Visual-perceptual impairment in children with periventricular leukomalacia

Regional vulnerability of longitudinal cortical association connectivity: Associated with structural network topology alterations in preterm children with cerebral palsy

Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL), are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI) studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4) and 75 healthy controls (mean age 5.7 ± 3.4). Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS) and voxel-based morphometry (VBM) demonstrating diffusely reduced fractional anisotropy (FA) reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1) reduced regional posterior-anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation) correlated with reduced posterior-anterior gradient of intra-regional (nodal efficiency) metrics with relative sparing of frontal and temporal regions; and (2) reduced regional FA within frontal-thalamic-striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract) correlated with alteration in eigenvector centrality, clustering coefficient (inter-regional) and participation co-efficient (inter-modular) alterations of frontal-striatal and fronto-limbic nodes suggesting re-organization of these pathways. Both along tract and structural topology network measurements correlated strongly with motor and visual clinical outcome scores. This study shows the value of combining along-tract analysis and structural network topology in depicting not only selective parietal occipital regional vulnerability but also reorganization of frontal-striatal and frontal-limbic pathways in preterm children with cerebral palsy. These finding also support the concept that widespread, but selective posterior-anterior neural network connectivity alterations in preterm children with cerebral palsy likely contribute to the pathogenesis of neurosensory and cognitive impairment in this group.

Visual-perceptual impairment in children with cerebral palsy: a systematic review

AIM

Visual perception is one of the cognitive functions often impaired in children with cerebral palsy (CP). The aim of this systematic literature review was to assess the frequency of visual-perceptual impairment (VPI) and its relationship with patient characteristics.

METHOD

Eligible studies were relevant papers assessing visual perception with five common standardized assessment instruments in children with CP published from January 1990 to August 2011.

RESULTS

Of the 84 studies selected, 15 were retained. In children with CP, the proportion of VPI ranged from 40% to 50% and the mean visual perception quotient from 70 to 90. None of the studies reported a significant influence of CP subtype, IQ level, side of motor impairment, neuro-ophthalmological outcomes, or seizures. The severity of neuroradiological lesions seemed associated with VPI. The influence of prematurity was controversial, but a lower gestational age was more often associated with lower visual motor skills than with decreased visual-perceptual abilities.

INTERPRETATION

The impairment of visual perception in children with CP should be considered a core disorder within the CP syndrome. Further research, including a more systematic approach to neuropsychological testing, is needed to explore the specific impact of CP subgroups and of neuroradiological features on visual-perceptual development.

Delayed finger tapping and cognitive responses in preterm-born male teenagers with mild spastic diplegia

BACKGROUND

Information on fine motor and basic cognitive functions in spastic diplegia is sparse in the literature. The aim of this study was to investigate index finger's tapping speed and cognitive functions in categorization and old/new recognition of pictures in patients with mild spastic diplegia.

METHODS

Fifteen preterm-born male teenagers with mild spastic diplegia and 15 healthy male teenagers participated in this study. Finger-tapping tests and cognitive tests were performed on all participants. Outcomes were compared between the two groups.

RESULTS

In the finger-tapping tests, the tapping speed was significantly slower in patients than in controls. In the tests of tapping one key persistently and tapping two keys alternately, the reaction time gaps between the left and right digits were larger in patients than in controls. In the categorization tests, the accuracies and reaction times for animal/plant and girl face pictures, but not for boy face pictures, were significantly worse in patients than in controls. In the recognition tests, the accuracies for old/new, animal/plant, and boy/girl face pictures were significantly lower in patients than in controls. The reaction times for old/new, animal/plant, and new face pictures, but not for old face pictures, were significantly longer in patients compared with controls.

CONCLUSIONS

Our results demonstrate delayed finger tapping and cognitive responses in preterm-born male teenagers with mild spastic diplegia. Our experimental paradigm is sensitive for the study of fine motor and cognitive functions between patients and healthy controls.

Long-term effects of neonatal hypoxia-ischemia on structural and physiological integrity of the eye and visual pathway by multimodal MRI

PURPOSE

Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways.

METHODS

Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner.

RESULTS

Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres.

CONCLUSIONS

High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury.

Neuropsychological profiles of patients with 2q37.3 deletion associated with developmental dyspraxia

Patients with 2q37 deletions manifest brachydactyly mental retardation syndrome (BDMR). Recent advances in human molecular research have revealed that alterations in the histone deacetylase 4 gene (HDAC4) are responsible for the clinical manifestations of BDMR. Here, we report two male patients with 2q37.3 deletions. One of the patients showed a typical BDMR phenotype, and HDAC4 was included in the deletion region. HDAC4 was preserved in the other patient, and he showed a normal intelligence level with the delayed learning of complex motor skills. Detailed neuropsychological examinations revealed similar neuropsychological profiles in these two patients (visuo-spatial dyspraxia) that suggested developmental dyspraxia. These observations suggested that some other candidate genes for neuronal development exist in the telomeric region of HDAC4.

