Non-invasive stimulation techniques to relieve abdominal/pelvic pain: is more always better?

Chronic abdominal and pelvic pain is a common condition that has significant impact on quality of life, and causes billions of dollars in direct and indirect costs. Emerging data suggest that transcranial direct current stimulation (tDCS), alone or in combination with transcutaneous electrical nerve stimulation TENS), could be a promising therapeutic avenue to reduce chronic pain. The encouraging results coming from these studies prompted us to try combining TENS and tDCS in 4 of our patients who suffered from chronic abdominal/pelvic pain and to compare the effect with 5 other patients who received TENS alone. Pain intensity was assessed with a visual analog scale before, during and after the stimulation. We observed that there was a slight decrease in pain which was similar in both patient groups (TENS alone and TENS combined with tDCS). These observations suggest that combining TENS and tDCS in patients suffering from chronic pelvic and/or abdominal pain produces no additional benefit, compared to TENS alone. Future studies, looking at the effect of several/consecutive TENS and tDCS sessions should be conducted

On the Complexity of SPEs in Parity Games

We study the complexity of problems related to subgame-perfect equilibria (SPEs) in infinite duration non zero-sum multiplayer games played on finite graphs with parity objectives. We present new complexity results that close gaps in the literature. Our techniques are based on a recent characterization of SPEs in prefix-independent games that is grounded on the notions of requirements and negotiation, and according to which the plays supported by SPEs are exactly the plays consistent with the requirement that is the least fixed point of the negotiation function. The new results are as follows. First, checking that a given requirement is a fixed point of the negotiation function is an NP-complete problem. Second, we show that the SPE constrained existence problem is NP-complete, this problem was previously known to be ExpTime-easy and NP-hard. Third, the SPE constrained existence problem is fixed-parameter tractable when the number of players and of colors are parameters. Fourth, deciding whether some requirement is the least fixed point of the negotiation function is complete for the second level of the Boolean hierarchy. Finally, the SPE-verification problem -- that is, the problem of deciding whether there exists a play supported by a SPE that satisfies some LTL formula -- is PSpace-complete, this problem was known to be ExpTime-easy and PSpace-hard

Rational verification and checking for Nash and subgame-perfect equilibria in graph games

We study two natural problems about rational behaviors in multiplayer non-zero-sum sequential infinite duration games played on graphs: checking problems, that consist in deciding whether a strategy profile, defined by a Mealy machine, is rational; and rational verification, that consists in deciding whether all the rational answers to a given strategy satisfy some specification. We give the complexities of those problems for two major concepts of rationality: Nash equilibria and subgame-perfect equilibria, and for five major classes of payoff functions: parity, mean-payoff, quantitative reachability, energy, and discounted-sum

Subgame-perfect Equilibria in Mean-payoff Games

In this paper, we provide an effective characterization of all the subgame-perfect equilibria in infinite duration games played on finite graphs with mean-payoff objectives. To this end, we introduce the notion of requirement and the notion of negotiation function. We establish that the set of plays that are supported by SPEs are exactly those that are consistent with the least fixed point of the negotiation function. Finally, we show that the negotiation function is piecewise linear and can be analyzed using the linear algebraic tool box

Développement de méthodes d'analyse de standards pharmaceutiques par électrophorèse capillaire

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

High- and low-frequency transcutaneous electrical nerve stimulation does not reduce experimental pain in elderly individuals

Abstract : Despite its widespread clinical use, the efficacy of transcutaneous electrical nerve stimulation (TENS) remains poorly documented in elderly individuals. In this randomized, double-blind crossover study, we compared the efficacy of high-frequency (HF), lowfrequency (LF), and placebo (P) TENS in a group of 15 elderly adults (mean age: 67 6 5 years). The effect of HF-, LF-, and P-TENS was also evaluated in a group of 15 young individuals (26 6 5 years; same study design) to validate the effectiveness of the TENS protocols that were used in the elderly group. Each participant came to the laboratory on 3 separate occasions to receive, in random order, HF-, LF-, and P-TENS. Pain intensity and pain perception thresholds were assessed before, during, and after TENS, using an experimental heat pain paradigm. For the young group, there was a significant decrease in pain intensity during and after HF- and LF-TENS when compared with baseline, with both HF- and LF-TENS being superior to P-TENS. In the older group, HF- and LF-TENS did not reduce pain when compared with baseline and no difference was observed between the 2 active TENS sessions and P-TENS. High-frequency, LF-, and P-TENS all increased pain thresholds in young individuals, whereas in older individuals, only LF-TENS increased pain thresholds. Taken together, these results suggest that TENS is effective in young, but not in older, individuals. Future studies should be conducted to confirm these results in pain populations and to identify strategies that could enhance the effect of TENS in the elderly

Reminiscing or playing? The power of early parent-child metacognitive interactions across contexts

peer reviewe

Discuter du passé : une manière de stimuler le développement de la mémoire épisodique d'enfants d'âge préscolaire

peer reviewe