Niemann-Pick disease type C (NPC) is a rare, genetic neurovisceral disease with a clinical incidence of approximately 1:100,000 [1
]. The clinical features of NPC include progressive loss of vision, hearing, muscle co-ordination and mobility. Cognitive decline leading to early-onset dementia can occur resulting in premature death in most people [2
]. Symptoms are heterogeneous and can arise at any point between early childhood and late adulthood and progress at different rates [1
]. NPC is classed as a life-limiting condition as there is no cure, and the only approved disease-specific drug available is Miglustat (Zavesca®
; Actelion Pharmaceuticals Ltd), which is offered for the treatment of progressive neurological manifestations [2
Living with any life limiting disease brings difficulties but living with a rare disease generates unique challenges for both the person diagnosed and their carers, and can be an isolating experience [3
]. Bury’s [4
] concept of biographical disruption suggested that an individual’s sense of self, social interactions, and daily life are disrupted by the illness experience. Illness can be characterised as a disturbance to the narrative flow of individuals’ lives, and episodes of ill health can represent significant change and can be viewed as a threat to this constructed self-narrative [5
]. When related to NPC, a disruption may feel permanent due to there being no cure, never allowing a return to life prior to the diagnosis; thus necessitating a change in a person’s biography and self-concept [4
]. Yet, Carel [6
] argued that it was possible for one to experience wellbeing in spite of illness. Thus, living with illness does not necessarily mean a wholly negative disruption and instead could be seen as something that could bring positive consequences, self-discovery and self-development [7
]. This illustrates the complexity of the illness journey and that there are numerous factors to take into account when considering the impact living with NPC has on a person’s QoL.
The concept of QoL is a highly valued focus of research and consideration within clinical practice. Despite this popularity, the lack of consensus on the definition of QoL is a source of confusion [9
]. Arguably one of the most respected definitions of QoL is the World Health Organisation’s (WHO) which describes it as being “individuals’ perceptions of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns” (p. 1404) [10
]. It is therefore multi-dimensional in its outworking and is understood as a “broad ranging concept affected in a complex way by the person’s physical health, psychological state, level of independence, social relationships, personal beliefs and their relationship to salient features of their environment” (p. 1) [11
]. With no qualitative research being conducted on understanding the experiences of living with NPC, it was important to prioritise focus on the “individuals’ perceptions” of what life with NPC means, in order to garner the nuances of the illness experience.
Accomplishing this necessitates an engagement with broader philosophical constructs and frameworks that can be used to understand such phenomena. An interaction with other theories that seek to broaden the scope of enquiry and ask more fundamental questions about how human beings understand the world about them is needed. There is a need to step back from the traditional fragmented components of what makes QoL, and subsequently what are used in QoL measurements and instead start first by considering the depth to what constitutes life in all of its quality from an ontological perspective, an issue deeply embedded in what it means to be human. Arguably a stronger emphasis on the developmental process may provide a more robust basis for QoL scales based on lived-experience in conjunction with theoretical models that aim to provide the fullest explanation possible as to what it is to live with illness.
Todres, Galvin and Dahlberg’s [12
] existential-phenomenological theory of lifeworld-led care explores how individuals live in relation to time, space, body, others and mood; a holistic outlook in which human beings understand the world around them. The lifeworld, as introduced by Husserl [13
], and Heidegger [14
], is a concept that represents the world as meaningful and relational, one that can be experienced and lived [15
]. Todres and Galvin [17
] discussed six dimensions that represent constituents of the lifeworld, intertwined within one another, yet holding certain nuances of lived experience. The dimensions are temporality, spatiality, intersubjectivity, embodiment, identity and mood (see Table 1
for an explanation of the dimensions of the lifeworld). Arguably, many of the principles within pre-existing QoL domains complement the lifeworld-led care constructs. However, lifeworld-led theory allows for a more open, less-constrained view, which incorporates the shared and unique dimensions of individuals’ experiences that are central to their QoL: something which is particularly important when looking at a rare disease about which we know very little [12
Elements of the lifeworld adapted from Todres et al. [12
Refers to time as it is humanly experienced, as a story through which we give order to our existence. One may have feelings of hope or opportunity. Others may feel sadness as opportunity is taken away from them
How humans live in meaningful ways; moving and living as this body. Meaning is given to our bodily existence. For example, our senses provide meaning to us, our body and the space it fills physically reacts and changes when faced with different experiences
Meaning is given to relationships, society, culture and that we are in the world with others and the ways we relate to individuals who we meet in our worlds can be very important to our meaningful living
An ontological security of being able and feelings of ‘I can’. Or feelings of lack of ability and uselessness; feelings of being an object, trying to fit into impersonal systems
Meaning is given to places, objects and situations that we hold in significance in daily living. A sense of adventure may be felt or a sense of restriction. The interpretation of the spaces in which people live and the stimuli by which they are surrounded
Mood has been defined as shaping our one’s spatial, temporal, intersubjective horizons and is intimate to how we find ourselves. Mood leads individuals to categorise and prioritise experiences in certain ways. Understanding the influence of mood in relation to the elements of the lifeworld will help secure an understanding of the quality of lived experience
In order to understand the markers of QoL for people living with NPC, one must explore and understand the impact of living with illness on the lifeworld of a person. As Bunge [18
] argued: “A better understanding of the quality of life calls for more intense theoretical and methodological work rather than an increase in the amount of social and environmental statistics… data without ideas are sterile when not misleading” (p. 65). Therefore, the current study sought to develop age-appropriate, disease-specific QoL scales based on the lived experiences of people living with NPC using Todres, Galvin and Dahlberg’s [12
] lifeworld-led care theory. These scales would be developed for the assessment of individuals who have NPC to enable healthcare professionals to better engage with patient’s wellbeing and to provide a useful measure of outcome in clinical and drug trials [19
Twenty-three parents/carers completed the NPCQLQ-C (child age in years mean = 8.61; S.D. = 4.22). Twenty parents/carers completed the NPCQLQ-A (adult age in years = 33.4, S.D. = 12.2). The sample comprised of 18 males; 20 females with NPC. One child’s and 4 adult’s gender were not reported. Mean proxy-rated NPC severity rating was 4.26 (S.D. 2.89) for children and for 4.45 (S.D. 2.23) for adults.
