Management of motor and non-motor symptoms in Parkinson's disease

The Priority Goals and Underlying Impairments Contributing to Goal-Related Problems of People with Parkinson's Disease Receiving a Community-Based Rehabilitation Program

Background

Goal setting is a core rehabilitation practice in Parkinson's disease (PD). Targeting therapy towards specific goals leads to greater improvements in performance and psychosocial outcomes. Goal setting in PD is feasible, and although the nature of goals has been described in previous studies, the underlying impairments related to goals have not been described. Understanding the nature of goals ensures that interventions for people with PD are aligned with their needs and priorities. Understanding the underlying impairments highlights which symptoms have the biggest impact on daily life and is necessary for planning appropriate interventions to target them.

Aim

To describe the nature of the goals of people with PD; the underlying impairments related to goals; and to compare differences between high and low priority goals.

Method

Deductive content analysis was used to map goal statements to the international classification of function (ICF) activity and participation category and to map therapist field notes detailing the primary underlying impairment to the ICF Body Functions category. These results were then compared across goal priority rankings.

Results

88 goals of 22 people with PD were analysed. We found that people with PD set diverse goals across all chapters of the ICF Activity and Participation category, with "self-care" goals making up the highest proportion of goals. The primary underlying impairment related to the goals was predominantly related to impairments in "mental functions" under the Body Functions category. Regardless of goal priority, most goal-related underlying impairments were found to be in the "mental functions" category.

Conclusion

The goals of this sample of community-dwelling people with PD highlight their diverse needs and priorities. These findings indicate that nonmotor symptoms, namely, executive dysfunction and amotivation most commonly impact the performance of and participation in activities of greatest importance to people with PD. This trial is registered with ACTRN12621001483842.

Cost-Effectiveness Analyses of Non-Pharmacological and Non-Surgical Interventions in Idiopathic Parkinson's Disease: A Systematic Review

Background

Interest in non-pharmacological/non-surgical interventions to treat Parkinson's disease (PD) has substantially increased. Although a few health-economic studies have been conducted, summary information on the cost-effectiveness is still scarce.

Objective

To give an overview of cost-effectiveness analyses (CEA) focusing on non-pharmacological/non-surgical interventions in PD patients.

Methods

A systematic literature search was conducted in five databases. Studies were included that provided cost-effectiveness analysis (CEA) or cost-utility analysis (CUA) of non-pharmacological/non-surgical interventions in PD patients. Study quality was assessed with the Drummond and CHEERS 2022 checklists respectively, for economic evaluation.

Results

N = 9 studies published between 2012-2023 were identified. Most studies undertook a CUA (n = 5); n = 3 reported a combination of CEA and CUA, and n = 1 a pure CEA. Most studies (n = 6) examined physical exercise. The CEA studies identified additional costs of 170€ -660€  for the improvement of one single unit of a clinical outcome and savings of 18.40€ -22.80€  per score gained as measured with established instruments. The four studies that found significant quality of life benefits show large variations in the incremental cost effectiveness ratio (ICER) of 3,220€ -214,226€  per quality-adjusted life year (QALY); notably interventions were heterogenous regarding content and intensity.

Conclusions

Despite increasing numbers of non-pharmacological/non-surgical intervention trials in PD patients, health-economic evaluations are rare. The examined intervention types and health-economic results vary greatly. Together with the heterogeneity of the health-economic studies these factors limit the conclusions that can be drawn. Further research and a standardization of methods is needed to allow decision makers to make meaningful interpretations, and to allocate scarce resources.

Exploring the Efficacy of the Effortful Swallow Maneuver for Improving Swallowing in People With Parkinson Disease-A Pilot Study

Objectives

To determine the immediate (compensatory) and longer term (rehabilitative) effect of the effortful swallow (ES) maneuver on physiological swallowing parameters in Parkinson disease.

Design

Virtual intervention protocol via Microsoft Teams with pre- and post-videofluoroscopic swallowing studies.

Setting

Outpatient hospital setting, with intervention performed virtually.

Participants

Eight participants (median age 74 years [63-82])with Parkinson disease (years post onset 3-20) with a Hoehn and Yahr scale score between 2 and 4 (N=8).

Interventions

ES maneuver, initiated using a maximum effort isometric tongue-to-palate press, with biofeedback provided using the Iowa Oral Performance Instrument. The protocol included 30 minute sessions twice daily, 5 days/week for 4 weeks.

Main Outcome Measures

Penetration-Aspiration Scale scores, time-to-laryngeal-vestibule-closure, total pharyngeal residue, and pharyngeal area at maximum constriction as seen on lateral view videofluoroscopy.

Results

No consistent, systematic trends were identified in the direction of improvement or deterioration across Penetration-Aspiration Scale scores, time-to-laryngeal-vestibule-closure, pharyngeal area at maximum constriction, or total pharyngeal residue.

Conclusions

Heterogeneous response to the ES as both a compensatory and rehabilitative technique. Positive response on the compensatory probe was predictive of positive response after rehabilitation.

Molecular mechanisms underlying the neuroprotection of environmental enrichment in Parkinson's disease

Parkinson's disease is the most common movement disorder, affecting about 1% of the population over the age of 60 years. Parkinson's disease is characterized clinically by resting tremor, bradykinesia, rigidity and postural instability, as a result of the progressive loss of nigrostriatal dopaminergic neurons. In addition to this neuronal cell loss, Parkinson's disease is characterized by the accumulation of intracellular protein aggregates, Lewy bodies and Lewy neurites, composed primarily of the protein α-synuclein. Although it was first described almost 200 years ago, there are no disease-modifying drugs to treat patients with Parkinson's disease. In addition to conventional therapies, non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders. Among such strategies, environmental enrichment, comprising physical exercise, cognitive stimulus, and social interactions, has been assessed in preclinical models of Parkinson's disease. Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression, enhancing the expression of neurotrophic factors and modulating neurotransmission. In this review article, we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson's disease, highlighting its influence on the dopaminergic, cholinergic, glutamatergic and GABAergic systems, as well as the involvement of neurotrophic factors. We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson's disease, highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.

