Impulse control disorders in Parkinson's disease: A systematic review on risk factors and pathophysiology

Validation of the Italian version of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) in an Italian Parkinson's disease cohort

INTRODUCTION

Impulse control disorders (ICDs) frequently occur in Parkinson's disease (PD), and an early identification is essential to prevent severe psychosocial consequences. The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) has been developed to evaluate the severity of ICDs along with a range of impulsive-compulsive behaviors (ICBs) in PD; however, its Italian version has not yet been validated.

METHODS

One hundred consecutive outpatients with PD were administered an Italian version of the QUIP-RS and a brief neuropsychological assessment to evaluate global cognitive status and scales to measure depression, apathy and impulsive disorders. We evaluated the internal consistency, convergent and divergent validity, and factorial structure of QUIP-RS. We also explored the possible association between QUIP-RS scores and clinical factors and dopaminergic medication.

RESULTS

Subsyndromal ICDs manifestations were observed in 54% of the patients, and one in four (22%) reported two or more ICDs or related behaviors. The QUIP-RS demonstrated good internal consistency (Cronbach's alpha = 0.806) and construct validity, and its factorial structure reflected different ICDs and ICBs domains. No association emerged between QUIP-RS scores and the clinical aspects of PD and dopaminergic medication.

CONCLUSION

We provided, for the first time, an Italian translation of the QUIP-RS and demonstrated its feasibility in clinical and research settings. Severity of ICDs was independent of clinical factors and dopaminergic medication, underlining the need to adopt a broader perspective on their etiopathology in PD.

Impulse Control Disorders in Parkinson's Disease: An Overview of Risk Factors, Pathogenesis and Pharmacological Management

Impulse control disorders in Parkinson's disease are relatively common drug-induced addictive behaviours that are usually triggered by the dopamine agonists pramipexole, ropinirole and rotigotine. This narrative review aimed to provide a comprehensive overview of the current knowledge of impulse control disorders in Parkinson's disease. We summarised the prevalence, clinical features, risk factors and potential underlying mechanisms of impulse control disorders in Parkinson's disease. Moreover, recent advances in behavioural and imaging characteristics and management strategies are discussed. Early detection as well as a tailored multidisciplinary approach, which typically includes careful adjustment of the dopaminergic therapy and the treatment of associated neuropsychiatric symptoms, are necessary. In some cases, a continuous delivery of levodopa via a pump or the dopamine D1 receptor agonist, apomorphine, can be considered. In selected patients without cognitive or speech impairment, deep brain stimulation of the subthalamic nucleus can also improve addictions. Finding the right balance of tapering dopaminergic dose (usually dopamine agonists) without worsening motor symptoms is essential for a beneficial long-term outcome.

Hypersexuality in neurological disorders: A systematic review

BACKGROUND

Hypersexuality (HS) accompanying neurological conditions remains poorly characterized despite profound psychosocial impacts. Objective We aimed to systematically review the literature on HS in patients with neurological disorders. Study selection and analysis We conducted a systematic review to identify studies that reported HS in neurological disorders. HS was defined as a condition characterized by excessive and persistent preoccupation with sexual thoughts, urges, and behaviors that cause significant distress or impairment in personal, social, or occupational functioning. Data on demographics, assessment techniques, associated elements, phenotypic manifestations, and management strategies were also extracted. Findings The final analysis included 79 studies on HS, encompassing 32 662 patients across 81 cohorts with neurological disorders. Parkinson's disease was the most frequently studied condition (55.6%), followed by various types of dementia (12.7%). Questionnaires were the most common assessment approach for evaluating HS, although the techniques varied substantially. Alterations in the dopaminergic pathways have emerged as contributing mechanisms based on the effects of medication cessation. However, standardized treatment protocols still need to be improved, with significant heterogeneity in documented approaches. Critical deficiencies include risks of selection bias in participant sampling, uncontrolled residual confounding factors, and lack of blinded evaluations of reported outcomes. Conclusions and clinical implications Despite growth in the last decade, research on HS remains limited across neurological conditions, with lingering quality and methodological standardization deficits. Key priorities include advancing assessment tools, elucidating the underlying neurobiology, and formulating management guidelines.

PROSPERO REGISTRATION NUMBER

CRD42017036478.

