Identifying and characterising cerebral visual impairment in children: a review

Assessing visual mental imagery abilities in cerebral visual impairment

Visual imagery refers to the ability to create voluntary mental representations in the absence of corresponding visual stimuli, and current evidence suggests that it shares common neural mechanisms with visual perception. Cerebral visual impairment (CVI) is a brain-based visual disorder caused by early neurological injury and maldevelopment of central visual processing pathways and areas. Individuals with CVI often present with a complex visual profile, including deficits related to higher-order visual processing. However, the impact of visual maldevelopment on imagery abilities in this population has not been extensively characterized. We used the Vividness of Visual Imagery Questionnaire (VVIQ) to investigate visual imagery abilities in a cohort of CVI participants (n = 25, mean age = 22.48 years ± 12.31 SD) compared to controls with neurotypical vision and development (n = 25, mean age = 22.88 years ± 4.94 SD). We found that individuals with CVI had significantly lower VVIQ scores (mean = 41.84 ± 18.61 SD) than controls (mean = 62.48 ± 13.07 SD), after controlling for age and verbal IQ level. Within the CVI group, visual imagery abilities were not significantly different when separated by baseline visual acuity, gestational status, or co-occurrence of autism spectrum disorder. These results suggest that impaired visual imagery may represent an important feature characterizing the complex visual profile of CVI.

Cerebral/Cortical Visual Impairment Classification and Categorization Using Eye Tracking Measures of Oculomotor Function

Purpose

Cerebral/cortical visual impairment (CVI) is a leading cause of pediatric visual impairment and is frequently associated with abnormal ocular motility. Eye tracking has previously been used to characterize oculomotor function in CVI. The purpose of this study was to evaluate the utility of eye tracking in diagnosis, categorization, and prognostication of CVI.

Design

Prospective longitudinal study.

Participants

Thirty-nine children with CVI and 41 age-matched controls.

Methods

Children with CVI underwent 4 eye tracking sessions over 1 year, and age-matched controls completed 1 eye tracking session. Fixations and saccades were labeled by the eye tracking software and used to compute 9 oculomotor features. In children with CVI, unsupervised data-driven clustering analysis using these 9 features was performed to identify 3 CVI eye tracking oculomotor groups. Clinical and demographic characteristics of eye tracking oculomotor groups were compared.

Main Outcome Measures

(1) Area under the curve (AUC) for eye tracking oculomotor features in classifying patients with CVI and controls; (2) differences between 3 CVI eye tracking oculomotor groups on clinical and demographic characteristics; and (3) change in visual acuity (VA) over 1 year in 3 CVI eye tracking oculomotor groups.

Results

Six oculomotor features (fixation and saccade latency, frequency, and off-screen proportion) had an AUC ≥0.90 in classifying children with CVI and controls (P < 0.0001). Cerebral/cortical visual impairment eye tracking oculomotor groups had significantly different VA (P < 0.0001) and change in VA over 1 year (P = 0.049). Patients in group B, who had the greatest improvement in VA, were younger and had higher rates of term hypoxic ischemic encephalopathy.

Conclusions

Eye tracking measures of oculomotor function accurately distinguish between children with CVI and age-matched controls. Clustering analysis revealed 3 CVI eye tracking oculomotor groups with prognostic significance. Eye tracking shows promise as an objective, quantitative measure of oculomotor function in CVI that may in future be useful in both clinical practice (for longitudinal assessment, prognostication, and guiding individualized interventions) and research (as an outcome measure or method to stratify patients in clinical trials).

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The relation between clutter and visual fatigue in children with cerebral visual impairment

PURPOSE

Cerebral visual impairment (CVI) is a brain-based condition which can be exacerbated by clutter. This study aimed to explore the relation between clutter and visual fatigue in children with CVI and evaluate the effectiveness of clutter algorithm metrics in assessing visual clutter in photographs of children's play areas and the relation to visual fatigue.

METHODS

Visual clutter was measured using algorithmic metrics, subjective observations by a clinical researcher (who also observed visual fatigue) and a Qualtrics survey.

