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Previous Research [to Current Studies]

For over 25 years the Visual Development Unit has been studying how visual abilities develop in infants and children, funded by the Medical Research Council first in Cambridge and now in Oxford and London. 

We have used our findings to help in assessing and understanding the problems of at-risk groups, including children who were born very prematurely and those with visual problems related to other developmental syndromes. 

We measure many different aspects of how children use vision: 

	Electrical brain responses to patterns and movements
	Judgments of shape, size and depth
	Visual attention in search and hiding tasks
	Visual memory for finding your way in new places
	Visual-motor skills such as throwing and catching a ball, balancing
	Reading and problems of dyslexia

Over the past 12 years, with the help of the WS Foundation, we have carried out detailed studies of development in children with Williams Syndrome using many different tests over the whole age range from newborn to adulthood. We have seen more than 160 individuals from the Williams Foundation, some of them several times. 

People with Williams Syndrome find visuo-spatial tasks particularly difficult. However, our studies have shown an uneven profile within the visuo-spatial domain. We find that many WS individuals have common childhood visual problems such as long and short sightedness and strabismus (cross eyes). But while some visuo-spatial tasks are indeed very difficult for WS individuals (for example copying block constructions and making fine coordinated motor movements) others are less so and can improve remarkably with special strategies and practice. 

Our findings on individuals with WS are an important first step towards devising ways in which they can improve their daily lives by capitalising on their strengths while working around the areas of weakness. Because we are a research group, our findings are published in scientific journals. Some of these are listed below but we can send you the complete list on request. 

We hope, through our work, to help members of the Foundation both in educational terms and in everyday life. We will be happy to talk to you about our studies and about the results of any measures made on any WS individuals. Although of course nobody knows all the answers to the many questions about WS, we are always happy to talk to WS adults and to parents to give any help we can.
 

Neurobiological Model of Visual Information Processing in Williams Syndrome 

In the human brain, separate pathways are used to recognise objects, including the recognition of faces (ventral stream), and to register where they are and how to act on them (dorsal stream). In Williams Syndrome, we have identified particular difficulties with certain tasks that depend on the dorsal but not the ventral stream [1, 2]. In everyday life these may be difficulties with certain visuomotor skills such as writing, drawing, catching a ball, walking on uneven surfaces, crossing roads in traffic. 

We have devised special tests to measure how well the dorsal and ventral streams within the brain are operating. We find that children with Williams Syndrome are generally much better at matching the orientation of a letter to a post box slot (perceptual judgment; ventral stream), than actually posting the letter (action task; dorsal stream). Likewise, many WS individuals detect shapes and forms (ventral stream) better than motion (dorsal stream) against a noisy background. 

We have also found that children in Williams Syndrome have difficulties on tasks in which they have to inhibit a familiar response, which depend on a particular brain area, the prefrontal cortex [2, 3]. However their profile on the inhibition tasks is also uneven, with performance on those that involve verbal responses better than on spatially directed motor responses [2], and WS individuals may be able to successfully reduce the frontal impairment by assisting themselves with verbal strategies. 

We have collaborated with the Hammersmith Hospital on a brain imaging study [5], in which we found unusual brain changes in WS infants aged under 3 years, which may be associated with the behavioural differences we have described. Our current newer studies assessing attention (frontal lobe), spatial memory (parietal lobe), and visually guided movement (dorsal visual stream and motor cortex) is providing us with increasingly detailed insights into the neurobiological characteristics of Williams Syndrome and the wide variety of abilities and problems from one individual to another. 

We have just sent out a short questionnaire about the many fascinations and hobbies of WS individuals. We have had so many interesting replies (for example fascinations with washing machines, frogs, ear-rings, rubber gloves) we could write a book about them! It makes us realize what unique brains and thoughts WS individuals possess. 
 

Visual Assessment 

We have also carried out detailed assessments of more basic visual functions, including acuity and stereopsis, in Williams Syndrome. 

