**Abstract**

Long-term partnerships are important as they can determine happiness, influence physical and mental health and lengthen one's lifespan. However, complex neurodegenerative conditions, such as Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), can disrupt long-term relationships and even lead to dissolution of the partnership. The majority of studies in this field have focused on exploring the effect of PDD and DLB on care partners' outcomes but the impact of these conditions on dyadic, long term relationships is less well understood. We conducted a series of studies with people with PDD or DLB and their caregiving life partners using quantitative and qualitative methods. We demonstrated that PDD and DLB has a tremendous impact on the caregiving life partners and reduces relationship satisfaction. We argue for more studies in this field and recommend that future research focuses on strengthening dyadic relationships, which can ultimately preserve relationships and delay institutionalisation of the person with PDD and DLB, which has cost saving implications.

**Keywords:** long-term relationships, Parkinson's disease dementia, dementia with Lewy bodies, spouse, carer, caregiver, stress-appraisal model

#### **1. Introduction**

The prevalence of neurodegenerative conditions, such as Parkinson's disease (PD), Alzheimer's disease (AD) and dementia with Lewy Bodies (DLB) is rapidly growing due to an ageing population. Of the people living with PD, the majority will develop cognitive impairment (PD-MCI) or dementia (PDD) within 20 years of their PD diagnosis. This has implications for the person with the condition, their care partner as well as the wider health and social care economy. Cognitive impairment and dementia are key factors contributing to increases in health care costs, admission to care homes and early mortality. Importantly, these costs can be significantly reduced by the care provided by an informal care partner, usually a family member or a spouse. Such informal care accounts for over £11.6 billion in the United Kingdom (UK) per year [1]. Care partners support the person with a neurodegenerative condition with managing their daily activities as well as their physical and neuropsychiatric symptoms; however, this can impact their mental, emotional, social, financial and physical health.

In this chapter we will examine the nature of the care relationship of long-term partners of people with PDD or DLB, including a theoretical basis for this relationship. We will also outline the impact of the care role with a focus on care burden, quality of life and relationship satisfaction. A deeper understanding of the complex issues surrounding long term care relationships in neurodegenerative conditions such as PDD and DLB is essential in ensuring appropriate support can be put in place.

### **2. Lewy body dementias (LBD)**

PD is a complex progressive neurodegenerative disorder characterised by multiple motor and non-motor symptoms. It affects about 10 million people worldwide and is the second most common neurodegenerative condition after AD [2]. A recent 'Global Burden of Disease Study' found that PD is one of the most rapidly growing neurological conditions for which the number of deaths, prevalent cases and disability-adjusted life years have doubled between 1990 and 2015 [3]. As a result, PD has now been termed 'The Parkinson Pandemic' [4].

While the primary clinical presentation of PD includes a number of motor symptoms including slowness of movement (i.e. bradykinesia), muscular rigidity, rest tremor, or postural instability, a variety of other 'non-motor' symptoms may also manifest. Predominant among these is cognitive impairment and other neuropsychiatric symptoms such as apathy and psychosis which can often be precursors to the onset of PDD [5].

In contrast to PDD, DLB initially presents with cognitive and behavioural symptoms and motor symptoms may not emerge until later in the course of the condition, or in some cases, not at all. PDD and DLB are jointly referred to as 'Lewy body spectrum disorders' [6, 7] or 'Lewy body dementia' (LBD), which is the term we use in this chapter.

#### **2.1 Dementia in PD (PDD)**

Dementia in PD (PDD) has become increasingly prevalent with nearly 80% of people with PD developing dementia within 20 years after receiving the diagnosis of PD [8]. PDD is characterised by deterioration in memory, attention, visuospatial functions, executive functions and occurrence of behavioural and psychiatric symptoms, such as apathy and hallucinations [9]. Low cognitive reserve, mild cognitive impairment at baseline, hallucinations and older age, and older age at onset, and the akinetic-rigid motor phenotype are among the main risk factors for developing PDD [9–11].

