Affective symptoms and cognitive functions in Parkinson's disease

Exploring the Neuropsychological Correlates of Swallowing Disorders in People with Parkinson's Disease: a Cross-Sectional Study

Around 80% of persons with Parkinson's disease (PD) present symptoms of dysphagia. Although cognitive impairment may contribute to dysphagia, few studies have investigated the association between the PD neuropsychological profile and objective measures of swallowing dysfunction. Since the swallowing function comprises involuntary but also voluntary actions, we hypothesize that specific measures of attention and executive functions can be underlined in PD-related dysphagia. Therefore, the aim of this study was to extensively investigate the correlation and the relationship between attentive and executive functions and safety/efficiency of pharyngeal phase of swallowing in people with PD. All participants received a fiberoptic endoscopic evaluation of swallowing and were evaluated using the Penetration Aspiration Scale (PAS); the Yale Pharyngeal Residue Severity Rating Scale (IT-YPRSRS), and the Functional Oral Intake Scale (FOIS-IT). Participants also underwent a neuropsychological assessment covering global cognitive status, attention, and frontal executive functions. Correlations and associations between neuropsychological measures and swallowing components were calculated. Twenty-one participants with PD (mean age 69.38 ± 6.58 years, mean disease duration 8.38 ± 5.31 years; mean MDS-UPDRS III 43.95 ± 24.18) completed all evaluations. The most significant correlations were found between attentive functions (i.e., Stroop Time), and executive functions (i.e., Raven's Progressive Matrices, Digit Backward and Semantic Fluency), and FOIS-IT, PAS, and IT-YPRSRS sinuses and valleculae. These associations were not influenced by disease duration. These results suggest that a dysfunction to attentional processes and/or to executive functions can contribute to penetration and the presence of pharyngeal residue in participants with middle-stage PD.

Relationships between physical activities performed under free-living conditions and non-motor symptoms in people with Parkinson's: A systematic review and meta-analysis

BACKGROUND

Physical activities performed under free-living conditions that are unsupervised in the home or community have the potential to modulate non-motor symptoms in people with Parkinson's disease.

OBJECTIVE

This systematic review investigates the relationships between physical activities performed in free-living conditions and non-motor symptoms in people with Parkinson's disease: cognition, anxiety, apathy, depression, sleep disturbances, fatigue, and pain.

DATA SOURCES

A database search was performed on Scopus, Web of Science, Ovid (PsycINFO), CINAHL, PubMed, and ProQuest (Health and Medicine).

REVIEW METHODS

Observational studies published from 2000 to 2024 that examined the relationships between physical activity and non-motor symptoms were included. The methodological quality of reports was evaluated using critical appraisal checklists appropriate to the study design. Where appropriate, a meta-analysis was conducted to combine data from the included articles.

RESULTS

A total of 14 articles met the criteria and used various tools to evaluate non-motor symptoms and physical activity. Meta-analyses showed that people with Parkinson's who are more physically active have better global cognition [β ranged from 0.12 to 0.28; p = 0.00-0.02] and less affective disorders [β -0.20, p = 0.00]. Increased physical activity levels were also associated with better sleep quality (n = 1) and less chronic pain (n = 1). The overall methodological quality of the included articles was considered high.

CONCLUSION

Engagement in increased levels of physical activities performed under free-living conditions is associated with better cognition and less anxiety, apathy, and depression in people with Parkinson's disease.

Facial expressions and identities recognition in Parkinson disease

Parkinson's Disease (PD) is associated with motor and non-motor symptoms. Among the latter are deficits in matching, identification, and recognition of emotional facial expressions. On one hand, this deficit has been attributed to a dysfunction in emotion processing. Another explanation (which does not exclude the former) links this deficit with reduced facial expressiveness in these patients, which prevents them from properly understanding or embodying emotions. To disentangle the specific contribution of emotion comprehension and that of facial expression processing in PD's observed deficit with emotions we performed two experiments on non-emotional facial expressions. In Experiment 1, a group of PD patients and a group of Healthy Controls (HC) underwent a task of non-emotional expression recognition in faces of different identity and a task of identity recognition in faces with different expression. No differences were observed between the two groups in accuracies. In Experiment 2, PD patients and Healthy Controls underwent a task where they had to recognize the identity of faces encoded through a non-emotional facial expression, through a rigid head movement, or as neutral. Again, no group differences were observed. In none of the two experiments hypomimia scores had a specific effect on expression processing. We conclude that in PD patients the observed impairment with emotional expressions is likely due to a specific deficit for emotions to a greater extent than for facial expressivity processing.

Interoceptive technologies for psychiatric interventions: From diagnosis to clinical applications

Interoception-the perception of internal bodily signals-has emerged as an area of interest due to its implications in emotion and the prevalence of dysfunctional interoceptive processes across psychopathological conditions. Despite the importance of interoception in cognitive neuroscience and psychiatry, its experimental manipulation remains technically challenging. This is due to the invasive nature of existing methods, the limitation of self-report and unimodal measures of interoception, and the absence of standardized approaches across disparate fields. This article integrates diverse research efforts from psychology, physiology, psychiatry, and engineering to address this oversight. Following a general introduction to the neurophysiology of interoception as hierarchical predictive processing, we review the existing paradigms for manipulating interoception (e.g., interoceptive modulation), their underlying mechanisms (e.g., interoceptive conditioning), and clinical applications (e.g., interoceptive exposure). We suggest a classification for interoceptive technologies and discuss their potential for diagnosing and treating mental health disorders. Despite promising results, considerable work is still needed to develop standardized, validated measures of interoceptive function across domains and before these technologies can translate safely and effectively to clinical settings.

Disturbance of functional brain networks and cognitive decline in Parkinson's disease: Severe cerebral small vessel disease aggravates this relationship

INTRODUCTION

Several studies have identified a relationship between functional brain network disturbance and cognitive decline in people with Parkinson's disease (PwP); however, few studies have explored whether cerebral small vessel disease (CSVD) burden modifies this relationship. This study aimed to investigate the potential moderating effect of CSVD on the relationship between functional brain network disturbance and cognitive decline in PwP.

