Effective brain connectivity related to non-painful thermal stimuli using EEG.

Understanding the brain response to thermal stimuli is crucial in the sensory experience. This study focuses on non-painful thermal stimuli, which are sensations induced by temperature changes without causing discomfort. These stimuli are transmitted to the central nervous system through specific nerve fibers and are processed in various regions of the brain, including the insular cortex, the prefrontal cortex, and anterior cingulate cortex. Despite the prevalence of studies on painful stimuli, non-painful thermal stimuli have been less explored. This research aims to bridge this gap by investigating brain functional connectivity during the perception of non-painful warm and cold stimuli using electroencephalography (EEG) and the partial directed coherence technique (PDC). Our results demonstrate a clear contrast in the direction of information flow between warm and cold stimuli, particularly in the theta and alpha frequency bands, mainly in frontal and temporal regions. The use of PDC highlights the complexity of brain connectivity during these stimuli and reinforces the existence of different pathways in the brain to process different types of non-painful warm and cold stimuli.

Production of rGO-Based Electrospinning Nanocomposites Incorporated in Recycled PET as an Alternative Dry Electrode.

In this work, Coca-Cola® bottles were reused as a PET polymer (rPET) source to produce electrospun polymeric nanofibers. The nanofibers were electrospun from polymer solutions with different concentrations of reduced graphene oxide (rGO) incorporated for applications in somatosensory electrical stimulation. The rPET/rGO nanofiber mats were characterized by SEM, TEM, Raman, DSC, TGA, and DMA and the results showed that the incorporation of rGO in electrospun rPET fibers produced rPET/rGO composites. The rPET/rGO composites were then evaluated for possible application as dry electrodes. Moreover, with a preliminary test of numerous volunteers, the rPET/rGO dry electrode showed promising results. The rPET/rGO electrodes showed good performance and applicability to make dry electrodes, and these have applications as dry or wearable electrodes to produce electrochemical sensors.

Classification of Complex Emotions Using EEG and Virtual Environment: Proof of Concept and Therapeutic Implication.

During the last decades, neurofeedback training for emotional self-regulation has received significant attention from scientific and clinical communities. Most studies have investigated emotions using functional magnetic resonance imaging (fMRI), including the real-time application in neurofeedback training. However, the electroencephalogram (EEG) is a more suitable tool for therapeutic application. Our study aims at establishing a method to classify discrete complex emotions (e.g., tenderness and anguish) elicited through a near-immersive scenario that can be later used for EEG-neurofeedback. EEG-based affective computing studies have mainly focused on emotion classification based on dimensions, commonly using passive elicitation through single-modality stimuli. Here, we integrated both passive and active elicitation methods. We recorded electrophysiological data during emotion-evoking trials, combining emotional self-induction with a multimodal virtual environment. We extracted correlational and time-frequency features, including frontal-alpha asymmetry (FAA), using Complex Morlet Wavelet convolution. Thinking about future real-time applications, we performed within-subject classification using 1-s windows as samples and we applied trial-specific cross-validation. We opted for a traditional machine-learning classifier with low computational complexity and sufficient validation in online settings, the Support Vector Machine. Results of individual-based cross-validation using the whole feature sets showed considerable between-subject variability. The individual accuracies ranged from 59.2 to 92.9% using time-frequency/FAA and 62.4 to 92.4% using correlational features. We found that features of the temporal, occipital, and left-frontal channels were the most discriminative between the two emotions. Our results show that the suggested pipeline is suitable for individual-based classification of discrete emotions, paving the way for future personalized EEG-neurofeedback training.

Characterization of interstimulus interaction in the multiple auditory steady-state responses at high sound levels.

