Using a dry electrode EEG device during balance tasks in healthy young-adult males: Test-retest reliability analysis.

BACKGROUND: The analysis of brain activity during balance is an important topic in different fields of science. Given that all measurements involve an error that is caused by different agents, like the instrument, the researcher, or the natural human variability, a test-retest reliability evaluation of the electroencephalographic assessment is a needed starting point. However, there is a lack of information about the reliability of electroencephalographic measurements, especially in a new wireless device with dry electrodes. OBJECTIVE: The current study aims to analyze the reliability of electroencephalographic measurements from a wireless device using dry electrodes during two different balance tests. METHOD: Seventeen healthy male volunteers performed two different static balance tasks on a Biodex Balance Platform: (a) with two feet on the platform and (b) with one foot on the platform. Electroencephalographic data was recorded using Enobio (Neuroelectrics). The mean power spectrum of the alpha band of the central and frontal channels was calculated. Relative and absolute indices of reliability were also calculated. RESULTS: In general terms, the intraclass correlation coefficient (ICC) values of all the assessed channels can be classified as excellent (>0.90). The percentage standard error of measurement oscillated from 0.54% to 1.02% and the percentage smallest real difference ranged from 1.50% to 2.82%. CONCLUSION: Electroencephalographic assessment through an Enobio device during balance tasks has an excellent reliability. However, its utility was not demonstrated because responsiveness was not assessed.

Effects of Transcranial Direct Current Stimulation on Brain Electrical Activity, Heart Rate Variability, and Dual-Task Performance in Healthy and Fibromyalgia Women: A Study Protocol.

People with fibromyalgia could experience physical and cognitive impairments. Furthermore, when performing two tasks at the same time, people with fibromyalgia showed a higher dual-task cost compared to a single task than healthy people. This may result in poorer performance of activities of daily living that are commonly presented as a combination of two or more tasks. Transcranial direct current stimulation (tDCS) is a promising nonpharmacological therapy. However, there is controversy regarding the intensities and the effectiveness of this therapy. Thus, the present study will aim: (1) to compare the effectiveness and the impact of two tDCS intensities (1 mA and 2 mA) on cognitive, motor, brain functions, and cardiac autonomic modulation; (2) to study the impact of tDCS on the dual-task performance and creativity after applying tDCS in dorsolateral prefrontal cortex. In this study, 26 women will participate and will be divided into two groups: women with fibromyalgia (n = 13), and healthy controls (n = 13). A reduction in cognitive-motor interference in dual-task performance is expected, as well as a modification in neurophysiological parameters and an improvement in cardiac autonomic modulation. Lastly, no different effects are expected depending on the stimulation intensity applied. The obtained results will help to determine if tDCS in the dorsolateral prefrontal cortex could improve the occupational performance of women with fibromyalgia.

Neurophysiological Differences Between Women With Fibromyalgia and Healthy Controls During Dual Task: A Pilot Study.

BACKGROUND: Women with FM have a reduced ability to perform two simultaneous tasks. However, the impact of dual task (DT) on the neurophysiological response of women with FM has not been studied. OBJECTIVE: To explore both the neurophysiological response and physical performance of women with FM and healthy controls while performing a DT (motor-cognitive). DESIGN: Cross-sectional study. METHODS: A total of 17 women with FM and 19 age- and sex-matched healthy controls (1:1 ratio) were recruited. The electroencephalographic (EEG) activity was recorded while participants performed two simultaneous tasks: a motor (30 seconds arm-curl test) and a cognitive (remembering three unrelated words). Theta (4-7 Hz), alpha (8-12 Hz), and beta (13-30) frequency bands were analyzed by using EEGLAB. RESULTS: Significant differences were obtained in the healthy control group between single task (ST) and DT in the theta, alpha, and beta frequency bands (p-value < 0.05). Neurophysiological differences between ST and DT were not found in women with FM. In addition, between-group differences were found in the alpha and beta frequency bands between healthy and FM groups, with lower values of beta and alpha in the FM group. Therefore, significant group∗condition interactions were detected in the alpha and beta frequency bands. Regarding physical condition performance, between groups, analyses showed that women with FM obtained significantly worse results in the arm curl test than healthy controls, in both ST and DT. CONCLUSION: Women with FM showed the same electrical brain activity pattern during ST and DT conditions, whereas healthy controls seem to adapt their brain activity to task commitment. This is the first study that investigates the neurophysiological response of women with FM while simultaneously performing a motor and a cognitive task.