METHODS

We prospectively recruited 61 PwP from Beijing Tiantan Hospital between October 2021 to September 2022. The Montreal Cognitive Assessment (MoCA) score was used to assess cognition. CSVD imaging markers were evaluated following the STandards for ReportIng Vascular changes on nEuroimaging instructions, and the CSVD burden score was calculated. The functional connectivity indicator was obtained and calculated using quantitative electroencephalography examination. The moderating effect of CSVD burden on the relationship between functional brain network disturbance and cognitive decline was examined using hierarchical linear regression.

RESULTS

Forty-six of 61 (75.4%) PwP had cognitive impairment. Higher global weighted phase lag index (wPLI) values in beta1 bands were significantly associated with lower adjusted MoCA scores. CSVD burden aggravated the effect of the global wPLI in beta1 bands on adjusted MoCA scores. This effect was reinforced by the high level of CSVD burden.

CONCLUSIONS

Higher wPLI indicates a possible pathological activation of functional brain networks that are associated with cognitive decline in PwP, and the high level of CSVD burden aggravates this relationship.

Depression After Parkinson's Disease: Treated Differently or Not At All?

Depression is a common, potentially debilitating non-motor symptom of Parkinson's disease which may manifest at any time and can respond to treatment. Although depression is a known primary mediator of health-related quality of life, it is currently unknown whether the timing of depression diagnosis relative to PD diagnosis affects receipt of depression treatment. Electronic health record data were examined to explore differences in depression treatment among patients diagnosed with depression before or after PD diagnosis. Compared to PD patients diagnosed with depression prior to PD, those diagnosed with depression following PD are less likely to receive any treatment, either pharmacologic or non-pharmacologic, indicating a temporal association between the time of PD diagnosis and receipt of depression treatment. This highlights a potentially substantial treatment gap, despite the existence of efficacious treatment. Diagnosis with PD appears to alter depression treatment and further research is warranted to determine potential causes and effective interventions.

Depression differentially affects patient and caregiver perceptions of neuropsychiatric symptoms in Parkinson's disease

OBJECTIVE

The aims of this study were twofold. First, we examined the relationship between patient and caregiver ratings of neuropsychiatric symptoms in Parkinson's disease (PD). Second, we examined if the severity of depressive symptoms affects patient and caregiver perceptions of other neuropsychiatric symptoms and contributes to discrepancies between their perceptions.

METHOD

We examined data from a retrospective clinical cohort of 209 patients with PD and their caregivers. We used intra-class correlation coefficients and the Bland Altman method to assess intra-respondent (retrospective versus current) and inter-respondent (patient versus caregiver) agreement between Frontal Systems Behavior Scales (FrSBe) subscale scores. We then used generalized estimating equation models to examine FrSBe subscale scores and the magnitude of the intra- and inter-respondent discrepancies in FrSBe subscale scores, as a function of Beck Depression Inventory-2^nd Edition scores, with patient demographic variable adjustments.

RESULTS

There was low agreement between patient and caregiver ratings on all three subscales, at both time points, and high response variability within and between raters. Patients generally reported more severe neuropsychiatric symptoms than caregivers. Depression severity predicted patients' perceptions at both time points, but was more strongly associated with current perceptions. Depression severity predicted caregivers' current perceptions only. The inter-respondent discrepancy in perceived apathy and disinhibition, but not executive dysfunction, increased as a function of depression severity.

CONCLUSIONS

There are differences in how patients with PD and caregivers perceive neuropsychiatric behaviors and the extent to which depressive symptoms influence their perceptions. Shared neuropathology and negative response biases likely contribute to these relationships.

Cognitive dysfunction and neuropsychiatric aspects of Parkinson's disease

Movement abnormalities, by definition, and cognitive changes, to varying extents, affect every patient with Parkinson's disease (PD) and are attributed to the underlying neurodegenerative disease. Various psychiatric disorders occur in most patients at some point over the course of PD, including in the prodromal phase. Even though psychiatric disturbances tend to aggravate motor and cognitive deficits, they are under-recognized and under-treated, and the role of the underlying neurological disease is often minimized. To provide an integrated approach to understanding neuropsychiatric aspects of PD, this chapter reviews how cognitive changes in PD relate to the common psychiatric disturbances in PD along with the prevalence, phenomenology, pathophysiology, and treatment of each.

Influence of radial optic flow stimulation on static postural balance in Parkinson's disease: A preliminary study

The role of optic flow in the control of balance in persons with Parkinson's disease (PD) has yet to be studied. Since basal ganglia are understood to have a role in controlling ocular fixation, we have hypothesized that persons with PD would exhibit impaired performance in fixation tasks, i.e., altered postural balance due to the possible relationships between postural disorders and visual perception. The aim of this preliminary study was to investigate how people affected by PD respond to optic flow stimuli presented with radial expanding motion, with the intention to see how the stimulation of different retinal portions may alter the static postural sway. We measured the body sway using center of pressure parameters recorded from two force platforms during the presentation of the foveal, peripheral and full field radial optic flow stimuli. Persons with PD had different visual responses in terms of fixational eye movement characteristics, with greater postural alteration in the sway area and in the medio-lateral direction than the age-matched control group. Balance impairment in the medio-lateral oscillation is often observed in persons with atypical Parkinsonism, but not in Parkinson's disease. Persons with PD are more dependent on visual feedback with respect to age-matched control subjects, and this could be due to their impaired peripheral kinesthetic feedback. Visual stimulation of standing posture would provide reliable signs in the differential diagnosis of Parkinsonism.

Subclinical depression and anxiety impact verbal memory functioning differently in men and women -an fMRI study

BACKGROUND

Depressive symptoms are known to affect memory efficiency in various populations. More specifically, several studies conducted in patients suffering from schizophrenia have indicated that memory efficiency is affected by depressed mood in female patients and by anxiety in male patients. We investigated, using neuroimaging techniques, whether similar gender-specific associations with subclinical depression and anxiety could be observed in a non-clinical sample.

METHOD

Forty-five healthy Spanish-speaking individuals (23 females) were administered a verbal memory task. Lists of high- and low-frequency words were presented. Immediate free recall was requested after the learning of each list, and a yes/no recognition task was completed during the acquisition of the fMRI data.

