Impulsive and Compulsive Behaviors in Parkinson's Disease: The Norwegian ParkWest Study

Behavioral disorders in Parkinson disease: current view

Patients with Parkinson disease (PD) frequently experience several behavioral symptoms, such as anxiety, apathy, irritability, agitation, impulsive control and obsessive-compulsive or REM sleep behavior disorders, which can cause severe psychosocial problems and impair quality of life. Occurring in 30-70% of PD patients, these symptoms can manifest at early stages of the disease, sometimes even before the appearance of classic motor symptoms, while others can develop later. Behavioral changes in PD show distinct patterns of brain atrophy, dopaminergic and serotonergic deterioration, altered neuronal connectivity in frontostriatal, corticolimbic, default mode and other networks due to a cascade linking molecular pathologies and deficits in multiple behavior domains. The changes suggest a multi-system neurodegenerative process in the context of a specific α-synucleinopathy inducing a variety of biochemical and functional changes, the neurobiological basis and clinical relevance of which await further elucidation. This paper is intended to review the recent literature with focus on the main behavioral disturbances in PD patients, their epidemiology, clinical features, risk factors, animal models, neuroimaging findings, pathophysiological backgrounds, and treatment options of these deleterious lesions.

Evaluation of risk factors for impulse control disorder in Parkinson's disease in northern China

INTRODUCTION

Impulse control disorder (ICD) is a common non-motor symptom of Parkinson's disease (PD), but its risk factors are still controversial. This study aimed to determine the prevalence of ICD in northern China and analyze the risk factors associated with ICD, multiple ICDs, and four subtypes.

METHODS

A total of 285 PD patients were enrolled in this study. Each patient was screened using the Questionnaire for Impulse and Compulsive Control Disorders (QUIP). Stepwise regression analysis was performed to identify independent risk factors, and a prediction model was developed.

RESULTS

The prevalence of ICD in the study population was 11.6%. Stepwise regression analysis showed that ICD was associated with disease duration, motor symptoms, dyskinesia, depression, REM sleep behavior disorder (RBD) and cognitive decline; multiple ICDs were related to coffee history, motor symptoms, dyskinesia, depression, apathy and RBD. The prediction model demonstrated good performance with AUC values of 0.93, 0.88, and 0.66 on the balanced train set, balanced test set, and the original imbalanced data set, respectively.

CONCLUSION

The risk factors for PD-ICD are complex and influenced by regional economic and cultural backgrounds. Clarifying these factors and developing predictive models can help to delay or even prevent the development of ICD through early screening and intervention.

The mediating effects of depression, anxiety, and rapid eye movement sleep behavior disorder on the association between dopaminergic replacement therapy and impulse control disorders in Parkinson's disease

OBJECTIVES

This study aims to longitudinally explore whether and how rapid eye movement sleep behavior disorder (RBD), depression, and anxiety mediate the association between dopaminergic replacement therapy (DRT) and impulse control disorders (ICDs) in patients with Parkinson's disease (PD).

METHODS

Subjects were selected from the Parkinson's Progression Markers Initiative. After excluding missing data, 268, 223, 218, 238, and 219 patients with PD diagnosed at 12, 24, 36, 48, and 60 months prior, respectively, were included. We used the Questionnaire for Impulsive-Compulsive Disorders, RBD Screening Questionnaire, Geriatric Depression Scale, and State-Trait-Anxiety Inventory to assess ICBs, RBD, depression, and anxiety, respectively. We constructed three causal mediation analysis models to infer potential contingent pathways from DRT to ICD mediated by depression, anxiety, and RBD separately.

RESULTS

DRT was associated with an increased risk of PD incidence. Aggravation of ICDs was partly explained by improvements in depression (the average causal mediation effect accounted for 8.0% of the total effect) and RBD (the average causal mediation effect of RBD accounted for 16.4% of the total effect). This suggested that anxiety (the average causal mediation effect accounted for 12.7% of the total effect) plays a mediating role.

CONCLUSIONS

Focusing on changes in RBD, depression, and anxiety associated with hyperdopaminergic status should be an essential part of strategies to prevent ICDs in patients with Parkinson's disease.

Drug-Induced Gambling Disorder: Epidemiology, Neurobiology, and Management

Problematic gambling has been suggested to be a possible consequence of dopaminergic medications used mainly in neurological conditions, i.e. pramipexole and ropinirole, and possibly by one antipsychotic compound, aripiprazole. Patients with Parkinson's disease, restless legs syndrome and other conditions potentially treated with dopamine agonists, as well as patients treated for psychotic disorders, are vulnerable patient groups with theoretically increased risk of developing gambling disorder (GD), for example due to higher rates of mental ill-health in these groups. The aim of the present paper is to review the epidemiological, clinical, and neurobiological evidence of the association between dopaminergic medications and GD, and to describe risk groups and treatment options. The neurobiology of GD involves the reward and reinforcement system, based mainly on mesocorticolimbic dopamine projections, with the nucleus accumbens being a crucial area for developing addictions to substances and behaviors. The addictive properties of gambling can perhaps be explained by the reward uncertainty that activates dopamine signaling in a pathological manner. Since reward-related learning is mediated by dopamine, it can be altered by dopaminergic medications, possibly leading to increased gambling behavior and a decreased impulse control. A causal relationship between the medications and GD seems likely, but the molecular mechanisms behind this association have not been fully described yet. More research is needed in order to fully outline the clinical picture of GD developing in patient groups with dopaminergic medications, and data are needed on the differentiation of risk in different compounds. In addition, very few interventional studies are available on the management of GD induced by dopaminergic medications. While GD overall can be treated, there is need for treatment studies testing the effectiveness of tapering of the medication or other gambling-specific treatment modalities in these patient groups.

Treatment for cognitive and neuropsychiatric non-motor symptoms in Parkinson's disease: current evidence and future perspectives

INTRODUCTION

Non-motor symptoms (NMS) affect patients with Parkinson's disease (PD) from the prodromal to the advanced stages. NMS phenotypes greatly vary and have a huge impact on patients' and caregivers' quality of life (QoL). The management of cognitive and neuropsychiatric NMS remains an unmet need.

AREAS COVERED

The authors, herein, review the dopaminergic and non-dopaminergic pathogenesis, clinical features, assessment, and pharmacological and non-pharmacological treatments of cognitive and neuropsychiatric NMS in PD. They discuss the current evidence and report the findings of an overview of ongoing trials on pharmacological and selected non-pharmacological strategies.

EXPERT OPINION

The treatment of cognitive and neuropsychiatric NMS in PD is poorly explored, and therapeutic options are unsatisfactory. Pharmacological treatment of cognitive NMS is based on symptomatic active principles used in Alzheimer's disease. Dopamine agonists, selective serotonin, and serotonin-norepinephrine reuptake inhibitors have some evidence on PD-related depression. Clozapine, quetiapine, and pimavanserin may be considered for psychosis in PD. Evidence on the treatment of other neuropsychiatric NMS is limited or lacking. Addressing pathophysiological and clinical issues, which hamper solid evidence on the treatment of cognitive and neuropsychiatric NMS, may reduce the impact on QoL for PD patients and their caregivers.

Behavioral and psychological symptoms in neurodegenerative dementias: harbinger, follower, or constant collateral?

