Caregiver burden and caregiver appraisal of psychiatric symptoms are not modulated by subthalamic deep brain stimulation for Parkinson's disease

Risk factors and intervention of caregiver burden in Parkinson's disease: a systematic review and meta-analysis

PURPOSE

This study summarized characteristics and risk factors of caregiver burden in PD patients and used meta-analysis to verify the effectiveness of the intervention on caregiver burden.

METHODS

Systematic review and meta-analysis were conducted.

RESULTS

Forty-nine articles that involved 5387 caregivers of patients with PD were included in this study. Results of systematic review indicated that Zarit burden Inventory (ZBI) was the most used scale to measure the caregiver burden. All scales revealed caregivers of PD patients had mild to moderate caregiver burden. For the PD patients with longer disease duration, severer disease severity, more negative emotion and cognition impairment, their caregivers intended to have higher caregiver burden. The caregiver with negative emotion and who spent more time on caregiving indicated higher caregiver burden than the others. The caregiver burden was not improved after deep brain stimulation (DBS). Meta-analysis showed that cognitive behavior therapy and palliative care had no significant effect to reduce caregiver burden in PD patients' caregiver.

CONCLUSION

Caregivers of PD patients experienced mild to moderate caregiver burden. Demographic factor, diseased-related factor and negative emotional factor were the risk factors of caregiver burden. Health education and care support for long-term management after DBS surgery should be provided for patients and caregivers to decrease caregiver burden.

Caregivers' burden and deep brain stimulation for Parkinson disease: A systematic review of qualitative studies

BACKGROUND AND PURPOSE

The impact of subthalamic nucleus deep brain stimulation (STN-DBS) on caregivers' burden is understudied. We perform a systematic review and meta-synthesis aggregating qualitative studies involving partners of people with Parkinson disease (PwP) to explore their experiences and unmet needs.

METHODS

A systematic review for retrieving qualitative studies included six databases: MEDLINE, Embase, CINAHL, Cochrane, PsycInfo, and Scopus. Inclusion criteria were as follows: (i) studies on the experience of caregivers of PwP in the context of STN-DBS, (ii) English peer-reviewed articles, and (iii) qualitative or mixed methods studies reporting caregivers' quotations. After the appraisal of included studies, we performed meta-synthesis of qualitative findings. Descriptive themes and conceptual elements related to PwP partners' experiences and unmet needs were generated.

RESULTS

A total of 1108 articles were screened, and nine articles were included. Three categories were identified: (i) dealing with Parkinson disease (PD) every day (the starting situation characterized by the impact of PD on ordinary life; the limitations to partners' socialization; partners' efforts in stepping aside for love and care activities), (ii) facing life changes with STN-DBS (the feeling of being unprepared for changes; the fear and concern due to loved ones' behavioral changes; struggling to find an explanation for those changes), and (iii) rebuilding the role of caregiver and partner after STN-DBS.

CONCLUSIONS

This meta-synthesis elucidates concerns, challenges, and unmet needs of partners of PwP who underwent STN-DBS. It is important to provide them with information, education, and adequate support to face these challenges. Professionals need to involve partners in the care and decision process, because STN-DBS-related outcomes do not depend solely on the well-being of PwP but also on the well-being of individuals surrounding them.

Caregiver Burden in Parkinson Disease: A Scoping Review of the Literature from 2017-2022

Caregiver burden is a term that refers to the adverse effect of caregiving on the physical, emotional, social, spiritual, and financial well-being of the caregiver. Caregiver burden is associated with providing care to an individual with a chronic illness or disability, and the unique symptoms of Parkinson disease (PD) can amplify a patient's needs and reliance on others, leading to adverse outcomes for patients and their caregivers. In this scoping review of the literature from January 2017 through April 2022 that included 114 studies, we provide an updated, evidence-based summary of patient and caregiver-related factors that contribute to caregiver burden in PD. We also describe the impact of caregiver stress and burden on caregivers based on qualitative research studies and review recent interventions to mitigate burden. By providing clinical updates for practitioners, this review is designed to improve recognition of caregiver burden in the post-pandemic era and foster the development of targeted interventions to reduce caregiver burden in PD.

