Disrupted reward processing in Parkinson’s disease and its relationship with dopamine state and neuropsychiatric syndromes: a systematic review and meta-analysis

BackgroundNeuropsychiatric symptoms are common in Parkinson’s disease (PD) and predict poorer outcomes. Reward processing dysfunction is a candidate mechanism for the development of psychiatric symptoms including depression and impulse control disorders (ICDs). We aimed to determine whether reward processing is impaired in PD and its relationship with neuropsychiatric syndromes and dopamine replacement therapy.MethodsThe Ovid MEDLINE/PubMed, Embase and PsycInfo databases were searched for articles published up to 5 November 2020. Studies reporting reward processing task performance by patients with PD and healthy controls were included. Summary statistics comparing reward processing between groups were converted to standardised mean difference (SMD) scores and meta-analysed using a random effects model.ResultsWe identified 55 studies containing 2578 participants (1638 PD and 940 healthy controls). Studies assessing three subcomponent categories of reward processing tasks were included: option valuation (n=12), reinforcement learning (n=37) and reward response vigour (n=6). Across all studies, patients with PD on medication exhibited a small-to-medium impairment versus healthy controls (SMD=0.34; 95% CI 0.14 to 0.53), with greater impairments observed off dopaminergic medication in within-subjects designs (SMD=0.43, 95% CI 0.29 to 0.57). Within-subjects subcomponent analysis revealed impaired processing off medication on option valuation (SMD=0.57, 95% CI 0.39 to 0.75) and reward response vigour (SMD=0.36, 95% CI 0.13 to 0.59) tasks. However, the opposite applied for reinforcement learning, which relative to healthy controls was impaired on-medication (SMD=0.45, 95% CI 0.25 to 0.65) but not off-medication (SMD=0.28, 95% CI −0.03 to 0.59). ICD was the only neuropsychiatric syndrome with sufficient studies (n=13) for meta-analysis, but no significant impairment was identified compared tonon-ICD patients (SMD=−0.02, 95% CI −0.43 to 0.39).ConclusionReward processing disruption in PD differs according to subcomponent and dopamine medication state, and warrants further study as a potential treatment target and mechanism underlying associated neuropsychiatric syndromes.

The Optimistic View to Uncertainty. Benefits of Real Option Valuation Methodology in Project Valuation; Example of its Application for a Rail Terminal Modification Project

The two main factors that drive the shift to liquid cracking in the Middle East are the restricted availability of ethane and the fact that naphtha or mixed feed cracking provides us with a much more diverse product mix. This opens the path to a higher share of performance chemicals. Building petrochemical complexes based on liquid or mixed feed cracking requires very complicated downstream configurations at a high level of integration with refinery streams. The value created by such a project rests on the ability of the operator to solve complex optimization problems in a volatile market environment. Inevitably, the correctness of the investment decision rests on the ability of the management to determine the value of the project under conditions of uncertainty regarding the future market prices. This paper demonstrates how the approach that was developed originally for the option valuation, can be used to address the problem of project assessment under the conditions of uncertainty. A real-life example of an investment decision about a modification of a rail terminal is used to illustrate the problem and to present a solution to it. Building on this example further, the paper argues that the method of Real Option valuation can support a creation of a competitive advantage in the conditions of uncertainty.

Disrupted reward processing in Parkinson's Disease and its relationship with dopamine state and neuropsychiatric syndromes: a systematic review and meta-analysis

Background: Neuropsychiatric symptoms are common in Parkinsons disease (PD) and predict poorer outcomes. Reward processing dysfunction is a candidate mechanism for the development of psychiatric symptoms including depression and impulse control disorders (ICD). We aimed to determine whether reward processing is impaired in PD and its relationship with neuropsychiatric syndromes and dopamine replacement therapy. Methods: The Ovid MEDLINE/PubMed, Embase and PsycInfo databases were searched for articles published up to November 5th, 2020. Studies reporting reward processing task performance by PD patients and healthy controls were included. Summary statistics comparing reward processing between groups were converted to standardized mean difference (SMD) scores and meta-analysed using a random effects model. Results: We identified 55 studies containing 2578 participants (1,638 PD and 940 healthy controls). Studies assessing three subcomponent categories of reward processing tasks were included: Option Valuation (n=12), Reinforcement Learning (n=37) and Reward Response Vigour (n=6). Across all studies, PD patients on medication exhibited a small-to-medium impairment versus healthy controls (SMD=0.34; 95%CI 0.14-0.53), with greater impairments observed off dopaminergic medication in within-subjects designs (SMD=0.43, 95%CI 0.29-0.57). Within-subjects subcomponent analysis revealed impaired processing off medication on Option Valuation (SMD=0.57, 95%CI 0.39-0.75) and Reward Response Vigour (SMD=0.36, 95%CI 0.13-0.59) tasks. However, the opposite applied for Reinforcement Learning, which relative to healthy controls was impaired on-medication (SMD=0.45, 95%CI 0.25-0.65) but not off-medication (SMD=0.28, 95%CI -0.03-0.59). ICD was the only neuropsychiatric syndrome with sufficient studies (n=13) for meta-analysis, but no significant impairment was identified compared to non-ICD patients (SMD=-0.02, 95%CI -0.43-0.39). Conclusion: Reward processing disruption in PD differs according to subcomponent and dopamine medication state and warrants further study as a potential treatment target and mechanism underlying associated neuropsychiatric syndromes.

Option Valuation in the Presence of Market Sentiment: Application to Listed Companies in the CAC40 Index

Asset pricing theory based on rationality was widely criticized in literature. Indeed, the non-inclusion of investor behavior and assuming market efficiency led to the weaknesses of option valuation through the traditional Black and Scholes model (1973). In this paper we examine the effect of the inclusion of investor behavior in the option pricing model. We test whether the Black and Scholes model in presence of sentiment behavior can lead to an improvement of the calculation of call price. Using daily data of 30 listed companies of France in the CAC40 index for the period June 18, 2009 to May 09, 2018, results showed that the introduction of sentiment effect in the Black and Scholes model provides better estimates of the call price than that obtained by the standard Black-Scholes model. In fact, we obtain an average gain of about 44% in terms of relative change in mean square error between both methods.