Identifying and characterising cerebral visual impairment in children: a review

Eyes on CVI: Eye movements unveil distinct visual search patterns in Cerebral Visual Impairment compared to ADHD, dyslexia, and neurotypical children

Visual search problems are often reported in children with Cerebral Visual Impairment (CVI). To tackle the clinical challenge of objectively differentiating CVI from other neurodevelopmental disorders, we developed a novel test battery. Visual search tasks were coupled with verbal and gaze-based measurements. Two search tasks were performed by children with CVI (n: 22; mean age (SD): 9.63 (.46) years) ADHD (n: 32; mean age (SD): 10.51 (.25) years), dyslexia (n: 28; mean age (SD): 10.29 (.20) years) and neurotypical development (n: 44; mean age (SD): 9.30 (.30) years). Children with CVI had more impaired search performance compared to all other groups, especially in crowded and unstructured displays and even when they had normal visual acuity. In-depth gaze-based analyses revealed that this group searched in overall larger areas and needed more time to recognize a target, particularly after their initial fixation on the target. Our gaze-based approach to visual search offers new insights into the distinct search patterns and behaviours of children with CVI. Their tendency to overlook targets whilst fixating on it, point towards higher-order visual function (HOVF) deficits. The novel method is feasible, valid, and promising for clinical differential-diagnostic evaluation between CVI, ADHD and dyslexia, and for informing individualized training.

Long-term visual and neurodevelopmental outcomes in children with Congenital Zika Syndrome after undergoing strabismus surgery

Purpose: To assess long-term visual and neurodevelopmental outcomes in children with congenital Zika syndrome (CZS) after strabismus surgery. Methods: A consecutive sample of five children with CZS who underwent strabismus surgery was enrolled. All children underwent a standardized pre- and postoperative protocol including binocular best-corrected visual acuity (BCVA) using the Teller Acuity Cards II (TAC II), ocular alignment, functional vision using the functional vision developmental milestones test (FVDMT), and neurodevelopmental milestone evaluation using the Bayley Scales of Infant Development-Third Edition (BSID-III). Scores of the FVDMT outcomes considering the child's developmental age based on the BSID-III score were compared with scores from postoperative assessment. Results: Five children with CZS (3 girls, 2 boys) were enrolled with a mean age at baseline (preoperative) of 35.0 ± 0.7 months (range, 34-36 months) and at final assessment of 64.4 ± 0.5 months (range, 64-65 months). Preoperative BCVA was 1.2 ± 0.5 logMAR and at final assessment 0.7 ± 0.1 logMAR. Successful strabismus surgery outcome was maintained in 4/5 (80.0%) of children at final assessment. The children's BSID-III scores showed significant neurodevelopment delay at the initial assessment (corresponding developmental mean age was 4.7 months) and at their final assessment (corresponding developmental mean age was 5.1 months). There was improvement or stability in 34/46 items evaluated in the FVDMT (73.9%) when comparing baseline with 2-year follow-up. Conclusions: Strabismus surgery resulted in long-term ocular alignment in the majority of children with CZS. All the children showed improvement or stability in more than 70.0% of the functional vision items assessed. Visual and neurodevelopmental dysfunction may be related to complex condition and associated disorders seen in CZS including ocular, neurological, and skeletal abnormalities.

Managing the apparently blind child presenting in the first year of life: A review

Severe vision impairment and blindness in childhood have a significant health burden on the child, family and society. This review article seeks to provide a structured framework for managing the apparently blind child presenting in the first year of life, starting from a comprehensive history and examination. Different investigation modalities and the increasingly important role of genetics will also be described, in addition to common causes of severe vision impairment. Crucially, a systematic approach to the blind infant is key to correct diagnoses and timely management. Incorrect diagnoses can be costly to all involved, however it is important to note that diagnoses can change with ongoing follow-up and investigations. Furthermore, the modern age of ophthalmology requires a multi-disciplinary approach and close collaboration with specialists including paediatricians, neurologists and geneticists, in addition to rehabilitation and low vision services, to ensure the best care for these vulnerable infants.

Parent-reported problems in children with Cerebral Visual Impairment: Improving the discriminative ability from ADHD and dyslexia using screening inventories

Daily problems of children with Cerebral Visual Impairment (CVI) are often misinterpreted as symptoms of behavioural disorders or learning disabilities instead of higher order visual function (HOVF) deficits. It is difficult to differentiate between various paediatric clinical groups based on daily manifestations. We used two CVI inventories (V-CVI-I, HVFQI) and an ADHD questionnaire (AVL) to compare parent-reported visual and behavioural problems of children with CVI, ADHD, dyslexia and neurotypical children (Age 6-15, Verbal Intelligence > 70). Our results show a higher percentage of parent-reported visual problems in children with CVI compared to all other groups, which was not affected by their visual acuity levels. On most HOVF categories, a higher percentage of parent-reported visual problems was also found in children with ADHD or dyslexia compared to neurotypical children. Children with ADHD had significantly more parent-reported behavioural problems, but more behavioural problems were reported by the parents of children with CVI compared to neurotypical children as well. Our findings complicate using the existing inventories for initial screening and referral of children with potential CVI. We propose a shortened screening list to improve the potential differentiation between CVI and ADHD or dyslexia based on parent-reported visual problems in everyday life.

Visual search patterns during exploration of naturalistic scenes are driven by saliency cues in individuals with cerebral visual impairment

We investigated the relative influence of image salience and image semantics during the visual search of naturalistic scenes, comparing performance in individuals with cerebral visual impairment (CVI) and controls with neurotypical development. Participants searched for a prompted target presented as either an image or text cue. Success rate and reaction time were collected, and gaze behavior was recorded with an eye tracker. A receiver operating characteristic (ROC) analysis compared the distribution of individual gaze landings based on predictions of image salience (using Graph-Based Visual Saliency) and image semantics (using Global Vectors for Word Representations combined with Linguistic Analysis of Semantic Salience) models. CVI participants were less likely and were slower in finding the target. Their visual search behavior was also associated with a larger visual search area and greater number of fixations. ROC scores were also lower in CVI compared to controls for both model predictions. Furthermore, search strategies in the CVI group were not affected by cue type, although search times and accuracy showed a significant correlation with verbal IQ scores for text-cued searches. These results suggest that visual search patterns in CVI are driven mainly by image salience and provide further characterization of higher-order processing deficits observed in this population.

Reliability and validity of the Japanese version of the Visual Function Classification System for children with cerebral palsy

BACKGROUND

Children with cerebral palsy (CP) often experience visual dysfunction that affects motor function and activities of daily living, but no 'gold standard' classification of visual function has been established. In recent years, however, a valid and reliable Visual Function Classification System (VFCS) for children with CP has been developed.

AIMS

To examine the reliability and validity of the Japanese version of the VFCS in individuals with CP.

METHODS

The translation of the VFCS was performed according to international standards for the translation of measurements. We conducted questionnaires of professionals (three physicians, eight physical therapists, five occupational therapists, six speech-language-hearing therapists and a certified orthoptist) regarding the content validity of the Japanese version of the VFCS. For reliability and concurrent validity, 148 individuals with CP were classified twice by professionals using the Japanese version of the VFCS, Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS), Communication Function Classification System (CFCS) and Eating and Drinking Ability Classification System (EDACS), with several weeks between each evaluation.

RESULTS

The content validity of the Japanese version of the VFCS almost met the criteria set. The percentage of positive and neutral opinions given by the professionals with regard to the four items ranged from 74% to 92%. The intra-rater reliability was 0.86 (95% CI 0.75-0.96) by Cohen's kappa and 0.93 (95% CI 0.88-0.96) by intraclass correlation coefficient. The inter-rater reliability was 0.67 (95% CI 0.56-0.78) by Cohen's kappa and 0.79 (95% CI 0.69-0.86) by intraclass correlation coefficient. The Spearman correlation coefficients between the VFCS and the GMFCS, MACS, CFCS and EDACS were 0.783, 0.764, 0.738, 0.738 and 0.830, respectively. The concurrent validity was confirmed by the correlations observed with other classification systems.

CONCLUSIONS

The results indicated good reliability and validity for the Japanese version of the VFCS.

Australian children with cerebral visual impairment: using what we know now to improve future approaches

PURPOSE

Little has been reported on Australian children with Cerebral Vision Impairment (CVI). This paper aims to present the outcome of an audit focussed on children with the primary diagnosis of CVI, using findings from the Australian Childhood Vision Impairment Register (ACVIR).

METHODS

Records on 132 children (49% girls, 51% boys) from ACVIR data gathered from both the child's parent/guardian and their eye health professional were reviewed. The child's demographics, level of vision impairment, birth history, diagnostic journey, secondary ocular diagnoses, comorbidities and low vision support were analyzed. Several correlations were investigated using a Kendall's tau-b analysis including the relationship between vision and age of diagnosis; level of vision and developmental delay; and age of suspicion of visual impairment and age of diagnosis.

RESULTS

The most common level of visual impairment was blindness (39%), and most children were suspected and diagnosed of visual impairment in the first 6 months of life. The majority of children were born full term (72%), weighing >2000gms (84%). Nearly half of the cohort of children (48%) had a secondary ocular diagnosis with 44% having nystagmus. The majority of children (80%) had additional health problems, and 85% of children had additional disabilities, with 79% having developmental delay.