RESULTS

Seventy-two children (mean performance age = 7 years 4 months) were included. Visual fatigue was present in over 90% of children. Results revealed a relation between clutter and visual fatigue observations (rs = 0.29; p = 0.01) and between visual clutter observations from researchers and Qualtrics participants (rs = 0.32; p = 0.02). Certain metrics were correlated with visual clutter observations (rs ranging from -0.30 to 0.51, p-values ranging from <0.001 to 0.03), but not with visual fatigue.

CONCLUSIONS

Children with CVI presented with visual fatigue, particularly in cluttered environments. Therefore, parents, caregivers, teachers and clinicians should be attentive to visual fatigue signs, as early recognition and intervention can help address the child's needs more effectively. Algorithms that effectively quantify visual clutter are valuable tools that can be integrated to enhance the assessment of clutter and its relation with visual fatigue to advance CVI research methodology. However, a clinician is required to assess visual fatigue and to obtain detailed information on environmental clutter, which algorithms alone may not fully capture. Finally, we recognise that visual fatigue and the impact of clutter should be integrated into psychoeducation and the comprehensive assessment of individuals with CVI.

Sensory substitution and augmentation techniques in cerebral visual impairment: a discussion of lived experiences

Pediatric vision loss due to cerebral visual impairment (CVI) is an urgent public health issue, demanding evidence-based (re)habilitation and educational strategies. As with other neurodiverse populations, research on CVI needs to be directly informed by the lived experiences of those affected-children, adults, and their families. In this paper, three individuals with early-onset CVI and two parents discuss sensory substitution and augmentation developed in childhood in the absence of early identification of CVI, and they detail the important impact of the empowering, professionally taught non-visual skills-such as braille, orientation and mobility training, and assistive technology-which were acquired later. Efforts to improve visual perception ability and understanding of the visual world, both effective and ineffective, were made through traditional, professionally administered vision therapy, self-taught coping strategies, and from intensive arts participation. The authors discuss the strategies they use to leverage senses other than vision to achieve their daily life, educational, social, and career goals. Nonvisual skills training effective in those with ocular blindness, though received later in life after the delayed diagnosis, proved to be indispensable for these authors' who have CVI access to all aspects of independent life. It is our hope that these personal experiences may encourage research into how traditional nonvisual skills training used for the ocularly blind, as well as sensory substitution and augmentation techniques, may be used to develop evidence-based multidisciplinary interventions; improved academic and independent life skills; multisensory educational and therapeutic interventions; and successful integration into the community for all CVIers.

'We don't know nearly enough': an online survey exploring perspectives of specialists who support children with brain-based visual impairments

Introduction

Children with brain-based visual impairments (some of whom have a diagnosis of Cerebral Visual Impairment, or 'CVI') represent a growing and underserved population within vision services. These children often have more complex needs than those with ocular visual impairments and benefit from specialist support from multiple disciplines. This study aimed to understand the perspectives of these specialists in terms of their goals, views on collaboration, and understanding of the term 'CVI'.

Methods

We invited a range of specialists who work with children with brain-based visual impairments, including educators, rehabilitation staff, clinicians, and family members, to complete an online survey between April 2023 and April 2024.

Results

The analysis included 94 respondents: 51 educators, 30 rehabilitation staff, 7 clinicians, and 6 family members. Respondents shared common goals of connecting with the child (87/94, 93%) and fostering their learning and development (82/94, 93%). However, respondents also noted some specific and divergent goals, which can be at odds with each other. Professional staff frequently identified family members as the most valuable source of information about their child's vision (36/88, 41%), though family members expressed feeling under-valued. Transdisciplinary clinics were highlighted as a helpful model to provide quality child-centered care. Of the 73 professional staff who reported being familiar with the term 'CVI' (73/88, 83%), most (61/73, 84%) thought it was underdiagnosed, but respondents had different perspectives on what a diagnosis meant. Only 73% of professionals familiar with CVI reported receiving formal training about it.

