Early cognitive and communication development in children with focal brain lesions.

Early cognitive and language development of children with congenital focal brain lesions, documented by magnetic resonance imaging, was studied in 18 cases, 9 with left-hemisphere damage and 9 with right-hemisphere damage, at about 2 (Time 1) and 4 years of age (Time 2). All of the children showed normal cognitive development, but their global Griffiths Developmental Scales scores were lower at Time 2, and developmental profiles across individual subscales revealed side-specific effects, resembling the adult left/right cerebral hemisphere lesion model. Expressive lexicon and grammar were delayed, more often in left-hemisphere-damaged than in right-hemisphere-damaged children, at Time 1 and Time 2. Functional findings were not related to the size and location of the brain lesion, whereas the presence of epilepsy was a highly significant predictor of cognitive and language outcome, irrespective of the side of the lesion. The stable disadvantage in the verbal domain shown by left-hemisphere-damaged children within the age range of this study might suggest that the left hemisphere has some initial bias for language learning. The effects of right-hemisphere damage were more variable and emerged at a later stage of language development.

Visual function in children with hemiplegia in the first years of life.

The aim of this study was to evaluate the incidence of visual function abnormalities in children with infantile hemiplegia, and the relation between visual abnormalities and type of lesion, as shown by brain MRI. Visual function was tested (grating acuity, visual field size, binocular optokinetic nystagmus [OKN], and ocular movements) in a group of 47 children with congenital or early acquired hemiplegic cerebral palsy (mean age 25 months, range 8 to 52 months). The cohort was subdivided into four groups according to MRI findings: brain malformations (n=5), abnormalities of the periventricular white matter (n=20), cortical-subcortical lesions (n=16), and non-progressive postnatal brain injuries (n=6). More than 80% of the children showed abnormal results in at least one visual test: acuity was the least impaired function, while visual field and OKN were abnormal in more than 50% of the cohort. No specific correlation could be identified between the type and timing of the lesions and visual function. Unlike adults with stroke, visual field defects were not always related to contralateral damage in the optic radiations or in the visual cortex. These results indicate that visual abnormalities are common in children with hemiplegia, and that they cannot always be predicted by MRI. All children with hemiplegia need a detailed assessment of visual function.

Correlation between visual function, neurodevelopmental outcome, and magnetic resonance imaging findings in infants with periventricular leucomalacia.

AIM: To evaluate the correlation between visual function and neurodevelopmental outcome in children with periventricular leucomalacia at 1 and 3 years. METHOD: Visual acuity, visual field, ocular motility, and optokinetic nystagmus were tested in 29 infants with periventricular leucomalacia by brain magnetic resonance imaging. All infants also had a structured neurological examination and a Griffiths developmental assessment. RESULTS: 21 of the infants showed at least one abnormality of visual function. The degree of visual impairment-that is, the number of visual tests showing abnormal results-correlated well with the results on developmental assessment at both ages. CONCLUSION: Multivariate analysis showed that visual impairment was the most important variable in determining the neurodevelopmental scores of these infants, more than their motor disability and the extent of their lesions on magnetic resonance imaging.

Visual information processing in infants with focal brain lesions.

Visual information processing for faces were tested by means of the Fagan test of infant intelligence (FTII) in six infants of approximately 12 months of age affected by congenital unilateral brain lesions. Magnetic resonance imaging (MRI) was used to determine the side and size of the lesions. In addition to the FTII, all infants were submitted to a psychometric evaluation using the Griffiths scales. Visual acuity, visual field, and ocular motility were also assessed. Three infants showed damage in the left hemisphere and three in the right. The severity of the lesions, as revealed by MRI scan, was similar in the two groups. All infants except one had normal or borderline cognitive scores on the Griffiths scales. Conversely, four infants showed abnormal results on the FTII, which were not associated with the severity of the lesions, psychometric scores, or the presence of visual deficits. A preference for stimuli presented on the left side of the screen was found, independent of the side of the lesions. This effect was stronger for novel stimuli. The results of this study confirm the importance of early assessment of neuropsychological functions in infants with focal brain lesions.

