Eye-movement disorders and visual-perceptual impairment in diplegic children born preterm: a clinical evaluation

Visual Function and Neuropsychological Profile in Children with Cerebral Visual Impairment

Cerebral Visual Impairment (CVI) has become the leading cause of children’s visual impairment in developed countries. Since CVI may negatively affect neuropsychomotor development, an early diagnosis and characterization become fundamental to define effective habilitation approaches. To date, there is a lack of standardized diagnostic methods to assess CVI in children, and the role of visual functions in children’s neuropsychological profiles has been poorly investigated. In the present paper, we aim to describe the clinical and neuropsychological profiles and to investigate the possible effects of visual functions on neuropsychological performance of a cohort of children diagnosed with CVI. Fifty-one children with CVI were included in our retrospective analysis (inclusion criteria: verbal IQ > 70 in Wechsler scales; absence of significant ocular involvement). For each participant, we collected data on neuropsychological assessment (i.e., cognitive, cognitive visual, and learning abilities), basic visual functions (e.g., Best Corrected Visual Acuity—BCVA, contrast sensitivity, and ocular motor abilities) and global development features (e.g., neurological signs and motor development delay) based on standardized tests, according to patients’ ages. The results showed that oculomotor dysfunction involving saccades and smooth pursuit may be a core symptom of CVI and might have a significant impact on cognitive visual and other neuropsychological abilities. Furthermore, visual acuity and contrast sensitivity may influence cognitive, cognitive visual, and academic performances. Our findings suggest the importance of a comprehensive assessment of both visual and neuropsychological functions in children when CVI is suspected, which is needed to provide a more comprehensive functional profile and define the best habilitation strategy to sustain functional vision.

Cognitive functioning in children with cerebral palsy

Children with cerebral palsy (CP) have an increased risk of cognitive impairments. This narrative review of the literature discusses assessment of cognition in children with CP, presents the most salient characteristics of cognitive functioning pertaining to each subtype, and discusses the relationships between brain injury, functioning, and intervention from a developmental perspective. A search for original studies of cognitive functioning in children with different subtypes of CP was performed. The search resulted in 81 unique hits. There were few studies with a representative sample of children with CP where all participants were individually assessed. Cognitive functioning in children with the most severe motor impairments were often assumed and not assessed. Furthermore, there was a confounding of IQ below 70 and intellectual disability, possibly leading to an overestimation of the prevalence of intellectual disability. Longitudinal neuropsychological studies, including also very young children and those with the most severe speech and motor impairments, as well as intervention studies, are called for. WHAT THIS PAPER ADDS: Few studies have assessed cognition in a representative sample of children with cerebral palsy. Cognition in children with severe motor impairment is often assumed, not assessed. Lack of assessment may lead to overestimating the prevalence of intellectual disability. Lowered cognitive functioning in older children highlights the need for longitudinal studies.

Impact of Cerebral Visual Impairments on Motor Skills: Implications for Developmental Coordination Disorders

Cerebral visual impairment (CVI) has become the primary cause of visual impairment and blindness in children in industrialized countries. Its prevalence has increased sharply, due to increased survival rates of children who sustain severe neurological conditions during the perinatal period. Improved diagnosis has probably contributed to this increase. As in adults, the nature and severity of CVI in children relate to the cause, location and extent of damage to the brain. In the present paper, we define CVI and how this impacts on visual function. We then define developmental coordination disorder (DCD) and discuss the link between CVI and DCD. The neuroanatomical correlates and aetiologies of DCD are also presented in relationship with CVI as well as the consequences of perinatal asphyxia (PA) and preterm birth on the occurrence and nature of DCD and CVI. This paper underlines why there are both clinical and theoretical reasons to disentangle CVI and DCD, and to categorize the features with more precision. In order to offer the most appropriate rehabilitation, we propose a systematic and rapid evaluation of visual function in at-risk children who have survived preterm birth or PA whether or not they have been diagnosed with cerebral palsy or DCD.