Caregiver Burden and Quality of Life of Caregivers for Patients with Parkinson's Disease Treated with Deep Brain Stimulation

Objective

This study aimed to identify caregiver burden (CB) and contributing factors to CB for Parkinson's disease (PD) patients under Subthalamic Nucleus Deep Brain Stimulation (STN-DBS) treatment, and investigation the factors, affecting the caregivers' quality of life (QoL).

Methods

Twenty-four PD patients under STN-DBS treatment and their caregivers participated in this study. Unified Parkinson's Disease Rating Scale (UPDRS) was applied for the clinical assessment of the patients. Beck Depression Inventory-II (BDI), Hospital Anxiety and Depression Scale (HADS), and Minnesota Impulse Control Disorders Interview (MIDI) were used to screen for neuropsychiatric symptoms of the patients. CB was evaluated with the Caregivers Burden Inventory (CBI) and the Burden Scale for Family Caregivers (BSFC-s). The health-related QoL of caregivers was assessed with the Short Form Survey-36 (SF-36).

Results

Mean total CBI and BSFC-s scores of caregivers were 32.53 ± 19.71 and 11.66 ± 8.86, respectively. Nineteen caregivers defined moderate or severe caregiver burden according to BSFC-s. Both CBI and BSFC-s scores were significantly associated with UPDRS-part-1 scores, but not with the age and gender of both the patients and their caregivers, disease duration, PDQ39, BDI, HADS, LARS scores, and scores of patients for other UPDRS parts. The presence of impulse control behaviors (ICBs) significantly increased the total CBI score and total BSFC-s (P < 0.01). The caregivers' total and all domain scores of SF-36 were significantly affected by higher CBI and BSFC-s scores.

Conclusions

The CB of the patients under STN-DBS treatment was severe. Non-motor symptoms, particularly impulsivity, significantly increased CB and worsened the caregivers' mental and physical health.

Neuropalliative care for the neurosurgeon: a primer

Many neurosurgical conditions are incurable, leading to disability or severe symptoms, poor quality of life, and distress for patients and families. The field of neuropalliative care (NPC) addresses the palliative care (PC) needs of individuals living with neurological conditions. Neurosurgeons play an important role within multidisciplinary NPC teams because of their understanding of the natural history of and treatment strategies for neurosurgical conditions, longitudinal patient-physician relationships, and responsibility for neurosurgical emergencies. Moreover, patients with neurosurgical conditions have unique PC needs given the trajectories of neurosurgical diseases, the realities of prognostication, psychosocial factors, communication strategies, and human behavior. PC improves outcomes among neurosurgical patients. Despite the importance of NPC, neurosurgeons often lack formal training in PC skills, which include identifying patients who require PC, assessing a patient's understanding and preferences regarding illness, educating patients, building trust, managing symptoms, addressing family and caregiver needs, discussing end-of-life care, and recognizing when to refer patients to specialists. The future of NPC involves increasing awareness of the approach's importance, delineating priorities for neurosurgeons with regard to NPC, increasing emphasis on PC skills during training and practice, expanding research efforts, and adjusting reimbursement structures to incentivize the provision of NPC by neurosurgeons.

Patient-Related Factors Influencing Caregiver Burden in Parkinson’s Disease Patients: Comparison of Effects Before and After Deep Brain Stimulation

Background:

Caregivers of Parkinson’s disease (PD) patients provide important support during the pre- and postoperative phase of deep brain stimulation (DBS). High levels of caregiver burden have been reported after DBS. However, a comparison between preoperative and postoperative burden and associated factors has been insufficiently studied.

Objective:

To investigate the influence of DBS on caregiver burden, and to identify the differential impact of patient-related factors on caregiver burden before and after DBS.

Methods:

Consecutive patients referred for DBS eligibility screening or during one-year follow-up assessments were included. Caregiver burden was measured with the short Zarit Burden Interview (ZBI-12). Inverse Probability Weighting (IPW) was used to compare caregiver burden between preoperative and postoperative assessments.

