title: The effects of visual factors and head orientation on postural steadiness in women 55 to 70 years of age.
abstract: This study was designed to establish reference data for the effects of head position and visual conditions on the standing posture of healthy women ages 55 to 70. Center of pressure (CoP) data were analyzed using ANOVA models. Total CoP displacement was 45% greater (significant, p less than .05) when the subjects stood with their heads back and their eyes closed, as compared to standing looking straight ahead. Visual surrounds consisting of vertical visual cues resulted in less postural sway (PS) than surrounds made of horizontal visual cues (significant, p less than .05 for anteroposterior CoP range). Experimentally reduced visual acuity resulted in greater PS, while changes in ambient lighting and spatial frequency of visual cues affected PS minimally. These results suggest that a reduction in the height of shelving, and the provision of high-contrast visual cues and vertical geometric patterns are potential intervention strategies to optimize vestibular sensory input and visual orientational cues for the maintenance of stability during stance.
authors.affiliation: Center for Locomotion Studies, Pennsylvania State University, University Park 16802.
authors.forename: G G
authors.initials: GG
authors.lastname: Simoneau
authors.forename: H W
authors.initials: HW
authors.lastname: Leibowitz
authors.forename: J S
authors.initials: JS
authors.lastname: Ulbrecht
authors.forename: R A
authors.initials: RA
authors.lastname: Tyrrell
authors.forename: P R
authors.initials: PR
authors.lastname: Cavanagh
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D000843:Ankle Joint / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D006257:Head / Q000033:anatomy & histology*; D006801:Humans; D008029:Lighting; D008465:Mechanoreceptors / Q000502:physiology; D008875:Middle Aged; D009068:Movement; D010775:Photic Stimulation; D011187:Posture / Q000502:physiology*; D011312:Pressure; D011434:Proprioception / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D014110:Touch / Q000502:physiology; D014732:Vibration; D014792:Visual Acuity / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*