#### **2.2 Dementia with Lewy bodies (DLB)**

DLB is the second most common type of neurodegenerative dementia following AD with a prevalence of 5% of all dementia cases [12]. Pathologically, the distinctive feature of DLB is the appearance of the thread-like protein deposits containing pathologic alpha-synuclein (known as the Lewy bodies) which occur in the central, peripheral, and autonomic nervous system [13]. Symptoms of DLB include cognitive impairment (especially in visuospatial domains and executive function), fluctuating confusion, parkinsonism, visual hallucinations, sleep disturbances and apathy [14]. Recent evidence suggests that 'pure DLB' is less common than 'DLB with concurrent Alzheimer's pathology' due to the overlap of Lewy bodies and neurofibrillary tangles specific to AD [15]. However, cognitive decline is generally faster in DLB than in AD [16] supporting the notion that DLB is an independent disease entity. In 2017, the international clinical diagnostic criteria for DLB were updated and now include guidelines for differentiating between clinical features and diagnostic biomarkers [14].

**37**

*Long-Term Partnerships in Lewy Body Dementias DOI: http://dx.doi.org/10.5772/intechopen.86204*

and a distinction should be made on diagnosis.

**3. Wider impact of LBD**

impact of PD on the person.

Although PDD and DLB are generally considered part of the same disease spectrum, the initial clinical presentation may differ, due to the timing of the onset of cognitive impairment. However, this view has been challenged [17] and some scholars have concluded that PDD and DLB do not differ with regards to cognitive and neuropsychiatric profile, sleep and autonomic dysfunction, PD type and severity, neuroleptic sensitivity, and responsivity to cholinesterase inhibitors [18–22]. Nonetheless, further studies have demonstrated that significant differences exist between PDD and DLB such as in age of onset (PDD < DLB) [23], levodopa responsiveness (DLB < PDD) [24], neuropsychological test performance (DLB < PDD) [25], and neuropsychiatric presentation [26]. This supports the notion that PDD and DLB are separate clinical conditions but share a common underlying pathology

Both PD and LBD have a significant impact on the person with the condition, their life partner, and family, as well as on society, due to higher needs and dependency as a result of developing the illness. For the person with the condition, the progression of PD can worsen their health-related quality [27], particularly physical and social functioning, cognition, communication and emotional well-being [28]. The notion of adverse impact of PD on physical, social and role functioning is corroborated by a qualitative study which found that PD brings about many changes in emotions and feelings, including fears and uncertainty about the future but also highlights some benefits that PD may bring [29]. Despite the well-established association between subjective well-being and motor impairment, there is a growing literature suggesting that more emphasis should be paid to the positive aspects of well-being, specifically endorsing social support, socialising with other people with PD, engaging in physical activities and maintaining motor skills can contribute to life satisfaction, sense of accomplishment, autonomy and positive emotions in people with PD [27]. This suggests that future studies could focus on life satisfaction and psychological well-being, which could potentially diminish the negative

In terms of the wider impact of PD on society, the disease places a major socioeconomic burden with an estimated annual cost of £2 billion in the UK [30]. A recent report on the impact of living with PD revealed that the total financial costs per household exceeded £16,000 per year due to increase in health and social care costs and reduction in income [31]. Many care partners of people with PD also had to give up employment to be able to provide care for their partner, which led to loss of income [32]. As the severity of PD increases, the costs also rise and can be up to six times higher at the advanced stage (i.e. H&Y stage 5) compared to the initial stage (H&Y stage 1) [33]. These costs likely increase with disease progression due to the complexity of concomitant symptoms of PD, the increasing need for a care partner, and increased rate of admission to residential care homes. However, some of the costs could be partially saved by the help, care and support that family care partners provide to people with PD and LBD. Prince and colleagues [1] estimated that care providers save about £11.6 billion in the UK each year, which is increasing faster than the corresponding increase in formal health and social care costs [1]. Cognitive impairment in PD significantly increases the frequency of institutionalisation [34, 35] and increases healthcare costs even more than PD without cognitive impairment [36, 37]. Furthermore, mortality, which is already increased among

**2.3 Comparison of PDD and DLB**

#### **2.3 Comparison of PDD and DLB**

*Geriatric Medicine and Gerontology*

**2. Lewy body dementias (LBD)**

to the onset of PDD [5].

we use in this chapter.