Morphometric alterations of the mesocorticolimbic network in Parkinson's disease with impulse control disorders

Impulse control disorders (ICDs) are a group of non-motor symptoms of Parkinson disease (PD) leading to significant psychosocial detrimental outcome. The mesocorticolimbic network plays a distinctive role in reward learning and executive decision making and has been suggested to be involved in ICDs in PD. To study morphometric changes of the mesocorticolimbic network in PD with ICD. A total of 18 patients of PD with ICD (PD + ICD), 19 patients of PD without ICD (PD - ICD) and 19 healthy controls (HC) were included in the study. ICDs were diagnosed using Questionnaire for Impulsive-Compulsive Disorders in PD-Rating Scale (QUIP-RS). MRI was done using a 3T scanner and assessment of cortical thickness and subcortical volumes were done using FreeSurfer. Brain regions known to be part of the mesocorticolimbic network were extracted and included for statistical analysis. There was no difference between PD + ICD and PD - ICD with regard to duration of illness or total dopaminergic medication. In comparison to HC, patients with PD + ICD demonstrated atrophy of the left frontal pole, and this atrophy neared significance in comparison to PD - ICD. The QUIP-RS had a negative correlation with left caudate volume in PD + ICD. The PD + ICD group showed distinct morphometric changes in regions involved in the mesocorticolimbic system which may contribute to the presence of ICD.

The Role of Telemedicine in the Treatment of Cognitive and Psychological Disorders in Parkinson’s Disease: An Overview

Background: This literature review evaluates the use and efficacy of telemedicine in cognitive and psychological treatment in Parkinson’s disease. Methods: Studies performed between 2016 and 2021 that fulfilled inclusion criteria were selected from PubMed, Scopus, Cochrane, and Web of Science databases. All articles were evaluated by title, abstract, and text. All studies that examined the cognitive and psychological/psychotherapy treatment of patients with Parkinson’s disease by telemedicine were included. Results: Telehealth improved cognitive status and emotional/behavioral disorders in this population, and had positive effects on the patients’ and caregivers’ quality of life. Conclusions: Our literature review supports the development and efficacy of cognitive and psychological treatment with telemedicine, but the methodology of the study must be reviewed considering its limitations so as to highlight the benefits and risks of treatment via telemedicine.

Hypersexuality as a tip of the iceberg of a primary psychopathology: a joined position statement of the Italian Society of Andrology and Sexual Medicine (SIAMS) and of the Italian Society of Psychopathology (SOPSI)

In the last years, hypersexual behavior has been broadly scientifically studied. The interest in this topic, belonging to psycho-sexology and sexual medicine, has been due to its still unclear aetiology, nature, and its manifestation in relationship with several organic and psychopathological conditions. So, the specialist (the psychologist, psychiatrist, endocrinologist, neurologist) may encounter some difficulties in diagnosing and managing this symptom. The first main objective of this position statement, which has been developed in collaboration between the Italian Society of Andrology and Sexual Medicine (SIAMS) and the Italian Society of Psychopathology (SOPSI) is to give to the reader evidence about the necessity to consider hypersexuality as a symptom related to another underlying condition. Following this consideration, the second main objective is to give specific statements, for the biopsychosocial assessment and the diagnosis of hypersexual behavior, developed on the basis of the most recent literature evidence. To develop a psycho-pharmacological treatment tailored on patients' needs, our suggestion is to assess the presence of specific comorbid psychopathological and organic conditions, and the impact of pharmacological treatments on the presence of an excess of sexual behavior. Finally, a suggestion of a standardized psychometric evaluation of hypersexuality will be given.

Impulse control disorders associated with dopaminergic drugs: A disproportionality analysis using vigibase

BACKGROUND

Dopamine receptor agonist drugs, which are used, for example, to treat Parkinson's disease (PD), increase the risk for impulse control disorders (ICDs), potentially resulting in devastating psychosocial consequences. It is unknown whether other drugs with dopaminergic properties also increase the risk for ICDs. This study assesses the disproportionality of reporting ICDs between drugs with dopaminergic properties and selected non-dopaminergic drugs.

METHODS

A case/non-case disproportionality analysis was performed, using data from VigiBase (1968-2020). Reports on ICDs as suspected adverse drug reactions (ADRs) were cases (n=852), and those with ADRs other than ICDs were non-cases (n=281,720). Relative reporting frequencies were expressed as adjusted reporting odds ratios (aRORs). Within the dopamine receptor agonists, the relationship between reporting odds ratios and dopamine receptor occupancy was explored.