Comparative Study of Refractive Errors, Strabismus, Microsaccades, and Visual Perception Between Preterm and Full-Term Children With Infantile Cerebral Palsy

The purpose of this study was to examine the refractive status, orthoptic status and visual perception in a group of preterm and another of full-term children with cerebral palsy, in order to investigate whether prematurity has an effect on the development of refractive errors and binocular disorders. A hundred school-aged children, 70 preterm and 30 full-term, with congenital cerebral palsy were examined. Differences for hypermetropia, myopia, and emmetropia were not statistically significant between the 2 groups. Astigmatism was significantly increased in the preterm group. The orthoptic status was similar for both groups. Visual perception was markedly reduced in both groups, but the differences were not significant. In conclusion, children with cerebral palsy have impaired visual skills, leading to reading difficulties. The presence of prematurity does not appear to represent an additional risk factor for the development of refractive errors and binocular disorders.

Common visual problems in children with disability

Children with disability are at a substantially higher risk of visual impairment (VI) (10.5% compared with 0.16%) but also of ocular disorders of all types, including refractive errors and strabismus. The aetiology of VI in children with disability reflects that of the general population and includes cerebral VI, optic atrophy, as well as primary visual disorders such as retinal dystrophies and structural eye anomalies. VI and other potentially correctable ocular disorders may not be recognised without careful assessment and are frequently unidentified in children with complex needs. Although assessment may be more challenging than in other children, identifying these potential additional barriers to learning and development may be critical. There is a need to develop clearer guidelines, referral pathways and closer working between all professionals involved in the care of children with disability and visual disorders to improve our focus on the assessment of vision and outcomes for children with disability.

Eye movement during reading in young adults with cerebral palsy measured with eye tracking

BACKGROUND

Cerebral palsy is a nonprogressive brain disorder associated with lifelong motor impairments and often with cognitive deficits, impaired communication, and impaired sensory perception. Vision deficits, in particular, occur frequently in cerebral palsy and can lead to reading difficulties.

OBJECTIVE

Investigate the extent to which the motor impairments in this clinical group affect patients' ability to read.

METHODS

An eye-tracking system was used to record the eye movements during a reading task in 31 adults diagnosed with cerebral palsy and in 10 healthy controls. Participants were asked to read out loud 1 to 5 excerpts from children's books.

RESULTS

In comparison to the healthy readers, cerebral palsy patients took longer to read the excerpts; made more saccades, fixations, and regressions; and made shorter saccades. Average fixation times were similar between the 2 groups, but the average saccade duration was significantly longer for the cerebral palsy group, as a function of the degree of severity of motor impairment. The latter was not a determinant of the level of text comprehension achieved by these patients.

CONCLUSIONS

OBJECTIVE measures of eye movement during a reading task can be obtained in cerebral palsy patients using eye-tracking techniques. RESULTS suggest that cerebral palsied patients may experience difficulties in searching for words during reading.

Rehabilitation outcomes of children with cerebral palsy

[Purpose] To evaluate the results of Bobath-based rehabilitation performed at a pediatric cerebral palsy (CP) inpatient clinic. [Subjects and Methods] The study subjects were 28 children with CP who were inpatients at a pediatric service. Inclusion criteria were: being an inpatient of our hospital aged 2–12 with a diagnosis of CP; having one permanent primary caregiver; and the caregiver having no medical or psychotic problems. All of the patients received Bobath treatment for 1 hour per day, 5 days a week. The locomotor system, neurologic and orthopedic examination, Gross Motor Function Measure (GMFM) of the patients, and Short Form-36 (SF-36) of permanent caregivers were evaluated at the time of admission to hospital, discharge from hospital, and at 1 and 3 months after discharge. [Results] Post-admission scores of GMFM at discharge, and 1 and 3 months later showed significant increase. Social function and emotional role subscores of SF-36 had increased significantly at discharge. [Conclusion] Bobath treatment is promising and randomized controlled further studies are needed for rehabilitation technics.

Visual impairment in children with spastic cerebral palsy measured by psychophysical and electrophysiological grating acuity tests

BACKGROUND

This study measured grating visual acuity in 173 children between 6-48 months of age who had different types of spastic cerebral palsy (CP).

