Advances in the evaluation and management of cortical/cerebral visual impairment in children

Cortical Visual Impairment in Childhood: 'Blindsight' and the Sprague Effect Revisited

The paper discusses and provides support for diverse processes of brain plasticity in visual function after damage in infancy and childhood in comparison with injury that occurs in the adult brain. We provide support and description of neuroplastic mechanisms in childhood that do not seemingly exist in the same way in the adult brain. Examples include the ability to foster the development of thalamocortical connectivities that can circumvent the lesion and reach their cortical destination in the occipital cortex as the developing brain is more efficient in building new connections. Supporting this claim is the fact that in those with central visual field defects we can note that the extrastriatal visual connectivities are greater when a lesion occurs earlier in life as opposed to in the neurologically mature adult. The result is a significantly more optimized system of visual and spatial exploration within the ‘blind’ field of view. The discussion is provided within the context of “blindsight” and the “Sprague Effect”.

Physician Prescribing and Referral Patterns in Children with Cerebral Visual Impairment

SIGNIFICANCE

Cerebral visual impairment (CVI) is the leading cause of visual impairment in the developed world. Providing children with CVI with the appropriate treatment ensures the best possible visual outcome and potentially improves quality of life.

PURPOSE

The purpose of this study was to determine physician prescribing and visual rehabilitation referral patterns in children with CVI.

METHODS

A retrospective chart review was completed on children with CVI examined at Cincinnati Children's Hospital Medical Center from January 1, 2008, to March 1, 2018. Significant refractive error warranting correction was determined using the American Academy of Ophthalmology Preferred Guidelines and the American Association for Pediatric Ophthalmology and Strabismus Vision Screening Committee Guidelines. The CVI Range was used as a surrogate to categorize CVI severity.

RESULTS

A total of 194 children were included. Sixty-eight (35%) had refractive error warranting correction and were prescribed glasses (group RC), 99 (51%) did not have refractive error warranting correction and were not prescribed glasses (group NRNC), 20 (10%) had refractive error warranting correction but were not prescribed glasses (group RNC), and 7 (4%) did not have refractive error warranting correction but were prescribed glasses (group NRC). There was greater than one-line Snellen equivalent difference between group RC (20/156) and group RNC (20/221). There was greater than six-line Snellen equivalent difference between group NRNC (20/149) and group NRC (20/35). Mean CVI Range score 2 values for each group were 5.9, 4.6, 4.8, and 7.1.

CONCLUSIONS

Children with less severe CVI were less likely to have significant refractive error but given glasses. Despite significant refractive error, children with more severe CVI were not prescribed glasses. Children with very low visual function were not prescribed glasses as frequently, possibly limiting their visual rehabilitation. Providers should ensure that all children with CVI are correctly prescribed glasses to provide the best possible visual outcome.

Ophthalmologic characteristics and outcomes of children with cortical visual impairment and cerebral palsy

BACKGROUND

Cortical visual impairment (CVI) is the most common cause of pediatric visual impairment in developed countries, and cerebral palsy (CP) is diagnosed in approximately half of children with CVI. It is unknown whether children with CVI who also have CP (CVI+CP) have different characteristics and outcomes (with regard to visual acuity, strabismus, and response to strabismus surgery) than children with CVI without CP (CVI-CP).

METHODS

The medical records of all children with CVI, with and without CP, evaluated at our institution between 2013 and 2019 were retrospectively reviewed. Presentation and outcomes of children with CVI+CP were compared to those with CVI-CP.

RESULTS

A total of 151 children with CVI+CP and 153 children with CVI-CP were included. Children with CVI+CP were more likely to be diagnosed with significant refractive error (53.6% vs 41.2%; P = 0.03), optic atrophy (46.4% vs 32.7%; P = 0.01), and strabismus (82.8% vs 72.5%; P = 0.03) at presentation. Good ocular alignment after strabismus surgery was achieved in 30% of children with CVI+CP and 63.6% of children with CVI-CP (P = 0.48). Of 9 children with long-term (≥8 years) postoperative follow-up, 100% of CVI-CP patients achieved good outcomes compared with 0% of CVI+CP patients (P = 0.0079). Visual acuity at presentation and the percentage of patients who experienced improvement in visual acuity did not differ between groups.

CONCLUSIONS

In our study cohort, children with CVI+CP had a higher likelihood of ophthalmic comorbidities and may have worse long-term strabismus surgery outcomes than children with CVI-CP.

Methods of visual assessment in children with cortical visual impairment

PURPOSE OF REVIEW

Cortical visual impairment (CVI) is the leading cause of pediatric visual impairment in developed countries. Currently, there is no standardized method of visual assessment in these children, who usually cannot participate in tests designed for typically developing children. A reproducible method of visual assessment that accurately reflects the multitude of visual deficits in CVI is critical to evaluate proposed therapies for this disorder. This review analyzes current research on methods of visual assessment in children with CVI.

