From DYMUS to DYPARK: validation of a screening questionnaire for dysphagia in Parkinson's disease

Dysphagia is a common debilitating symptom in people with Parkinson's Disease (PD), adequate screening of swallowing disorders is fundamental. The DYMUS questionnaire has shown very good characteristics for the screening of dysphagia in Multiple Sclerosis, and it might also prove useful for screening dysphagia in PD. The primary aim was to test and validate the DYMUS questionnaire in PD patients. This is an observational multicentric study involving 103 patients affected by PD. All subjects filled in the DYMUS and the Eating Assessment Tool (EAT-10) questionnaires. A subgroup of patients (n = 53) underwent a fiber-optic endoscopic evaluation of swallowing (FEES) and their dysphagia was scored by means of the Dysphagia Outcome Severity Scale (DOSS). DYMUS showed a relatively high level of internal consistency (Cronbach's alpha 0.79). A significant positive correlation was found between the DYMUS and the EAT-10 scores (p < 0.001), while a negative correlation was found between the DYMUS and the DOSS scores (p < 0.001). DYMUS showed a good sensitivity and specificity compared to FEES for detecting dysphagia (area under the curve: 0.82, p < 0.001). The ROC curve analysis showed that a DYMUS score >= 6 represents a reliable cut-off for the risk of dysphagia. The DYMUS questionnaire proved to be a reliable screening tool to detect dysphagia in patients suffering from PD. It is easy to understand, it can be self-administered and therefore adequate for adoption in the clinical practice with the more convenient name of DYPARK

Liquidity-adjusted Market Risk Measures with Stochastic Holding Period

Within the context of risk integration, we introduce in risk measurement stochastic holding period (SHP) models. This is done in order to obtain a `liquidity-adjusted risk measure' characterized by the absence of a fixed time horizon. The underlying assumption is that - due to changes on market liquidity conditions - one operates along an `operational time' to which the P&L process of liquidating a market portfolio is referred. This framework leads to a mixture of distributions for the portfolio returns, potentially allowing for skewness, heavy tails and extreme scenarios. We analyze the impact of possible distributional choices for the SHP. In a multivariate setting, we hint at the possible introduction of dependent SHP processes, which potentially lead to non linear dependence among the P&L processes and therefore to tail dependence across assets in the portfolio, although this may require drastic choices on the SHP distributions. We also find that increasing dependence as measured by Kendall's tau through common SHP's appears to be unfeasible. We finally discuss potential developments following future availability of market data.

Expected Shortfall as a Tool for Financial Risk Management

We study the properties of Expected Shortfall from the point of view of financial risk management. This measure --- which emerges as a natural remedy in some cases where Value at Risk (VaR) is not able to distinguish portfolios which bear different levels of risk --- is indeed shown to have much better properties than VaR. We show in fact that unlike VaR this variable is in general subadditive and therefore it is a Coherent Measure of Risk in the sense of reference (artzner)