CONCLUSION

While the findings of this audit cannot be generalized to a wider population of Australian children with CVI, the outcome encourages continued discussion on CVI, to explore comprehensive assessment approaches which facilitate timely and accurate diagnosis.

Validation of the Austin Assessment: A screening tool for cerebral visual impairment related visual issues

Cerebral visual impairment is the most common cause of vision impairment affecting children in the economically developed world with a prevalence rate of approximately 3.4%. Currently there are limited options for screening for cerebral visual impairment, resulting in many children going undiagnosed, especially those that have normal visual acuity. The aim of this research was to validate an iPad App called the Austin Assessment, which was developed as a potential screening tool for cerebral visual impairment related visual issues. The research involved three separate phases: (1) creating a database of normative ranges for children aged 5-18 across the different variables of the Austin Assessment, (2) using the Austin Assessment to screen children aged 5-13 to assess the effectiveness of the Austin Assessment as a screening tool for CVI related visual issues, and (3) conducting specific validation research assessing children using the Austin Assessment and an already validated visual search tool. Each phase used different quantitative research methodologies to help show the effectiveness of the Austin Assessment as a screening tool for cerebral visual impairment related visual issues. From phase one of the research, thresholds were established for three variables of the Austin Assessment for the age groupings of 5-8, 9-12 and 13-18. If a child meets one of these thresholds this indicates further assessment is required to determine if they do in fact have cerebral visual impairment related visual issues. Phase two identified 17 children out of 270 who had clinical findings indicating visual issues; potentially indicative of CVI; investigation into the nature of these visual issues is ongoing. Phase three found that the Austin Assessment has moderate diagnostic value for each age group, with good sensitivity and specificity, making it effective at distinguishing those children who have visual issues from those who have typical vision. Further investigation is needed to confirm this initial validation.

Childhood cerebral visual impairment subtype classification based on an extensive versus a limited test battery

Purpose

To classify CVI subtypes and compare the added value of an extensive test battery over a limited test battery in subtype classification of cerebral visual impairment (CVI) in children.

Methods

Seventy-five children with a clinical diagnosis of CVI (median [IQR] age: 9 [7-12] years) were identified from the medical records. The extensive test battery included visual acuity, contrast sensitivity, ocular alignment, eye movement analysis, visual field analysis, optic nerve head evaluation, and evaluation of visual perception. The limited test battery included visual acuity, contrast sensitivity, ocular alignment, and evaluation of visual perception. Principal component analysis (PCA) followed by cluster analysis was done, for both test batteries separately, to determine the optimum subtype classification for CVI.

Results

Fifty-one participants with an extensive test battery with mild to moderate visual impairment were included in the main analysis. This resulted in four CVI subtypes for the extensive test battery (subtle characteristics, higher-level visual function deficits, lower-level visual function deficits, and higher- and lower- level visual function deficits) and three CVI subtypes for the limited test battery (subtle characteristics, higher-level visual function deficits, and higher- and lower- level visual function deficits). There were significant differences between the subtypes for 9 out of 10 measures of the extensive and all 4 measures of the limited test battery (p < 0.05). The subtle characteristics subtype (extensive n = 19, limited n = 15) showed near normal lower and higher-level visual functions in both test batteries. The higher-level visual function deficits subtype (extensive n = 18, limited n = 24) showed near normal visual acuity combined with significant visual perceptual deficits in both test batteries; accompanied by visual pathways defects and abnormal eye movement behavior in the extensive test battery. The higher- and lower- level visual function deficits subtype (extensive n = 4, limited n = 12) showed both higher and lower-level visual function deficits in both test batteries, but application of the extensive test battery revealed additional visual pathways defects and abnormal eye movement behavior. The lower-level visual function deficits CVI subtype (extensive n = 10) was a new subtype identified by the extensive test battery. This subtype showed lower-level visual function deficits together with abnormal eye movement measures.

Conclusion

This data-driven study has provided meaningful CVI subtype classifications based on the outcomes of various key functional and structural measures in CVI diagnosis. Comparison of the extensive test battery to the limited test battery revealed the added value of an extensive test battery in classifying CVI. The outcomes of this study, therefore, have provided a new direction in the area of CVI classification.

Motion and form coherence processing in individuals with cerebral visual impairment

AIM

Using a visual psychophysical paradigm, we sought to assess motion and form coherence thresholds as indices of dorsal and ventral visual stream processing respectively, in individuals with cerebral visual impairment (CVI). We also explored potential associations between psychophysical assessments and brain lesion severity in CVI.

METHOD

Twenty individuals previously diagnosed with CVI (mean age = 17 years 11 months [SD 5 years 10 months]; mean Verbal IQ = 86.42 [SD 35.85]) and 30 individuals with neurotypical development (mean age = 20 years 1 month [SD 3 years 8 months]; mean Verbal IQ = 110.05 [SD 19.34]) participated in the study. In this two-group comparison, cross-sectional study design, global motion, and form pattern coherence thresholds were assessed using a computerized, generalizable, self-administrable, and response-adaptive psychophysical paradigm called FInD (Foraging Interactive D-prime).

RESULTS

Consistent with dorsal stream dysfunction, mean global motion (but not form) coherence thresholds were significantly higher in individuals with CVI compared to controls. No statistically significant association was found between coherence thresholds and lesion severity.

INTERPRETATION

These results suggest that the objective assessment of motion and form coherence threshold sensitivities using this psychophysical paradigm may be useful in helping to characterize perceptual deficits and the complex clinical profile of CVI.

WHAT THIS PAPER ADDS

In participants with cerebral visual impairment (CVI), motion (but not form) coherence thresholds were significantly higher compared to controls. These psychophysical results support the notion of dorsal stream dysfunction in CVI.

Cerebral visual impairment and effect of phase-wise stimulation strategies-An interim analysis

Context

Cerebral visual impairment (CVI) is an overarching term, defined as a brain-based visual impairment with onset in childhood, unexplained by an ocular disorder and associated with unique visual and behavioral characteristics. Good vision and awareness of visual function in a child are highly essential as neuroplasticity is maximum in the first three years of life and response to intervention is utmost in this period. Awareness is lacking regarding CVI, and the diagnosis is largely missed. This can be easily addressed if a structured approach is employed.

Purpose

This study aims to evaluate the etiology and radiological correlation with the severity of CVI and outcome after structured intervention in children with CVI.

Settings and Design

Prospective-interventional study.

Methods and Material

Children attending the Child Development Centre (CDC) of a tertiary care hospital in North Karnataka and diagnosed with CVI in the age group of six months to 12 years and meeting the sampling criteria were screened and enrolled consecutively after obtaining parental consent/assent. Statistical analysis used is nonparametric test with SPSS software.

Results

Age showed a significant association with the phase of CVI. Perinatal insult was associated significantly with the severity of CVI. Magnetic resonance imaging (MRI) findings did not hamper the recovery of CVI.

Conclusions

Enrolment in early intervention programs tailored according to child's specific needs should be encouraged, with stress on ophthalmic screening of preterm and high-risk babies with perinatal hypoxia and history of convulsions, as early as six months.

Object identification in cerebral visual impairment characterized by gaze behavior and image saliency analysis

Individuals with cerebral visual impairment (CVI) have difficulties identifying common objects, especially when presented as cartoons or abstract images. In this study, participants were shown a series of images of ten common objects, each from five possible categories ranging from abstract black & white line drawings to color photographs. Fifty individuals with CVI and 50 neurotypical controls verbally identified each object and success rates and reaction times were collected. Visual gaze behavior was recorded using an eye tracker to quantify the extent of visual search area explored and number of fixations. A receiver operating characteristic (ROC) analysis was also carried out to compare the degree of alignment between the distribution of individual eye gaze patterns and image saliency features computed by the graph-based visual saliency (GBVS) model. Compared to controls, CVI participants showed significantly lower success rates and longer reaction times when identifying objects. In the CVI group, success rate improved moving from abstract black & white images to color photographs, suggesting that object form (as defined by outlines and contours) and color are important cues for correct identification. Eye tracking data revealed that the CVI group showed significantly greater visual search areas and number of fixations per image, and the distribution of eye gaze patterns in the CVI group was less aligned with the high saliency features of the image compared to controls. These results have important implications in helping to understand the complex profile of visual perceptual difficulties associated with CVI.