Multiple auditory steady-state response (MASSR) is recommended to estimate hearing thresholds in difficult-to-test individuals. The multiple stimuli that evoke MASSR may present an interstimulus interaction (ISI) that is able to distort the generation of responses. No consensus exists on the effects of the ISI in MASSR when dealing with high sound level stimuli or cases of sensorineural hearing loss. This study investigated the effects of ISI on the amplitude and detectability of auditory steady-state responses, with a focus at and above 65 dB sound pressure level (SPL). Normal hearing (NH) and sensorineural hearing impaired (SNHI) adults were tested with different stimulus types [amplitude modulation (AM) One octave chirp (OC), and a weighted OC (WOC)], stimulus levels, and modalities (single or multiple stimuli). ISI typically attenuated response amplitude of a control stimulus caused by an interference stimulus one octave above the control stimulus. At and above 80 dB SPL, attenuations of around 50% decreased the number of detectable responses near SNHI thresholds, especially for OC and WOC. AM stimuli obtained a higher detection rate than OC and WOC when presented 10 dB above the behavioral hearing threshold of SNHI participants. Using OC in MASSR when assessing elevated thresholds might diminish accuracy on threshold estimation, and extend test duration.

A bayesian approach to the spectral F-Test: Application to auditory steady-state responses.

BACKGROUND AND OBJECTIVE: Auditory steady-state responses (ASSRs) represent an objective method used in clinical practice to assess hearing thresholds. The steady-state nature of these signals allows response detection by means of statistical techniques in the frequency domain as spectral F-test. This objective response detection (ORD) compares the power of the response bin against the power of the neighboring frequency noise bins. Most ORD algorithms are based on the Neyman-Pearson approach to the hypothesis test provided that the likelihood ratio test is the most powerful test for a given significance level alpha (also called Type I error). On the other hand, the Bayesian approach allows the inclusion of prior information in the model and enables the updating of this information with posterior knowledge. This approach, however, has not been explored with respect to ORD techniques, thus enabling the exploration of new paradigms, which may contribute to this field of study, especially in terms of the time required for response detection. The aim of this study is to use the Bayesian approach in the implementation of the spectral F-test for application to ASSRs. METHODS: Monte Carlo simulations were performed to evaluate Neyman-Pearson and Bayesian detectors' performances with the spectral F-test as a function of the signal-to-noise ratio. Then, the two detectors were applied to ASSR recordings of nine normal-hearing individuals subjected to amplitude-modulated tones of various intensities. RESULTS: Both simulation and ASSR data analyses showed that among the scenarios analyzed, the most promising case was that in which the lowest possible values for the a priori probability were selected for the null hypothesis (H0), allowing detection at low signal-to-noise ratios. The worst performance occurred when the a priori probabilities for both hypotheses were equal. The ASSR data also showed that higher stimulus intensity led to better performance and faster detection due to improvements in the signal-to-noise ratio. CONCLUSIONS: The a priori probabilities can affect the Bayesian detector's performance, directly impacting the time needed to identify responses. The parallel behaviors observed between the performances of both approaches showed that the Bayesian detector can achieve its ideal performance at lower signal-to-noise ratios compared to the optimal performance of the Neyman-Pearson detector, reflecting the promising applicability of the Bayesian approach to evoked potentials.

Emotion Regulation Using Virtual Environments and Real-Time fMRI Neurofeedback.