Visual outcome at 5 years of newborn infants at risk of cerebral visual impairment.

Visual development at 5 years of age was tested in a group of 39 children who had shown severe neonatal encephalopathy or perinatal brain lesions, documented by medical history, cranial ultrasound, or MRI. In all children, grating acuity was tested during the first 2 years of life. The assessment protocol at 5 years included various visual functions (grating and resolution acuity, visual field size, depth perception, optokinetic nystagmus, and ocular motility), and neurological and cognitive development. The majority of the children showed visual disorders of different type and degree, which were not due to ophthalmological abnormalities. Visual defects correlated well with the results of early visual assessment and of neuroimaging. Visual outcome could be predicted by grating acuity at 1 to 2 years in 27 of the 39 children, by neonatal cranial ultrasound in 26 of the 32 cases examined by this technique, and by later MRI in 23 out of 27. Moreover, a significant correlation was found between visual, motor, and cognitive impairment.

MRI findings and sensorimotor development in infants with bilateral spastic cerebral palsy.

The correlation between MRI findings and sensorimotor development was investigated in a group of 48 infants with bilateral spastic cerebral palsy (CP). The ages at MRI examination and cognitive assessment were fairly homogeneous (mean 15 months and 17 months, respectively). The following MRI parameters were scored: size of lateral ventricles, extension of white matter lesions and of white matter reduction, thinning of corpus callosum, presence and size of cystic areas, dimension of subarachnoid spaces and presence of cortical abnormalities. Cognitive assessment included Griffiths Developmental Scales and Uzgiris-Hunt Scales. The patients were subdivided into six classes according to intellectual level (DSM-III-R). For the whole group a highly significant correlation was found between all MRI parameters and the level of cognitive development. This result was probably due to the inclusion of 14 untestable, severely mentally retarded infants, who showed very severe MRI abnormalities. However, when the untestable infants were excluded from the analysis, it was the presence of cysts and the entity of white matter reduction that correlated with both Griffiths Scales and Uzgiris-Hunt Scales. These results indicate the clinical value of MRI findings and particularly of white matter abnormalities for early identification of sensorimotor impairment in infants with bilateral spastic CP.

Processing capacity limitations in pictorial and spatial representations in the totally congenitally blind.

The study of visuo-spatial imagery abilities in totally congenitally blind people may be instrumental in understanding the contribution of visual experience to imagery processes. In the present paper visuo-spatial imagery capacity was explored through a task devised by Kerr (1987) and adapted for presentation to the blind, in which subjects were asked to imagine either two- or three-dimensional matrices of different complexity and to follow a mental pathway. The first experiment showed that blind people have difficulty with three-dimensional matrices which are within the reach of sighted people, and that their performance is affected by the processing rate. In the second experiment the spatial and pictorial components of visual imagery were analyzed by way of the same spatial task and of a pictorial-tactual task in which subjects had to match a mental representation of a pathway to a tactually explored wire silhouette. On the latter task, blind people did not meet any particular difficulty, probably because they could form representations using other sensory modalities and because they were skillful in tactual exploration. These data suggest that research on the blind cannot easily contribute to the distinction between the spatial and pictorial components of visual imagery.

Mild iodine deficiency in fetal/neonatal life and neuropsychological performances.

The effects of mild/moderate iodine deficiency during the fetal/neonatal life on neuropsychological performances are still poorly defined. In this research we analyzed some parameters of cognitive performance with sensitive psychometric tests in children living in an area with moderate iodine deficiency. Each subject was submitted to the following neuropsychological tests: 1) a reaction time (RT) session, 2) the block design subtest of the WISC-R, 3) the coding subtest of the WISC-R. No significant difference was found between children with mild iodine deficiency and controls, for block design and coding tests. On the other hand controls had significantly faster RTs. Our data show that exposure to mild iodine deficiency in fetal/neonatal life does not affect general cognitive performance but influences the velocity of motor response to visual stimuli, which may be due to an alteration of the efficiency of the information processing mechanism.