Developmental coordination disorders: state of art

In the literature, descriptions of children with motor coordination difficulties and clumsy movements have been discussed since the early 1900s. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), it is a marked impairment in the development of fine or global motor coordination, affecting 6% of school-age children. All these children are characterized for developmental coordination disorder (DCD) in motor learning and new motor skill acquisition, in contrast to adult apraxia which is a disorder in the execution of already learned movements. No consensus has been established about etiology of DCD. Intragroup approach through factor and cluster analysis highlights that motor impairment in DCD children varies both in severity and nature. Indeed, most studies have used screening measures of performance on some developmental milestones derived from global motor tests. A few studies have investigated different functions together with standardized assessments, such as neuromuscular tone and soft signs, qualitative and quantitative measures related to gross and fine motor coordination and the specific difficulties -academic, language, gnosic, visual motor/visual-perceptual, and attentional/executive- n order to allow a better identification of DCD subtypes with diagnostic criteria and to provide an understanding of the mechanisms and of the cerebral involvement.

Limitations on the developing preterm brain: impact of periventricular white matter lesions on brain connectivity and cognition

Brain lesions to the white matter in peritrigonal regions, periventricular leukomalacia, in children who were born prematurely represent an important model for studying limitations on brain development. The lesional pattern is of early origin and bilateral, that constrains the compensatory potential of the brain. We suggest that (i) topography and severity of periventricular lesions may have a long-term predictive value for cognitive and social capabilities in preterm birth survivors; and (ii) periventricular lesions may impact cognitive and social functions by affecting brain connectivity, and thereby, the dissociable neural networks underpinning these functions. A further pathway to explore is the relationship between cerebral palsy and cognitive outcome. Restrictions caused by motor disability may affect active exploration of surrounding and social participation that may in turn differentially impinge on cognitive development and social cognition. As an outline for future research, we underscore sex differences, as the sex of a preterm newborn may shape the mechanisms by which the developing brain is affected.

DTI correlates of cognition in term children with spastic diplegic cerebral palsy

BACKGROUND AND AIMS

Presently, there is no published study that shows association between cognition and white matter injury in spastic cerebral palsy. We aimed to correlate cognitive functions with diffusion tensor imaging derived metrics in spastic diplegic children.

METHODS

Twenty-two term children with spastic diplegia and 22 healthy controls were recruited. All patients were graded on the basis of gross motor function. The Indian children intelligence Test was used to quantify cognition and diffusion tensor imaging was used to quantify microstructural changes in various white matter regions. Diffusion tensor imaging metrics were quantified by placing regions of interests in different white matter regions like corona radiata, anterior limb of internal capsule, posterior limb of internal capsule, mid brain, pons, medulla, genu, splenium, temporal white matter, parietal white matter, frontal white matter and occipital white matter.

RESULTS

Spastic diplegic children showed significantly lower neuropsychological test scores as compared to controls. A significantly decreased fractional anisotropy values were observed in corona radiata, anterior limb of internal capsule, posterior limb of internal capsule, mid brain, pons, medulla, genu, splenium and occipital white matter; however significantly increased mean diffusivity values were observed in corona radiata, anterior limb of internal capsule, posterior limb of internal capsule, mid brain, pons and genu in spastic diplegic as compared to controls. A significant positive correlation in fractional anisotropy and negative correlation in mean diffusivity was observed with neuropsychological test scores.

CONCLUSION

These results suggest that these imaging metrics may be used as a biomarker of cognitive functions in term children with spastic diplegia.

Emotional and behavioural problems in children with visual impairment, intellectual and multiple disabilities

BACKGROUND

Children with multiple impairments have more complex developmental problems than children with a single impairment.

METHOD

We compared children, aged 4 to 11 years, with intellectual disability (ID) and visual impairment to children with single ID, single visual impairment and typical development on 'Child Behavior Check List/4-18' (CBCL/4-18), Parent Report.

RESULTS

Children with ID and visual impairment had more emotional and behavioural problems than other groups of children: with single impairment and with typical development (F = 23.81; d.f.1/d.f.2 = 3/156; P < 0.001). All children with special needs had more emotional and behavioural problems than children with typical development. The highest difference was found in attention problems syndrome (F = 30.45; d.f.1/d.f.2 = 3/156; P < 0.001) where all groups of children with impairments had more problems. Children with visual impairment, with and without ID, had more somatic complaints than children with normal vision.

CONCLUSION

Intellectual disability had greater influence on prevalence and kind of emotional and behavioural problems in children than visual impairment.

Visual perceptual strengths and weaknesses in adults with intellectual disabilities compared with a birth year-matched norm

BACKGROUND

The ventral and dorsal streams are considered to be the brain substrates of vision for perception and action, respectively. Using the Developmental Test of Visual Perception (DTVP), the current study examined whether visual perceptual strengths and weaknesses in adults with intellectual disabilities (ID) were attributable to the dichotomy of the visual streams.

METHOD

In study 1, DTVP performance was compared among mild, moderate and severe adult ID groups; study 2 contrasted adult ID groups with and without Down syndrome (DS). To prevent possible contamination by the Flynn effect, participants were matched by birth year with the norm of the DTVP original edition.