Formulation and characterization of pramipexole containing buccal films for using in Parkinson's disease

Parkinson's disease (PD) is neurodegenerative chronic illness which affects primarily the elderly over 45 years of age. The symptoms can be various, both non-motor and motor symptoms can appear. The biggest problem in the treatment of the disease is the difficulty in swallowing for the patients. However, buccal patches can solve this problem because the patients do not have to swallow the dosage form, and during application, the API can absorb from the area of the buccal mucosa quickly without causing a foreign body sensation. In our present study, we focused on the development of buccal polymer films with pramipexole dihydrochloride (PR). Films with different compositions were formulated and their mechanical properties and chemical interactions were investigated. The biocompatibility of the film compositions was examined on the TR146 buccal cell line. The permeation of PR was also monitored across the TR146 human cell line. It can be stated that the plasticizer can enhance the thickness and the breaking hardness of the films, while not decreasing their mucoadhesivity significantly. All formulations proved to have cell viability higher than 87%. Finally, we found the best composition (3% SA+1% GLY-PR-Sample1) which can be applied on the buccal mucosa in the treatment of PD.

Non-visual hallucinations in Parkinson's disease: a systematic review

BACKGROUND

Non-visual hallucinations in Parkinson's disease (PD) can be prevalent and distressing. Most existing research has however, focused on visual hallucinations as well as related risk factors. The current study thus conducted a systematic review to collate existing evidence on non-visual hallucinations in PD, focusing on their prevalence, phenomenology, and clinical-cognitive correlates.

METHODS

Ninety-one relevant studies were included from a systematic search across PsycINFO APA, PubMed, and Web of Science, for peer-reviewed publications in the English language, from 1970 to the present. These comprised a mix of case (30 studies; n = 56) and group design (62 studies; n = 7346) studies, divided into three somewhat overlapping collections to address our three research foci.

RESULTS

Prevalence estimates for hallucinations were: auditory 1.5-72.0%, olfactory 1.6-21.0%, somatic-tactile 0.4-22.5%, gustatory 1.0-15.0%, and sensed presence 0.9-73.3%. Phenomenological inquiries revealed descriptions of vivid, consuming events replete with elaborate detail, adversely affecting PD patients in different ways. Overt experiences of multisensory hallucinations were also highly variable (0.4-80%) but exceedingly common, reported by almost half of the 45 included prevalence studies. There was some evidence for modality-specific hallucination predictors, but this was largely tentative, pending robust replication.

CONCLUSIONS

Marked prevalence figures coupled with phenomenological descriptions implicating distress denote that non-visual and multisensory hallucinations in PD are of clinical significance. More direct research and clinical attention need to be devoted to the study and management of such hallucinatory experiences.

Efficacy of Repetitive Trans-spinal Magnetic Stimulation for Patients with Parkinson's Disease: a Randomised Controlled Trial

We evaluated the effect of repetitive trans-spinal magnetic stimulation (rTSMS) in patients with Parkinson's disease (PD) in a randomised, single-blind study. Participants were hospitalised and administered a single trial of rTSMS or sham treatment 2 days a week for 4 weeks. In addition, all participants underwent rehabilitation 5 days a week for 4 weeks. The primary outcome was the difference between the two groups in the mean change from baseline to post-training in the total score on the Unified Parkinson's Disease Rating Scale (UPDRS). Secondary endpoints included the differences between the two groups in the mean change on the UPDRS part III (motor) score and the Timed Up and Go (TUG) score. Eligible participants were randomly assigned to either the rTSMS group (n = 50) or sham group (n = 50). The between-group difference in mean change in the total UPDRS score was 10.28 (95% confidence interval (CI), 4.42 to 16.13; P = 0.014) immediately after intervention from baseline, 5.04 (95% CI, - 5.41 to 15.50; P = 0.024) 3 months after intervention from baseline and 2.38 (95% CI, 7.18 to 11.85; P = 0.045) 6 months after intervention from baseline. Significant differences between groups in UPDRS part III and TUG scores were maintained more strictly than those in the UPDRS total score. These results strongly indicate that rTSMS promotes the effect of rehabilitation on motor function in patients with PD.

Quality of life of patients with Parkinson's disease: a comparison between preoperative and postoperative states among those who were treated with deep brain stimulation

BACKGROUND

Deep brain stimulation (DBS) is a well-established procedure for treating Parkinson's disease (PD). Although its mechanisms of action are still unclear, improvements in motor symptoms and reductions in medication side effects can be achieved for a significant proportion of patients, with consequent enhancement of quality of life.

OBJECTIVE

To investigate the impact of DBS on the quality of life of PD patients.

METHODS

This was a retrospective longitudinal study with collection of historical data in a neurosurgery center, from June 2019 to December 2020. The sample was obtained according to convenience, and the Parkinson's Disease Questionnaire (PDQ-39), Unified Parkinson's Disease Rating Scale (UPDRS) III and IV, Trail-Making Test and Verbal Fluency Test were used.

RESULTS

Data were collected from 17 patients (13 with subthalamic nucleus DBS and 4 with globus pallidus pars interna DBS). Significant improvement (p=0.008) on the UPDRS III was observed in comparing the preoperative without DBS with the postoperative with DBS. About 47.0% of the patients showed post-surgical improvement in QoL (p=0.29). Thirteen patients were able to complete part A of the Trail-Making Test and four of these also completed part B. Almost 60% of the patients scored sufficiently on the semantic test, whereas only 11.8% scored sufficiently on the orthographic evaluation. No association between implant site and test performance could be traced.

CONCLUSIONS

Improvements in quality of life and motor function were observed in the majority of the patients enrolled. Despite the limitations of this study, DBS strongly benefits a significant proportion of PD patients when well indicated.

Exploring sexual dysfunction in care homes

Sexual needs and sexuality in older adults continues to be a neglected area of clinical intervention, particularly in longer term care settings. This is often due to older adults in long term care beds presenting with increased frailty, and often with significant neurocognitive disorders, making it difficult for care staff to evaluate the capacity of an older adult resident to participate in sexual activities or a sexual relationship. Talking about sexuality, intimacy and sexual health can be embarrassing at any age and sex is often still considered taboo for people who live in care homes. The World Health Organization recently declared that sexual health is a central aspect of life and that each individual has the right to love and be loved, to receive appropriate information and treatment, and to enable intimate relationships and personal control over sexual behavior. This chapter explores sexual behaviors, and barriers to this, in later life, and focuses on the sexual behavior of care home residents with Parkinson's disease. Reasons for sexual dysfunction, potential age-related changes to sexual functioning, along with issues such as changes to body image, intimacy and hyper sexuality, are examined for people with Parkinson's disease. Recommendations for practice are given, and acknowledge that older people may still want to be sexually active or intimate is the first step to addressing the issues and overcoming any barriers.

