Background: Diabetic peripheral neuropathy (DPN) is diagnosed clinically as a loss of sensation in the feet and affects over 2 million people in the UK. One of the functional effects of DPN is a decrease in standing stability giving rise to a risk of falls. In an attempt to stabilise in the mediolateral direction, people with DPN frequently walk with a wider base of support and stand with a larger stance width. This is often seen in the elderly and is not always beneficial for stability contributing to falls risk. Standing balance requires the integration of sensory information from somatosensory, vestibular and visual systems. Alterations in distal sensory input may result in a re-weighting of the effectiveness of remaining sensations in mediating a stabilising postural response; termed sensory re-weighting. Alterations in posture such as adopting a wider stance width and wearing Ankle Foot Orthoses (AFOs) may also affect sensory input as well as altering the mechanics of the ankle and hip joints. The impact of distal sensory loss on the sensory control of balance in people with DPN compared to the healthy population is unknown. Moreover, it is not known whether standing balance or the sensory control of balance is affected by the adoption of an increased stance width and wearing (AFOs) that restrict mediolateral ankle motion. A better understanding of the mechanisms underlying balance dysfunction in diabetic peripheral neuropathy and how it might be manipulated could inform the development of future interventions to improve balance. Aim: To explore the effects of ankle foot orthoses and stance width on standing balance and the sensory control of mediolateral balance in people with DPN and healthy controls. Objectives: To assess how mediolateral postural stability and the sensory control of balance is affected by (a) AFO use and alterations in stance width in healthy participants (study 1) (b) acute distal sensory loss in healthy participants (study 2) (c) chronic sensory loss in people with DPN and how this in turn is modulated by AFO use and alterations in stance width (study 3). Methods: Postural stability and the response to selective muscle vibration that stimulates muscle spindle afferents was measured by 3D motion analysis. Study 1 investigated the effects of stance width and AFOs on postural sway and the response to selective hip proprioception stimulation induced by vibration of the hip abductors in healthy participants. Study 2 investigated the effect of an acute reduction of somatosensory information induced by cooling in healthy participants on the response to ankle evertor and hip abductor vibration. This provided a model of the acute effects of sensory loss. Study 3 compared healthy people with people with chronic DPN. It investigated the impact on stance stability and whether there was a change in the postural response (gain) to ankle evertor and hip abductor vibration. It further explored the effect of altering the stance width and wearing an AFO on stability and the postural response to hip abductor vibration. Results: Study 1: In healthy controls postural sway was significantly reduced when wearing an ankle foot orthoses and when standing at wider stance widths. Whilst this was also seen during balance perturbation, trunk motion increased at larger stance widths. This could be the result of the AFO restricting ankle motion and affecting the interpretation of the hip vibratory input by the postural control system. Study 2: Experimental reduction in distal sensation by cooling resulted in a reduction in postural responses to ankle evertor muscle vibration. Conversely postural responses at the level of the hip, to proximal (hip) muscle vibration, significantly increased. Study 3: Baseline sway velocity was higher in people with DPN compared to healthy controls. Postural strategies were modified in the DPN group, with increased motion at more proximal segments of the shoulder and head. In both groups, AFO and stance width significantly reduced baseline sway velocity, and the size of postural responses (translations) to hip abductor muscle vibration. Conclusion: Alterations in stance width and the use of AFOs can affect postural sway and the response to selective proprioceptive stimulation. Whilst acute reductions in distal sensory loss are associated with sensory re-weighting of distal and proximal proprioceptive information this is not seen in people with chronic DPN, possibly resulting from long term adaptive changes in the multi-sensory control of balance. Novel differences were found in postural strategies between healthy and DPN groups. The increase in head and trunk motion in people with DPN may have a negative impact on visual acuity and therefore a risk factor for falls. In people with diabetic peripheral neuropathy AFOs and increased stance width led to a reduction in postural response size and postural sway. The effect of AFO on sway velocity was more pronounced in those with DPN at smaller stance widths. Clinically this suggests that an AFO could be used in those with diabetic peripheral neuropathy to slow down the velocity of sway and increase stability.

The extent to which sensory impairments in the foot, ankle and lower limb persist into the chronic phase of stroke is unclear. Furthermore, the extent to which these impairments influence walking, balance and falls is not well understood. This thesis investigated the prevalence, functional importance and measurement of lower limb somatosensory impairments in ambulatory people with chronic stroke. Methods This thesis comprised three studies: the first, a qualitative investigation, explored the views and experiences of people with chronic stroke (n=13). This led to the second study: a cross sectional observational study in which the prevalence, distribution and functional relevance of lower limb sensory impairments were investigated in chronic stroke participants (n=180) and healthy controls (n=46). The final study, informed by the findings from the first two studies, a “synthesis” review of current sensory measures and patient and carer involvement, developed and evaluated three novel, functionally oriented measures of lower limb somatosensory discrimination in chronic stroke (n=32) and healthy controls (n=32). Results People with stroke felt problems with foot, ankle and lower limb sensation affected their walking, balance and contributed to falls. Furthermore, sensory impairments in the lower limb are prevalent with up to 59% of chronic stroke survivors having a deficit of one or more somatosensory modality. Despite this, weak associations between traditional measures of tactile and proprioceptive sensation and walking, balance and falls were demonstrated. Novel, functionally oriented measures of tactile and proprioceptive discrimination were developed and evaluated. These measures were reliable and valid, showing greater sensitivity to predicting the presence of sensory impairments and had stronger associations with functional measures than traditional sensory tests. Conclusions This thesis has provided a comprehensive picture of lower limb somatosensory dysfunction in chronic stroke survivors. Sensory impairments persist into the chronic phase of stroke in the majority of stroke survivors. The extent to which such impairments influence functional ability warrants further investigation. The use of functionally oriented measures that assess higher-level somatosensation is encouraged.

