Higher visual dependency increases balance control perturbation during cognitive task fulfilment in elderly people

Ageing results in a decrease in balance control and correlatively raises the risk of falling. Furthermore, dual task situations can increase this age-related imbalance. Within this context, this study aimed to determine the differentiated effects of carrying out cognitive tasks on balance control in 40 healthy older adults. The visuo-verbal Stroop task did not affect postural regulation precision whereas a mental counting task provoked higher instability. Moreover, the results showed a correlation between the degree of visual dependency and postural perturbation. Executing a mental counting task can cause reorientation of visual attention from external landmarks to internal visual images of the calculation. As elderly subjects are more dependent on visual information to ensure balance control, this loss of external visual anchorage when executing a mental task therefore explains the balance perturbation observed.