RESULTS

Regression analyses revealed that higher depression scores in women, and higher anxiety scores in men, were associated with poorer recall. In women, higher depression scores were further associated with decreased cerebral activity in the right temporoparietal junction, left inferior occipitotemporal gyrus, bilateral thalamus, and left anterior cingulate during correct recognition of target words. In men, anxiety scores were not associated with any cerebral activity.

CONCLUSIONS

Subclinical depression in women appears to affect memory efficiency by impacting cerebral regions specifically recruited for the cognitive demands of the task, as well as cerebral regions more generally involved in arousal, decision-making, and emotional regulation. Anxiety in men might impact the encoding memory processes. The results, although preliminary, suggest that gender differences may need to be taken into account when developing strategies for the cognitive and pharmacological remediation of memory impairment.

Theta and gamma connectivity is linked with affective and cognitive symptoms in Parkinson's disease

BACKGROUND

The progression of Parkinson's disease (PD) can often exacerbate symptoms of depression, anxiety, and/or cognitive impairment. In this study, we explore the possibility that multiple brain network responses are associated with symptoms of depression, anxiety and cognitive impairment in PD. This association is likely to provide insights into a single multivariate relationship, where common affective symptoms occurring in PD cohorts are related with alterations to electrophysiological response.

METHODS

70 PD patients and 21 healthy age-matched controls (HC) participated in a high-density electroencephalography (EEG) study. Functional connectivity differences between PD and HC groups of oscillatory activity at rest and during completion of an emotion-cognition task were examined to identify key brain oscillatory activities. A canonical correlation analysis (CCA) was applied to identify a putative multivariate relationship between connectivity patterns and affective symptoms in PD groups.

RESULTS

A CCA analysis identified a single mode of co-variation linking theta and gamma connectivity with affective symptoms in PD groups. Increases in frontotemporal gamma, frontal and parietal theta connectivity were related with increased anxiety and cognitive impairment. Decreases in temporal region theta and frontoparietal gamma connectivity were associated with higher depression ratings and PD patient age.

LIMITATIONS

This study only reports on optimal dosage of dopaminergic treatment ('on' state) in PD and did not investigate at "off" medication".

CONCLUSIONS

Theta and gamma connectivity during rest and task-states are linked to affective and cognitive symptoms within fronto-temporo-parietal networks, suggesting a potential assessment avenue for understanding brain-behaviour associations in PD with electrophysiological task paradigms.

123I-Ioflupane dopamine transporter imaging (DaTSCAN) appearances in relation to emotional responsiveness, impulsivity and olfaction in suspected Parkinsonian syndrome

OBJECTIVE

The aim of our study was to ascertain relationships between DaTSCAN, olfactory loss, behavioural and subjective measurements of impulsivity and emotional responsiveness in patients with clinically suspected Parkinsonian syndrome (PS).

METHODS

A prospective study of 20 drug-naive patients with parkinsonism, underwent the University of Pennsylvania Smell Identification Test, impulsivity measurements and mood-state-questionnaires before visual and semi-quantitative DaTQUANT analyses. There were two subgroups: nine patients with scans without evidence of dopaminergic deficit (SWEDD - controls) and 11 patients with PS.

RESULTS

The PS group reported lower non-planning impulsivity than the SWEDD group (P = 0.039). A positive correlation was found between the non-planning impulsivity ratings and right anterior putamen/background (bck) ratio in PS group (r = 0.598, P = 0.068). Higher ratings of anger (r = 0.575, P = 0.016), fatigue (r = 0.746, P = 0.001), confusion (r = 0.561, P = 0.019) and depression were positively correlated with putamen/caudate ratios (R > L) on DaTSCAN. Higher self-reported arousal was associated with lower right putamen/caudate ratio (P = -0.581, P = 0.014). Only fatigue was positively correlated with putamen/bck (r = 0.564, P = 0.018). The degree of smell deficit correlated negatively with performance on reflection impulsivity tasks (r = -0.470, P = 0.049).

CONCLUSION

DaTSCAN appearances correlated with emotional dysfunction and self-reported impulsivity in patients with PS. Olfactory impairment was associated with increased reflection impulsivity and the age of patients. Higher DaTSCAN putamen/caudate ratios were associated with higher emotional responsiveness and higher non-planning impulsivity in PS patients. These preliminary findings may be relevant in clinical practice in differentiating PS from SWEDD and identifying susceptibility to impulse control disorder although larger studies are warranted.

Depressive symptoms effect subjective sleep quality in Chinese patients with Parkinson's disease

OBJECTIVES

The objective of this paper was aimed to estimate the influence of depressive symptoms on subjective sleep quality in Chinese PD patients.

PATIENTS AND METHODS

A sample of 491 PD patients was collected and studied in the present study. Depressive symptoms were assessed using the Hamilton Rating Scale for Depression (HAMD). PD severity was assessed using Hoehn and Yahr (H-Y) staging, and motor symptoms were measured with the Unified PD Rating Scale (UPDRS) part III. The Montreal Cognitive Assessment (MOCA) was used to evaluate the global Cognitive status and PD Sleep Scale (PDSS) was used to quantify sleep quality. Three linear regression models were built to check factors associated with caregiver burden, one for the total sample and two for subgroups stratified by the presence of cognitive disturbance.

RESULTS

In our sample, 29.9% of patients suffer from sleep disturbance. The most frequent depressive symptoms were helplessness (81.5%), depressed mood (57.8%), and general somatic symptoms (55.4%) for entire sample. Patients with cognitive disturbance (n = 274; 55.8% of sample) presented more depressive symptoms than patients without cognitive disturbance. Patients suffer poorer sleep quality when patients experience depression with cognitive disturbance. On linear regression models, the main determinants of subjective quality for the total sample were NMS-depression/anxiety/anhedonia, HAMD-anxiety/somatization, disease severity, age and HAMD-loss of weight. For patients with cognitive disturbance, the significant determinants were NMS-depression/anxiety/anhedonia, HAMD-anxiety/somatization, motor symptoms, HAMD-loss of weight and gender. For patients without cognitive disturbance, the significant determinants were NMS-depression/anxiety/anhedonia, disease severity and HAMD-anxiety/somatization.

CONCLUSION

Depressive symptoms in PD are highly associated with and are determinants of subjective sleep quality, and are more prevalent in patients with cognitive disturbance. Detailed assessment and specific interventions aimed at depression and dementia could alleviate sleep disorder.