Neurodegenerative dementias such as the behavioral variant of frontotemporal dementia, Alzheimer's disease, and Parkinson's disease dementia are linked to various behavioral and psychological abnormalities. Whether these abnormalities precede, coincide or follow the onset of cognitive symptoms is still controversial in existing literature, with trajectories available so far dependent on types of dementia. The authors aim to review the different kinds of premorbid behavioral symptoms/personality traits associated with an increased risk of developing specific types of neurodegenerative dementia. Neuroticism has been associated with an increased risk of Alzheimer's disease and late-onset behavioral abnormalities with the behavioral variant of frontotemporal dementia. The presence of obsessive-compulsive spectrum disorders in Parkinson's disease dementia is also not rare. Analyzing this evidence, we propose "behavioral biomarkers" as neuroticism in Alzheimer's disease, late-onset behavioral abnormalities in behavioral variant of frontotemporal dementia, and obsessive-compulsive traits in Parkinson's disease dementia. These noninvasive behavioral biomarkers will be of immense help, particularly in developing countries, and will prevent the need for costlier investigations and aid in therapeutic strategies.

Neural correlates of risky decision making in Parkinson’s disease patients with impulse control disorders

Some patients with Parkinson's disease (PD) experience impulse control disorders (ICDs), characterized by deficient voluntary control over impulses, drives, or temptations regarding excessive hedonic behavior. The present study aimed to better understand the neural basis of impulsive, risky decision making in PD patients with ICDs by disentangling potential dysfunctions in decision and outcome mechanisms. We collected fMRI data from 20 patients with ICDs and 28 without ICDs performing an information gathering task. Patients viewed sequences of bead colors drawn from hidden urns and were instructed to infer the majority bead color in each urn. With each new bead, they could choose to either seek more evidence by drawing another bead (draw choice) or make an urn-inference (urn choice followed by feedback). We manipulated risk via the probability of bead color splits (80/20 vs. 60/40) and potential loss following an incorrect inference ($10 vs. $0). Patients also completed the Barratt Impulsiveness Scale (BIS) to assess impulsivity. Patients with ICDs showed greater urn choice-specific activation in the right middle frontal gyrus, overlapping the dorsal premotor cortex. Across all patients, fewer draw choices (i.e., more impulsivity) were associated with greater activation during both decision making and outcome processing in a variety of frontal and parietal areas, cerebellum, and bilateral striatum. Our findings demonstrate that ICDs in PD are associated with differences in neural processing of risk-related information and outcomes, implicating both reward and sensorimotor dopaminergic pathways.

Trait Anxiety as a Risk Factor for Impulse Control Disorders in de novo Parkinson's Disease

BACKGROUND

In addition to the well-known motor symptoms, patients with Parkinson's disease (PD) also frequently experience disabling non-motor symptoms including impulse control disorders (ICDs). ICDs are characterized by a loss of voluntary control over impulses, drives, or temptations regarding excessive hedonic behavior.

OBJECTIVE

The present study examined whether depression and anxiety in de novo PD patients predict the prospective development of ICDs.

METHODS

We selected 330 de novo PD patients from the Parkinson's Progression Markers Initiative database who were free of ICDs at the start of the study. ICD presence at baseline and follow-up assessments was evaluated via the shortened version of the Questionnaire for Impulsive-Compulsive Disorders (QUIP-S). Baseline depression and anxiety were measured via the Geriatric Depression Scale (GDS-15) and State-Trait-Anxiety Inventory (STAI-Y), respectively.

RESULTS

A total of 149 participants (45.2%) developed an ICD at follow-up and average time of ICD onset was 35 months after baseline. Results of a Cox regression analysis showed that STAI-Y scores but not GDS-15 scores significantly predicted ICD presence. Specifically, scores reflecting higher trait anxiety were associated with an increased risk of developing an ICD. This effect was not confounded by age, gender or UPDRS motor score. We also replicated the well-established result that dopamine agonist use is predictive of ICDs.

CONCLUSION

Our findings indicate that higher anxiety levels in de novo PD patients represent a risk factor for ICD development during the course of the disorder. This highlights the need for early and routine based anxiety screening in these patients.

The motor inhibitory network in patients with asymmetrical Parkinson's disease: An fMRI study

Recent imaging studies with the stop-signal task in healthy individuals indicate that the subthalamic nucleus, the pre-supplementary motor area and the inferior frontal gyrus are key components of the right hemisphere “inhibitory network”. Limited information is available regarding neural substrates of inhibitory processing in patients with asymmetric Parkinson’s disease. The aim of the current fMRI study was to identify the neural changes underlying deficient inhibitory processing on the stop-signal task in patients with predominantly left-sided Parkinson’s disease. Fourteen patients and 23 healthy controls performed a stop-signal task with the left and right hands. Behaviorally, patients showed delayed response inhibition with either hand compared to controls. We found small imaging differences for the right hand, however for the more affected left hand when behavior was successfully inhibited we found reduced activation of the inferior frontal gyrus bilaterally and the insula. Using the stop-signal delay as regressor, contralateral underactivation in the right dorsolateral prefrontal cortex, inferior frontal and anterior putamen were found in patients. This finding indicates dysfunction of the right inhibitory network in left-sided Parkinson’s disease. Functional connectivity analysis of the left subthalamic nucleus showed a significant increase of connectivity with bilateral insula. In contrast, the right subthalamic nucleus showed increased connectivity with visuomotor and sensorimotor regions of the cerebellum. We conclude that altered inhibitory control in left-sided Parkinson’s disease is associated with reduced activation in regions dedicated to inhibition in healthy controls, which requires engagement of additional regions, not observed in controls, to successfully stop ongoing actions.

Prevalence and Cumulative Incidence of Caregiver-Reported Aggression in Advanced Parkinson Disease and Related Disorders

Objective

To estimate the point prevalence and cumulative incidence of caregiver-reported aggressive behaviors among people living with advanced Parkinson disease and related disorders (PDRDs) and secondarily examine variables associated with aggression.

Methods

Caregivers from a clinical trial of outpatient palliative care for PDRD were surveyed about patient aggression at baseline and every 3 months over 12 months. Baseline responses were used for point prevalence. Cumulative incidence was calculated using responses from caregivers with no reported baseline aggression and available data at all other time points. Measures of disease severity, quality of life, mood, and caregiver burden were included in correlation and relative risk models, adjusting for age, sex, and diagnosis.

Results

Of 170 caregivers, 31 (18.2%) reported physical aggression, and 18 (10.6%) reported sexual aggression. Twelve-month cumulative incidence for physical and sexual aggression was 21.1% (23/109) and 16.0% (19/119), respectively. Physical aggression cumulative incidence was associated with patient depression (r = 0.37), patient-perceived quality of life (r = -0.26), caregiver burden (r = 0.26), caregiver-perceived patient quality of life (r = -0.26), and caregiver anxiety (r = 0.20). Age, sex, cognitive impairment, and dementia were not associated with aggression. No variables were associated with cumulative sexual aggression.

Conclusion

There was a high prevalence and incidence of aggression in our PDRD cohort. This is an understudied issue in PDRD, and our findings highlight the need for increased awareness among neurologists. Providers should consider assessing for aggression when discussing neuropsychiatric symptoms or screening for caregiver burden. Future research should examine the relationship between aggression and patient and caregiver health outcomes.

Trial Registration Information

Clinical trial registration number: NCT02533921.

