Variable Visual Stimulus as a Novel Approach for Gait Rehabilitation

Deterioration in walking performance as a result of disease or simply as a result of aging is a serious threat to independence in older adults. In this project, the investigators propose an innovative visual stimulus, based on advanced mathematical and biological theories, with which older adults can walk in time to improve their walking. The investigators' goal is to apply this simple, cost-effective, and novel gait rehabilitation therapy across all populations who have difficulties walking, e.g. stroke patients, fallers or those who undergo joint replacement.

Walking synchronized to a visual stimulus is commonly used for gait rehabilitation, and has been shown to alter gait parameters such as stride length and stride time in a variety of patient populations. Typically, the patient is instructed to walk by stepping on lines or other markers placed on the ground presented in a fixed, invariant distance with each other. Whilst improvements in gait parameters have been observed in these experimental conditions, the investigators submit that a fundamentally different approach could lead to much greater benefits. The investigators' laboratory has successfully shown that walking to an invariant stimulus, with no variability, runs contrary to the natural stride-to-stride fluctuations (i.e., gait variability) that are known to exist in human gait. The investigators propose that the elimination of variability from gait, as is the case when walking with invariant external cueing, will not provide the movement abilities needed by individuals with reduced mobility to navigate the real world, unpredictable environments. In this project, the investigators propose an alternative approach to rehabilitation of gait disorders with respect to external cueing that takes the natural variability of healthy gait into account. The investigators have previously shown that young and older adults when walking to an invariant stimulus, display diminished natural stride-to-stride fluctuations. Preliminary data has also shown that the natural stride-to-stride fluctuations that exist in healthy gait are altered with aging, but can also be restored to levels similar to young adults when walking to a Variable Visual Stimulus. The investigators proposed solution is then to transform the standard invariant visual cueing paradigm by using a Variable Visual Stimulus that reflects the variable movement patterns found in healthy gait. This is because the presentation of our Stimulus will be variable, but it will not be random. There will be a pattern contained within the presentation of our Stimulus that is based upon the patterns found in healthy young adults. This project will investigate the long-term effects of viewing an invariant, a random and a variable visual stimulus on gait variability in older adults. Furthermore, the investigators will investigate the retention effects at 1- and 3-months of an 8-week program. The central hypothesis is that older adults who are at risk of falling will demonstrate greater improvements in gait variability and adaptive gait tasks when walking with a Variable Visual Stimulus that reflects the variable movement patterns found in healthy gait. The impact of this project will be transformational regarding gait rehabilitation for older adults who are at risk of falls. This simple, cost-effective method would be accessible to all gait rehabilitation clinics requiring only ubiquitously available glasses.

Eligibility Criteria:
Inclusion Criteria:

* Be able to provide informed consent.
* Be able to walk independently without an assistive device.
* Not suffer from neurological disease.
* Not suffer from any lower limb disabilities, injuries or disease.

Exclusion Criteria:

* If diagnosed with a pathology that directly affects the musculoskeletal system such as rheumatoid arthritis, neuropathy or myopathy, vertigo, joint replacement, diabetes, stroke or other vascular problems, scoliosis, uncorrected vision problems,major surgery in the last 6 months, or acute illness.
* Any neurologic conditions or lower limb disabilities or disease.
* History of seizures, migraines or headaches, or are visually impaired.
* Subjects unable to walk unassisted or unable to perform 10 minutes of continuous walking.