Burgon, Clare
(2023)
Exploration of apathy in people living with neurocognitive disorder.
PhD thesis, University of Nottingham.
Abstract
Background
Apathy is highly prevalent in people living with neurocognitive disorder (NCD). What constitutes apathy and how it is experienced by people living with NCD is poorly understood and under-researched, and there are no gold-standard measures of apathy. Apathy is associated with impaired functional ability, worse quality of life, conversion from MCI to dementia, increased care costs and carer burden, and may prevent effective participation in therapy programmes. It is important to understand what constitutes apathy, how to assess it, and identify possible mechanisms for apathy and potential treatment targets, in people living with NCD. However, the typical domain-based approach may be limiting our understanding of apathy. It is important to explore how individual indicators of apathy relate to one another. A broader exploratory approach is needed to understand how to conceptualise apathy, identify possible mechanisms of apathy, including an examination of how apathy is understood and experienced in people living with NCD. This thesis aimed to answer the following research questions: What measures of apathy are available and what is the quality of the evidence for their use with people living with NCD?; How should apathy be characterised and what are its conceptual boundaries?; What are the mechanisms and impact of apathy?
Methods
A comprehensive systematic review of the measurement properties of apathy measures was conducted. The ‘Consensus-based Standards for the Selection of Health Measurement Instruments’ approach was used to identify the available apathy measures and assess their quality of evidence and quality for use people living with NCD, to determine the most appropriate measure to use in a subsequent network analysis. Mixed methods enable the identification of possible mechanisms through quantitative methods, and corroboration and elaboration of these through qualitative methods, and so can be particularly useful for understanding mechanisms and processes. A convergent parallel-databases mixed methods study was conducted. A quantitative network analysis method was used to assess how indicators of apathy relate to one another, to examine the network structure of apathy and depression and to assess the impact of overlapping concepts including activities of daily living, executive functioning, physical impairment, frailty and age on the network. A qualitative interview study was conducted to explore how people living with NCD and their carers experience and understand apathy, how apathy develops, impacts their lives, and what influences this. The qualitative study was analysed using reflexive thematic analysis, whilst the network analysis study was analysed using a (cross-sectional) Gaussian Graphical Model network analysis approach. Participants were people living with NCD and their carers, sampled from a larger randomised controlled trial. 365 participants were included in the network analysis study, and 16 people living with NCD and 14 carers took part in the qualitative study. Findings were integrated in a narrative discussion.
Results
In the systematic review, fifty-seven publications regarding 18 measures and 39 variations met the eligibility criteria. Few studies involved people living with NCD or carers in the development of the measure. The Apathy Evaluation Scale and Lille Apathy Rating Scale had sufficient content validity, reliability, construct validity, and where applicable, structural validity and internal consistency in people living with NCD.
The network analysis study found that apathy indicators did not cluster into distinct domains, though apathy and depression indicators did cluster separately. Motivation and initiative formed the most important indicators of apathy, whilst energy and lack of cheerfulness were key to linking indicators of depression and apathy. Activities of daily living were independently associated with a number of apathy indicators, in addition to executive function and frailty, linking impairments and apathy.
The qualitative study found that apathy is experienced as an understandable response to the everyday difficulties people with NCD face. It can be understood to be a coping mechanism to preserve identity in the face of declining physical and cognitive abilities and associated threats to competence and autonomy, which is exacerbated by lack of opportunities and social support.
Conclusions
Numerous scales are available to assess apathy, with varying psychometric properties. New measures assessing apathy should be developed with the contribution of people living with NCD and carers, and could forego typical refinement approaches based on factor loadings, to develop a measure more suitable for future network analysis studies. In contrast to existing criteria for apathy, apathy may not be composed of distinct domains, and is proposed to be unavoidably linked to the wider social and environmental context in addition to cognitive and physical impairment. The exclusion of cognitive or physical impairment or lack of opportunity from the diagnostic criteria for apathy is problematic, given the importance of cognitive and physical impairment, social support and opportunity in apathy. Apathy indicators, regardless of the cause, may be improved by reducing task difficulty and effort, and by providing supportive and inclusive environments. Therefore, though apathy may occur as a result of neurodegenerative changes, it should not be considered in isolation from cognitive and physical impairment and the social and environmental context. A portion of this work took place during the COVID-19 pandemic which restricted the number of participants recruited and measures used.
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