Olof Flodmark

Preterm Children Have Disturbances of White Matter at 11 Years of Age as Shown by Diffusion Tensor Imaging

Preterm birth frequently involves white matter injury and affects long-term neurologic and cognitive outcomes. Diffusion tensor imaging has been used to show that the white matter microstructure of newborn, preterm children is compromised in a regionally specific manner. However, until now it was not clear whether these lesions would persist and be detectible on long-term follow-up. Hence, we collected diffusion tensor imaging data on a 1.5-T scanner, and computed fractional anisotropy and coherence measures to compare the white matter integrity of children born preterm to that of control subjects. The subjects for the preterm group (10.9 ± 0.29 y; n = 9; birth weight ≤ 1500 g; mean gestational age, 28.6 ± 1.05 wk) possessed attention deficits, a common problem in preterms. They were compared with age- and sex-matched control children (10.8 ± 0.33 y; n = 10; birth weight ≥ 2500; gestational age, ≥ 37 wk). We found that the preterm group had lower fractional anisotropy values in the posterior corpus callosum and bilaterally in the internal capsules. In the posterior corpus callosum this difference in fractional anisotropy values may partially be related to a difference in white matter volume between the groups. An analysis of the coherence measure failed to indicate a group difference in the axonal organization. These results are in agreement with previous diffusion tensor imaging findings in newborn preterm children, and indicate that ex-preterm children with attention deficits have white matter disturbances that are not compensated for or repaired before 11 y of age.

Visual impairment in preterm children with periventricular leukomalacia--visual, cognitive and neuropaediatric characteristics related to cerebral imaging.

Thirteen preterm children, aged 4 to 14 years, with visual impairment due to periventricular leukomalacia (PVL) were evaluated for visual function, intellectual level, cognitive profile and motor function. Their visual impairment was characterized by low acuity, crowding, visual field defects and ocular motility disturbances. Their cognitive profile was uneven, often with considerably higher scores on verbal than on visual‐spatial tasks. Nine children had normal intelligence, three had mild mental retardation and one had severe mental retardation. In all the children, visual impairment was complicated by visual perceptual difficulties, accounting for their greater visual handicap than would be expected from their visual acuities and strabismus alone. Though CT or MRI revealed bilateral PVL in all the children, six had no motor impairment consistent with cerebral palsy, which is an unexpected finding.

PERMANENT CORTICAL VISUAL IMPAIRMENT IN CHILDREN

Fifty patients with permanent cortical visual impairment were evaluated. They had a characteristic behaviour profile, usually with residual sight but poor visual attention. 30 of the 50 also had damage to the anterior visual pathway. Visual evoked potential mapping was shown to have a clear advantage over visual evoked responses, and using that in conjunction with CT and clinical data enabled several subgroups of cortical visual impairment to be identified. The diagnosis probably is more common than previously recognised, and should be suspected when there is greater delay in visual development in other areas and the degree of visual loss is unexplained by ocular findings. Using traditional criteria for cortical blindness may mean that many children are not diagnosed, which has serious implications for their rehabilitation.

Prospective study of computed tomography in acute bacterial meningitis

We performed serial CT scans at the time of admission and discharge, and again after 6 to 18 months, in children older than 2 months of age with bacterial meningitis. During the 2-year study period, 60 patients with bacterial meningitis were admitted to British Columbias Childrens Hospital. Forty-one were included in the study, two of whom died soon after admission. The infecting organism was Haemophilus influenzae in 29, Neisseria meningitidis in six, and Streptococcus pneumoniae in six. Abnormalities on the first two CT scans included subdural effusion in eight patients, focal infarction in five, and pus in the basal cisterns in one. All patients with focal infarction or cisternal pus had hemiparesis. Marked cerebral edema was seen in the two patients who died. Transient mild dilation of the subarachnoid space was a common finding; the size of the ventricles or subarachnoid space was increased on the second scan in 29 of 36 patients, and decreased to normal on the third scan in 30 of 33 patients. Clinical management was not influenced by the CT findings, which failed to reveal any clinically significant abnormalities that were not suspected on neurologic examination.

Nystagmus in periventricular leucomalacia

BACKGROUND/AIMS Periventricular leucomalacia (PVL) is a lesion in the immature brain involving the optic radiation. Children with PVL have visual problems including crowding, visual field defects, strabismus, and visual perceptual/cognitive deficits, together with nystagmus. They often have optic nerve hypoplasia seen either as small discs or as large cupping of normal sized optic discs. This study aimed to perform eye movement recordings in a group of children with PVL in order to characterise and classify the nystagmus. METHODS 19 children with PVL on cerebral imaging underwent eye movement recordings with the Ober-2 infrared reflection technique. RESULTS 16 of the 19 subjects had horizontal nystagmus. CONCLUSION The present study shows that nystagmus is commonly seen in children with PVL.

