Moffatt, Claire Elizabeth (2019) The development of a novel positive health framework to improve the understanding of recovery after chronic subdural haematoma. PhD thesis, James Cook University.

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Abstract

The definition of health continues to be a topic of significant contention and interest. Human health was once considered the basic level of functional and metabolic efficiency required for a living organism. However, as our understanding of the human body has evolved, so has the conceptualisation of health and health research. Advancements in medicine have allowed empirical investigation into disease, illness, and ailments that affect human functioning. As such, the once neutral concept of health is now largely governed by a focus on disease and illness, and theoretical models of health have been established to inform these investigations.

The most widely accepted models of health are termed as the biomedical model of health, and the biopsychosocial model of health. Both models aim to understand the determinants of disease, illness or pathology. Whilst the biomedical model is inherently focused on only biological determinants of disease, the biopsychosocial model also considers the contribution of psychological and social factors that give rise to symptoms, illness, and pathology. In keeping with the disease-focus of each model, current health research and practice tends to focus on the negative determinants of disease and illness, such as mortality rates, morbidity rates, recurrence rates, and factors that hinder patient adherence to treatment protocols. There is a consistent focus on patients experiencing poorer outcomes, whilst those patients whom recover well, are seldom investigated.

Whilst the contribution of each of these models to epidemiological research has been insurmountable, the ability to conceptualise these models as cohesive health models is significantly limited. Both the biomedical model and the biopsychosocial model fail to acknowledge the importance of positive human experience and the factors that contribute to it. The inherent focus on the negative determinants of health, negates the importance of wellbeing as a contributing factor to positive a recovery. Evidence suggests that there are positive health assets that significantly contribute to positive outcomes after disease and illness, beyond disease-factors identified in conventional medical models. Therefore, a focus on the positive side of health may result in a far more cohesive understanding of disease and factors that contribute to a positive recovery.

The conceptualisation of health beyond the absence of disease is a guiding principle of Positive Health. Positive Health suggests that there are factors relevant to positive human experience that subsequently contribute to reduced disease risk, improved recovery after illness, and long-term well-being. If determined to be successful, a Positive Health approach may be able to identify positive health assets that contribute to a positive recovery after disease and subsequently identify targets for future treatment and intervention. Therefore, this thesis aimed to explore and determine the usefulness of a Positive Health approach to the understanding of a condition that has only been investigated from a biomedical perspective, with limited information regarding long-term outcome and well-being.

Chronic Subdural Haematoma (CSDH) is the most common neurosurgical condition in individuals with incidence rates estimated at 56 in 100,000. It involves the development of a substantial blood clot (>50mls) between the layers of skin surrounding the brain. Presenting symptoms include headaches, confusion, speech abnormalities and coma. CSDH has been considered a benign event rectified by neurosurgical intervention. The medical literature following CSDH has focused substantially on acute neurosurgical outcomes in the first few months post-injury. However, recent research suggests that patients may experience higher mortality and morbidity rates following a CSDH, with poorer outcomes related to age>65years, male gender, minor brain trauma, alcohol abuse, and anticoagulant and antithrombotic medication use. Limited research suggests a reduction in independence, overall health and life expectancy. Given the current aging population, incidence rates for CSDH are expected to increase significantly, placing a significant burden on healthcare services. Therefore, research is required to understand and inform long-term treatment and management of this health condition.

To determine the usefulness of a Positive Health approach to understanding outcome after CSDH, an existing Positive Health framework was used to explore health assets that contribute to a positive outcome among patients. Seligman's Positive Health was initially applied to CSDH literature to determine the viability of a Positive Health approach to understanding outcome and recovery (see Chapter 3). Seligman defines Positive Health as a state beyond the mere absence of disease which is definable and measurable. According to Seligman, Positive Health can be operationalised by a combination of excellent status on subjective, biological and functional measures and it is possible to use these measures to test whether positive health predicts increased longevity, decreased health costs, improves mental health, and reduced risk of disease. The conclusions from Chapter 3 suggest the potential of a Positive Health approach to understanding the biological, functional and subjective assets relevant to a positive recovery after CSDH.

