Visual contribution to postural stability: Interaction between target fixation or tracking and static or dynamic large-field stimulus

• Published in: Gait & posture 2010-01, Vol.31 (1), p.37-41
• Main Authors: Laurens, J, Awai, L, Bockisch, C.J, Hegemann, S, van Hedel, H.J.A, Dietz, V, Straumann, D
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Body sway; Eye Movements; Female; Fixation, Ocular; Humans; Male; Middle Aged; Motion Perception - physiology; Orthopedics; Photic Stimulation; Postural Balance - physiology; Posture; Retinal flow; Vision
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2009.08.241

Abstract Stationary visual information has a stabilizing effect on posture, whereas moving visual information is destabilizing. We compared the influence of a stationary or moving fixation point to the influence of stationary or moving large-field stimulation, as well as the interaction between a fixation point and a large-field stimulus. We recorded body sway in 20 healthy subjects who were fixating a stationary or oscillating dot (vertical or horizontal motion, 1/3 Hz, ±12° amplitude, distance 96 cm). In addition, a large-field random dot pattern (extension: ∼80 × 70°) was stationary, moving or absent. Visual fixation of a stationary dot in darkness did not reduce antero-posterior (AP) sway compared to the situation in total darkness, but slightly reduced lateral sway at frequencies below 0.5 Hz. In contrast, fixating a stationary dot on a stationary large-field pattern reduced both AP and lateral body sway at all frequencies (0.1–2 Hz). Ocular tracking of the oscillating dot caused a peak in body sway at 1/3 Hz, i.e. the stimulus frequency, but there was no influence of large-field stimulus at this frequency. A stationary large-field pattern, however, reduced AP and lateral sway at frequencies between 0.1 and 2 Hz when subjects tracked a moving dot, compared to tracking in darkness. Our results demonstrate that a stationary large-field pattern has a stabilizing effect in all conditions, independent of whether the eyes are fixing on a stationary target or tracking a moving target.