Thesis
Reference
The burden of normality: a model of psychosocial adjustment after deep brain stimulation for Parkinson's disease
BAERTSCHI, Marc
Abstract
Deep brain stimulation (DBS) has become a leading surgical treatment for patients diagnosed with Parkinson's disease (PD) whose response to traditional dopaminergic medication is no longer optimal. Despite significant motor improvement, patients undergoing DBS for PD (PD-DBS) continue facing various issues impairing their quality of life (e.g., maintain of non-motor symptoms, appearance of new symptoms, difficulties to find adapted stimulation parameters). In addition to these medical reasons, psychosocial maladjustment has been recently considered a potential cause for perceived dissatisfaction after PD-DBS. Yet, no theoretical model has been proposed so far to account for the role and dynamics of psychosocial adjustment in the DBS process. This thesis attempts to apply to PD-DBS a theoretical model of psychosocial adjustment, the burden of normality (BoN), initially developed in epilepsy. Five studies are presented in this regard. The BoN is directly addressed through two studies; first, a literature review on the possible correspondences between the model and psychosocial issues after PD-DBS and; second; a [...]
BAERTSCHI, Marc. The burden of normality: a model of psychosocial adjustment after deep brain stimulation for Parkinson's disease. Thèse de doctorat : Univ. Genève, 2018, no. FPSE 722
DOI : 10.13097/archive-ouverte/unige:112573 URN : urn:nbn:ch:unige-1125731
Available at:
http://archive-ouverte.unige.ch/unige:112573
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Section de psychologie
Sous la direction du Professeur Nicolas Favez
The burden of normality: a model of psychosocial adjustment after deep brain stimulation for Parkinson’s disease
THESE Présentée à la
Faculté de psychologie et des sciences de l’éducation de l’Université de Genève
pour obtenir le grade de Docteur en Psychologie
par Marc Baertschi
de Vernier (GE)
Thèse No 722
Genève Décembre 2018
01-311-174
The burden of normality: a model of psychosocial adjustment after deep brain stimulation for Parkinson’s disease
Marc Baertschi
Candidat au titre de Docteur en Psychologie
Membres du jury
• Professeur Nicolas Favez, Université de Genève
• Professeur Martin Debbané, Université de Genève
• Docteure Alessandra Canuto, Fondation de Nant
• Professeur Pierre Burkhard, Université de Genève
• Professeur Alexandre Berney, Université de Lausanne
Table of contents
Foreword ... 1
Introduction ... 3
Parkinson’s disease... 3
The staging hypothesis. ... 4
Living with PD. ... 6
Psychosocial maladjustment in advanced PD. ... 7
Deep brain stimulation ... 9
Dissatisfaction following DBS. ... 11
The burden of normality model ... 13
The syndrome. ... 15
Expectations. ... 17
Precursory conditions. ... 18
Manifestations of psychosocial maladjustment ... 19
Couple satisfaction. ... 20
Illness representations. ... 23
Aims of the thesis ... 27
Studies presented in the thesis ... 28
Empirical section ... 31
Study 1 ... 33
Study 2 ... 66
Study 3 ... 87
Study 4 ... 102
Study 5 ... 118
Discussion ... 132
Summary of study results ... 132
Clinical application of this thesis ... 136
Conclusion ... 140
References ... 141
Appendices ... 179
Appendix A ... 179
Appendix B ... 189
Acknowledgments
I would like to express my deep gratitude to my thesis director Professor Nicolas Favez for his excellent guidance throughout this project, which has given me a glimpse of what it takes to become a university professor. I would have never been able to complete this thesis without his flexibility and intelligence to accommodate my complex professional and personal situation.
I am grateful to Doctor Alessandra Canuto and Professor Martin Debbané for accepting to be members of the thesis commission, and to Professor Pierre Burkhard and Professor Alexandre Berney for accepting to be members of the thesis jury. Similarly, I would like to thank Professor Martial Van der Linden for having accepted to be part of the initial
composition of the thesis commission. I also wish to acknowledge the help provided by the Swiss National Science Foundation, without whom undertaking this project would not have been financially and logistically possible.
I owe more than this thesis—almost my entire career in psychology—to Doctor Kerstin Weber and Doctor Alessandra Canuto, who have not only provided me with the opportunity to practice psychology again but also to define myself as both a clinician and researcher.
Their guidance and friendship have been pivotal during the course of this project. I hope that this thesis will be considered as a means to give them back the confidence and trust placed in me.
By the same token, I have thought and conceptualized this entire work in close
collaboration with Doctor João Flores Alves Dos Santos, whose advice and guidance have been essential to complete this project successfully. Way beyond this thesis, his friendship and clinical insight have helped me to become a better researcher and clinician. I would like to thank him for his unwavering support.
I also take this opportunity to underscore the indispensable role played by the
“Méthodologie et analyse de données” research group at the Faculty of Psychology of the University of Geneva in the realization of my project. By allowing university students to access their classes online and providing them with high-quality support material, I was able to continue working on my thesis when I could not be physically present at the university.
What this research group does for students is of the utmost importance and I can do no other than encouraging the Faculty to continue backing it. And when, despite this great help, statistics remained all Chinese to me, I was lucky enough to rely on the assistance of Professor Paolo Ghisletta, whom I would like to thank for his availability and kindness.
Although I acknowledge being its central protagonist, this thesis does not boil down to an individual trajectory and numerous people have provided support, directly or indirectly, during the past years and notably at my workplace. My thoughts and thanks are dedicated in this regard to my dearest colleagues and friends Francesca Arpone, Laura Frambati, Simona Toma, Michalina Radomska, Alessandra Costanza, Luca Leardini, Eline Tombeur, Anne- Françoise Pott, Karinne Pluchart, Rita Hurni, Julie Gaspoz, Celina Maragoto, Sofia
Athanasiou, Audrey Demierre, Naba'Ï-Al-Huda Yassin, Gabriella Perroud, Aline Mauguin, Julie Vandorpe, and Luca Scuderi.
This thesis project has been a five-year endeavor, which has of course impacted my private life. Without the precious support of significant people around me, none of all this would have been possible. Therefore, I would like to express my deepest thanks to my parents, siblings and their families, who patiently endured my mood swings. I owe very much to my uncle, Bernard Baertschi, who has paved the family way in research through a brilliant career in medical ethics—a topic of direct interest for the present thesis—and helped me to keep confidence when times were hard. I am also very happy to be able to count on incredible friends who have kindly helped me remember that I used to have a social life once and do not
seem to be too mad at me for not calling them back. Finally, I am very grateful to Weijia and Lian, who have ultimately given me the strength necessary to carry out and complete this project.
