Performance of Faller and Nonfaller Older Adults on a Motor-Motor Interference Task

Typically, falls in older adults occur when 2 tasks are performed simultaneously, due to the increased motor demand required to maintain stability and attention to perform the other task. The authors' purpose was to investigate walking while grasping, transporting, and placing a dowel on a predetermined target while manipulating difficulty levels of the manual task. Faller and nonfaller older adults performed a walking block (manual tasks combined with gait) and a stationary block (upright stance combined with manual tasks). The manual task involved grasping, transporting, and placing the dowel over a target. The results showed that fallers underperformed when compared with nonfallers in the task of placing the dowel over the target. The main difference observed between the groups was found in the condition that required allocation of attention between tasks and greater accuracy in the final placement of the object. Fallers showed gait stability similar to the nonfallers, but fallers were less accurate than nonfallers in the object placement task, especially for the highest level of difficulty. Thus, fallers seem to use a stability-first strategy. Fallers had problems in executing the manual tasks, which suggests a more global change in motor behavior rather than specific changes to balance control.