Examinando por Autor "Iglesias-Soler, Eliseo"

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An Integrative Clustering Approach to tDCS Individual Response Variability in Cognitive Performance: Beyond a Null Effect on Working Memory
(PERGAMON-ELSEVIER SCIENCE LTD, 2020-07-28) Luque-Casado, Antonio; Rodríguez-Freiría, Rocio; Fogelson, Noa; Iglesias-Soler, Eliseo; Fernandez-del-Olmo, Miguel
Despite the growing interest in the use of transcranial direct current stimulation (tDCS) for the modulation of human cognitive function, there are contradictory findings regarding the cognitive benefits of this technique. Inter-individual response variability to tDCS may play a significant role. We explored the effects of anodal versus sham tDCS over the left prefrontal cortex (LPFC) on working memory performance, taking into account the inter-individual variability. Twenty-nine healthy volunteers received an 'offline' anodal tDCS (1.5 mA, 15 min) to the left prefrontal cortex (F3 electrode site) in an intra-individual, cross-over, sham-controlled experimental design. n-back and Sternberg task performance was assessed before (baseline), immediately after tDCS administration (T1) and 5 min post-T1 (T2). We applied an integrative clustering approach to characterize both the group and individual responses to tDCS, as well as identifying naturally occurring subgroups that may be present within the total sample. Anodal tDCS failed to improve working memory performance in the total sample. Cluster analysis identified a subgroup of 'responders' who significantly improved their performance after anodal (vs. sham) stimulation, although not to a greater extent than the best baseline or sham condition. The proportion of 'responders' ranged from 15% to 59% across task conditions and behavioral outputs. Our findings show a high inter-individual variability of the tDCS response, suggesting that the use of tCDS may not be an effective tool to improve working memory performance in healthy subjects. We propose that the use of clustering methods is more suitable in identifying 'responders' and for evaluating the efficacy of this technique.
Events and event records (scoring and penalties) across temporal units in elite judo contests: implications for tactical preparation
(Revista de Artes Marciales Asiáticas, 2024-11-01) Dopico-Calvo, Xurxo; Santos, Luis; Carbelleira, Eduardo; Mayo, Xián; Ceylan, Bayram; Simenko, Jozef; Sevilla-Sánchez, Marta; Iglesias-Soler, Eliseo
Introduction: This study examines the distribution of events and event records (EVRs) in elite judo competitions, encompassing both male and female categories. Sample: By analyzing data from the 2018, 2019, and 2021 World Championships, the study incorporates 6487 events (EVs) and 2340 contests classified by their last event (cEV). Results: The predominant occurrence of EV2 and EV3 in male (23.2% and 36.6%) and female (26.8% and 31.7%) contests suggests consistent patterns. Statistical analyses reveal non-uniform distributions of events within temporal units (TUs). Small associations were found between EVRs and TUs for EV1, EV2 and EV3 (Cramer’s V = 0.103 to 0.171; p<0.001), while moderate associations were observed for EV4 (Cramer’s V = 0.260 to 0.271; p<0.001) with no associations detected for EV5 and EV6, in both sexes. Female contests generally feature fewer events, concentrated within the same TU, indicating shorter durations compared to males. The study emphasizes the association between the occurrence of EVRs and the moment they occur, demonstrating similar patterns across sexes. Waza-ari was significantly overrepresented in the TU1 for both males and females (SR = 2.1 and 2.2, respectively). In contrast, Ippon was overrepresented in the Golden Score (TU-GS) period (SR = 3.3) for males. Notably, cEV1, cEV2, and cEV3 exhibit timing variations between male and female categories, while cEV4 share equivalent timing. Conclusion: This research provides comprehensive insights into the dynamics of elite judo contests, informing professionals on the nuanced strategies needed for male and female judo athletes. The observed tendency of athletes to adopt an offensive approach at the beginning of contests, focusing on throws or body controls in groundwork over penalizations, adds a valuable layer to understanding the competitive dynamics in judo.
