Everyday functioning, care and health-related quality of life

A range of other symptoms can also occur in HD, most notably unintended weight loss which is common and thought to be related to hypermetabolism (Aziz et al.,

2008; Robbins, Но & Barker, 2006). Autonomic system changes like excessive sweating may be less well-known but again, are not uncommon as there is research showing that presymptomatic and symptomatic individuals report more issues than non-HD controls in gastrointestinal, urinary, cardiovascular and (for men) sexual domains (Aziz, Anguelova, Marinus, Van Dijk & Roos, 2010). Sleep disruption and disintegration of the usual sleep-wake cycle (Morton, 2013) are also commonplace and can have a major impact on everyday functioning.

Indeed, the myriad changes associated with HD span the full spectrum of human behaviour and they slowly but inexorably progress over the long course of the disease. Deterioration may not be linear, uniform nor constant (Marder et al., 2000), and there is considerable variability both within and between individuals. The collective impact of these HD related changes on an individual’s functional ability is profound. Progressive loss of independence can be felt even early on in the disease as work and lifestyle can be affected, as well as driving (Devos et al., 2014). Over time further changes evolve, firstly in instrumental activities of daily living such as the ability to handle finances and household chores; eventually activities of daily living are compromised as patients need help with personal care. The most commonly used measures of functional ability are from the UHDRS (Huntington Study Group, 1996), specifically the Total Functional Capacity (TFC) score, where individuals are rated from 13 (normal function) to 0 (needing full-time care).

Functional ability and mood are key determinants of health-related quality of life in HD patients (Ho, Gilbert, Mason, Goodman & Barker, 2009). This latter is a patient-reported outcome that provides the overall perspective of the individual with respect to the impact of disease. Due to the heritability, complexity, and multifaceted repercussions of HD, generic health-related quality of life scales are unlikely to capture the full impact of Huntington’s (Ho et al., 2004). In a recent review by Mestre et al. (2018), commissioned by the International Movement Disorders Society’s Committee on Rating Scale Development, the Huntington’s Disease Health-Related Quality of Life (HDQoL) questionnaire (Ho, Horton, Landwehrmeyer, Burgunder & Tennant, in press; Hocaoglu, Gaffan & Ho, 2012) was the key HD specific questionnaire suggested. The HDQoL comes with a parallel version for carers and partners to provide their perspective on the patient (Hocaoglu, Gaffan & Ho, 2012).

The clinical experience of people living with HD as they navigate the health system is important in terms of how this affects everyday quality of life. Management and care can play an important part in mitigating disease impact as the symptoms of HD can be treated and managed by exploring the full arsenal of existing pharmacological options for individual complaints (Anderson et al., 2018; Schiefer, Werner & Reetz, 2015). While there remains a paucity of non-pharmacological interventions, particularly in the cognitive (Andrews, Dominguez, Mercieca, Georgiou-Karistianis & Stout, 2015) and psychological (Berardelli et al., 2015) domains, early work on multidisciplinary rehabilitation programmes (Zinzi et al., 2007), and particularly on exercise (Fritz et al., 2017) are promising. Further work is needed in non-pharmacological interventions to explore the concept of neuroplasticity in the context of HD and to understand how behavioural and environmental influences might impact symptoms, underlying processes and pathology'. Both behavioural and pharmacological approaches have a role to play and can be used in combination to enhance functioning and health-related quality of life.

While there has been limited success in identifying an effective disease modifying therapy for HD thus far, there is growing optimism with an increasing number of laboratory studies and clinical trials. In addition to pharmacological research, there is promise in Huntingtin protein lowering approaches such as gene editing, which aims to provide neuroprotection by intervening upstream to prevent the activation of pathology in the first place (Kieburtz, Reilmann & Olanow, 2018). As the momentum of HD-relevant research continues to increase, there is good reason to hope that this will transform the future of care, treatment, and the lives of countless individuals living with the presence or risk of HD, as well as their families.