Validation of the Chinese Version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease

Background: Impulse control and related disorders (ICRDs) have gained recognition as a severe complication of Parkinson's disease (PD) and are connected to poor quality of life and devastating financial and social problems. This study aimed to evaluate the usefulness of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) and estimate the risk factors for ICRDs in Chinese patients with PD. Methods: 207 PD patients were assessed using the QUIP and evaluated for PD motor and nonmotor symptoms. ICRDs were diagnosed via interviews of patients or their caregivers, and the clinical characteristics of patients with and without ICRDs were compared. Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the C-QUIP were 95.0, 83.4, 38.0, 99.4, and 84.5%. The prevalence of each disorder among participants diagnosed via interview was pathological gambling (0.5%), hypersexuality (1.9%), compulsive shopping (1.0%), binge eating (3.9%), hobbyism (1.9%), punding (0.5%), walkabout (0.5%), and dopamine dysregulation syndrome (2.9%). PD patients with ICRDs had longer PD duration, higher Hoehn and Yahr stage, Non-Motor Symptoms Scale (NMSS), and Hamilton-Depression Rating Scale (HAMD). Also, they received a larger total daily levodopa equivalent dose (LED), levodopa dosage, and dopamine agonist only LED (DA-LED) than did PD patients without ICRDs. Conclusions: Given its psychometric properties, the C-QUIP is a valid and rapid screening instrument for assessing of ICRDs in PD patients. Higher Hoehn and Yahr staging, NMSS and HAMD scores, a larger mean LED and levodopa dosage are risk factors for ICRDs.

[Speech and behavioral contaminations as non-epileptic automatic behavior in Parkinson's disease]

Parkinson's disease is characterized by a variety of motor and non-motor symptoms. More than two hundred years have passed since its description, but we still discover its new manifestations. Abnormal behaviors include impulse control disorders, dopamine dysregulation syndrome, psychotic disorders and others. However, two new phenomena have been recently described in patients with PD. It can manifest in the form of doing inappropriate actions which patient doesn't recognize, or pronouncing/writing unsuitable words and phrases. Patients can't remember such episodes, but find «signs» of their unconscious activity or hear about it from attestors. This article represents a review of literature on unrelated communication interlude and automatic behavior in Parkinson's disease and discusses its possible reasons.

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.

Low-Expressing Synucleinopathy Mouse Models Based on Oligomer-Forming Mutations and C-Terminal Truncation of α-Synuclein

α-synuclein (αSyn) is the main protein component of Lewy bodies, intracellular inclusions found in the brain of Parkinson's disease (PD) patients. Neurotoxic αSyn species are broadly modified post-translationally and, in patients with genetic forms of PD, carry genetically encoded amino acid substitutions. Mutations and C-terminal truncation can increase αSyn oligomerization and fibrillization. Although several genetic mouse models based on αSyn mutations and/or truncations exist, there is still a lack of mouse models for synucleinopathies not relying on overexpression. We report here two synucleinopathy mouse models, which are based on a triple alanine to proline mutation and a C-terminal truncation of αSyn, but do not overexpress the mutant protein when compared to the endogenous mouse protein. We knocked hαSyn ^TP or hαSyn^Δ119 (h stands for "human") into the murine αSyn locus. hαSyn^TP is a structure-based mutant with triple alanine to proline substitutions that favors oligomers, is neurotoxic and evokes PD-like symptoms in Drosophila melanogaster. hαSyn^Δ119 lacks 21 amino acids at the C-terminus, favors fibrillary aggregates and occurs in PD. Knocking-in of hαSyn ^TP or hαSyn^Δ119 into the murine αSyn locus places the mutant protein under the control of the endogenous regulatory elements while simultaneously disrupting the mαSyn gene. Mass spectrometry revealed that hαSyn ^TP and hαSyn^Δ119 mice produced 12 and 10 times less mutant protein, compared to mαSyn in wild type mice. We show phenotypes in 1 and 1.5 years old hαSyn ^TP and hαSyn^Δ119 mice, despite the lower levels of hαSyn^TP and hαSyn^Δ119 expression. Direct comparison of the two mouse models revealed many commonalities but also aspects unique to each model. Commonalities included strong immunoactive state, impaired olfaction and motor coordination deficits. Neither model showed DAergic neuronal loss. Impaired climbing abilities at 1 year of age and a deviant gait pattern at 1.5 years old were specific for hαSyn^Δ119 mice, while a compulsive behavior was exclusively detected in hαSyn ^TP mice starting at 1 year of age. We conclude that even at very moderate levels of expression the two αSyn variants evoke measurable and progressive deficiencies in mutant mice. The two transgenic mouse models can thus be suitable to study αSyn-variant-based pathology in vivo and test new therapeutic approaches.

Ethnic Variation in the Manifestation of Parkinson's Disease: A Narrative Review

The global prevalence of Parkinson's disease is increasing, yet the characteristics, risk factors and genetics of PD in Black, Asian and Hispanic populations is little understood. In this paper we review the published literature on clinical variation in the symptoms and signs of Parkinson's disease in different ethnic groups and responses to treatment. We included any study that sampled patients with Parkinson's disease from distinct ethnic backgrounds. We conclude that whilst there is little published evidence for ethnic variation in the clinical features of Parkinson's disease, there are substantial limitations and gaps in the current literature, which mean that the evidence does necessarily not fit with clinical observation. Possible explanations for expected differences in manifestation include genetic determinants, the co-existence of cerebrovascular disease and/or Alzheimer's disease pathology, healthcare inequalities and socio-cultural factors.

Impulse Control Disorders in Parkinson's Disease: From Bench to Bedside

Parkinson’s disease (PD) is a neurodegenerative disorder that is characterized by symptoms that impact both motor and non-motor domains. Outside of motor impairments, PD patients are at risk for impulse control disorders (ICDs), which include excessively disabling impulsive and compulsive behaviors. ICD symptoms in PD (PD + ICD) can be broadly conceptualized as a synergistic interaction between dopamine agonist therapy and the many molecular and circuit-level changes intrinsic to PD. Aside from discontinuing dopamine agonist treatment, there remains a lack of consensus on how to best address ICD symptoms in PD. In this review, we explore recent advances in the molecular and neuroanatomical mechanisms underlying ICD symptoms in PD by summarizing a rapidly accumulating body of clinical and preclinical studies, with a special focus on the utility of rodent models in gaining new insights into the neurochemical basis of PD + ICD. We also discuss the relevance of these findings to the broader problem of impulsive and compulsive behaviors that impact a range of neuropsychiatric syndromes.

Depression is Associated with Impulse-compulsive Behaviors in Parkinson's disease

BACKGROUND

Depression and impulse control disorders (ICDs) are both common in Parkinson's disease (PD) patients and their coexistence is frequent. Our aim was to determine the relationship between depression and impulsive-compulsive behaviors (ICBs) in a large cohort of PD patients.

METHODS

PD patients recruited from 35 centers of Spain from the COPPADIS cohort from January 2016 to November 2017 were included in the study. The QUIP-RS (Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale) was used for screening ICDs (cutoff points: gambling ≥6, buying ≥8, sex≥8, eating≥7) and compulsive behaviors (CBs) (cutoff points: hobbyism-punding ≥7). Mood was assessed with the BDI-II (Beck Depression Inventory - II) and major, minor, and subthreshold depression were defined.

RESULTS

Depression was more frequent in PD patients with ICBs than in those without: 66.3% (69/104) vs 47.5% (242/509); p<0.0001. Major depression was more frequent in this group as well: 22.1% [23/104] vs 14.5% [74/509]; p=0.041. Considering types of ICBs individually, depression was more frequent in patients with pathological gambling (88.9% [8/9] vs 50.2% [303/603]; p=0.021), compulsive eating behavior (65.9% [27/41] vs 49.7% [284/572]; p=0.032), and hobbyism-punding (69% [29/42] vs 49.4% [282/571]; p=0.010) than in those without, respectively. The presence of ICBs was also associated with depression (OR=1.831; 95%CI 1.048-3.201; p=0.034) after adjusting for age, sex, civil status, disease duration, equivalent daily levodopa dose, antidepressant treatment, Hoehn&Yahr stage, non-motor symptoms burden, autonomy for activities of daily living, and global perception of QoL.