Maladaptive avoidance patterns in Parkinson's disease are exacerbated by symptoms of depression

Parkinson's disease (PD) is a chronic, progressive neurodegenerative disorder, characterized by a loss of dopaminergic neurons in the substantia nigra pars compacta. Given that dopamine is critically involved in learning and other cognitive processes, such as working memory, dopamine loss in PD has been linked both to learning abnormalities and to cognitive dysfunction more generally in the disease. It is unclear, however, whether avoidance behavior is impacted in PD. This is significant, as this type of instrumental behavior plays an important role in both decision-making and emotional (dys) function. Consequently, the aim of the present study was to examine avoidance learning and operant extinction in PD using a computer-based task. On this task, participants control a spaceship and attempt to shoot an enemy spaceship to gain points. They also learn to hide in safe areas to protect from (i.e., avoid) aversive events (on-screen explosions and point loss). The results showed that patients with PD (N = 25) acquired an avoidance response during aversive periods to the same extent as healthy age-matched controls (N = 19); however, patients demonstrated greater hiding during safe periods not associated with aversive events, which could represent maladaptive generalization of the avoidance response. Furthermore, this impairment was more pronounced during the extinction phase, and in patients who reported higher levels of depression. These results demonstrate for the first time that PD is associated with maladaptive avoidance patterns, which could possibly contribute to the emergence of depression in the disease.

Drug Choices and Advancements for Managing Depression in Parkinson's Disease

Depression is a frequent non-motor symptom of Parkinson’s disease (PD), and may even precede the onset of motor symptoms of parkinsonism. Beyond its negative influence on mood, depression in PD is frequently associated with other neuropsychiatric symptoms and with late-stage complications such as dementia. Despite its profound impact on the quality of life and cognitive functioning in PD, depression in PD is often under-recognized and poorly treated.

Pathophysiological studies demonstrated that depression in PD is associated with global dysfunction of interactions between discrete brain areas rather than focal structural or functional abnormalities, and that it is sustained by pathological changes of several neurotransmitter/receptor complexes.

In general, all traditional antidepressants and some dopamine agonists have been found to be safe and well-tolerated to treat depressive symptoms in PD, despite initial warning on worsening of parkinsonism. Available data suggest that the time-course of response differs among antidepressants. Efficacy results from clinical trials with antidepressant in PD are, however, rather uncertain, although pooled analysis suggests a moderate benefit. Several issues may critically impact the results of clinical trials with antidepressants in PD, including the correct psychiatric diagnosis, the overlap of symptoms between depression and PD, and the selection of appropriate end-points and rating scales.

Mesenchymal stem cell transplantation and aerobic exercise for Parkinson's disease: therapeutic assets beyond the motor domain

Parkinson's disease (PD) is a very common neurodegenerative condition in which both motor and nonmotor deficits evolve throughout the course of the disease. Normally characterized as a movement disorder, PD has been broadly studied from a motor perspective. However, mild to moderate cognitive deficits began to appear in the early phases of the disease, even before motor disturbances actually manifest, and continue to progress relentlessly. These nonmotor manifestations are also a source of detriment to the patients' already strained functionality and quality of life, and pose a therapeutic challenge seeing that replacing therapies have had conflicting results. Considering that the currently approved therapies can hardly be considered curative, efforts to find therapeutic approaches with an actual disease-modifying quality and capable of addressing not only motor but also cognitive dysfunctions are clearly needed. Among possible alternatives with such attribute, mesenchymal stem cell transplantation and exercise are worth highlighting given their common neuroprotective, neuroplastic, and immunomodulatory properties. In this paper, we will summarize the existent literature on the topic, focusing on the mechanisms of action through which these two approaches might beget therapeutic benefits for PD beyond the commonly assessed motor dysfunctions, alluding, at the same time, toward a potential synergic association of both therapies as an optimized approach for PD.

Symptom Dimensions of Depression and Apathy and Their Relationship With Cognition in Parkinson's Disease

OBJECTIVES

Both depression and apathy, alone and in combination, have been shown to negatively affect cognition in patients with Parkinson's disease (PD). However, the influence of specific symptom dimensions of depression and apathy on cognition is not well understood. The current study investigated the relationship between symptom dimensions of depression and apathy, based on factors identified in Kirsch-Darrow et al. (2011), and memory and executive function in PD.

METHODS

A sample of 138 non-demented individuals with PD (mean age=64.51±7.43 years) underwent neuropsychological testing and completed the Beck Depression Inventory, 2nd Edition, and Apathy Scale. Separate hierarchical regression models examined the relationship between symptom dimensions of depression and apathy ("pure" depressive symptoms, "pure" apathy, loss of interest/pleasure [anhedonia], and somatic symptoms) and three cognitive domain composites: immediate verbal memory, delayed verbal memory, and executive function.

RESULTS

After adjusting for general cognitive status and the influence of the other symptom dimensions, "pure" depressive symptoms were negatively associated with the delayed verbal memory composite (p<.034) and somatic symptoms were positively associated with the executive function composite (p<.026). No symptom dimensions were significantly related to the immediate verbal memory composite.

CONCLUSIONS

Findings suggest that specific mood symptoms are associated with delayed verbal memory and executive function performance in non-demented patients with PD. Further research is needed to better understand possible mechanisms through which specific symptom dimensions of depression and apathy are associated with cognition in PD. (JINS, 2018, 24, 269-282).

The relation of anxiety and cognition in Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) has long been conceptualized as a motor disorder, but nonmotor symptoms also manifest in the disease and significantly reduce quality of life. Anxiety and cognitive dysfunction are prevalent nonmotor symptoms, even in early disease stages, but the relation between these symptoms remains poorly understood. We examined self-reported anxiety and neurocognitive function, indexed by measures of executive function (set-shifting and phonemic fluency), categorical fluency, and attention/working memory. We hypothesized that anxiety would correlate with cognitive performance.

METHOD

The Beck Anxiety Inventory and cognitive tests (Trail Making, Verbal Fluency, Digit Span) were administered to 77 nondemented adults with mild to moderate idiopathic PD (39 men, 38 women; Mage = 62.9 years).

RESULTS

Higher anxiety was associated with more advanced disease stage and severity and with poorer set-shifting when using a derived metric to account for motoric slowing. Depression correlated with greater anxiety and disease severity, but not with cognitive performance.

