School of Public Health

Permanent URI for this communityhttp://hdl.handle.net/1903/1633

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.

Browse

Filters

2013 - 20152

Settings

Author: search.filters.author.Anson, Eric

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Does visual feedback during walking result in similar improvements in trunk control for young and older healthy adults?
    (Springer Nature, 2013-11-26) Anson, Eric; Rosenberg, Russell; Agada, Peter; Kiemel, Tim; Jeka, John
    Most current applications of visual feedback to improve postural control are limited to a fixed base of support and produce mixed results regarding improved postural control and transfer to functional tasks. Currently there are few options available to provide visual feedback regarding trunk motion while walking. We have developed a low cost platform to provide visual feedback of trunk motion during walking. Here we investigated whether augmented visual position feedback would reduce trunk movement variability in both young and older healthy adults. The subjects who participated were 10 young and 10 older adults. Subjects walked on a treadmill under conditions of visual position feedback and no feedback. The visual feedback consisted of anterior-posterior (AP) and medial-lateral (ML) position of the subject’s trunk during treadmill walking. Fourier transforms of the AP and ML trunk kinematics were used to calculate power spectral densities which were integrated as frequency bins “below the gait cycle” and “gait cycle and above” for analysis purposes. Visual feedback reduced movement power at very low frequencies for lumbar and neck translation but not trunk angle in both age groups. At very low frequencies of body movement, older adults had equivalent levels of movement variability with feedback as young adults without feedback. Lower variability was specific to translational (not angular) trunk movement. Visual feedback did not affect any of the measured lower extremity gait pattern characteristics of either group, suggesting that changes were not invoked by a different gait pattern. Reduced translational variability while walking on the treadmill reflects more precise control maintaining a central position on the treadmill. Such feedback may provide an important technique to augment rehabilitation to minimize body translation while walking. Individuals with poor balance during walking may benefit from this type of training to enhance path consistency during over-ground locomotion.
  • Thumbnail Image
    Item
    MECHANISMS OF GAZE STABILITY DURING WALKING: BEHAVIORAL AND PHYSIOLOGICAL MEASURES RELATING GAZE STABILITY TO OSCILLOPSIA
    (2015) Anson, Eric; Jeka, John J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Visual sensory input plays a significant role in maintaining upright posture during walking. Visual input contributes to control of head, trunk, and leg motion during walking to facilitate interaction with and avoidance of objects and individuals in the environment. The vestibular system contributes to postural control during walking and also to stabilization of the eyes during head motion which may allow for more accurate use of visual information. This dissertation reports the findings of five experiments which explore how the nervous system uses vision to control upright posture during walking and also whether the act of walking contributes to gaze stability for individuals with severe vestibular loss. In the first experiment, continuous oscillatory visual scene motion was used to probe how the use of visual input changes from standing to walking and also to determine whether the trunk motion response to visual motion was the same in the medio-lateral (ML) and anterior-posterior (AP) directions. In the second experiment, visual feedback (VFB) regarding the approximate center of mass position in the ML and AP directions was used to demonstrate that ML path stability was enhanced by concurrent visual feedback for young and older adults. In the third experiment, adults with vestibular loss and healthy adults were both able to use VFB during treadmill walking to enhance ML path stability and also to separately modify their trunk orientation to vertical. The final two experiments investigated whether gaze stability was enhanced during treadmill walking compared to passive replication of sagittal plane walking head motion (seated walking) for individuals with severe vestibular loss. Individuals with severe bilateral vestibular hypofunction displayed appropriately timed eye movements which compensated for head motion during active walking compared to seated walking. Timing information from the task of active walking may have contributed to enhancement of gaze stability that was better than predictions from passive head motion. This dissertation demonstrates: 1) the importance of visual sensory input for postural control during walking; 2) that visual information can be leveraged to modify trunk and whole body walking behavior; and 3) that the nervous system may leverage intrinsic timing information during active walking to enhance gaze stability in the presence of severe vestibular disease.