Effect of Dual Task Paradigm on Standing Postural Stability under Static and Continuous Support Surface Translational Perturbation Conditions

Previous studies have found that dual-task paradigm promotes a more automated approach to postural control. A more demanding secondary cognitive task in a dual-task paradigm can result in better stability than a less cognitively demanding task. This study intends to investigate the effect of the dual-task paradigm on postural stability when the difficulty of the primary postural task in dual-task paradigm is varied. 18 participants (14 Male,4 Female; 22.5 ±1.8 years) were recruited. Postural task in 4 difficulty levels consists of static conditions: Feet Together (FT) and Tandem Stance (TS), and continuous support surface perturbation conditions: Feet Together Translational Perturbation (FTTP) and Tandem Stance Translational Perturbation (TSTP). Cognitive tasks with 2 difficulty levels consist of the easier discrete cognitive task: The go/no go task, and the more difficult continuous cognitive task: the number sequence task. Results show a significant difference between cognitive task and sway area for FT, TS,& FTTP postural tasks during dual-task conditions (p<0.05). FT & TS show reduced sway variability in the Anterior-Posterior (AP) direction(p<0.05), while only TS shows reduced sway variability in the Medial-Lateral (ML) direction (p<0.05). TS also shows slower velocity in the AP and ML directions. Postural stability improvement was more pronounced during the more difficult continuous cognitive task. The most difficult postural task, TSTP did not show a significant difference between the parameters and the cognitive task (p>0.05). We concluded that the difficulty of the cognitive task used in this study was unable to draw attention away from TSTP to achieve a more automatized approach to postural control. TS shows the most pronounced improvement in postural stability under current cognitive task difficulty. A protocol to personalize the difficulty of postural and cognitive tasks to each individual and reconsider parameters is suggested for similar future studies.