A simple interception task used as diagnostic tool of multisensory integration problems in aging

To live independently, older adults (OA) need to properly integrate sensory information from their environment to perform the activities of daily living (ADL). If a reliable relation between MSI and the performance of ADL can be shown, a measure of MSI may be used as an early diagnostic/predictive tool for ADL problems in individual OA. This thesis aims to develop this tool to allow clinicians developing personalized interventions to help OA maintain their quality of life and stay independent. We showed that aging influences sensory integration. We used an interception task with disappearing targets moving downwards on a screen while the background was moving horizontally creating an illusion of motion of the target. We added dual tasks to the baseline perturbing the proprioceptive and vestibular inputs or increasing the cognitive load. Overall, OA without any problem to perform ADL tend to have a larger effect of the illusion as compared to YA. However, OA with a range of ADL difficulties showed three different patterns of illusion effect: a (large) illusion effect (‘over integration’ pattern), a reverse illusion effect (‘dragged by the background’ pattern) and no illusion effect (‘minimal use of visual information’ pattern). We developed a transitional model of the aging process happening in our task. Our task alone can predict the results of ADL-related clinical pretests measuring issues in sensorimotor systems that contribute to postural control, ADL issues, functional change of transitional movements, survival rates and life expectancy. This thesis was a first step towards the development of a clinical tool that could assist the diagnosis of MSI issues in OA and predict the onset of problems in ADL.