Multiple Object Tracking While Walking: Similarities and Differences Between Young, Young-Old, and Old-Old Adults

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. 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). 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). These different profiles between the two groups of older participants could be explained in terms of compensation strategies and risk of falling.