METHOD

Behavioural acuity was measured with the Teller Acuity Cards (TAC) using a staircase psychophysical procedure. Electrophysiological visual acuity was estimated using the sweep VEP (sVEP).

RESULTS

The percentage of children outside the superior tolerance limits was 44 of 63 (69%) and 50 of 55 (91%) of tetraplegic, 36 of 56 (64%) and 42 of 53 (79%) of diplegic, 10 of 48 (21%) and 12 of 40 (30%) of hemiplegic for sVEP and TAC, respectively. For the sVEP, the greater visual acuity deficit found in the tetraplegic group was significantly different from that of the hemiplegic group (p<0.001). In the TAC procedure the mean visual acuity deficits of the tetraplegic and diplegic groups were significantly different from that of hemiplegic group (p<0.001). The differences between sVEP and TAC means of visual acuity difference were statistically significant for the tetraplegic (p<0.001), diplegic (p<0.001), and hemiplegic group (p=0.004).

DISCUSSION

Better visual acuities were obtained in both procedures for hemiplegic children compared to diplegic or tetraplegic. Tetraplegic and diplegic children showed greater discrepancies between the TAC and sVEP results. Inter-ocular acuity difference was more frequent in sVEP measurements.

CONCLUSIONS

Electrophysiologically measured visual acuity is better than behavioural visual acuity in children with CP.

Eye hand coordination in children with cerebral palsy

Reaching to grasp an object of interest requires complex sensorimotor coordination involving eye, head, hand and trunk. While numerous studies have demonstrated deficits in each of these systems individually, little is known about how children with cerebral palsy (CP) coordinate multiple motor systems for functional tasks. Here we used kinematics, remote eye tracking and a trunk support device to examine the functional coupling of the eye, head and hand and the extent to which it was constrained by trunk postural control in 10 children with CP (6-16 years). Eye movements in children with CP were similar to typically developing (TD) peers, while hand movements were significantly slower. Postural support influenced initiation of hand movements in the youngest children (TD & CP) and execution of hand movements in children with CP differentially depending on diagnosis. Across all diagnostic categories, the most robust distinction between TD children and children with CP was in their ability to isolate eye, head and hand movements. Results of this study suggest that deficits in motor coordination for accurate reaching in children with CP may reflect coupled eye, head, and hand movements. We have previously suggested that coupled activation of effectors may be the default output for the CNS during early development.

Inversion of Perceived Direction of Motion Caused by Spatial Undersampling in Two Children with Periventricular Leukomalacia

We report here two cases of two young diplegic patients with cystic periventricular leukomalacia who systematically, and with high sensitivity, perceive translational motion of a random-dot display in the opposite direction. The apparent inversion was specific for translation motion: Rotation and expansion motion were perceived correctly, with normal sensitivity. It was also specific for random-dot patterns, not occurring with gratings. For the one patient that we were able to test extensively, contrast sensitivity for static stimuli was normal, but was very low for direction discrimination at high spatial frequencies and all temporal frequencies. His optokinetic nystagmus movements were normal but he was unable to track a single translating target, indicating a perceptual origin of the tracking deficit. The severe deficit for motion perception was also evident in the seminatural situation of a driving simulation video game. The perceptual deficit for translational motion was reinforced by functional magnetic resonance imaging studies. Translational motion elicited no response in the MT complex, although it did produce a strong response in many visual areas when contrasted with blank stimuli. However, radial and rotational motion produced a normal pattern of activation in a subregion of the MT complex. These data reinforce the existent evidence for independent cortical processing for translational, and circular or radial flow motion, and further suggest that the two systems have different vulnerability and plasticity to prenatal damage. They also highlight the complexity of visual motion perception, and how the delicate balance of neural activity can lead to paradoxical effects such as consistent misperception of the direction of motion. We advance a possible explanation of a reduced spatial sampling of the motion stimuli and report a simple model that simulates well the experimental results.

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.

