Neuroimaging in children with congenital disorders of the peripheral visual system

Distance support and online intervention to blind and visually impaired children during the pandemic COVID-19

The COVID-19 pandemic imposed dramatic changes to everyone's daily routines, but especially to children with developmental disabilities. The Robert Hollman Foundation decided not to interrupt its service to all the visually impaired children and initiated a Distance Support Project. It was an online process covering all aspects of support for the children and involving audio-video calls, videos and tailored-made multisensory material created specifically for each child. A questionnaire, carried out after the 5-month project duration, was created to collect feedback from parents and professionals to understand the impact this project had on everyone involved. Overall both parents and professionals indicated high levels of satisfaction, but in a significant number of questions parents reported consistently higher levels of satisfaction (p-value <0.001). It was shown that parents felt reassured at this otherwise very difficult time because their children were able to continue their treatment, even if in a very different way. This fact encourages us to consider enriching our existing programmes of support and care, integrating this online approach when necessary. At the same time, it seems clear that the responses of the professionals indicate their belief that the benefits of the traditional ways of working remain of unquestionable importance for children with sight deprivation.

Autistic-Like Features in Visually Impaired Children: A Review of Literature and Directions for Future Research

There remains great interest in understanding the relationship between visual impairment (VI) and autism spectrum disorder (ASD) due to the extraordinarily high prevalence of ASD in blind and visually impaired children. The broad variability across individuals and assessment methodologies have made it difficult to understand whether autistic-like symptoms shown by some children with VI might reflect the influence of the visual deficit, or represent a primary neurodevelopmental condition that occurs independently of the VI itself. In the absence of a valid methodology adapted for the visually impaired population, diagnosis of ASD in children with VI is often based on non-objective clinical impression, with inconclusive prevalence data. In this review, we discuss the current state of knowledge and suggest directions for future research.

Autism in Children With Cerebral and Peripheral Visual Impairment: Fact or Artifact?

The aim of this study was to evaluate the occurrence and clinical characteristics of autism spectrum disorder in visually impaired children. In total, 273 participants, 214 with cerebral causes of vision impairment and 59 with peripheral causes, were assessed using multiple assessment methods and adapted for individuals with vision loss. We found that autism spectrum disorder was more prevalent in the visually impaired compared to general population, and that the prevalence varied according to the type of visual disorder (2.8% for cerebral and 8.4% for peripheral visual impairment). In subjects with cerebral visual impairment, the presence of autistic symptoms was consistent with the diagnosis of autism spectrum disorder. In children with peripheral visual impairment, certain symptoms related to visual loss overlapped with the clinical features of autism spectrum disorder, thus making clinical diagnosis more challenging. The development of assessment tools that take into account the type and level of visual impairment and validation testing in a larger population sample are needed in order to confirm these initial findings regarding the diagnosis of autism spectrum disorder in visually impaired children.

Combining visual sensory functions and visuospatial orienting functions in children with visual pathology: A longitudinal study

BACKGROUND

Peripheral and central visual processing development highly depends on the integrity of the visual sensory system and the allocation of visuospatial attention.

METHOD

We quantitatively followed visual sensory functions (VSF) and visuospatial orienting functions (VOF) over two years in 77 children (1-13 years) with different types of visual pathology.

RESULTS

Within the clinical groups, VSF were relatively constant over two years, except visual acuity, and VOF were characterized by longer reaction time, shorter fixation duration, and lower fixation accuracy than normal for their age. Children with peripheral pathology had high rates of abnormal VSF, of changes to abnormal visual acuity at 1-6 years, and larger and more abnormal VOF (fixation inaccuracy). Children with central pathology had relatively good VSF, whereas two-third had delayed orienting reaction times that differed from other groups mainly at 1-6 years.

CONCLUSION

The distinct patterns of quantitative VSF and VOF over time between the visual pathology groups, and the finding that both methods provided complementary information, argues for combining both types of assessments to provide comprehensive monitoring of visual functioning in children from a young age.

Functional vision and cognition in infants with congenital disorders of the peripheral visual system

AIM

To investigate how vision relates to early development by studying vision and cognition in a national cohort of 1-year-old infants with congenital disorders of the peripheral visual system and visual impairment.