Inhibition of anandamide hydrolysis does not rescue respiratory abnormalities observed in an animal model of Parkinson's disease

NEW FINDINGS

What is the central question of this study? The respiratory frequency to hypercapnia is attenuated in an animal model of Parkinson's disease (PD): what is the therapeutic potential of inhibition of anandamide hydrolysis for this respiratory deficit? What is the main finding and its importance? In an animal model of PD there is an increased variability in resting respiratory frequency and an impaired tachypnoeic response to hypercapnia, which is accompanied by diminished expression of Phox2b immunoreactivity in the retrotrapezoid nucleus (RTN). Inhibition of anandamide hydrolysis also impaired the response to hypercapnia and decreased the number of Phox2b immunoreactive cells in the RTN. This strategy does not reverse the respiratory deficits observed in an animal model of PD.

ABSTRACT

Parkinson's disease (PD) is characterized by severe classic motor symptoms along with various non-classic symptoms. Among the non-classic symptoms, respiratory dysfunctions are increasingly recognized as contributory factors to complications in PD. The endocannabinoid system has been proposed as a target to treat PD and other neurodegenerative disorders. Since symptom management of PD is mainly focused on the classic motor symptoms, in this work we aimed to test the hypothesis that increasing the actions of the endocannabinoid anandamide by inhibiting its hydrolysis with URB597 reverses the respiratory deficits observed in an animal model of PD. Results show that bilateral injection of 6-hydroxydopamine hydrochloride (6-OHDA) in the dorsal striatum leads to neurodegeneration of the substantia nigra, accompanied by reduced expression of Phox2b in the retrotrapezoid nucleus (RTN), an increase in resting respiratory frequency variability and an impaired tachypnoeic response to hypercapnia. URB597 treatment in control animals was associated with an impaired tachypnoeic response to hypercapnia and a reduced expression of Phox2b in the RTN, whereas treatment of 6-OHDA-lesioned animals with URB597 was not able to reverse the deficits observed. These results suggest that targeting anandamide may not be a suitable strategy to treat PD since this treatment mimics the respiratory deficits observed in the 6-OHDA model of PD.

Parkinson's disease related alterations in cannabinoid transmission

Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNc) by neurodegeneration. Recent findings in animal models of PD propose tonic inhibition of the remaining DA neurons through GABA release from reactive glial cells. Movement dysfunctions could be ameliorated by promotion of activity in dormant DA cells. The endocannabinoid system (ECS) is extensively present in basal ganglia (BG) and is known as an indirect modulator of DAergic neurotransmission, thus drugs designed to target this system have shown promising therapeutic potential in PD patients. Interestingly, down/up-regulation of cannabinoid receptors (CBRs) varies across the different stages of PD, suggesting that some of the motor/ non-motor deficits may be related to changes in CBRs. Determination of the profile of changes of these receptors across the different stages of PD as well as their neural distribution within the BG could improve understanding of PD and identify pathways important in disease pathobiology. In this review, we focus on temporal and spatial alterations of CBRs during PD in the BG. At present, as inconclusive, but suggestive results have been obtained, future investigations should be conducted to extend preclinical studies examining CBRs changes within each stage in controlled clinical trials in order to determine the potential of targeting CBRs in management of PD.

Human wildtype tau expression in cholinergic pedunculopontine tegmental neurons is sufficient to produce PSP-like behavioural deficits and neuropathology

Progressive Supranuclear Palsy (PSP) is the most common atypical parkinsonism and exhibits hallmark symptomology including motor function impairment and dysexecutive dementia. In contrast to Parkinson's disease, the underlying pathology displays aggregation of the protein tau, which is also seen in disorders such as Alzheimer's disease. Currently, there are no pharmacological treatments for PSP, and drug discovery efforts are hindered by the lack of an animal model specific to PSP. Based on previous results and clinical pathology, it was hypothesized that viral deposition of tau in cholinergic neurons within the hindbrain would produce a tauopathy along neural connections to produce PSP-like symptomology and pathology. By using a combination of ChAT-CRE rats and CRE-dependent AAV vectors, wildtype human tau (the PSP-relevant 1N4R isoform; hTau) was expressed in hindbrain cholinergic neurons. Compared to control subjects (GFP), rats with tau expression displayed deficits in a variety of behavioural paradigms: acoustic startle reflex, marble burying, horizontal ladder and hindlimb motor reflex. Postmortem, the hTau rats had significantly reduced number of cholinergic pedunculopontine tegmentum and dopaminergic substantia nigra neurons, as well as abnormal tau deposits. This preclinical model has multiple points of convergence with the clinical features of PSP, some of which distinguish between PSP and Parkinson's disease.

Cardiovascular Events Associated with Antipsychotics in Newly Diagnosed Parkinson's Disease Patients: A Propensity Score Matched Cohort Study

Purpose

Observational studies have examined the association between antipsychotics and ischemic heart disease (IHD) in general populations, but results did not take into account other comorbid diseases, such as Parkinson's disease (PD). This study investigates the one-year risk of IHD, all cardiovascular events, and all-cause mortality among newly diagnosed PD patients who used antipsychotics compared to non-users.

Materials and Methods

This study included individuals aged 40 years or older with a first definitive PD diagnosis Read Code in the Secure Anonymised Information Linkage (SAIL) databank who had been initiated on any PD medication between 2000 and 2016. Antipsychotic users were matched 1:1 with non-users by a propensity score model to control the confounding effects of patients' demographics, social deprivation status, comorbidities, and medication history. Cox regression was performed to calculate the hazard ratios (HR) and 95% CIs for the association between antipsychotics and study outcomes.

Results

A total of 1837 participants were included in the analysis. Users of first-generation antipsychotics (FGA) were significantly more likely to develop IHD compared to non-users, with an HR of 2.60 (95% CI 1.103-6.167). Among the FGAs, haloperidol had the highest likelihood of IHD developing, with an HR of 3.01 (95% CI 1.038-8.729). Any use of antipsychotics, regardless of whether they were FGA or second-generation antipsychotics (SGA), was linked to all-cause mortality, with an HR of 4.201 (95% CI 3.272-5.394). When subdividing antipsychotics into FGAs and SGAs, mortality was more likely in FGA users, with an HR of 7.557 (95% CI 5.633-10.139). Mortality also occurred in SGA users, but with a lower HR of 3.278 (95% CI 2.509-4.282).

