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Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Health and Rehabilitation Sciences

Supervisor

Hunter, Susan W.

Abstract

The main objective of the present dissertation was to expand our understanding of the inter-relationship between cognition and mobility in people with lower limb amputations (PLLA). Study 1 systematically reviewed the literature to assess the effects of dual-task testing on the balance and gait of PLLA. A total of twenty-two studies were included. Overall, PLLA demonstrated a disproportionately greater dual-task effect than controls, characterized by increased sway velocity and reduced pace and rhythm, and increased asymmetry when balance or walking was paired with a secondary task. Additionally, the dual-task effect was not influenced by differences in etiology, level of amputation, or experience with a prosthesis. Study 2 examined the association between balance confidence, a proposed cognitive distractor, and basic walking abilities in community-dwelling people with unilateral transtibial level amputations. Forty-four people participated in Study 2, completing a questionnaire on balance confidence and an assessment of functional mobility. This study concluded that decreased balance confidence was independently associated with a longer time to complete the functional mobility test in both the single-task and dual-task conditions. Study 3 evaluated the association of cognitive function on tests of physical function in PLLA at discharge from inpatient prosthetic rehabilitation. Tests included examinations of global cognitive status, processing speed, executive function, and balance confidence. Physical function was assessed through gait velocity, dynamic balance, and functional mobility. Data from twenty-two participants demonstrated that better global cognitive status and executive function were independently associated with faster gait velocity and greater functional mobility for both conditions of single-task and dual-task, yet this was not observed for dynamic balance. Moreover, no association was observed between processing speed and balance confidence and any of the tests evaluated. PLLA are optimal candidates for dual-task balance and gait research as they are often being cognitively and physically challenged during ambulation with a prosthesis. The present findings are novel and provide evidence on the interplay between cognition and mobility in PLLA. Further research studies examining cognitive-motor capacity and its relationship to important markers of rehabilitation progress and future success are warranted in this group of people.

Summary for Lay Audience

Over half of people with lower limb loss fall each year. Falls have dire physical and emotional consequences, including fractures and a concern for falling that lessens quality of life. People with lower limb loss often express that they have to think about every step they take with a prosthesis. One way to test both thinking and physical abilities is by asking people to do two things at once, or dual-task. In real-life, we tend to dual-task often such as when walking and talking. However, many questions remain unanswered as to how thinking abilities and physical abilities interact with each other in people with lower limb loss. The present research project is made up of three studies. The first was a scientific review of existing research on how dual-task testing affects balance and walking in people with lower limb loss. A total of 22 studies were included for review. Dual-tasking in people with lower limb loss resulted in imbalance, and slower walking speeds, fewer steps, and increased walking unevenness when compared to healthy adults. The second study evaluated the relationship between having confidence in performing activities without losing balance and basic walking abilities. Study 2 concluded that having a low balance confidence was related to taking a longer time (worse function) to complete an L-shaped walking test in both simple walking and dual-task walking conditions. The last study examined the relationship between different tests of thinking abilities on the performance of a selection of tests for physical abilities (i.e., balance and gait) in individuals new at using a prosthesis. Study 3 found that better overall thinking abilities were related to faster walking speeds and taking less time to complete an L-shaped walking test in both single-task and dual-task conditions. The three research studies provide new information in people with lower limb loss related to the inter-relationship between how they think and how they move within their surroundings. Future studies should seek to answer if the results of dual-task tests assist with predicting long-term outcomes such as social participation, quality of life, and falls.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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