METHOD

This was a cross-sectional observational investigation of a nationally recruited cohort of infants with 'simple' and 'complex' congenital disorders of the peripheral visual system. Entry age was 8 to 16 months. Vision level (Near Detection Scale) and non-verbal cognition (sensorimotor understanding, Reynell Zinkin Scales) were assessed. Parents completed demographic questionnaires.

RESULTS

Of 90 infants (49 males, 41 females; mean 13mo, standard deviation [SD] 2.5mo; range 7-17mo); 25 (28%) had profound visual impairment (light perception at best) and 65 (72%) had severe visual impairment (basic 'form' vision). The Near Detection Scale correlated significantly with sensorimotor understanding developmental quotients in the 'total', 'simple', and 'complex' groups (all p<0.001). Age and vision accounted for 48% of sensorimotor understanding variance. Infants with profound visual impairment, especially in the 'complex' group with congenital disorders of the peripheral visual system with known brain involvement, showed the greatest cognitive delay.

INTERPRETATION

Lack of vision is associated with delayed early-object manipulative abilities and concepts; 'form' vision appeared to support early developmental advance. This paper provides baseline characteristics for cross-sectional and longitudinal follow-up investigations in progress. A methodological strength of the study was the representativeness of the cohort according to national epidemiological and population census data.

Brain imaging studies in Leber's congenital amaurosis: new radiologic findings associated with the complex trait

Purpose

To report the incidence and new findings of abnormal brain imaging studies associated with patients initially diagnosed with Leber's congenital amaurosis (LCA) without definite systemic abnormalities and to determine the need for brain imaging studies in these patients.

Methods

A retrospective review of medical records was performed in 83 patients initially diagnosed as LCA and without definite systemic abnormalities before the age of 6 months in 2 tertiary referral centers. Brain magnetic resonance imaging was performed in 31 of 83 patients (37.3%).

Results

Six of 31 patients (19%) had radiologically documented brain abnormalities. Two patients had cerebellar vermis hypoplasia, 1 patient showed an absence of septum pellucidum, 2 subjects showed mild external hydrocephalus, and 1 patient was found to have a small cerebellum.

Conclusions

Approximately one fifth of the LCA patients in whom brain imaging was performed were associated with brain abnormalities, including the absence of septum pellucidum, which has not been documented in the literature. Brain imaging is mandatory in patients primarily diagnosed with LCA, even without definite neurologic or systemic abnormalities.

Social communication difficulties and autism spectrum disorder in young children with optic nerve hypoplasia and/or septo-optic dysplasia

AIM

the aim of this study was to study systematically social, communication, and repetitive/restrictive (SCRR) behavioural difficulties and clinical autism spectrum disorder (ASD) in children with optic nerve hypoplasia (ONH) and/or septo-optic dysplasia (SOD), and to investigate the relationship between visual impairment, SCRR difficulties, ASD, and cognition.

METHOD

a case-note study of clinic records from a specialist developmental vision service was completed. Standardized assessments of vision and development and clinician judgements about SCRR difficulties and clinical ASD were made by a multidisciplinary team.

RESULTS

a total of 45 females and 38 males (mean age 3y 5mo; range 10mo-6y 10mo) with ONH or SOD and profound visual impairment (PVI) or severe visual impairment (SVI) were assessed. A total of 58% of children had at least one SCRR difficulty, and 31% had a clinical diagnosis of ASD. The prevalence of ASD was slightly higher in children with SOD than in children with ONH (36% vs 26%) also slightly more frequent in children with PVI than in children with SVI (36% vs 27%). The prevalence of SCRR difficulties was statistically higher in children with PVI than in children with SVI (p=0.003). Clinical ASD was most likely to be diagnosed between 2 years 4 months and 4 years 6 months. Development was significantly delayed in children with ASD compared with children without social communication difficulties (p=0.001).

INTERPRETATION

children with SVI or PVI are at risk of SCRR difficulties and clinical ASD. Children with ONH and/or SOD and visual impairment have a similar risk of developing clinical ASD as other visual impairment groups. However, ASD prevalence data from this study are a minimum estimate, as some young children may have developed ASD behaviours in later childhood. Developmental surveillance for children with ONH and/or SOD should continue until at least the age of 4 years 6 months.