CONCLUSIONS

Our findings support the association of anxiety with a specific domain of executive function, set-shifting, in nondemented individuals with mild to moderate PD, raising the possibility that treatment of anxiety may alleviate aspects of executive dysfunction in this population. (PsycINFO Database Record

The Effect of Balance Training on Postural Control in Patients with Parkinson's Disease Using a Virtual Rehabilitation System

OBJECTIVES

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor clinical alterations among others. Postural problems have serious consequences for patients, not only limiting their daily life but also increasing some risks, like the risk of fall. Inadequate postural control and postural instability is a major problem in PD patients. A Virtual Motor Rehabilitation System (VMR) has been tested in patients with PD in the intervention period. Our purpose was to analyze the evolution of the spatial postural control during the intervention period, to see if there are any changes caused precisely by this intervention.

METHODS

Ten people with PD carried out 15 virtual rehabilitation sessions. We tested a groundbreaking system based on Virtual Motor Rehabilitation in two periods of time (baseline evaluation and final evaluation). In the training sessions, the participants performed a customizable treatment using a low-cost system, the Active Balance Rehabilitation system (ABAR). We stored the pressure performed by the participants every five hundredths of a second, and we analyzed the patients' pressure when they maintained their body on the left, on the right, and in the center in sitting position. Our system was able to measure postural control in every patient in each of the virtual rehabilitation sessions.

RESULTS

There are no significant differences in the performance of postural control in any of the positions evaluated throughout the sessions. Moreover, the results show a trend to an improvement in all positions. This improvement is especially remarkable in the left/right positions, which are the most important positions in order to avoid problems such as the risk of fall. With regard to the suitability of the ABAR system, we have found outstanding results in enjoyment, success, clarity, and helpfulness.

CONCLUSIONS

Although PD is a progressive neurodegenerative disorder, the results demonstrate that patients with PD maintain or even improve their postural control in all positions. We think that the main factor influencing these results is that patients use more of their available cognitive processing to improve their postural control. The ABAR system allows us to make this assumption because the system requires the continuous attention of patients, promoting cognitive processing.

Neuropsychiatric symptoms in untreated Parkinson's disease

Neuropsychiatric and cognitive symptoms are common in Parkinson's disease (PD) and may precede and exceed motor symptoms as major factors impacting disease course and quality of life. Neuropsychiatric symptoms (NPS) in PD are various and are attributed to pathologic changes within multiple brain regions, to psychological stress, and to adverse effects of dopamine replacement therapy. Sleep disorders and mood symptoms such as apathy, depression, and anxiety may antedate the development of motor symptoms by years, while other NPS such as impulse control disorders, psychosis, and cognitive impairment are more common in later stages of the disease. Few studies report on NPS in the early, untreated phase of PD. We reviewed the current literature on NPS in PD with a focus on the early, drug-naive stages of PD. Among these early disease stages, premotor and early motor phases were separately addressed in our review, highlighting the underlying pathophysiological mechanisms as well as epidemiological characteristics, clinical features, risk factors, and available techniques of clinical assessment.

Computerized assessment of goal-directed behavior in Parkinson's disease

INTRODUCTION

Apathy is a syndrome characterized by a reduction in goal-directed behavior. Neurodegenerative diseases frequently exhibit apathy. However, we lack an objective measure of apathy. The Philadelphia Apathy Computerized Task (PACT) measures impairments in goal-directed behavior that contribute to apathy, including initiation, planning, and motivation. We sought to examine these mechanisms in Parkinson's disease (PD) patients.

METHOD

PD patients and healthy controls with a caregiver were recruited for the study. Participants were administered the PACT, a novel computerized assessment of goal-directed behavior based on reaction times, and the Starkstein Apathy Scale (AS). Care partners completed the Neuropsychiatric Inventory (NPI). Baseline demographic characteristics of PD and control participants were compared using t tests and Wilcoxon rank sum tests. Linear regressions were used to compare PD patients to controls on each of the three PACT subtasks (initiation, planning, and motivation) while controlling for motor slowing. We then compared performance on each PACT subtask between PD subjects defined as apathetic using the NPI and Starkstein Apathy Scale and controls.

RESULTS

We included 30 PD and 15 control participants in the analysis. When controlling for motor slowing, both all PD and PD apathetic subjects were significantly slower than controls on the planning task and on the initiation task. There were no significant differences between PD patients and controls on the motivation tasks.

CONCLUSIONS

PD patients showed specific initiation and planning deficits compared to control participants. After using traditional scales to define apathy, PD apathetic patients still exhibited impaired initiation and planning behaviors. These results suggest that the PACT measures aspects of impaired goal-directed behavior that may contribute to apathy in PD.

Levodopa modulates small-world architecture of functional brain networks in Parkinson's disease

BACKGROUND

PD is associated with disrupted connectivity to a large number of distributed brain regions. How the disease alters the functional topological organization of the brain, however, remains poorly understood. Furthermore, how levodopa modulates network topology in PD is largely unknown. The objective of this study was to use resting-state functional MRI and graph theory to determine how small-world architecture is altered in PD and affected by levodopa administration.

METHODS

Twenty-one PD patients and 20 controls underwent functional MRI scanning. PD patients were scanned off medication and 1 hour after 200 mg levodopa. Imaging data were analyzed using 226 nodes comprising 10 intrinsic brain networks. Correlation matrices were generated for each subject and converted into cost-thresholded, binarized adjacency matrices. Cost-integrated whole-brain global and local efficiencies were compared across groups and tested for relationships with disease duration and severity.

RESULTS

Data from 2 patients and 4 controls were excluded because of excess motion. Patients off medication showed no significant changes in global efficiency and overall local efficiency, but in a subnetwork analysis did show increased local efficiency in executive (P = 0.006) and salience (P = 0.018) networks. Levodopa significantly decreased local efficiency (P = 0.039) in patients except within the subcortical network, in which it significantly increased local efficiency (P = 0.007).

CONCLUSIONS

Levodopa modulates global and local efficiency measures of small-world topology in PD, suggesting that degeneration of nigrostriatal neurons in PD may be associated with a large-scale network reorganization and that levodopa tends to normalize the disrupted network topology in PD. © 2016 International Parkinson and Movement Disorder Society.