Discussion

The varied goals and different perspectives on CVI create challenges to providing cohesive support for children with brain-based visual impairments. Increasing the availability of complementary formal training across disciplines and adopting transdisciplinary models of care are promising approaches to improve the quality of services.

The development of a screener for Cerebral Visual Impairment

This study explored the secondary use of Luxembourg's school monitoring tool for a large-scale screening of Cerebral Visual Impairment (CVI)-related difficulties. 44 items, with and without time constraint, were developed, and pretested among 959 children. All children subsequently participated in an individual evaluation of higher-level visual processing (HLVP) measures related with CVI. A clinical outcome was attributed post hoc with 32 children being classified as having CVI-related difficulties. To explore the predictive power of the CVI items included in the monitoring, item responses were matched to the results of the individual HLVP assessment. Of all items, the untimed item targeting the combined functions of surface and rotation significantly distinguished group performances (<.05). To improve condition discrimination, different item combinations were tested. Sensitivity and specificity metrics were computed resulting in ranges of 37.5% - 81.3% and 27% - 88.8% respectively. The item combination with the highest sensitivity (81.3%) was retained considering a viable trade-off between sensitivity and specificity metrics. These results support the secondary use of an existing large-scale monitoring tool to screen for CVI-related difficulties in the beginning of elementary school, provided that additional sources of information are progressively implemented to strengthen the tool's predictive power.

How do children with Cerebral Visual Impairment (CVI)-related visual difficulties perform on key academic domains in grade 1?

Previous research estimated a prevalence of 3.4% Cerebral Visual Impairment (CVI)-related visual problems within primary school children, potentially compromising students' performance. This study aimed to clarify how CVI-related visual difficulties relate to academic performance in standardized achievement tests. As part of the Luxembourg school monitoring programme, 1129 first graders (mean age of 7 years) participated in three competence tests (mathematics, early literacy and listening comprehension) and in student and parent questionnaires (background information). The same children took part in a CVI-related visual difficulties screening (Evaluation of Visuo-Attentional abilities battery, optometric and orthoptic measures). The sample was divided post-screening into 38 children with potential CVI-related visual difficulties (18 females, 20 males, mean age 7y, range 6-8y) and 890 typically developing (TD) children (445 females, 430 males, 15 missing, mean age 7y, range 5-10y). Compared to the TD sample children with CVI-related visual difficulties significantly underperformed in early literacy and mathematics, but not in listening comprehension, even when controlling for background characteristics known to influence performance (gender, socio-economic status, migration background, parental education, home language, age). The results confirm the association of CVI-related visual difficulties with learning processes already at primary school level and emphasize the need to implement a systematic screening for CVI-related visual difficulties, as early as possible within the school path, to ensure adequate measures are employed to aid students at risk.

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.

Gestalt, Navon and Kanizsa illusion processing in CVI, ADHD, and dyslexia Children with Normal verbal IQ

Introduction

Global Visual Selective Attention (VSA) is the ability to integrate multiple visual elements of a scene to achieve visual overview. This is essential for navigating crowded environments and recognizing objects or faces. Clinical pediatric research on global VSA deficits primarily focuses on autism spectrum disorder (ASD). However, in children with cerebral visual impairment (CVI) and other neurodevelopmental disorders (ADHD, dyslexia) similar deficits are reported. The aim of this study was to investigate global VSA performance in children with CVI, ADHD, dyslexia and neurotypical children by combing gaze-based measures with conventional neuropsychological tasks.

Methods

We included children aged 6-12 years with CVI (n = 20), ADHD (n = 30), dyslexia (n = 34) and neurotypical development (n = 37), all with normal verbal IQ. Eye tracking measurements were stepwise introduced within three global VSA tasks: Gestalt Closure (no eye tracking), Navon stimuli (eye tracking-based qualitative analysis) and Kanizsa Illusory Contours (KIC; eye tracking-based quantitative analysis). Verbal responses were compared with non-verbal gaze behavior.