RESULTS

Independent of the extent of ID among the three groups in study 1 and the aetiological group difference in study 2, relative strength was found for two DTVP tasks: eye-hand coordination and distinguishing target figures from interference background. Relative weakness was obtained in identifying a figural category. Participants with DS demonstrated exceptional weakness in discerning a target from either mirror-imaged or rotated alternatives, in addition to figural-category detection.

CONCLUSIONS

Visual perceptual strengths and weaknesses in persons with ID were difficult to explain on the basis of two visual streams. An interpretation originating in a different research context (e.g. frontal-lobe dysfunction) appears to be required for explaining visual perceptual weaknesses in persons with ID. For persons with DS, strong frontal-lobe dysfunction with atypical lateralisation might be the pathological determinant of visual perceptual weaknesses.

A test revealing the slow acquisition and the dorsal stream substrate of visuo-spatial perception

We propose a battery of simple clinical tests to assess the development of elementary visuo-spatial perception. We postulate that most of the tasks we selected rely on the visual dorsal stream, although the dual-stream theory (Milner & Goodale, 1995) discards the role of the dorsal stream for visual perception. In order to test the contribution of this anatomical substrate in visuo-spatial perception, we evaluated the performance of two adult patients with acquired bilateral occipito-parietal (dorsal stream) damage. Additionally, the developmental evolution was assessed by testing 96 children from 4 to 12 years old (4 two-year age groups of 24 children). In order to determine the point at which children achieved adult performance, and to provide a control group for the two patients, we also tested a group of 14 healthy adults. The results highlighted the necessity for age-dependent normative values: adult performance was achieved only at the age of 8 for length and size comparisons and at 12 for dot localisation. In contrast, the ability to judge angles and midlines did not reach adult performance even in the oldest group of children, suggesting further acquisition through adolescence. Occipito-parietal lesions strongly and differentially affected elementary visuo-spatial tasks. In overall scores, the two adult patients were approximately at the level of 6-year olds, below the outlier limit of the adult group. They were on average within the adult interquartile range for processing length and size but clearly outside for the 4 other subtests (Angle, Midline, Position perception and Position selection). As a whole, these data both shed light on the neuroanatomical bases of visuo-spatial perception and allow for age-specific comparisons in children with developmental disorders potentially linked to visuo-spatial and/or attentional defects.

Potential of diffusion tensor MR imaging in the assessment of cognitive impairments in children with periventricular leukomalacia born preterm

PURPOSE

To investigate MR diffusion tensor imaging (DTI) and fiber tractography (FT) in the assessment of altered major white matter fibers correlated with cognitive functions in preterm infants with periventricular leukomalacia (PVL), to explore the neural foundation for PVL children's cognitive impairments.

MATERIALS AND METHODS

Forty six preterm infants (16 ± 4.7 months) suffered from PVL and 16 age-matched normal controls were recruited. Developmental quotient (DQ) was recorded to evaluate PVL children's cognitive functions. According to the DQ scores, patients were divided into three groups: mild, moderate and severe cognitive impairment groups. DTI scan was performed. Fractional anisotropy (FA) values of major white matter fibers were measured and their correlation with cognitive levels was evaluated.

RESULTS

Compared with the control group, the PVL group showed a significant mean FA reduction in bilateral corticospinal tract (CST), anterior/posterior limb of internal capsule (ICAL/ICPL), arcuate fasciculus (AF), corona radiate (CR), superior longitudinal fasciculus (SLF), splenium of corpus callosum (SCC) (p<0.05) and bilateral posterior thalamic radiation (PTR) (p<0.01). The FA values of left CST, bilateral AF, anterior cingulum (ACG), SLF, ICAL, ICPL, PTR, CR, genu of corpus callosum (GCC), SCC and middle cerebellar peduncle showed significant negative correlations with the cognitive levels.

CONCLUSIONS

DTI can provide more information for understanding the pathophysiology of cognitive impairment in preterm infants with PVL.

Uniplanar Nystagmus Associated with Perceptual and Cognitive Visual Dysfunction due to Presumed Focal Ischemic Occipital Cortical Atrophy: A Missed Diagnosis and New Observation

Uniplanar nystagmus has been described in relation to pathology of the brain stem, retina, optic nerve, sensory visual deprivation, periventricular leucomalacia, and drug toxicity. This paper describes a case of uniplanar nystagmus associated with features of higher visual dysfunction and a presumed focal insult to the occipital lobes following an episode of neonatal apnea.

My Voice Heard: The Journey of a Young Man with a Cerebral Visual Impairment

This longitudinal case study presents John's journey through childhood and adolescence, living with visual difficulties associated with a cerebral visual impairment. It highlights the day-to-day problems that John encountered, giving practical solutions and strategies that have enabled his dream of going to a university to be realized. John and his family are an inspiration.

Integrity of the inferior longitudinal fasciculus and impaired object recognition in children: a diffusion tensor imaging study

AIM

  In this study, we explored the integrity of the inferior longitudinal fasciculus (ILF) by means of diffusion tensor imaging tractography in children with visual perceptual impairment, and more specifically, object recognition deficits, compared with typically developing children.