Our studies have confirmed that WS individuals have a very high incidence of visual problems including strabismus (squint - 'cross eyes'), poor stereo (3D) vision, and poor focusing [6, 7]. However we find no evidence for a direct association between these visual problems and performance on visuo-spatial tasks such as block construction copying [7]. 

Although poor vision in Williams Syndrome is of concern to us, we are able to rule out the possibility that it is responsible for the pattern of the many visuo-spatial problems we have found - the evidence rather points to a more complicated neurological basis in the brain.
 

Current Studies [to Previous Research]

1. Navigation and Spatial Memory 

Individuals with Williams Syndrome are often said to have difficulties finding their way around, but the nature of these spatial problems has been poorly understood. Our current studies aim to separate the different components of spatial memory to see which may be particularly impaired in Williams Syndrome. In particular there are different processes for remembering where objects are -

	In relation to the body
	In relation to landmarks in the surroundings.

We have adapted a virtual reality test for memory of locations from new viewpoints [8]. We found WS children and adults generally do well when there was only one place to remember and when the viewpoint did not change. However from a changed viewpoint WS individuals find the task much more difficult, with a specific difficulty in remembering where objects are in relation to landmarks [9]. From the same viewpoint performance also fell when there was a second object. 

In our second task testing memory for location of hidden objects [10], the participant physically moved from one location to another. WS individuals were now able to recall places from a new viewpoint provided that they made the movement themselves. Although, overall, they were less accurate at spatial localisation than were control groups, they were relatively good at remembering where objects were in relation to the body. Some individuals could achieve better performance with the strategy of using words to remember places. 

So far we can conclude that individuals with WS are not equally impaired on all aspects of navigation and spatial memory, and that their least good functions may be improved with conscious use of verbal strategies. Our current studies are following up these initial findings in more detail.

Contact: Marko Nardini / m.nardini [AT] ucl.ac.uk

2. Attention 

Attention is the ability to control how we allocate the brain's processing resources, in a manner appropriate to our current goals. It is essential to successful functioning in many areas of life. At least some aspects of attention are areas of difficulty for people with Williams Syndrome [3, 4]. 

We have used the established 'Test of Everyday Attention for Children' (TEA-Ch) [11] in the assessment of children's attention. However, this test not suitable for children under 6 years old, and may also not give a proper measure of the abilities of people with learning difficulties such as WS. One of our current projects is developing new measures of attention that are appropriate for these groups. 

Both the TEA-Ch and these new measures aim to measure distinct aspects of attention, which are separable in children and adults and may reveal distinctive patterns of difficulty for Williams Syndrome individuals: 

Selective attention - the ability to focus on relevant aspects of a stimulus or task, whilst ignoring distraction from irrelevant information.

Sustained attention - the ability to maintain a focus on the current task, even in situations of little intrinsic interest or motivation.

Control of attention - including, for example, the ability to switch attention between different tasks, or inhibit actions that are well-learned or automatic but inappropriate with respect to the current goals.

 
Selective attention task: "find all the complete cats and dogs"

Identifying the strengths and weaknesses in WS individuals should help in guiding them to the best strategies for coping with the attention demands of school and everyday life. 

Contact: Kate Breckenridge / k.breckenridge [AT] ucl.ac.uk

3. Vision and Stair Descent 

Many WS individuals find particular difficulties in walking over uneven surfaces [12], and in particular walking down stairs. These tasks require them to use visual information, in a rapid and automatic way, to guide their actions. In a new project, we aim to look at how typically developing children come to use visual information to guide their stair descent, and how this may differ in WS. If we can understand the basis of their difficulties, this may help in guiding WS individuals to develop strategies that allow them safer and easier descent. 

There is quite detailed data on adult stair descent [13], but we know much less about how this develops in children. We will observe children's stair descent on stairs of different heights, under a variety of visual conditions. In some cases, we will measure the detailed pattern of movement using a complex system of cameras that feed data into a computer. 