RESULTS

A high disproportionality was found for reporting ICDs for all dopaminergic drugs (aROR 20.4 [95% CI 17.4-24.1]) compared to non-dopaminergic drugs. In pharmacotherapeutic subgroups, a high disproportionality was found for primary dopaminergic agents used in PD (aROR 52.1 [95% CI 44.1-61.5]), and to a lesser extent for ADHD psychostimulants and antidepressants (aROR 5.8 [95% 4.1-8.3] and aROR 3.9 [95% CI 2.9-5.6], respectively). There was no difference in reporting by consumers and healthcare professionals. The highest disproportionality was found for the dopamine receptor agonists pramipexole and ropinirole.

CONCLUSIONS

A signal of disproportion in ICD occurrence was found among all investigated drugs with dopaminergic properties, highlighting the importance of counselling and monitoring for ICDs when prescribing dopaminergic drugs.

Impulse control disorders, dopamine dysregulation syndrome and sex dysfunction in Parkinson's disease

Hypersexuality (HS), characterized by an aberrant, compulsive and inappropriate sexual drive, is an underreported and undermanaged complication of the treatment with dopamine agonists in patients with Parkinson's disease (PD). HS is part of the spectrum of impulse control disorders (ICDs). The failure to control these addictive behaviors is distressing for the patient and it is associated with important consequences. Reports of the prevalence of HS showed different results, due to the lack of standardized diagnostic criteria, but also due to the embarrassment or guilt feelings that patients experience regarding their sexual behaviors. Overall, it is considered that HS may occur in 1.92-22.8% of PD patients and the main risk factors involved could be male sex and genetic susceptibility. The pathophysiology of HS is unknown, but several degenerative mechanisms were proposed, involving dopaminergic, serotoninergic and noradrenergic pathways in cerebral regions responsive for planning and rewarding. There are no standardized tools for the assessment of HS in PD patients; however, several scales and questionnaires were developed with the aim of screening and rating the severity of ICDs, including HS. The management of HS is challenging. Discontinuation or reducing the dopaminergic treatment was effective in some cases, but it might lead to worsening of the motor function. A multidisciplinary approach is mandatory to manage the other associated aspects, such as psychological and social consequences of HS.

The neuropsychiatry of Parkinson's disease: advances and challenges

In people with Parkinson's disease, neuropsychiatric signs and symptoms are common throughout the disease course. These symptoms can be disabling and as clinically relevant as motor symptoms, and their presentation can be similar to, or distinct from, their counterparts in the general population. Correlates and risk factors for developing neuropsychiatric signs and symptoms include demographic, clinical, and psychosocial characteristics. The underlying neurobiology of these presentations is complex and not well understood, with the strongest evidence for neuropathological changes associated with Parkinson's disease, mechanisms linked to dopaminergic therapy, and effects not specific to Parkinson's disease. Assessment instruments and formal diagnostic criteria exist, but there is little routine screening of these signs and symptoms in clinical practice. Mounting evidence supports a range of pharmacological and non-pharmacological interventions, but relatively few efficacious treatment options exist. Optimising the management of neuropsychiatric presentations in people with Parkinson's disease will require additional research, raised awareness, specialised training, and development of innovative models of care.

Genetic Markers as Risk Factors for the Development of Impulsive-Compulsive Behaviors in Patients with Parkinson's Disease Receiving Dopaminergic Therapy

Impulsive–compulsive and related behavioral disorders (ICD) are drug-induced non-motor symptoms of Parkinson’s disease (PD). Recently research has focused on evaluating whether ICD could be predicted and managed using a pharmacogenetic approach based on dopaminergic therapies, which are the main risk factors. The aim of our study was to evaluate the role of candidate genes such as DBH, DRD2, MAOA, BDNF, COMT, SLC6A4, SLC6A3, ACE, DRD1 gene polymorphisms in the pathogenesis of ICD in PD. We compared patients with PD and ICD (n = 49), patients with PD without ICD (n = 36) and a healthy control group (n = 365). ICD was diagnosed using the QUIP questionnaires and specific diagnostic criteria for subtypes of ICD. Genotyping was conducted using a number of PCR techniques and SNaPshot. Statistical analysis was performed using WinPepi and APSampler v3.6 software. PCA testing was conducted using RStudio software v1.4.1106-5. The following substitutions showed statistically significant correlations with PD and ICD: DBH (rs2097629, rs1611115), DRD2 (rs6275, rs12364283, rs1076560), ACE (rs4646994), DRD1 (rs686), BDNF (rs6265), these associations are novel in Russian PD patients. Our findings suggest that polymorphisms in DBH, BDNF, DRD2, ACE genes in Russian subjects are associated with an increased risk of ICD development.