Results:

We included 47 patients (24 screening, 23 follow-up) (median age 65 years, 29.4% female sex). DBS did not impact caregiver burden (screening: median ZBI-12 9.5 (IQR 3.25, 16.75); follow-up median ZBI-12 6 (IQR 4, 14); IPW-coefficient 0.57 (95% CI –2.75, 3.89)). Worse caregiver burden during DBS screening was associated with worse patient-related scores on depressive symptoms, anxiety, QoL, and impulsiveness. Worse scores on depressive symptoms, anxiety, apathy, postural-instability-gait-disorder, and QoL were associated with worse caregiver burden at one-year follow-up.

Conclusion:

DBS appears not associated with changes in caregiver burden. Various symptoms are valued differently between screening and follow-up assessments in terms of caregiver burden. Early recognition of caregivers “at risk” may improve guidance of patient-caregiver dyads throughout the DBS process.

Caregiver Burden in Partners of Parkinsonian Patients with Deep Brain Stimulation

In Parkinson’s disease (PD) patients, the progressive nature of the disease and the variability of disabling motor and non-motor symptoms contribute to the growing caregiver burden of PD partners and conflicts in their relationships. Deep brain stimulation (DBS) improves PD symptoms and patients’ quality of life but necessitates an intensified therapy optimization after DBS surgery. This review illuminates caregiver burden in the context of DBS, framing both pre- and postoperative aspects. We aim to provide an overview of perioperative factors influencing caregiver burden and wish to stimulate further recognition of caregiver burden of PD patients with DBS.

A Pilot Trial of Cognitive Behavioral Therapy for Caregivers After Deep Brain Stimulation for Parkinson's Disease

Subthalamic deep brain stimulation for Parkinson's disease may not ameliorate burden among caregivers. An 8-session, manualized program of cognitive-behavioral therapy (CBT) was delivered to a pilot sample of 10 caregivers (6 females, mean age: 60, age range: 34-79). Primary outcome measures were caregiver burden (Zarit Burden Interview) and caregiver quality of life (Parkinson's Disease Questionnaire-Carer). Secondary outcome measures comprised ratings of depression and anxiety in the caregiver, in addition to relationship quality. Caregiver burden (t = 2.91 P = .017) and caregiver anxiety (t = 2.82 P = .020) symptoms were significantly reduced at completion of the program, and these benefits were maintained 3 months later. Caregiver quality of life had significantly improved by the end of the intervention (t = 3.02 P = .015), but this effect was not sustained after 3 months. The longitudinal influence of participation in the program on caregiver burden was confirmed in a linear, mixed-effects model, χ² (3) = 15.1, P = .0017). The intervention was well received by participants, and qualitative feedback was obtained. These results indicate that caregiver burden is modifiable in this cohort with a short course of CBT, that benefits are maintained after termination of the program, and that psychological treatment is acceptable to participants. Larger, controlled trials are justified.

Bringing Advanced Therapies for Parkinson's Disease to the Clinic: An Analysis of Ethical Issues

Advanced therapies for Parkinson’s disease (PD) constitute a broad range of treatments, each presenting specific ethical challenges. Some of these therapies are established and in clinical use, like device-aided therapies, and others, based on advanced therapeutic medicinal products (ATMPs), are still in early stage of clinical trials. This paper focuses on some common ethical issues arising in these two categories of advanced therapies, especially challenges arising when advanced therapies are proposed to PD patients in the form of advanced care, under a clinical trial, or, in case of ATMPs, under the “hospital exemption” rule. The ethical issues covered here relate mainly to ensuring informed consent in these different contexts, to the stakeholder role of patient’s non-professional caretakers, such as family, and to patient safety in treatments under “hospital exemption”. To illustrate the points discussed in connection with “hospital exemption” rule, the example of the EU has been chosen. This paper does not claim completeness of ethical issues raised by bringing advanced therapies for PD to the clinic, but rather presents examples of ethical challenges in this context.

