Effects of saccadic eye movements on postural control in older adults.

Abstract

Saccadic eye movements have been shown to affect posture by decreasing the magnitude of body sway in young adults. However, there is no evidence of how the search for visual information that occurs during eye movements affects postural control in older adults. The purpose of the present study was to determine the influence of saccadic eye movements on postural control in older adults while they stood on 2 different bases of support. Twelve older adults stood upright in 70-s trials under 2 stance conditions (wide and narrow) and 3 gaze conditions (fixation, saccadic eye movements at 0.5 Hz, and saccadic eye movements at 1.1 Hz). Head and trunk sway amplitude and mean sway frequency were measured in both the anterior/posterior (AP) and medial/lateral (ML) directions. The results showed that the amplitude of body sway was reduced during saccades compared with fixation, as previously observed in young adults. However, older adults exhibited similar sway amplitude and frequency in the AP direction under the wide and narrow stance conditions, which is different from observations in young adults, who display larger sway in a narrow stance compared with a wide stance while performing saccades. These results suggest that although older adults are affected by saccadic eye movements by a decrease in the amplitude of body sway, as observed in young adults, they present a more rigid postural control strategy that does not allow larger sway during a more challenging stance condition.Keywords: aging, eye movements, posture, saccades, visual information Postural control is fundamental for performing numerous daily activities. The main behavioral goals involved in the control of posture are postural equilibrium (related to the balance of forces that act on the body) and postural orientation (related to the positioning of body seg-

Saccadic Eye Movement Improves Plantar Sensation and Postural Balance in Elderly Women

“…Stoffregen et al (2006) found that head and trunk sway changes while performing saccades and visual fixation with the eyes closed and open. In particular, body sway is more reduced during SEM than gaze fixation, and the amplitude of postural sway is reduced in both young adults and the elderly during SEM (Aguiar et al 2015). These findings suggest that elderly individuals depend on vision to control postural balance.…”

“…In total, 104 elderly participants who could walk unaided were screened. In previous studies (Aguiar et al 2015;Rodrigues et al 2015), the subjects were young adults and elderly individuals, but the sex was not disclosed. More than 80% of the subjects who wished to participate in this study were women.…”

“…4) The eye was then closed for 30 seconds. The target's moving frequency was set at 0.5 Hz based on Aguiar et al (2015).…”

“…Considering the findings of previous studies (Stoffregen et al 2006;Aguiar et al 2015;Rodrigues et al 2015), the aim of the present study was to evaluate the improvement in postural balance and the plantar surface area (PSA) of the feet in contact with the floor surface when SEM and PEM were performed in community dwelling older adults who maintained postural balance with their eyes open and closed. The following was our research hypothesis: SEM and PEM will both improve information provided by plantar sensation (PS) and postural balance, but SEM will improve postural balance to a greater extent.…”

What information is being acquired during the period of Quiet Eye? Comment on Vickers

“…For instance, the Gibsonian notion of visual system ("eyes-in-the-head-on-the-bodyresting-on-the-ground"; Gibson, 1979, p. 205) favors the simultaneous consideration of gaze and postural data during motor actions. Continuous and predictable saccadic and smooth pursuit eye movements improve postural stabilization during quiet stance (Aguiar et al, 2015;Rodrigues et al, 2013;Rodrigues et al, 2015); in more dynamical contexts, increased postural stability due to motor learning has been reported in a variety of motor skills, such as rifle shooting (Era, Konttinen, Mehto, Saarela, & Lyytinen, 1996) and manual rhythmic movements (Amado, Palmer, Hamill, & van Emmerik, 2016). Interestingly, expertise of ball cascade jugglers seems associated with parsimonious oculomotor and attention pattern ("gaze-through" strategy) with fixations at the scene's central location, weaker frequency locking between point-of-gaze and ball movements, reduced dependency to visually tracking ball motion, and improved anterior-posterior body sway stabilization (Dessing, Rey, & Beek, 2012;Huys & Beek, 2002;Huys, Daffertshofer, & Beek, 2004;Rodrigues et al, 2016), which is in line with experts' higher capability of decoupling postural control and arm movements (Amado et al, 2016).…”