LIMITATIONS

Cross-sectional design.

CONCLUSIONS

Depression is associated with ICBs in PD. Specifically, with pathological gambling, compulsive eating behavior, and hobbyism-punding.

Impulsivity Markers in Parkinsonian Subthalamic Single-Unit Activity

BACKGROUND

Impulsive-compulsive behaviors are common in Parkinson's disease (PD) patients. However, the basal ganglia dysfunctions associated with high impulsivity have not been fully characterized. The objective of this study was to identify the features associated with impulsive-compulsive behaviors in single neurons of the subthalamic nucleus (STN).

METHODS

We compared temporal and spectral features of 412 subthalamic neurons from 12 PD patients with impulsive-compulsive behaviors and 330 neurons from 12 PD patients without. Single-unit activities were extracted from exploratory microrecordings performed during deep brain stimulation (DBS) implant surgery in an OFF medication state.

RESULTS

Patients with impulsive-compulsive behaviors displayed decreased firing frequency during bursts and a larger fraction of tonic neurons combined with weaker beta coherence. Information carried by these features led to the identification of patients with impulsive-compulsive behaviors with an accuracy greater than 80%.

CONCLUSIONS

Impulsive-compulsive behaviors in PD patients are associated with decreased bursts in STN neurons in the OFF medication state. © 2021 International Parkinson and Movement Disorder Society.

Does the Country Make a Difference in Impulse Control Disorders? A Systematic Review

BACKGROUND

Impulse control disorders (ICDs) have an increased frequency in patients with Parkinson's disease (PD), mainly because of treatment with dopamine agonists (DA). Factors related with the country of origin (culture, economy, healthcare politics) may impact phenomenology.

OBJECTIVES

To explore phenomenology of ICDs depending on the country.

METHODS

A systematic review following PRISMA guidelines was performed using Pubmed database. Articles published up to 2018 in which the prevalence of ICDs was analyzed were selected.

RESULTS

Thirty-two studies from 22 countries worldwide were included. The highest prevalence of ICDs in each continent was found in UK (59%), USA (39.1%) and India (31.6%). Frequency of ICDs was higher in those studies with lower mean age, higher proportion of males, whenever a screening instrument was used and whenever prescription of DAs was more common. Prevalence of ICDs was higher in Western countries compared to Asian countries (20.8% vs. 12.8%, P < 0.001) as it was the proportion of patients treated with DAs (66% vs. 48.2%, P < 0.001). Hypersexuality was the most common ICD overall (up to 23.8%). The highest frequencies of compulsive buying and eating were found in Western countries. Gambling was less commonly diagnosed, but prevalence was relevant Japan (14%).

CONCLUSION

We observed a tendency towards a different ICD profile in different geographical areas, which may be attributable to socio-economical, cultural or political influences in the phenomenology of these disorders. Acknowledging these differences could help their early detection, which is critical for prognosis.

Co-occurrence of apathy and impulse control disorders in Parkinson disease

OBJECTIVE

To empirically test whether apathy and impulse control disorders (ICDs) represent independent, opposite ends of a motivational spectrum.

METHODS

In this single-center, cross-sectional study, we obtained retrospective demographics and clinical data for 887 patients with idiopathic Parkinson disease (PD) seen at a tertiary care center. Mood and motivation disturbances were classified using recommended cutoff scores from self-reported measures of apathy, ICD, anxiety, and depression.

RESULTS

Prevalence rates included 29.0% of patients with PD with depression, 40.7% with anxiety, 41.3% with apathy, 27.6% with ICDs, and 17.0% with both apathy and ICD. The majority (61.6%) of people reporting clinically significant ICDs also reported clinically significant apathy, and more than a third of patients with apathy (41.3%) also reported elevated ICD. Anxiety and depression were highest in patients with both apathy and ≥1 ICDs. Dopamine agonist use was higher in people with only ICD compared to people with only apathy. Mood significantly interacted with demographic variables to predict motivational disturbances.

CONCLUSIONS

Motivational disturbances are common comorbid conditions in patients with PD. In addition, these complex behavioral syndromes interact with mood in clinically important ways that may influence the design of future clinical trials and the development of novel therapies. This study challenges the concept of apathy and ICD in PD as opposite ends of a spectrum.

The experiences of carers looking after people with Parkinson's disease who exhibit impulsive and compulsive behaviours: An exploratory qualitative study

AIM

To understand the experiences of carers who were confronted by the development of impulsive and compulsive behaviours.

BACKGROUND

Impulsive and compulsive behaviours (ICBs) are a serious complication in Parkinson's disease (PD) strongly associated with dopamine replacement therapy used to treat patients. These behaviours comprise abnormal activities such as pathological gambling, binge eating, compulsive shopping and hypersexuality. These behaviours place a considerable burden on patients and on their carers and families.

DESIGN

An exploratory qualitative study.

METHODS

Using a convenience sampling approach, 13 carers were recruited to participate in semi-structured interviews. Interviews were conducted over the telephone. Verbatim transcripts were analysed using a thematic analysis approach. COREQ guidelines were adhered to in the reporting of this study.

RESULTS

Five main themes were identified: (a) realisation-developing awareness of ICB symptoms and their causes; (b) reacting-confronting and attempts to manage ICBs; (c) reaching out-help-seeking and selective disclosure; (d) reframing-shifting perspectives on ICBs over time; and (e) resignation-impact on relationships and facing the future.

CONCLUSIONS

The profound impact of ICBs on quality of life, relationships and economic stability was clear in the carers' accounts. Possible avenues for future clinical research are suggested.

RELEVANCE TO CLINICAL PRACTICE

The potentially devastating effects of ICBs provide a strong imperative for nurses and other health professionals to ensure that close monitoring for symptom development together with patient education is always part of practice.

Dopamine and reward hypersensitivity in Parkinson's disease with impulse control disorder

Impulse control disorders in Parkinson's disease are common neuropsychiatric complications associated with dopamine replacement therapy. Some patients treated with dopamine agonists develop pathological behaviours, such as gambling, compulsive eating, shopping, or disinhibited sexual behaviours, which can have a severe impact on their lives and that of their families. In this study we investigated whether hypersensitivity to reward might contribute to these pathological behaviours and how this is influenced by dopaminergic medication. We asked participants to shift their gaze to a visual target as quickly as possible, in order to obtain reward. Critically, the reward incentive on offer varied over trials. Motivational effects were indexed by pupillometry and saccadic velocity, and patients were tested ON and OFF dopaminergic medication, allowing us to measure the effect of dopaminergic medication changes on reward sensitivity. Twenty-three Parkinson's disease patients with a history of impulse control disorders were compared to 26 patients without such behaviours, and 31 elderly healthy controls. Intriguingly, behavioural apathy was reported alongside impulsivity in the majority of patients with impulse control disorders. Individuals with impulse control disorders also exhibited heightened sensitivity to exogenous monetary rewards cues both ON and OFF (overnight withdrawal) dopamine medication, as indexed by pupillary dilation in anticipation of reward. Being OFF dopaminergic medication overnight did not modulate pupillary reward sensitivity in impulse control disorder patients, whereas in control patients reward sensitivity was significantly reduced when OFF dopamine. These effects were independent of cognitive impairment or total levodopa equivalent dose. Although dopamine agonist dose did modulate pupillary responses to reward, the pattern of results was replicated even when patients with impulse control disorders on dopamine agonists were excluded from the analysis. The findings suggest that hypersensitivity to rewards might be a contributing factor to the development of impulse control disorders in Parkinson's disease. However, there was no difference in reward sensitivity between patient groups when ON dopamine medication, suggesting that impulse control disorders may not emerge simply because of a direct effect of dopaminergic drug level on reward sensitivity. The pupillary reward sensitivity measure described here provides a means to differentiate, using a physiological measure, Parkinson's disease patients with impulse control disorder from those who do not experience such symptoms. Moreover, follow-up of control patients indicated that increased pupillary modulation by reward can be predictive of the risk of future emergence of impulse control disorders and may thereby provide the potential for early identification of patients who are more likely to develop these symptoms.