Intrajejunal Infusion of Levodopa/Carbidopa for Advanced Parkinson's Disease: A Systematic Review

Advanced Parkinson's disease is inconsistently defined, and evidence is lacking in relation to device‐aided therapies. To update existing reviews of intrajejunal infusion of levodopa/carbidopa (LCIG), we performed a literature search for relevant articles (to November 3, 2020) using PubMed supplemented by hand searching. Retrieved articles were categorized by relevance to identified research questions, including motor complications and symptoms; nonmotor symptoms; functioning, quality of life, and caregiver burden; optimal timing of treatment initiation and administration duration; discontinuation; and complications. Most eligible studies (n = 56) were open‐label, observational studies including relatively small patient numbers. LCIG consistently reduces OFF time and increased ON time without troublesome dyskinesia with varying effects regarding ON time with troublesome dyskinesia and the possibility of diphasic dyskinesia. More recent evidence provides some increased support for the benefits of LCIG in relation to nonmotor symptoms, quality of life, activities of daily living, and reduced caregiver burden. Patient age does not appear to significantly impact the effectiveness of LCIG. Discontinuation rates with LCIG (~17%–26%) commonly relate to device‐related issues, although the ability to easily discontinue LCIG may represent a potential benefit. LCIG may be a favorable option for patients with advanced Parkinson's disease who show predominant nonmotor symptoms and vulnerability to complications of other advanced therapy modalities. Larger, well‐controlled studies, including precise investigation of cost effectiveness, would further assist treatment selection. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

One Year Trajectory of Caregiver Burden in Parkinson's Disease and Analysis of Gender-Specific Aspects

Parkinson's disease (PD) is a slowly progressive neurodegenerative movement disorder that leads to impairments in activities of daily living. In addition to reducing patients' quality of life, this disease also affects caregivers' well-being. Until recently, caregiver burden was mainly assessed by generic questionnaires, which do not take the characteristics of the chronic disease into consideration. In the case of PD, this issue has been addressed by the introduction of the "Parkinson's disease caregiver burden" questionnaire (PDCB). Data on longitudinal trajectories of caregiver burden are still missing in the literature. In this study, we assessed the one-year trajectory of caregiver burden by the PDCB as a disease-specific questionnaire. Further, gender-specific aspects of caregiver burden were analyzed by applying a caregiver task questionnaire. PDCB total score (n = 84 patients and caregivers) did not significantly change from baseline (30.4) to one year at follow-up (31.5). No significant difference was detected between female and male caregivers in global burden and-specific caregiver tasks. Our data showed only a mild increase of caregiver burden in the timeframe of one year. Gender-specific differences do not seem to impact-specific caregiver tasks in the presented study population.

Apathy Induced by Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease: A Meta-Analysis

Apathy, the loss of motivation, is a common problem in Parkinson's disease (PD) and often observed following deep brain stimulation (DBS) of the subthalamic nucleus (STN). The aim of this meta-analysis was to determine the occurrence of apathy following STN DBS in literature. Relevant articles were searched in PubMed/Medline, SCOPUS, EMBASE, and Web of Sciences electronic databases. Studies were included if they reported apathy scores pre- and post-DBS or the cross-sectional difference between PD patients receiving STN DBS and patients receiving medication only. Thirty-three articles were included in the meta-analyses from 6,658 screened articles by two authors independently. A total of 1,286 patients were included with a mean age (±standard deviation [SD]) of 58.4 ± 8.5 years and a disease duration of 11.0 ± 5.8 years. The apathy score measured by means of the Apathy Evaluation Scale (AES), Starkstein Apathy Scale (SAS), and the Lille Apathy Rating Scale (LARS) was significantly higher after DBS than pre-operatively (g = 0.34, 95% confidence interval [CI] = 0.19-0.48, P < 0.001). An equal, significant difference in severity of apathy was found between STN DBS and medication only (g = 0.36, 95% CI = 0.03-0.65; P = 0.004). Statistical heterogeneity was moderately high, but the effects stood strong after multiple analyses and were independent of tapering off dopaminergic medication. The findings of this meta-analysis indicate that apathy is increased after STN DBS compared to the pre-operative state and to medication only (systematic review registration number: PROSPERO CRD42019133932). © 2020 Universiteit van Amsterdam. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Interdisciplinary Research in Alzheimer's Disease and the Roles International Societies Can Play

