Effects of cognitive tasks on center-of-foot pressure displacements and brain activity during single leg stance: comparison in community-dwelling healthy older and young people

[Purpose] This study aimed to investigate the effect of cognitive tasks on the center-of-foot pressure (COP) displacements and brain activity during single leg stance (SLS) in older people. [Participants and Methods] This study included 25 healthy older (age, 68.8 ± 4.9 years) and 25 young (age, 21.0 ± 0.9 years) participants. Participants performed SLS for 35 s under a single-task (ST) and three dual-tasks (DTs), namely verbal, subtraction, and recall tasks. We measured the total length of COP (COP_(TL)) and change in oxygenated hemoglobin (HbO(2)) levels during SLS under four tasks. [Results] There were no differences in COP_(TL) and HbO(2) levels in the young group, whereas COP_(TL) in the recall task was significantly longer than in ST in the older group. In the comparisons of the DTc (the relative change of DT to ST), no differences were found among three DTs in the young group, whereas the DTc of COP_(TL) in the recall task was significantly higher than that in the verbal task in the older group. Regarding HbO(2), no differences were observed among the four tasks in both groups. [Conclusion] These results suggest that SLS combined with a recall task may be useful for fall risk screening in healthy older individuals.