Sérgio Rocha

Site‐specific effects of mental practice combined with transcranial direct current stimulation on motor learning

Mental practice can induce significant neural plasticity and result in motor performance improvement if associated with motor imagery tasks. Given the effects of transcranial direct current stimulation (tDCS) on neuroplasticity, the current study tested whether tDCS, using different electrode montages, can increase the neuroplastic effects of mental imagery on motor learning. Eighteen healthy right‐handed adults underwent a randomised sham‐controlled crossover experiment to receive mental training combined with either sham or active anodal tDCS of the right primary motor cortex (M1), right supplementary motor area, right premotor area, right cerebellum or left dorsolateral prefrontal cortex (DLPFC). Motor performance was assessed by a blinded rater using: non‐dominant handwriting time and legibility, and mentally trained task at baseline (pre) and immediately after (post) mental practice combined with tDCS. Active tDCS significantly enhances the motor‐imagery‐induced improvement in motor function as compared with sham tDCS. There was a specific effect for the site of stimulation such that effects were only observed after M1 and DLPFC stimulation during mental practice. These findings provide new insights into motor imagery training and point out that two cortical targets (M1 and DLPFC) are significantly associated with the neuroplastic effects of mental imagery on motor learning. Further studies should explore a similar paradigm in patients with brain lesions.

The impact of transcranial direct current stimulation (tDCS) combined with modified constraint-induced movement therapy (mCIMT) on upper limb function in chronic stroke: a double-blind randomized controlled trial

Abstract Purpose: This pilot double-blind sham-controlled randomized trial aimed to determine if the addition of anodal tDCS on the affected hemisphere or cathodal tDCS on unaffected hemisphere to modified constraint-induced movement therapy (mCIMT) would be superior to constraints therapy alone in improving upper limb function in chronic stroke patients. Methods: Twenty-one patients with chronic stroke were randomly assigned to receive 12 sessions of either (i) anodal, (ii) cathodal or (iii) sham tDCS combined with mCIMT. Fugl–Meyer assessment (FMA), motor activity log scale (MAL), and handgrip strength were analyzed before, immediately, and 1 month (follow-up) after the treatment. Minimal clinically important difference (mCID) was defined as an increase of ≥5.25 in the upper limb FMA. Results: An increase in the FMA scores between the baseline and post-intervention and follow-up for active tDCS group was observed, whereas no difference was observed in the sham group. At post-intervention and follow-up, when compared with the sham group, only the anodal tDCS group achieved an improvement in the FMA scores. ANOVA showed that all groups demonstrated similar improvement over time for MAL and handgrip strength. In the active tDCS groups, 7/7 (anodal tDCS) 5/7 (cathodal tDCS) of patients experienced mCID against 3/7 in the sham group. Conclusion: The results support the merit of association of mCIMT with brain stimulation to augment clinical gains in rehabilitation after stroke. However, the anodal tDCS seems to have greater impact than the cathodal tDCS in increasing the mCIMT effects on motor function of chronic stroke patients. Implications for Rehabilitation The association of mCIMT with brain stimulation improves clinical gains in rehabilitation after stroke. The improvement in motor recovery (assessed by Fugl–Meyer scale) was only observed after anodal tDCS. The modulation of damaged hemisphere demonstrated greater improvements than the modulation of unaffected hemispheres.

Joint Water Quantity-Quality Management in a Biofuel Production Area—Integrated Economic-Hydrologic Modeling Analysis

Water management in the Pirapama River Basin in northeastern Brazil is affected by both water quantity and water quality constraints. The region is known for significant sugarcane-based ethanol production—which is the key to the Brazilian economy and expected to grow dramatically under recent changes in climate and energy policies. Sugarcane production in the region goes hand in hand with controlled fertirrigation practices with potentially significant adverse impacts on the environment. To assess sustainable water allocation in the basin, an integrated hydrologic-economic basin model is adapted to study both water quantity and quality aspects. The model results show that incorporating water quality aspects into water allocation decisions leads to a substantial reduction in application of vinasse to sugarcane fields. Embedding highly nonlinear water quality constraints in a basin optimization model is demonstrated to be an effective tool to address the water management problems in rapidly developing biofuel areas of Brazil and elsewhere. DOI: 10.1061/ASCEWR.1943-5452.0000049 CE Database subject headings: Water quality; River basins; Hydrologic models; Optimization; Biomass; Economic factors; Brazil. Author keywords: Water quality; River-basin management; Integrated economic-hydrologic modeling; Nonlinear optimization; Biofuel. Background The Pirapama River Basin is located in the metropolitan regions of Recife—locally known as Regiao Metropolitana do Recife RMR and the Pernambuco Mata in northeastern Brazil see Fig. 1. It covers an area of about 600 km 2 and the approximate length of its main waterway is 80 km. The Pirapama is the most important water source for the city of Recife, capital of the state of Pernambuco. The region is affected by a lack of adequate water and sewage treatment resulting in high levels of water pollution during dry spells Ribeiro 2000. Throughout the length of the river most currently monitored water quality standards cannot be

