title: Aging affects postural tracking of complex visual motion cues.
abstract: Postural tracking of visual motion cues improves perception-action coupling in aging, yet the nature of the visual cues to be tracked is critical for the efficacy of such a paradigm. We investigated how well healthy older (72.45 ± 4.72 years) and young (22.98 ± 2.9 years) adults can follow with their gaze and posture horizontally moving visual target cues of different degree of complexity. Participants tracked continuously for 120 s the motion of a visual target (dot) that oscillated in three different patterns: a simple periodic (simulated by a sine), a more complex (simulated by the Lorenz attractor that is deterministic displaying mathematical chaos) and an ultra-complex random (simulated by surrogating the Lorenz attractor) pattern. The degree of coupling between performance (posture and gaze) and the target motion was quantified in the spectral coherence, gain, phase and cross-approximate entropy (cross-ApEn) between signals. Sway-target coherence decreased as a function of target complexity and was lower for the older compared to the young participants when tracking the chaotic target. On the other hand, gaze-target coherence was not affected by either target complexity or age. Yet, a lower cross-ApEn value when tracking the chaotic stimulus motion revealed a more synchronous gaze-target relationship for both age groups. Results suggest limitations in online visuo-motor processing of complex motion cues and a less efficient exploitation of the body sway dynamics with age. Complex visual motion cues may provide a suitable training stimulus to improve visuo-motor integration and restore sway variability in older adults.
authors.affiliation: Motor Control and Learning Laboratory, Department of Physical Education and Sport Science, Aristotle University of Thessaloniki, 546 24, Thessaloniki, Greece.
authors.forename: H
authors.initials: H
authors.lastname: Sotirakis
authors.affiliation: Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kyvelidou
authors.affiliation: Department of Physical Education and Sports Science at Serres, Aristotle University of Thessaloniki, Serres, Greece.
authors.forename: L
authors.initials: L
authors.lastname: Mademli
authors.affiliation: Department of Biomechanics, University of Nebraska at Omaha, Omaha, NE, USA.|Department of Environmental, Agricultural, and Occupational Health, College of Public Health, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: N
authors.initials: N
authors.lastname: Stergiou
authors.affiliation: Motor Control and Learning Laboratory, Department of Physical Education and Sport Science, Aristotle University of Thessaloniki, 546 24, Thessaloniki, Greece. vaso1@phed.auth.gr.
authors.forename: V
authors.initials: V
authors.lastname: Hatzitaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D004856:Postural Balance; D011187:Posture / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Complexity; Gaze; Posture; Visuo-motor integration