A brain-based approach to identifying and treating cerebral visual impairment in children
In this project we aim to quantify residual visual function in children and adolescents who have suffered brain damage early in their development. This type of vision loss, called cerebral visual impairment (CVI), is the leading cause of childhood sight loss in the developed world. Currently, diagnosis and treatment are overly reliant on observed patterns of behavior and generalized assessments [Chang & Borchert, 2020].
We will use brain imaging to quantify structural and functional loss to provide an objective measure of sight loss and guide rehabilitative strategies. As with stroke patients, there is often a mismatch between the observed symptoms and underlying residual anatomy and brain function: many different patterns of damage may lead to similar assessment outcomes [Papanikolaou et al, 2014]. In fact, it is becoming increasingly apparent that the optimal treatment approach for each child with CVI may be unique.
-- Background --
Around 50% of the entire human neocortex is given over to the analysis of visual information. Therefore, damage to the brain in early childhood invariably has visual consequences. It is estimated that between 30-40% of all children with visual impairment in the developed world have CVI and around 10% of all children with developmental disorders are affected [Swaminathan, 2011]. CVI is also associated with premature birth, cerebral palsy and a range of other conditions. In many cases, impaired visual function is difficult to detect and often goes unnoticed unless the visual loss is very severe. As a result, CVI remains the top priority in the area of childhood-onset eye disorders set by the Sight Loss and Vision Priority Setting Partnership [Rowe et al., 2014] and the James Lind Alliance [see references]. Because the pattern of visual loss in each child is often unique, but the assessment tools are general, a novel approach is needed.
Recent work from our lab, funded by Fight for Sight, has established a new set of precision imaging tools that allows us to combine information from cortical loss maps (measured with fMRI), visual field coverage (with perimetry), as well as anatomical markers of gray and white matter damage [Beh et al., 2021]. These measures will allow us to better quantify residual function in the visual brain and help guide rehabilitative strategies in individuals with CVI.
-- Importance / impact --
This project will enable us to develop a new line of research (applying our methodology to a large potential cohort of patients). This will strengthen connections to the medical school in collaboration with Prof R Dineen (Academic Radiology), Mr S Thomas (Ophthalmology) and others at QMC. Our team has also secured funding for scan time at the SPMIC, which will allow a successful applicant to scan a pilot cohort (10 participants). These pilot data will form the basis of funding applications to the Wellcome Trust and the MRC.
-- References --
Beh A, McGraw PV, Webb BS, Schluppeck D, 2022. Front. Neurosci. https://www.frontiersin.org/articles/10.3389/fnins.2021.737215/full
Chang, M.Y. and Borchert, M.S., (2020(. Survey of ophthalmology, 65(6), pp.708-724.
James Lind Alliance – https://www.jla.nihr.ac.uk/priority-setting-partnerships/sight-loss-and-vision/top-10-priorities/childhood-onset-disorders-top-10.htm
Papanikolaou, A., Keliris, G. A., Papageorgiou, T. D., Shao, Y., Krapp, E., Papageorgiou, E., et al. (2014). Proc. Natl. Acad. Sci. U.S.A. 111, E1656–E1665. doi: 10.1073/pnas.1317074111
Rowe, F., Wormald, R., Cable, R., Acton, M., Bonstein, K., Bowen, M., Bronze, C., Bunce, C., Conroy, D., Cowan, K. and Evans, K., 2014. BMJ open, 4(7), p.e004905.
Swaminathan M. (2011). Cortical visual impairment in children - A new challenge for the future?. Oman journal of ophthalmology, 4(1), 1–2. https://doi.org/10.4103/0974-620X.77654