RECENT FINDINGS

Earlier studies focused on measuring visual acuity in children with CVI. More recent studies have emphasized other aspects of visual function, such as contrast sensitivity, motion detection, and visual search. Current research topics include questionnaires, functional vision assessment (CVI Range), neuropsychological tests of visual perception, and eye tracking. Eye tracking shows promise for visual assessment in both clinical and research settings because it is objective and quantitative, with the ability to assess diverse visual parameters.

SUMMARY

Current research on visual assessment in children with CVI focuses on measuring deficits of visual function beyond visual acuity. This research represents an important step toward designing clinical trials to identify effective therapeutics for this increasingly prevalent disorder with heterogeneous manifestations.

Creating a Path for Systematic Investigation of Children With Cortical Visual Impairment Who Use Augmentative and Alternative Communication

Purpose There is limited information about how to support children with cortical visual impairment (CVI) who require augmentative and alternative communication (AAC). An initial review designed to explore the available evidence was used to outline critical needs in moving research and intervention forward for children who use AAC and have CVI. Method Previous systematic reviews, six databases, and theses and dissertations were systematically searched, along with reviews of the resulting works cited. An initial yield of 575 articles was narrowed to 10, which discussed AAC interventions that included children with CVI. Results Three interventions were technology based, and seven were instructional based. The use of textured microswitches was the most frequent form of technology intervention, with the frequency of switch activations being the most frequently coded outcome. Overall, the studies represent explorations in the area rather than systematic lines of inquiry. Conclusions While evidence shows at least some children with CVI have been included in AAC research to date, the inclusion is more incidental than deliberate. Issues such as clear descriptions of the vision capabilities and needs of participants may have impacted study results.

The application of magnetic resonance imaging and diffusion-weighted imaging in the diagnosis of hypoxic-ischemic encephalopathy and kernicterus in premature infants

BACKGROUND

To explore the application of magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in the diagnosis of hypoxic-ischemic encephalopathy and kernicterus in premature infants.

METHODS

Fifty-eight premature infants with hypoxic-ischemic encephalopathy and fifty-eight premature infants with kernicterus who were examined and treated in our hospital between January 2018 and January 2021 were assigned to the observation group or the control group. All patients were examined by MRI imaging and DWI imaging, and the examination results were compared between the two groups.

RESULTS

No significant differences were found in sensitivity, specificity, positive predictive value, or negative predictive value between the observation group and the control group (P>0.05). MRI could clearly visualize the signal changes of patients, whereas DWI did not show any signal changes. There was no significant difference between MRI and DWI in the diagnosis of hypoxic-ischemic encephalopathy in premature infants. Further, there was no significant difference in the diagnostic performance of MRI between the observation group and the control group (P>0.05). However, the diagnostic performance of DWI in the control group was better than that in the observation group, and the difference was statistically significant (P<0.05).

CONCLUSIONS

MRI and DWI imaging have high detection rates for the diagnosis of hypoxic-ischemic encephalopathy and kernicterus in premature infants. These imaging methods can benefit the treatment of premature infants and have important clinical application value.

Visual assessment of preterm and full-term infants under the age of 12 months using the Preverbal Visual Assessment questionnaire

BACKGROUND

Infants develop many complex visual competences within the first 12 months of life. Premature infants are at high risk for abnormal visual and neurological development. Clinical medical history or neurologic evaluation do not give enough information on visual maturation in infants under 12 months of age.

AIMS

To compare visual maturation between preterm and full-term infants aged under 12 months, using the Preverbal Visual Assessment questionnaire (PreViAs).

STUDY DESIGN

Retrospective cross-sectional analysis.

SUBJECTS

Infants aged under 12 months, who visited our rehabilitation department for early intervention. Infants were categorized as either preterm or full-term, and assigned to one of three subgroups (0-4 months, 4-8 months, 8-12 months) according to corrected or chronological age.

OUTCOME MEASURES

PreViAs scores.

RESULTS

There were 200 preterm and 225 full-term infants analyzed. The mean global PreViAs scores among preterm infants were significantly lower than among full-term infants in all age groups (0-4 months: p = 0.033, 4-8 months: p = 0.005, and 8-12 months: p = 0.008). The mean global scores and four subdomain scores of the PreViAs were significantly lower (p < 0.001) in very preterm (under 32-weeks gestational age) and very low birth weight (under 1500 g birth weight) than in moderate-to-late preterm infants (between 32- to 37- weeks gestational age) and infants with birth weight above 1500 g. Patent ductus arteriosus, retinopathy of prematurity, and birth weight (percent) showed significant correlation with PreViAs global scores.

CONCLUSION

PreViAs is a useful tool for visual assessment of infants under 12 months, especially in high-risk infants.