An ever-increasing ageing population has elevated Alzheimer's disease to be one of the biggest challenges in modern medicine. Alzheimer's disease is highly complex, and we are still no closer to understanding the causes, let alone an effective treatment. The lack of good experimental models and lack of critical understanding has led to high failure rates of clinical trials with high associated costs, as well as difficulties in implementing treatments. The multifaceted nature of this disease highlights the need for an interdisciplinary approach to address these concerns. In this essay, we suggest how collaborative work can be useful in addressing some of the above issues. We then propose that international organisations and publishers need to support interdisciplinary research by creating platforms, lobbying funders, and pushing for interdisciplinary publications. We further highlight some of the issues involved in implementing these suggestions and argue that willpower of the research community, together with a re-evaluation of evaluation metrics and incentive systems, are needed in order to foster interdisciplinary research. Overall, we emphasise the need for interdisciplinary research in Alzheimer's disease and suggest that international societies should play a huge role in this endeavour.

The structural connectivity of subthalamic deep brain stimulation correlates with impulsivity in Parkinson's disease

Subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease treats motor symptoms and improves quality of life, but can be complicated by adverse neuropsychiatric side-effects, including impulsivity. Several clinically important questions remain unclear: can 'at-risk' patients be identified prior to DBS; do neuropsychiatric symptoms relate to the distribution of the stimulation field; and which brain networks are responsible for the evolution of these symptoms? Using a comprehensive neuropsychiatric battery and a virtual casino to assess impulsive behaviour in a naturalistic fashion, 55 patients with Parkinson's disease (19 females, mean age 62, mean Hoehn and Yahr stage 2.6) were assessed prior to STN-DBS and 3 months postoperatively. Reward evaluation and response inhibition networks were reconstructed with probabilistic tractography using the participant-specific subthalamic volume of activated tissue as a seed. We found that greater connectivity of the stimulation site with these frontostriatal networks was related to greater postoperative impulsiveness and disinhibition as assessed by the neuropsychiatric instruments. Larger bet sizes in the virtual casino postoperatively were associated with greater connectivity of the stimulation site with right and left orbitofrontal cortex, right ventromedial prefrontal cortex and left ventral striatum. For all assessments, the baseline connectivity of reward evaluation and response inhibition networks prior to STN-DBS was not associated with postoperative impulsivity; rather, these relationships were only observed when the stimulation field was incorporated. This suggests that the site and distribution of stimulation is a more important determinant of postoperative neuropsychiatric outcomes than preoperative brain structure and that stimulation acts to mediate impulsivity through differential recruitment of frontostriatal networks. Notably, a distinction could be made amongst participants with clinically-significant, harmful changes in mood and behaviour attributable to DBS, based upon an analysis of connectivity and its relationship with gambling behaviour. Additional analyses suggested that this distinction may be mediated by the differential involvement of fibres connecting ventromedial subthalamic nucleus and orbitofrontal cortex. These findings identify a mechanistic substrate of neuropsychiatric impairment after STN-DBS and suggest that tractography could be used to predict the incidence of adverse neuropsychiatric effects. Clinically, these results highlight the importance of accurate electrode placement and careful stimulation titration in the prevention of neuropsychiatric side-effects after STN-DBS.

Who is taking care of the Chinese functionally impaired older people? The characteristics of family caregivers from China Health and Retirement Longitudinal Study

OBJECTIVE

To investigate caregiving in terms of personal, family and living arrangement among Chinese functionally impaired older people.

METHODS

A secondary cross-sectional analysis of data obtained from China Health and Retirement Longitudinal Study (CHARLS) was performed. Among 6,252 participants aged 65 years or older, people with at least one indicator of Activities of Daily Living Scales (ADLs) of disabilities were included in this research. Statistical analyses included chi-square tests and multiple logistic regression modelling.

RESULTS

Data of 973 functionally impaired people aged 65 and over, and 2772 adult offspring were extracted and analysed. The level of impairment, age, gender, marital status of the functionally impaired older people, adult offspring's income and living status were significantly associated with caregiving types.