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

INTRODUCTION

To disentangle the association between impulsive and compulsive behaviors (ICBs), health-related quality of life (HRQOL), satisfaction with life (SwL), and caregiver distress in dyads of people with Parkinson's disease (PwP) and caregivers.

METHODS

Data used in this study were obtained from the ongoing Norwegian ParkWest study, a population-based longitudinal cohort study of the incidence, neurobiology and prognosis of PD in Western Norway. One hundred and one dyads of PwP free of dementia and their caregivers were included 5 years after PD diagnosis and inclusion in the ParkWest study. Standardized clinical rating scales were used to evaluate ICBs, HRQOL, SwL and caregiver distress.

RESULTS

Of 101 PwP-caregiver dyads, self-reported ICBs were seen in 33% of PwP and only caregiver-reported ICBs in 12% of PwP. PwP-reported ICBs were associated with poorer HRQOL and SwL, whereas ICBs reported by caregivers only were associated with increased caregiver distress, but not poorer HRQOL or SwL in PwP.

CONCLUSIONS

ICBs have adverse effects on HRQOL, SwL and caregiver distress. These findings underpin the need for proper identification and management of ICBs in PwP.

Self-reported rates of impulsivity in Parkinson's Disease

OBJECTIVE

Impulsive decision-making is characterized by actions taken without considering consequences. Patients with Parkinson's disease (PD) who receive dopaminergic treatment, especially dopamine agonists, are at risk of developing impulsive-compulsive behaviors (ICBs). We assessed impulse-related changes across a large heterogeneous PD population using the Barratt impulsivity scale (BIS-11) by evaluating BIS-11 first- and second-order factors.

METHODS

We assessed a total of 204 subjects: 93 healthy controls (HCs), and 68 ICB- and 43 ICB + PD patients who completed the BIS-11. Using a general linear model and a least absolute shrinkage and selection operation regression, we compared BIS-11 scores between the HC, ICB- PD, and ICB + PD groups.

RESULTS

Patients with PD rated themselves as more impulsive than HCs in the BIS-11 total score, second-order attention domain, and first-order attention and self-control domains. ICB + patients recorded higher total scores as well as higher scores in the second-order non-planning domain and in self-control and cognitive complexity than ICB- patients.

INTERPRETATION

These results indicate that the patients with PD show particular problems with attentional control, whereas ICB + patients show a distinct problem in cognitive control and complexity. Additionally, it appears that all patients with PD are more impulsive than their age- and sex-matched healthy peers. Increased impulsivity may be a result of the disease course, or attributed to dopaminergic medication use, but these results emphasize the importance of the cognitive components of impulsivity in patients with PD.

Validation of the Korean Version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease Rating Scale

Background and Purpose

Impulse-control disorder is an important nonmotor symptom of Parkinson's disease (PD) that can lead to financial and social problems, and be related to a poor quality of life. A nationwide multicenter prospective study was performed with the aim of validating the Korean Version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease Rating Scale (K-QUIP-RS).

Methods

The K-QUIP-RS was constructed using forward and backward translation, and pretesting of the prefinal version. PD patients on stable medical condition were recruited from 27 movement-disorder clinics. Participants were assessed using the K-QUIP-RS and evaluated for parkinsonian motor and nonmotor statuses and for PD-related quality of life using a predefined evaluation battery. The test–retest reliability of the K-QUIP-RS was assessed over an interval of 10–14 days, and correlations between the KQUIP-RS and other clinical scales were analyzed.

Results

This study enrolled 136 patients. The internal consistency of the K-QUIP-RS was indicated by a Cronbach's α coefficient of 0.846, as was the test–retest reliability by a Guttman split-half coefficient of 0.808. The total K-QUIP-RS score was positively correlated with the scores for depression and motivation items on the Unified PD Rating Scale (UPDRS), Montgomery-Asberg Depression Scale, and Rapid-Eye-Movement Sleep-Behavior-Disorders Questionnaire. The total K-QUIP-RS score was also correlated with the scores on part II of the UPDRS and the PD Quality of Life-39 questionnaire, and the dopaminergic medication dose.

Conclusions

The K-QUIP-RS appears to be a reliable assessment tool for impulse-control and related behavioral disturbances in the Korean PD population.

Evolution of impulsive-compulsive behaviors and cognition in Parkinson's disease

The longitudinal course of ICBs in patients with Parkinson's disease (PwP) relative to controls has not been explored as of yet. The aim of this study is to determine the frequency, evolution and associated cognitive and clinical features of impulsive and compulsive behaviors (ICBs) over 4 years of prospective follow-up in a population-based cohort with early Parkinson's disease (PD). We recruited 124 cognitively intact participants with early PD and 156 matched controls from the Norwegian ParkWest study. ICBs were assessed using the self-report short form version of the Questionnaire for Impulsive-Compulsive Disorders in PD. Cognitive changes were examined in PwP with and without ICBs who completed the 4-year follow-up. Generalized linear mixed modelling and mixed linear regression were used to analyze clinical factors and cognitive changes associated with ICBs in PwP over time. ICBs were more common in PwP than controls at all visits, with an age-adjusted odds ratio (OR) varying between 2.5 (95% CI 1.1-5.6; p = 0.022) and 5.1 (95% CI 2.4-11.0; p < 0.001). The 4-year cumulative frequency of ICBs in PwP was 46.8% and 23.3% developed incident ICBs during the study period, but the presence of ICBs was non-persistent in nearly 30%. ICBs were independently associated with younger age (OR 0.95, 95% CI 0.91-0.99: p = 0.008) and use of dopamine agonist (OR 4.1, 95% CI 1.56-10.69). Cognitive changes over time did not differ between patients with and without ICBs. In conclusion, ICBs are common in PwP, but are often non-persistent and not associated with greater cognitive impairment over time.

Brain Imaging and Impulse Control Disorders in Parkinson's Disease

Purpose of Review

Parkinson’s disease (PD) has a wide spectrum of symptoms including the presence of psychiatric disease. At present, most treatment plans, comprised of dopaminergic drugs, are chronic and complex. Though dopaminergic agents are quite efficient in managing the motor aspects of the disease, chronic pharmacotherapy specifically with dopamine receptor agonists has been highly linked to the occurrence of Impulse Compulsive disorder (ICD), which can be problematic for individual patients.

Recent Findings

Much of what is known today about PD-related ICD stems from brain imaging studies, however, evidence is not quite conclusive. Research in the field has been focused on identifying the underlying mechanisms of PD-related ICD and understanding the functions of the structures involved in the reward network.

Summary

This article presents an update of recent findings from key neuroimaging studies in PD-related ICD, discusses results from controversial studies, and identifies areas for future research in the field.

Meta-analysis of related factors of impulse control disorders in patients with Parkinson's disease

BACKGROUND

To explore the related factors of impulse control disorders (ICDs) in patients with Parkinson's disease (PD).

METHODS

We conducted a comprehensive search to identify studies on impulse control disorders in patients with Parkinson's disease. The related factors were compared to discriminate between PD patients with ICDs (PD-ICDs+)and PD patients without ICDs(PD-ICDs-)by a meta-analysis.