1 Foreword
Back in the last months of 2012, I was benefiting from a comfortable position as a sports journalist at the Swiss Telegraphic Agency, covering the matches of the Swiss basketball national team and the London Olympics with undeniable enthusiasm. Nothing seemed to predestine me, a few months later, to enroll in a Ph.D. program with the aim of exploring the consequences of brain surgery on patients suffering from a chronic disease. And yet, unstable perspectives in the world of the media—notably the print media, unfortunately verified at this date—and a sense of incompatibility of this demanding job, in which most events take place at night or during the weekend, with a family life, made me take the decision to re-orientate my professional path. During the summer of 2011, I had had a very nice part-time working experience at the Service of Liaison Psychiatry and Crisis Intervention of the Geneva University Hospitals (HUG)—in reality, this was my first professional experience in healthcare. I knew that I could take advantage of my interest in research to stand out in the competition with other psychologists in a field where many aspire to do clinical work uniquely. Towards the end of 2012, I renewed contact with my former boss at the HUG, Doctor Kerstin Weber, who offered me a one-year contract as research assistant with the explicit goal to help Professors Alessandra Canuto and Pierre Burkhard drafting and
submitting a grant application to the Swiss National Science Foundation (SNF) to study the psychological predictors of quality of life in patients undergoing deep brain stimulation for Parkinson’s disease. At this time, I had never heard about deep brain stimulation and I naively associated Parkinson’s disease with nothing more than tremor and aging. I nevertheless took up the challenge: we submitted the application and, in the fall of 2013, were granted a funding by the SNF allowing us to hire a Ph.D. candidate. Professor Alessandra Canuto offered me the opportunity to be this candidate, which I arrogantly accepted under the condition that I was trained as a clinician as well. It looked that we had an agreement! Along with Doctor Kerstin
2 Weber, she kept her word and allowed me to continue my clinical education. My career project also received indirectly the support of the Faculty of Psychology of the University of Geneva, which agreed that I registered at the same time in a Ph.D. program and a clinical Master of Advanced Studies. Five years later, I am happy to notice that I have been able to keep on making correspondences between research and clinical work, and in this regard, I feel that I have not betrayed my personal commitment to psychology and to the patients who have pinned their hope on our work to help them getting better. I wish that this thesis could be considered as a token of my gratitude to all those who have believed in my project.
3 Introduction
Parkinson’s disease
Idiopathic Parkinson’s disease (PD) is a neurodegenerative condition without curative treatment. In Europe, it affects 108 to 257 inhabitants per 100,000 (Von Campenhausen et al., 2005) and this rate steadily rises with age, ranging from 41 per 100,000 for individuals aged 40-49 years to 1903 per 100,000 for persons older than 80, with few location- or gender- related differences (Pringsheim, Jette, Frolkis, & Steeves, 2014). Considering global population ageing, the management of PD, including symptoms, patients and caregivers support, is a major public health problem that will take on greater importance.
The causes of PD are unknown but hypothesized to stem from a combination of genetic and environmental factors (Rizek, Kumar, & Jog, 2016). PD articulates around four cardinal symptoms affecting motor function (Jankovic, 2008). First, bradykinesia pertains to slowness of movements, which affects the performance of daily activities in general, reaction times, movement spontaneity, or induces loss of facial expression. In addition, akinesia may occur in the form of sudden and transient loss of movement; these motor blocks are also known as
“freezing”. Second, tremor appears at rest and predominantly concerns body extremities.
About 70% of patients diagnosed with PD had rest tremor at onset, and it is likely that this symptom will eventually appear in most patients during the course of the disease. Postural tremor may also occur. Third, rigidity refers to movement resistance and lack of fluidity, and is often associated with pain and postural deformities. Finally, postural instability usually occurs at an advanced stage of the disease, increasing the risk of falls and injuries.
In addition to these motor problems, non-motor symptoms appear throughout the disease progression. These non-motor symptoms may be neuropsychiatric—including depression, anxiety, hallucinations, and dementia—, autonomic, gastrointestinal, sensory, related to sleep disorders or not belonging to a specific category like fatigue and weight problems (Chaudhuri,
4 Healy, & Schapira, 2006). Considering this
important and various number of symptoms, the clinical picture of PD may differ greatly among individuals.
The staging hypothesis.Given the current state of knowledge, extrapyramidal motor symptoms of PD are assumed to be the result of the degeneration of dopaminergic neurons in the pars compacta, a portion of the substantia nigra located in the midbrain (Figure 1). In PD, this neuronal loss, predominant in the ventrolateral part of the pars compacta, is associated with presence of Lewy bodies and Lewy neurites stemming from aggregation of α-synuclein protein (Dickson et al., 2009).
In addition, neuronal loss occurs in other brain regions at different stages of the disease.
It has notably been demonstrated that, at an early stage, this loss involves the
presupplementary motor area, the caudal intralaminar thalamus and the mesocortical system. Cell degeneration also affects the
cholinergic basal forebrain and mesopontine systems, the hypothalamic hypocretin system, and the upper brainstem serotonin system but later in the disease progression (Halliday, Lees,
Figure 1 Semi-quantitative assessment of the density of pigmented neurons in the SNpc.
Left images show templates of the distribution of pigmented neurons in healthy controls (A) and in patients with PD with mild (B), moderate (C), or severe (D) loss of pigmented neurons. The severity of the pigmented cell loss in PD is not homogeneous and should be primarily assessed in the ventral and lateral regions of the SNpc (boxed area in A), to correlate with the severity of motor symptoms.
Right images show examples of the density of pigmented neurons in this region from actual cases (×40 magnification) in transverse haematoxylin and eosin-stained sections. 3n=exiting 3rd nerve fibres. cp=cerebral peduncle. PD=Parkinson’s disease. R=red nucleus. SNpc=substantia nigra pars compacta.
(Figure and legend retrieved from Dickson et al., 2009).
5
& Stern, 2011; MacDonald & Halliday, 2002). Assuming that α-synuclein aggregations only occur in projection neurons with predominantly poor-myelinated axons, Braak and colleagues (Braak et al., 2003, 2006) have hypothesized a 6-stage process underlying PD development in which Lewy pathology spreads from cell-to-cell transmission (Figure 2).
• In stage 1, the process begins with formation of Lewy bodies and neurites in the dorsal motor nucleus of the vagus nerve, in the medulla oblongata, and in anterior olfactory structures including the olfactory bulbs;
• In stage 2, these lesions impair and expand into other brainstem nuclei;
• In stage 3, these lesions develop into basal portions of the midbrain and forebrain including the amygdala and the pars compacta of the substantia nigra;
• In stage 4, the temporal mesocortex is affected;
• In stage 5, Lewy pathology gains progressively access to the temporal neocortex;
Figure 2 Stages 3 to 6 of pathological changes associated with sporadic PD in 100 µm sections immunostained for α -synuclein.
The darkened tissue areas indicate the presence of PD- related lesions that are already recognizable with the naked eye from stage 3 onward in hemisphere sections.
a: Hemisphere section of a case at stage 3. The arrow points to a single spot showing the central subnucleus of the amygdala. Allocortical, mesocortical, and neocortical areas are uninvolved at this stage.
b: Hemisphere section of a stage 4 case. More severe involvement of the amygdala (arrow) is accompanied by beginning affection of the anteromedial temporal mesocortex (arrowhead).
c: Hemisphere section from a stage 5 case. A thick network of Lewy neurties emerges in the superficial layers of the anteromedial temporal mesocortex, and projection neurons located in the deep layers contain Lewy bodies (arrowhead). The disease process encroaches upon the related insular and cingulate mesocortex (asterisks). From the mesocortex, the pathology progresses into the high order association fields of the neocortex. The immunoreactivity gradually tapers off the closer it gets to the secondary and primary fields of the temporal neocortex (arrow). Note that the gyrus of Heschl along the superior temporal convolution is unaffected.
d: Cortical involvement gains additional momentum in stage 6. Areas of the insular, cingulate (asterisks), and temporal mesocortex (arrowhead) continue to show strong immunolabeling. The cortical changes increase both in severity and extent. The disease process reaches even the secondary and, in advanced stage 6 cases, primary neocortical fields, as seen here from the mild affection of the primary auditory field in Heschl’s gyrus (arrow).