Wong Pui Lam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 80-89). / Abstracts in English and Chinese. / Acknowledgments --- p.i / Abstract --- p.iii / Chinese Abstract --- p.v / Table of Contents --- p.vii / List of figures --- p.ix / List of tables --- p.xi / Introduction --- p.1 / Background of the Study --- p.1 / Statement of the Problem --- p.4 / Research Questions --- p.4 / Significance of the Study --- p.4 / Hypotheses --- p.5 / Assumptions --- p.6 / Delimitations --- p.6 / Limitations --- p.7 / Operational Definitions --- p.7 / Review of Literature --- p.8 / Introduction of Literature Review --- p.8 / Literature Review on Soccer --- p.9 / Introduction --- p.9 / Movements in Soccer --- p.9 / Soccer Injury --- p.9 / Design of Soccer Shoe --- p.15 / Playing Surface of Soccer --- p.18 / Summary --- p.19 / Literature Review on Perceived Comfort --- p.20 / Introduction --- p.20 / Perceived Comfort --- p.21 / Assessment of Perceived Comfort --- p.23 / Summary --- p.25 / Literature Review on Plantar Pressure --- p.26 / Introduction --- p.26 / Plantar Pressure --- p.26 / Assessment of Plantar Pressure --- p.27 / Summary --- p.31 / Summary of Literature Review --- p.32 / Methodology --- p.34 / Subject --- p.34 / Shoe --- p.34 / Experimental Design --- p.36 / Instrumentation --- p.40 / Procedures --- p.41 / Parameters --- p.44 / Data Reduction --- p.44 / Data Analysis --- p.46 / Results --- p.49 / Perceived Comfort Rating (Experiment 1) --- p.49 / Perceived Comfort Rating (Experiment 2) --- p.52 / Plantar Pressure (Experiment 2) --- p.55 / Relationship between Perceived Comfort Rating and Plantar Pressure (Experiment 2) --- p.63 / Discussion --- p.68 / Perceived Comfort Rating (Experiment 1 and Experiment 2) --- p.68 / Plantar Pressure (Experiment 2) --- p.71 / Relationship between Perceived Comfort Rating and Plantar Pressure (Experiment 2) --- p.75 / Limitations and Recommendations --- p.76 / Conclusion --- p.78 / References --- p.80 / Appendix A --- p.90 / Appendix B --- p.91 / Appendix C --- p.92 / Appendix D --- p.93 / Appendix E --- p.94 / Appendix F --- p.96 / Appendix G --- p.97 / Appendix H --- p.98 / Appendix I --- p.102 / Appendix J --- p.106 / Appendix K --- p.109

Deviations from normal foot structure are thought to result in hyper or hypo mobility preventing the foot from providing sufficient stability or mobility at appropriate times during the stance phase of gait. Such deviations in foot structure are often suggested as a risk factor for the development of common foot and ankle injuries. Though foot structure is believed to influence function its effect on foot motion and mechanisms thought to allow stability during the end of stance phase remain poorly understood. The purpose of this study was to determine the extent to which arch height affects foot kinematics during gait using a four segment foot model. Subjects included 17 healthy individuals with a wide range of arch heights and no past history of foot pathology. A three-dimensional motion tracking system was used to determine kinematics of the hallux, first metatarsal, forefoot, calcaneus and tibia during gait while subjects ambulated at a predetermined walking velocity of 0.78 statures/s. AP and lateral radiographs were used to determine coordinate system orientation for the first metatarsal, forefoot and calcaneus. The sagittal plane angle between the first metatarsal and calcaneus was used to represent foot structure. No association was observed between foot structure, as represented by arch height, and foot kinematics as represented by excursion or coupling during the stance phase of gait. This surprising result provides no evidence to support the assertion that foot structure influences mobility during gait in individuals without foot pathology. The kinematic patterns observed were highly consistent between individuals and provide new insight into the mechanisms underlying the formation of a rigid lever for pushoff at the end of stance phase. Supination, consisting of forefoot and first metatarsal adduction and plantarflexion along with hindfoot inversion, was found to occur at approximately 76 percent stance. Kinematic coupling associated with activation of the windlass mechanism is consistent with the concept of supination and occurs shortly after forward rotation of the first metatarsal and hallux dorsiflexion. In conclusion, deviation from normal foot structure appears to have little or no influence on foot mobility or intersegmental coupling due to activation of the windlass mechanism.

Thesis (M.Occ.Ther.(Occupational Therapy))--University of Pretoria, 2009. / Summary in English. Includes bibliographical references.

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 52-57). Also available via World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 185-194). Available also in a digital version from Dissertation Abstracts.

published_or_final_version / Nursing Studies / Master / Master of Nursing

No description available.

No description available.