Multiple Object Tracking While Walking: Similarities and Differences Between Young, Young-Old, and Old-Old Adults Kristell Pothier,1,2,3,4 Nicolas Benguigui,2,5 Richard Kulpa,6 and Chantal Chavoix1,2,3

Objective. Walking while simultaneously engaged in another activity becomes more difficult as one grows older. Here, we address the issue of changes in dual-task behavior at different stages of life, particularly in the latter stages. Methods. We developed a dual task that combined walking along an 8-m walkway with a multiple object tracking (MOT) task of increasing difficulty. This secondary cognitive task imitates visuospatial daily activities and provides reliable quantitative measurements. Our dual-task paradigm was tested on 27 young adults (23.85 ± 2.09 years old) and two groups of older adults (18 young-old and 18 old-old adults, aged 63.89 ± 3.32 and 80.83 ± 3.84 years, respectively). Results. Significant decrease in tracking performance with increasing complexity of the MOT task was found in all three groups. An age-related decrease in MOT and gait performance was also found. However, young-old adults performed as well as young adults under low attentional load conditions (in the MOT task and simple walking), whereas their performance was as impaired as those of old-old adults under high attentional load conditions (in the MOT task and walking under dual-task condition). Discussion. These different profiles between the two groups of older participants could be explained in terms of compensation strategies and risk of falling.