Analysis of Impulse Control Disorders (ICDs) and Factors Associated with Their Development in a Parkinson's Disease Population

Parkinson's Disease (PD) is a neurodegenerative disease in which non-motor symptoms may appear before motor phenomena, which include Impulse Control Disorders (ICDs). The objective of this study is to identify factors associated with the development of ICDs in PD. An analytical, cross-sectional study was conducted using clinical records from patients diagnosed with PD, both genders, from 40 to 80 years old. Clinical and demographic data were collected: 181 patients were recruited; 80 of them showed PD and ICDs, and they constituted the study group, whereas 101 patients with PD without ICDs constituted the control reference group. The duration of PD was longer in the group with ICDs (p < 0.008), and all patients showed at least one ICD: binge eating (61.29%), compulsive shopping (48.75%), hypersexuality (23.75%), gambling behavior (8.75%), and punding (3.75%). After logistic regression analysis, only the use of dopamine agonists remained associated with ICDs (p < 0.001), and the tremorgenic form was suggested to be a protective factor (p < 0.001). Positive associations were observed between the rigid-akinetic form and compulsive shopping (p < 0.007), between male and hypersexuality (p < 0.018), and between dopamine agonists and compulsive shopping (p < 0.004), and negative associations were observed between motor fluctuations and compulsive shopping (p < 0.031), between Deep Brain Stimulation and binge eating (p < 0.046), and between levodopa consumption and binge eating (p < 0.045). Binge eating, compulsive shopping, and hypersexuality were the most frequent ICDs. Complex forms and motor complications of PD were associated with the development of ICDs.

Central Pain in Parkinson's Disease: Behavioral and Cognitive Characteristics

Introduction

Pain is a major nonmotor symptom of Parkinson's disease (PD), and central parkinsonian pain is the core feature of the putative Park pain subtype of PD. This study aimed to explore the cognitive and behavioral profile of PD patients with central parkinsonian pain. Material and Methods. A structured interview was used to identify and characterize pain in a cohort of 260 consecutive PD patients. The Ford classification of pain was applied. The Dementia Rating Scale-2 (DRS-2) and the Impulse Control Disorders in Parkinson's Disease Short Form (QUIP-S) were administered, and patients' smoking habits were recorded. The Unified Parkinson's Disease Rating Scale (UPDRS) was used to assess motor and nonmotor symptoms in off and on conditions.

Results

One hundred and eighty-eight patients (68%) reported pain; and in 41 (22%) of them, the pain was classified as central parkinsonian pain. PD patients with central parkinsonian pain had better cognitive performance in DRS-2 Initiation/Perseveration and Conceptualization subscales but reported more other compulsive behaviors (e.g., hobbyism, punding, and walkabout) and had more current smoking habits than those without pain or with non-central parkinsonian pain. Multiple logistic regression analyses revealed that the DRS-2 Conceptualization subscale, other compulsive behaviors, and smoking habits remained statistically associated with central parkinsonian pain even when other significant covariates were considered. Only patients with pain, regardless of type, had a gambling disorder. Discussion. The study results provide further evidence that pain revealed that patients with central parkinsonian pain are more likely to present compulsive or addictive behaviors, despite having more preserved cognitive performance. Patients with central parkinsonian pain appear to have a distinct phenotype of PD.

Effects of domotics on cognitive, social and personal functioning in patients with Parkinson's disease: A pilot study

Home automation (HA) is either a "smart" house or a supportive environment, which enables the patients to regain an active role in daily life. HA could allow people affected by Parkinson Disease (PD) to better manage their daily lives. This study aims to evaluate the effects of domotics on quality of life, and personal/social autonomy in PD patients. We enrolled 40 with PD undergoing neurorehabilitation, who were randomized into either the control (CG) or the experimental group (EG). Two different rehabilitative approaches were used: the CG was submitted to a traditional training, whilst the EG underwent HA training, in which the activities were carried out through the use of assistive technologies. In both the training, the exercises were performed in small samples of 3-5 patients. Results showed that both CG and EG had a significant improvement in global cognitive functioning, executive functions, and instrumental autonomy. However, only in the EG, we observed a significant increase in social adaptation, activities of daily living and quality of life. This pilot study suggests that HA training could be a useful tool for the rehabilitation of patients with PD, improving social and cognitive functioning, personal autonomy and quality of life.