Altered neural oscillations underlying visuospatial processing in cerebral visual impairment

Visuospatial processing deficits are commonly observed in individuals with cerebral visual impairment, even in cases where visual acuity and visual field functions are intact. Cerebral visual impairment is a brain-based visual disorder associated with the maldevelopment of central visual pathways and structures. However, the neurophysiological basis underlying higher-order perceptual impairments in this condition has not been clearly identified, which in turn poses limits on developing rehabilitative interventions. Using combined eye tracking and EEG recordings, we assessed the profile and performance of visual search on a naturalistic virtual reality-based task. Participants with cerebral visual impairment and controls with neurotypical development were instructed to search, locate and fixate on a specific target placed among surrounding distractors at two levels of task difficulty. We analysed evoked (phase-locked) and induced (non-phase-locked) components of broadband (4-55 Hz) neural oscillations to uncover the neurophysiological basis of visuospatial processing. We found that visual search performance in cerebral visual impairment was impaired compared to controls (as indexed by outcomes of success rate, reaction time and gaze error). Analysis of neural oscillations revealed markedly reduced early-onset evoked theta [4-6 Hz] activity (within 0.5 s) regardless of task difficulty. Moreover, while induced alpha activity increased with task difficulty in controls, this modulation was absent in the cerebral visual impairment group identifying a potential neural correlate related to deficits with visual search and distractor suppression. Finally, cerebral visual impairment participants also showed a sustained induced gamma response [30-45 Hz]. We conclude that impaired visual search performance in cerebral visual impairment is associated with substantial alterations across a wide range of neural oscillation frequencies. This includes both evoked and induced components suggesting the involvement of feedforward and feedback processing as well as local and distributed levels of neural processing.

Cognition and learning difficulties in a representative sample of school-aged children with cerebral palsy

BACKGROUND

Nearly half of all children with CP experience intellectual impairment, with impacts on academic achievement.

AIMS

To assess cognitive and academic functioning for primary-school aged children with CP METHODS AND PROCEDURES: This population-based cohort study assessed 93 participants (male n = 62; mean = 9 years 9 months, SD 1 y 1.8 months) on measures of fluid and crystallised intelligence (Raven's Coloured Progressive Matrices, Peabody Picture Vocabulary Test) and academic achievement (Wechsler Individual Achievement Test). Analyses included t-tests, Pearson's chi-square and regression.

OUTCOMES AND RESULTS

41 (44.1%) children met criteria consistent with intellectual developmental disorder. Academic skills were significantly below population means on word reading (M= 85.4, SD = 19.3), t(66) = -6.2, p < .001; spelling (M=83.3, SD=19.7) t(65) = -6.87, p < .001; and numerical operations (M=72.9, SD=21.7) Z = 66.0, p < .001. Cognitive ability was associated with GMFCS level (χ² (1, N = 93) = 16.15, p < .001) and diagnosis of epilepsy (χ² (2, N = 93) = 11.51 p = .003). Crystallised and fluid intelligence together accounted for 65% of the variance in word reading, 56% in spelling and 52% in numerical operations.

IMPLICATIONS

Many children with CP experience academic challenges. Screening is recommended for all children with CP and full psychoeducational assessment undertaken when children with CP experience academic difficulties.

A Scoping Review of Intervention for Pediatric Cerebral Visual Impairment: Calling All Pediatric Occupational Therapists

Cerebral visual impairment is the leading cause of low vision in children, and functional gains can be achieved with intervention. To date there exists no evidence-based intervention protocol to guide rehabilitation therapists. This scoping review was conducted to synthesize the evidence currently available and explore current interventions in order to guide future research. This review identified five types of interventions for cerebral visual impairment; habilitation, visual stimulation, video game, color tent, and medical and also evidenced the need for standardized, objective measures of function for this population.

Development of an integrated telerehabilitation model in children with cerebral visual impairment in South India during the COVID-19 pandemic - A pilot study

Purpose

Coronavirus disease 2019 (COVID-19) pandemic affected the in-person rehabilitation/habilitation services in families with children with cerebral visual impairment (CVI) in India. This study aimed to develop a structured and family-centered telerehabilitation model alongside conventional in-person intervention in children with CVI to observe its feasibility in the Indian population.

Methods

This pilot study included 22 participants with a median age of 2.5 years (range: 1-6) who underwent a detailed comprehensive eye examination followed by functional vision assessment. The visual function classification system (VFCS) was administered to the children and the structured clinical question inventory (SCQI) to the parents. Every participant underwent 3 months of telerehabilitation including planning, training, and monitoring by experts. At 1 month, the parental care and ability (PCA) rubric was administered to the parents. After 3 months, in an in-person follow-up, all the measures were reassessed for 15 children.

Results

After 3 months of Tele-rehabilitation there were significant improvements noted in PCA rubric scores (P<0.05). Also, statistically significant improvements were noted in functional vision measured using SCQI and VFCS scores (P<0.05) compared to baseline.

Conclusion

The outcomes of the study provide the first steps towards understanding the use of a novel tele-rehabilitation model in childhood CVI along-side conventional face-to-face intervention. The added role of parental involvement in such a model is highly essential.

[Formula: see text] Visual selective attention and visual search performance in children with CVI, ADHD, and Dyslexia: a scoping review

Visual selective attention refers to the selection of relevant visual elements in a scene whilst ignoring irrelevant visual elements. Visual Selective Attention Dysfunctions (VSAD) are prevalent in children with Cerebral Visual Impairment (CVI), Attention Deficit Hyperactivity Disorder (ADHD), and Dyslexia. An important issue in the pediatric neuropsychological practice is how to discriminate between the task performance of these populations. We conducted a scoping review of the literature on visual search performance (VSP) in children with CVI, ADHD, and Dyslexia, aged 6-12 years. After a systematic selection process, 35 studies were included. Results suggest that all patient groups have some degree of impaired VSP compared to typically developing children. Children with CVI tend to react slower and less accurately. VSP impairments in children with ADHD are characterized by poor accuracy rather than reaction time. Children with Dyslexia tend to be slower and less accurate, depending on stimulus type. Besides VSAD, it is argued that other neurocognitive mechanisms might influence VSP, such as speed-accuracy trade-off or an executive functioning deficit in ADHD and a phonological deficit in Dyslexia. This paper further discusses the differences and similarities in visual search performance between the groups. The sparse data in children with an official diagnosis of CVI and the technical inconclusive data on children with ADHD and Dyslexia demonstrate complexity of discriminating between these populations in clinical practice based on VSP. New and more quantitative VSP parameters, such as eye tracking-based measures, may contribute to a refined classification among CVI, ADHD, and Dyslexia.

"Even though a lot of kids have it, not a lot of people have knowledge of it": A qualitative study exploring the perspectives of parents of children with cerebral/cortical visual impairment

BACKGROUND

Cerebral/Cortical Visual Impairment (CVI) is the leading cause of visual impairment in children and can negatively impact participation in daily activities.

METHODS AND PROCEDURE

This qualitative study used virtual focus groups and an online questionnaire to understand the perspectives of families with children who have CVI. Constant comparison analysis was used to analyze focus group transcripts and extract themes. The PEDI-CAT and an online questionnaire were administered to characterize the study population.

OUTCOMES AND RESULTS

Four themes were identified: (1) Awareness of CVI and its effect on the child and family, (2) Parent experiences, (3) Child factors and functional implications, and (4) Supports that enhance child development/vision.

CONCLUSIONS AND IMPLICATIONS

Findings from this study highlight the substantial impact that lack of CVI awareness had on parent experiences. Lack of awareness led to late diagnosis, missed intervention opportunities, and caregiver burden. Due to insufficient resources, parents had to educate themselves and service providers about CVI and advocate for their child's needs. Healthcare and educational providers who work with pediatric neurodevelopmental populations must be knowledgeable about clinical features of CVI, task and environmental adaptations to support vision and implementation of family-centered care.

From vision to cognition: potential contributions of cerebral visual impairment to neurodevelopmental disorders

Vision has a crucial role to play in human development and functioning. It is, therefore, not surprising that vision plays a fundamental role in the development of the child. As a consequence, an alteration in visual function is, therefore, likely to hinder the child's development. Although ocular disorders are well known, diagnosed and taken into account, cerebral visual impairments (CVI) resulting from post-chiasmatic damage are largely underdiagnosed. However, among the disorders resulting from an episode of perinatal asphyxia and/or associated with prematurity, or neonatal hypoglycaemia, CVIs are prominent. In this article, we focus on the role of the possible effects of CVI on a child's learning abilities, leading to major difficulty in disentangling the consequences of CVI from other neurodevelopmental disorders (NDD) such as dyslexia, dyscalculia, dysgraphia, attention-deficit/hyperactivity disorder (ADHD), developmental coordination disorder (DCD) and autism spectrum disorders (ASD). Although we focus here on the possible overlap between children with CVI and children with other NDD, De Witt et al. (Wit et al. Ear Hear 39:1-19, 2018) have raised exactly the same question regarding children with auditory processing disorders (the equivalent of CVI in the auditory modality). We underline how motor, social and cognitive development as well as academic success can be impaired by CVI and raise the question of the need for systematic evaluation for disorders of vision, visual perception and cognition in all children presenting with a NDD and/or previously born under adverse neurological conditions.

Social attention and social-emotional modulation of attention in Angelman syndrome: an eye-tracking study

Individuals with Angelman syndrome (AS) present with severe intellectual disability alongside a social phenotype characterised by social communication difficulties and an increased drive for social engagement. As the social phenotype in this condition is poorly understood, we examined patterns of social attention and social modulation of attention in AS. Twenty-four individuals with AS and twenty-one young children with similar mental age were shown videos featuring unfamiliar actors who performed simple actions across two conditions: a playful condition, in which the actor showed positive facial emotions, and a neutral condition, in which the actor showed a neutral facial expression. During the passive observation of the videos, participants' proportion of time spent watching the two areas of interest (faces and actions) was examined using eye-tracking technology. We found that the playful condition elicited increased proportion of fixations duration to the actor's face compared to the neutral condition similarly across groups. Additionally, the proportion of fixations duration to the action area was similar across groups in the two conditions. However, children with AS looked towards the actor's face for a shorter duration compared to the comparison group across conditions. This pattern of similarities and differences provides novel insight on the complex social phenotype of children with AS.