Optic disc morphology may reveal timing of insult in children with periventricular leucomalacia and/or periventricular haemorrhage

Aims: To evaluate the relation between optic disc morphology and timing of periventricular white matter damage, defined as either periventricular leucomalacia (PVL) or periventricular haemorrhage (PVH), as estimated by neuroradiology. Methods: 35 children with periventricular white matter damage who had had neuroradiology performed and ocular fundus photographs taken had their photographs analysed by digital image analysis and compared with a control group of 100 healthy full term children. Timing of brain lesion was estimated by analysis of the brain lesion pattern on neuroradiological examinations (magnetic resonance imaging or computed tomography). Results: Four of 35 children had a small optic disc area; these four children had a brain lesion estimated to have occurred before 28 weeks of gestation. Nine of 11 children with a large cup area had a PVL/PVH estimated to have occurred after 28 weeks of gestation. The children with PVL/PVH had a significantly larger cup area (median 0.75 mm2) than the control group (median 0.33 mm2) (p = 0.001) and a significantly smaller neuroretinal rim area (median 1.58 mm2) than the controls (median 2.07 mm2) (p = 0.001). Conclusion: In a child with PVL/PVH and abnormal optic disc morphology, the possibilities of timing of the lesion should be considered.

Computed Tomography Of The Brains Of Children With Cortical Visual Impairment

Computed tomography (CT) of the brains of 70 children with permanent cortical visual impairment (CVI) and of 25 children who recovered from their cortical visual loss were analysed and the findings were correlated with clinical signs and symptoms. The 70 children with CVI were divided into groups depending on the known or suspected pathophysiology of CVI. Asphyxia caused permanent CVI in 34 children, of whom 16 were preterm, 17 were term and one lost vision later in life. Congenital brain malformations were the second largest group, followed by trauma, infections and shunt failure. 25 children recovered their visual acuities, but six of them were left with homonymous hemianopia. The results identified various clinical characteristics of the groups. CT scanning was helpful in understanding the pathophysiology of CVI, and provided useful information for the prognosis of visual recovery.

Primary Ewing's Sarcoma of the Base of the Skull

The authors report a case of primary Ewings sarcoma of the petrous bone. The radiological features, including the computed tomographic scan and angiographic findings, are described in detail.

Morphology of cerebral lesions in children with congenital hemiplegia

SummaryThis study has analysed the results of CT scans of the brains in children with congenital hemiplegia. The material consists of 111 out of a total of 151 children with this cerebral palsy syndrome in a population-based series. We have classified the morphological findings in five groups. The groups are designed to reflect the phase of maturation of the brain when the insult happened. The groups are: 1. Maldevelopment, 2. Periventricular atrophy, 3. Cortical-/subcortical atrophy, 4. Miscellaneous, 5. Normal. In contrast to previous reports we found a high proportion (17%) with maldevelopment. However the dominating morphological pattern was periventricular atrophy, consistent with a hypoxic-ischemic insult to the immature brain, seen in 42%. Cortical and/or subcortical atrophy was found in 12%. Three children (3%) presented with morphological patterns not possible to classify. The group with no pathology according to CT was 26%.

Visual and cerebral sequelae of very low birth weight in adolescents

Objective: To describe the visual functions and relate them to MRI findings and the intellectual level in adolescents born with very low birth weight (VLBW). Design: Population-based case–control study. Patients: 59 15-year-old VLBW adolescents and 55 sex and age-matched controls with normal birth weight. Main outcome measures: Objective clinical findings (visual acuity, stereo acuity and cycloplegic refraction) were recorded. Structured history taking was used to identify visual difficulties. The intellectual level was assessed with the Wechsler Intelligence Scale for Children (WISC). All VLBW adolescents underwent MRI of the brain. Results: Significant differences were found between the VLBW adolescents and controls regarding visual acuity (median −0.11 and −0.2, respectively; p = 0.004), stereo acuity (median 60″ and 30″, respectively; p<0.001), prevalence of astigmatism (11/58 and 0/55, respectively; p<0.001) and in full-scale IQ (mean IQ 85 and 97, respectively; p<0.001) and performance IQ (mean 87 and 99, respectively; p = 0.002). The structured history also revealed a borderline significant difference between the groups (mean problems 0.46 and 0.15 respectively; p = 0.051). 30% (17/57) of the VLBW adolescents had abnormal MRI findings and performed worse in all tests, compared with both the VLBW adolescents without MRI pathology and the normal controls. Conclusion: This study confirms previous observations that VLBW adolescents are at a disadvantage regarding visual outcome compared with those with normal birth weight. In 47%, visual dysfunction was associated with abnormal MRI findings and in 33% with learning disabilities. The adolescents with abnormal MRI findings had more pronounced visual and cognitive dysfunction. The findings indicate a cerebral causative component for the visual dysfunction seen in the present study.