For subjective health assets, limited evidence suggests that an absence of depressive symptoms significantly contributes to a positive recovery after CSDH. However, for biological health assets, existing evidence suggests that biological health assets including female gender, protein kinase p38y, non-smoking behaviour, healthy alcohol-use, nutritional diet, absence of anticoagulation/antithrombotic therapy. Finally, for functional positive health, existing literature suggests the contribution of health assets including optimal concentration and word recognition, prospective memory, adaptation to one's environment, and positive social relationships.

The conclusions from Chapter 3 demonstrate the potential of a Positive Health approach to understanding what constitutes a positive recovery after CSDH but further highlight the limited information describing outcome after this condition. In response to these limitations, this thesis used both a retrospective and prospective approach to explore Positive Health in the understanding of outcome after CSDH. outcomes of this research informed the development of a novel Positive Health framework presented in this thesis.

The first study (Chapter 4) consisted of an extensive retrospective study applying an existing Seligman's Positive Health framework to better understand health assets relevant to a good recovery after CSDH. The sample consisted of CSDH patients (n=51) previously admitted to the Townsville Hospital for neurosurgical intervention during the period of January 2003 to 2011. Comparisons were also made to a clinical control group (n=31) consisting of patients who had sustained other forms of intracranial haemorrhage, and a healthy age and gender matched control group (n=52). As per Seligman's Positive Health framework, a series of measures were included to assess subjective, biological, and functional health assets that combine to form a positive recovery after CSDH.

According to the findings, CSDH patients demonstrated significantly reduced health and well-being after injury compared to healthy, age and gender matched controls, as well as clinical controls. For subjective outcomes, CSDH patients demonstrated increased depressive symptomology compared to healthy controls (F(2,126)=9.05, p<.001, ƒ''=.394). For biological outcome, CSDH patients demonstrated significantly more comorbidities compared to healthy controls (χ² 2, N=86 = 35.47, p<.001). Finally, for functional outcomes, CSDH patients demonstrate impaired performance on daily functioning and independence compared to ICH patients and healthy-controls (F(2,126)=8.46, p=.001, ƒ'=.29, 1−β=.995), and reduced social well-being compared to healthy-controls (F(2,127)=14.32, p=.001, ƒ'=.444, 1−β=.91).

Additionally, a combination of positive health assets was shown to contribute to a positive recovery after CSDH. Biological health assets included age at the time of injury, not female but male gender, bilateral or right-sided CSDH, non-smoking behaviour, and low-risk alcohol use (Chapter 4, pp.77-80). Functional assets included optimal global cognitive functioning, high social functioning and greater independence in daily activities (Chapter 4, pp.80-84). Subjective health assets included high psychological well-being (Chapter 4, pp.84- 86). These positive health assets combined to form a profile of what constitutes a successful recovery after CSDH.

The findings of Chapter 4 supported the hypotheses and specific biological, functional, and subjective positive health assets were found to significantly contribute to the positive recovery of CSDH patients. Interestingly, health assets specific to Biological Positive Health and Functional Positive Health domains were found to be more relevant to a positive outcome after injury, whilst Subjective Positive Health was not considered to significantly contribute to a positive recovery. The contributions of this research were two-fold. First, the findings identified positive health assets that significantly contribute to a positive outcome after CSDH. Second, the conclusions from this research provide the first potential targets for the development of patient-centred treatment and rehabilitation programs for managing outcome after injury. Importantly, whilst efforts were made to adequately identify positive health assets in a retrospective sample, the application of a positive framework to a largely disease-focused breadth of data proved challenging resulting in limitations associated with this research. The limitations highlighted the need for a more inclusive and structure positive health framework for standardised use in empirical research.

The limitations of the first study prompted the development of a novel Positive Health theoretical framework for the understanding of health and disease (Chapter 5). The novel Positive Health framework was developed to address the limitations of existing ideas, including a lack of clearly defined terms, a lack of theoretical structure, and the absence of empirically measurable variables. Two objectives directed the development of the proposed novel framework of Positive Health; it is vital that the subdomains are organised into an evidence-based theoretical structure, and the ability to translate the framework into empirical research and practice should remain at the forefront of its development.