(Figure and legend retrieved from Braak et al., 2006).
6
• In stage 6, PD reaches secondary and primary areas. Lesion density continues increasing, which is notably observable in the pars compacta of the substantia nigra that appears emptied from melanoneurons.
According to this staging hypothesis, motor symptoms of PD should begin to appear clinically at stage 3 as a consequence of the development of Lewy neurites in the pars compacta of the substantia nigra (Braak et al., 2006). However, non-motor symptoms can be detected at earlier stages as demonstrated with olfactory problems, rapid eye movement behavior disorder, constipation and depression (Chaudhuri, Odin, Antonini, & Martinez- Martin, 2011). Neuroanatomical correlates of non-motor symptom appearance for each stage of Braak’s staging hypothesis have also been identified (Wolters & Braak, 2006).
Thus, these findings deconstruct the popular belief that PD boils down to motor symptoms.
They show that the disease progressively spreads to various brain regions, leading to the appearance of different types of motor and non-motor symptoms. From this perspective, PD appears as a highly complex and multisymptomatic condition.
Living with PD. Although non-motor symptoms of PD are experienced as more disabling in the long run than motor symptoms (Hely, Morris, Reid, & Trafficante, 2005), preferential treatment remains substitutive dopaminergic therapy targeting motor improvement. Despite initial benefits, such treatment induces negative side effects as dosage is increased to respond to the natural progression of PD. Thus, patients and their neurologists must face different challenges in, on the one hand, finding and managing the most appropriate medical treatment and, on the other hand, dealing with the consequences of medication/disease progression that impacts various aspects of patients’ life. This section reflects on the two most frequently prescribed medical treatment, namely levodopa and dopamine agonists, as well as the consequences of PD progression on patients’ daily living.
7 Used as PD treatment since the late 1960s, the neutral acid amino precursor for dopamine L-DOPA—or levodopa—has allowed patients to significantly improve their quality of life in reducing motor symptoms (Obeso, Olanow, & Nutt, 2000). Taken orally in combination with several enzyme inhibitors to circumvent early metabolism, levodopa is absorbed in the small bowel and transported through the blood-brain barrier by specific amino acid transporters before being transformed into dopamine by the aromatic L-amino acid decarboxylase.
Dopamine is subsequently stored in presynaptic terminals and released in the synaptic cleft by the arrival of an action potential (Camargo et al., 2014; Hollingworth, Rush, Hall, & Eadie, 2011; Koller & Rueda, 1998).
Dopamine agonists are of various kinds which can be divided into ergoline (e.g., bromocriptine, cabergoline, dihydroergocriptine, lisuride, pergolide) and non-ergoline (apomorphine, piribedil, pramipexole, ropinirole, rotigotine) derivatives (Reichmann et al., 2006). Contrary to levodopa, dopamine agonists have a direct action on dopamine receptors without earlier transformation (Tan, 2003), and all have an affinity to D2 dopamine receptors (Brooks, 2000). In early PD, levodopa has proven to result in slightly better motor outcome than dopamine agonists (Gray et al., 2014). Dopamine agonist may nevertheless be initially prescribed instead or in combination with levodopa to delay adverse effects, notably
dyskinesia, dystonia and short periods of freezing that accompany long-term use of levodopa (Stacy & Galbreath, 2008). Yet, use of dopamine agonist may also trigger impulse control disorders such as pathological gambling, hypersexuality, binge eating, and compulsive eating (Voon & Fox, 2007).
Psychosocial maladjustment in advanced PD. In addition to the direct effects of symptoms related to PD itself and medication side effects, patients must deal with indirect consequences of the disease progression on their everyday life. In other words, they may experience difficulties of psychosocial adjustment, which has been defined as the “healthy
8 rebalancing by patients to [the] new circumstances” of life induced by a chronic disease (de Ridder, Geenen, Kuijer, & van Middendorp, 2008, p. 246). For these authors, psychosocial adjustment depends on the patient’s capability to live with the consequences of the disease, to experience positive affects and limit negative affects, to avoid psychiatric disorder, to sustain a functional status (e.g., being employed), and to have satisfaction and wellbeing in various life domains.
Patients with advanced PD are at higher risk of not meeting all the criteria favoring adequate psychosocial adjustment. Psychiatric comorbidity is more prevalent in PD patients than in the general population; authors have reported presence of psychotic symptoms, deterioration of self-image and self-esteem, perceived stigmatization, and mood worsening (Caap-Ahlgren & Lannerheim, 2002; Haahr, Kirkevold, Hall, & Østergaard, 2011; Marsh et al., 2004; Nuti et al., 2004). Unsurprisingly, lower quality of life in PD was associated with higher depression scores, and with longer disease duration (Grosset & Grosset, 2005). Mood was negatively influenced by unpredictable motor fluctuation, which fosters patients to a constant struggle to control what remains controllable in sticking to a daily routine and establishing fixed schedules (Haahr, Kirkevold, Hall, & Østergaard, 2010). Because of the progression of PD and associated dementia, most patients had given up work at an advanced stage of the disease (Hely et al., 2005).
Progression of PD has concrete implications on interpersonal relationships as well, with restrictions of social activities (Haahr et al., 2011; Haahr, Kirkevold, Hall, & Østergaard, 2013; Wressle, Engstrand, & Granérus, 2007) and communication difficulties (Caap-Ahlgren
& Lannerheim, 2002; Van der Bruggen & Widdershoven, 2004). Interpersonal issues also impact the patient’s partner, who additionally takes a caregiving role that can be very
demanding (Lyons, Stewart, Archbold, & Carter, 2009; Lyons, Stewart, Archbold, Carter, &
Perrin, 2004; Miller, Berrios, & Politynska, 1996). Partner’s perceived burden, which
9 increases along with PD progression, has been found to negatively predict the patient’s
capability of managing the disease (Edwards & Ruettiger, 2002). In accordance with these findings, a positive and direct relationship between psychosocial maladjustment and severity of PD has been statistically demonstrated (Navarta-Sánchez et al., 2016).
Thus, in a nutshell, patients at an advanced stage of PD face different kinds of problems.
Their dopaminergic medication is no longer capable of containing symptoms without
triggering adverse effects and, associated with this, their global clinical worsening negatively impacts various aspects of daily life such as self-image and interpersonal relations.