Conclusion

FGAs were associated with an increased risk of IHD and all-cause mortality in newly diagnosed PD patients with psychosis. This finding emphasizes the need to use antipsychotics with caution in PD patients with psychosis.

Exploring the Use of Intracranial and Extracranial (Remote) Photobiomodulation Devices in Parkinson's Disease: A Comparison of Direct and Indirect Systemic Stimulations

In recent times, photobiomodulation has been shown to be beneficial in animal models of Parkinson's disease, improving locomotive behavior and being neuroprotective. Early observations in people with Parkinson's disease have been positive also, with improvements in the non-motor symptoms of the disease being evident most consistently. Although the precise mechanisms behind these improvements are not clear, two have been proposed: direct stimulation, where light reaches and acts directly on the distressed neurons, and remote stimulation, where light influences cells and/or molecules that provide systemic protection, thereby acting indirectly on distressed neurons. In relation to Parkinson's disease, given that the major zone of pathology lies deep in the brain and that light from an extracranial or external photobiomodulation device would not reach these vulnerable regions, stimulating the distressed neurons directly would require intracranial delivery of light using a device implanted close to the vulnerable regions. For indirect systemic stimulation, photobiomodulation could be applied to either the head and scalp, using a transcranial helmet, or to a more remote body part (e.g., abdomen, leg). In this review, we discuss the evidence for both the direct and indirect neuroprotective effects of photobiomodulation in Parkinson's disease and propose that both types of treatment modality, when working together using both intracranial and extracranial devices, provide the best therapeutic option.

'Striving for normality' when coping with Parkinson's disease in everyday life: A metasynthesis

BACKGROUND

Parkinson's disease is a chronic, progressive neurodegenerative disease which affects more than ten million people worldwide. Living with Parkinson's disease has a high impact on everyday life, and may affect quality of life negatively. Individualized coping strategies are needed to deal with the disease on a daily basis and still enjoy a social life.

OBJECTIVE

The aim of this study was to identify and describe strategies for coping adopted by individuals living with Parkinson's disease in their daily lives.

DESIGN

The study is designed as a meta-ethnographic metasynthesis and follows Sandelowski and Barroso's guidelines for synthesizing qualitative research.

DATASOURCES

Based on an exhaustive literature search in the following databases: CINAHL, MEDLINE, PsychINFO, Scopus and Swemed, as well as Mednar, parkinson.org, Google Scholar and OpenGrey, with no limit on the search date, 14 articles were included.

REVIEW METHODS

The data were analyzed through a taxonomic and inductive analysis focusing on coping with Parkinson's disease in daily life.

RESULTS

The findings revealed that the overarching motivation for patients to cope with Parkinson's disease was maintaining normality and preserving the self. The coping strategies used were: Staying independent, Focusing on the present and Avoiding challenging situations.

CONCLUSIONS

Coping with Parkinson's disease is an ongoing and complex process of balancing the strategies used, while holding on to the 'self' that pre-dated Parkinson's disease, and at the same time adjusting one's identity to embrace living with a chronic condition. In this process, optimism and positive thinking would seem to be very fruitful. Further, the synthesis revealed that relatives often act as informal caregivers and hence as an important support in daily life. Healthcare professionals must know about coping strategies in order better to support the patients.

Alterations of Nigral Dopamine Levels in Parkinson's Disease after Environmental Enrichment and PACAP Treatment in Aging Rats

The neuroprotective effects of environmental enrichment and PACAP (pituitary adenylate cyclase-activating polypeptide) are well-described in Parkinson’s disease. The aim of our study is to investigate the beneficial effects of these factors in aging parkinsonian rats. Newborn Wistar rats were divided into standard and enriched groups according to their environmental conditions. Standard animals were raised under regular conditions. During the first five postnatal weeks, enriched pups were placed in larger cages with different objects. Aging animals received (1) saline, (2) 6-hydroxidopamine (6-OHDA), or (3) 6-OHDA + PACAP injections into the left substantia nigra (s.n.). On the seventh postoperative day, the left and right s.n. were collected. The s.n. of young and aging unoperated animals were also examined in our experiment. We determined the dopamine (DA) levels by the HPLC-MS technique, while the sandwich ELISA method was used to measure the Parkinson disease protein 7 (PARK7) protein levels. In healthy animals, we found an age-related decrease of DA levels. In aging parkinsonian-enriched rats, the operation did not result in a significant DA loss. PACAP treatment could prevent the DA loss in both the standard and enriched groups. All injured PACAP-treated rats showed remarkably higher protective PARK7 levels. The protective effect of PACAP correlated with the increase of the DA and PARK7 levels.

Impact of Antidepressants on Cardiac Events and All-Cause Mortality in Parkinson's Disease: A National Data-Linkage Study

PURPOSE

This study investigated the 1-year risk of ischemic heart disease (IHD), all cardiovascular events, and all-cause mortality among newly diagnosed Parkinson's disease (PD) patients who used antidepressants compared to those who did not.

PATIENTS AND METHODS

Patients with PD aged 40 years or older were identified using data from 2000 through 2016 held within the Welsh Secure Anonymized Information Linkage (SAIL) databank. Antidepressant users were propensity-score matched 1:1 with non-users, adjusting for patients' demographics, socioeconomic status, and multiple comorbidities. Cox proportional hazard regression analyses were performed to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between the antidepressants and the study outcomes. The follow-up period was 1 year after the initial prescription of antidepressants.

RESULTS

The study group comprised a total of 3364 participants, with numbers split equally between the antidepressant-user and non-user groups, based on the propensity score-matching process. Overall, the propensity score-adjusted model showed that antidepressant usage in PD patients was not significantly associated with the risk of IHD (HR = 1.05; 95% CI 0.63-1.75) or all cardiovascular events (HR = 1.01; 95% CI 0.71-1.45) compared to non-users. The propensity score-adjusted model also showed that the use of any antidepressant, regardless of its category, was not statistically significantly associated with all-cause mortality (HR = 0.81; 95% CI 0.65-1.02). However, this association reached statistical significance in the multivariate adjusted model (HR = 0.67; 95% CI 0.54-0.84).

CONCLUSION

There was no evidence that antidepressant use was associated with an increased risk of IHD or all cardiovascular events in newly diagnosed PD patients who suffered from depression. Furthermore, antidepressant use might reduce the mortality rate in PD patients during the first year after initiation.