Visual and cognitive profiles in children with and without cerebral visual impairment

Reliable differentiation of visual-perceptual difficulties in children with and without cerebral visual impairment (CVI) can often pose a diagnostic challenge. We, therefore, assessed the visual-perceptual profile in 94 children with and 77 children without suspected CVI between the ages of 8 and 17 years in a non-clinical setting, using a screening questionnaire and standardized visual-perceptual tests. Children with suspected CVI reported more frequently greater visual difficulties, had lower visual acuity, and were significantly impaired in visual search tests, in visual form and object perception, in visual space perception, and in visual text processing. There were no significant differences between groups in stereopsis, fixation stability, motility, horizontal saccadic eye movements, and convergence and accommodation. Cognitive performance in auditory attention and verbal short-term and working memory was similar in both groups. Our results indicate that the use of an appropriate questionnaire and specific visual-perceptual tests enables valid diagnostic detection of CVI. The additional use of cognitive tests also allows differentiation between primary and secondary impairments in visual perception.

Make it easier: 3-word strategies to help children with cerebral visual impairment use their vision more effectively

INTRODUCTION

Cerebral Visual Impairment (CVI) is the most common cause of visual impairment in children in the United Kingdom. Management relies on identifying strategies and adaptations which enable the child to use their vision effectively and efficiently. The majority of published strategies involve lengthy inventories used in a specialist setting. Feedback from parent support groups cite the provision of immediate advice on strategies at the time of diagnosis as a key indicator of good care. The aim of the study was to use the Delphi technique to construct a set of three-word phrases to succinctly describe strategies for common visual dysfunctions in children with CVI.

METHOD

A panel of twelve experts across health, education and those with lived experience was recruited. Four rounds of questionnaires were used to reach consensus on candidates symptoms and suggestions for 3-word-phrases. Consensus was defined as 70% agreement.

RESULTS

Response rates were 92, 67, 92 and 91% for each round respectively. The 3-word phrases reaching consensus were: Big Bold Bright; Keep it Still; Eyes or Ears; Show It High; Better on Left/Right; Clear the Clutter; Keep It Short; Give Me Time, My Vision Varies, Just One Thing.

CONCLUSION

The intention is for the phrases presented to act as a 'starter' at the point of diagnosis and are appropriate for children of any developmental or visual ability. The real-life validation of this set of expert-consensus phrases will require further studies, evaluating both their effectiveness in terms of mapping to an intervention and impact on visual development.

Neurovisual profile in children affected by Angelman syndrome

BACKGROUND

Angelman syndrome (AS) is a rare neurogenetic disorder caused by altered expression of the maternal copy of the UBE3A gene. Together with motor, cognitive, and speech impairment, ophthalmological findings including strabismus, and ocular fundus hypopigmentation characterize the clinical phenotype. The aim of this study was to detail the neurovisual profile of children affected by AS and to explore any possible genotype-phenotype correlations.

METHODS

Thirty-seven children (23 females, mean age 102.8 ± 54.4 months, age range 22 to 251 months) with molecular confirmed diagnosis of AS were enrolled in the study. All underwent a comprehensive video-recorded neurovisual evaluation including the assessment of ophthalmological aspects, oculomotor functions, and basic visual abilities.

RESULTS

All children had visual impairments mainly characterized by refractive errors, ocular fundus changes, strabismus, discontinuous/jerky smooth pursuit and altered saccadic movements, and/or reduced visual acuity. Comparing the neurovisual profiles between the deletion and non-deletion genetic subgroups, we found a significant statistical correlation between genotype and ocular fundus hypopigmentation (p = 0.03), discontinuous smooth pursuit (p < 0.05), and contrast sensitivity abnormalities (p < 0.01) being more frequent in the deletion subgroup.

CONCLUSIONS

Subjects affected by AS present a wide spectrum of neurovisual impairments that lead to a clinical profile consistent with cerebral visual impairment (CVI). Moreover, subjects with a chromosome deletion show a more severe visual phenotype with respect to ocular fundus changes, smooth pursuit movements, and contrast sensitivity. Early detection of these impaired visual functions may help promote the introduction of neurovisual habilitative programs which can improve children's visual, neuromotor, and cognitive outcomes.

Including visual orienting functions into cerebral visual impairment screening: Reliability, variability, and ecological validity

BACKGROUND

Cerebral visual impairment (CVI) is a heterogeneous brain-based visual processing disorder in which basic visual orienting functions (VOF) and higher-order perception can be impaired.

AIMS

To evaluate (1) the test-retest reliability and variability of an eye tracking-based VOF paradigm, and related clinical characteristics, and (2) the relations between VOF (variability) and daily visual functioning and visuoperceptual dimensions.

METHODS AND PROCEDURES

Thirty-three children with CVI (Males=14; mean age=9 years 10 months) underwent eye tracking thrice, completed a visuoperceptual battery, and parents completed the Flemish CVI questionnaire. VOF reliability and variability of reaction time (RTF), fixation duration and accuracy were assessed with intraclass correlation coefficient (ICC), Bland-Altman plots, and coefficient of variation. Relations were analysed with linear mixed models.

OUTCOMES AND RESULTS

Highly salient visual stimuli had good RTF reliability (ICCs=0.75) and triggered less variable VOF. Intermediate and low salience stimuli had poor-to-moderate reliability and triggered more variable VOF. Younger performance age related to more VOF variability. Greater visual (dis)interest, clutter and distance viewing impairments, and a weaker visuoperceptual profile related to slower RTF.

CONCLUSIONS AND IMPLICATIONS

Highly salient stimuli reveal a child's 'optimal' visual performance, whereas intermediate and low salience stimuli uncover VOF variability, which is a key CVI hallmark to detect.

Decreased visual acuity is related to thinner cortex in cognitively normal adults: cross-sectional, single-center cohort study

Background

Decreased visual acuity (VA) is reported to be a risk factor for dementia. However, the association between VA and cortical thickness has not been established. We investigated the association between VA and cortical thickness in cognitively normal adults.

Method

We conducted a cross-sectional, single-center cohort study with cognitively normal adults (aged ≥ 45) who received medical screening examinations at the Health Promotion Center at Samsung Medical Center. Subjects were categorized as bad (VA ≤ 20/40), fair (20/40 < VA ≤ 20/25), and good (VA > 20/25) VA group by using corrected VA in the Snellen system. Using 3D volumetric brain MRI, cortical thickness was calculated using the Euclidean distance between the linked vertices of the inner and outer surfaces. We analyzed the association between VA and cortical thickness after controlling for age, sex, hypertension, diabetes, dyslipidemia, intracranial volume, and education level.

Results

A total of 2756 subjects were analyzed in this study. Compared to the good VA group, the bad VA group showed overall thinner cortex (p = 0.015), especially in the parietal (p = 0.018) and occipital (p = 0.011) lobes. Topographical color maps of vertex-wise analysis also showed that the bad VA group showed a thinner cortex in the parieto-temporo-occipital area. These results were more robust in younger adults (aged 45 to 65) as decreased VA was associated with thinner cortex in more widespread regions in the parieto-temporo-occipital area.

Conclusion

Our results suggest that a thinner cortex in the visual processing area of the brain is related to decreased visual stimuli.

Assessing visuospatial processing in cerebral visual impairment using a novel and naturalistic static visual search task

BACKGROUND

Cerebral visual impairment (CVI) is a brain based visual disorder associated with the maldevelopment of central visual pathways. Individuals with CVI often report difficulties finding a target of interest in cluttered and crowded visual scenes. However, it remains unknown how manipulating task demands and other environmental factors influence visual search performance in this population.

AIM

We developed a novel and naturalistic virtual reality (VR) based static visual search task combined with eye tracking called the "virtual toy box" to objectively assess visual search performance in CVI.

METHODS AND PROCEDURES

A total of 38 individuals with CVI (mean age 13.18 years ± 3.58 SD) and 53 controls with neurotypical development (mean age 15.25 years ± 5.72 SD) participated in the study. In a first experiment, study subjects were instructed to search for a preselected toy presented among a varying number of surrounding distractor toys (set size ranging from 1 to 36 items). In a second experiment, we assessed the effects of manipulating item spacing and the size of the visual area explored (field of view; FOV).

OUTCOMES AND RESULTS

Behavioral outcomes collected were success rate, reaction time, gaze error, visual search area, and off-screen percent (an index of task compliance). Compared to age-matched controls, participants with CVI showed an overall impairment with respect to all the visual search outcomes of interest. Specifically, individuals with CVI were less likely and took longer to find the target, and search patterns were less accurate and precise compared to controls. Visual search response profiles were also comparatively less efficient and were associated with a slower initial pre-search (visual orienting) response as indexed by higher slope and intercept values derived from the analysis of reaction time × set size functions. Search performance was also more negatively affected in CVI at the smallest as well as largest spacing conditions tested, while increasing FOV was associated with greater decreased gaze accuracy and precision CONCLUSIONS AND IMPLICATIONS: These results are consistent with a general profile of impaired visual search abilities in CVI as well as worsening performance with increased visual task demands and an overall sensitivity to visual clutter and crowding. The observed profile of impaired visual search performance may be associated with dysfunctions related to how visual selective attention is deployed in individuals with CVI.