We will be studying both typical and WS development. Questions we will study include-
do children and WS individuals: 

	Show appropriate 'body-scaling' (i.e. become more unwilling to attempt descent on very steep stairs)?
	Modify step length appropriately when approaching and descending steps?
	Raise their feet above the ground more on the first few stairs, as adults do?
	Depend particularly on the peripheral visual field for guiding stair descent? If so, it might aid safety and confidence to provide markings or lights on the banisters.

Contact: Dorothy Cowie / dorothy.cowie [At] psy.ox.ac.uk

References 

[1] J Atkinson, J King, O Braddick, L Nokes, S Anker, F Braddick. "A specific deficit of dorsal stream function in Williams' syndrome". Neuroreport 8, 1919-1922 (1997) 

[2] J Atkinson, O Braddick, S Anker, W Curran, R Andrew, J Wattam-Bell, F Braddick. "Neurobiological models of visuo-spatial cognition in young Williams Syndrome children: Measures of dorsal-stream and frontal function". Developmental Neuropsychology 23(1/2): 139-172 

[3] J Atkinson, F Braddick, L Nokes, " Frontal control processes in Williams syndrome children". Perception 26 (6) 763 (1997) 

[4] J Atkinson, O Braddick, S Anker, W Curran, R Andrew, F Braddick. "Neurobiological models of visuo-spatial cognition in young Williams Syndrome children: Measures of dorsal-stream and frontal function". Developmental Neuropsychology 23(1/2): 141-174 

[5] E Mercuri, J Atkinson, O Braddick, M Rutherford, F Cowan, S Counsell, L Dubowitz, G Bydder. "Chiari I malformation and white matter changes in asymptomatic young children with Williams syndrome: clinical and MRI study".European Journal of Paediatric Neurology 5/6 177-181 (1997) 

[6] O Braddick, J Atkinson, S Anker, F Macpherson, L Nokes, S Rae, D Ehrlich. "Visual and visuo-spatial development in young children with Williams Syndrome". Strabismus 3 (4): 179 (1995) 

[7] J Atkinson, S Anker, O Braddick, L Nokes, A Mason, F Braddick. "Visual and visuo-spatial development in young Williams Syndrome children". Developmental Medicine and Child Neurology, 43: 330-337 (2001) 

[8] J King, N Burgess, T Hartley, F Vargha-Khadem, & J O'Keefe (2002). Human Hippocampus and Viewpoint Dependence in Spatial Memory. Hippocampus, 12, 811-820. 

[9] J Atkinson, O Braddick, S Anker, M Nardini, U Bellugi, F E Rose, Y Searcy, N Bavar "Extending the 'dorsal stream vulnerability hypothesis': spatial reorientation and motion and form coherence in children and adults with Williams syndrome". Poster presentation, Vision Sciences Society 2003 

[10] M Nardini, K Breckenridge, R Eastwood, J Atkinson, O J Braddick. "Distinct developmental trajectories in three systems for spatial encoding between ages 3 and 6 years". Perception S33: 28 

[11] T Manly, I Nimmo-Smith, P Watson, V Anderson, A Turner, & I H Roberston (2001). "The differential assessment of children's attention: the Test of Everyday Attention for Children (TEA-Ch), normative sample and ADHD performance." Journal of Child Psychology and Psychiatry, 42(8), 1065-1081. 

[12] S Withers (1996) A new clinical sign in Williams Syndome. Archives of Disease in Childhood, 75, 89. [13] P R Cavanagh, & J S Higginson (2003) "What is the role of vision during stair descent?" In A.Jeffrey, D. Owens, (Eds) Visual Perception: the influence of H. Leibowitz, Decade of behaviour. (pp 213-230). Washington DC, US: American Psychological Association. xix, 253.

Visual Development Unit, Division of Psychology and Language Sciences
University College London, Gower Street London WC1E 6BT UK
Telephone: +44 (0)20 7679 7574 Fax +44 (0)20 7679 7576
Email: vdu [AT] psychol.ucl.ac.uk

Updated June 2010