Cerebral palsy

Cerebral palsy (CP) is the leading cause of childhood disability. This article reviews common presentations of CP and its possible causes. The management of common problems seen in affected children is discussed in a system-based approach. Many treatment options are available for CP, with varying degrees of evidence and acceptance. As individuals who have CP transition into adulthood, they face unique issues that are not well recognized in the medical community. This article briefly reviews the psychosocial impact of this chronic disease on individuals and their caregivers and family.

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 execution of microsaccades related to reading skills, in cerebral palsied children

This article investigates the ability of cerebral palsied (CP) children to execute microsaccades. One-hundred and five congenitally CP school aged children (6 to 15 years old), without severe mental retardation, were classified into three groups: those with spastic quadriplegi, spastic diplegics, and spastic hemiplegics on the basis of: (1) patient anamnesis, (2) IQ estimation, (3) evaluation of the microsaccadic skills with the Developmental Eye Movement test (DEM). Their performance in these tests was compared with a control group from the general pediatric population. IQ of the CP children ranged between 70 and 100; the microsaccadic skills were severely affected: only 19% of the CP children had normal function, 20.9% of the CP children appeared with a pure oculomotor problem, 32.4% of the CP children had a visual-perceptual problem, and 27.7% of the CP children had a combined oculomotor and visual perceptual problem. CP children, in the absence of severe mental retardation, have disturbed visual skills and visual perception that usually leads to reading difficulties. It is also suggested that microsaccadic skills of CP children is an identifiable factor compounding the adverse effects of mental retardation on reading skills.

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.

Global perception of small numerosities (subitizing) in cerebral-palsied children

The goal of this study was to investigate how global perception of small numerosities (subitizing) develops in cerebral-palsied children (CP), as compared to control children. Twenty-nine 4- to 8-year-old CP children were compared to controls matched on age and sex. Both groups were asked to quantify sets of one to six items displayed briefly on a screen (250 ms). The children were also assessed on counting and eye-hand coordination. CP children exhibited a lower subitizing limit than control children. In CP and control children, the subitizing limit increased significantly with age. In CP children, the subitizing limit was positively correlated with counting performance, and both were positively correlated with eye-hand coordination. In addition, the subitizing limit in CP children with no evidence of a right-hemisphere lesion tended to be higher than in children with a right or bilateral lesion, suggesting right-hemisphere involvement in subitizing. These results support the idea that subitizing and counting are not independent processes during development, and argue in favor of a model of subitizing that relies on a global process.

Manual skill, hand skill asymmetry, and neuropsychological test performance in schoolchildren with spastic cerebral palsy

Bilateral hand skill assessment with a computerised version of the Peg Moving Task, and neuropsychological testing, were performed in 30 children aged 7 to 8 years with spastic cerebral palsy (CP) and without mental retardation, diplegia (n = 10), right hemiplegia (n = 10), or left hemiplegia (n = 10), and in 30 controls. Compared to controls: (i) 30% of the hemiplegic children showed impairment of the unaffected hand and 70% of the diplegic children showed impairment in both hands; (ii) children with CP were impaired only in oral repetition and in visual-motor tasks. Results of neuropsychological testing were not significantly different between the three groups of children with CP. Right minus left asymmetry in hand skill was not related to neuropsychological testing; however, degree of impairment of the right hand was associated with phonological and metaphonological skills, and of the left hand with visuospatial and counting performance. Hand skill was related to the ability to perform many daily living manual activities. It is concluded that impairment of hand function, rather than the side of the more affected hand, is related to neuropsychological deficits in children with cerebral palsy.

What impairs subitizing in cerebral palsied children?

The goal of this study was to investigate the factors responsible for the low subitizing limit of cerebral palsied (CP) children. For this purpose, 44 CPs were tested on two tasks involving the rapid recognition of dot configurations. The answer was either a number (subitizing task) or the name of a pattern (pattern recognition task). The CPs were compared to controls of the same age. All children were evaluated for visual and visuospatial short-term memory. The results showed that CPs with a low subitizing limit did not do better with a canonical arrangement than the random one, were impaired to the same extent on the pattern recognition task as on the subitizing task, and had a short visuospatial short-term memory span. These results suggest that the low subitizing limit of CPs stems from a (non-number-dependent) lesser capacity to perceive a dot configuration as a gestalt. A low subitizing limit was almost always associated with a right-hemisphere lesion.