Factors influencing self-management in Parkinson's disease: A cross-sectional study

This study aimed to identify factors influencing self-management in patients with Parkinson's disease (PD) based on social cognitive theory. A cross-sectional design was used; data were collected at three tertiary medical centers in Korea from a convenience sample of 356 PD patients. Higher self-management scores were associated with higher education level, having a religion, and higher family income. Self-management score was positively correlated with activities of daily living, self-efficacy, and social support, and negatively correlated with non-motor symptoms. Hierarchical regression analysis revealed that demographic factors and non-motor symptoms explained 26.2% of the variance in self-management in PD. The explanatory power increased by 7.5% when self-efficacy was added, and by 6.7% when social support was added. Assessment of self-management in patients with PD should consider self-efficacy and social support, along with demographic factors and non-motor symptoms. Self-management programs that reflect these factors may be useful for improving self-management in PD patients.

Research-based Updates in Swallowing and Communication Dysfunction in Parkinson Disease: Implications for Evaluation and Management

PURPOSE

Individuals with Parkinson disease (PD) present with complex and variable symptoms, with recent findings suggesting that the etiology of PD extends beyond the involvement of just the basal ganglia. These symptoms include significant impairments in the speech and swallowing domains, which can greatly affect quality of life and therefore require therapeutic attention. This research-based update reviews the neurophysiological basis for swallowing and speech changes in PD, the effectiveness of various types of treatments, and implications for symptom evaluation and management.

CONCLUSION

The mechanisms responsible for swallowing and speech symptoms in PD remain largely unknown. Dopaminergic medication and deep-brain-stimulation do not provide consistent benefits for these symptoms suggesting a non-dopaminergic network is involved. Importantly, evidence suggests that symptoms of dysphagia and hypokinetic dysarthria may be early indications of PD, so it is critical to investigate the cause of these changes.

Rotigotine Transdermal Patch: A Review in Parkinson's Disease

Rotigotine (Neupro^®), a non-ergolinic dopamine agonist (DA), is administered once daily via a transdermal patch (TP) that delivers the drug over a 24-h period. In the EU, the rotigotine TP is approved as monotherapy for the treatment of early Parkinson's disease (PD) and as combination therapy with levodopa throughout the course of the disease. It is also approved for the treatment of PD in numerous other countries, including Australia, the USA, China and Japan. Rotigotine TP effectively improved motor and overall functioning in clinical trials in Caucasian and Asian patients with early PD (as monotherapy) or advanced PD (in combination with levodopa); treatment benefits appeared to be maintained in open-label extensions that followed patients for up to 6 years. Rotigotine TP was not consistently non-inferior to ropinirole and pramipexole in studies that included these oral non-ergolinic DAs as active comparators. Rotigotine TP variously improved some non-motor symptoms of PD, in particular sleep disturbances and health-related quality of life (HRQOL), based on findings from individual studies and/or a meta-analysis. Rotigotine TP was generally well tolerated, with an adverse event profile characterized by adverse events typical of dopaminergic stimulation and transdermal patch application. Available for more than a decade, rotigotine TP is a well-established, once-daily DA formulation for use in the short- and longer-term treatment of PD. It offers a convenient alternative when non-oral administration of medication is preferred and may be particularly useful in patients with gastrointestinal disturbances that reduce the suitability of oral medication.

Impacto dos sintomas de ansiedade na qualidade de vida na doença de Parkinson: uma revisão sistemática

RESUMO Objetivo: Revisar estudos relacionados ao impacto da ansiedade na qualidade de vida em pacientes com doença de Parkinson. Métodos: Trata-se de uma revisão sistemática realizada nos bancos de dados PubMed, Scopus, Web of Science e PsycINFO, com os descritores: “anxiety”, “Parkinson's disease” e “quality of life”. Foram selecionados 20 artigos publicados em inglês e sem limite de tempo. Resultado: A maioria dos estudos demonstrou correlação direta entre ansiedade e qualidade de vida em indivíduos com doença de Parkinson. Apenas dois estudos não encontraram essa associação. A presença de sintomas de ansiedade parece estar relacionada com a gravidade dos sintomas motores, sexo feminino e idade mais jovem, levando a um impacto maior na qualidade de vida. Conclusão: Os artigos analisados mostraram que a ansiedade tem impacto negativo sobre a qualidade de vida de indivíduos com doença de Parkinson.

Pedunculopontine tegmentum cholinergic loss leads to a progressive decline in motor abilities and neuropathological changes resembling progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is the most common atypical Parkinsonism. Although PSP shares some symptomology with Parkinson's disease (PD), PSP has a different underlying pathology characterized by tau aggregation. Furthermore, PSP sufferers respond poorly to PD medications and there are no effective alternative therapeutics. The development of both palliative and disease altering therapeutics has been hampered by the lack of an animal model that displays relevant PSP-like pathology and behavioral deficits. Previously, our lab found that in rats the selective removal of cholinergic pedunculopontine neurons (whose axonal projections overlap with areas of PSP pathology), mimics the extensive loss of cholinergic pedunculopontine neurons seen in PSP, and produces a unique PSP-like combination of deficits in: startle reflex, attention, and motor function. The present study extends those findings by allowing the lesion to incubate for over a year and compares behavioral and post-mortem pathology of pedunculopontine-cholinergic-lesioned and sham-lesioned rats. There was an early startle reflex deficit which did not improve over time. Progressive declines in motor function developed over the course of the year, including an increase in the number of "slips" while navigating various beams and poorly coordinated transitions from an elevated platform into homecages. Histological analysis discovered that the loss off cholinergic pedunculopontine neurons precipitated a significant loss of substantia nigra tyrosine hydroxylase-positive neurons and a significant enlargement of the lateral ventricles. The latter is a distinguishing feature between PSP and PD. This preclinical animal model of PSP has the potential to further our understanding of PSP and aid in the testing of potential therapeutic agents.

Predictive model for health-related quality of life in patients with Parkinson's disease

This study was conducted to develop and test a prediction model that explains health-related quality of life (HRQoL) of patients with Parkinson's disease (PD). Participants were 248 patients with PD enrolled in the neurology clinic of a university hospital in Seoul, Korea. The data were collected through structured questionnaires from March 1 to July 5, 2013. Motor fluctuations, depression, sleep disturbances, fatigue, and activities of daily living had significant direct effects on the quality of life of PD patients. Disease severity, social support, pain, sleep disturbances, fatigue, and activities of daily living had significant indirect effects on patients' quality of life. These predictive variables explained 77.4% of the total variance. The assessment of HRQoL in PD should be considered along with the variables affecting it, including social support. In addition, strategies to enhance social support may be useful for improving the quality of life for patients with PD.