Exploring the effects of Transcranial Direct Current Stimulation over the prefrontal cortex on working memory: A cluster analysis approach
(ELSEVIER IRELAND LTD, 2019-08-06) Luque-Casado, Antonio; Fogelson, Noa; Iglesias-Soler, Eliseo; Fernandez-del-Olmo, Miguel
BACKGROUND: The interest in the use of anodal transcranial direct current stimulation (tDCS) for the enhancement of cognitive functioning has increased significantly in recent years. However, the efficacy of this technique remains to be established. OBJECTIVE: The current study explored the effects of anodal vs. sham tDCS over the left dorsolateral prefrontal cortex (DLPFC) during the performance of the digit span backwards task. METHODS: 30 healthy participants received 'offline' anodal tDCS (1.5 mA, 15 min) to the left DLPFC in an intra-individual, cross-over, sham-controlled experimental design. Memory span performance was assessed before (baseline), immediately after tDCS administration (T1) and 10 min post-T1 (T2). We applied cluster analysis in order to characterize individual responses to tDCS, and in order to identify naturally occurring subgroups that may be present. RESULTS: Analysis of all the subjects showed that anodal tDCS failed to improve memory span performance. Cluster analysis revealed the presence of a subgroup of 'responders' that significantly improved their performance after anodal (vs. sham) tDCS in T1 (47%) and T2 (46%). However, there was no significant improvement in performance after anodal tDCS compared to the best baseline performance. CONCLUSION: Our findings suggest that tDCS does not improve memory span performance and highlights the need for better ways to optimize methodological approaches in order to account for inter-individual variability and accurately assess the evidential value of tDCS-linked cognitive outcomes.
Small Enhancement of Bimanual Typing Performance after 20 Sessions of tDCS in Healthy Young Adults
(PERGAMON-ELSEVIER SCIENCE LTD, 2021-05-08) Sevilla-Sánchez, Marta; Hortobágyi, Tibor; Fogelson, Noa; Iglesias-Soler, Eliseo; Carballeira, Eduardo; Fernandez-del-Olmo, Miguel
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that may improve motor learning. However, the long-term effects of tDCS have not been explored, and the ecological validity of the evaluated tasks was limited. To determine whether 20 sessions of tDCS over the primary motor cortex (M1) would enhance the performance of a complex life motor skill, i.e., typing, in healthy young adults. Healthy young adults (n = 60) were semi-randomly assigned to three groups: the tDCS group (n = 20) received anodal tDCS over M1; the SHAM group (n = 20) received sham tDCS, both while performing a typing task; and the Control group (CON, n = 20) only performed the typing task. Typing speed and errors at maximum (mTT) and submaximal (iTT) speeds were measured before training, and after 10 and 20 sessions of tDCS. Every subject increased maximum typing speed after 10 and 20 tDCS sessions, with no significant differences (p > 0.05) between the groups. The number of errors at submaximal rates decreased significantly (p < 0.05) by 4% after 10 tDCS sessions compared with the 3% increase in the SHAM and the 2% increase in the CON groups. Between the 10th and 20th tDCS sessions, the number of typing errors increased significantly in all groups. While anodal tDCS reduced typing errors marginally, such performance-enhancing effects plateaued after 10 sessions without any further improvements in typing speed. These findings suggest that long-term tDCS may not have functionally relevant effects on healthy young adults' typing performance.
The penalties and scores by events, to predict victory and defeat according to when the contest ends in elite judo contests
(Universidad de León, 2004-07-01) Dopico-Calvo, Xurxo; Santos, Luis; Mayo, Xián; Carballeira, Eduardo; Clavel, Iván; Ceylan, Bayram; Kons, Rafael Lima; Iglesias-Soler, Eliseo
The main aim of this study was to ascertain whether the victory and defeat in the different types of the judo contest, in the elite male and female divisions, are associated to the occurrence of the penalties and scores of the first three events (changes in the scoreboard -either penalty or score-) of them. 2340 contests of the 2018, 2019 and 2021 World Judo Championships were analysed. The Pearson’s chi-squared test expressed that [1] shido-1 in the first event (EV1) of the contests that end before the regular time (BRT) and of those without considering when they end (OC) is associated to defeat for both sexes and, that [2] wazari-1 in the EV1 of the BRT and in the EV2 and EV3 of the BRT, of the contests with the duration extended beyond the regular time (EXT) and of OC is associated to victory for both sexes except in the EV2 of the EXT (only for male athletes in this case). Thus, it is suggested that the victory and defeat in the different types of the judo elite contests are associated with the occurrence of the penalties and scores of the first three events of them.