phenylephrine-precontracted rings from newborn (10-22-h) and 7 d (7-10-d)-old piglets. Relaxant responses were investigated in endothelium-denuded rings and endothelium-intact controls, and in endothelium-intact rings incubated with the nitric oxide synthase (NOS) inhibitor N(G)-monomethyl-L-arginine acetate (L-NMMA), indomethacin, or the superoxide anion generator 6-anilinoquinoline-5,8-quinone (LY83583). Arterial rings from both age groups relaxed to a similar degree in response to ACh. Relaxation in rings from newborn piglets was insensitive to NOS inhibition by L-NMMA, whereas in artery rings from 7-d-old piglets, the relaxant response was significantly inhibited by L-NMMA. Incubation with LY83583 gave an inhibition of ACh-induced relaxation very similar to that of L-NMMA. Incubation with indomethacin had no significant effect on ACh-induced relaxation in either age group. Artery rings from both age groups relaxed 100% to SNP; the 7-d-old group was more sensitive than the newborn. NOS inhibition potentiated SNP-induced relaxation in both groups, but the potentiating effect was of greater magnitude in the newborn. Our results indicate a difference in the mechanism(s) underlying ACh-induced relaxation in the femoral artery from newborn and 7-d-old piglets, with an intact relaxant response in rings from the newborn despite NOS inhibition. The SNP results indicate a down-regulated soluble guanylate cyclase in the newborn, possibly related to a difference in basal NO release between the two age groups.

Pediatric Research, 2004

Background: Meconium may cause lung injury (meconium aspiration syndromeϭMAS). Treatment is sympt... more Background: Meconium may cause lung injury (meconium aspiration syndromeϭMAS). Treatment is symptomatic by ventilatory support or in the worst cases extracorporal membrane oxygenation (ECMO). The pathophysiology is complex including a substantial inflammatory reaction in the lungs, but according to our results this inflammation may be systemic as well. We recently showed for the first time that meconium is a potent activator of complement (Castellheim A. et al. Pediatr. Res. 2004;55:310 -318), leading us to hypothesize that complement activation is an essential part of the pathophysiology of MAS.

Pediatric Research, 1994

We investigated early postnatal changes of the mesenteric circulation and its relationship to the... more We investigated early postnatal changes of the mesenteric circulation and its relationship to the systemic circulation in two groups of newborn infants. Group I (n = 10) was studied before the first feeding at 1 h and preprandially at 6 and 24 h. Group I1 (n = 10) was studied before the first feeding at 2 h of age and preprandially and postprandially at d 3, 4, and 5. Blood flow velocity was measured with ultrasound Doppler in the superior mesenteric artery (SMA), middle cerebral artery, subclavian artery, and aortic orifice for cardiac output (CO) calculations. Blood pressure and heart rate were monitored. SMA mean velocity (Vmean) decreased from 1 [0.33 5 0.07 m/s (mean -c SD)] to 6 h (0.23 -c 0.08 m/s,p c 0.005) in group I, probably due to ductal steal, returning to the 1-h value at 24 h. In contrast, middle cerebral artery Vmean remained unchanged in the first 24 h. From d 3, SMA Vmean increased 92% postprandially, with no relation to increasing amounts of food. The postprandial increase in SMA Vmean was not associated with changes in CO and blood pressure; however, a fall in relative mesenteric vascular resistance suggested regional redistribution of CO. Middle cerebral artery Vmean increased from h 2 to d 3 with a further increase on d 4 (p < 0.01). This increase was associated with an increase in blood pressure. The relative fraction of CO to middle cerebral artery increased during the first days of life, suggesting a redistribution of blood flow to the metabolically active organs in the neonatal period. (Pediufr Res 36: 334-339, 1994) Abbreviations Vmean, mean velocity BFV, blood flow velocity EDFV, end diastolic flow velocity During the first days of life, the intestinal circulation must adapt to feeding and to changes occurring in the postnatal transitional circulation. Ultrasound imaging and Doppler techniques permit noninvasive studies of the circulatory adaptive changes during the early period after birth. Studies on superior mesenteric artery BFV by Van Be1 e t al.

Pediatric Radiology, 2005

Pediatric Radiology, 1992

Cerebral MRI was performed at 1.5 T in 27 infants with birth weight below 1500 grams at i year of... more Cerebral MRI was performed at 1.5 T in 27 infants with birth weight below 1500 grams at i year of corrected age. The images were compared to those reported on normal development at the same age. On T1 weighted images, 20 (74.1%) of the 27 infants showed myelin deposition different from what has been reported to be normal. Areas most affected were the central occipital white matter and the centrum semiovale. Both correspond to ,,watershed areas" known to be at risk for periventricular leukomalacia in preterm infants. T2-weighted images showed delayed myelination in the same areas as described for T1. In addition, two infants showed delayed myelination in the central occipital white matter and one in the centrum semiovale. Patchy focal abnormalities involving the white matter were seen in seven (25.9 %) infants. Mild cerebral atrophy, mainly of the cortex was found in 10 (37.0 %) infants. Irregular shape of the lateral ventricles, especially of the occipital horns was present in 12 infants (44.4 %). 11 of these infants also had deviating changes in myelination. Only 2 infants (7.4 % ) had a normal MRI examination. Follow-up MRI examinations are needed to determine whether the high percentage of changes in myelination represent delayed development or brain damage in preterm infants.

