Abstract
Approximately 80% of stroke survivors experience walking problems (Alguren et al., 2010). These walking problems arise not only from the neurological damage caused by stroke itself, but also from secondary cardiovascular and musculoskeletal consequences of disuse and physical inactivity (Aqueveque et al., 2017). Regaining walking ability is a primary goal in stroke rehabilitation, however, nearly 40% of stroke survivors remain unable to walk independently at three month post-stroke (Preston et al., 2011). Among those who do regain walking ability, persistent gait abnormalities, such as reduced walking speed and increased gait asymmetry, are common (Patterson et al., 2008, Rozanski et al., 2020). Therefore, understanding the stroke-related factors associated with walking speed and gait asymmetry is crucial for designing more tailored and effective interventions.Despite the clinical significance of gait asymmetry in post-stroke rehabilitation, its relationship with stroke-related impairments in ambulatory stroke survivors remains insufficiently explored in the literature. While Lauziere et al. (2014) attempted to explore these associations, their topical review was unable to draw definitive conclusions due to the variability in measurements of both impairments and gait asymmetry. To date, no existing review has systematically synthesized evidence on stroke-related factors and their associations with gait asymmetry. To address this gap, Chapter 2 presents a systematic review and meta-analysis, which evaluates existing research papers and quantifies the relationship between stroke-related factors and gait asymmetry.
The systematic review and meta-analysis presented in Chapter 2 found that lower limb motor and sensory impairments, as well as the overall motor performance, were the factors most strongly associated with temporal asymmetry, while spasticity and/or contracture were the strongest association with spatial asymmetry. Although the meta-analysis identified significant associations between overall lower limb impairments (combined motor and sensory deficits) and gait asymmetry, the evidence specifically examining sensory deficits alone was insufficient to draw definitive conclusion. The studies included in the review assessed different sensory modalities, including light touch, joint position sense (via the Fugl-Meyer Assessment Lower Extremity (FMA-LE)), ankle joint position sense error (using an electronic goniometer), and motion sense (thresholds of detection and awareness). However, the heterogeneity in sensory assessments and measurement methods made it difficult to synthesize findings, potentially reflecting a historical emphasis on motor impairments in stroke research, with less focus on sensory dysfunction and its role in gait asymmetry.
Given the potential influence of sensory deficits on gait asymmetry, further research is needed to explore their specific contributions. Among sensory deficits, proprioception is one of the most commonly affected modalities after stroke, but the understanding of proprioceptive deficits after stroke remains relatively under-researched. To address this gap, Chapter 3 investigated proprioceptive deficits after unilateral stroke, and sought to determine the impact of stroke on ankle proprioception on both affected and less-affected sides at different post-stroke time points. Additionally, by comparing ankle proprioception on the less-affected side with that of age-matched healthy participants, the study in Chapter 3 aimed to investigate the possibility of stroke-related changes in proprioception on the less-affected side, a factor often overlooked in previous studies. Finally, the Active Movement Extent Discrimination Apparatus (AMEDA) was used to investigate ankle proprioception, as it is a proven ecologically valid and fully instrumented assessment tool. The findings of Chapter 3 demonstrated that ankle proprioception declined over time in both the affected and less-affected lower limbs following a unilateral stroke, with proprioceptive acuity on the less-affected side diminishing linearly in a similar manner to the affected side. A 10% reduction in ankle proprioception was observed in the acute phase, followed by a further 8% decline from the acute to chronic phases. While pre-stroke factors (e.g., prior ankle injuries, pre-stroke activity level) may have also influenced post-stroke proprioceptive acuity, the significant linear decline in both limbs suggests that factors in the post-stroke environment, such as relative disuse, likely contributed to these persistent deficits.
Currently, there is limited research specifically examining the relationship between proprioceptive deficits in the foot and ankle and walking ability after stroke. A better understanding of the extent to which proprioceptive deficits are associated with walking ability could provide valuable insights for guiding post-stroke rehabilitation strategies. If improved ankle proprioceptive acuity is associated with better walking ability, it could support the development of proprioception-targeted interventions in clinical rehabilitation. Thus, Chapter 4 aimed to 1) investigate the effects of side (affected vs. less-affected) and movement direction (inversion vs. plantar flexion) on ankle proprioceptive acuity after stroke and compare ankle proprioceptive acuity across stroke survivors with different levels of walking ability, categorized as household, limited community, and community walkers. The findings of Chapter 4 demonstrated that after stroke, ankle proprioceptive acuity was lower on the affected side compared to the less-affected side. Additionally, stroke survivors demonstrated higher ankle proprioceptive acuity in plantar flexion movements than in inversion movements. Overall, stroke survivors with higher ankle proprioceptive acuity tended to have higher walking ability, highlighting the importance of ankle proprioceptive acuity in walking ability after stroke. However, as this study did not perform correlation or regression analyses, the strength and nature of the relationship between ankle proprioception and walking ability remain unclear.
Although Chapter 4 provided some evidence supporting an association between ankle proprioceptive acuity and walking ability, the effects of ankle proprioceptive deficits on functional outcomes (balance and walking ability) in stroke survivors remain an open question due to limited research and inconsistent findings in literature. To examine this, Chapter 5 aimed to quantify the relationship between ankle proprioception (measured in weight-bearing conditions) and functional outcomes (balance and walking ability) in stroke survivors. The study in Chapter 5 used correlation (r) and regression analyses (r²) to determine the extent to which ankle proprioception predicts balance and walking ability. Additionally, it investigated proprioception on both the affected and less-affected sides, examining biaxial movement directions (plantar flexion and inversion) to provide a more comprehensive understanding of how ankle proprioception contributes to functional recovery after stroke.
The findings reported in Chapter 5 highlight the potential role of ankle proprioception in post-stroke rehabilitation. Moderate associations were observed between ankle proprioceptive acuity and both measures of balance (using the Berg Balance Scale) and walking ability (using the Timed Up and Go test and the10-Meter Walk test) in individuals with stroke. Notably, ankle proprioception for inversion movement on the affected side independently predicted balance and walking ability, accounting for a significant portion of the variance in these functional outcomes.
Taken together, the findings in this thesis improved understanding of lower limb proprioceptive deficits after stroke and their associations with walking and balance. These findings also highlighted the potential role of incorporating proprioceptive assessment and training into stroke rehabilitation.
| Date of Award | 2025 |
|---|---|
| Original language | English |
| Supervisor | Jeremy WITCHALLS (Supervisor), Elisabeth PRESTON (Supervisor) & Gordon WADDINGTON (Supervisor) |