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Title: Cognitive representations and attitudes as predictors of prosthetic use and recovery following lower limb amputation
Author: Callaghan, Brian G.
ISNI:       0000 0004 2668 7197
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2008
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Lower limb amputation is a common cause of activity limitations in Scotland with approximately 850 primary amputations being performed each year, 90% of which are caused by peripheral arterial disease. Approximately 65% of transtibial and 25% of transfemoral amputees are fitted with a prosthesis, however, of those fitted, around 40% are known not to use their prosthesis, or to use it only occasionally, following discharge from rehabilitation. Additionally, post-operative rehabilitation programs for lower limb amputees are focused primarily on improving mobility, despite the known impact of irrevocable limb loss on psychological states in addition to physical limitations. At present, however, there is an inadequate evaluation of psychological factors, either as dependant health outcome variables or as predisposing independent variables that may influence rehabilitation behaviours and other health outcomes, in amputees. There is a growing body of evidence to suggest that a full understanding of health- related behaviours, activity limitations and affective adjustment in chronic physical conditions requires consideration of the psychological processes mediating patients' responses to their condition. Social cognition models are used in health psychology as frameworks for guiding investigations into psychological variables that may determine health-related behaviours and outcomes. Among these models, the self regulation model and the theory of planned behaviour have successfully identified cognitive representations and attitudes to health behaviours, respectively, that have determined rehabilitation and health outcomes in other physical conditions. It was hypothesised therefore, that cognitive representations and attitudes towards prosthetic use (as well as psychological distress, functional limitations, sociodemographic and clinical variables) would play a role in determining being prescribed a prosthesis, subsequent prosthetic use, activity limitations, psychological distress and quality of life in lower limb amputees. Method A longitudinal predictive study was conducted at eight Scottish hospitals. Participants were assessed at recruitment (3-4 weeks post-operatively) using the predictor variables, which included cognitive representations, attitudes towards prosthetic use, pre-operative activity limitations, psychological distress and sociodemographic and clinical variables. They were then assisted to complete the outcome variables, in their own homes by a trained amputee visitor, at 1-month and 6-months post-discharge. Outcome variables included prosthetic prescription, prosthetic use, activity limitations, psychological distress and quality of life. Multiple regression equations were used to assess the extent to which the outcome variables could be predicted by the predictor variables. Results One hundred and sixty six amputees were recruited to the study, with 142 and 120 being retained at 1-month and 6-months follow-up, respectively. Being prescribed a prosthesis was predicted by social deprivation, level of amputation, diabetes and unilateral/bilateral status, but not by psychological variables. Significant attitudes towards prosthetic use models emerged for predicting prosthetic use, with normative beliefs x motivation to comply with NHS staff and family members being particularly influential. Significant cognitive representation models also emerged for predicting prosthetic use, with timeline cyclical (perceptions of symptoms fluctuating) and treatment control (beliefs about treatment efficacy) being the most prominent determinants. Their influence was stronger at 6-months than at 1-month. Depression predicted indoor prosthetic use at both follow-up times. In relation to predicting activity limitations, timeline cyclical and treatment control were again the most influential cognitive representation at both 1-month and 6-months. Emotional representations (distressing thoughts) also predicted activity limitations, but only at 1-month. Emotional representations were also prominent in predicting psychological distress at both outcome assessment times. No variables achieved significance for predicting quality of life. Discussion Many studies have attempted to identify factors relating to prosthetic use and other rehabilitation and health outcomes following lower limb amputation, however, these have focussed primarily on physical factors while psychological factors have been poorly represented. The social cognition models used in this study have provided useful frameworks for identifying psychological variables that predicted prosthetic use, activity limitations and psychological distress in amputees. The implications of these results are that this new knowledge raises the prospect of being able to a) identify patients whose psychological profiles render them at more risk of not rehabilitating as successfully with a prosthesis and not achieving favourable activity limitations and psychological distress outcomes, and b) formulate elements of acute psychological care aimed at increasing the number of patients making effective use of their prosthesis and achieving more successful activity limitations and health outcomes after being discharged from hospital. Further research should be aimed at developing new, or adapt existing, cognitive behavioural therapies to target the predictive psychological variables identifiyed in this study. The efficacy of these interventions could then be assessed in a randomised controlled trial.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral