The overall aim of this thesis is to contribute to the development and implementation of evidence-based physical activity promotion strategies for people with acquired brain injury (ABI). A randomized controlled trial (RCT) will furnish the highest level of evidence regarding the efficacy of a given intervention, but the immaturity of this area of research means that, currently, an RCT is not an appropriate research design. Therefore the purpose of the program of research presented in this thesis was to strategically contribute to the evidence base required to justify the conduct of a well designed RCT of an intervention promoting physical activity for people with ABI. By increasing participation in free-living, moderate intensity walking, people with ABI may reduce the oxygen cost of walking, thereby improving everyday functioning. The first study (presented in Chapter 3) evaluated a novel over-ground walking protocol in which a third party assists participants with ABI to reproduce previously self-selected comfortable and brisk walking speeds. Such a protocol could be used in conjunction with a portable indirect calorimetry to evaluate changes in oxygen cost of self-selected walking speeds over time. Thirteen people with ABI and related gait pattern impairment (age 31 + 8 yrs) completed two familiarization and two testing sessions. The first testing session used a self-paced (SP) protocol in which participants walked for 6 minutes at two self-selected speeds comfortable and brisk paces. The second, conducted one week later, used an externally-paced (EP) protocol in which participants were instructed to walk at the pace indicated by the test administrator, who verbally and visually guided the participant to walk at their previous self-selected comfortable and brisk paces. In each testing session participants wore a portable indirect calorimeter (Cosmed K4b2). Measures obtained were oxygen cost of walking (l.min-1) and distance walked (m). Analysis demonstrated that the EP protocol reproduced distances walked at comfortable and brisk speeds with a high degree of accuracy and that agreement between measures of oxygen cost obtained during the SP and EP protocols were acceptable. Steady-state oxygen uptake is characteristic of a constant workload and was elicited during both EP walking trials, indicating that walking speeds were constant throughout the walk trials. It was concluded that the EP protocol described is a valid means of assisting people with ABI to reproduce overground walking speeds and that the protocol would be useful for evaluating changes in the oxygen cost of those walking speeds that may occur over the course of an intervention. The purpose of the second study (presented in Chapter 4) was to evaluate the validity of a uniaxial accelerometer (MTI Actigraph) for measuring physical activity in people with acquired brain injury (ABI) using portable indirect calorimetry (Cosmed K4b2) as a criterion measure. Fourteen people with ABI and related gait pattern impairment (age 32 + 8 years), wore an MTI Actigraph that measured activity (counts.min-1) and a Cosmed K4b2 that measured oxygen consumption (ml.kg-1.min-1) during four activities quiet sitting (QS), comfortable paced (CP), brisk paced (BP) and fast paced (FP) walking. MET levels were predicted from Actigraph counts using a published equation and compared with Cosmed measures. Predicted METs for each of the 56 activity bouts (14 participants x four bouts) were classified (light, moderate, vigorous or very vigorous intensity) and compared with Cosmed-based classifications. Results indicated that Actigraph counts provide a valid index of activity across the intensities investigated in this study. For light to moderate activity, Actigraph-based estimates of METs are acceptable for group-level analysis and are a valid means of classifying activity intensity. The Actigraph significantly underestimated higher intensity activity although, in practice, this limitation will have minimal impact on activity measurement of most community-dwelling people with ABI as higher intensity activity is likely to be rare in this group. In the third study (presented in Chapter 5), 18 community-dwelling adults with acquired brain injury and a related gait pattern impairment (32.3 + 7.5 yrs) participated in an 8-week intervention promoting lifestyle physical activity. The aims were threefold: to evaluate the physical and psychosocial effects of the intervention; to assess whether the intervention increased the physical activity of participants; and to qualitatively evaluate the perceived effectiveness and acceptability of the intervention. Data were collected at six time points over 28 weeks: three pre-intervention, one each at 12 weeks prior (T1), 11 weeks prior (T2) and immediately pre-intervention (T3); and three post-intervention at immediately after (T4), four weeks after (T5) and eight weeks after (T6) the intervention. Physical outcomes measured were oxygen cost of comfortable and brisk-paced walking and maximum distance walked in three minutes. Psychosocial outcomes measured were SF-36, Depression Anxiety and Stress Scales (DASS), Rosenberg Self-Esteem Scale (RSES), Satisfaction with Life Scale (SWLS) and the Barriers to Health Activities for Disabled Persons (BHADP). Physical activity was sampled 6 days at T3, T4 and T6 and two measures were obtained Actigraph counts per day and total minutes of activity greater than or equal to moderate intensity. Semi-structured interviews were used to evaluate the perceived effectiveness and acceptability of the intervention. The intervention comprised weekly, home-based, interactive problem-solving sessions designed to identify and overcome barriers to activity and to promote walking, together with facilitation of a community based leisure activity of the participants choice. Results indicated that the intervention improved important aspects of physical and psychosocial health for community-dwelling people with ABI. Compared with mean baseline measures, improvements in oxygen cost of brisk walking and self-esteem occurred that were both clinically and statistically significant at T6 (p < 0.01). Significant changes in two subscales of the SF-36 and the SWLS also occurred, although they were not sustained at T6. Measures of physical activity increased but not to an extent that was statistically significant. Qualitative data were principally positive, with 100% of participants and their significant others indicating they would recommend the program to another person with ABI. Given the particularly low levels of physical activity in the ABI population, and the correspondingly large individual and community benefits of that will be accrued if their physically active behavior can be increased, the promising results from this program of research indicate that there is a strong justification for allocating the resources necessary to conduct a sufficiently powered, randomized controlled trial of a lifestyle physical activity intervention for people with ABI.
| Identifer | oai:union.ndltd.org:ADTP/290347 |
| Creators | Tweedy, Sean Michael |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
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