METHODS

  Eleven individuals (nine males, two females; mean age 7 y 8 mo; range 3 y 5 mo-13 y) were assessed with the L94 visual perceptual battery after assessment of performance age. In all participants, an ophthalmological evaluation was carried out. Diffusion tensor imaging tractography of the ILF was performed. The mean fractional anisotropy was determined for every child and compared with data for 11 age- and sex-matched typically developing children.

RESULTS

  The mean fractional anisotropy value in the left ILF was consistently lower in the study participants than in the comparison group. The five children with L94 impairment showed a significantly lower ILF fractional anisotropy on the left as well as on the right side. Furthermore, the decrease in ILF fractional anisotropy was correlated with the number of impaired subtests.

INTERPRETATION

The results suggest an association between ILF integrity loss and object recognition deficits. Moreover, the severity of clinical impairment is reflected in the degree of ILF integrity loss. Therefore, the ILF plays a potential role in object recognition.

Visual assessment in children with cerebral palsy: implementation of a functional questionnaire

AIM

The aim of this study was to evaluate an interdisciplinary visual assessment for multiply challenged children diagnosed with cerebral palsy (CP).

METHOD

A comprehensive ophthalmological assessment together with a visual classification scale (VCS) and a questionnaire evaluating daily visual function were completed regarding 77 children (41 females, 36 males; age range 3-20y; mean age 8 y 3 mo [SD 4 y 3 mo]; Gross Motor Function Classification System [GMFCS] level V; Manual Ability Classification System level V) who were diagnosed with CP (79.2% spastic quadriplegia, 6.5% athetoid quadriplegia, 10.4% mixed type, 3.9% hemiplegia). All participants had severe to profound motor and intellectual disability and an inability to communicate consistently through either verbal or assisted communication. The interrater and test-retest reliability of the questionnaire and its validity in comparison with the VCS were examined. In addition, the contribution of ophthalmological testing in predicting daily visual function was assessed.

RESULTS

The ophthalmological examination revealed three diagnostic subgroups: a group with cerebral visual impairment (CVI), a group with optic atrophy, and a group without visual impairment. The questionnaire was found to have high values of interrater reliability (interclass correlation coefficient [ICC]=0.873; 95% confidence interval [CI] 0.762-0.935) and test-retest reliability (ICC=0.988; 95% CI 0.964-0.996). Validity was established for the questionnaire factors: task-orientated visual function (r=0.802; 95% CI 0.669-0.885) and basic visual skills (r=0.691; 95% CI 0.504-0.816). The questionnaire provided information about daily visual performance not available from one-time ophthalmological testing, particularly for participants diagnosed with CVI. The visual performance scale significantly predicted daily visual function for all groups.

INTERPRETATION

This study highlights the benefits of implementing a diagnostic performance scale as well as a reliable functional questionnaire to achieve a precise visual assessment of children with severe neurological impairment.

Visual perceptual difficulties and under-achievement at school in a large community-based sample of children

INTRODUCTION

Difficulties with visual perception (VP) are often described in children with neurological or developmental problems. However, there are few data regarding the range of visual perceptual abilities in populations of normal children, or on the impact of these abilities on children's day-to-day functioning.

METHODS

Data were obtained for 4512 participants in an ongoing birth cohort study (Avon Longitudinal Study of Parents and Children; ALSPAC). The children's mothers responded to questions designed to elicit indications of visual perceptual difficulties or immaturity, when their children were aged 13 years. We examined associations with standardised school test results in reading and in mathematics at age 13-14 years (SATS-KS3), accounting for potential confounders including IQ.

RESULTS

Three underlying factors explained half the variance in the VP question responses. These correlated best with questions on interpreting cluttered scenes; guidance of movement and face recognition. The adjusted parameter estimates (95% CI) for the cluttered-scenes factor (0.05; 0.02 to 0.08; p<0.001) suggested positive associations with the reading test results whilst that for the guidance-of-movement factor (0.03; 0.00 to 0.06; p = 0.026) suggested positive association with the mathematics results. The raw scores were associated with both test results.

DISCUSSION

VP abilities were widely distributed in this sample of 13-year old children. Lower levels of VP function were associated with under-achievement in reading and in mathematics. Simple interventions can help children with VP difficulties, so research is needed into practicable, cost-effective strategies for identification and assessment, so that support can be targeted appropriately.

Cognitive visual dysfunctions in preterm children with periventricular leukomalacia

AIM

Cognitive visual dysfunctions (CVDs) reflect an impairment of the capacity to process visual information. The question of whether CVDs might be classifiable according to the nature and distribution of the underlying brain damage is an intriguing one in child neuropsychology.

METHOD

We studied 22 children born preterm (12 males, 10 females; mean age at examination 8y, range 6-15y; mean gestational age 30wks, range 28-36wks) with periventricular leukomalacia, spastic diplegia, normal intelligence (mean Full-scale IQ 84; mean Verbal IQ 97; mean Performance IQ 74), and normal visual acuity, focusing on higher visual functions. Brain magnetic resonance images (MRI) were analysed to establish the presence of lesions along the primary optic pathway, in the occipitoparietal and occipitotemporal regions.