Severely Affected by Parkinson Disease: The Patient's View and Implications for Palliative Care

INTRODUCTION

People severely affected by Parkinson disease (PD)/atypical parkinsonism (AP) comprise a heterogeneous group with distinct needs, which so far remain largely unexamined. The aim of our study was to analyze reasons for feeling severely affected and document unmet needs in a patient subgroup severely affected by PD/AP using solely a subjective inclusion criterion.

METHODS

Patients feeling severely affected by PD/AP were recruited via a magazine published by the German Parkinson Association. A questionnaire was sent out nationwide. Besides analyzing the closed-ended questions, a subsample of 40% was analyzed regarding the open-ended questions using content analysis. Correlations between subjectively felt severe affectedness and objective criteria were calculated.

RESULTS

Eight hundred fourteen questionnaires were analyzed. Sample characteristics were: mean age 70 years; 60.3% male; time since diagnosis up to 37 years; and Hoehn and Yahr score (if known) 3 (44.6%), followed by 4 (23.9%). Significant associations were observed between subjectively felt severe affectedness and Hoehn and Yahr ( P ≤ .05), poorer health ( P ≤ .01), higher nursing care level ( P ≤ 0.01), and having no children ( P ≤ .05). Most common reasons for feeling severely affected were mobility impairment (34.9%), coordination problems (17.0%), speech problems (12.2%), and limited day-to-day activities (7.8%). Most often expressed unmet needs were support in everyday life (28.1%), medical treatment (15.2%), help with financial services (11.6%), and social integration (9.9%).

CONCLUSIONS

To meet the complex needs, an integrated multidisciplinary and multiprofessional approach is indicated befitting palliative care principles. Herein, home-based services seem of special importance for patients in advanced disease stages.

Neuropathology of Nonmotor Symptoms of Parkinson's Disease

Parkinson's disease (PD), a multiorgan neurodegenerative disorder associated with α-synuclein deposits throughout the nervous system and many organs, is clinically characterized by motor and nonmotor features, many of the latter antedating motor dysfunctions by 20 or more years. The causes of the nonmotor manifestations such as olfactory, autonomic, sensory, neuropsychiatric, visuospatial, sleep, and other disorders are unlikely to be related to single lesions. They are mediated by the involvement of both dopaminergic and nondopaminergic systems, and diverse structures outside the nigrostriatal system that is mainly responsible for the motor features of PD. The nonmotor alterations appear in early/prodromal stages of the disease and its further progression, suggesting a topographical and chronological spread of the lesions. This lends further support for the notion that PD is a multiorgan proteinopathy, although the exact relationship between presymptomatic and later developing nonmotor features of PD and neuropathology awaits further elucidation.

Absence of regulator of G-protein signaling 4 does not protect against dopamine neuron dysfunction and injury in the mouse 6-hydroxydopamine lesion model of Parkinson's disease

Regulator of G-protein signaling 4 (RGS4), a member of the RGS family of proteins that inactivate G-proteins, has gained interest as a potential drug target for neurological disorders, such as epilepsy and Parkinson's disease (PD). In the case of PD, the main current options for alleviating motor symptoms are dopamine replacement therapies, which have limitations because of side effects and reduced effectiveness over the long term. Research on new nondopaminergic PD drug targets has indicated that inhibition of RGS4 could be an effective adjuvant treatment option. The effectiveness of RGS4 inhibition for an array of PD-linked functional and structural neuroprotection end points has not yet been demonstrated. Here, we use the 6-hydroxydopamine (6-OHDA) lesioning model of the nigrostriatal pathway in mice to address this question. We observe, using a battery of behavioral and pathological measures, that mice deficient for RGS4 are not protected from 6-OHDA-induced injury and show enhanced susceptibility in some measures of motor function. Our results suggest that inhibition of RGS4 as a nondopaminergic target for PD should be approached with caution.

Safinamide: A Review in Parkinson's Disease

Safinamide (Xadago^®) is an orally active, selective, reversible monoamine oxidase-B inhibitor with both dopaminergic and non-dopaminergic (glutamatergic) properties. In the EU, safinamide is approved for the treatment of mid- to late-stage fluctuating Parkinson's disease (PD) as add-on therapy to a stable dose of levodopa alone or in combination with other PD medications. Safinamide 50-100 mg/day administered as a fixed or flexible dose significantly increased daily 'on' time without dyskinesia (primary endpoint) in patients with mid- to late-stage PD with motor fluctuations in 24-week, placebo-controlled clinical trials. Other outcomes, including motor function, overall clinical status and health-related quality of life, were also generally improved with safinamide. Furthermore, in an 18-month extension of one study, although dyskinesia (primary endpoint) was not significantly improved with safinamide relative to placebo, treatment benefits in other outcomes were generally sustained over 24 months of treatment. Safinamide was generally well tolerated in clinical trials; dyskinesia was the most common adverse event. Although further studies are needed, including comparative and long-term studies, current evidence indicates that safinamide extends the treatment options available for use as add-on therapy to levodopa and other PD medications in patients with mid- to late-stage PD experiencing motor fluctuations.

First-in-human assessment of PRX002, an anti-α-synuclein monoclonal antibody, in healthy volunteers

BACKGROUND

α-Synuclein is a major component of pathologic inclusions that characterize Parkinson's disease. PRX002 is an antibody that targets α-synuclein, and its murine parent antibody 9E4 has been shown in preclinical studies to reduce α-synuclein pathology and to protect against cognitive and motor deteriorations and progressive neurodegeneration in human α-synuclein transgenic mice.

METHODS

This first-in-human, randomized, double-blind, placebo-controlled, phase 1 study assessed the impact of PRX002 administered to 40 healthy participants in 5 ascending-dose cohorts (n = 8/cohort) in which participants were randomly assigned to receive a single intravenous infusion of study drug (0.3, 1, 3, 10, or 30 mg/kg; n = 6/cohort) or placebo (n = 2/cohort).

