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Project title
Subtyping of childhood cerebral visual impairment: what are the visual perceptual and neurophysiological underpinnings?
Supervisors names
Professor Naomi Dale
Associate Professor Mr Richard Bowman
Background
Cerebral visual impairment (CVI) is the most common cause of visual impairment in higher income countries, with growing prevalence. It involves dysfunction of the posterior visual pathways, visual cortex and associated areas, including visual perception affecting acuity, field and depth vision, object/picture recognition, spatial and motion perception and neuro-ophthalmological characteristics1. Our team has recently established that there are two data-driven ‘clusters’ or subtypes of higher functioning CVI using a standard assessment method of basic vision and visuo-neuropsychological tests2. Very little is known about the visual perceptual, functional and neurophysiological underpinnings of the two subtypes though one group appears ‘dorsal’ (affecting visuo-spatial perception and visuo-motor integration and possibly 3-D vision) and the other broad ‘visual perceptual/ventral’ (affecting motor-free visual perceptual tests and possibly 2-D vision).3, 4 This is of high diagnostic relevance to clinicians and vision neuroscientists for understanding more about the brain visual system, its underlying neurophysiology and the related clinical disabilities. This will lead to better diagnostics, habilitation and management of care in the future.
Aims/Objectives
This study sets out to examine whether
1. children within higher functioning CVI fall into two data-driven subtypes that appear to be dorsal and broad visual perceptual/ventral according to vision neuropsychological test results and the literature,
2. vision paradigms designed to elicit dorsal or ventral/ visual perceptual patterns show differences in activation of localised brain areas between the two clusters. Attainment abilities, including mathematics, will also be associated with subtype as predicted.5
Methods
The PhD student will undertake a systematic review to design suitable paradigms for eye tracking/fMRI analysis. A scientific investigation will be performed with school-aged children with diagnosed or suspected CVI in the higher functioning range and typically healthy controls. The student will be trained to administer the assessment methods, followed by establishing their subtype. Vision function tests of ‘dorsal’ and broad ‘visual perceptual/ ventral’ are studied whilst eye tracking/fMRI brain scanning. Attainment tests, with focus on mathematics, will be undertaken and associations explored.
Training in eye tracking/ fMRI methods will be supervised by Professor Michelle De Haan and Associate Professor Tessa Dekker (Child Vision Laboratory UCL). A neurodisability paediatrician (Developmental Vision Clinic) will participate as consultant.
Timeline
The project will be undertaken at UCL GOS Institute of Child Health in the Developmental Neurosciences department, working closely with the Child Vision Lab UCL.
- First year: to undertake the systematic review, design test paradigms and receive training for assessment testing and eye tracking/fMRI. The student will help obtain Ethics approval and commence recruitment.
- Second year: to undertake recruitment and assessment testing and eye tracking/ fMRI testing with subject sample and control group.
- Third year: to complete final assessment testing, data extraction and statistical analyses and writing of dissertation.
References
1 Cerebral Visual Impairment. In Dale N et al 2022 Childhood vision impairment. MacKeith Practice Guide
2 Sakki H, et al 2021 Dev Med Child Neurology, 63(3), 303-312.
3 Atkinson J, Braddick O. Prog Brain Res. 2011;189:261-83.
4 Sakki H, et al 2022 Front Hum Neurosci. 2022 Jan 6;15:765371.
5 Hawes Z, et al 2019. Neuroscience and Biobehavioral Reviews. 103, 316.336.
Contact
Naomi Dale n.dale@ucl.ac.uk