Neurofeedback (NFB) enables the voluntary regulation of brain activity, with promising applications to enhance and recover emotion and cognitive processes, and their underlying neurobiology. It remains unclear whether NFB can be used to aid and sustain complex emotions, with ecological validity implications. We provide a technical proof of concept of a novel real-time functional magnetic resonance imaging (rtfMRI) NFB procedure. Using rtfMRI-NFB, we enabled participants to voluntarily enhance their own neural activity while they experienced complex emotions. The rtfMRI-NFB software (FRIEND Engine) was adapted to provide a virtual environment as brain computer interface (BCI) and musical excerpts to induce two emotions (tenderness and anguish), aided by participants' preferred personalized strategies to maximize the intensity of these emotions. Eight participants from two experimental sites performed rtfMRI-NFB on two consecutive days in a counterbalanced design. On one day, rtfMRI-NFB was delivered to participants using a region of interest (ROI) method, while on the other day using a support vector machine (SVM) classifier. Our multimodal VR/NFB approach was technically feasible and robust as a method for real-time measurement of the neural correlates of complex emotional states and their voluntary modulation. Guided by the color changes of the virtual environment BCI during rtfMRI-NFB, participants successfully increased in real time, the activity of the septo-hypothalamic area and the amygdala during the ROI based rtfMRI-NFB, and successfully evoked distributed patterns of brain activity classified as tenderness and anguish during SVM-based rtfMRI-NFB. Offline fMRI analyses confirmed that during tenderness rtfMRI-NFB conditions, participants recruited the septo-hypothalamic area and other regions ascribed to social affiliative emotions (medial frontal / temporal pole and precuneus). During anguish rtfMRI-NFB conditions, participants recruited the amygdala and other dorsolateral prefrontal and additional regions associated with negative affect. These findings were robust and were demonstrable at the individual subject level, and were reflected in self-reported emotion intensity during rtfMRI-NFB, being observed with both ROI and SVM methods and across the two sites. Our multimodal VR/rtfMRI-NFB protocol provides an engaging tool for brain-based interventions to enhance emotional states in healthy subjects and may find applications in clinical conditions associated with anxiety, stress and impaired empathy among others.

Influence of functional task-oriented mental practice on the gait of transtibial amputees: a randomized, clinical trial.

BACKGROUND: Mental practice (MP) through motor imagery is a cognitive training strategy used to improve locomotor skills during rehabilitation programs. Recent works have used MP tasks to investigate the neurophysiology of human gait; however, its effect on functional performance has not been evaluated. In the present study, the influence of gait-oriented MP tasks on the rehabilitation process of gait in transtibial amputees was investigated by assessing the vertical (V), anterior-posterior (AP), and medio-lateral (ML) ground reaction forces (GRFs) and the time duration of the support phase of the prosthetic limb. METHODS: Unilateral transtibial amputees, who were capable of performing motor imagination tasks (MIQ-RS score ≥4), were randomly divided into two groups: Group A (n = 10), who performed functional gait-oriented MP combined with gait training, and Group B (n = 5), who performed non-motor task MP. The MP intervention was performed in the first-person perspective for 40 min, 3 times/week, for 4 weeks. The GRF outcome measures were recorded by a force platform to evaluate gait performance during 4 distinct stages: at baseline (BL), 1 month before the MP session; Pre-MP, 1-3 days before the MP session; Post-MP, 1-3 days after the MP session; and follow-up (FU), 1 month after MP session. The gait variables were compared inter- and intra-group by applying the Mann-Whitney and Friedman tests (alpha = 0.05). RESULTS: All volunteers exhibited a homogenous gait pattern prior to MP intervention, with no gait improvement during the BL and Pre-MP stages. Only Group A showed significant improvements in gait performance after the intervention, with enhanced impact absorption, as indicated by decreased first V and AP peaks; propulsion capacity, indicated by increasing second V and AP peaks; and balance control of the prosthetic limb, indicated by decreasing ML peaks and increasing duration of support. This gait pattern persisted until the FU stage. CONCLUSIONS: MP combined with gait training allowed transtibial amputees to reestablish independent locomotion. Since the effects of MP were preserved after 1 month, the improvement is considered related to the specificity of the MP tasks. Therefore, MP may improve the clinical aspect of gait rehabilitation when included in a training program.

Assessment of frequency specific auditory steady-state response using amplitude modulation with 2-order exponential envelope.