RESULTS

96 full-texts were assessed, and 15 were included (PD-ICDs+: 999; PD-ICDs-: 3507). The results showed that PD-ICDs + were significantly associated with younger age (SMD =-0.39, 95% CI: -0.50 - -0.28, P < 0.01), male sex(OR = 1.64, 95% CI: 1.34-2.02, P < 0.01), smoking habit(OR = 2.28, 95% CI: 1.16-4.47,P = 0.02), dopamine receptor agonist use(DA use) (OR = 3.41, 95% CI: 1.86-6.26,P < 0.01), dopamine receptor agonist equivalent daily dose(DA LEDD) (SMD = 0.42, 95% CI: 0.14 - 0.70,P = 0.003), levodopa equivalent daily dose(total LEDD) (SMD = 0.32, 95% CI: 0.14 - 0.49,P < 0.01), and amantadine use(OR = 2.26, 95% CI: 1.67-3.06,P < 0.01). While levodopa dose (SMD = 0.05, 95% CI: -0.09 -0.19,P = 0.48), Hoehn and Yahr stage(H & Y stage) (SMD =-0.05, 95% CI: -0.14 - 0.04,P = 0.27), MDS-UPDRS Part III score(UPDRS III score) (SMD =-0.05, 95% CI: -0.13 - 0.03,P = 0.24), PD duration (SMD =-0.23, 95% CI: 0.10 - 0.37,P < 0.01)and Mini-Mental Status Examination score (MMSE score) (SMD = 0.10, 95% CI: -0.11 - 0.31,P = 0.33)were not related with PD-ICDs+.

CONCLUSION

Our study confirmed the previous results that younger age, male gender, smoking habit, longer PD duration, DA use, DA LEDD, total LEDD were high risk factors of PD-ICDs+.

Compulsive eating behaviors in Parkinson's disease

PURPOSE

Eating disorders are common in Parkinson's disease (PD) patients and often class in Impulse control disorders, however, little is known about their phenomenology. Specific symptoms and comorbidities were described in a group of PD patients in this preliminary study.

METHODS

Over a period of 6 months, 51 PD patients who experienced significant changes in eating habits following diagnosis of PD and were interviewed during regularly scheduled follow-up visits. We assessed each patient's height and weight, impulsivity, psychological distress, current eating disorder symptoms, food addiction, food habits and craving.

RESULTS

Among the PD patients who experienced modified dietary habits following diagnosis, few exhibited binge eating disorders (BED) full criteria (3.9%). However, 21.6% of patients experienced episodes of out-of-control eating with a large quantity of food in short time and 39.2% satisfied food addiction (FA) criteria without binge eating disorder. Food cravings more than once a week were experienced in approximately half of the population including all FA patients. Regarding comorbidities, FA PD patients present impulsive features and anxiety.

CONCLUSIONS

This study confirms the existence of FA profile in PD patients. Eating disorders even in PD are complex and have a cross-cutting criteria related to out-of-control eating, FA, and BED. The association of anxiety with PD-related food addiction, contrary to L-dopa equivalent daily dose mean score or the presence of dopamine agonists, underline the complex sustainability of the dopaminergic brainstem support. A study on their detailed prevalence in this population could be helpful to better understand unspecified feeding or eating disorder.

CLINICAL TRIAL NUMBER

DR-2012-007.

NAME OF THE REGISTRY

French Committee for the Protection of Persons (CPP) & French National Commission on Computing and Liberty (CNIL).

LEVEL OF EVIDENCE

Level V, descriptive study.

Impulse Control Disorders in Parkinson's Disease. A Brief and Comprehensive Review

Impulse control and related disorders (ICDs-RD) encompasses a heterogeneous group of disorders that involve pleasurable behaviors performed repetitively, excessively, and compulsively. The key common symptom in all these disorders is the failure to resist an impulse or temptation to control an act or specific behavior, which is ultimately harmful to oneself or others and interferes in major areas of life. The major symptoms of ICDs include pathological gambling (PG), hypersexualtiy (HS), compulsive buying/shopping (CB) and binge eating (BE) functioning. ICDs and ICDs-RD have been included in the behavioral spectrum of non-motor symptoms in Parkinson's disease (PD) leading, in some cases, to serious financial, legal and psychosocial devastating consequences. Herein we present the prevalence of ICDs, the risk factors, its pathophysiological mechanisms, the link with agonist dopaminergic therapies and therapeutic managements.

Impact of Cognitive Profile on Impulse Control Disorders Presence and Severity in Parkinson's Disease

Background: Impulse control disorders (ICDs) and related behaviors are frequent in Parkinson's disease (PD). Mild cognitive impairment (PD-MCI) and dementia (PDD), both characterized by heterogeneous cognitive phenotypes, are also commonly reported in PD. However, the frequency and severity of ICD within PD cognitive states is unknown.

Methods: Three hundred and twenty-six PD patients completed a comprehensive neuropsychological assessment and were classified as PD-MCI, PDD, or without cognitive alterations (PD-NC). The Minnesota impulsive disorders interview was used to ascertain the presence (ICD+) or absence (ICD–) of ICD. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale was used to assess ICD severity. A subsample of 286 patients evaluated with the same cognitive tasks was selected in order to investigate the characteristics of ICD in PD cognitive phenotypes.

Results: ICDs were present in 55% of PD-NC, in 50% of PD-MCI, and in 42% of PDD patients. Frequencies of ICD+ with attentive (ICD+: 20% vs. ICD–: 4%; p = 0.031) and executive impairments (ICD+: 44% vs. ICD–: 30%; p = 0.027) were higher in the PD-MCI and PDD subgroups, respectively. As expected, no differences were observed in the PD-NC. PD-MCI with attentive impairments presented higher percentage of ICD+ with deficits in the Trail Making Test B-A but not in the Digit Span Sequencing task. In PDD, executive failures concerned Similarities task (ICD+: 67%; ICD–: 29%; p = 0.035), with no differences between ICD+ and ICD– in the Stroop task.

Conclusions: Prevalence and severity of ICDs and related behaviors do not differ in PD with different cognitive states. However, ICD+ are more likely to show deficits, respectively in attentive and in executive domains, specifically in the Trail Making Test B-A task for the attention and working memory domain in PD-MCI and in the Similarities task for the executive function domain in PDD. Prospective studies should evaluate if these tests can be used as screening tool for ICDs in PD.

Impulsive-Compulsive Behaviours in Belgian-Flemish Parkinson's Disease Patients: A Questionnaire-Based Study

Background

Impulsive-compulsive behaviours (ICB) are a potentially harmful group of behavioural symptoms among the nonmotor aspects of Parkinson's disease (PD).

Objective

To develop and perform partial validation of a Belgian-Flemish version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) as a screening instrument for ICB in PD patients.

Methods

Using a translation-backtranslation method, we developed a Belgian-Flemish version of the QUIP, which was subsequently completed by 88 PD patients. QUIP-positive patients were invited for a semistructured diagnostic interview.

Results

A positive QUIP score for one or more ICB was observed in 37 patients (41%). In 15 patients (17%), a positive QUIP score for one or more impulse control disorders (ICD) was noted: pathological gambling in 1, hypersexuality in 8, compulsive shopping in 5, and compulsive eating in 8 patients. A positive QUIP score for punding, hobbyism, and/or walkabout was observed in 30 patients. The semistructured diagnostic interview was performed in 22 QUIP-positive patients. The diagnosis of ICB was confirmed in 6 patients, suggesting a positive predictive value of 27% for the Belgian-Flemish version of the QUIP.