**2.1 Dementia in PD (PDD)**

developing PDD [9–11].

**2.2 Dementia with Lewy bodies (DLB)**

and diagnostic biomarkers [14].

PD has now been termed 'The Parkinson Pandemic' [4].

place.

issues surrounding long term care relationships in neurodegenerative conditions such as PDD and DLB is essential in ensuring appropriate support can be put in

PD is a complex progressive neurodegenerative disorder characterised by multiple motor and non-motor symptoms. It affects about 10 million people worldwide and is the second most common neurodegenerative condition after AD [2]. A recent 'Global Burden of Disease Study' found that PD is one of the most rapidly growing neurological conditions for which the number of deaths, prevalent cases and disability-adjusted life years have doubled between 1990 and 2015 [3]. As a result,

While the primary clinical presentation of PD includes a number of motor symptoms including slowness of movement (i.e. bradykinesia), muscular rigidity, rest tremor, or postural instability, a variety of other 'non-motor' symptoms may also manifest. Predominant among these is cognitive impairment and other neuropsychiatric symptoms such as apathy and psychosis which can often be precursors

In contrast to PDD, DLB initially presents with cognitive and behavioural symptoms and motor symptoms may not emerge until later in the course of the condition, or in some cases, not at all. PDD and DLB are jointly referred to as 'Lewy body spectrum disorders' [6, 7] or 'Lewy body dementia' (LBD), which is the term

Dementia in PD (PDD) has become increasingly prevalent with nearly 80% of people with PD developing dementia within 20 years after receiving the diagnosis of PD [8]. PDD is characterised by deterioration in memory, attention, visuospatial functions, executive functions and occurrence of behavioural and psychiatric symptoms, such as apathy and hallucinations [9]. Low cognitive reserve, mild cognitive impairment at baseline, hallucinations and older age, and older age at onset, and the akinetic-rigid motor phenotype are among the main risk factors for

DLB is the second most common type of neurodegenerative dementia following AD with a prevalence of 5% of all dementia cases [12]. Pathologically, the distinctive feature of DLB is the appearance of the thread-like protein deposits containing pathologic alpha-synuclein (known as the Lewy bodies) which occur in the central, peripheral, and autonomic nervous system [13]. Symptoms of DLB include cognitive impairment (especially in visuospatial domains and executive function), fluctuating confusion, parkinsonism, visual hallucinations, sleep disturbances and apathy [14]. Recent evidence suggests that 'pure DLB' is less common than 'DLB with concurrent Alzheimer's pathology' due to the overlap of Lewy bodies and neurofibrillary tangles specific to AD [15]. However, cognitive decline is generally faster in DLB than in AD [16] supporting the notion that DLB is an independent disease entity. In 2017, the international clinical diagnostic criteria for DLB were updated and now include guidelines for differentiating between clinical features

**36**

Although PDD and DLB are generally considered part of the same disease spectrum, the initial clinical presentation may differ, due to the timing of the onset of cognitive impairment. However, this view has been challenged [17] and some scholars have concluded that PDD and DLB do not differ with regards to cognitive and neuropsychiatric profile, sleep and autonomic dysfunction, PD type and severity, neuroleptic sensitivity, and responsivity to cholinesterase inhibitors [18–22]. Nonetheless, further studies have demonstrated that significant differences exist between PDD and DLB such as in age of onset (PDD < DLB) [23], levodopa responsiveness (DLB < PDD) [24], neuropsychological test performance (DLB < PDD) [25], and neuropsychiatric presentation [26]. This supports the notion that PDD and DLB are separate clinical conditions but share a common underlying pathology and a distinction should be made on diagnosis.
