The role of vision in the postural control of children

For adults, the role of saccadic information in the control of postural sway is well established. In children, the role of normal vision is less well understood. Two studies investigated how children aged 5-7, 8-9, and 10-12 years and adults use visual information in the control of postural sway. In Study 1, Romberg quotients (RQ) were used to determine the relative influence of vision in postural control. Subjects stood on a force plate in either a normal or Romberg (heel to toe) stance and with eyes open or closed. Throughout each experiment, eye movements were monitored using the corneal reflection technique. Data for eye movements and centre of pressure changes for lateral (LAT) and antero-posterior (A-P) sway were analyzed. Both LAT and A-P sway and number of eye movements decrease with age, and are less in the normal vs. Romberg stance. The only groups who find vision stabilizing (high RQ) are older children (10-12) and adults. Study 2 examined the effects of LAT and A-P sway of visually tracking lights alternating at high (2.0 Hz), medium (1.0 Hz) or low (0.5 Hz) frequencies. Analyses of eye movements indicated that young children make more eye movements; however, the quality of information provided by the movements is less than in older children or adults. While postural stability improves with age, a heel-to-toe stance remains more difficult than normal standing.