Impulsive and compulsive behaviors in Parkinson's disease: Impact on quality of and satisfaction with life, and caregiver burden

Clinical management model for impulse control disorders in Parkinson's disease

Over the last decade, we have gained a better understanding of impulse control disorder in Parkinson's disease (PD-ICD), a medication complication in PD. Researchers were aware of its complexity and took efforts to learn more about its diagnostic and treatment possibilities. Nevertheless, clinical management for it is currently neglected. We conducted a narrative overview of literature published from 2012 to October 2023 on various aspects of clinical management for PD-ICD. A potential "susceptibility-catalytic-stress" model in the development of PD-ICD was proposed and a profile encoding predictors for PD-ICD was created. Based on these predictors, some methods for prediction were recently developed for better prediction, such as the polymorphic dopamine genetic risk score and the clinic-genetic ICD-risk score. A variety of treatment options, including dose reduction of dopamine receptor agonists (DAs), DAs removal, DAs switch, and add-on therapy, are investigated with inconsistent reports. Based on current findings, we developed a clinical management model prototype centered on prevention, consisting of prediction, prevention, follow-up and monitoring, therapy, and recurrence prevention, for clinical reference, and further proposed 4 key clinical management principles, including standardization, prediction centered, persistence, and whole course.

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.

Locus Coeruleus Integrity Is Linked to Response Inhibition Deficits in Parkinson's Disease and Progressive Supranuclear Palsy

Parkinson's disease (PD) and progressive supranuclear palsy (PSP) both impair response inhibition, exacerbating impulsivity. Inhibitory control deficits vary across individuals and are linked with worse prognosis, and lack improvement on dopaminergic therapy. Motor and cognitive control are associated with noradrenergic innervation of the cortex, arising from the locus coeruleus (LC) noradrenergic system. Here we test the hypothesis that structural variation of the LC explains response inhibition deficits in PSP and PD. Twenty-four people with idiopathic PD, 14 with PSP-Richardson's syndrome, and 24 age- and sex-matched controls undertook a stop-signal task and ultrahigh field 7T magnetization-transfer-weighted imaging of the LC. Parameters of "race models" of go- versus stop-decisions were estimated using hierarchical Bayesian methods to quantify the cognitive processes of response inhibition. We tested the multivariate relationship between LC integrity and model parameters using partial least squares. Both disorders impaired response inhibition at the group level. PSP caused a distinct pattern of abnormalities in inhibitory control with a paradoxically reduced threshold for go responses, but longer nondecision times, and more lapses of attention. The variation in response inhibition correlated with the variability of LC integrity across participants in both clinical groups. Structural imaging of the LC, coupled with behavioral modeling in parkinsonian disorders, confirms that LC integrity is associated with response inhibition and LC degeneration contributes to neurobehavioral changes. The noradrenergic system is therefore a promising target to treat impulsivity in these conditions. The optimization of noradrenergic treatment is likely to benefit from stratification according to LC integrity.SIGNIFICANCE STATEMENT Response inhibition deficits contribute to clinical symptoms and poor outcomes in people with Parkinson's disease and progressive supranuclear palsy. We used cognitive modeling of performance of a response inhibition task to identify disease-specific mechanisms of abnormal inhibitory control. Response inhibition in both patient groups was associated with the integrity of the noradrenergic locus coeruleus, which we measured in vivo using ultra-high field MRI. We propose that the imaging biomarker of locus coeruleus integrity provides a trans-diagnostic tool to explain individual differences in response inhibition ability beyond the classic nosological borders and diagnostic criteria. Our data suggest a potential new stratified treatment approach for Parkinson's disease and progressive supranuclear palsy.

Contributory Factors to Caregiver Burden in Parkinson's Disease

Background

Although there is growing recognition of the relevancy of informal caregivers there is scarce information on the contributory factors of caregiver burden in Parkinson's Disease (PD).

Objective

To identify the main associated factors to caregivers' burden in people caring for a person with PD.