Deep brain stimulation
When disabling symptoms persist despite optimal medical treatment, or when these symptoms are directly caused by medication, high-frequency deep brain stimulation (DBS) may be proposed as an alternative treatment provided that no major contraindications coexist (e.g., advanced age, serious comorbidities) (Pollak, 2013). This surgical procedure refers to a stereotactic neurosurgical procedure during which electrodes are implanted into strategic deep nuclei of the brain—including the subthalamic nucleus (STN), theglobus pallidus pars interna (GPi), and the ventrointermediate (VIM)nucleus of the thalamus—to regulate motor
dysfunction. It was initiated in the late 1980s for tremor and the early 1990s for PD
(Miocinovic, Somayajula, Chitnis, & Vitek, 2013) and is usually undertaken 11 to 13 years after diagnosis (Deuschl et al., 2006; Follett et al., 2010; Okun et al., 2012; A. Williams et al., 2010). Magnetic resonance imaging is used to visualize the neuroanatomical target.
Neurosurgeons employ a specific software to construct a stereotactic target and
microelectrodes to find the most adequate track to reach this target. Implantation is usually undertaken under local anesthesia, which allows neurologists to test the patient’s clinical response to DBS during the procedure and define the best location. Microelectrodes are then replaced by leads that will remain permanently in the brain, fixed to the skull and powered by
10 a pulse generator inserted under the skin in the subclavicular area at the end of the surgical procedure or a few days later (Benabid, Chabardes, Mitrofanis, & Pollak, 2009).
As of today, over 150,000 patients have been treated with DBS worldwide (Lozano &
Lipsman, 2013). This number is expected to gradually increase because the surgical procedure has been clinically or experimentally applied to a variety of medical conditions such as
Tourette syndrome, treatment-resistant depression or obsessive-compulsive disorder (Cohen, 2012; Miocinovic et al., 2013). In comparison to lesioning approaches involving permanent damage to a part of the brain, DBS minimizes irreversible changes to brain structures, carries a relatively small risk of surgery-related complications, and can be adjusted to symptom progression (Larson, 2014).
In PD, DBS provides very large and positive effects (Cohen’s d > 1.20) on both
improvement of motor symptoms and reduction of dopaminergic medication intake, compared to patients receiving the best medical treatment (Perestelo-Pérez et al., 2014). Of peculiar interest for this thesis, DBS also provides beneficial effects (d .30) on various psychological and psychosocial variables, such as depression, mental health, and activities of daily living (Perestelo-Pérez et al., 2014). The STN and the GPi are most frequently chosen as
neuroanatomical targets for DBS in PD (PD-DBS). The role of the thalamus, the pallidum and the STN in motor regulation has long been demonstrated, and stereotactic lesioning during surgery has shown that high frequency stimulation of the VIM nucleus of the thalamus leads to decrease of rest tremor in PD (Benabid et al., 2000). High frequency stimulation of the STN and the GPi is followed by global improvement of PD symptoms, including rigidity, akinesia and levodopa-induced motor fluctuations (Obeso & Olanow, 2001). Patients with STN- and GPi-DBS show similar motor and psychosocial improvement (Boel et al., 2016;
Volkmann et al., 2009; Weaver et al., 2012). The target role regarding cognitive functions remains unclear, as some noticed that STN-DBS was associated with cognitive impairment
11 (Weaver et al., 2012) but others did not find differences between STN and GPi surgery (Boel et al., 2016).
Dissatisfaction following DBS. Despite undeniable motor improvement and general beneficial effects on psychosocial variables, PD-DBS has been associated with a range of problematic outcomes. First, psychosocial and mental variables seem to return to preoperative scores in the long run (Deuschl et al., 2006; Funkiewiez et al., 2004; Kaiser, Kryspin-Exner, Brücke, Volc, & Alesch, 2008), and this trend appears to be independent from the
neuroanatomical target (Volkmann et al., 2009; Weaver et al., 2012). Second, an important proportion of patients, that is 21% to 43 %, experienced no significant benefit from DBS in terms of quality of life even during the initial postoperative year (Daniels et al., 2011;
Smeding, Speelman, Huizenga, Schuurman, & Schmand, 2011). Third, most patients
undergoing DBS do not resume a professional activity, suggesting that motor improvement is independent from professional rehabilitation (Deli et al., 2015; Schüpbach et al., 2006).
More recently, researchers had started paying particular attention on the mental health consequences of PD-DBS, initially noticing that motor symptom improvement was not necessarily accompanied by improvement on other variables like cognition (Saint-Cyr, Trépanier, Kumar, Lozano, & Lang, 2000), mood (Berney et al., 2002) or quality of life (Houeto et al., 2002). The question of considering mental variables in selecting suitable candidates for surgery was debated (Houeto et al., 2002). Surgery was indeed initially suspected to trigger mental health problems after cases of hypomania (Krack et al., 2001;
Kulisevsky et al., 2002; Ulla et al., 2011), pathological gambling (Smeding et al., 2007) and depression (Bejjani et al., 1999; Tommasi et al., 2008) were observed immediately after stimulation activation.
In addition, investigators observed an increasing suicide rate in patients undergoing surgery for a variety of movement disorders including PD (Burkhard et al., 2004; Foncke,
12 Schuurman, & Speelman, 2006; Funkiewiez et al., 2004). Although more recent research has suggested that DBS per se does not induce suicidal behavior (Weintraub et al., 2013), cases of suicidal ideation, suicide attempts, or suicides have been reported in PD-DBS patients by numerous studies up to two years after surgery (Berney et al., 2002; Deuschl et al., 2006;
Fluchere et al., 2014; Gervais-Bernard et al., 2009; Houeto et al., 2002; Schüpbach et al., 2005, 2013; Strutt, Simpson, Jankovic, & York, 2012; Vesper, Haak, Ostertag, & Nikkhah, 2007; A. Williams et al., 2010; Witt et al., 2008; York et al., 2008). This shows that PD-DBS patients remain at risk of experiencing suicide-related issues during the postsurgical process.
Overall, these mood and behavior disturbances occurred mainly during the initial postoperative phase and were completely rectified after adjustment of DBS electrical parameters (including the stimulated neuroanatomical region with the correct selection of electrical contacts) or/and drug treatment (Volkmann, Daniels, & Witt, 2010). Similarly, hypomanic and behavioral symptoms gradually disappeared in the months following surgery (Herzog, Reiff, et al., 2003; Romito et al., 2002).
In light of the above, the question arises as to whether a difference should be made between mental health variables—globally preserved, even improved after surgery—and psychosocial variables, the latter seeming to affect a majority of patients around issues such as post-treatment expectations, acceptance of life with DBS, and interpersonal relationships (Houeto et al., 2006; Perozzo et al., 2001). Variables likely to play a significant role in the post-DBS living experience were further defined, and associated with possible changes in the patient’s self-identity, interpersonal and couple relationships (Agid et al., 2006; Schüpbach et al., 2006), a reflection on the unrealistic, preoperative expectations about treatment outcome endorsed by some patients (M. I. Hariz, 2014; Hasegawa, Samuel, Douiri, & Ashkan, 2014;
Joint & Aziz, 2014; Maier et al., 2013), and a focus on the psychological burden carried by significant others supporting PD patients (Haahr et al., 2013; C. J. Lewis, Maier, Horstkötter,
13 Eggers, et al., 2015). Progressively, the concept of social or psychosocial adjustment has emerged as a pivotal theme in the post-DBS rehabilitation of PD patients (Haahr et al., 2010;
M. Meyer et al., 2013). A recent study has provided empirical data supporting the beneficial effects of designing specific rehabilitation programs based on psychosocial adjustment (Flores Alves Dos Santos et al., 2017).