RESULTS

Most children displayed an uneven cognitive profile, with deficits in visual object recognition, visual imagery, visual-spatial skills, and visual memory, and sparing of visual associative abilities, non-verbal intelligence, and face and letter recognition. Conventional brain MRI did not document major alterations of parietal and temporal white matter, or cortical alteration of areas involved in visual associative functions.

INTERPRETATION

We suggest a widespread involvement of higher visual processing systems, involving both the ventral and dorsal streams, in preterm children with periventricular leukomalacia. The lack of major alterations on conventional MRI does not exclude the possibility of malfunctioning of higher visual processing systems, expressing itself through discrete CVDs. Possible mechanisms underlying these neuropsychological deficits are discussed.

Motor function in 5-year-old children with cerebral palsy in the South Australian population

The aim of this study was to describe the motor function of a population of children at age 5 years enrolled on the South Australian Cerebral Palsy Register. Among children born between 1993 and 1998, there were 333 with confirmed cerebral palsy (prevalence rate 2.2 per 1000 live births), in whom 247 assessments (56.7% males, 43.3% females) were completed. The distribution by Gross Motor Function Classification System (GMFCS) level was: level I, 50.6%; level II, 18.2%; level III, 9.3%; level IV, 9.7%; level V, 12.1%. The most common topographical classification was spastic diplegia (38.5%), followed by spastic hemiplegia (34.8%) and spastic quadriplegia (14.6%). Abnormal movements occurred at rest or with intention in 19.4% of children. A high proportion of the population with relatively mild gross motor impairments have difficulty with everyday bimanual tasks, reinforcing the need to assess upper limb function independently of gross motor function. The use of ankle-foot orthoses was common, particularly across GMFCS levels II to IV. Further refinement is indicated for this population's motor dataset, to include more recently described classification measures as well as future novel measures to better describe the presence of both spasticity and dystonia.

Neurocognitive test profiles of extremely low birth weight five-year-old children differ according to neuromotor status

The neurocognitive outcome of children born with extremely low birth weight (ELBW) is highly variable due to the complexity of morbidity. So far, no study has compared comprehensive neuropsychological test profiles in groups with different neuromotor status. In a national cohort of ELBW children neuropsychological test profiles were assessed in 4 groups defined according to a neurological examination at 5 years of age: normal neuromotor status (N = 56), motor coordination problems (N = 32), multiple subtle neuromotor signs including both motor coordination problems and deviant reflexes (N = 20), and spastic diplegia (N = 12). The neurocognitive assessment included a test of intelligence, the Wechsler Primary and Preschool Scale of Intelligence-Revised (WPPSI-R) and 14 subtests of attention and executive functions, verbal functions, manual motor functions, visuoconstructional functions and verbal learning (NEPSY). The children with normal neuromotor status performed within the average range; children with motor coordination problems had widespread impairment; and children with spastic diplegia and children with multiple minor neuromotor signs had uneven test profiles with stronger verbal results but weaknesses in attention and executive functions, and in manual motor and visuoconstructional tasks. In conclusion, very preterm children with neuromotor signs, including motor coordination problems, are at risk for neurocognitive impairment, in spite of average intelligence. More impaired children have more irregular test profiles. Follow-up and neuropsychological assessment of very preterm children with minor neuromotor signs are therefore indicated.

Assessment of cerebral visual impairment with the L94 visual perceptual battery: clinical value and correlation with MRI findings

In this article we describe visual perceptual abilities of a clinical population, referred for visual problems to our multidisciplinary team and assessed with the five computer tasks from the L94 visual perceptual battery. Clinical and neuroimaging findings were correlated with the findings on this task battery. Seventy children (35 males, 35 females) constituted our cohort. Age ranged from 4 to 20 years (mean 7y [SD 3y]). Forty children were born before 37 weeks gestational age. Thirty-six children had cerebral palsy (CP), of whom 24 had spastic diplegia, five had spastic hemiplegia, and four had spastic quadriplegia. Three children had ataxic CP. Perceptual visual impairment (PVI) was established in comparison to the performance age obtained on non-verbal intelligence subtests, instead of chronological age. Our results suggest that children with a history of preterm birth and a clinical CP picture are most at risk for a specific PVI. Correlations among other clinical variables did not define a clinical subgroup more at risk. Children with periventricular leucomalacia were almost equally represented in both PVI and non-PVI groups. Normal magnetic resonance imaging did not exclude the presence of PVI. In these children, however, we found another impairment profile, more in favour of dorsal stream impairment.

Do visual impairments affect risk of motor problems in preterm and term low birth weight adolescents?

BACKGROUND

Increased prevalence of motor and visual problems has been reported in low birth weight populations, but the association between them is less studied.

AIM

To examine how visual impairments may be associated with the increased risk of motor problems in low birth weight adolescents.