Experimental, observational, and clinical health research was extensively examined and deconstructed to inform the development of the framework. The findings from this extensive review informed the development of a novel Positive Health framework that was based on a human-systems approach to health. A clear theoretical structure was outlined with significant support from the literature, organising Positive Health into biological, functional and subjective domains. Additionally, the novel Positive Health framework provides a theoretical structure for each Positive Health domain, to adequately inform empirical research and ensure standardised methodological design.

The Biological domain of the novel Positive Health framework is underpinned by the theoretical debate of nature vs. nurture. Quite simply, is human functioning and behaviour determined by genetic inheritance and biological factors, or by an individuals environment. This thesis argues for the importance of both. Inherent genetic factors, and the influence of the environment and lifestyle factors are equally contributing factors to health and therefore represent the two equivalent subdomains under biological positive health. Static biological assets refer to the influence of nature and are largely predetermined. These may include gender, age, genetic factors. Dynamic biological assets refer to those variables that are influenced by the environment and are likely to alter, including exercise, body mass index, lifestyle factors. The biological domain is the building block from which function and subjective health may prosper.

The domain of functional health is organised into a hierarchy of human functioning. In line with literature describing the characteristics of a system, Functional Positive Health begins with the foundation required for human functioning described as cognitive assets and represents the basis for cerebral functioning. This domain may include cognitive assets relevant to attention, memory, executive functioning and global cognition. Cognitive Assets are the building blocks for an individual's social environment; optimal cognitive functioning if required for optimal human interaction. Therefore, Cognitive assets provide the basis for Prosocial Assets; the possession of skills and tendencies that support positive and rich relationships. Cognitive and prosocial assets then combine to allow our functioning in the wider environment. This is represented by person-environment-fit, or the ability for an individual to positive engage with their environment and adapt to any challenges. There is evidence that strongly supports the influence of each of these three subdomains in recovery after illness and have therefore been included in this domain.

Finally, with support from existing evidence, the novel Positive Health framework defines Subjective Positive Health as the optimal integration of one's own psychological functioning, emotional functioning, and perceived physical well-being. Subjective positive health represents a state of positive mental well-being where an individual realises their own potential, can cope with normal stresses of life, can work productively and fruitfully, and is able to contribute to their community.

The second study (Chapter 6) examined the utility of the novel Positive Health theoretical framework in a prospective investigation. The objective of this research was to further explore the positive health assets that combine to support a positive recovery after CSDH and determine their relationship with health-related outcomes. A sample of CSDH patients admitted to the Townsville Hospital for neurosurgical intervention were recruited to the study (n=114). The differential relationship between biological, functional, or subjective positive health assets and health-related outcomes were hypothesised. It was expected that biological health assets and functional health assets would significantly contribute to improved survival, reduced morbidity, improved global functioning, and reduced healthcare utilisation after CSDH. Subjective health assets were expected to contribute to reduced morbidity, improved global functioning, and reduced healthcare utilisation.

To determine the relationship between Positive Health assets and health-related outcome, the novel theoretical framework was used to measure variables relevant to short- and long-term mortality, morbidity after CSDH, global functioning, and independence after injury. The hypotheses were partially supported.

Biological health assets shown to contribute to the long-term survival of CSDH patients included: lower age ATOI (F(1,111)=5.317, p<.05, d'=.704), mild atrophy (χ²=3.814, p=.00), and lower scores on the Markwalder Neurological Grading system at discharge (χ²=15.266, p=.01). For Functional health assets, greater independence in activities of daily living measured on discharge was the only known functional asset to contribute to increased survival at either discharge or six months post-surgery. No significant differences or relationships were observed for Subjective health assets.

For Biological health assets and recurrence, patients of male gender were less likely to experience a recurrence (χ²=3.964, p=.046). Whilst no significant differences or trends were noted for Functional health assets and recurrence, a trend was identified for a subjective health asset with patients with greater emotional well-being and optimism were also at reduced risk of morbidity and recurrence after injury (F(2,13)=3.31, p=.60).

