Methodological and interpretive issues in posture-cognition dual-tasking in upright stance

The traditionally separate researches on cognitive functions and basic coordinations such as stance and locomotion are coming together in the study of posture-cognition dual-tasking. The importance of this growing research area lies not only in the ubiquitous coexistence of postural and cognitive tasks but also in the observation that posture control very often has the dual role of securing the body's safety and balance while also providing a versatile, stable physical substrate well-suited to perception-action tasks. Although dual-task investigations strongly suggest that posture control and higher level cognition have common resource requirements, inconsistencies in the data and differences in experimental design make it difficult to distill a fuller understanding of the specific mechanisms behind posture-cognition dual-tasking. In this paper, we review the literature on upright standing with concurrent cognitive tasks, and highlight paradigmatic variations that possibly contribute to dual-task data differences. Implications arising from theoretical assumptions made about the role of postural control in the concurrent performance of cognitive tasks are also discussed. (c) 2007 Elsevier B.V. All rights reserved.