Pediatric Radiology, 2006

Background: Children with very low birth weight (VLBW) have a significantly increased risk of lat... more Background: Children with very low birth weight (VLBW) have a significantly increased risk of later neurodevelopmental problems, while infants born small for gestational age (SGA) at term are also at some risk of developing neurological impairment. Objective: To investigate possible brain metabolite differences in adolescents with VLBW, SGA at term and controls by proton in vivo magnetic resonance spectroscopy (MRS) at 1.5 T. Materials and methods: MR spectra were acquired from volumes localized in the left frontal lobe, containing mainly white matter (54 subjects). Peak areas of N-acetyl aspartate (NAA), choline (Cho) and creatine (Cr) were determined, and the peak area ratio of NAA to Cr, total Cho to Cr, or NAA to Cho calculated. Probabilistic neural network (PNN) analysis was performed utilizing the chemical shift region containing resonances from NAA, Cho and Cr as inputs. Results: No significant difference in the peak area ratios could be found using the Kruskal-Wallis test. By application of PNN, a correct classification of 52 of the 54 adolescents with a sensitivity and specificity exceeding 93% for all groups was achieved. Conclusion: Small, yet systematic, differences in brain metabolite distribution among the groups were confirmed by PNN analysis.

Pediatric Neurology, 2005

To explore associations between psychiatric symptoms and cerebral magnetic resonance imaging abno... more To explore associations between psychiatric symptoms and cerebral magnetic resonance imaging abnormalities in low-birth-weight adolescents, 55 very low-birth-weight (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;or=1500 gm), 54 term small for gestational age (birth weight &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10th centile) and 66 term control adolescents (birth weight &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=10th centile) were assessed at 14-15 years of age. Outcome measures were Schedule for Affective Disorders and Schizophrenia for School-Age Children, Attention-Deficit/Hyperactivity Disorder Rating Scale IV, Autism Spectrum Screening Questionnaire, and qualitatively assessed cerebral magnetic resonance images. The very low-birth-weight group manifested increased prevalence of psychiatric symptoms and disorders compared with controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), especially symptoms of attention-deficit/hyperactivity disorder, and high frequency of ventricular dilatation, white matter reduction, thinning of corpus callosum, and gliosis (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01 vs controls). The Attention-Deficit/Hyperactivity Disorder Rating Scale score was significantly associated with white matter reduction and thinning of corpus callosum in this group. The term small for gestational age group had increased prevalence of psychiatric symptoms compared with control subjects, but not more frequent abnormalities on cerebral magnetic resonance imaging. In conclusion, attention-deficit/hyperactivity disorder symptoms were significantly associated with white matter reduction and thinning of corpus callosum in very low-birth-weight adolescents. No associations were found for other psychiatric symptoms and brain abnormalities in any of the groups.

Pediatric Nephrology, 2000

In children with chronic renal failure treated conservatively by dialysis or by transplantation, ... more In children with chronic renal failure treated conservatively by dialysis or by transplantation, various alterations of the nutritional, metabolic and fluid homeostasis may occur that may critically affect the patients' acute and chronic well-being. In the past, the assessment of body composition in children was hampered by insufficient precision, standardization and/or availability of appropriate anthropometric tools. Recently, there have been several methodological advances that may facilitate close and precise monitoring of body composition in this population. Specifically, the use of body mass index (BMI) data in children has become possible by the introduction of pediatric reference values processed for the calculation of standard deviation scores accounting for the skewed distribution of BMI. Skewness-adapted reference data have also been provided for percentage fat mass as assessed by multisite skinfold measurements. In addition, bioelectrical impedance analysis has been validated in healthy children as well as in pediatric dialysis and renal transplant populations. This novel auxological technique provides a highly reproducible, non-invasive and inexpensive way of assessing changes in total body water content in dialysed patients, as well as changes in fat and fat-free mass prior to dialysis and after renal transplantation.