Conclusions

We have developed a Belgian-Flemish version of the QUIP, which can be used as a screening questionnaire for ICB in PD patients. Our data suggest that sensitivity is high, specificity is low, and validity of the questionnaire is similar to the original version. We confirm the necessity of additional clinical assessment of QUIP-positive patients to ascertain a diagnosis of ICB.

Medications, Deep Brain Stimulation, and Other Factors Influencing Impulse Control Disorders in Parkinson's Disease

Impulse control disorders (ICDs) in Parkinson's disease (PD) have a high cumulative incidence and negatively impact quality of life. ICDs are influenced by a complex interaction of multiple factors. Although it is now well-recognized that dopaminergic treatments and especially dopamine agonists underpin many ICDs, medications alone are not the sole cause. Susceptibility to ICD is increased in the setting of PD. While causality can be challenging to ascertain, a wide range of modifiable and non-modifiable risk factors have been linked to ICDs. Common characteristics of PD patients with ICDs have been consistently identified across many studies; for example, males with an early age of PD onset and dopamine agonist use have a higher risk of ICD. However, not all cases of ICDs in PD can be directly attributable to dopamine, and studies have concluded that additional factors such as genetics, smoking, and/or depression may be more predictive. Beyond dopamine, other ICD associations have been described but remain difficult to explain, including deep brain stimulation surgery, especially in the setting of a reduction in dopaminergic medication use. In this review, we will summarize the demographic, genetic, behavioral, and clinical contributions potentially influencing ICD onset in PD. These associations may inspire future preventative or therapeutic strategies.

Dopaminergic Neurotransmission in Patients With Parkinson's Disease and Impulse Control Disorders: A Systematic Review and Meta-Analysis of PET and SPECT Studies

Background: Around 30% Parkinson's disease (PD) patients develop impulse control disorders (ICDs) to D_2/3 dopamine agonists and, to a lesser extent, levodopa. We aim to investigate striatal dopaminergic function in PD patients with and without ICD.

Methods: PubMed, Science Direct, EBSCO, and ISI Web of Science databases were searched (from inception to March 7, 2018) to identify PET or SPECT studies reporting striatal dopaminergic function in PD patients with ICD (ICD+) compared to those without ICD (ICD–). Studies which included drug naïve patients, explored non-pharmacological procedures (e.g., deep brain stimulation), and those using brain blood perfusion or non-dopaminergic markers were excluded. Standardized mean difference (SDM) was used and random-effect models were applied. Separate meta-analyses were performed for dopamine transporter level, dopamine release, and dopamine receptors availability in the putamen, caudate, dorsal, and ventral striatum.

Results: A total of 238 studies were title and abstract screened, of which 19 full-texts were assessed. Nine studies (ICD+: N = 117; ICD–: N = 175 patients) were included in the analysis. ICD+ showed a significant reduction of dopamine transporter binding in the putamen (SDM = −0.46; 95% CI: −0.80, −0.11; Z = 2.61; p = 0.009), caudate (SDM = −0.38; 95% CI: −0.73, −0.04; Z = 2.18; p = 0.03) and dorsal striatum (SDM = −0.45; 95% CI: −0.77, −0.13; Z = 2.76; p = 0.006), and increased dopamine release to reward-related stimuli/gambling tasks in the ventral striatum (SDM = −1.04; 95% CI: −1.73, −0.35; Z = 2.95; p = 0.003). Dopamine receptors availability did not differ between groups. Heterogeneity was low for dopamine transporter in the dorsal striatum (I² = 0%), putamen (I² = 0%) and caudate (I² = 0%), and pre-synaptic dopamine release in the dorsal (I² = 0%) and ventral striatum (I² = 0%); heterogeneity was high for dopamine transporter levels in the ventral striatum (I² = 80%), and for dopamine receptors availability in the ventral (I² = 89%) and dorsal (I² = 86%) striatum, putamen (I² = 93%), and caudate (I² = 71%).

Conclusions: ICD+ patients show lower dopaminergic transporter levels in the dorsal striatum and increased dopamine release in the ventral striatum when engaged in reward-related stimuli/gambling tasks. This dopaminergic imbalance might represent a biological substrate for ICD in PD. Adequately powered longitudinal studies with drug naïve patients are needed to understand whether these changes may represent biomarkers of premorbid vulnerability to ICD.

Impulse Control Disorder in Parkinson's Disease: A Meta-Analysis of Cognitive, Affective, and Motivational Correlates

Background: In Parkinson's disease (PD), impulse control disorders (ICDs) develop as side-effect of dopaminergic replacement therapy (DRT). Cognitive, affective, and motivational correlates of ICD in medicated PD patients are debated. Here, we systematically reviewed and meta-analyzed the evidence for an association between ICD in PD and cognitive, affective, and motivational abnormalities. Methods: A systematic review and meta-analysis was performed on PubMed, Science Direct, ISI Web of Science, Cochrane, EBSCO for studies published between 1-1-2000 and 8-3-2017 comparing cognitive, affective, and motivational measures in PD patients with ICD (ICD+) vs. those without ICD (ICD-). Exclusion criteria were conditions other than PD, substance and/or alcohol abuse, dementia, drug naïve patients, cognition assessed by self-report tools. Standardized mean difference (SMD) was used, and random-effect model applied. Results: 10,200 studies were screened (title, abstract), 79 full-texts were assessed, and 25 were included (ICD+: 625 patients; ICD-: 938). Compared to ICD-, ICD+ showed worse performance reward-related decision-making (0.42 [0.02, 0.82], p = 0.04) and set-shifting tasks (SMD = -0.49 [95% CI -0.78, -0.21], p = 0.0008). ICD in PD was also related to higher self-reported rate of depression (0.35 [0.16, 0.54], p = 0.0004), anxiety (0.43 [0.18, 0.68], p = 0.0007), anhedonia (0.26 [0.01, 0.50], p = 0.04), and impulsivity (0.79 [0.50, 1.09], p < 0.00001). Heterogeneity was low to moderate, except for depression (I² = 61%) and anxiety (I² = 58%). Conclusions: ICD in PD is associated with worse set-shifting and reward-related decision-making, and increased depression, anxiety, anhedonia, and impulsivity. This is an important area for further studies as ICDs have negative impact on the quality of life of patients and their caregivers.

The factors associated with impulse control behaviors in Parkinson's disease: A 2-year longitudinal retrospective cohort study

INTRODUCTION

Impulse control behaviors (ICBs) are impulsive-compulsive behaviors often associated with dopamine replacement therapy in Parkinson's disease (PD). Although remission can occur in ICB, only four reports on the ratio of remission and the persistence of ICB have been published, and the associated factors with ICB remission or persistence have been little known. Therefore, we conducted a longitudinal assessment of the remission, persistence, and development of ICB and those associated factors in patients with PD.

METHODS

We retrospectively investigated a PD database at Aomori Prefectural Central Hospital, Japan. One hundred and forty-eight patients with PD who could be followed up for 2 years were enrolled. ICB was assessed using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's disease. Motor severity (Hoehn and Yahr scale and United Parkinson's Disease Rating Scale), cognitive function (Mini-Mental State Examination), and other clinical variables (sex, age, onset age, disease duration, olfactory dysfunction, and dyskinesia) and medications used to treat PD were assessed. Univariate analyses were performed.