RESULTS

PRX002 demonstrated favorable safety, tolerability, and pharmacokinetic profiles at all doses tested, with no immunogenicity. No serious adverse events, discontinuations as a result of adverse events, or dose-limiting toxicities were reported. Serum PRX002 exposure was dose proportional; the average terminal half-life across all doses was 18.2 days. A significant dose-dependent reduction in free serum α-synuclein (unbound to PRX002) was apparent within 1 hour after PRX002 administration, whereas total α-synuclein (free plus bound) increased dose-dependently, presumably because of the expected change in kinetics following antibody binding.

CONCLUSIONS

This study demonstrates that serum α-synuclein can be safely modulated in a dose-dependent manner after single intravenous infusions of an anti-α-synuclein antibody. These findings support continued development of PRX002, including further characterization of its safety, tolerability, pharmacokinetics, and pharmacodynamic effects in the central nervous system in patients with Parkinson's disease. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Parkinson's disease between internal medicine and neurology

General medical problems and complications have a major impact on the quality of life in all stages of Parkinson's disease. To introduce an effective treatment, a comprehensive analysis of the various clinical symptoms must be undertaken. One must distinguish between (1) diseases which arise independently of Parkinson's disease, and (2) diseases which are a direct or indirect consequence of Parkinson's disease. Medical comorbidity may induce additional limitations to physical strength and coping strategies, and may thus restrict the efficacy of the physical therapy which is essential for treating hypokinetic-rigid symptoms. In selecting the appropriate medication for the treatment of any additional medical symptoms, which may arise, its limitations, contraindications and interactions with dopaminergic substances have to be taken into consideration. General medical symptoms and organ manifestations may also arise as a direct consequence of the autonomic dysfunction associated with Parkinson's disease. As the disease progresses, additional non-parkinsonian symptoms can be of concern. Furthermore, the side effects of Parkinson medications may necessitate the involvement of other medical specialists. In this review, we will discuss the various general medical aspects of Parkinson's disease.

Long-Term Treatment with High-Dose Thiamine in Parkinson Disease: An Open-Label Pilot Study

OBJECTIVES

To investigate the potential clinical, restorative, and neuroprotective effects of long-term treatment with thiamine in Parkinson disease (PD).

DESIGN

Observational open-label pilot study.

SETTING

Outpatient neurologic rehabilitation clinic.

PATIENTS AND METHODS

Starting in June 2012, we have recruited 50 patients with PD (33 men and 17 women; mean age, 70.4 ± 12.9 years; mean disease duration, 7.3 ± 6.7 years). All the patients were assessed at baseline with the Unified Parkinson's Disease Rating Scale (UPDRS) and the Fatigue Severity Scale (FSS) and began treatment with 100 mg of thiamine administered intramuscularly twice a week, without any change to personal therapy. All the patients were re-evaluated after 1 month and then every 3 months during treatment.

RESULTS

Thiamine treatment led to significant improvement of motor and nonmotor symptoms: mean UPDRS scores (parts I-IV) improved from 38.55 ± 15.24 to 18.16 ± 15.08 (p = 2.4 × 10(-14), t test for paired data) within 3 months and remained stable over time; motor UPDRS part III score improved from 22.01 ± 8.57 to 9.92 ± 8.66 (p = 3.1 × 10(-22)). Some patients with a milder phenotype had complete clinical recovery. FSS scores, in six patients who had fatigue, improved from 53.00 ± 8.17 to 23.60 ± 7.77 (p < 0.0001, t test for paired data). Follow-up duration ranged from 95 to 831 days (mean, 291.6 ± 207.2 days).

CONCLUSIONS

Administration of parenteral high-dose thiamine was effective in reversing PD motor and nonmotor symptoms. The clinical improvement was stable over time in all the patients. From our clinical evidence, we hypothesize that a dysfunction of thiamine-dependent metabolic processes could cause selective neural damage in the centers typically affected by this disease and might be a fundamental molecular event provoking neurodegeneration. Thiamine could have both restorative and neuroprotective action in PD.

Nonpharmacological treatments for patients with Parkinson's disease

Since 2013, a number of studies have enhanced the literature and have guided clinicians on viable treatment interventions outside of pharmacotherapy and surgery. Thirty-three randomized controlled trials and one large observational study on exercise and physiotherapy were published in this period. Four randomized controlled trials focused on dance interventions, eight on treatment of cognition and behavior, two on occupational therapy, and two on speech and language therapy (the latter two specifically addressed dysphagia). Three randomized controlled trials focused on multidisciplinary care models, one study on telemedicine, and four studies on alternative interventions, including music therapy and mindfulness. These studies attest to the marked interest in these therapeutic approaches and the increasing evidence base that places nonpharmacological treatments firmly within the integrated repertoire of treatment options in Parkinson's disease.

Neuropathobiology of non-motor symptoms in Parkinson disease

Parkinson disease (PD) is a multisystem disorder associated with α-synuclein aggregates throughout the central, autonomic, and peripheral nervous system, clinically characterized by motor and non-motor (NM) symptoms. The NMS in PD, many of which antedating motor dysfunction and representing a preclinical phase spanning 20 or more years, are linked to widespread distribution of α-synuclein pathology not restricted to the dopaminergic nigrostriatal system that is responsible for core motor features of PD. The pathologic substrate of NM manifestations such as olfactory, autonomic (gastrointestinal, urogenital, cardia, respiratory), sensory, skin, sleep, visual, neuropsychiatric dysfunctions (cognitive, mood, dementia), and others are critically reviewed. In addition to non-nigral brainstem nuclei, α-synuclein pathology involves sympathetic and parasympathetic, enteric, cardiac and pelvic plexuses, and many other organs indicating a topographical and chronological spread, particularly in the prodromal stages of the disease. Few animal models recapitulate NMS in PD. The relationship between regional α-synuclein/Lewy pathology, neurodegeneration and the corresponding clinical deficits awaits further elucidation. Controlled clinicopathologic studies will refine the correlations between presymptomatic and late-developing NM features of PD and neuropathology, and new premotor biomarkers will facilitate early diagnosis of PD as a basis for more effective preventive and therapeutic options of this devastating disease.