CONCLUSION

This research describes the characteristics of functionally impaired older people and their caregivers, which may help improve the efficiency, quality and equity within the Chinese social care system.

Effect of deep brain stimulation on caregivers of patients with Parkinson's disease: A systematic review

BACKGROUND

Caregivers of patients with Parkinson's Disease (PD) often provide important support in the pre- and postoperative phase of Deep Brain Stimulation (DBS). DBS-associated changes of patient-functioning may affect caregiver wellbeing and impact the support system. Factors influencing caregiver-wellbeing under these circumstances are incompletely known.

OBJECTIVE

to systematically review studies of sufficient methodological quality on the impact of DBS on caregivers of PD patients.

METHODS

using PRISMA guidelines, major databases were searched up to May 2020. Five subcategories were identified: Caregiver burden, Caregiver cognitive and psychiatric functioning, Caregiver Quality of Life (QoL), Marital Satisfaction/Conflicts, and Caregiver Satisfaction. Quality was assessed using an in-house checklist.

RESULTS

293 studies were identified; 12 were ultimately included. Caregiver burden, psychiatric and cognitive functioning and QoL remained relatively unchanged. Results on marital satisfaction/conflicts were contrasting: an increase in marital conflicts despite improved relationship quality scores DBS. Caregiver satisfaction with surgery was low with 50-58% of caregivers being disappointed with DBS outcomes. Concerning caregiver related factors: a higher preoperative caregiver QoL, younger age, lower scores on psychiatric rating scales, and more favourable preoperative relationship quality scores, were associated with better caregiver wellbeing. A favourable patient-profile includes younger age and age-at-onset, shorter disease duration, lower medication requirements, and lower scores on psychiatric rating scales.

CONCLUSION

Although most patient- and caregiver-related subdomains remained unchanged after DBS, dissatisfaction among caregivers and marital problems may constitute a large risk for a well-functioning patient-caregiver dyad. Early recognition of potential problem situations may improve post-DBS care for both patients and caregivers.

Caregiver burden worsens in the second year after subthalamic nucleus deep brain stimulation for Parkinson's disease

BACKGROUND

Caregiver burden (CB) in Parkinson's disease (PD) does not improve in the short term after bilateral subthalamic nucleus (STN) deep brain stimulation (DBS), despite motor improvement. This may be due to increased caregiver demands after surgery or the possibility that DBS unresponsive non-motor factors, such as executive dysfunction, contribute to CB.

OBJECTIVE

To evaluate the trajectory of CB in year 2 following bilateral STN DBS surgery for PD, and to test whether post-operative CB changes correlate with changes in executive function in a subgroup with available neuropsychological testing.

METHODS

This retrospective analysis included 35 patients with PD whose caregivers completed the Caregiver Burden Inventory (CBI) at baseline and between 9 and 24 months after bilateral STN DBS. 14 of these patients had neuropsychological testing both at baseline and within 6 months of their follow up CBI assessment.

RESULTS

CBI scores showed worsened CB from baseline to follow-up (16.4-21.5, p = 0.006). There was no correlation between change in executive function and change in CBI in the smaller subsample.

CONCLUSION

CB worsens in the 2 years after bilateral STN DBS despite improvement in motor symptoms and is not associated with change in executive dysfunction in the setting of advancing PD. These findings have implications on pre-operative counselling for patients and caregivers considering DBS for PD.

Parkinson's Disease Caregiver Strain in Singapore

Background: Caregiver strain is recognized globally with Parkinson's disease (PD). Comparatively little is understood about caregiver burden and strain in Asia.

Objective: To investigate caregiver strain for families living with PD in Singapore, in light of international data.

Methods: Ninety-four caregivers were recruited via people living with idiopathic PD in Singapore. Caregiver strain was assessed using the Zarit Burden Interview (ZBI); health status was assessing using the Cumulative Illness Rating Scale for Geriatrics (CIRS-G). PD disability measures were the Unified Parkinson's Disease Rating Scale (UPDRS) and modified Hoehn and Yahr (1967) Scale.