RESULTS

Seven patients were excluded because of the exclusion criteria, and 141 patients were analyzed. Thirty patients (21.3%) had ICB at baseline, and these patients also had significantly higher use of pergolide. The ICB remission rate was 60%, the ICB persistence ratio was 40%, and the ICB development ratio was 12.6% over 2 years. Statistically, younger age and pergolide use were associated with ICB persistence. Being male, having dyskinesia, and rotigotine, entacapone, zonisamide, and istradefylline use were associated with ICB development.

CONCLUSION

This study suggests that younger age and pergolide use may be the new associated factors with ICB persistence and that entacapone, zonisamide, and istradefylline use may be associated with the development of ICB. Drug profiles and medication practices in Japan may explain the association of these factors with ICB.

Impulse-Control Disorders in Parkinson's Disease: A Meta-Analysis and Review of Case-Control Studies

BACKGROUND

Although several case-control studies on the prevalence of Impulse-Control Disorders (ICDs) in Parkinson's Disease (PD) have been conducted, no meta-analytic study on this topic has previously been published. Thus, knowledge about the overall prevalence rate of ICD in PD and factors that might moderate this relationship is lacking.

METHOD

Prevalence studies of ICDs in PD were identified by computer searches in the MEDLINE, PsycINFO, and Web of Science databases, covering the period from January 2000 to February 2017. Data for N = 4,539, consisting of 2,371 PD patients and 2,168 healthy controls, representing 14 case-control studies were included. Estimation of the odds ratio (OR) of ICDs in PD compared to healthy controls was conducted using random-effects models. Mixed-effects models were applied in the moderator analysis of heterogeneity. Publication bias was estimated using a contour-enhanced funnel plot, the Rüker's test, and fail-safe N test for estimating the number of potential missing studies.

RESULTS

Overall, the results showed significantly higher ratios for several ICDs in PD compared to healthy controls with the estimated overall ORs ranging between 2.07, 95% CI [1.26, 3.48], for having any ICDs, and 4.26, 95% CI [2.17, 8.36], for hypersexuality. However, the random-effects results for shopping were non-significant, though the fixed-effects model was significant (OR = 1.66, 95%CI [1.21, 2.27]). The testing of potential moderator variables of heterogeneity identified the following two variables that were both associated with increased risk: being medically treated for PD and disease duration. The results must be interpreted with some caution due to possible small-studies effect or publication bias.

CONCLUSION

Individuals with PD seem to have a significantly greater risk of suffering from ICDs compared to healthy controls. Gambling, hypersexuality, eating, punding, and hobbying are all ICDs significantly associated with PDs being medically treated for PD.

Dopaminergic and Opioid Pathways Associated with Impulse Control Disorders in Parkinson's Disease

Introduction

Impulse control disorders (ICDs) are frequent non-motor symptoms in Parkinson’s disease (PD), with potential negative effects on the quality of life and social functioning. ICDs are closely associated with dopaminergic therapy, and genetic polymorphisms in several neurotransmitter pathways may increase the risk of addictive behaviors in PD. However, clinical differentiation between patients at risk and patients without risk of ICDs is still troublesome. The aim of this study was to investigate if genetic polymorphisms across several neurotransmitter pathways were associated with ICD status in patients with PD.

Methods

Whole-exome sequencing data were available for 119 eligible PD patients from the Norwegian ParkWest study. All participants underwent comprehensive neurological, neuropsychiatric, and neuropsychological assessments. ICDs were assessed using the self-report short form version of the Questionnaire for Impulsive-Compulsive Disorders in PD. Single-nucleotide polymorphisms (SNPs) from 17 genes were subjected to regression with elastic net penalization to identify candidate variants associated with ICDs. The area under the curve of receiver-operating characteristic curves was used to evaluate the level of ICD prediction.

Results

Among the 119 patients with PD included in the analysis, 29% met the criteria for ICD and 63% were using dopamine agonists (DAs). Eleven SNPs were associated with ICDs, and the four SNPs with the most robust performance significantly increased ICD predictability (AUC = 0.81, 95% CI 0.73–0.90) compared to clinical data alone (DA use and age; AUC = 0.65, 95% CI 0.59–0.78). The strongest predictive factors were rs5326 in DRD1, which was associated with increased odds of ICDs, and rs702764 in OPRK1, which was associated with decreased odds of ICDs.

Conclusion

Using an advanced statistical approach, we identified SNPs in nine genes, including a novel polymorphism in DRD1, with potential application for the identification of PD patients at risk for ICDs.

Algorithms for the treatment of motor problems in Parkinson's disease

Several different strategies are effective for medical treatment of motor problems in Parkinson's disease (PD). Many guidelines and evidence-based reviews are available, but there is no documentation or consensus in favor of just one treatment strategy. This review presents two algorithms that may be helpful when deciding how to treat a PD patient at various stages of the disease. The first algorithm suggests one way to treat PD from the first onset of motor symptoms. It is largely based on treatment recommendations from the Scandinavian countries and Germany. The other algorithm is meant as assistance for choosing among the different device-aided treatments for advanced PD. There is not sufficient comparative data to recommend one particular line of treatment, neither in early PD nor in advanced disease with motor complications. Individualized treatment is needed for each patient. The current algorithms only represent an alternative for aiding treatment decisions.

Cognitive and behavioral disorders in Parkinson's disease: an update. II: behavioral disorders

Patients with Parkinson's disease (PD) can experience several behavioral symptoms, such as apathy, agitation, hypersexuality, stereotypic movements, pathological gambling, abuse of antiparkinsonian drugs, and REM sleep behavioral disorders. Psychoses and hallucinations, depression and anxiety disorders, and difficulties in recognizing and experiencing emotions also impair behavior and can cause severe psychosocial problems in patients with PD. Symptoms can be present since early stages of the disease, sometimes even before the appearance of classical motor symptoms, likely in relation to dopamine depletion in basal ganglia and/or to dysfunctions of other neurotrasmitter systems, and others can develop later, in some cases in relation to dopaminergic treatment. In this paper, we review recent literature, with particular attention to the last 5 years, on the main behavioral and emotional disturbances described in PD patients as well as the hypothesized neurofunctional substrate of such impairments. Finally, we provide some suggestions on the most suitable instruments to check and assess PD-associated behavioral defects over time.

Impulse control disorders in advanced Parkinson's disease with dyskinesia: The ALTHEA study

BACKGROUND

Impulse control disorders and dyskinesia are common and disabling complications of dopaminergic treatment in Parkinson's disease. They may coexist and are possibly related. The objectives of this study were to assess the frequency and severity of impulse control disorders in Parkinson's disease patients with dyskinesia.

METHODS

The ALTHEA study enrolled 251 Parkinson's disease patients with various degrees of dyskinesia severity from 11 movement disorders centers in Italy. Each patient underwent a comprehensive assessment including Unified Dyskinesia Rating Scale and the Questionnaire for Impulsive Compulsive Disorders in Parkinson Disease-Rating Scale.

RESULTS

There was an overall 55% frequency of impulse control disorder and related behaviors (36% were clinically significant). The positive patients were younger at disease diagnosis and onset and had higher Unified Dyskinesia Rating Scale historical and total score (P = 0.001 and P = 0.02, respectively, vs negative). There was an increased frequency of clinically significant impulse control disorders in patients with severe dyskinesia (P = 0.013), a positive correlation between the questionnaire total score and dopamine agonist dose (P = 0.018), and a trend with levodopa dose.

CONCLUSIONS

More than half of Parkinson's disease patients with dyskinesia have impulse control disorders and related behaviors, which are frequently clinically significant. Dopaminergic therapy total dose is associated with their severity. Clinicians should carefully assess patients with maladaptive behaviors and dyskinesia because they do not properly evaluate their motor and nonmotor status. © 2017 International Parkinson and Movement Disorder Society.