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Project title
Subtypes of cerebral visual impairment disorders: what are the visual perceptual and neurophysiological underpinnings
Supervisors names
Naomi Dale
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 (where the child has relatively normal acuity and no intellectual disability) using a standard assessment method of basic vision and visuo-neuropsychological tests2. Very little is known about the cognitive and vision 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, to understand more about the brain visual system, its underlying neurophysiology and related clinical disabilities. This will lead to better 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 visual perceptual/ventral according to vision neuropsychological test results and the literature,
2. vision paradigms designed to elicit dorsal or ventral/ visual perceptual patterns and localisation shows differences in activation of brain areas between the two clusters,
3. attainment abilities, including mathematics, are also differentiated by the two clusters.5
Methods
The PhD student will undertake a systematic review to design suitable paradigms for testing, eye tracking/fMRI analysis. A scientific investigation will be undertaken with a population of school-aged children with diagnosed or suspected CVI in the higher functioning range.
The student will be trained to undertake the assessment methods and analysis will be undertaken to establish their ‘cluster’ or subtype. Vision function tests of relevance for ‘dorsal’ and ‘broad visual perceptual/ ventral’ will be undertaken whilst eye tracking/fMRI is tested. In addition to primary and second supervisor (vision neuropsychology, neuro-ophthalmology), training in eye tracking/ fMRI methods by Professor Michelle De Haan and Associate Professor Tessa Dekker (head of Child Vision Laboratory UCL Department of Psychology). A neurodisability paediatrician 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, Department of Psychological Sciences UCL First year to undertake the systematic review, design the test paradigms and receive training for vision and cognitive neuropsychological assessment testing and eye tracking/fMRI. The student will help obtain health Ethics approval and commence recruitment. Second year to undertake recruitment and majority of assessment testing and eye tracking/ neurophysiological testing with all of sample and control group. Third year to complete final assessment testing, data extraction and statistical analyses and writing of the dissertation.
References
1 Cerebral Visual Impairment. In Dale N et al 2022 Childhood vision impairment: assessment, development and management. 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, Dale NJ, et Front Hum Neurosci. 2022 Jan 6;15:765371. doi
5 Hawes Z, et al 2019. Neuroscience and Biobehavioral Reviews. 103, 316.3
Contact
Naomi Dale n.dale@ucl.ac.uk