Providing a Primary Care Medical Home for Children and Youth With Cerebral Palsy

Cerebral palsy (CP) is the most common motor disorder of childhood, with prevalence estimates ranging from 1.5 to 4 in 1000 live births. This clinical report seeks to provide primary care physicians with guidance to detect children with CP; collaborate with specialists in treating the patient; manage associated medical, developmental, and behavioral problems; and provide general medical care to their patients with CP.

Development and validation of the Visual Function Battery for Children with Special Needs

AIM

To develop and validate the Visual Function Battery for Children with Special Needs (VFB-CSN).

METHOD

This was a scale development and validation study with (1) construct and item generation and (2) evaluations of interrater reliability, acceptability, and content, ecological, and convergent validities.

RESULTS

Children with special needs were recruited for the reliability (n = 32) and validity (n = 95) investigations. The construct and items were generated based on literature review and an expert panel. We constructed eight categories, namely visual reflex, ocular muscle balance, visual acuity, oculomotor, visual field, contrast sensitivity, colour/form vision, and visual attention. Both functional assessment and standardized tests were adopted. The reliabilities were high for the whole VFB-CSN (intraclass correlation coefficient [ICC] = 0.90, 95% confidence interval [CI] = 0.80-0.90) and good for the oculomotor, contrast sensitivity, and colour/form vision (ICC = 0.80-0.86, 95% CI = 0.50-0.93). Correlations between the VFB-CSN and the Functional Vision Questionnaire were strong and acceptable for the contrast sensitivity, acuity, and colour/form vision (r = 0.79, r = 0.69, r = 0.69, r = 0.70 respectively). The correlation between the VFB-CSN and standardized visual acuity test was acceptable (r = -0.72).

INTERPRETATION

The VFB-CSN is a reliable and valid multifaceted battery for children with special needs. Acceptable psychometric properties were also found for the acuity and contrast sensitivity.

Surgical outcomes and observation in exotropia cerebral palsy children with cortical visual impairment

PURPOSE

Cortical visual impairment (CVI) is the common cause of pediatric visual impairment in cerebral palsy (CP) while exotropia is the most common strabismus associated with CP. We aim to observe the strabismic surgery outcomes in pediatric patients with CP and CVI.

METHOD

Our medical records were collected from pediatric patients treated in our hospital from May 1, 2017 to Jan 1, 2022. With normal intelligence assessment and diagnosis of exotropia in children with CP and CVI, microsurgeries were performed under intravenous combined inhalation anesthesia. The strabismus was examined by the prism test under best vision correction and the contrast sensitivity testing (CST) was measured at five levels of spatial frequencies.

RESULT

A total of 38 exotropia patients with CP and CVI were identified and included for analysis during the study period with age ranged from 5 to 12 years (mean 8.45 years) and mean follow up duration was 8.7 months (6-42 months). After bilateral lateral rectus recession (with/without medial rectus resection or inferior oblique transposition), the exotropia amount of participants were obviously revealed from - 30 ~ - 140 (median, IQR: - 50, 40) prism diopters (PD) preoperatively to 0 ~ - 15 (0, 5) PD postoperatively. Statistically significantly improvements were observed at all levels of spatial frequency on CST postoperatively, especially at high spatial frequency areas (p < 0.05).

CONCLUSION

Our results demonstrated that the effect of strabismus surgery on exotropia in children with CP and CVI were stable and monocular contrast sensitivity post- operation increased significantly at all spatial frequencies levels.

The Developmental Eye Movement Test Does Not Detect Oculomotor Problems: Evidence from Children with Nystagmus

SIGNIFICANCE

The Developmental Eye Movement (DEM) test, a test purported to assess oculomotor skills, does not detect eye movement disorder in nystagmus syndromes. The test should not be used for the clinical evaluation of oculomotor disorders.

PURPOSE

The DEM test ratio compares a horizontal number naming subtest with a vertical one to identify oculomotor problems independent of a child's visual-verbal naming skills. Here, we tested the construct validity of this method by comparing scores of children with and without pathologic nystagmus. Such a nystagmus disturbs normal fixation and saccadic behavior because of the presence of involuntary rhythmic oscillations of the eyes. Therefore, if the ratio is indeed a comprehensive measure of oculomotor problems, children with nystagmus should show an increased ratio score.

METHODS

The DEM test performances of normally sighted children (n = 94), children with ocular visual impairments (VI o ; n = 33), and children with cerebral visual impairment (n = 30) were analyzed using linear regression. Part of the children with VI o and cerebral visual impairment had either fusion maldevelopment nystagmus syndrome (n = 8) or infantile nystagmus syndrome (n = 20), whereas the others showed no pathologic nystagmus.

RESULTS

The times needed for the horizontal and vertical subtests were significantly different between children with normal vision, VI o , and cerebral visual impairment ( P < .001). However, the presence of nystagmus did not add significantly to the horizontal and vertical times ( P > .20), nor did it have an effect on the ratio ( P > .10).

CONCLUSIONS

The DEM test ratio is not sensitive to fixation and saccade abnormalities associated with nystagmus, indicating that it does not have general construct validity to detect true eye movement disorders. Although not suitable for the evaluation of oculomotor disorders, the subtests do have clinical relevance in the diagnosis of cerebral visual impairment.

Longitudinal neurological analysis of moderate and severe pediatric cerebral visual impairment

Introduction

Cerebral visual impairment (CVI) results from damage to cerebral visual processing structures. It is the most common cause of pediatric visual impairment in developed countries and rising in prevalence in developing nations. There is currently limited understanding on how neurologic, developmental, and ophthalmic factors predict outcome for pediatric CVI.

Method

A retrospective manual chart review of pediatric CVI patients seen at the tertiary pediatric hospital neurology and neuro-ophthalmology service between 2010 and 2019 was conducted. Patients were stratified into severity groups (based on a custom CVI grading score), and followed over time to identify outcome predictors. Collected baseline characteristics included perinatal, genetic, developmental, and neurologic history, along with neuroimaging and fundoscopic findings on examination. Longitudinal data collected included age, seizure control, and type of therapy received. Linear mixed-effect models were used for longitudinal CVI grade outcome analysis.

Results

A total of 249 individuals spanning 779 patient visits were identified. Mean age at diagnosis was 18.8 ± 16.8 months (2–108 months). About 64.3% were born at term age. Perinatal history revealed hypoxic ischemic encephalopathy (HIE) in 16.5%, intraventricular hemorrhage (IVH) in 11.6%, and seizures in 21.7%. At presentation, 60.3% had a diagnosis of cerebral palsy and 84.7% had developmental delay. Among all subjects, 78.6% had epilepsy; 33.8% had an epileptic encephalopathy, with spasms/hypsarrhythmia being most common. Abnormal neuroimaging was present in 93.8%. Genetic anomalies were present in 26.9%. Baseline visual examination revealed no blink-to-light (BTL) in 24.5%; only BTL in 34.5%, fixation/tracking in 26.5%, and optokinetic drum follow in 14.4%. Longitudinal data analysis showed that perinatal history of HIE, a positive epilepsy history, using multiple (≥3) epilepsy medications, cerebral palsy, and abnormal fundoscopic findings were all negatively associated with CVI grade change over time. After controlling for significant confounders, receiving any type of therapy [early childhood intervention (ECI), physical and occupational therapy (PT/OT), refractive error correction or glasses] was significantly associated with longitudinal improvement in CVI grade compared to patients who did not receive any therapy, with glasses yielding the largest benefit.

Conclusion

This study offers extensive insights into neurologic, developmental and ophthalmologic features in patients with moderate to severe CVI. In concordance with previous findings, aspects of perinatal history and epilepsy/seizure control may help inform severity and prognosis in the general neurology or ophthalmology clinic. Conversely, these aspects, as well as genetic and specific epilepsy traits may alert vision health care providers in the clinic to pursue visual evaluation in at-risk individuals. Longitudinal follow-up of CVI patients showed that interventional therapies demonstrated vision function improvement greater than no therapy and maturational development.

The Effectiveness of Sensory Integration Interventions on Motor and Sensory Functions in Infants with Cortical Vision Impairment and Cerebral Palsy: A Single Blind Randomized Controlled Trial

Cortical vision impairment (CVI) and Cerebral Palsy (CP) lead to decrement in sensory and motor functions of infants. The current study examined the effectiveness of sensory integration interventions on sensory, motor, and oculomotor skills in infants with cortical vision impairment. Thirty-four infants with and CP aged 12−18 months were enrolled to the study. The infants were randomly divided into two groups as the control and intervention groups. The intervention group took sensory integration intervention 2 days a week for 8 weeks in addition to conventional physiotherapy 2 days a week for 8 weeks. The control group only received the conventional physiotherapy program 2 days a week for 8 weeks. The duration of the treatment sessions were 45 min for both interventions. Before and after the intervention, sensory processing functions were evaluated with the Test of Sensory Functions in Infants (TSFI), and motor functions were evaluated with the Alberta Infant Motor Scale (AIMS). There was a statistically significant difference between the pre- and post-test mean TSFI total and AIMS scores in the intervention group and control group (p < 0.001). The intervention group mean TSFI scores were more statistically significant than the those of the control group. Mean post-intervention AIMS scores did not differ between groups. Sensory integration intervention delivered with the conventional physiotherapy program was more effective than the conventional physiotherapy program in increasing sensory processing skills in one measure in infants with CVI and CP.