METHODS

Fifty-one very low birth weight adolescents (VLBW), 56 term small for gestational age (SGA) and 75 term control adolescents, without cerebral palsy, were examined at the age of 14. Motor skills were examined by the Movement Assessment Battery for Children. Visual functions included visual acuity, contrast sensitivity, nystagmus, strabismus, stereoacuity, accommodation, convergence and visual perception (Visual-Motor Integration test). An abnormality score was calculated as the sum of visual impairments. We used odds ratio as an estimate of the relative risk of having motor problems.

RESULTS

The odds of having motor problems were 10.4 (95% CI: 2.2-49.4) in the VLBW group and 5.1 (95% CI: 1.0-25.8) in the SGA group compared with the control group. The odds of having motor problems in the VLBW group were influenced by all visual variables, and most by visual acuity, when we adjusted for these separately. The greatest reduction in OR was found when adjusting for the abnormality score (adjusted OR: 6.8; 95% CI: 1.3-34.5). In the SGA group the odds of having motor problems were relatively unaffected by the visual variables and the abnormality score.

CONCLUSIONS

Visual impairments influence motor problems in VLBW adolescents, whereas motor problems in SGA adolescents seem to be unaffected by visual impairments.

The assessment of visual acuity in children with periventricular damage: a comparison of behavioural and electrophysiological techniques

It has been controversial whether electrophysiology offers better precision than behavioural techniques in measuring visual acuity in children with brain damage. We investigated the concordance between sweep VEPs and Acuity Cards (AC) in 29 children with periventricular leukomalacia (PVL), the most common type of brain damage in preterm infants. An overall good correlation was shown but with relatively better behavioural acuity values. VEP/AC ratio was significantly correlated to corpus callosum posterior thinning. We propose that this result reflects the efficacy of the compensatory mechanisms following early brain damage which may differentially affect the two methods.

White-matter injury is associated with impaired gaze in premature infants

Periventricular leukomalacia is a risk factor for visual impairment in children born prematurely. The impact of diffuse white-matter injury, as detected on magnetic resonance imaging, on early visual function is unknown. We developed two 5-point visual-gaze scores to analyze the association between this clinical assessment and white-matter injury in 93 premature neonates <34 weeks of gestational age at birth. Older postmenstrual age was associated with higher values of the two gaze scores. Infants with moderate or severe white-matter injury had lower scores than their peers without white-matter injury (0.41 points, 95% confidence interval of 0.13-0.69 for visual fixation score; and 0.70 points, 95% confidence interval of 0.30-1.10 for conjugate score, P < 0.005). Using the results from both scales, a score of >or=9 in an infant examined at >or=36 weeks postmenstrual age predicted normal white matter on magnetic resonance examination, with a sensitivity of 84% and a specificity of 100%. These preliminary findings suggest that white-matter injury affects visual function even before term equivalent postmenstrual age.

Leucomalácia periventricular e diplegia espástica: implicações nas habilidades psicolingüísticas

TEMA: a paralisia cerebral espástica do tipo diplégica (PC-D) é freqüentemente relacionada à Leucomalácia Periventricular (LPV), a qual geralmente afeta fibras motoras descendentes do córtex de associação e fibras de associação das funções visuais, auditivas e somestésicas. OBJETIVO: verificar o desempenho de crianças com PC-D quanto às habilidades psicolingüísticas. MÉTODO: participaram deste estudo oito indivíduos de ambos os sexos e idade cronológica variando de quatro a seis anos, diagnosticados como PC-D, confirmadas na ressonância magnética a lesão tipo LPV. Foram avaliados por meio do Teste de Illinois de Habilidades Psicolinguísticas (TIHP), Teste de Vocabulário por Imagens Peabody (TVIP), considerando o desempenho cognitivo, o grau de distúrbio motor e o desempenho nos subtestes auditivos e visuais do TIHP. RESULTADOS: os resultados apontaram correlação significante entre desempenho cognitivo e TVIP e a mesma correlação foi confirmada entre o desempenho do TVIP e o subteste de recepção auditiva do TIHP, considerando a idade psicolingüística. Na comparação entre as habilidades auditivas e visuais, os participantes tiveram melhor desempenho nas atividades que envolviam habilidades visuais, confirmando a correlação significante no subteste de associação. Houve correlação estatisticamente significante entre o grau de distúrbio motor e o desempenho psicolingüístico, confirmando a influência do distúrbio motor nestas atividades. CONCLUSÃO: as crianças com PC-D e sinais sugestivos de LPV apresentaram prejuízo nas habilidades psicolingüísticas, justificando a necessidade de estudos adicionais nesta área com o intuito de conhecer melhor o desenvolvimento destas habilidades.

Cognitive visual impairment with good visual acuity in children with posterior periventricular white matter injury: a series of 7 cases

BACKGROUND

We describe a series of term and preterm children with occipito-parietal periventricular white matter abnormalities on magnetic resonance imaging (MRI) who manifest common clinical features of cognitive visual dysfunction. We also describe a strategy for taking clinical history that highlights the symptom complex and assists with management.

