Age-related features of walking with cognitive tasks

Human walking is considered as a complex cognitive act. The research purpose is an analysis of age-related features of spatio-temporal parameters of human walking and directions of their changes at walking with dual (cognitive) tasks. The walking spatio-temporal indexes were studied in 608 individuals of both sexes aged 12-43 years by GAITRite® (CIR Systems Inc.,Clifton, NJ) under normal walking at individually comfortable velocity and under additional cognitive tasks: 1) sequentially pronounce aloud any known animals; 2) starting from a number 100, subtract 7 and pronounce the result aloud. The statistical processing of the got results was carried out in the licensed software “STATISTICA 5.5”. At performing the first, simpler, task, the spatial parameters had no significant changes in all age groups. Most of the temporal parameters changed: cycle time, swing time, single support time, and double support time increased. Therefore, equilibrium maintaining at walking with naming animals is realized with a longer overall support period, reducing the walking cadence and velocity. The constant width of the support base and the angle of the feet turn indicate that the magnitudes of the functional support base and angle of the feet turn at normal walking is sufficient to maintain posture and balance at walking with simultaneous performance of the cognitive task, as well as more rigid mechanisms of regulation of these two parameters. The walking temporal parameters are more labile than spatial parameters. With age, the percentage of the integral index of walking quality (FAP) decreases especially in females: in girls by 15.3 %, in young women by 14.4 %, in middle-aged women by 7.4 %. At performing the second, more complex, arithmetic task, in young men and young girls support base, toe-in-out, step length difference had no significant changes only. The mean velocity, cadence, step length, stride length, step extremity ratio decreased. The count of steps, all temporal parameters, and stance percentage increased. FAP declined critically by 30.4 % in young men and 33.4 % in young women, indicating a decrease in balance and body stability under walking with cognitive task and increasing the risk of falls. Therefore, a significant reduction in FAP can be used as a diagnostic criterion in neurological practice.