Assessing Higher-Order Visual Processing in Cerebral Visual Impairment Using Naturalistic Virtual-Reality-Based Visual Search Tasks

Cerebral visual impairment (CVI) is a brain-based disorder associated with the maldevelopment of central visual pathways. Individuals with CVI often report difficulties with daily visual search tasks such as finding a favorite toy or familiar person in cluttered and crowded scenes. We developed two novel virtual reality (VR)-based visual search tasks combined with eye tracking to objectively assess higher order processing abilities in CVI. The first (virtual toybox) simulates a static object search, while the second (virtual hallway) represents a dynamic human search task. Participants were instructed to search for a preselected target while task demand was manipulated with respect to the presence of surrounding distractors. We found that CVI participants (when compared to age-matched controls) showed an overall impairment with visual search on both tasks and with respect to all gaze metrics. Furthermore, CVI participants showed a trend of worsening performance with increasing task demand. Finally, search performance was also impaired in CVI participants with normal/near normal visual acuity, suggesting that reduced stimulus visibility alone does not account for these observations. This novel approach may have important clinical utility in helping to assess environmental factors related to functional visual processing difficulties observed in CVI.

Exploring the Need for Education on Cortical Visual Impairment Among Occupational Therapy Professionals and Teachers of Students With Visual Impairments

Introduction: Cortical or cerebral visual impairment (CVI) is the leading cause of bilateral visual impairment in developed countries. The goals of this study were to explore the CVI education and training received by occupational therapy practitioners and teachers of students with visual impairments and to quantify the confidence of these professionals to evaluate and work with children who are diagnosed with CVI. Methods: An Internet-based survey was conducted with a volunteer sample that included occupational therapists, certified occupational therapy assistants, and certified teachers of students with visual impairments who practice in 50 U.S. states; Washington, D.C.; and Canada. The survey was posted on professional organizations and social media websites, as well as emailed to colleagues at organizations such as the Association for the Education and Rehabilitation of the Blind and Visually Impaired, schools for students who are blind, and local universities. Data collection occurred between June 2019 and November 2019. Results: Surveys were completed by 205 respondents from 43 U.S. states; Washington, D.C.; and Canada. Occupational therapy practitioners consistently reported lower rates of formal education in CVI, with only 25% of occupational therapists and 47% of certified occupational therapy assistants receiving education on CVI in their academic programs. Less than 23% of occupational therapists received training on CVI assessments, whereas 75% of teachers of students with visual impairments had training in CVI assessments. Additionally, respondents indicated reduced satisfaction with their knowledge and skills for treating or teaching children with CVI. Discussion: The results indicate a gap in formal CVI education for occupational therapy practitioners and, to a lesser extent, teachers of students with visual impairments. Due to the increasingly high prevalence of CVI, the gap in formal education on CVI is significant. Implications for Practitioners: Results indicate the need to increase formal and continuing education for occupational therapy practitioners and teachers of students with visual impairments.

The Multidisciplinary Guidelines for Diagnosis and Referral in Cerebral Visual Impairment

Introduction

Cerebral visual impairment (CVI) is an important cause of visual impairment in western countries. Perinatal hypoxic-ischemic damage is the most frequent cause of CVI but CVI can also be the result of a genetic disorder. The majority of children with CVI have cerebral palsy and/or developmental delay. Early diagnosis is crucial; however, there is a need for consensus on evidence based diagnostic tools and referral criteria. The aim of this study is to develop guidelines for diagnosis and referral in CVI according to the grade method.

Patients and Methods

We developed the guidelines according to the GRADE method 5 searches on CVI (children, developmental age ≤ 18 years) were performed in the databases Medline, Embase, and Psychinfo, each with a distinct topic.

Results

Based on evidence articles were selected on five topics: 1. Medical history and CVI-questionnaires 23 (out of 1,007). 2. Ophthalmological and orthoptic assessment 37 (out of 816). 3. Neuropsychological assessment 5 (out of 716). 4. Neuroradiological evaluation and magnetic resonance imaging (MRI) 9 (out of 723). 5. Genetic assessment 5 (out of 458).

Conclusion

In medical history taking, prematurity low birth weight and APGAR (Appearance, Pulse, Grimace, Activity, Respiration) Scores (<5) are important. Different questionnaires are advised for children under the age of 3 years, older children and for specific risk groups (extremely preterm). In ophthalmological examination, eye movements, specially saccades, accommodation, crowding, contrast sensitivity and visual fields should be evaluated. OCT can show objective signs of trans-synaptic degeneration and abnormalities in fixation and saccades can be measured with eye tracking. Screening of visual perceptive functioning is recommended and can be directive for further assessment. MRI findings in CVI in Cerebral Palsy can be structured in five groups: Brain maldevelopment, white and gray matter lesions, postnatal lesions and a normal MRI. In children with CVI and periventricular leukomalacia, brain lesion severity correlates with visual function impairment. A differentiation can be made between cortical and subcortical damage and related visual function impairment. Additional assessments (neurological or genetic) can be necessary to complete the diagnosis of CVI and/or to reveal the etiology.

The speed acuity test as a diagnostic aid in cerebral visual impairment

One of the characteristics of children with cerebral visual impairments (CVI) is that they need more time to process visual information. However, currently, few tests are available that can reliably measure visual processing speed. The speed acuity test, a discrimination reaction-time test in which participants indicate the orientation of Landolt-C symbols as quickly and accurately as possible, was specifically developed to determine the time a child needs to discern visual details. The test measures both the accuracy and the latency of the responses for nine different optotype sizes in order to control for decreased visual acuity. The results show that children with CVI need significantly more time to respond to the largest optotype sizes than age-matched normally sighted children and children with visual impairments due to an ocular disorder (VI_o). This effect is independent of the time it takes to make a motor response. However, the reaction-time difference between the children with CVI and VI_o is not seen for optotype sizes at the acuity threshold. Together with reaction times on visual and auditory detection tasks as controls, reaction times measured in the speed-acuity test allow for acceptable discrimination (AUC in ROC analysis: 0.81) between CVI and VI_o.

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.

Viewing Strategies in Children With Visual Impairment and Children With Normal Vision: A Systematic Scoping Review

Viewing strategies are strategies used to support visual information processing. These strategies may differ between children with cerebral visual impairment (CVI), children with ocular visual impairment, and children with normal vision since visual impairment might have an impact on viewing behavior. In current visual rehabilitation practice a variety of strategies is used without consideration of the differences in etiology of the visual impairment or in the spontaneous viewing strategies used. This systematic scoping review focuses on viewing strategies used during near school-based tasks like reading and on possible interventions aimed at viewing strategies. The goal is threefold: (1) creating a clear concept of viewing strategies, (2) mapping differences in viewing strategies between children with ocular visual impairment, children with CVI and children with normal vision, and (3) identifying interventions that can improve visual processing by targeting viewing strategies. Four databases were used to conduct the literature search: PubMed, Embase, PsycINFO and Cochrane. Seven hundred and ninety-nine articles were screened by two independent reviewers using PRISMA reporting guidelines of which 30 were included for qualitative analysis. Only five studies explicitly mentioned strategies used during visual processing, namely gaze strategies, reading strategies and search strategies. We define a viewing strategy as a conscious and systematic way of viewing during task performance. The results of this review are integrated with different attention network systems, which provide direction on how to design future interventions targeting the use of viewing strategies to improve different aspects of visual processing.

Brain microstructural antecedents of visual difficulties in infants born very preterm

Infants born very preterm (VPT) are at risk of later visual problems. Although neonatal screening can identify ophthalmologic abnormalities, subtle perinatal brain injury and/or delayed brain maturation may be significant contributors to complex visual-behavioral problems. Our aim was to assess the micro and macrostructural antecedents of early visual-behavioral difficulties in VPT infants by using diffusion MRI (dMRI) at term-equivalent age. We prospectively recruited a cohort of 262 VPT infants (≤32 weeks gestational age [GA]) from five neonatal intensive care units. We obtained structural and diffusion MRI at term-equivalent age and administered the Preverbal Visual Assessment (PreViAs) questionnaire to parents at 3-4 months corrected age. We used constrained spherical deconvolution to reconstruct nine white matter tracts of the visual pathways with high reliability and performed fixel-based analysis to derive fiber density (FD), fiber-bundle cross-section (FC), and combined fiber density and cross-section (FDC). In multiple logistic regression analyses, we related these tract metrics to visual-behavioral function. Of 262 infants, 191 had both high-quality dMRI and completed PreViAs, constituting the final cohort: mean (SD) GA was 29.3 (2.4) weeks, 90 (47.1%) were males, and postmenstrual age (PMA) at MRI was 42.8 (1.3) weeks. FD and FC of several tracts were altered in infants with (N = 59) versus those without retinopathy of prematurity (N = 132). FDC of the left posterior thalamic radiations (PTR), left inferior longitudinal fasciculus (ILF), right superior longitudinal fasciculus (SLF), and left inferior fronto-occipital fasciculus (IFOF) were significantly associated with visual attention scores, prior to adjusting for confounders. After adjustment for PMA at MRI, GA, severe retinopathy of prematurity, and total brain volume, FDC of the left PTR, left ILF, and left IFOF remained significantly associated with visual attention. Early visual-behavioral difficulties in VPT infants are preceded by micro and macrostructural abnormalities in several major visual pathways at term-equivalent age.