Visual-perceptual impairment in children with periventricular leukomalacia

We set out to define visuo-perceptual impairment related to periventricular leukomalacia (PVL) using the Developmental Test of Visual Perception (DTVP). Correlations were sought between visual-perceptual deficits and DTVP profile and neuroradiological and neurophthalmological findings. The DTVP was administered to 20 children (m/f: 10/10), aged between 5 and 8 years (mean: 6.95 years), presenting with: spastic diplegia; PVL documented by brain MRI; normal or mildly impaired visual acuity; mild-moderate upper limb functional impairment. The mean General Visual-Perceptual Quotient was impaired, showing a great variability among the patients. Despite this, an uneven DTPV profile, characterised by a significant difference between the VMIQ and the Non-Motor Visual-Perceptual Quotient (P < 0.001) and a poor result on the Closure subtest (identification of whole figures from incomplete visual information) was observed in all the subjects. This profile reflects a deficit in eye-hand coordination and in praxic-constructional abilities and could be the expression of malfunctioning of the occipital-parietal pathway of visual integration, the so-called 'dorsal stream,' a hypothesis reinforced by the emergence of a statistically significant correlation between the neuroradiological data and the presence of visual-perceptual impairment.

The dissociation of perception and cognition in children with early brain damage

Reduced non-verbal compared to verbal intelligence is used in many outcome studies of perinatal complications as an indication of visual perceptual impairment. To investigate whether this is justified, we re-examined data sets from two previous studies, both of which used the visual perceptual battery L94. The first study comprised 47 children at risk for cerebral visual impairment due to prematurity or birth asphyxia, who had been administered the McCarthy Scales of Children's abilities. The second study evaluated visual perceptual abilities in 82 children with a physical disability. These children's intellectual ability had been assessed with the Wechsler Intelligence Scale for Children-Revised and/or Wechsler Pre-school and Primary Scale of Intelligence-Revised. No significant association was found between visual perceptual impairment and (1) reduced non-verbal to verbal intelligence; (2) increased non-verbal subtest scatter; or (3) non-verbal subtest profile deviation, for any of the intelligence scales. This result suggests that non-verbal intelligence subtests assess a complex of cognitive skills that are distinct from visual perceptual abilities, and that this assessment is not hampered by deficits in perceptual abilities as manifested in these children.

Developmental sequence of postural control in prone position in children with spastic diplegia

The aim of this study was to assess the development of postural control in the prone position in children with spastic diplegia and triplegia, and determine the influence of clinical characteristics, visual acuity and cognitive performance on that development. We also analysed the relation between these early motor achievements in the prone position and the subsequent acquisition of motor competence in the sitting position. We followed 24 diplegic and triplegic children from before age 2 years (mean age 12 months) to mean age 41 months, videorecording motor behaviour every six months and abstracting acquisitions in alignment and balance using a standardised procedure. We confirm a developmental sequence of all the acquired movements in the prone position. 83.3% of the children completed the uprighting sequence in the sagittal plane, acquired good balance, and ability to rotate the head and trunk. 70.8% of the children (all but one of the diplegic children and none among triplegic children) acquired symmetric posture in the frontal plane and 83.3% reduced leg hyperextension. Development was not uniform, and at 12-18 months two groups began to emerge: diplegic children who rapidly achieved all or most of the steps in the sequence and had a favourable prognosis for subsequent motor development; and triplegic children who achieved these steps at a much slower rate or in some cases not at all and had a less favourable prognosis for future development. Diplegic children with normal visual acuity, and general quotient GQ>70 did better than triplegic children with compromised visual acuity and GQ<70. Acquisition of the full uprighting sequence in the prone position before the age of two related to the later acquisition of autonomous sitting.