The paradox of patients experiencing a “medically successful DBS”—objectively assessed in measuring the pre/post-operative difference of motor functioning—but nevertheless a
“psychosocially unsuccessful DBS” characterized by dissatisfaction regarding the everyday life was pictured as a ‘burden of health’ by Burkhard and collaborators (2004). Despite the growing number of studies addressing post-operative psychosocial problems, no theoretical model has been used to account for this process. Keeping up with the pioneering work of Gilbert (2012), this work aims to fill the gap by applying the burden of normality (BoN) model to PD-DBS.
The burden of normality model
The BoN concept (Bladin, 1992; Wilson, Bladin, & Saling, 2001) stems from feedback analyses of patients who underwent anterotemporal lobectomy (ATL) for epilepsy in the Austin Hospital of Melbourne, Australia, in the beginning of the 1990s. At this time, it was observed that difficulties experienced by these patients during rehabilitation were of different kinds including family dynamics and individual behavior, and seemed independent from epileptic status, that is the number of remaining seizures following surgery (Bladin, 1992). A few years later, the publication of a series of studies empirically supported that the perceived treatment outcome—in this case, ATL—did not only depend on the reduction of seizures, but also on psychosocial variables such as preoperative expectations, postoperative affects, and attitudes towards the illness and rehabilitation (Bladin, Wilson, Saling, McIntosh, & O’Shea, 1999; Wilson, Saling, Kincade, & Bladin, 1998; Wilson, Saling, Lawrence, & Bladin, 1999).
14 In a subsequent stage, a model of post-operative psychosocial adjustment was formally
designed and labeled burden of normality (Wilson, Bladin, & Saling, 2004, 2001, 2007), because “adjustment primarily depends on the patient’s capacity to discard roles associated with chronic epilepsy and to learn to become well” (Wilson, Bladin, & Saling, 2001, p. 652).
Figure 3 The BoN model as summarized by Wilson et al. (2001)
15 As shown in Figure 3, the model was divided in three parts; first, the clinical manifestations of psychosocial maladjustment, which was designed as a “syndrome”; second, the
preoperative expectations on postoperative outcome, which was hypothesized to play a mediating role in the expression of psychosocial adjustment, and; third, three precursory conditions defined as necessary for the potential development of psychosocial maladjustment after treatment.
The syndrome. The model identifies four types of manifestations corresponding to the expression of psychosocial adjustment difficulties. These categories are hypothesized to be interrelated.
• Psychological manifestations are characterized by a sensation of grief for the loss of the disease, the formulation of increased expectations placed by patients on themselves or perceived from others, or feelings that opportunities have been missed and must now be taken up. The desire to prove one’s “normality” has also been attributed to this category, potentially leading to dramatic consequences.
• Behavioral manifestations are characterized by a tendency to increase or, on the contrary, avoid activities in physical, vocational or social areas, which can be associated with problems such as drug consumption or alcohol overconsumption, unsafe sex drive, or relinquishment to keep up with demands of posttreatment life.
• Affective manifestations are characterized by mood alterations such as anxiety, depression, euphoria or suicide-related behaviors.
• Sociological manifestations are characterized by challenges in the couple, family or social circle dynamics, such as redefinition of roles, or reformulation of life objectives.
Serious consequences of those manifestations were clinically observed. For instance, Bladin and colleagues (1999) reported cases of seizure-free patients who anew experienced
16 seizures after non-complying with medication. Similarly, an important proportion (21%) of patients undergoing ATL necessitated hospital readmission at some point during the course of the postoperative period within the context of affective (anxiety, depression, psychosis) or sociological (disruption of family dynamics, limited social network) manifestations of the BoN (Wilson, Kincade, Saling, & Bladin, 1999). Occurrences of suicide-related behaviors or suicides were also documented (Bladin, 1992), the latter being referred as the “ultimate paradox of treatment ‘cure’” (Wilson et al., 2004; p. 14).
Studies addressing the BoN in longitudinal designs allow us to infer on the trajectories of psychosocial manifestations over time. Overall, shortly after ATL for epilepsy, positive feelings defined as “joy of cure” and “euphoria” occurred along with a phenomenon of
increasing expectations for the future (Wilson et al., 2004; Wilson, Bladin, Saling, & Pattison, 2005a; Wilson, Wrench, McIntosh, Bladin, & Berkovic, 2010; Wilson, Bladin, & Saling, 2001; Wilson, Bladin, et al., 2007; Wilson, Frazer, Lawrence, & Bladin, 2007). Yet, others have identified a more ambivalent period associated with major increase of BoN symptoms, that is from 29% to 62% during the first three months following surgery, and noticed affective, behavioral and sociological manifestations—the latter including patients’ partners—within the six months following surgery (Wilson et al., 2005a; Wrench, Wilson, & Bladin, 2004). In the same vein, a study demonstrated that anxiety and poor social functioning during the preoperative period were associated with low quality of life after temporal lobe surgery for epilepsy (Kemp et al., 2016).
In the longer run, authors observed a trend toward symptom improvement, suggesting that the occurrence of BoN manifestations at some time of the postoperative recovery was
unsurprising or even necessary for subsequent global positive outcome. Indeed, early
postoperative anxiety seemed to be predictive of a variety of major future outcomes, as it was associated with mood impairment at 12 months but, if successfully treated, also with a
17 positive general development at the 24-month assessment (Wilson et al., 2005a). Similarly, a 12-month postoperative evaluation showed that experiencing adjustment issues was related to perception of identity change, yet also associated with higher quality of life (Wilson et al., 2010). However, BoN symptoms tended to increase over a 24-month follow-up period in epilepsy patients (Wilson et al., 2004; Wilson, Bladin, Saling, McIntosh, & Lawrence, 2001).
Thus, the BoN literature has highlighted heterogeneous responses of patients in terms of psychosocial adjustment after epilepsy surgery, which implies that various challenges appear at different periods of the rehabilitation. Postsurgical psychosocial adjustment does not seem to follow a linear trajectory, which may result in occurrence of new symptoms months after surgery.
Expectations. The model formally identifies the expectations of what life after treatment should be—hereinafter referred to as “expectations”—as playing a central role in the extent to which the posttreatment adjustment process is accompanied by BoN manifestations (Wilson, Bladin, & Saling, 2001). Expectations exerted a significant effect on perceived treatment success independently from the medical outcome—in this case, seizure occurrence following ATL (Wilson, Saling, et al., 1999). This finding suggests that adjustment already begins in the pretreatment phase (Wilson et al., 2004; Wilson, Bladin, et al., 2007; Wilson, Saling, et al., 1999). Concretely, patients who formulated expectations of practical improvements (e.g., seizure ablation, driving a car, finding a job) perceived surgery as more successful, experienced less seizure occurrences, and underwent less psychosocial difficulties than patients who emphasized expectations of psychosocial changes (e.g., increasing personal independence, improving family dynamics) (Wilson et al., 1998). More specifically, having positive and realistic expectations of posttreatment change should be predictive of a less problematic psychosocial adjustment, characterized with fewer BoN manifestations (Wilson et al., 2004; Wilson, Saling, et al., 1999). Endorsed by patients as well as significant others,
18 potentially dissimulated and formed in a context of negative core beliefs associated with the chronic illness, expectations unsurprisingly stand forward in the first proposal of a theoretical conceptualization of the BoN (Bladin et al., 1999; Wilson, Bladin, & Saling, 2001).
