In this follow-up study, 20 of a geographically based year cohort of 31 surviving non-disabled VLBW (birthweight < 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's impression of the child during the examination and based on the parent'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.

Neuronal migration disorders are the result of disturbed brain development. In such disorders, neurons are abnormally located. In diagnosing these conditions, magnetic resonance imaging is superior to any other imaging technique. This enables us to improve our knowledge of the clinical correlates of neuronal migration. With reference to migrational disorder, a retrospective study of all 303 patients with epileptic seizures referred for magnetic resonance imaging during a 3-year period was performed, 13 patients (aged 12-41, mean age 27) were identified. They represent 4.3% of the entire study group. Of the patients with known epilepsy, 6.7% and of the mentally retarded, 13.7% had migrational disorders. Four patients had schizencephaly as the dominant finding, one was classified as hemimegalencephaly, 2 had isolated heterotopias, and 6 had localized pachy- and/or poly-microgyria. The clinical pictures are complex. Ectopias of grey matter are recognised foci of epilepsy, but from an epileptological and a clinical viewpoint little attention has been given to these disorders. The present study shows that malmigration is not rare in epilepsy patients, especially not in the mentally retarded.

Cerebral MRI pathology in white matter is a common finding in VLBW teenagers. The findings may indicate minor perinatal PVL with resulting loss of white-matter tissue and ventricular dilation.

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Thirty-one (77.5%) of a year cohort of 40 surviving infants with birth weight < 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 < 0.001) and on the Psychomotor Index (PDI) (60 versus 94, p < 0.005). Mean PDI score in Group 2 was significantly lower than in Group 1 (74 versus 94, p < 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)