Objective measurements of gaze behaviour as a method to assess non-speaking children with severe motor impairments

Children with severe cerebral palsy (CP) affecting their whole body may experience co-occurring cognitive and language difficulties. However, access to conventional testing materials in order to determine the nature of such learning disabilities can be problematic for these children, whose motor impairments preclude the use of the functional speech and accurate pointing required as response modalities in assessment. However, careful examination of these children's eye movements in response to various stimuli may provide a way to assess effectively children's profiles of cognitive and language ability. The use of eye-tracking technology can provide ‘gold-standard’ objective and reliable measures of children's looking behaviours and in theory is well-suited to the task of assessing these children, especially those with a learning disability, when combined with assessments that do not require understanding of complex language. Questions remain, however, as to the utility of this technology to obtain data from this complex group of children. This paper will present findings from functional gaze control and preferential looking tasks involving a group of children with CP (n=66). The study demonstrated significant variability in the functional gaze control skills needed to calibrate and use eye-tracking technology to respond to preferential looking tasks. The authors will discuss the potential value of this technology in the assessment of children with CP and the clinical implications of their performance on eye-tracker based preferential looking tasks