Results

Children with CVI had significantly lower success rates on Gestalt Closure recognition, prolonged verbal response times on Navon stimuli, and decreased verbal and gaze performance on the KIC task compared to all other groups, irrespective of visual acuity. Children with ADHD and dyslexia performed similar to neurotypical children on all tasks.

Discussion

The results suggest а distinct global VSA deficit in children with CVI, which aligns with clinical observations of symptoms in daily life. Incorporating gaze-based analyses provided new information about search strategies beyond verbal answers and made the KIC task more inclusive for children with language and motor disabilities. Assessing global VSA within clinical CVI assessments could improve the differential diagnostic evaluations among children with CVI, ADHD and dyslexia, leading to more personalized treatment approaches.

Special Commentary: Cerebral/Cortical Visual Impairment Working Definition: A Report from the National Institutes of Health CVI Workshop

Cerebral/cortical visual impairment (CVI), a brain-based condition, has emerged as a leading cause of pediatric visual impairment in the United States and other industrialized nations. The National Eye Institute (NEI) recognized CVI as a priority area for research as part of their 2021 NEI Vision for the Future Strategic Plan and partnered with the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Neurologic Disorders and Stroke within the National Institutes of Health (NIH) to sponsor a CVI Workshop in November 2023. A panel consisting of a group of clinicians with expertise in diagnosing CVI convened to draft a working definition for this condition. Five key elements were identified: (1) CVI encompasses a spectrum of visual impairments caused by an underlying brain abnormality that affects the development of visual processing pathways and is characterized by deficits in visual function and functional vision; (2) the visual dysfunction in CVI is greater than expected by any comorbid ocular conditions alone; (3) the visual dysfunction in CVI may manifest as lower-order or higher-order afferent visual deficits, or both, leading to characteristic behaviors in affected individuals; (4) although CVI may be comorbid with other neurodevelopmental disorders, CVI is not primarily a disorder of language, learning, or social communication; and (5) the underlying neurologic insult of the developing brain may go unrecognized or undiagnosed until later in life. Future work is needed to achieve consensus on nomenclature, diagnostic criteria, and strategies for early identification and intervention. The NIH is developing a CVI registry to collect relevant demographic and clinical data prospectively and longitudinally to help inform future research questions and to provide insight into considerations for future clinical trials in the field of CVI.

Hiding in plain sight: children with visual perceptual difficulties in schools

Cerebral visual impairment (CVI) is increasingly being recognized as a significant cause of visual difficulties in children, particularly those with typical visual acuity, who nonetheless struggle in educational settings. This narrative review aims to elucidate the nature and impact of visual perceptual difficulties (VPD) associated with CVI in school-aged children, who often remain undiagnosed due to the current erroneous focus on visual acuity as a required diagnostic criterion for CVI. The review synthesizes findings from recent studies, highlighting that up to 3.4% of children in mainstream schools and a higher percentage in special educational settings may experience VPD, which significantly impacts upon their learning and development. The manifestations of VPDs, such as difficulties in motion perception, recognition, and visuospatial processing, are often subtle and can thus be overlooked, leading to misconceptions about the origins of the affected child's abilities and behaviors. The review also discusses the challenges in current diagnostic processes, emphasizing the need for comprehensive history taking and assessments that go beyond standard visual acuity tests. It proposes a multi-faceted approach to identification and support, incorporating both clinical assessments and teacher/parental observations, to better address the needs of affected children. Furthermore, this paper advocates for the inclusion of VPDs in the International Classification of Diseases (ICD 11) to ensure children with these visual issues receive appropriate educational support. By integrating lived experiences of individuals with CVI and the latest research findings, this review underscores the urgent need for awareness and tailored educational strategies designed to support children with VPDs. The findings suggest that without such recognition and intervention, many children with VPDs will continue to "hide in plain sight," facing unnecessary challenges in their educational and social development. The review concludes with recommendations for policy changes and future research directions to improve the identification, classification, and support of children with VPDs within the educational system.