Polymorphisms of Dopamine Receptor Genes and Parkinson's Disease: Clinical Relevance and Future Perspectives

Parkinson’s disease (PD) is a neurodegenerative disease caused by loss of dopaminergic neurons in the midbrain. PD is clinically characterized by a variety of motor and nonmotor symptoms, and treatment relies on dopaminergic replacement. Beyond a common pathological hallmark, PD patients may present differences in both clinical progression and response to drug therapy that are partly affected by genetic factors. Despite extensive knowledge on genetic variability of dopaminergic receptors (DR), few studies have addressed their relevance as possible influencers of clinical heterogeneity in PD patients. In this review, we summarized available evidence regarding the role of genetic polymorphisms in DR as possible determinants of PD development, progression and treatment response. Moreover, we examined the role of DR in the modulation of peripheral immunity, in light of the emerging role of the peripheral immune system in PD pathophysiology. A better understanding of all these aspects represents an important step towards the development of precise and personalized disease-modifying therapies for PD.

Non-invasive brain stimulation targets and approaches to modulate gambling-related decisions: A systematic review

INTRODUCTION

Despite intense neuroscience research on the neurobiological underpinnings of Gambling Disorder (GD) and gambling-related decision-making, effective treatments targeting these dysfunctions are still lacking. Non Invasive Brain Stimulation (NIBS) techniques, such as transcranial Direct Current Stimulation (tDCS) and Transcranial Magnetic Stimulation (TMS), selectively modulate activity of brain circuits and have the potential to reverse alterations sustaining GD symptoms. Therefore, the aim of this systematic review was to determine the impact of different NIBS interventions on gambling-related decision processes.

METHODS

We conducted a comprehensive and translational search in three online databases (MEDLINE via PubMed, Scopus, Web of Science), in accordance with the PRISMA guidelines. We included studies applying neuromodulation (TMS, tDCS) techniques in GD patients or assessing gambling-related decision-making in healthy subjects. In addition, we explored the potential impact of NIBS in drug-induced GD (e.g., Parkinson's Disease).

RESULTS

Twenty-seven studies have been included. We summarized results to detect the impact of different targets and stimulation/inhibition protocols in terms of gambling-related decision-making. The majority of both tDCS and TMS studies targeted the dorsolateral prefrontal cortex. Although heterogeneous in protocols and parameters, results from tDCS and TMS studies converge in indicating that the stimulation (instead of inhibition) of prefrontal regions could be beneficial to contrast dysfunctional gambling-related decision processes.

CONCLUSION

NIBS interventions show promise to be further tested in controlled clinical settings for the treatment of behavioral addictions. Further studies are also necessary to investigate connectivity changes and laterality issues (unilateral versus bilateral; left versus right) of NIBS application in GD.

Sexual Dysfunction in Parkinson Disease: A Multicenter Italian Cross-sectional Study on a Still Overlooked Problem

BACKGROUND

Prevalence rates of sexual dysfunction (SD) in Parkinson's disease (PD) are likely to be underestimated and their etiology is still unknown. More understanding of this issue is needed.

AIM

To investigate prevalence of SD and its variables, including gender differences, in a sample of PD patients.

METHODS

This multicenter observational study included 203 patients (113 males and 90 females) affected by PD (diagnosed according to UK Parkinson's Disease Society Brain Bank clinical diagnostic criteria 28), and living in 3 different Italian regions. Patients were evaluated using a semi-structured interview (a 40-item ad hoc questionnaire, developed by the authors to investigate patient's 3 main life areas: sociodemographic information, illness perception, and sexuality) and specific standardized scales to investigate SD, as well as by means of tools to assess their motor impairment, daily life activities, and disease-related caregiver burden (CBI).

MAIN OUTCOME MEASURES

The International Index of Erectile Function and the Female Sexual Function Index.

RESULTS

Sexual dysfunction was observed in about 68% of men, and in around 53% of women loss of libido being the main sexual concern in both sexes. Men were significantly more affected by SD than women (χ² (1) = 4.34, P-value = .037), but no difference in the severity of the dysfunction emerged between genders. Around 85% of PD patients had a stable couple relationship, and about 40% were satisfied with such a relationship. However, about 57% of the patients stated that the disease affected their sexual life, especially due to reduced sexual desire, and the frequency of sexual intercourses. Moreover, significant differences between subjects with SD and subjects without SD were found in UPDRS (I-II-III domains), in Hamilton Depression Rating Scale and CBI scores.

CLINICAL IMPLICATIONS

Clinicians dealing with PD should pay more attention to sexual issues, as discussing and treating sexual problems enters the framework of a holistic approach, which is mandatory in chronic illness.