PATIENTS AND METHODS

A retrospective observational case series study of seven children with cognitive visual difficulties despite good (20/32 or better) visual acuities and MRI findings of periventricular white matter pathology in the territory subserving visual function. Structured history taking was used to identify and characterize the visual difficulties. Objective clinical findings (visual acuity, color vision, stereoacuity, visual fields, ocular motility, refraction, and fundoscopy) were recorded.

RESULTS

Seven children with visual acuities of 20/32 (0.200 logMAR) or better had symptoms of cognitive visual difficulties consistent with dorsal stream dysfunction. Four had strabismus of different types and were identified on the basis of parental concern expressed at the ocular motility clinic. The other three children presented to the general ophthalmology clinic. All seven children had various degrees of focal periventricular white matter pathology in a similar distribution on neuroimaging.

CONCLUSIONS

Children born prematurely are susceptible to periventricular white matter pathology. Such pathology can also occur in children born at term. This case series demonstrates that cognitive visual impairment due to periventricular white matter injury can occur despite good central visual function. A range of strategies to help affected children is described.

The development of visual object recognition in school-age children

This study documents the age-dependent development of visual object recognition abilities in 115 children aged 6 to 11 years, using a battery of neuropsychological tests based on Marrs model (Efron test, Warringtons Figure-Ground Test, Street Completion Test, Poppelreuter-Ghent Test, a selection of stimuli from the Birmingham Object Recognition Battery, a series of color photographs of objects presented from unusual perspectives or illuminated in unusual ways). The results suggest a maturation of complex visual perceptual abilities, possibly related to the development of the cerebral processes involved in object recognition, and could be the starting point for future investigations of these skills in impaired populations.

Visual acuity, contrast sensitivity, peripheral vision and refraction in low birthweight teenagers

PURPOSE

To assess visual acuity (VA), contrast sensitivity, visual fields, refractive errors and use of correction in adolescents with very low birthweight (VLBW; birthweight < 1500 g) and adolescents born at term but small for gestational age (SGA; birthweight < 10th percentile) in a population-based study.

METHODS

Ophthalmological examination including VA, Vistech contrast sensitivity and Humphrey two-zone, 120-point perimetry was performed in 51 VLBW, 59 SGA and 77 control adolescents.

RESULTS

The VLBW adolescents had reduced VA, reduced contrast sensitivity, and were more often anisometropic compared with control adolescents. They had started wearing glasses earlier, but were not more likely to use correction as teenagers. However, they were more often undercorrected (for refractive status) than control adolescents. Hypermetropia was more common in the SGA group than in the control group, but otherwise the SGA group did not differ from the control group.

CONCLUSIONS

Being born SGA may be a risk factor for hypermetropia in adolescence. Prematurely born adolescents present lower VA and contrast sensitivity and are more prone to anisometropia than adolescents born at term. It may be noteworthy that a higher proportion of VLBW than control adolescents were undercorrected, despite the well known vulnerability of visual function associated with preterm birth.

Spectrum of visual disorders in children with cerebral visual impairment

Cerebral visual impairment is a visual function deficit caused by damage to the retrogeniculate visual pathways in the absence of any major ocular disease. It is the main visual deficit in children in the developed world. Preperinatal hypoxic-ischemic damage is the most frequent cause of cerebral visual impairment, but the etiology is variable. The authors set out to evaluate the presence of visual disorders not attributable to any major ocular pathology in a sample of children with central nervous system disease and to describe the clinical picture of cerebral visual impairment in this cohort. One hundred twenty-one patients with central nervous system damage and visual impairment underwent a protocol developed at the authors' center that included neurologic, neurophthalmologic, and neuroradiologic assessments (brain magnetic resonance imaging). Reduced visual acuity was found in 105 of 121 patients, reduced contrast sensitivity in 58, abnormal optokinetic nystagmus in 88, and visual field deficit in 7. Fixation was altered in 58 patients, smooth pursuit in 95, and saccadic movements in 41. Strabismus was present in 88 patients, and abnormal ocular movements were found in 43 patients. Of the 27 patients in whom they could be assessed, visual-perceptual abilities were found to be impaired in 24. Fundus oculi abnormalities and refractive errors were frequently associated findings. This study confirms that the clinical expression of cerebral visual impairment can be variable and that, in addition to already well-documented symptoms (such as reduced visual acuity, visual field deficits, reduced contrast sensitivity), the clinical picture can also be characterized by oculomotor or visual-cognitive disorders. Cerebral visual impairment is often associated with ophthalmologic abnormalities, and these should be carefully sought. Early and careful assessment, taking into account both the neurophthalmologic and the ophthalmologic aspects, is essential for a correct diagnosis and the development of personalized rehabilitation programs.