Item reduction and reliability of the NPCQLQ-C—QoL scale for children
Floor and ceiling effects were checked and no items were removed. Inter-item correlations revealed nine items highly correlated with each other; 5 of these were removed. Removal decisions were made in line with the results of the cognitive interviews; participants felt that some items were too similar, for example: “My child looks forward to new experiences in the future” and “My child is excited by the prospect of taking part in special occasions”; for other items, some felt that they were not relevant, such as “My child feels at peace with themselves”.
Item-total correlations were run and eight items were removed because they did not correlate with the total score (correlations of 0.1 or 0.2) or because they had a negative item-total correlation. Upon reflection, these items could be interpreted differently by each participant, thus did not provide a direct relationship between a high score measuring high QoL. Cronbach’s α
of the remaining 15 items was 0.925. A full list of items is reported in Table 5
. These items were summed and correlated with the item asking respondents to rate the severity of NPC in the child they were caring for. A higher severity rating significantly correlated with poorer QoL with a large effect size (r
= − 0.094).
Final items included in the NPCQLQ-C
Because of NPC, my child’s mobility has been affected
My child enjoys spending time with their friends
Because of NPC, my child struggles to hold things in his or her hand
Family routines make my child feel secure
My child enjoys playing with their toys or equivalent
I think my child feels like they cannot do things other children their age can do because of NPC
My child feels content about their physical health
I think my child feels like their relationships with their friends have changed because of NPC
My child feels comfortable with their body
Changes to our home environment have made day to day living easier for my child
My child is excited by the prospect of taking part in special occasions
My child appears to be sad
My child experiences times of frustration regarding their symptoms of NPC
My child copes well when things change at home
My child generally enjoys daily life
| || |
Item reduction and reliability of the NPCQLA-A—QoL scale for adults
Floor and ceiling effects were checked and no items were removed. Inter-item correlations revealed nine items highly correlated with each other and 5 of these were removed. Items were removed based on results from the cognitive interviews. Participants felt that some items were too similar, for example: “They feel content in day to day life” and “On the whole they feel content”; for other items, some felt that they were not relevant, for example: “In general, they feel that their physical state does not allow them to do the things they want to do.”
Item-total correlations were run on the remaining 33 items. Three items were removed because they did not correlate with the total score (correlations of 0.1 or 0.2) or they had a negative item-total correlation. Again upon reflection these items could be interpreted differently by each participant, therefore did not provide a direct relationship between high score and high QoL. Cronbach’s α
of the remaining 30 items was 0.947, indicating excellent internal consistency. A full list of items is in Table 6
. These items were summed and correlated with the item asking respondents to rate the severity of NPC in the person they were caring for. A higher severity rating significantly correlated with poorer QoL with a large effect size (r
= − 0.080).