Pathophysiological Heterogeneity of the BBSOA Neurodevelopmental Syndrome

The formation and maturation of the human brain is regulated by highly coordinated developmental events, such as neural cell proliferation, migration and differentiation. Any impairment of these interconnected multi-factorial processes can affect brain structure and function and lead to distinctive neurodevelopmental disorders. Here, we review the pathophysiology of the Bosch–Boonstra–Schaaf Optic Atrophy Syndrome (BBSOAS; OMIM 615722; ORPHA 401777), a recently described monogenic neurodevelopmental syndrome caused by the haploinsufficiency of NR2F1 gene, a key transcriptional regulator of brain development. Although intellectual disability, developmental delay and visual impairment are arguably the most common symptoms affecting BBSOAS patients, multiple additional features are often reported, including epilepsy, autistic traits and hypotonia. The presence of specific symptoms and their variable level of severity might depend on still poorly characterized genotype–phenotype correlations. We begin with an overview of the several mutations of NR2F1 identified to date, then further focuses on the main pathological features of BBSOAS patients, providing evidence—whenever possible—for the existing genotype–phenotype correlations. On the clinical side, we lay out an up-to-date list of clinical examinations and therapeutic interventions recommended for children with BBSOAS. On the experimental side, we describe state-of-the-art in vivo and in vitro studies aiming at deciphering the role of mouse Nr2f1, in physiological conditions and in pathological contexts, underlying the BBSOAS features. Furthermore, by modeling distinct NR2F1 genetic alterations in terms of dimer formation and nuclear receptor binding efficiencies, we attempt to estimate the total amounts of functional NR2F1 acting in developing brain cells in normal and pathological conditions. Finally, using the NR2F1 gene and BBSOAS as a paradigm of monogenic rare neurodevelopmental disorder, we aim to set the path for future explorations of causative links between impaired brain development and the appearance of symptoms in human neurological syndromes.

Age-Related Effects on the Spectrum of Cerebral Visual Impairment in Children With Cerebral Palsy

Background

Cerebral Visual Impairment (CVI) is a very common finding in children affected by Cerebral Palsy (CP). In this paper we studied the characteristics of CVI of a large group of children with CP and CVI, describing their neurovisual profiles according to three different age subgroups (subgroup 1: infants 6 months–2 years; subgroup 2: pre-school age 3–5 years; subgroup 3: school age ≥ 6 years).

Methods

We enrolled 180 subjects (104 males, mean age 66 ± 42.6 months; range 6–192 months) with CP and CVI for the study. We carried out a demographic and clinical data collection, neurological examination, developmental or cognitive assessment, and a video-recorded visual function assessment including an evaluation of ophthalmological characteristics, oculomotor functions, and basic visual functions. In school-aged children, we also performed an evaluation of their cognitive-visual profiles.

Results

There were signs of CVI in all the three subgroups. Subgroup 1 (62 children) and subgroup 2 (50 children) were different for fixation (p = 0.02), visual acuity (p = 0.03) and contrast sensitivity (p < 0.01), being more frequently impaired in younger children. Comparing subgroup 2 with subgroup 3 (68 children), the older children presented more frequently myopia (p = 0.02) while the younger ones esotropia (p = 0.02) and alteration in smooth pursuit (p = 0.03) and saccades (p < 0.01). Furthermore, fixation, smooth pursuit, visual acuity, contrast sensitivity and visual filed (p < 0.01) were more frequently impaired in younger children (subgroup 1) compared to the older ones. Multiple correspondence analysis (MCA) confirmed the different neurovisual profiles according to age: younger children with CP showed more signs of CVI compared to the older ones. 34 out of 68 children belonging to subgroup 3 underwent the cognitive visual evaluation; an impairment of cognitive visual skills was detected in 21 subjects.

Conclusion

Younger children with CP showed more signs of CVI compared to the older ones, likely for the physiological maturation of visual system and mechanisms of neuroplasticity. In this direction, we suggest an early neurovisual evaluation to detect any weak visual functions.

Workshops of the Eighth International Brain-Computer Interface Meeting: BCIs: The Next Frontier

The Eighth International Brain-Computer Interface (BCI) Meeting was held June 7-9th, 2021 in a virtual format. The conference continued the BCI Meeting series' interactive nature with 21 workshops covering topics in BCI (also called brain-machine interface) research. As in the past, workshops covered the breadth of topics in BCI. Some workshops provided detailed examinations of specific methods, hardware, or processes. Others focused on specific BCI applications or user groups. Several workshops continued consensus building efforts designed to create BCI standards and increase the ease of comparisons between studies and the potential for meta-analysis and large multi-site clinical trials. Ethical and translational considerations were both the primary topic for some workshops or an important secondary consideration for others. The range of BCI applications continues to expand, with more workshops focusing on approaches that can extend beyond the needs of those with physical impairments. This paper summarizes each workshop, provides background information and references for further study, presents an overview of the discussion topics, and describes the conclusion, challenges, or initiatives that resulted from the interactions and discussion at the workshop.

Neural correlates associated with impaired global motion perception in cerebral visual impairment (CVI)

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Cerebral visual impairment (CVI) is associated with impaired global motion processing.

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Mean motion coherence thresholds was higher in individuals with CVI.

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fMRI responses in area hMT+ showed an aberrant response profile in CVI.

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White matter tract reconstruction revealed cortico-cortical dysmyelination in CVI.

Cerebral visual impairment (CVI) is associated with a wide range of visual perceptual deficits including global motion processing. However, the underlying neurophysiological basis for these impairments remain poorly understood. We investigated global motion processing abilities in individuals with CVI compared to neurotypical controls using a combined behavioral and multi-modal neuroimaging approach. We found that CVI participants had a significantly higher mean motion coherence threshold (determined using a random dot kinematogram pattern simulating optic flow motion) compared to controls. Using functional magnetic resonance imaging (fMRI), we investigated activation response profiles in functionally defined early (i.e. primary visual cortex; area V1) and higher order (i.e. middle temporal cortex; area hMT+) stages of motion processing. In area V1, responses to increasing motion coherence were similar in both groups. However, in the CVI group, activation in area hMT+ was significantly reduced compared to controls, and consistent with a surround facilitation (rather than suppression) response profile. White matter tract reconstruction obtained from high angular resolution diffusion imaging (HARDI) revealed evidence of increased mean, axial, and radial diffusivities within cortico-cortical (i.e. V1-hMT+), but not thalamo-hMT+ connections. Overall, our results suggest that global motion processing deficits in CVI may be associated with impaired signal integration and segregation mechanisms, as well as white matter integrity at the level of area hMT+.

Exploratory Investigation of Brain MRI Lesions According to Whole Sample and Visual Function Subtyping in Children With Cerebral Visual Impairment

Background: There is limited research on brain lesions in children with cerebral visual impairment (CVI) of heterogeneous etiologies and according to associated subtyping and vision dysfunctions. This study was part of a larger project establishing data-driven subtypes of childhood CVI according to visual dysfunctions. Currently there is no consensus in relation to assessment, diagnosis and classification of CVI and more information about brain lesions may be of potential diagnostic value.

Aim: This study aimed to investigate overall patterns of brain lesions and associations with level of visual dysfunction and to compare the patterns between the classification subgroups in children with CVI.

Methods: School-aged children with CVI received ophthalmological and neuro-psychological/developmental assessments to establish CVI-related subtyping. Other pediatric information was collected from medical records. MRI scans were coded according to a semi-quantitative template including brain regions (right hemisphere, left hemisphere, visual pathways) and summed for total scores. Non-parametric analyses were conducted.

Results: 28 children had clinical brain MRI scans available [44% of total sample, Group A (lower severity of visual dysfunctions) n = 16, Group B (higher severity) n = 12]. Total brain scores ranged between 0 and 18 (Group A mdn = 7, IQR = 0.8–10.0, Group B mdn = 10, IQR = 6.5–11.8) and were widespread across regions. 71 per cent had post-geniculate visual pathway damage. The median total brain and hemisphere scores of Group B were higher than subgroup A but differences did not reach statistical significance. No statistically significant associations were found between brain scores and vision variables (acuity, contrast sensitivity).

Conclusion: This study found a spread of lesions across all regions on the brain scans in children with congenital CVI. The majority had damage in the postgeniculate visual pathways and visual cortex region suggesting this is an area of interest and potentially informative for diagnosis. However the subtyping classification did not show differences in number or region of lesions though the trend was higher toward Group B. This study confirms the complex diffuse and variable nature of brain lesions in children with congenital CVI, many of whom have other neurological impairments.