Although not conceptualized as such in the diagram illustrating the BoN (see Figure 3), another variable has been presented by Wilson and collaborators as playing a mediating function in the posttreatment manifestations of psychosocial maladjustment. This variable refers to the capability of discarding the roles associated with the limitations imposed by the disease before treatment (hereinafter referred to as “sick roles”), and adopting roles adapted to the posttreatment clinical condition. Such a capability to forgo sick roles has been
hypothesized to be the central variable upon which posttreatment outcome depends (Wilson, Bladin, & Saling, 2001). Empirical observations made in the context of ATL for epilepsy showed that 7% of siblings complained about patients maintaining sick roles (Bladin, 1992), whereas up to 31% of patients expressed those difficulties at some point during the year following surgery (Wilson et al., 2005a).
Precursory conditions. According to the theory, BoN manifestations can occur in patients meeting three precursory premises, specifically:
1. The presence of a chronic illness;
2. A sense of disablement, and;
3. The possibility to experience a cure leading to a dramatic improvement of disease- specific symptoms—e.g., disappearance of epileptic seizures (Wilson, Bladin, &
Saling, 2001).
This implies that a BoN might occur in medical conditions other than epilepsy treated with ATL if these three premises are fulfilled. In practice, a few studies have used the BoN collecting first-hand data in epilepsy with extratemporal resections (Wrench et al., 2004),
19 chronic narcolepsy-cataplexy with medication (Wilson, Frazer, et al., 2007), and to a lesser extent cardiac diseases treated with surgery (Genardini, Wilson, Lawrence, & Hare, 2008).
In line with the above, initial evidence was provided on the potential applicability of the BoN to diseases treated with DBS including PD. Gilbert (2012) and other authors (Bell, Maxwell, McAndrews, Sadikot, & Racine, 2011; Flores Alves Dos Santos et al., 2017; Péron, 2016) have indeed suggested that the difficulties experienced by DBS patients could be relevantly conceptualized in terms of psychosocial adjustment such as addressed by the BoN.
However, no empirical study assessing the applicability of the BoN framework to PD-DBS has been conducted yet.
Manifestations of psychosocial maladjustment
From an alternative standpoint, the BoN suggests that psychosocial adjustment is
organized around two types of variables: intrapersonal and interpersonal. This implies that the quality of psychosocial adjustment following PD-DBS depends on variables inherent to the patient him/herself (e.g., personality, mood, expectations) and on variables addressing interactions between the patient and his/her interpersonal environment (e.g., family and couple dynamics, professional reinsertion). In Figure 3, we can infer which BoN variables would rather be categorized as intrapersonal and which ones rather as interpersonal. For example, “psychological manifestations” are mostly intrapersonal because they deal with the patient’s inner world (e.g., “How can I feel comfortable with an electrical device in my body?”); in contrast, “sociological manifestations” are arguably interpersonal as they refer to the patient’s interaction with external individuals or situations. Other variables are less easy to categorize, for instance expectations that can be formulated by the patient him/herself but also by significant others.
Based on our clinical experience, we believe that the support of friends and family is pivotal in the patient’s rehabilitation. Notably, the support of the spouse/partner is of
20 importance because of the old-established caregiving role usually endorsed by the latter. In this regard, we expect that psychosocial adjustment to life with DBS would be influenced by changes in the couple dynamics during the period prior to and following surgery. In addition, we have also frequently observed in our clinical practice that patients had modified their way of seeing life throughout the surgical process. This may be imputable to various causes, but among them it is worth wondering whether DBS may alter their representations of PD and their personal relationship with it.
The following section brings to light two of these psychosocial variables, one
interpersonal and the other intrapersonal, which play a key role in the patient’s psychosocial adjustment after PD-DBS. These variables are couple satisfaction and illness representations.
Couple satisfaction. Satisfaction in the couple relationship has been defined as “one’s subjective global evaluation of one’s relationship” (Graham, Diebels, & Barnow, 2011).
While PD progresses to an advanced stage, dynamics of interpersonal relationships are challenged. Notably, this relates to patients’ partner and main caregiver, who is in most cases the same person (Schrag, Hovris, Morley, Quinn, & Jahanshahi, 2006). Life with advanced PD has been associated with the notion of partnership, in which solidarity and unity among the couple members are pivotal for positive relationship outcome. This requires a strong implication of the partner in understanding the patient’s disease and arranging their schedule to carry out adapted activities (Haahr et al., 2013). In this regard, it is relevant to consider the general experience of life with advanced PD from the prism of the dyad.
Research has demonstrated that patients’ life experience is significantly associated with that of their partner. Patients’ identity is increasingly challenged as PD progresses, in terms of individual variables, such as body image and self-esteem, but also regarding interpersonal variables, specifically in the management of social contacts. Patients indeed become more dependent on others than they used to be, which may result in guilt feelings and may reduce
21 the social network to significant others or to those with similar problems (Haahr et al., 2011;
Van der Bruggen & Widdershoven, 2004). Direct implications on couple relationship with regards to social life are eloquently illustrated through a patient’s testimony proposed by Haahr and collaborators (2011): ‘It hurts that it always affects my wife, when she must go on her own, and really would have liked me to come with her… sometimes I have felt it wasn’t good, but went along anyway, and sometimes we have had to go home again within an hour’
(p. 413). By the same token, patients experience discomfort toward others’ gaze, which fosters social isolation and feelings of shame (Bramley & Eatough, 2005; Caap-Ahlgren &
Lannerheim, 2002; Haahr et al., 2011; Wressle et al., 2007). A woman with advanced PD explains that she “[feels] especially watched” by other people, with the fear that “people around [her] think [she is] incompetent, think [she is] an idiot”. Such a situation may concretely impact patients and their families, as this woman was thinking of moving to another area to avoid these negative reactions (Caap-Ahlgren & Lannerheim, 2002, p. 90).
Communication is also impaired by physical symptoms, notably elocution difficulties and loss of affect in speech, and this contributes to social alienation as well (Van der Bruggen &
Widdershoven, 2004). In addition, PD has a negative impact on sexuality with dissatisfaction and avoidance of sexual intercourses (Buhmann et al., 2017).
Similarly, the caregiver burden increases for all variables measured such as general worry and feelings of lack of resources (Carter et al., 1998). Daily implication in the caregiver role seems to be particularly demanding as partner caregivers were more at risk of suffering from stress and anxiety than caregivers with another status such as sons or daughters (Aarsland, Larsen, Karlsen, Lim, & Tandberg, 1999). Caregivers reported high levels of psychological and physical difficulties (Aarsland et al., 1999; Miller et al., 1996; Schrag et al., 2006), with loss of usual roles in the couple relationship and decreased socialization (Wressle et al., 2007).