Final items included in the NPCQLQ-A
The person with NPC feels supported in daily life
They feel that others do not always accept them
They feel hopeful when they think about the future
They feel motivated every day to achieve what they want to achieve
They feel that NPC has affected their social interactions
They feel that their body does not allow them to do things that they want to
They feel that they do not relate to other people
They find is easy to make new friends
They feel isolated
The person with NPC feels content when they think about the past
They feel content with their body and how it works
They feel in control of the present
They feel uncomfortable with the busyness of the world
They enjoy being in busy environments
They feel that sometimes other people do not understand them
Because of NPC they are not able to do the things that they would like to do
They feel in control of their life
How people view them is important to them
They feel confident in who they are as a person
They sometimes like to hide away from the world
They feel that friendships have changed over time
They have good relationships with healthcare staff such as doctors and nurses
They sometimes feel that they would like to have closer relationships with others
In general, they feel well
They feel disconnected from society
The person with NPC often feels low
They enjoy being part of the local community
They feel overwhelmed by different situations
The person with NPC would describe themselves as being an independent person
On the whole, they feel at peace
Adopting a phenomenological approach to explore the experiences of living with illness allowed for a richer understanding of how QoL is impacted upon when living with NPC. Using the elements of the lifeworld enriched our understanding of participants’ subjective experiences which then ensured the items included in the scale represented participants’ worlds when living with NPC. The initial reliability tests demonstrate the excellent internal consistency of the items in the scales for children and adults living with NPC. This information could be used to direct healthcare to more appropriate areas and to provide information for patients, parents/carers and healthcare practitioners on the effectiveness of drug treatments and other health-related interventions for those living with NPC.
The NPCQLQ-C items focused on the embodied experience of living with NPC, both in terms of the ‘objective’, physical manifestation of NPC, and the subjective, in terms of children’s contentment with being in their body. Prognosis varies but people who display neurological symptoms in childhood have been shown to deteriorate faster compared to those who become symptomatic later on in life [27
]. Items around whether children could play with their toys or whether NPC had affected their embodiment were shown to be important to a child’s QoL in that they could no longer take part in activities they could previously and the frustration this may arouse.
The NPCQLQ-A items focused more on the intersubjective sense of self and how this related to the temporal element of the life they once knew before their diagnosis with NPC, compared to the life they are now living. Many of the adults diagnosed with NPC had to leave employment and their social relationships had changed. For many, a change in identity was felt, and this led to spells of anxiety and depression due to the life they felt they had lost. Although many of the adults had better physical health than children with NPC, the impact on QoL could be greater, highlighting the complexity of the effects of this life-limiting condition on a person’s QoL and how this is not necessarily directly associated with the physical/objective body. Without explicitly exploring each element of the lifeworld, these nuances in people’s experiences may not have been identified.
Furthermore, drawing on the lifeworld theory means that both measures, the NPCQLQ-C and NPCQLQ-A are theoretically underpinned by an existential-phenomenological theory which transcends the individual. This also means that we have been able to go beyond concepts of QoL used in more ‘traditional’ measures. The intention of such a design is to prioritise the concerns of the individuals involved by first exploring the nature of their experience and moreover, to examine the meanings those people attribute to their experiences. This is especially valuable when working with such a rare condition because it then means that these meaningful experiences, rather than preconceived notions from other QoL scales, are used as the starting point for a measurement that can then be used in clinical practice and research.
Using this method may help people who are answering the questionnaire to be reflective, which in turn allows for concrete experiences to come to the fore rather than relying on what might be construed as more abstract concepts of QoL. This too aids healthcare professionals and researchers in understanding more about the lifeworld of their patients and the impact of living with NPC on their everyday lives. At the heart of this lifeworld-led approach is a commitment to humanising healthcare, i.e. ensuring that we treat the whole person rather than simply the condition. This study has highlighted the significance of how living with NPC may affect the patient’s sense of self and bodily identity rather than purely focusing on the physiological impact. These scales could be used as a guide in advancing healthcare and policies to better engage with the illness experience in a way that humanises care [28
]. This approach has aimed to be sensitive to what really matters to people living with NPC. The next part of the process will be to assess the validity of both the NPCQLQ-C and NPCQLQ-A in a comparative analysis with other validated QoL scales.
Implications for practice
It is important for healthcare professionals to have a more in-depth understanding of the impact of living with NPC on a patient’s QoL. Understanding patients’ and families’ experiences of living with NPC is an under-researched area which could be revolutionary in shaping healthcare professionals’ approaches to treatment for NPC and the impact of those treatments on a person’s QoL. Both the NPCQLQ-C and the NPCQLQ-A provide a robust ‘measurement’ or representation of the more subjective, experiential impact of NPC on an individual’s QoL. Working in a way that prioritises subjective experience and offers a more humanising approach to care would enable services to deliver support that focuses on meaningful person-centred care.
A key concern for this work is the small numbers of participants that completed the QoL questionnaires. However, with such a rare condition this is not surprising. For both the NPCQLQ-C and the NPCQLQ-A, nearly 50% of the diagnosed population in the UK completed a questionnaire, which proportionally offers a good representation of the diagnosed population. In addition, condition-specific scales have been criticised for their narrowness in focus, because they neglect to measure more general outcome variables [29
]. However, it is important, especially in rare diseases, to understand the issues that are specific to people living with that condition and very little is known about NPC in this respect. Condition-specific scales measuring QoL are more useful in detecting changes in a condition over time compared to a generic scale [30
]. This allows for the domains of QoL that are important to the population in question to be described and quantified [19
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