Abstract
Introduction: Intermittent Claudication (1C) is a chronic vascular symptom of Peripheral Arterial Disease, in which blood flow to the leg muscles becomes Insufficient during free-living walking,resulting in cramp-like pain. Although previous research has highlighted the impact of 1C on physical function, many of these studies have tested patients in the laboratory and this is not always transferable to free-living walking. Few studies have considered the impact on free-living walking across different locations and the challenges encountered by individuals on an everyday basis, such as gradients.Purpose: To explore the location-based differences in free-living walking characteristics between individuals with and without 1C measured using an objective activity monitor and a Global Positioning System (GPS) device. Gradient-based outcomes as well as locus of free-living walking activity were calculated. In addition, the associations between physical activity measures, disease severity and Quality of Life were assessed.
Method: A series of three studies were conducted. The first was an exploratory study to ensure the validity and practicality of the equipment and questionnaires, including the development and testing of newly-devised questionnaires. The second study was a preliminary patient pilot study which examined the feasibility of using the methods with 1C patients. This data was used to develop cleaning techniques for the GPS data and to develop location- and gradient-based outcome measures. The final study was a case control study which compared free-living walking characteristics between individuals with 1C and gender-, age- and geography-matched controls without 1C, focusing on the newly-devised outcome measures. Seven-days continuous ambulatory monitoring was carried out using the activPAL™ activity monitor and location information was recorded using the AMOD AGL3080™ GPS device for 34 individuals with 1C and their 34 controls. Location coordinates from the GPS were combined with digital terrain maps to extract height data for each point. Event-based analysis was used on 28 pairs of participants who had a minimum of the same 4 days of GPS and activity monitor data available.
Results: Individuals with 1C walked for significantly less time and took fewer steps than controls. Additionally claudicants had fewer walking events per day and a lower cadence of walking.However the Event-Based Claudication Index (representing broken-up walking) was significantly lower in claudicants. By classifying walking events according to their location using GPS data, claudicants were shown to take significantly fewer steps across all location categories and walk less time 'at home' and both 'indoors' and 'outdoors' than controls, but not 'away from home'.Claudicants demonstrated a restricted locus of activity relative to controls. Claudicants spent significantly less time and distance walking whilst gaining height and losing height compared to controls. Similarly, claudicants had shorter and fewer events in which they gained/lost height. In terms of gradients, claudicants had a significantly lower cadence than controls for 'downhill'gradients only. Claudicants reported a significantly lower quality of life than controls and this was positively associated with physical activity 'away from home' 'outdoors' and with subjective measures of disease severity. Physical activity outcomes were negatively associated with disease severity; however locus of activity showed no association. IV
Discussion/Conclusion: This thesis highlights that individuals with 1C are being limited by their condition, and this is evident in their activity levels and walking characteristics. This was shown to be the case particularly when examining walking uphill and downhill. Combining activity monitor, GPS data and digital terrain maps has allowed the exploration of several novel outcome measures to categorise location. These findings have implications for clinical treatment, including the recommendation of undertaking free-living walking on inclines and declines.
| Date of Award | 2016 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Brian Ellis (Supervisor), Philippa Dall (Supervisor) & Malcolm Granat (Supervisor) |