Assessing cognitive functioning in females with Rett syndrome by eye-tracking methodology

Background While many individuals with severe developmental impairments learn to communicate with augmentative and alternative communication (AAC) devices, a significant number of individuals show major difficulties in the effective use of AAC. Recent technological innovations, i.e., eye-tracking technology (ETT), aim to improve the transparency of communication and may also enable a more valid cognitive assessment. Objectives To investigate whether ETT in forced-choice tasks can enable children with very severe motor and speech impairments to respond consistently, allowing a more reliable evaluation of their language comprehension. Methods Participants were 17 girls with Rett syndrome (M = 6:06 years). Their ability to respond by eye gaze was first practiced with computer games using ETT. Afterwards, their receptive vocabulary was assessed using the Peabody Picture Vocabulary Test-4 (PPVT-4). Target words were orally presented and participants responded by focusing their eyes on the preferred picture. Results Remarkable differences between the participants in receptive vocabulary were demonstrated using ETT. The verbal comprehension abilities of 32% of the participants ranged from low-average to mild cognitive impairment, and the other 68% of the participants showed moderate to severe impairment. Young age at the time of assessment was positively correlated with higher receptive vocabulary. Conclusions The use of ETT seems to make the communicational signals of children with severe motor and communication impairments more easily understood. Early practice of ETT may improve the quality of communication and enable more reliable conclusions in learning and assessment sessions.