Moreover, caregivers may not always be willing of expressing their negative feelings in order
22 to protect their ill partner, as admitted in the following testimony: “I often feel I have to be the strong one. And often he says to our friends that I am so strong. But deep down I am not”
(Haahr et al., 2013, p. 342). Thus, the dyad is at risk of being caught in a vicious circle, in which the caregiver perception of an increasing burden is associated with decreasing efficiency in the patients’ PD management (Edwards & Ruettiger, 2002), while patient’s depression becomes the best predictor of caregiver burden (Miller et al., 1996).
Although protective factors have been identified—specifically, positive relationship and communication within the couple, high optimism and low pessimism for caregivers at early stage of the disease (Lyons et al., 2009, 2004)—, difficulties in the couple relationship globally appear positively correlated to PD progression. From this standpoint, it may be expected that symptom reduction brought in by medically successful DBS surgery would result in an improvement of the couple relationship. However, research on this matter provides equivocal conclusions. On the one hand, some authors have underscored a positive experience in the relationship after PD-DBS when members of the couple remained
supportive to each other (Haahr et al., 2010, 2013). Besides, a study showed that satisfaction in the relationship was sustained in 81% to 86% of patients, respectively 70% to 77% of partners, three years after surgery (Boel et al., 2016). However, on the other hand, other researchers reported more nuanced outcomes. Two publications have notably drawn the attention of the scientific community in pointing out a range of long-lasting problems, including problems within the couple relationship, which occurred in the post-DBS
rehabilitation. Testimonies of patients rejecting and being rejected by their spouses two years after surgery were qualitatively documented (Agid et al., 2006), while quantitative data from the similar cohort showed that 58% of spouses were disappointed by the DBS outcome, 33%
became clinically depressed, and that successful surgery was rarely accompanied by
improvement in dyads experiencing crisis preoperatively (Schüpbach et al., 2006). A spouse
23 of one of our HUG patients took a critical look at the post-DBS life, pointing out that “pace of life is still different” between her husband and the rest of the family, with strong feelings that
“nothing is never taken for granted” and that she is “constantly seeking a balance” in her relationship more than one year postoperatively (interview conducted in Geneva on March 18, 2018). Overall, these data are in line with previous ones pointing out role loss and feelings of disappointment in caregivers within six months after PD-DBS (Perozzo et al., 2001). These data also suggest that difficulties in the couple relationship is not only related to the post-DBS adjustment process, assumed to last for about one year (Haahr et al., 2010), and whose
treatment-related requirements (e.g., finding the adequate stimulation parameters) have been directly associated with strains in couples (Haahr et al., 2013; Perozzo et al., 2001).
Thus, the heterogeneity of the above data prevents drawing definite conclusions on the post-DBS outcome in terms of couple satisfaction. There is a lack of research addressing the psychosocial experience of the couple relationship before and after PD-DBS, and variables of the BoN such as expectations and changing roles have not been explored from a dyadic perspective. This requires further research targeting the patient’s and partner’s individual experience, as well as the adjustment process of the dyad.
Illness representations. As the BoN suggests that psychological variables play a role in the psychosocial adjustment process, it is worth wondering whether patients’ representations of PD remain stable or, on the contrary, are subject to change throughout the DBS process.
We will consider illness representations from the “common sense model” (CSM) of Howard Leventhal and his colleagues (Leventhal et al., 2012; Leventhal, Meyer, & Nerenz, 1980).
This theoretical model has been progressively built to explain how individuals deal with a change in their perceived health. The CSM depicts a three-step dynamic process positing that;
24
• First, internal or external stimuli (e.g., appearance of clinical symptoms) generate cognitive and emotional representations of what is associated with a potential danger (e.g., an illness);
• Second, these representations are addressed by coping strategies;
• Third, the efficiency of the latter coping strategies to deal with the
symptoms/illness are appraised and possibly modified to better adapt the situation.
Thus, this dynamic process potentially leads to the formation of new representations, coping strategies and appraisals (Leventhal et al., 1997).
The CSM in PD. To our knowledge, four studies investigated illness representations from
the perspective of the CSM in non-operated PD patients (Evans & Norman, 2009; Hurt et al., 2014; Julien, Rimes, & Brown, 2016; Simpson, Lekwuwa, & Crawford, 2013). Overall, these studies found that strong identity (i.e., cognitive identification of symptoms associated with the entity commonly represented as “Parkinson’s disease”), chronic timeline (i.e.,
representation of PD as a chronic disease) and serious consequences of PD (i.e.,
representation that PD has serious consequences on daily living) are associated with low well- being. However, no study has addressed illness representations in the context of PD-DBS.
In research conducted on the consequences of ATL for epilepsy, Wilson and colleagues (2001) considered that postoperative psychosocial adjustment was influenced by the core beliefs associated with chronic epilepsy. The presence of negative core beliefs were indeed observed in various chronic conditions (Mizara, Papadopoulos, & McBride, 2012; Tedman, Thornton, & Baker, 1995). Despite the absence of research using the CSM in patients undergoing DBS for PD, several elements suggest that such an approach, which underscores the role of lay beliefs in the illness experience, may be of interest to illuminate their global adjustment process. One may hypothesize that medically successful DBS, in reducing motor symptoms of PD, will lead to less severe representations of the identity and consequences
25 components of the illness and, subsequently, have a positive impact on adjustment outcomes.
From this perspective, patients experiencing psychosocial maladjustment after DBS would fail to change these representations and sustain strong identity and serious consequences.
One may also assume that the control/cure dimension of illness representation (i.e., the personal beliefs about the controllability and the curability of the illness) would be influenced by DBS surgery: The patients’ desire to personally control the course of the disease in the pre- DBS advanced PD (Haahr et al., 2011) switches to feelings that this control has been taken by external persons (i.e., neurologists in charge of adjusting stimulation parameters) (Haahr et al., 2010). Similarly, patients having representations of PD as a cyclical illness tend to experience psychological distress and poorer quality of life (Evans & Norman, 2009; Hurt et al., 2014);
because DBS improves motor fluctuations (Benabid et al., 2000), it could be hypothesized that PD would be less viewed as cyclical after surgery. In contrast, we would expect no change between pre- and post-DBS assessments in the cause component of illness
representations (i.e., patients’ representations of the causes of their illness), as DBS is not likely to modify the way patients understand reasons for PD development.
In line with the above, the disruptive DBS experience, illustrated by these hypotheses on possible changes in illness representations, may conduct patients to adjust their ways of coping with their clinical condition. Few studies have longitudinally addressed coping strategies before and after PD-DBS and none used the CSM. In addition, these studies have yielded contradictory findings. While some found that patients use more frequently
instrumental coping strategies (e.g., looking for information or for efficient treatment) before than after surgery (Flores Alves Dos Santos et al., 2017; Montel & Bungener, 2008, 2009), others noted that coping strategies were not used differently over this period (Soulas, Sultan, Gurruchaga, Palfi, & Fénelon, 2011). Changes in coping strategies have been associated with patients’ situation regarding their illness. Those about to undergo surgery or who possibly
26 could be treated by DBS in the future seek out further information on this procedure, hence a more frequent use of instrumental strategies. In contrast, patients already operated may be concerned by new life issues and, accordingly, adjust their ways of coping; yet, they keep using more instrumental strategies that those not selected for DBS, who used predominantly emotional coping strategies (e.g., avoidance, emotional preoccupation) (Montel & Bungener, 2008, 2009). Nevertheless, those who after DBS kept using problem-focused coping—that is, strategies likely to be, at least partly, instrumental—had lower quality of life (Soulas et al., 2011). Based on these findings, one might suppose that psychosocial maladjustment
experienced after PD-DBS would be somehow associated with a tendency to stick to problem- focused/instrumental coping strategies.