An evaluation of health-related quality of life and its relation with functional vision in children with cerebral visual impairment

BACKGROUND

Health-related Quality of Life (HRQOL) and its relation with functional vision is understudied in cerebral visual impairment (CVI).

AIMS

Characterising HRQOL, comparing child self- and parent proxy-reports, and exploring relations with functional vision.

METHODS AND PROCEDURES

Seventy-three children with CVI (n females = 33; n males = 40; Mean performance age = 7y2m) were included. HRQOL was measured with Pediatric Quality of Life Inventory (PedsQL) child self- and parent proxy-reports and compared using Wilcoxon signed-rank tests. Risk for impaired HRQOL was evaluated using cut-off scores. Parents scored functional vision using the Insight Questions Inventory and the Flemish CVI Questionnaire.

OUTCOMES AND RESULTS

61 % (self-reported) or 66 % of children (proxy-reported) were at-risk for impaired total HRQOL. Ratings were correlated (rs = 0.305; p = 0.013); however, children rated higher total HRQOL compared to parent-proxy (r = 0.382; p = 0.002). The Insight Questions Inventory and the PedsQL proxy-report were correlated (rp = -0.454; p < 0.001), the Flemish CVI Questionnaire was negligibly correlated (rp = -0.244; p = 0.041).

CONCLUSIONS AND IMPLICATIONS

HRQOL is reduced in CVI, and both child and parent perspectives are crucial. HRQOL and functional vision are intricately related, and impairment in one negatively affects the other.

Reorganization of integration and segregation networks in brain-based visual impairment

Growing evidence suggests that cerebral connectivity changes its network organization by altering modular topology in response to developmental and environmental experience. However, changes in cerebral connectivity associated with visual impairment due to early neurological injury are still not fully understood. Cerebral visual impairment (CVI) is a brain-based visual disorder associated with damage and maldevelopment of retrochiasmal pathways and areas implicated in visual processing. In this study, we used a multimodal imaging approach and connectomic analyses based on structural (voxel-based morphometry; VBM) and resting state functional connectivity (rsfc) to investigate differences in weighted degree and link-level connectivity in individuals with CVI compared to controls with neurotypical development. We found that participants with CVI showed significantly reduced grey matter volume within the primary visual cortex and intraparietal sulcus (IPS) compared to controls. Participants with CVI also exhibited marked reorganization characterized by increased integration of visual connectivity to somatosensory and multimodal integration areas (dorsal and ventral attention regions) and lower connectivity from visual to limbic and default mode networks. Link-level functional changes in CVI were also associated with key clinical outcomes related to visual function and development. These findings provide early insight into how visual impairment related to early brain injury distinctly reorganizes the functional network architecture of the human brain.

Impaired Visuospatial Processing in Cerebral Visual Impairment Revealed by Performance on a Conjunction Visual Search Task

Cerebral visual impairment (CVI) is a brain-based visual disorder associated with injury and/or maldevelopment of central visual pathways. Visuospatial processing impairments are a cardinal feature of the complex clinical profile of individuals with CVI. Here, we assessed visuospatial processing abilities using a classic conjunction search task. Twenty-three (23) individuals previously diagnosed with CVI (mean age 18.55 years ± 4.98 SD) and 37 controls with neurotypical development (mean age 21.11 years ± 4.56 SD) participated in the study. Subjects were instructed to search for a two-feature target (a white or black letter "O" or "C") presented among a varying number of surrounding distractors (set sizes ranging from 1 to 32 items). Behavioral outcomes collected were reaction time (RT), accuracy, as well as slope and intercept values derived from the RT x set size function. Overall, participants with CVI took longer and were less accurate in finding the target than controls. Analysis of RT x set size functions revealed a profile consistent with less efficient search and slower visual orienting responses as indexed by higher slope and intercept values, respectively. These results are consistent with clinical reports of impaired visuospatial processing abilities and deployment of visual selective attention in individuals with CVI.

Quality of life and functional vision in adolescents with surgically treated hydrocephalus in infancy

AIM

To evaluate health- and vision-related quality of life (HR- and VR-QoL) and perceptual visual dysfunction (PVD) in adolescents with hydrocephalus surgically treated in infancy.