Cognitive profiles and visuoperceptual abilities in preterm and term spastic diplegic children with periventricular leukomalacia

Although relations between the extent of periventricular leukomalacia and neuropsychological performance in preterm children with spastic diplegia have been extensively investigated, studies on term children with spastic diplegia are rare. The authors examined 15 preterm children and 9 term children with spastic diplegia, all of whom had periventricular leukomalacia as a main magnetic resonance imaging (MRI) finding (excluding full-term spastic diplegic children with other MRI findings). Cognitive abilities (Griffith scale) and visuoperceptual abilities (Developmental Test of Visual Perception) were compared in the 2 groups and related to periventricular leukomalacia severity. Cognitive performance was substantially similar in the 2 groups. However, the overall Developmental Test of Visual Perception scores were below normal in the preterm and were normal in the term children; furthermore, visuoperceptual abilities were differentially affected in the preterm children, with visuomotor abilities more compromised than nonmotor visuoperceptual abilities. These children had similar cognitive performance and MRI findings, so the greater visuoperceptual compromise in the preterm group suggests a direct influence of prematurity, which may have adversely influenced the reorganization of visual centers and pathways following the initial developmental insult. The strabismus present in most preterm children would also have contributed to their greater visuoperceptual compromise. The authors conclude that the management of preterm and term children should differ, with concentration on visuoperceptual skills and rehabilitation in the former.

Visual function and visual perception in cerebral palsied children

PURPOSE

To investigate visual function and perception in cerebral palsied (CP) children.

METHODS

A total of 105 congenitally CP children (aged 6-15 years), without severe mental retardation, were classified into three groups: those with spastic quadriplegia, spastic diplegia and spastic hemiplegia. Data collected included patient history, IQ, refraction, far and near visual acuity, position of the eyes and eye movements, visual fields, colour perception, stereoacuity, slit lamp and fundoscopic examinations, and evaluation of visual perception. The results were compared with a control group from the general paediatric population.

RESULTS

The IQ of the CP children ranged between 70 and 100. A total of 59% of them had best corrected distance visual acuity <6/6, with 25.5% <6/9. Near visual acuity was also reduced (70.1% scored <6/6 and 38.4% scored <6/9). Incidence of refractive errors was higher than in the control group (hypermetropia in 43.8% of the eyes, myopia 16.19% and astigmatism 40.9%) as was the incidence of strabismus (26.7% esotropic and 27.6% exotropic). In visual field testing, 80.95% of CP children were normal. A total of 94.28% had normal colour perception and 89.52% were free of ocular pathology. Stereopsis was abnormal or absent in 85.71% of the cases. Visual perception was markedly reduced: in 57.14% of the cases it was less than or equal to that of 6-year-old children; in 26.66% equal to that of 6- to 7.5-year-old children, and in 16.2% of the cases greater than or equal to that of 7.5-year-old children.

CONCLUSIONS

In the absence of severe mental retardation, CP children have deficient visual skills. It is suggested that the poor visual skills of CP children are a separate, identifiable factor compounding the adverse effects of mental retardation.

Potential of diffusion tensor MRI in the assessment of periventricular leukomalacia

AIM

To investigate magnetic resonance (MR) diffusion tensor imaging (DTI) and fibre tractography in the assessment of altered major white matter (WM) fibre tracts in periventricular leukomalacia (PVL).

MATERIALS AND METHODS

Twelve children (male:female = 7:5, age range 3-10 years; mean age = 6.5 years) who had suffered PVL were included in this study. Meanwhile, Twelve age-matched normal controls (male:female = 6:6, age range 4-12 years; mean age = 7.3 years) with normal MRI findings and no neurological abnormalities were recruited for comparison. DTI was performed with 15 different diffusion gradient directions and DTI colour maps were created from fractional anisotropy (FA) values and the three vector elements. To identify alteration of WM fibre tracts in patient of PVL quantitatively, FA values on diffusion tensor colour maps were compared between the patients and controls. Quantitative analysis was performed using the regions of interest (ROI) method settled on the central part of all identifiable WM fibres, including the corticospinal tract (CST) in the brainstem, middle cerebellar peduncle (MCP), medial lemniscus (ML), anterior/posterior limb of internal capsule (ICAL/ICPL), arcuate fasciculus (AF), posterior thalamic radiation (PTR), genu of corpus callosum (GCC), splenium of corpus callosum (SCC), corona radiata (CR), cingulum (CG), and superior longitudinal fasciculus (SLF). The averaged FA value of each WM fibre was measured and summarized as the mean +/- standard deviation (SD). All data were analysed by paired Student's t-test. A p-value of less than 0.05 was considered to indicate statistical significance.

RESULTS

Visual investigation of WM fibre tracts showed that the ICAL, brainstem CST, ML, MCP, and external capsule (EC) was similar in controls and subjects. However, the ICPL, AF, PTR, CR, CG, SLF and corpus callosum, were all attenuated in size. All 12 cases of PVL showed a significant mean FA reduction in the ICPL, AF, PTR, CR, CG, SLF, SCC, and GCC in comparison with the ipsilateral regions of healthy controls (p<0.05). However, there were no statistically significant differences of the ICAL, ML, MCP, and brainstem CST when analysed using a two-tailed Student's t-test for paired data (p>0.01).

CONCLUSION

DTI can provide more information for understanding the pathophysiology of motor disability and associated sensory handicap in PVL.