Impact of Fibromyalgia on Alpha-2 EEG Power Spectrum in the Resting Condition: A Descriptive Correlational Study.

OBJECTIVE: The objective of this prospective cross-sectional study was to analyze the differences between patients with fibromyalgia and non-pain controls in terms of EEG power in the eyes-closed resting state. This study also aims to evaluate potential correlations between EEG power and subjective pain. METHODS: The fibromyalgia patients were recruited by the Extremadura Association of Fibromyalgia (AFIBROEX) in Cáceres, Spain. Age- and sex-matched healthy controls (1:1 ratio) were recruited from university facilities and people close to the AFIBROEX by public calls. All underwent EEG during a 1-minute resting period with their eyes closed. The theta, alpha-1, alpha-2, beta-1, beta-2, and beta-3 frequency bands were analyzed by using EEGLAB. Self-reported visual analog scale pain scores were determined just prior to EEG. RESULTS: A total of 62 women participated in the study, 31 of them diagnosed with fibromyalgia and 31 healthy controls. Fibromyalgia group exhibited a significantly lower alpha-2 in C4, T3, P4, Pz, and O2 compared to the healthy controls. Interestingly, pain correlated negatively with alpha-2 in Cz, P4, and Pz only in the fibromyalgia group. CONCLUSION: The fibromyalgia group exhibited decrease alpha-2 power in central, temporoparietal, and occipital brain areas. Furthermore, higher values of pain correlated with lower level of alpha-2 power in Cz, P4, and Pz. These findings may point the importance of alpha-2 power in pain in women with fibromyalgia.

Chess Players Increase the Theta Power Spectrum When the Difficulty of the Opponent Increases: An EEG Study.

The present study aimed to analyze differences in the electroencephalogram (EEG) power spectrum (theta, alpha, and beta) between participants who won (winning group) and those who lost (losing group) in three different chess games: against their same Elo (100% chess games), 25% over their Elo (125% chess games), and 25% under their Elo (75% chess games). EEG was assessed at baseline and during the chess games. Method: 14 male chess players (age: 35.36 ± 13.77 and Elo: 1921 ± 170) played three games of 3 min, plus two additional seconds per move, while EEG was assessed. There were three difficulty levels (75%, 100%, and 125%), with two games (one with white pieces and another with black pieces) per level. The winning group showed higher theta power in the frontal, central, and posterior brain regions when difficulty increased (p-value <0.05). Besides this, alpha power showed higher values (p-value <0.05) in 125% games than in 75% chess games in C3, T3, T4, T5, and T6. The losing group showed a significant decrease (p-value <0.05) in the beta and alpha power spectrum in frontal, central, parietotemporal, and occipital areas, when the opponent's difficulty increased. Moreover, between groups, analyses showed higher theta power in the losing group than in the winning group, in C3, T5, T6, P4, and Pz (p-value <0.05). Therefore, the winning group was able to adapt to each difficulty level, increasing theta power in the frontal, central, and posterior brain areas, as the efficiency hypothesis postulated. These changes were not observed in the losing group. Moreover, increases in alpha power during the most difficult games, in comparison with the easier, could have been caused by creative ideation and divergent thinking, as participants looked for alternative solutions against a higher-skilled opponent.

Electroencephalographic response of chess players in decision-making processes under time pressure.

The game of chess offers an enabling environment for the study of basic cognitive decision making processes where different types of memories are involved. The aim of the present study was to describe and compare the brain electrical activity pattern of chess players in two different situations under time pressure to make the move: rapid, 15 min, plus 10 s additional time per move and lightning, a one-minute game. Thus, lightning game offers an appropriate environment to isolate memory chunks and rapid game will offer the perspective of a working memory task. Encephalogram (EEG) recordings were obtained while a total of 14 male chess players (age: 35.36 ±â€¯13.77 and ELO: 1921.07 ±â€¯170.67) played lightning and rapid chess games. Results indicate that different activity patterns between the rapid and the lightning games were found. Increments in theta power during lightning game in posterior regions could indicate that theta power might be related with chunks retrieval. Moreover, right hemisphere is more activated in chess games, probably caused by visuospatial processing. These brain patterns characterizations could be useful for chess training or clinicians in the field of neuroscience.