Neuropediatrics, 1997

In this follow-up study, 20 of a geographically based year cohort of 31 surviving non-disabled VL... more In this follow-up study, 20 of a geographically based year cohort of 31 surviving non-disabled VLBW (birthweight &amp;lt; 1500 g) children were examined at six years of age. The aim of the study was to relate cerebral MRI findings to neuro-development in these non-disabled children at six years of age. All MRI scans were evaluated for myelination pattern, periventricular gliosis, ventricular dilation and cortical atrophy. The Peabody motor test and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) were used in the evaluation of motor, mental and perceptual function. A diagnosis of attention deficit disorder with hyperactivity was made based on the examiner&amp;#39;s impression of the child during the examination and based on the parent&amp;#39;s history. We found that ten (50%) of the children had periventricular gliosis, mainly in centrum semiovale (CS) (nine children) and in central occipital white matter (COW) (six children). Gliosis in CS was related to lower scores on the Peabody gross motor test for locomotion, indicating involvement of corticospinal tracts. Additional gliosis in COW was related to both fine motor and gross motor impairments. We speculate that this indicates damage to both motor and visual pathways, affecting eye-hand coordination and balance function. No relationship between MRI deviations at six years and mental function based on performance, verbal and total IQ scores was found. However, there was a significant relationship between periventricular gliosis in COW and C5 and low scores on the WPPSI performance subtests: Picture completion test and Block design test. This may indicate visual and spatial perception problems, caused by damage to posterior visual pathways and occipito-thalamic tracts dealing with visuo-motor integration.

Neuropediatrics, 1993

Thirty-one (77.5%) of a year cohort of 40 surviving infants with birth weight &amp;lt; 15... more Thirty-one (77.5%) of a year cohort of 40 surviving infants with birth weight &amp;lt; 1500 grams were seen on follow-up examination at one year of corrected age. At neurological evaluation 20 infants were normal (Group 1), seven infants were considered at risk (Group 2), and four infants had cerebral palsy (Group 3). Assessment on the Bayley Scales gave significantly lower mean scores in Group 3 compared with Group 1, both on the Mental Index (63 versus 102, p &amp;lt; 0.001) and on the Psychomotor Index (PDI) (60 versus 94, p &amp;lt; 0.005). Mean PDI score in Group 2 was significantly lower than in Group 1 (74 versus 94, p &amp;lt; 0.005). Cerebral MRI was performed in 27 infants. Of the 19 infants in Group 1 examined with MRI, 14 infants showed deviating changes in both myelin deposition and maturation (2). In all 14 infants the central occipital white matter was affected and in three infants also the centrum semiovale, both areas correspond to predilection sites for periventricular leukomalacia (PVL). Five infants had irregular shape of the occipital horns of the lateral ventricles. These findings may also represent the end stages of PVL (4). Only four out of seven infants were examined with MRI in Group 2. However, three infants had deviating myelination and three had irregular shape of the posterior horns. In Group 3 all infants were examined with MRI and all had deviating myelination and irregular and slightly dilated posterior horn. There was a significant correlation between abnormally dilated occipital horns seen with MRI, and cerebral palsy and low scores on the Denver and the Bayley tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatology, 1997

During the first week of life, we examined the changes in the systemic, intestinal and cerebral c... more During the first week of life, we examined the changes in the systemic, intestinal and cerebral circulation, and the circulatory responses to feeding in 10 small for gestational age (SGA) infants using the ultrasound Doppler technique. From day 1 to day 3, preprandial cardiac output decreased (p &amp;amp;amp;lt; 0.01), whereas mean blood pressure (p &amp;amp;amp;lt; 0.01), superior mesenteric artery mean flow velocity (Vmean; p &amp;amp;amp;lt; 0.01) and middle cerebral artery Vmean (p &amp;amp;amp;lt; 0.01) increased. On day 1, cardiac output was higher in the SGA than in those of term and preterm appropriate for gestational age infants reported from our laboratory. Preprandial superior mesenteric artery Vmean was inversely related to the degree of growth retardation (r = 0.63, p &amp;amp;amp;lt; 0.05). However, growth retardation did not influence the postprandial increase in superior mesenteric artery Vmean and end-diastolic flow velocity, or the cerebral circulation.

Journal of the International Neuropsychological Society, 2014

Reduced IQ, learning difficulties and poor school performance have been reported in small-for-ges... more Reduced IQ, learning difficulties and poor school performance have been reported in small-for-gestational-age (SGA) subjects. However, few studies include a comprehensive neuropsychological assessment. Our aim was to study neuropsychological functioning in young adults born SGA at term. A comprehensive neuropsychological test battery was administered to 58 SGA subjects (birth weight &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10th centile) born at term, and 81 term non-SGA controls (birth weight ≥10th centile). The SGA group obtained significantly (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .01) lower scores on the attention, executive and memory domains compared to non-SGA controls and showed higher risk of obtaining scores below -1.5 SD on the memory domain (odds ratio = 13.3, 95% confidence interval: 1.57, 112.47). At a subtest level, the SGA group obtained lower scores on most neuropsychological tests, with significant differences on 6 of 46 measures: the Trail Making Test 3 (letter sequencing), the Wechsler Memory Scale mental control and the auditory immediate memory scale, the Design Fluency, the Stroop 3 (inhibition) and the Visual Motor Integration (VMI) motor coordination subtest. Young adults born SGA score more poorly on neuropsychological tests compared with non-SGA controls. Differences were modest, with more significant differences in the memory domain.