Methods

We analyzed the data set from a multinational online survey the Parkinson's real-world impact assesSMent (PRISM) focusing on medication use, comorbidities, health-related quality of life, relationship changes and the use of healthcare and supportive care resources by people with PD and their carers. Structured questionnaires including the Parkinson's disease quality of life questionnaire (PDQ-39), non-motor symptoms questionnaire (NMSQuest) and the Questionnaire for impulsive-compulsive disorder in Parkinson's disease (QUIP) were applied. Caregiver burden was assessed by the Zarit Burden Interview (ZBI).

Results

In a cohort of 245 dyads (patient and respective caregiver), caregivers reported a mild to moderate burden. Carers' perception of PD impact in partnership, financial burden, hours of care, patient's age, hypersexuality and health-related quality of life (HRQoL) were found to be significant contributory factors to caregiver burden. Taken together these variables explained 66.8% of the variance in the Interpretation of the ZBI total score.

Conclusions

Caring for a person with PD entails substantial burden, particularly when the caregiver perceives greater changes in partnership dynamics, dedicates more time to caregiving tasks, has financial burden, and when the patient is older, reports worst HRQoL and has sexual compulsive urges.

Predictors of Burden in Carers of Patients with Impulse Control Behaviors in Parkinson's Disease

Background

Impulse control behaviors (ICBs) are problematic, reward-based behaviors, affecting 15% to 35% of patients with Parkinson's disease. Evidence exists of increased carer burden as a result of these behaviors; however, little is known about the variables mediating this effect and their management.

Objective

To identify factors predictive of carer burden in a cohort of patients with Parkinson's disease with ICBs to enable the development of targeted therapeutic interventions for carers.

Methods

Data were collected from 45 patients with clinically significant ICBs and their carers, including levodopa equivalent daily dosage, motor and neuropsychiatric symptoms, cognitive function, and ICB severity. Carer burden was quantified by Zarit Burden Interview (ZBI). Univariate analyses were performed using the Spearman rank correlation. Linear regression was used to create a multivariate model for predicting ZBI.

Results

Univariate analysis identified significant correlations between ZBI and patient total Neuropsychiatric Inventory (NPI) (r s = 0.50), 4 NPI subscores (agitation/aggression, r s = 0.41; depression/dysphoria, r s = 0.47; apathy/indifference, r s = 0.49; and irritability/lability, r s = 0.38; all P < 0.02), and the carer 28-item General Health Questionnaire (GHQ-28) (r s = 0.52, P < 0.0005). Multivariate linear regression retained total NPI and GHQ-28 scores and were collectively predictive of 36.6% of the variance in the ZBI.

Conclusions

Our study suggests that depressive symptoms and aspects of executive dysfunction (apathy and disinhibition) in the patient are potential drivers of carer burden in patients with ICBs. Such findings suggest the presence of executive difficulties and/or mood disturbance should point the clinician to inquire about burden in the caring role and encourage the carer to seek help for any of their own general health problems, which may compound carer burden.

Parkinson's disease and iatrogenic impulsive-compulsive behaviors: A case/non-case study to build a complete model of individual vulnerability

BACKGROUND AND AIMS

Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases. First-line medications consist of drugs that act by counteracting dopamine deficiency in the basal ganglia. Unfortunately, iatrogenic impulsive-compulsive behaviors (ICBs) can occur in up to 20% of PD patients over the course of their illness. ICBs must be considered multifactorial disorders that reflect the interactions of the medication with an individual's vulnerability and the underlying neurobiology of PD. We aimed to explore the predictive genetic, psychopathological and neurological factors involved in the development of ICBs in PD patients by building a complete model of individual vulnerability.

METHODS

The PARKADD study was a case/non-case study. A total of 225 patients were enrolled ("ICB" group, N = 75; "no ICB" group, N = 150), and 163 agreed to provide saliva samples for genetic analysis. Sociodemographic, neurological and psychiatric characteristics were assessed, and genotyping for the characterization of polymorphisms related to dopaminergic and opioid systems was performed.

RESULTS

Factors associated with "ICBs" were younger age of PD onset, personal history of ICB prior to PD onset and higher scores on the urgency and sensation seeking facets of impulsivity. No gene variant was significantly associated, but the association with the opioid receptor mu 1 (OPRM1) rs1799971 polymorphism was close to significance.

