The influence of dual-tasking on postural control in young adults

The aim of this study was to investigate the influence of dual-tasking on postural balance in young adults. Participants were 20 college students (10 men and 10 women) with a mean age of 25 years. Postural balance was evaluated by the Sensory Organization Test (SOT), using the Smart Equitest(tm) NeuroCom(r) International, which evaluates the individual's ability to use the different systems of postural control (somatosensory, vestibular and visual) to keep in balance in the 6 conditions of sensory conflict presented by the system. The subjects were evaluated while single-tasking (maintaining balance) and dual-tasking (maintaining balance in conjunction with cognitive mental calculation task) in randomized order. Balance was measured by using the balance score, comparing the angular differences between the maximum anterior and posterior displacements. The Wilcoxon test with significance level of p(0.05 was used to compare the mean scores of balance between the situation with and without dual task. The balance scores in SOT conditions were analyzed and demonstrated statistically significant differences in condition 1 (eyes open, fixed platform and visual surroundings; p=0.018) and condition 6 (eyes open, platform swings and fixed visual surroundings; p=0.008), with reduced balance when dual-tasking in both conditions. The results showed that while performing dual tasks, consisted of four arithmetic operations, the posture control is negatively affected, resulting in a greater oscillation of the subjects. Thus, the complexity of the secondary task may have been the main reason for the lower balance scores found.

本研究旨在探讨双任务对青年成年人姿势平衡的影响。本研究共纳入20名大学生受试者（男10名、女10名），平均年龄25岁。姿势平衡采用智能平衡测试系统（Smart Equitest™ NeuroCom® International）开展感觉组织测试（Sensory Organization Test, SOT）进行评估；该系统可针对系统呈现的6种感觉冲突场景，评估个体利用不同姿势控制系统（躯体感觉、前庭及视觉系统）维持平衡的能力。受试者按随机顺序分别在单任务（仅维持身体平衡）与双任务（维持平衡同时完成认知心算任务）条件下接受评估。平衡表现通过平衡分数进行量化，以身体前后最大位移的角度差值作为量化指标。本研究采用显著性水平为p<0.05的Wilcoxon检验，比较双任务与单任务条件下的平均平衡分数。对SOT各测试条件下的平衡分数进行分析后发现，条件1（睁眼、平台固定且视觉环境固定；p=0.018）与条件6（睁眼、平台摆动且视觉环境固定；p=0.008）存在统计学显著性差异，且双任务条件下这两种场景的平衡能力均出现下降。结果表明，在执行包含四则运算的双任务时，受试者的姿势控制会受到负面影响，导致身体摆动幅度增大。由此可见，次级任务的复杂度可能是本研究中平衡分数降低的主要原因。