Structural and Functional Aspects of the Neurodevelopmental Gene NR2F1: From Animal Models to Human Pathology

The assembly and maturation of the mammalian brain result from an intricate cascade of highly coordinated developmental events, such as cell proliferation, migration, and differentiation. Any impairment of this delicate multi-factorial process can lead to complex neurodevelopmental diseases, sharing common pathogenic mechanisms and molecular pathways resulting in multiple clinical signs. A recently described monogenic neurodevelopmental syndrome named Bosch-Boonstra-Schaaf Optic Atrophy Syndrome (BBSOAS) is caused by NR2F1 haploinsufficiency. The NR2F1 gene, coding for a transcriptional regulator belonging to the steroid/thyroid hormone receptor superfamily, is known to play key roles in several brain developmental processes, from proliferation and differentiation of neural progenitors to migration and identity acquisition of neocortical neurons. In a clinical context, the disruption of these cellular processes could underlie the pathogenesis of several symptoms affecting BBSOAS patients, such as intellectual disability, visual impairment, epilepsy, and autistic traits. In this review, we will introduce NR2F1 protein structure, molecular functioning, and expression profile in the developing mouse brain. Then, we will focus on Nr2f1 several functions during cortical development, from neocortical area and cell-type specification to maturation of network activity, hippocampal development governing learning behaviors, assembly of the visual system, and finally establishment of cortico-spinal descending tracts regulating motor execution. Whenever possible, we will link experimental findings in animal or cellular models to corresponding features of the human pathology. Finally, we will highlight some of the unresolved questions on the diverse functions played by Nr2f1 during brain development, in order to propose future research directions. All in all, we believe that understanding BBSOAS mechanisms will contribute to further unveiling pathophysiological mechanisms shared by several neurodevelopmental disorders and eventually lead to effective treatments.

The Effect of Insight Questions Inventory and Visual Support Strategies on Carer-Reported Quality of Life for Children With Cerebral Palsy and Perceptual Visual Dysfunction in Nigeria: A Randomized Controlled Trial

Structured clinical history question inventories have previously been used to try and elicit symptoms of perceptual visual dysfunction (PVD) in children with cerebral palsy (CP) in different settings. Earlier studies have suggested that PVD may affect quality of life and specific habilitational strategies, linked to inventory responses, may improve quality of life. Through an RCT, based on a community based sample of children with CP in Cross River State, Nigeria, we aimed to determine if a structured history inventory such as the Insight question inventory (IQI) and associated tailored visual support strategies (IQI VSS) for the management of those children who have PVD, can improve quality of life and is superior to standard therapy. Children with CP were recruited by the key informant method and confirmed by clinical examination. The parent reported IQI was used to identify children with PVD. Primary outcome measures were both Pediatric Quality of Life 4.0 Generic (PedsQL 4.0 Generic) and Pediatric Quality of Life 3.0 Cerebral Palsy (PedsQL 3.0 CP) scale scores. Children were enrolled with a parallel arm allocation to either IQI and IQI VSS or to standard therapy for CP. Children were followed up for 6 weeks with weekly phone call session and the questionnaires repeated at the end of the 6 weeks’ period. Results show that the children in the treatment group (n = 191) showed no significantly different change between baseline and follow up in quality of life (PedsQL 4.0 Generic p = 0.943: and PedsQL-CP 3.0 p = 0.287), compared to the control group. There was suggestion of a better improvement (p = 0.035) in the PedsQL 3.0 CP subscale of speech and communication for the intervention group. The use of IQI VSS for the treatment of PVD in children with CP in this population does not show any superiority over current standard CP management in terms of overall quality of life. However, there was some evidence of improvement in quality of life in the area of speech and communication. Further research and refinement of these management method is required.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier [PACTR20161200188] 6396.

The relation between visual orienting functions, daily visual behaviour and visuoperceptual performance in children with (suspected) cerebral visual impairment

BACKGROUND

Children with cerebral visual impairment (CVI) present heterogeneous visual orienting functions (VOF) and higher-order perception. Multiple assessment methods evaluate CVI, but the relations between them remain unclear.

AIM

To investigate the relations between VOF and (1) daily life behaviour and (2) visuoperceptual tests in children with (suspected) CVI.

METHODS AND PROCEDURES

VOF were tested with a validated eye tracking-based paradigm. Visual perception was assessed using the children's visual impairment test for 3- to 6-year olds (CVIT 3-6) and (retrospective) visuoperceptual dimension results. Caregivers completed the Flemish cerebral visual impairment questionnaire (FCVIQ) and an expert panel scored relations between VOF and the other methods. We compared experts' survey responses with data-based results (linear mixed models and correlations).

OUTCOMES AND RESULTS

Fourty-four children (23 boys, 21 girls; median age = 7y11mo, SD = 2y7mo) participated. Twenty-one experts completed the survey. Slower VOF was significantly associated with (1) object and face processing impairments, (2) visual (dis)interest, (3) worse visual spatial perception (to local motion and form stimuli), and (4) worse CVIT 3-6 object and scene recognition (to cartoon stimuli).

CONCLUSIONS AND IMPLICATIONS

Integration of VOF with existing visual assessments provides a better clinical picture of CVI and can prevent misdiagnosing children as inattentive, incapable, or unmotivated.

The Developmental Eye Movement Test as a Diagnostic Aid in Cerebral Visual Impairment

The symptoms that characterize children with cerebral visual impairments (CVI) are diverse, ranging from extensive behavioral or physical disabilities to subtle changes that can easily be missed. A correct diagnosis of CVI is therefore difficult to make, but having a wide variety of tests available can be helpful. This study aims to determine if the developmental eye movement test (DEM) can be one of those tests. In this test, a fixed set of numbers has to be read aloud, first in vertical columns and then in horizontal lines. In order to measure differences between children with CVI compared to normally sighted age-matched controls and children with a visual impairment (VI), we determined DEM times, crowding intensities and the reaction time to a large visual stimulus for all three groups. We found that children with CVI or VI need significantly more time to read the DEM numbers than age-matched controls. Additionally, children with CVI need more time than children with VI to read the horizontal DEM, but not the vertical DEM. We also found a significant difference between the children with CVI and the other two groups in the relationship between horizontal DEM performance and crowding intensity. However, for the relationship between DEM performance and visual detection time, no group-differences were found. We conclude that the DEM can be a useful addition in the diagnosis of CVI, especially in combination with information about crowding.

Higher Visual Function Deficits in Children With Cerebral Visual Impairment and Good Visual Acuity

In clinical practice Cerebral Visual Impairment (CVI) is typically diagnosed by observation of abnormal visually guided behaviors which indicate higher visual function deficits (HVFDs) suggesting abnormal brain development or brain damage in a child with a suitable clinical history. HVFDs can occur even in the presence of good visual acuity and may remain undiagnosed because the good visual acuity does not prompt further investigation. This leads to a lack of understanding of the child's visual perceptual difficulties. In a prospective study, we determined the spectrum of HVFDs in a group of children with history suggestive of brain damage or disruption of brain development and an independent diagnosis of CVI in comparison with typically developing children with a structured 51 question inventory, the Higher Visual Function Question Inventory (HVFQI-51) adapted from the Cerebral Vision Impairment Inventory, CVI-I. Here, we show that the HVFQI-51 can detect a range of HVFDs in children with CVI with good visual acuity and clearly distinguishes these children from typically developing children. HVFDs in our study group could mostly be attributed to dorsal stream visual processing dysfunction though the spectrum varied between children. We report on the inclusion of the "not applicable" response option in analysis providing a picture of HVFDs more in tune with the overall disability of each child. We also propose a subset of 11 questions (Top-11) which discriminate between children with CVI vs. behaviors seen in typical children: this provides both a potential screening tool for initial assessment of HVFDs and a measure of CVI-related impairment, and needs further validation in a secondary independent sample.

Motion Processing Deficits in Children With Cerebral Visual Impairment and Good Visual Acuity

Purpose

We sought to characterize neural motion processing deficits in children with cerebral visual impairment (CVI) who have good visual acuity using an objective, quantifiable method (steady-state visual evoked potentials [SSVEPs]).

Methods

We recorded SSVEPs in response to three types of visual motion – absolute motion and more complex relative and rotary motion, comparing them to form-related vernier and contour responses. We studied a group of 31 children with CVI diagnosed via detailed clinical examinations and 28 age-matched healthy controls.

Results

Using measurements made at the appropriate response harmonics of the stimulation frequency, we found significant deficits in cerebral processing of relative and rotary motion but not of absolute motion in children with CVI compared with healthy controls. Vernier acuity, in keeping with good recognition acuity in both groups, was not different, nor were contour-related form responses.

Conclusions

Deficits for complex motion but relative sparing of elementary motion and form-related signals suggests preferential damage to extra-striate visual motion areas in children with CVI. The fact that these preferential losses occur in the absence of significant acuity loss indicates that they are not secondary to reduced visual acuity, but rather are an independent vulnerability in CVI. These results corroborate parental and caregivers’ reports of difficulties with tasks that involve motion perception in children with CVI.