DISCUSSION AND CONCLUSIONS

The influence of gene-environment interactions probably exists, and additional studies are needed to decipher the possible role of the opioid system in the development of ICBs in PD patients.

Neuropsychiatric Symptoms in Parkinson’s Disease Patients Are Associated with Reduced Health-Related Quality of Life and Increased Caregiver Burden

Parkinson’s disease (PD) is a progressive neurodegenerative disorder resulting in reduced health-related quality of life (HR-QoL) of people with PD (PwP) and their caregivers. Furthermore, there is an accumulating burden on caregivers of patients in advanced stages of the disease. In previous studies, motor- and non-motor-symptoms of PwP have been identified to contribute to reduced HR-QoL and an increased caregiver burden. This cross-sectional observational study aimed to study the influence of neuropsychiatric symptoms measured with the Scale for Evaluation of Neuropsychiatric Disorders in Parkinson’s Disease (SEND-PD) questionnaire on the HR-QoL of PwP, as well as the caregiver burden. Analyses revealed a significant association between SEND-PD subscale mood/apathy and reduced HR-QoL in PwP, measured by the Parkinson’s disease quality of life questionnaire (PDQ-8) (p < 0.001). Furthermore, mood/apathy was significantly correlated with caregiver burden (p = 0.001) in the multiple linear regression analysis. Hence, neuropsychiatric symptoms were found to have a profound impact on the HR-QoL of PwP, as well as on caregiver burden. Since neuropsychiatric symptoms were one of the main predictors for caregiver burden, physicians of PwP should treat these symptoms to stabilize caregiver burden, as well as HR-QoL in PwP and their caregivers.

Machine learning-based prediction of impulse control disorders in Parkinson's disease from clinical and genetic data

Goal: Impulse control disorders (ICDs) are frequent non-motor symptoms occurring during the course of Parkinson’s disease (PD). The objective of this study was to estimate the predictability of the future occurrence of these disorders using longitudinal data, the first study using cross-validation and replication in an independent cohort. Methods: We used data from two longitudinal PD cohorts (training set: PPMI, Parkinson’s Progression Markers Initiative; test set: DIGPD, Drug Interaction With Genes in Parkinson’s Disease). We included 380 PD subjects from PPMI and 388 PD subjects from DIGPD, with at least two visits and with clinical and genetic data available, in our analyses. We trained three logistic regressions and a recurrent neural network to predict ICDs at the next visit using clinical risk factors and genetic variants previously associated with ICDs. We quantified performance using the area under the receiver operating characteristic curve (ROC AUC) and average precision. We compared these models to a trivial model predicting ICDs at the next visit with the status at the most recent visit. Results: The recurrent neural network (PPMI: 0.85 [0.80 – 0.90], DIGPD: 0.802 [0.78 – 0.83]) was the only model to be significantly better than the trivial model (PPMI: ROC AUC = 0.75 [0.69 – 0.81]; DIGPD: 0.78 [0.75 – 0.80]) on both cohorts. We showed that ICDs in PD can be predicted with better accuracy with a recurrent neural network model than a trivial model. The improvement in terms of ROC AUC was higher on PPMI than on DIGPD data, but not clinically relevant in both cohorts. Conclusions: Our results indicate that machine learning methods are potentially useful for predicting ICDs, but further works are required to reach clinical relevance.

Assessment of therapeutic strategies for management of impulse control disorder in Parkinson's disease

BACKGROUND

Impulse control disorders (ICD) occur frequently in individuals with Parkinson's disease. So far, prevention is the best treatment. Several strategies for its treatment have been suggested, but their frequency of use and benefit have scarcely been explored.

OBJECTIVE

To investigate which strategy is the most commonly used in a real-life setting and its rate of response.

METHODS

A longitudinal study was conducted. At the baseline evaluation, data on current treatment and ICD status according to QUIP-RS were collected. The treatment strategies were categorized as "no-change", dopamine agonist (DA) dose lowering, DA removal, DA switch or add-on therapy. At the six-month follow-up visit, the same tools were applied.

