Effects of Dual-Tasks on Spatial-Temporal Parameters of Gait in Older Adults with Impaired Balance

Abstract

Objectives Studies have shown that doing dual tasks during walking could radically change the pattern of walking\reven in healthy older people. The study of spatial-temporal parameters and their changes in walking with\rdual tasks, symmetry in right and left legs functions as well as changes in these parameters have received\rscant attention from researchers. Therefore, the purpose of this study was to evaluate the changes in spatialtemporal\rparameters of walking due to their simultaneous execution with cognitive dual-task in older people\rwith impaired balance.\rMethods & Materials Thirty older adults with weak balance voluntarily participated in this study. The study\rsubjects were selected through Berg and Mini-Mental State Examination (MMSE) tests. The subjects who got\rscores lower than 52 in the Berg test were allowed to participate in the study. On the other hand, those who\rgot scores lower than 23 in the MMSE test were excluded from the study. After subjects’ familiarity with the\rmeasurements and taking their informed consents, they walked 12 meters under 2 conditions; normal walking\rand walking with a cognitive dual-task. Spatial-temporal kinematic parameters were recorded by Vicon\rcameras. Then, by using the Polygon software, the variables of cadence, walking speed, step length, stride\rlength, duration of step and stride, duration of stance and swing, time of single leg support and double leg\rsupport, separation of other leg, touching of other leg to the ground, and time of separation of fingers were\rcalculated in terms of percentages of walking cycle. The obtained data were analyzed using repeated measures\rANOVA at a significant level of P<0.05.\rResults The results showed that among the examined parameters, the variables of cadence and walking speed\rduring walking with dual-task were reduced significantly compared to normal walking. The duration of the\rstep, stride, time of double support, time of single leg support, the time of standing and swing in walking\ralong with dual-task compared to normal walking showed a significant reduction (P<0.05). Asymmetry index\rin walking with dual-task compared to normal walking showed a significant increase in parameters of\rcadence, duration of step and stride; however, the changes in other parameters were not significant. The\rfindings showed that the changes in stepping parameters from one step to the next one in walking with dualtask\rcompared to normal walking had no significant changes. In other words, the older people with impaired\rbalance had similar steps. Moreover, despite a significant decrease in speed and stance and swing time, the\rtiming of the 2 phases of stance and swing with and without dual-task did not show any significant differences.\rConclusion The results showed that the duration of double reliance and stance increase when walking with\rdual task than when normal walking. Therefore, in the elderly with poor balance, doing dual-task with walking\rcould increase the risk of fall. With regard to increase in asymmetry in walking with dual-task, it seems that\rmutual harmony and symmetry is very sensitive to concurrent cognitive task. This asymmetry in the function\rof legs is considered a risk factor in falling. Thus, based on the results, walking of the elderly with poor balance\rneeds better cognitive performance. Doing concurrent cognitive tasks could intervene with attention sources\rand consequently change the walking pattern. Therefore, we recommend that the older people with weak\rbalance and prone to falling should refrain from cognitive dual-task during walking and focus on walking itself.