STRENGTHS & LIMITATIONS

The major strengths of this study include the multicenter nature of the study, to overcome single-center methodological bias. The main limitation is the relatively small sample size, and the absence of a control group, even if there are growing literature data on sexuality and aging supporting our findings.

CONCLUSION

SD is a highly prevalent and devastating problem in patients affected by PD, negatively affecting their quality of life. Raciti L, De Cola MC, Ortelli P, et al. Sexual Dysfunction in Parkinson Disease: A Multicenter Italian Cross-sectional Study on a Still Overlooked Problem. J Sex Med 2020;17:1914-1925.

Understanding the role of social cognition in neurodegenerative Disease: A scoping review on an overlooked problem

Social cognition (SC) is the set of socio-cognitive processes that guide automatic and voluntary behaviors by modulating behavioral responses, it includes both cognitive (Theory of the mind - ToM) and affective aspects (Empathy). SC also includes representations of internal somatic states, self-knowledge, perception of others, communication with others and interpersonal motivations. SC is relevant in daily life and reflects the neural complexity of social processing. The purpose of this scoping review is to evaluate the role of SC in neurological disorders, also considering the pathophysiological mechanisms underlying SC and potential assessment tools. The included studies were carried out between 2010 and 2019 and were found on PubMed, Scopus, Cochrane, and Web of Sciences databases, using the combined terms "social cognition"; "dementia"; "multiple sclerosis"; "parkinson", "amyotrophic lateral sclerosis", "neurodegenerative disease". Our review has shown that different SC domains are affected by several neurological conditions, with regards to dementia and amyotrophic lateral sclerosis. Further studies are needed to investigate the association between cognitive and social deficits, for a better management of patients with neurological disorders.

Computer assisted cognitive rehabilitation improves visuospatial and executive functions in Parkinson's disease: Preliminary results

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disease due to dopamine deficiency in the basal ganglia, leading to motor symptoms such as bradykinesia, tremor, stiffness, and postural instability. This disease may also be associated with a broad spectrum of non-motor symptoms. More than 24% of patients with PD have one or more cognitive symptoms.

OBJECTIVE

To evaluate the effects of computer-assisted cognitive rehabilitation (CACR) in Parkinson's disease (PD).

METHODS

Sixty patients with PD were enrolled in this study and were randomly divided into control group (CG) and experimental group (EG). Each participant was evaluated at the beginning (T0) and at the end of training (T1). The CG underwent standard cognitive training (SCT) while EG performed CACR using the ERICA platform, aimed at improving several cognitive domains. In both the group, each training consisted of 3 sessions a week, each of these lasting sixty minutes, for eight weeks.

RESULTS

Although both the groups had significant improvement after CR, we observed more significant changes in the EG, especially concerning attention, orientation and visual-spatial domains.

CONCLUSIONS

Our data demonstrate that CACR is more effective than SCT in improving visual-spatial and executive deficits, in patients affected by PD.

Trait Impulsivity Is Independent of Mild Cognitive Impairment in a Parkinson's Disease Cohort

Introduction

Patients with Parkinson's disease (PD) commonly experience cognitive deficits and some also develop impulse control disorders (ICDs); however, the relationship between impulsivity and cognitive dysfunction remains unclear. This study investigated whether trait impulsivity associates with mild cognitive impairment (MCI), or is altered in a PD patient cohort with MCI.

Methods

A total of 302 patients with idiopathic PD were recruited sequentially from three Australian Movement Disorder clinics. Based on cognitive scores, participants were divided into two groups, one defined as having mild cognitive impairment (PD-MCI; n = 113) and the other with normal cognitive function (PD-C; n = 189). Trait impulsivity was evaluated using the Barrett Impulsiveness Scale 11 (BIS-11). Total impulsivity scores, as well as subscale scores, were compared between PD-C and PD-MCI groups.

Results

The PD-MCI cohort had significantly lower scores in all cognitive domains, and mirrored expected clinical differences in medication, motor symptoms, and disease duration, when compared to the PD-C cohort. Self-reported impulsivity was not significantly different between groups, nor was there a difference within first-order subscale scores: attention (p=0.137), cognitive instability (p=0.787), self-control (p=0.503), cognitive complexity (p=0.157), motor impulsivity (p=0.559), or perseverance (p=0.734) between the PD-MCI and PD-C groups.

Conclusions

These findings suggest that impulsive traits and behaviors are independent of changes in cognitive state and are not altered in PD patients with mild cognitive impairment.