RESULTS

A total of 132 individuals (58.3% men) were included; 18.2% had at least one ICD at baseline. The therapeutic strategy most used in the ICD group was no-change (37.5%), followed by DA removal (16.7%), DA switch (12.5%) and DA lowering (8.3%). Unexpectedly, in 20.8% of the ICD subjects the DA dose was increased. Overall, nearly 80% of the subjects showed remission of their ICD at follow-up.

CONCLUSIONS

Regardless of the therapy used, most of the subjects presented remission of their ICD at follow-up Further research with a longer follow-up in a larger sample, with assessment of decision-making processes, is required in order to better understand the efficacy of strategies for ICD treatment.

Risk factors of impulsive-compulsive behaviors in PD patients: a meta-analysis

OBJECTIVE

To summarize the reliable risk factors of impulsive-compulsive behaviors (ICBs) in Parkinson's disease (PD) patients through a meta-analysis on studies in which PD-ICBs were diagnosed by clinical interview.

METHODS

PubMed, Embase, Web of Science, CNKI and Wanfang databases were searched. We selected studies ensuring that diagnosis of ICBs in PD patients depends on semi-structured interviews according to the clinical diagnostic criteria of ICBs. The Newcastle-Ottawa Scale was used to evaluate quality of the included studies. The analyzed factors included demographic information, clinical characteristics of PD and medications.

RESULTS

A total of 856 records were screened and 66 full texts were evaluated, and 13 studies (684 PD patients with ICBs [PD-ICBs] and 3,382 PD patients without ICBs [PD-non-ICBs]) were included. Compared with PD-non-ICBs, PD-ICBs were younger in age (- 3.7 [- 5.53, - 1.87], P < 0.0001), with a greater proportion of males (1.64 [1.21, 2.22], P = 0.001), with a younger age of PD onset (- 5.42 [- 7.87, - 2.97], P < 0.0001) and a longer course of PD (1.30 [0.38, 2.22], P = 0.005). PD-ICBs were also associated with higher HAM-D (1.74 [0.47, 3.01], P = 0.007), more levodopa dosage (1.74 [1.09, 2.77], P = 0.02) and dopamine receptor agonists (DA) use (3.96 [2.74, 5.71), P < 0.00001), and higher average dose (levodopa 117.53 [53.59, 181.46], P = 0.0003; DA 80.03 [46.16, 113.90], P < 0.00001), as well as more amantadine use (2.20 [1.42, 3.40], P = 0.0004). The meta-analysis of most factors showed less heterogeneity, except age, age of onset, PD duration, Hoehn and Yahr stage, MMSE and drug dosage. However, whether rapid eye movement sleep behavior disorder, dyskinesia, genetic polymorphism and other factors are risk factors for PD-ICBs remains unclear.

CONCLUSION

This meta-analysis suggests that males, young, early disease onset, long disease duration, depression, dose of levodopa, dopamine receptor agonists and amantadine are risk factors of ICBs in PD patients.

Impulse control disorders and related behaviors in Parkinson's disease: risk factors, clinical and genetic aspects, and management

PURPOSE OF REVIEW

To review recent findings and research directions on impulse control disorders and related behaviors (ICDRBs) in Parkinson's disease (PD).

RECENT FINDINGS

Longitudinal studies found that prevalence increases during PD progression, incident ICDRBs being around 10% per year in patients treated with dopaminergic therapies. Screening tools and severity scales already developed have been validated and are available in several countries and languages. The main clinical risk factors include young age, male gender, type, doses and duration of dopaminergic therapy, PD motor severity and dyskinesia, depression, anxiety, apathy, sleep disorders, and impulsivity traits. Genetic factors are suspected by a high estimated heritability, but individual genes and variants remain to be replicated. Management of ICDRBs is centered on dopamine agonist decrease, with the risk to develop withdrawal symptoms. Cognitive behavioral therapy and subthalamic nucleus deep brain stimulation also improve ICDRBs. In the perspective of precision medicine, new individual prediction models of these disorders have been proposed, but they need further independent replication.

SUMMARY

Regular monitoring of ICDRB during the course of PD is needed, particularly in the subject at high risk of developing these complications. Precision medicine will require the appropriate use of machine learning to be reached in the clinical setting.