Postural alignment and recovery of mobility after acquired brain injury

Abstract

Recovery of mobility after acquired brain injury (ABI) can be limited, with many people never regaining independence with key motor skills such as walking. Few investigations have explored mobility progress for people who are unable to walk unsupported. Postural alignment is not typically included in kinematic studies, and its association with recovery of mobility is not clear. The central aim of this thesis is to determine if improvement in postural alignment is associated with improvement in mobility for people with severe mobility impairment after ABI. The four studies in this thesis focus on this gap in the literature. To understand the impact of ongoing, severe mobility impairment after ABI, the thesis starts with a longitudinal, qualitative study exploring the significance of mobility for people with severe mobility impairment after ABI (Chapter 2). Relevant literature is then reviewed in a systematic review investigating the relationship between postural alignment and mobility (Chapter 3). Postural alignment was analysed in adults with severe mobility impairment after ABI and in healthy adults. This included development of a kinematic measure for whole-body postural alignment, the Postural Alignment and Dispersion (PAD) score (Chapter 4). Finally, a longitudinal, observational study of people with ABI who were unable to walk at eight weeks post-injury examined changes in their mobility over six months, and the relationship between mobility skills and postural alignment over time (Chapter 5). Key findings from the qualitative study (10 participants, 26 interviews) were that mobility impairment was devastating and that “small” improvements such as assisted walking or transfers without a lifting machine were critical for their wellbeing. Based on data from seven publications, the systematic review was unable to determine whether postural alignment is related to mobility after ABI. Three-dimensional kinematic data from 14 adults with ABI and 14 healthy participants were analysed to develop the new PAD score. The score quantified body segments’ displacement from upright alignment over the base of support, measured in the transverse plane. Postural alignment was measured in sitting and standing, with and without support from rails. Repeatability was demonstrated in all conditions in healthy adults using intraclass correlation coefficients (ICC, range 0.701 to 0.945), and in the three conditions with sufficient data (sitting conditions and standing holding rails) in adults with ABI (ICC range 0.614 to 0.912). Dispersion of body segments was greater in participants with ABI. The difference in mean PAD scores between samples was statistically significant in sitting conditions, with higher scores in participants with ABI, reflecting greater mean segment displacements from upright alignment. Over the six-month longitudinal study, adults with ABI (n=14) made significant progress with mobility based on scores on the Clinical Outcome Variables Scale (p=<0.001). Mobility improvement was significantly associated with improved postural alignment in sitting and standing, measured with PAD scores (p=<0.001 - 0.039). In conclusion, the findings of this thesis have shown that improvements in mobility can be crucial for those with severe mobility impairment after ABI, and that aspects of mobility other than independent walking are meaningful for them. Marked impairments of postural alignment were noted in adult participants with severe mobility impairment after ABI, and despite the extent of their limitations they made significant progress with mobility over six months. Results provide preliminary evidence to support clinical reports that improvement in upright postural alignment is associated with mobility progress after ABI. This gives a basis for further investigation of postural alignment in kinematic research and provides new evidence to promote attention to postural alignment in rehabilitation practice.