Thus, the CSM constitutes a theoretical framework allowing hypotheses about how the articulation between illness representations and coping strategies may lead to positive, respectively negative, perceived outcome—measured in our context in terms of BoN
symptoms. In this regard, patients displaying flexibility in illness representations and coping strategies would be potentially subject to better psychosocial adjustment as they can more easily adapt to the drastic direct and indirect changes brought in by DBS surgery.
27 Aims of the thesis
The present thesis aims at expanding the work of Gilbert (2012) and showing that the BoN is useful to account for the psychosocial adjustment process of patients undergoing DBS for PD. It follows a top-down approach corresponding in the redaction of five scientific articles designed ultimately to be submitted to journals proposing a peer review publication process (Figure 4). The initial part of the thesis addresses the application of the BoN to PD-DBS from an overall viewpoint including all elements of the model (Studies 1 and 2). The second part of the thesis focuses on specific elements that could be classified as BoN manifestations of psychosocial maladjustment in case of dysfunction. These elements are couple relationship (Studies 3 and 4) and illness representations (Study 5), potentially belonging to the
“sociological”, respectively “psychological” manifestations of the BoN applied to PD. In selecting these two elements among others (e.g., depression, anxiety, identity, vocational rehabilitation), the current thesis proposes a two-track approach; first, contributing to the further understand an already studied topic, namely couple relationship after DBS and; second, exploring a theme not yet studied – that is, illness representations before and after DBS from the CSM perspective – but arguably of interest to better comprehend the psychosocial experience of these patients.
28 Figure 4 Organization of the thesis studies
Studies presented in the thesis
The first study attempts to find correspondences between the different elements of the BoN (i.e., precursory conditions, mediating variables, syndrome manifestations) and the clinical observations of the pre- and post-DBS experience of PD patients published in the literature. Because no research presenting original data has utilized the BoN in the context of PD-DBS, this study is not, strictly speaking, a literature review but rather a literature
investigation. We hypothesize that the correspondences between the PD-DBS experience and the theoretical BoN will be solid enough to allow us inferring that the BoN – provided that it
29 is adapted to specificities inherent to PD-DBS – is a valid framework to comprehend the psychosocial process accompanying patients throughout the whole DBS rehabilitation.
Following the latter hypothesis, the second study aims to concretely use the BoN to explore the psychosocial adjustment of PD patients implanted with DBS. Designed under the form of a pilot study including about 20 patients, this article is built upon retrospective,
qualitative data analysis obtained with the adaptation to PD-DBS of the Austin CEP Interview, a semi-structured instrument initially developed by the Melbourne team (Bladin, 1992;
Wilson, Saling, et al., 1999). Thus, this study is the first using the BoN to procure original data on a potential application of the BoN to PD-DBS.
In line with the top-down approach of this thesis, the third and fourth studies address a specific issue listed in the BoN syndrome under the “sociological manifestations” category, namely difficulties in the couple relationship, in this case in the context of PD-DBS. The third article consists of a French validation of the Marital Satisfaction Scale (MSS, Roach, Frazier,
& Bowden, 1981), a self-administered questionnaire assessing satisfaction in the couple relationship. Contrary to other instruments (e.g., DAS), the MSS posits that couple
satisfaction is a unidimentional, specific construct, which is de facto different from couple adjustment. Considering the very heterogeneous life situation between PD patients and their non-PD partners, we estimated that it was more appropriate to investigate a single dimension of couple adjustment – that is, satisfaction – and limit the interference of potentially
confounding variables. The MSS appeared in this regard relevant to this end. This article has been accepted for publication in May, 2017 in the European Review of Applied Psychology and entitled “French validation of a brief version of the Marital Satisfaction Scale”. It is the only one among the five articles to be written in the French language.
The fourth study investigates the trajectories of couple satisfaction, a sociological manifestation of the BoN, from the patient’s point of view in a longitudinal, post-DBS 18-
30 month follow-up. This study follows several objectives. First, it aims at providing further data on a topic that has been poorly studied to date, and whose findings, as mentioned above, have led to mixed outcomes. Second, it is experimentally designed so that patients are assessed four times from a few weeks before until 18 months after surgery; this allows a fine bservation of the immediate post-DBS period, which has been considered as pivotal in the psychosocial adjustment process (Haahr et al., 2010).
Finally, the fifth study addresses illness representations, a psychological manifestation of the BoN, as conceptualized by the CSM in patients selected for DBS surgery. This study is currently in progress.
31 Empirical section
The first study has been accepted by the journal Neuropsychology on August 31st, 2018, and is referenced as follows:
Baertschi, M., Flores Alves Dos Santos, J., Burkhard, P., Weber, K., Canuto, A., & Favez, N.
(2018). The burden of normality as a model of psychosocial adjustment after deep brain stimulation for Parkinson’s disease: A systematic investigation. Neuropsychology. Manuscript accepted fur publication on August 31st, 2018.
The second study has been submitted to the journal Neuropsychology on September 14, 2018, and the submission process is in progress. It is referenced as follows:
Baertschi, M., Favez, N., Radomska, M., Herrmann, F., Burkhard, P., Canuto, A., … Flores Alves Dos Santos, J. (n.d.). Burden of normality and deep brain stimulation for Parkinson’s disease. Manuscript submitted.
The third study has been accepted for publication by the Revue européenne de
Psychologie appliquée / European Review of Applied Psychology on May 18th, 2017, and is referenced as follows:
Baertschi, M., Flores Alves Dos Santos, J., Tissot, H., Canuto, A., Favez, N., & Weber, K.
(2017). Validation française d’une version brève de l’Échelle de satisfaction maritale. Revue Europeenne de Psychologie Appliquee, 67(4), 207–212.
http://doi.org/10.1016/j.erap.2017.05.002
The fourth study has been submitted to the Journal of Clinical Psychology in Medical Settings on September 13, 2018, and the submission process is in progress. It is referenced as follows:
32 Baertschi, M., Favez, N., Flores Alves Dos Santos, J., Radomska, M., Herrmann, F., Burkhard, P., … Weber, K. (n.d.). The impact of deep brain stimulation for Parkinson’s disease on
couple satisfaction: An 18-month longitudinal study. Manuscript submitted.
The fifth study is currently in progress and will be referred as follows:
Baertschi, M., Favez, N., Flores Alves Dos Santos, J., Radomska, M., Herrmann, F., Burkhard, P., … Ghisletta, P. (n.d.). The common-sense model of illness representations in patients treated with deep brain stimulation for Parkinson’s disease. Manuscript to be submitted.