Validation of Neuropsychological Tests to Screen for Dementia in Chinese Patients With Parkinson's Disease

To compare the accuracy of different neuropsychological tests and their combinations for deriving reliable cognitive indices for dementia diagnosis in Parkinson's disease (PD). One hundred forty consecutive patients with PD were recruited and administrated an extensive battery of neuropsychological tests. Discriminant analysis and receiver-operator characteristic curve were used to evaluate their correct classifications and validity. Patients with PD having dementia (PDD; 23.5%) performed significantly worse in all tests than patients without dementia. Age of onset, disease duration, Hoehn-Yahr grade, Unified Parkinson's Disease Rating Scale part III scores, and education were associated with dementia in patients with PD. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and Block Design (BD) showed better specificity and sensitivity when used alone, and combined use of MMSE and BD further increased the validity. Our results indicated that the accuracy of MMSE was better in dementia diagnosis of Chinese patients with PD, and combined use of MMSE and BD could further increase the validity of dementia diagnosis.

Mood Differences Among Parkinson's Disease Patients With Mild Cognitive Impairment

Studies with healthy elderly adults suggest that apathy, depression, and anxiety are more common among individuals with mild cognitive impairment (MCI). This study examined differences in mood/amotivational symptoms among patients with Parkinson's disease (PD) with and without MCI. Patients with PD (N=214) underwent neurocognitive evaluations including assessment of apathy (Apathy Scale), depression (Beck Depression Inventory-II), and trait anxiety (State-Trait Anxiety Inventory trait scale). Trait anxiety and depression were more severe in patients with PD with MCI. Delineation of MCI into amnestic and nonamnestic subtypes revealed greater depression, apathy, and anxiety among patients with PD with amnestic MCI relative to cognitively intact patients with PD. Patients with PD and MCI report greater mood symptoms compared to patients with PD who are cognitively intact.

Antipsychotic-induced parkinsonism is associated with working memory deficits in schizophrenia-spectrum disorders

In view of the significant cognitive deficits in schizophrenia and their impact on patients' social and occupational functioning, and considering that the influence potential influence of antipsychotic-induced extrapyramidal symptoms on cognition in schizophrenia remains poorly understood, the current study sought to identify the clinical, socio-demographic and neurologic predictors of the cognitive performance of schizophrenia patients. Eighty-two schizophrenia-spectrum (DSM-IV criteria) outpatients were recruited. Psychiatric symptoms were evaluated with the Positive And Negative Syndrome Scale and the Calgary Depression Scale for Schizophrenia. Extrapyramidal symptoms were evaluated with the Extrapyramidal Symptoms Rating Scale, while spatial working, planning abilities and visual paired associates learning were evaluated with the CAmbridge Neuropsychological Tests Automated Battery. The Stroop test was also administered. Multivariate hierarchic linear regression analyses were performed. We found that negative symptoms were associated with cognitive flexibility, planning, visual learning and working memory performance in schizophrenia. Age, sex, number of hospitalizations and antipsychotic type also emerged as significant predictors. More importantly, we found a significant association between antipsychotic-induced parkinsonism and working memory performance. The fact that negative symptoms and socio-demographic variables predicted cognitive performance in schizophrenia is consistent with the previous literature on the topic. The finding of an association between parkinsonism and working memory may have clinical implications, since working memory deficits are considered putative endophenotypes of schizophrenia and are known to impair patients' social and occupational functioning. Our results will need to be replicated in longitudinal studies involving larger samples of patients.

Gender-specific brain regional variation of neurons, endogenous estrogen, neuroinflammation and glial cells during rotenone-induced mouse model of Parkinson's disease

Rotenone (RT) produces reactive oxygen species (ROS) by inhibiting the mitochondrial electron transport chain; causing dopaminergic (DA) cell death in the substantia nigra (SN) and simulates other models of induced Parkinson's disease (PD). There is a sincere dearth of knowledge regarding the status of glial cells, neuroprotective estrogen and the status of neuroinflammatory TNF-α in the different brain regions in either sex during healthy, as well as during PD conditions. In the present study of RT-induced mouse model of PD, we have selected the frontal cortex (FC), hippocampus (HC) and SN from either sex of Swiss albino mice as these are the major regions involved during PD pathogenesis. During non pathogenic conditions, the ROS-scavenging enzyme activity varied among the brain regions and also in between genders. The number of DOPA decarboxylase-positive cells, astrocytes and microglia was similar in the respective regions of the brain in both the sexes. The level of proinflammatory cytokine TNF-α was same in the respective FC and HC in either sex except that of SN. The expression level of estrogen and its receptors varied among the three brain regions. During RT treatment, ROS-scavenging enzyme activities increased, DOPA decarboxylase-positive neurons and fibers in DA as well as in norepinephrinergic (NE) systems become degenerated, number of astrocytes decreased and microglial cells increased in those specific brain regions in either of the sexes except in the SN region of males where astrocyte number remained unaltered and microglial cell percentage decreased. TNF-α increased in the FC and SN but remained unaltered in the HC of both sexes. Estradiol level decreased in the HC and SN but the level unevenly varied in the FC. Similarly, the estrogen bound and nuclear-cytosolic receptor α and β also varied differentially among the brain regions of the two sexes. Therefore our present study depicts that there exists a clear variation of neuronal and astroglial cell population, estrogen and its receptor levels in different brain regions of both the sexes during control and RT-treated pathogenic condition and these variations have major implication in PD pathogenesis and progression.

Alexithymia and apathy in Parkinson's disease: neurocognitive correlates

Non-motor symptoms such as neuropsychiatric and cognitive dysfunction have been found to be common in Parkinson’s disease (PD) but the relation between such symptoms is poorly understood. We focused on alexithymia, an impairment of affective and cognitive emotional processing, as there is evidence for its interaction with cognition in other disorders. Twenty-two non-demented PD patients and 22 matched normal control adults (NC) were administered rating scales assessing neuropsychiatric status, including alexithymia, apathy, and depression, and a series of neuropsychological tests. As expected, PD patients showed more alexithymia than NC, and there was a significant association between alexithymia and disease stage. Alexithymia was associated with performance on non-verbally mediated measures of executive and visuospatial function, but not on verbally mediated tasks. By contrast, there was no correlation between cognition and ratings of either depression or apathy. Our findings demonstrate a distinct association of alexithymia with non-verbal cognition in PD, implicating right hemisphere processes, and differentiate between alexithymia and other neuropsychiatric symptoms in regard to PD cognition.