Concluding remarks

Returning to the vignette of Marielle, a few years on from her father’s funeral, she soldiers on, dealing with her daily life while keeping up with scientific developments in HD as she watches and waits for what could be a clear indication of chorea - there are days when she wonders if this has already occurred, with her increasingly erratic movements. In addition to keeping a watchful eye on the latest scientific developments, she has also told her family and close friends, and has decided to take steps to get connected with the HD community. She now proactively seeks to take part in research studies and clinical trials as she tries to carve out a life on her own terms while waiting and hoping for a ‘cure’, if not for her then perhaps for her son, should this eventually be needed for him. She prioritises exercising regularly in order to do what she can to try to delay the effects of her increasingly compromised neurophysiology', and tries not to dwell too much on how badly affected her uncles are now. We leave her feeling just a little more accepting of life at present, even though she does not want to look too far into the future, and instead keeps herself busy living one day at a time, trying not to see HD every time she gazes at her young son.

HD is a life-changing disease on many different levels. In fact, the mere presence of HD in the family, rendering an individual at risk of this disease is in itself life-changing, not to mention the repercussions of having a parent, and possibly other family members affected by the disease. The consequences of a long-term multi-system brain disorder on a single individual cannot in reality be neatly parcelled into the motor, cognitive and behavioural categories, which are useful in clinical care and research. These seemingly discrete manifestations of disease will impact and influence related aspects of disease, and interact with the backdrop of personal history as they are played out on the real-world stage of a person’s

104 Aileen К. Но

evolving everyday life. We see in the vignette, a glimpse of the multi-generational burden shouldered by patients and their families, as they live with the shadow of HD, and so it behoves us to progress both scientific research and clinical care innovations, as the emergence of new behavioural interventions and disease modifying treatments cannot come soon enough.

Abbreviations

AES Apathy Evaluation Scale

BDI Beck Depression Inventor)'

BG basal ganglia

CAG cytosine-adenine-guanine

FAB frontal assessment batter)'

FDG-PET fluorodeoxyglucose-positron emission tomography fMRI functional magnetic resonance imaging

GABA gamma-aminobutyric acid

HADS Hospital Anxiety and Depressions Scale

HD Huntington’s disease

HD-CAB Huntington’s Disease Cognitive Assessment Battery

HDQoL Huntington’s Disease Health-Related Quality of Life questionnaire

HTT huntingtin gene

MMSE Mini Mental State Examination

MoCA Montreal Cognitive Assessment

MRS magnetic resonance spectroscopy

PBA Problem Behaviours Assessment

RBANS Repeatable Batter)' for the Assessment of Neuropsychological Status

SCOPI Schedule of Compulsions, Obsessions and Pathological Impulses

SDMT Symbol Digit Modalities Task

SIS Snaith Irritability Scale

TFC total functional capacity

UHDRS Unified Huntington’s Disease Rating Scale

Further reading

Dumas, E. M., van den Bogaard, S. J. A.. Middelkoop, H. A. M. & Roos, R. A. C. (2013). A review of cognition in Huntington’s disease. Frontiers in Bioscience (Scholar edition), 5, 1—18. Retrieved from http://europepmc.org/abstract/MED/23277034. doi:10.2741/ S355

McColgan, P. & Tabrizi, S. J. (2018). Huntington’s disease: A clinical review. European Journal of Neurology, 25(1), 24—34. doi: 10.1111/ene.13413

Nance, M. A. (2017). Genetic counseling and testing for Huntington’s disease: A historical review. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, 174(1), 75-92. doi: 10.1002/ajmg.b.32453

Nance, M. A. & Myers, R. H. (2001). Juvenile-onset Huntington’s disease - clinical and research perspectives. Mental Retardation and Developmental Disabilities Research Reviews, 7(3), 153-157. doi: 10.1002/mrdd. 1022

Paoli, R. A., Botturi, A., Ciammola, A., Silani, V., Prunes, C., Lucchiari, C.,. . . Caletti, E. (2017). Neuropsychiatric burden in Huntington’s disease. Brain Sciences, 7(6). pii: E67. doi: 10.3390/brainsci7060067

Papp, К. V., Kaplan, R. F. & Snyder, P. J. (2011). Biological markers of cognition in prodromal Huntington’s disease: A review. Brain Cognition, 77(2), 280-291. doi:S0278- 2626(11)00126-6

 
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