Social identity, autism and visual impairment (VI) in the early years

This article explores how visual impairment might impact on early social and emotional development including self-awareness and communication with others. Some children show a 'developmental setback' and other worrying developmental trajectories in the early years, including autistic related behaviours and autistic spectrum disorders. Research is beginning to reveal the risk factors and most vulnerable processes in the early years, including in social communication, joint attention and joint referencing. The new Developmental Journal for Visually Impaired Babies and Children draws on the research to date and provides a new framework for early intervention and habilitation.

Early support developmental journal for children with visual impairment: the case for a new developmental framework for early intervention

BACKGROUND

Congenital visual impairment has serious consequences for early development, particularly in those with the most profound impairment. Although there is individual variation, developmental delays and risks, including 'developmental setback', are widespread. There is no scientifically robust developmental framework grounded in contemporary theory and scientific knowledge to guide early intervention which may prevent or minimize the risk factors and developmental difficulties. The UK governmental initiative, Early Support, gave the impetus for developing a new developmental framework for babies and young children with visual impairment.

METHODS

This paper reports on the scientific literature that underpins the new framework and the limitations of existing intervention materials. The case for focusing on particular vulnerable areas and developing a new developmental framework, the Early Support Developmental Journal for babies and children with severe visual impairment, is presented.

CONCLUSIONS

The future direction for service delivery and evaluation is briefly described.

Retinal function in infants with optic nerve hypoplasia: electroretinograms to large patterns and photopic flash

AIMS

Optic nerve hypoplasia (ONH), which is defined as a congenital deficiency of retinal ganglion cells, may also involve more distal layers of the retina. We investigated electrophysiological function of the retina in ONH using electroretinograms (ERGs).

METHODS

ERGs were recorded from 48 subjects (3.5-35 months) with unilateral or bilateral ONH. Pattern reversal (4 degrees checks) was presented under chloral hydrate sedation, using an optical system to correct a cycloplegic refraction. A photopic flash stimulus was also used. Fundus photographs were used to measure the disk diameter/disk macula ratio (DD/DM), and to document other clinical signs. Eyes were classified as moderate (0.15-0.3) or severe (<0.15) ONH, and those with DD/DM greater than 0.3 were used as reference eyes.

RESULTS

Pattern ERG recording was completed in 89 eyes and was detectable in 80% of eyes with ONH (61/76 tested) and in all 13 reference eyes. Photopic flash ERGs were of good quality in all eyes. The severity of ONH correlates with the amplitude of the photopic flash b-waves and with the amplitude of the N95 component of the pattern ERG (P<0.01). However, the ERGs to large patterns were well preserved (>3.5 microV) in 10 of 35 eyes with severe ONH. Tortuous retinal vessels in eyes with either moderate or severe ONH were associated with smaller amplitude photopic b-waves and markedly diminished or undetectable pattern ERGs.

CONCLUSIONS

This study supports the hypothesis that retinal dysfunction distal to the ganglion cells is common in ONH, but is not predictable on the basis of ONH severity alone. Additionally, tortuous retinal vessels in ONH may be a sign associated with retinal dysfunction.

Association between visual impairment and functional and morphological cerebral abnormalities in full-term children

PURPOSE

To characterise the nature and degree of ocular disorders and cerebral morphological and functional abnormalities in a population-based group of visually impaired full-term pre-school children.

METHODS

Forty-five children who were born at full-term between 1989 and 1995 in Värmland, Sweden, were reported as being visually impaired. An ophthalmological examination was performed and clinical data regarding mental development and neurological disease were obtained for all children. Cerebral imaging was performed in 35 children.

RESULTS

Twenty-six per cent of the children were found to have ocular disorders only. Forty-two per cent had cerebral morphological abnormalities, verified by cerebral imaging, and 65% had signs of cerebral functional abnormalities. In total, 74% were found to have cerebral morphological and/or cerebral functional abnormalities.

CONCLUSION

The majority of children with visual impairment, including children with ocular disorders, were found to have cerebral morphological and/or cerebral functional abnormalities. We suggest that any child with visual impairment should therefore undergo cerebral imaging and be examined by a paediatrician in order to establish the correct diagnosis.