Functional correlates of optic flow motion processing in Parkinson's disease

The visual input created by the relative motion between an individual and the environment, also called optic flow, influences the sense of self-motion, postural orientation, veering of gait, and visuospatial cognition. An optic flow network comprising visual motion areas V6, V3A, and MT+, as well as visuo-vestibular areas including posterior insula vestibular cortex (PIVC) and cingulate sulcus visual area (CSv), has been described as uniquely selective for parsing egomotion depth cues in humans. Individuals with Parkinson’s disease (PD) have known behavioral deficits in optic flow perception and visuospatial cognition compared to age- and education-matched control adults (MC). The present study used functional magnetic resonance imaging (fMRI) to investigate neural correlates related to impaired optic flow perception in PD. We conducted fMRI on 40 non-demented participants (23 PD and 17 MC) during passive viewing of simulated optic flow motion and random motion. We hypothesized that compared to the MC group, PD participants would show abnormal neural activity in regions comprising this optic flow network. MC participants showed robust activation across all regions in the optic flow network, consistent with studies in young adults, suggesting intact optic flow perception at the neural level in healthy aging. PD participants showed diminished activity compared to MC particularly within visual motion area MT+ and the visuo-vestibular region CSv. Further, activation in visuo-vestibular region CSv was associated with disease severity. These findings suggest that behavioral reports of impaired optic flow perception and visuospatial performance may be a result of impaired neural processing within visual motion and visuo-vestibular regions in PD.

Distinct neuropsychological correlates of cognitive, behavioral, and affective apathy sub-domains in acquired brain injury

Apathy has a high prevalence and a significant contribution to treatment and rehabilitation outcomes in acquired brain damage. Research on the disorder's neuropsychological correlates has produced mixed results. While the mixed picture may be due to the use of varied assessment tools on different patient populations, it is also the case that most studies treat apathy as a unitary syndrome. This is despite the evidence that apathy is a multifaceted and multidimensional syndrome. This study investigates the neuropsychological correlates of apathy in 49 patients with acquired brain damage. It further fractionates apathy symptoms into affective, cognitive, and behavioral sub-domains and investigates their individual relations with standard measures of affective, cognitive, and behavioral functioning. Global apathy scores were not related to any of these measures. Affective apathy was associated with emotion perception deficits, and cognitive apathy was associated with executive deficits on the Brixton test. These results demonstrate that treating apathy as a single entity may hide important correlates to apathy symptoms that become visible when the disorder is fractionated into its sub-domains. The study highlights the research and clinical importance of treating apathy as a multidimensional syndrome.

Cognitive impairment in early-stage non-demented Parkinson's disease patients

OBJECTIVES

In Parkinson's disease (PD), Parkinson's disease dementia (PDD) and Parkinson's disease-mild cognitive impairment (PD-MCI) are common. PD-MCI is a risk factor for developing PDD. Knowledge of cognition in early-stages PD is essential in understanding and predicting the dementia process.

MATERIALS AND METHODS

We describe the cognitive profile in early-stage PD patients with no prior clinical suspicion of cognitive impairment, depression or psychiatric disturbances, and investigate possible features distinguishing patients with cognitive deficits, defining a PD-MCI risk-profile. Single Photon Emission Computerized Tomography (SPECT) DaT-scan and neurological examination confirmed the diagnosis. Mini-mental state examination-, Addenbrooke's Cognitive Examination, Unified Parkinson's Disease Rating Scale scoring, Hoehn &Yahr/Activity of Daily Living staging and a neuropsychological test battery were applied. Mild cognitive impairment patients were identified according to modified criteria by Troster necessarily omitting subjective cognitive complaints. 80 patients, mean age 61.0 years (SD 6.6), mean duration of disease 3.4 years (SD 1.2) were included. 76 patients were neuropsychologically tested.

RESULTS

26 (34%) patients fulfilled modified PD-MCI criteria, 18 (69%) of these showed episodic memory deficits, 14 (54%) executive dysfunction, 13 (50%) language/praxis deficits, 12 (46%) visuospatial/constructional deficits and 9 (35%) attention/working memory deficits. Cognitive impairment was associated with higher Unified Parkinson's Disease Rating scale (UPDRS)-, bradykinesia- and rigidity scores and more symmetric distribution of symptoms, but not tremor scores. Patients with cognitive impairment were less educated. Other demographic and clinical variables were comparable.

CONCLUSIONS

34% of early-stage PD patients without prior clinical suspicion of cognitive impairment exhibit cognitive impairment, which is associated to disease severity, especially bradykinesia, rigidity, axial symptoms and less asymmetry of motor symptoms, even at early disease stages and when cognitive symptoms are mild.

Copper and copper proteins in Parkinson's disease

Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology.

Neural and behavioral substrates of subtypes of Parkinson's disease

Parkinson’s disease (PD) is a neurological disorder, associated with rigidity, bradykinesia, and resting tremor, among other motor symptoms. In addition, patients with PD also show cognitive and psychiatric dysfunction, including dementia, mild cognitive impairment (MCI), depression, hallucinations, among others. Interestingly, the occurrence of these symptoms—motor, cognitive, and psychiatric—vary among individuals, such that a subgroup of PD patients might show some of the symptoms, but another subgroup does not. This has prompted neurologists and scientists to subtype PD patients depending on the severity of symptoms they show. Neural studies have also mapped different motor, cognitive, and psychiatric symptoms in PD to different brain networks. In this review, we discuss the neural and behavioral substrates of most common subtypes of PD patients, that are related to the occurrence of: (a) resting tremor (vs. nontremor-dominant); (b) MCI; (c) dementia; (d) impulse control disorders (ICD); (e) depression; and/or (f) hallucinations. We end by discussing the relationship among subtypes of PD subgroups, and the relationship among motor, cognitive, psychiatric factors in PD.