For global functioning, Biological assets including lower age ATOI (F(5,107)=4.87, p=.01, ƒ'=.305, 1−β=.975), no history of trauma (χ²=3.534, p=.056), absence of dementia (χ²=18.130, p=.001), dense haematoma appearance (χ²=7.655, p=.006), mild atrophy (χ²=16.969, p=.001), and low scores on the Markwalder Neurological Grading System contributed to improved functioning at six months post-surgery (χ²=28.262, p=.01). No significant differences were observed for Functional assets or Subjective assets.

For healthcare utilisation, Biological assets included lower age ATOI (F(5,108)=3.146, p=.011, d'=.611, 1−β=.865), absence of dementia (χ²=7.676, p=.01), haematoma density (χ²=5.145, p=.023), reduced atrophy (χ²=7.676, p<.006), and low scores on the Markwalder Neurological Grading System (χ²=19.95, p=.001). For Functional assets, greater preoperative independence was associated with reduced healthcare utilisation in the period following injury (χ²=5.60, p<.05), as well as lower scores on independence in daily activities (F(2,14)=3.438, p=.60). No significant differences were observed for Subjective health assets.

Functional assets including higher verbal fluency, greater preoperative independence and greater independence in activities of daily living, with patients being more likely to be discharged home as opposed to another hospital, rehabilitative centre, or nursing home. No significant differences were found for Subjective health assets.

Findings from this study (Chapter 6) indicate that Biological health assets were found to be most impactful, particularly in regards to survival after CSDH, whilst Functional assets were found to significantly contribute to morbidity, global functioning, and healthcare utilisation after CSDH. Evidence did suggest a relationship between specific Subjective health assets and morbidity after CSDH, however the relationship between these assets and healthrelated outcomes was weaker than expected. According to the findings from this study, specific positive health assets were found to significantly predict health-related outcomes among CSDH patients and further contribute to directions for future treatment.

Theoretically driven and empirically validated research is required for determining the use of a Positive Health approach to understanding health and disease. The implication of biological and functional health assets to recovery after CSDH was well-supported in this thesis and warrants further investigation. Despite the findings for Subjective Positive Health, further research into the relationship between psychological well-being, emotional well-being, and physical well-being should be conducted.

The accurate application and measurement of Positive Health assets in CSDH populations is vital. This clinical group consist of patients at risk of increased mortality rates and significant health decline, yet no current rehabilitation or treatment programs exist to manage their outcome or recovery. If successful, a Positive Health approach to understanding outcome after CSDH could greatly expand breadth of knowledge pertaining to this patient group and may inform the basis for the first successful patient-centred rehabilitation programs.

Item ID:	63548
Item Type:	Thesis (PhD)
Keywords:	chronic subdural haematoma; health outcomes; psychological assessment; traumatic brain injury
Related URLs:	https://researchonline.jcu.edu.au/58259/ https://researchonline.jcu.edu.au/60322/
Copyright Information:	Copyright © 2019 Claire Elizabeth Moffatt.
Additional Information:	Two publications arising from this thesis are stored in ResearchOnline@JCU, at the time of processing. Please see the Related URLs field. The publications are: Moffatt, Claire, Hennessy, Maria, Marshman, Laurence, and Manickam, Apukutty (2019) Long-term health outcomes in survivors after chronic subdural haematoma. Journal of Clinical Neuroscience, 66. pp. 133-137. Thomas, Piers A. W., Moffatt, Claire E., Rudd, Donna, and Marshman, Laurence A. G. (2019) S-100β in chronic subdural haematoma: prospective cohort study. Journal of Clinical Neuroscience, 67. pp. 145-150.
Date Deposited:	23 Jun 2020 04:51
FoR Codes:	11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110903 Central Nervous System @ 50% 17 PSYCHOLOGY AND COGNITIVE SCIENCES > 1701 Psychology > 170101 Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) @ 50%
SEO Codes:	92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920111 Nervous System and Disorders @ 50% 92 HEALTH > 9202 Health and Support Services > 920204 Evaluation of Health Outcomes @ 50%
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