Nonmotor symptoms in sporadic versus familial forms of Parkinson's disease

SUMMARY 

Besides the classical motor symptoms, Parkinson's disease (PD) patients experience a wide range of nonmotor symptoms (NMS) throughout the disease course. However, due to the lack of recognition and understanding of the pathogenesis, NMS symptoms may be overlooked. Familial PD is a well-defined group that can provide a good model to investigate the mechanisms for both motor and NMS in PD. Some studies suggest that the frequency of NMS is not different between genetic and sporadic form of PD while others suggest that specific domains (such as neuropsychiatric symptoms) are more common in the genetic form. Early recognition of NMS may facilitate early diagnosis and monitoring of both sporadic and genetic PD.

LC-MS-based urinary metabolite signatures in idiopathic Parkinson's disease

Increasing evidence has shown that abnormal metabolic phenotypes in body fluids reflect the pathogenesis and pathophysiology of Parkinson's disease (PD). These body fluids include urine; however, the relationship between, specifically, urinary metabolic phenotypes and PD is not fully understood. In this study, urinary metabolites from a total of 401 clinical urine samples collected from 106 idiopathic PD patients and 104 normal control subjects were profiled by using high-performance liquid chromatography coupled to high-resolution mass spectrometry. Our study revealed significant correlation between clinical phenotype and urinary metabolite profile. Metabolic profiles of idiopathic PD patients differed significantly and consistently from normal controls, with related metabolic pathway variations observed in steroidogenesis, fatty acid beta-oxidation, histidine metabolism, phenylalanine metabolism, tryptophan metabolism, nucleotide metabolism, and tyrosine metabolism. In the fruit fly Drosophila melanogaster, the alteration of the kynurenine pathway in tryptophan metabolism corresponded with pathogenic changes in the alpha-synuclein overexpressed Drosophila model of PD. The results suggest that LC-MS-based urinary metabolomic profiling can reveal the metabolite signatures and related variations in metabolic pathways that characterize PD. Consistent PD-related changes across species may provide the basis for understanding metabolic regulation of PD at the molecular level.

The α7 nicotinic receptor agonist ABT-107 protects against nigrostriatal damage in rats with unilateral 6-hydroxydopamine lesions

The finding that smoking is inversely correlated with Parkinson's disease and that nicotine attenuates nigrostriatal damage in Parkinsonian animals supports the idea that nicotine may be neuroprotective. Nicotine is thought to exert this effect by acting at nicotinic receptors (nAChRs), including the α7 subtype. The objective of this study was twofold: first, to test the protective potential of ABT-107, an agonist with high selectivity for α7 nAChRs; and second, to investigate its cellular mechanism of action. Rats were implanted with minipumps containing ABT-107 (0.25mg/kg/d). In addition, we tested the effect of nicotine (1mg/kg/d) as a positive control, and also DMXB (2mg/kg/d) which acts primarily with α7 but also α4β2* nAChRs. Two weeks after minipump placement, the rats were lesioned by unilateral administration of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. Lesioning alone decreased contralateral forelimb use and adjusted stepping, two measures of Parkinsonism. ABT-107 and nicotine treatment significantly improved these behaviors at all weeks tested, with variable improvement with DMXB. We next investigated the cellular mechanism involved. The striatal dopamine transporter (DAT), a marker of dopaminergic integrity, was reduced ~70% with lesioning. ABT-107 or nicotine treatment significantly increased DAT levels in lesioned striatum; these drugs did not alter DAT levels in intact striatum. ABT-107 and nicotine also significantly improved basal dopamine release from lesioned striatum, as well as nicotine-stimulated dopamine release mediated via α4β2* and α6β2* nAChRs. These data suggest that α7 nAChR agonists may improve motor behaviors associated with nigrostriatal damage by enhancing striatal dopaminergic function.

Advances in non-dopaminergic treatments for Parkinson's disease

Since the 1960's treatments for Parkinson's disease (PD) have traditionally been directed to restore or replace dopamine, with L-Dopa being the gold standard. However, chronic L-Dopa use is associated with debilitating dyskinesias, limiting its effectiveness. This has resulted in extensive efforts to develop new therapies that work in ways other than restoring or replacing dopamine. Here we describe newly emerging non-dopaminergic therapeutic strategies for PD, including drugs targeting adenosine, glutamate, adrenergic, and serotonin receptors, as well as GLP-1 agonists, calcium channel blockers, iron chelators, anti-inflammatories, neurotrophic factors, and gene therapies. We provide a detailed account of their success in animal models and their translation to human clinical trials. We then consider how advances in understanding the mechanisms of PD, genetics, the possibility that PD may consist of multiple disease states, understanding of the etiology of PD in non-dopaminergic regions as well as advances in clinical trial design will be essential for ongoing advances. We conclude that despite the challenges ahead, patients have much cause for optimism that novel therapeutics that offer better disease management and/or which slow disease progression are inevitable.

Amantadine and cognitive flexibility: decision making in Parkinson's patients with severe pathological gambling and other impulse control disorders

INTRODUCTION

Dopamine replacement therapy for Parkinson's disease (PD) was recently linked to the development of impulse control disorders such as pathological gambling (PG), hypersexuality, compulsive shopping, and binge or compulsive eating. Antiglutamatergic agents including amantadine (Ama) reduce these behaviors in PD and non-PD patients. The aim of our study is to evaluate the changes in executive functions, emotions, and reward/loss processing during Ama treatment in PD patients.

METHODS

Thirty-three patients affected by idiopathic PD were selected from a cohort of 1,096 PD patients and categorized in three different groups: ten affected by PG (PD-PG); nine PD patients with other impulse control disorder (PD-ICD); and 14 PD patient without any psychiatric disorder (PD-CTR-controls). For the neuropsychological evaluation, the following behavioral tasks where administered: the Stroop, the emotional Stroop, and the monetary reward/loss risk-taking tasks.

RESULTS

During Ama treatment, PD-PGs showed a decrease in risky choices and an increase in non-risky choices (t(9)=-2.40, P<0.05 and t(9)=2,67, P<0.05 uncorrected, respectively). Between-group comparison showed a significant decrease in risky choices for PD-PG with respect to PD-CTR (t(22)=-4.16, P<0.01), and a decreased accuracy for positive words in comparison between PD-PG and PD-ICD (t(17)=-7,49, P<0.01) and PD-PG and PD-CTR (t(22)=-4.29, P<0.01). No within- and between-group differences were observed for Stroop task.

DISCUSSION

Our data showed that Ama add-on therapy reduces hypersensitivity to reward and sustains activation toward uncertainty in PD-PG patients. These finding might explain the behavioral mechanism underlying the effect of antiglutamatergic drugs.