Clinical characteristics with an impact on ADL functions of PD patients with cognitive impairment indicative of dementia

BACKGROUND

Dementia in Parkinson's disease (PD) is defined as cognitive decline severe enough to affect activities of daily living function (ADL). The aim of our exploratory study was to compare two groups of PD patients. Both groups had cognitive deficits severe enough to justify diagnosis of dementia, but they differed according to caregivers' rating on ADL dysfunction. Parameters which differed between the two groups were interpreted to affect the caregivers' perception of ADL dysfunction in PD patients with cognitive impairment indicative of Parkinson's disease dementia.

METHODOLOGY/PRINCIPAL FINDINGS

Thirty of 131 Parkinson's disease patients fulfilled the Movement Disorders Society Task Force - recommended, cognitive Level-I-criteria for dementia. According to standardized caregiver ratings, volunteers were grouped into 18 patients with (ADL-) and 12 without instrumental activities of daily living dysfunction (ADL+). Caregiver activities of daily living function ratings closely correlated with self-estimates of patients and those of physician (p<0.001). ADL- patients performed worse on tests assessing visual-construction (p<0.05) and attention (p=0.03) than ADL+ patients. Moreover, the postural instability and gait disorder subtype was more frequent in ADL- patients (p=0.009). ADL- patients tended to have more communication problems (p=0.05), more anxiety (p=0.05) and showed a tendency to be treated more often with neuroleptics (p=0.049) than ADL+.

CONCLUSIONS/SIGNIFICANCE

Results indicate that worse attention, visual-construction abilities, the postural instability and gait disorder subtype, communication problems, medication and presence of anxiety are related to activities of daily living dysfunctions in Parkinson's disease patients with cognitive decline indicative of dementia. Our data suggests that not only cognitive factors but also non-cognitive factors seem to be linked to the diagnosis of Parkinson's disease dementia associated with significant impact on instrumental activities of daily living function. Further studies with larger sample sizes are needed to verify our results.

In vivo detection of monoaminergic degeneration in early Parkinson disease by (18)F-9-fluoropropyl-(+)-dihydrotetrabenzazine PET

PET with (18)F-9-fluoropropyl-(+)-dihydrotetrabenzazine ((18)F-DTBZ), a novel radiotracer targeting vesicular monoamine transporter type 2 (VMAT2), has been proven as a useful imaging marker to measure dopaminergic integrity.

METHODS

The aim of this study was to evaluate the capability of (18)F-DTBZ PET in detecting the monoaminergic degeneration in early Parkinson disease (PD) in vivo. Seventeen age-matched healthy subjects and 30 PD patients at early stage of disease (duration of disease ≤ 5 y) with mild and unilateral motor symptoms underwent (18)F-DTBZ PET scans. The severity of disease, including Unified Parkinson Disease Rating Scale and modified Hoehn and Yahr Stage (mHY), were recorded at off-medication states. The standardized volumes of interest were applied to the spatial normalized image for quantification analysis. The specific uptake ratios (SURs) were calculated according to the formula (specific volumes-of-interest counts/occipital cortex counts) - 1. SUR measurements were summarized for each brain region.

RESULTS

The mean duration of disease in the PD group was 3.2 ± 2.1 y (range, 0.5-5 y). The mean mHY was 1.0 ± 0.1 (range, 1-1.5). The SURs of bilateral caudate, anterior putamen, posterior putamen, substantia nigra, and nucleus accumbens were significantly lower in PD patients than those of healthy subjects. The reduction of SURs was most severe in the contralateral (the brain regions that are located opposite to the symptomatic side) posterior putamen (-81%), followed by the ipsilateral posterior putamen (-67%). Receiver-operating-characteristic curve analysis showed that the SURs of the bilateral posterior putamen and contralateral anterior putamen had a sensitivity of 100% and specificity of 100% in differentiating PD patients from healthy subjects.

CONCLUSION

(18)F-DTBZ PET was as an excellent tool for the early diagnosis of PD. The obvious decline of (18)F-DTBZ uptake in the ipsilateral (asymptomatic) striatum suggested that (18)F-DTBZ PET might serve as an in vivo biomarker to detect the monoaminergic degeneration in the premotor phase of PD.

Apathy in Parkinson's disease: more than just executive dysfunction

Apathy is a frequent syndrome in Parkinson's disease (PD) usually associated with depression, cognitive impairment (CI), and dementia. Whereas executive dysfunction seems to play a major causative role in the development of apathy in PD, recent findings pointed for the possible participation of other underlying mechanisms in the development of clinically meaningful symptoms of apathy. By means of neuropsychological testing focused over global cognitive functioning, set-shifting, decision making, and cognitive effort, we compared to a control group, a carefully selected sample of PD patients presenting apathy as the only neuropsychiatric symptom and without clinically relevant signs of cognitive impairment. In addition to the previously reported executive dysfunction, apathetic patients also exhibited significant difficulties in tasks assessing for cortical functioning, such as naming and clock drawing. Moreover, apathetic patients performed significantly better on a decision-making task, although any of these differences appeared linked to a lack of effort when performing the tasks. On the basis of our findings, we discuss the possible implication of added mechanisms rather than just executive dysfunction in the development of apathy in PD.

Acute and chronic cognitive effects of levodopa and dopamine agonists on patients with Parkinson's disease: a review

The spatiotemporal progression of dopamine depletion in Parkinson's disease (PD) provides a special model for assessing dopaminergic effects on neural systems with differential baseline dopamine levels. This study aims at reviewing cognitive effects of dopaminergic stimulation in PD. While considering dopaminergic drugs (levodopa or dopamine agonists), temporal intervals (acute or chronic) and cognitive domains, we found that empirical evidence was almost focused on acute effects of levodopa on executive functions. The paucity of empirical evidence suggests that no meaningful conclusions can be actually drawn and further research is needed in relation to: (1) other cognitive domains; (2) the acute cognitive effects of dopamine agonists, as compared with levodopa; (3) possible differences between cognitive effects of different dopamine agonists; (4) the cognitive effects of chronic dopaminergic therapies. The latter issue is of particular clinical interest considering that many PD patients present a mild cognitive impairment: is this cognitive feature worsened or improved by the prolonged dopaminergic therapy? In addition to the potential risk of inducing dyskinesia and behavioral side effects such as impulse control disorders, also cognitive effects of prolonged dopaminergic treatments should be taken in account by clinicians in order to anticipate or to delay their prescription to PD patients.