Transcranial direct current stimulation in the prophylactic treatment of migraine based on interictal visual cortex excitability abnormalities: A pilot randomized controlled trial

PURPOSE The aims of this paper are (i) to compare the excitability of visual cortex in migraine patients with healthy volunteers; and (ii) if an abnormal excitability has been found, to modulate cortical excitability in migraine patients with transcranial direct current stimulation (tDCS) and observe their clinical and neurophysiological effects. METHODS The study was divided into two steps. A cross-sectional study (step 1) was conducted to compare the cortical excitability of 23 migraineurs (11 with and 12 without aura) on 11 healthy individuals. On step 2, a randomized, double blinded, controlled pilot trial was carried on with 19 migraineurs, randomly divided into: experimental and control group. During 12 sessions, experimental and group received active tDCS to visual cortex and control group received sham tDCS. The headache diary was applied for a total of 90days (before, during and after tDCS sessions). Phosphene threshold (PT) induced by transcranial magnetic stimulation was recorded to measure the excitability of the visual cortex before and after each session. RESULTS Step 1 showed higher level of cortical excitability between migraineurs when compared to healthy volunteers; therefore, cathodal tDCS was applied over visual cortex in step 2. After tDCS application, a significant decrease was observed in a number of migraine attacks, painkiller intake and duration of each attack just in experimental group. The analysis of PT indicated no difference in cortical excitability after tDCS. CONCLUSIONS Findings of the study suggested that inhibitory tDCS on visual cortex might be an alternative and non-pharmacological treatment for migraine prophylaxis. However the clinical improvements of patients after tDCS treatment are not correlated with changes in cortical excitability.

Avaliação bayesiana da eficácia da manutenção via processo de renovação generalizado

The Generalized Renewal Process (GRP) is a class of probabilistic models that handles repair actions according to the reduction they provide on the real age of an equipment/system. GRP is an extension of the Renewal Process and Non Homogeneous Poisson Process and it will be used to evaluate repair actions regarding their efficacy degree. Considering that the times between failures follow a Weibull distribution, such an evaluation will be accomplished through the estimation of the GRP parameter distributions and uncertainty analysis on the expected number of failures through Monte Carlo simulation. Due to paucity of failure data, the probabilistic inference procedure will be executed through the Bayesian paradigm which allows for the use of other sources of information, besides the failure data, in the process of estimating the probability distribution on some parameter of interest.

Efficacy of Noninvasive Brain Stimulation on Pain Control in Migraine Patients: A Systematic Review and Meta‐Analysis

To evaluate the efficacy of noninvasive brain stimulation (NIBS) on pain control in migraine patients.

Effects of transcranial direct current stimulation on motor learning in healthy individuals: a systematic review

Introduction Transcranial direct current stimulation (tDCS) has been used to modify cortical excitability and promote motor learning. Objective To systematically review published data to investigate the effects of transcranial direct current stimulation on motor learning in healthy individuals. Methods Randomized or quasi-randomized studies that evaluated the tDCS effects on motor learning were included and the risk of bias was examined by Cochrane Collaboration’s tool. The following electronic databases were used: PubMed, Scopus, Web of Science, LILACS, CINAHL with no language restriction. Results It was found 160 studies; after reading the title and abstract, 17 of those were selected, but just 4 were included. All studies involved healthy, right-handed adults. All studies assessed motor learning by the Jebsen Taylor Test or by the Serial Finger Tapping Task (SFTT). Almost all studies were randomized and all were blinding for participants. Some studies presented differences at SFTT protocol. Conclusion The result is insufficient to draw conclusions if tDCS influences the motor learning. Furthermore, there was significant heterogeneity of the stimulation parameters used. Further researches are needed to investigate the parameters that are more important for motor learning improvement and measure whether the effects are long-lasting or limited in time.