METHODS

In total, 23 adolescents (15 males and 8 females; median age 14.9 years) with hydrocephalus and 31 controls were evaluated using validated instruments to measure HR-QoL and VR-QoL. PVDs were reported by history taking in five areas: recognition, orientation, depth, movement and simultaneous perception.

RESULTS

Adolescents with hydrocephalus and the parent proxy reports showed lower mean total Paediatric Quality of Life Inventory 4.0 scores (75.8 and 63.7, respectively) compared with controls (87.6 and 91.5), p = 0.016 and p < 0.0001. Parent-reported scores were lower than self-reported scores (p = 0.001). Adolescents with myelomeningocele (n = 10) showed lower physical health scores (p = 0.001). No VR-QoL difference was found between groups. PVDs were reported in ≥1 area by 14/23 hydrocephalus participants and 2/31 controls (p < 0.0001). Associations were found in the hydrocephalus group between VR-QoL and HR-QoL (rs = 0.47, p = 0.026) and number of PVD areas (rs = -0.6, p = 0.003).

CONCLUSION

Adolescents with hydrocephalus and their parents reported lower HR-QoL and more PVDs. These problems indicate the need for not only ophthalmological follow-ups but also evaluation of QoL and PVDs in individuals with infantile hydrocephalus.

Correlation of optic nerve on magnetic resonance imaging with visual acuity in children with cerebral visual impairment

AIM

The aim of the study was to correlate the optic nerve dimensions at various locations on magnetic resonance imaging (MRI) with the visual acuity of children with cerebral visual impairment (CVI).

MATERIALS AND METHODS

A 1-year cross-sectional study was conducted in a tertiary care hospital involving 60 children aged 1 to 12 years diagnosed with CVI but without ocular pathologies. Visual acuity was evaluated using teller acuity cards (TACs). MRI of the brain and orbit was performed using three-dimensional high-resolution, volumetric heavily T2-weighted sequences to screen for brain pathologies and measure optic nerve dimensions at two locations. The correlation between visual acuity and optic nerve dimensions was analyzed. The Chi-square test was employed to assess significance using SPSS software.

RESULTS

In our study, 64% (n = 38) of the participants were children under 3 years of age. The severity and characteristics of CVI influenced visual functioning at different ages. As children with CVI grew older and moved from Phase I to Phase III, the proportion with very low visual acuity significantly decreased from 85.2% in Phase I to 22.2% in Phase III and from 63.2% in the <3-year age group to 18.2% in more than 5-year age group. No direct correlation was found between optic nerve dimensions and visual acuity but optic disc changes such as optic disc pallor significantly correlated with low visual acuity.

CONCLUSION

Our findings suggest that there may not be a direct correlation between optic nerve dimensions and visual acuity in children with CVI. However, optic disc changes do correlate with visual acuity, but optic disc changes alone are not a criterion for assessing visual function. Additionally, our study highlights the significance of a combined assessment by a neuro- ophthalmologist and neuro-pedaitrician in children with CVI.

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.

The Impact of Cerebral Visual Impairment on Social Skills and Sensory Processing

Limited evidence exists on the impact of cerebral visual impairment (CVI) on developmental domains in toddlers. This study investigated whether CVI influences social skills and sensory processing in toddlers with cerebral palsy (CP). The study included toddlers with CP, with or without CVI, and typically developing (TD) toddlers. All parents completed the demographic information form. Social skills were assessed by the Brief Infant-Toddler Social and Emotional Assessment (BITSEA). Sensory processing was evaluated by the Infant/Toddler Sensory Profile (ITSP). Analysis of covariance was employed to assess the disparity in BITSEA and ITSP scores. Toddlers with CP and CVI group demonstrated lower social competence than the other groups (p < .05). Having CVI did not cause a statistically significant difference in sensory processing among toddlers with CP (p > .05). CVI significantly affects social competence in toddlers with CP but does not affect sensory processing.

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.

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.

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.