Results: Primary caregivers of people living with PD in Singapore were mostly cohabiting spouses, partners or offspring. Around half employed foreign domestic helpers. Mean caregiving duration was 5.9 years with an average of eight hours per day spent in caregiving roles. Most care providers were comparatively healthy. Caregivers reported significant levels of strain which increased with greater level of disability (r = 0.36, n = 94, p < 0.001). Associations were significant between caregiver strain and scores on the UPDRS mentation, behavior, and mood subscales [r = 0.46, n = 94, p < 0.001, 95% CI (0.28, 0.60)]. High scores on the UPDRS activities of daily living subscale were associated with caregiver strain [r = 0.50, n = 94, p < 0.001, CI (0.33, 0.64)].

Conclusion: Most caregivers in this Singapore sample reported high levels of strain, despite comparatively good physical function. Caregiver strain in PD spans geopolitical and cultural boundaries and correlates with disease severity. These results support the need for better early recognition, education, and support for caregivers of people living with PD.

Impact of Supporting People with Advanced Parkinson's Disease on Carer's Quality of Life and Burden

PURPOSE

The aim of this study was to assess the burden and the quality of life (QoL) perceived by caregivers assisting advanced Parkinson's disease (PD) patients.

PATIENTS AND METHODS

Consecutive advanced PD patients treated with levodopa/carbidopa intestinal gel (LCIG) or continuous subcutaneous apomorphine infusion (CSAI) or care as usual (CU) and their care partners were recruited during routine visits according to a cross-sectional design. Caregiver's distress was assessed by Zarit Burden Interview (ZBI) and a QoL survey to evaluate and understand the burden experienced by care partners during family and working activities.

RESULTS

A total of 126 patients (53 LCIG, 19 CSAI and 54 CU) and their care partners were enrolled. The ZBI score boxplot showed that LCIG and CU populations have a similar distribution (ZBI inter-quartile range [IQR] values respectively 18-42 for LCIG and 19-43 for CU group), while the CSAI group has a wider score range (IQR 16-52). Caregivers assisting patients in treatment with LCIG have more time to perform family or household duties (p=0.0022), or to engage in leisure activities (p=0.0073) compared to CU, while no difference was found when compared to CSAI group. Approximately 50% of the care partners showed mood changes in the last 6 months and LCIG and CSAI had less impact on caregiver's mood compared to CU. Patients treated with LCIG were more independent in taking a bath or shower without assistance and were more able to move and walk without assistance.

CONCLUSION

Care partners of advanced PD patients treated with device-aided therapies have more time for their own life and a better perception of their QoL with a tendency to an improvement of mood compared with those of patients treated with CU.

The structural connectivity of discrete networks underlies impulsivity and gambling in Parkinson’s disease

See O’Callaghan (doi:10.1093/brain/awz349) for a scientific commentary on this article.

Mosley et al. examine impulsivity and naturalistic gambling behaviours in patients with Parkinson’s disease. They link within-patient differences to the structural connectivity of networks subserving reward evaluation and response inhibition, and reveal pivotal roles for the ventral striatum and subthalamic nucleus within these networks.

Subjective estimates of uncertainty during gambling and impulsivity after subthalamic deep brain stimulation for Parkinson's disease

Subthalamic deep brain stimulation (DBS) for Parkinson’s disease (PD) may modulate chronometric and instrumental aspects of choice behaviour, including motor inhibition, decisional slowing, and value sensitivity. However, it is not well known whether subthalamic DBS affects more complex aspects of decision-making, such as the influence of subjective estimates of uncertainty on choices. In this study, 38 participants with PD played a virtual casino prior to subthalamic DBS (whilst ‘on’ medication) and again, 3-months postoperatively (whilst ‘on’ stimulation). At the group level, there was a small but statistically significant decrease in impulsivity postoperatively, as quantified by the Barratt Impulsiveness Scale (BIS). The gambling behaviour of participants (bet increases, slot machine switches and double or nothing gambles) was associated with this self-reported measure of impulsivity. However, there was a large variance in outcome amongst participants, and we were interested in whether individual differences in subjective estimates of uncertainty (specifically, volatility) were related to differences in pre- and postoperative impulsivity. To examine these individual differences, we fit a computational model (the Hierarchical Gaussian Filter, HGF), to choices made during slot machine game play as well as a simpler reinforcement learning model based on the Rescorla-Wagner formalism. The HGF was superior in accounting for the behaviour of our participants, suggesting that participants incorporated beliefs about environmental uncertainty when updating their beliefs about gambling outcome and translating these beliefs into action. A specific aspect of subjective uncertainty, the participant’s estimate of the tendency of the slot machine’s winning probability to change (volatility), increased subsequent to DBS. Additionally, the decision temperature of the response model decreased post-operatively, implying greater stochasticity in the belief-to-choice mapping of participants. Model parameter estimates were significantly associated with impulsivity; specifically, increased uncertainty was related to increased postoperative impulsivity. Moreover, changes in these parameter estimates were significantly associated with the maximum post-operative change in impulsivity over a six month follow up period. Our findings suggest that impulsivity in PD patients may be influenced by subjective estimates of uncertainty (environmental volatility) and implicate a role for the subthalamic nucleus in the modulation of outcome certainty. Furthermore, our work outlines a possible approach to characterising those persons who become more impulsive after subthalamic DBS, an intervention in which non-motor outcomes can be highly variable.

The site of stimulation moderates neuropsychiatric symptoms after subthalamic deep brain stimulation for Parkinson's disease

Deep brain stimulation of the subthalamic nucleus for Parkinson's disease is an established advanced therapy that addresses motor symptoms and improves quality of life. However, it has also been associated with neuropsychiatric symptoms such as impulsivity and hypomania. When significant, these symptoms can be distressing, necessitating psychiatric intervention. However, a comprehensive analysis of neurocognitive and neuropsychiatric outcomes with reference to the site of subthalamic stimulation has not been undertaken. We examined this matter in a consecutive sample of 64 persons with Parkinson's disease undertaking subthalamic deep brain stimulation. Participants were assessed with a battery of neuropsychiatric instruments at baseline and at repeated postoperative intervals. A psychiatrist identified patients with emergent, clinically-significant symptoms due to stimulation. The site of the active electrode contact and a simulated volume of activated tissue were evaluated with reference to putative limbic, associative and motor subregions of the subthalamic nucleus. We studied anatomical correlates of longitudinal neuropsychiatric change and delineated specific subthalamic regions associated with neuropsychiatric impairment. We tested the ability of these data to predict clinically-significant symptoms. Subthalamic stimulation within the right associative subregion was associated with inhibitory errors on the Excluded Letter Fluency task at 6-weeks (p = 0.023) and 13-weeks postoperatively (p = 0.0017). A cluster of subthalamic voxels associated with inhibitory errors was identified in the right associative and motor subregions. At 6-weeks, clinically-significant neuropsychiatric symptoms were associated with the distance of the active contact to the right associative subregion (p = 0.0026) and stimulation within the right associative subregion (p = 0.0009). At 13-weeks, clinically-significant symptoms were associated with the distance to the right (p = 0.0027) and left (p = 0.0084) associative subregions and stimulation within the right associative subregion (p = 0.0026). Discrete clusters of subthalamic voxels associated with high and low likelihood of postoperative neuropsychiatric symptoms were identified in ventromedial and dorsolateral zones, respectively. When a classifier was trained on these data, clinically-significant symptoms were predicted with an accuracy of 79%. These data underscore the importance of accurate electrode targeting, contact selection and device programming to reduce postoperative neuropsychiatric impairment. The ability to predict neuropsychiatric symptoms based on subthalamic data may permit anticipation and prevention of these occurrences, improving safety and tolerability.

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The site of subthalamic stimulation influences the emergence of neuropsychiatric symptoms.

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Stimulation in the associative subthalamic subregion leads to disinhibition.

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Psychiatrically ‘safe’ and ‘unsafe’ regions of the subthalamic nucleus can be identified.

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Clinically-significant symptoms can be predicted by the site and distribution of stimulation.

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Electrode placement and stimulation titration are key factors in the tolerability of this therapy.