This study investigated the performance of Frequency Specific Auditory Steady-State Response (FS-ASSR) detection elicited by the amplitude modulated tone with 2-order exponential envelope (AM2), using objective response detection (ORD) techniques of Spectral F-Test (SFT) and Magnitude Squared Coherence (MSC). ASSRs from 24 normal hearing adults were obtained during binaural multi-tone stimulation of amplitude-modulation (AM) and AM2 at intensities of 60, 45 and 30 dBSPL. The carrier frequencies were 500, 1000, 2000, and 4000 Hz, modulated between 77 and 105 Hz. AM2 achieve FS-ASSR amplitudes higher than AM by 16%, 18% and 12% at 60, 45 and 30 dBSPL, respectively, with a major increase at 500 Hz (22.5%). AMS2PL increased the Detection Rate (DR) up to 8.3% at 500 Hz for 30 dBSPL, which is particularly beneficial for FS-ASSR detection near the hearing threshold. In addition, responses in 1000 and 4000 Hz were consistently increased. The MSC and SFT presented no differences in Detection Rate (DR). False Detection Rate (FDR) was close to 5% for both techniques and tones. Detection times to reach DR over 90% were 3.5 and 4.9 min at 60 and 45 dBSPL, respectively. Further investigation concerning efficient multiple FS-ASSR is still necessary, such as testing subjects with hearing loss.

Detection of movement intention using EEG in a human-robot interaction environment

Introduction : This paper presents a detection method for upper limb movement intention as part of a brain-machine interface using EEG signals, whose final goal is to assist disabled or vulnerable people with activities of daily living. Methods EEG signals were recorded from six naïve healthy volunteers while performing a motor task. Every volunteer remained in an acoustically isolated recording room. The robot was placed in front of the volunteers such that it seemed to be a mirror of their right arm, emulating a Brain Machine Interface environment. The volunteers were seated in an armchair throughout the experiment, outside the reaching area of the robot to guarantee safety. Three conditions are studied: observation, execution, and imagery of right arm’s flexion and extension movements paced by an anthropomorphic manipulator robot. The detector of movement intention uses the spectral F test for discrimination of conditions and uses as feature the desynchronization patterns found on the volunteers. Using a detector provides an objective method to acknowledge for the occurrence of movement intention. Results When using four realizations of the task, detection rates ranging from 53 to 97% were found in five of the volunteers when the movement was executed, in three of them when the movement was imagined, and in two of them when the movement was observed. Conclusions Detection rates for movement observation raises the question of how the visual feedback may affect the performance of a working brain-machine interface, posing another challenge for the upcoming interface implementation. Future developments will focus on the improvement of feature extraction and detection accuracy for movement intention using EEG data.

Auditory steady-state responses in school-aged children: a pilot study.

BACKGROUND: The use of Auditory Steady-State Responses (ASSRs) for auditory screening in school-aged children, particularly in children who are difficult to test and children with disabilities, has not been explored yet. This pilot study investigated the use of ASSR for auditory screening in school-aged children. MATERIALS AND METHODS: A cross-sectional pilot study of 23 children aged 9 to 11 with normal-hearing thresholds and seven age-matched children with permanent moderate-to-profound bilateral hearing loss were examined. The tested carrier frequencies were 500, 1,000, 2,000, and 4,000 Hz, and the stimulus was modulated between 77 and 107 Hz. The ASSRs decreased according to the tested intensity levels of 50, 40, and 30 dB sound pressure level (SPL). Sensitivity and specificity were estimated from the responses of the children with normal hearing and those with hearing loss. RESULTS: For the children with normal hearing, the 2,000-Hz frequency was detected more often in both ears and at all intensity levels compared to the other frequencies. The 500- and 2,000-Hz frequencies resulted in different response patterns in both ears. The time until response detection increased in parallel with amplitude reduction, as expected. The overall time required for the test was 15 minutes, including the time spent in volunteer preparation. The sensitivity was 97% for the three intensities, and the best specificity value was 100%, which was observed at 50 dB. DISCUSSION: The response analysis indicated that a screening protocol for school-aged children could include 1,000, 2,000, and 4,000 Hz and that the recording of ASSRs was highly sensitive to internal and external factors. Fifty dB SPL should be considered a cut-off criterion for screening purposes because this was the intensity level with a sensitivity of 97% and a specificity of 100%. CONCLUSION: The use of ASSRs might be particularly useful in school-aged children who have difficulty performing subjective hearing tests. The sensitivity and specificity data suggested that the use of ASSRs was feasible as an auditory screening tool. In order to determine a protocol for screening, future studies should include a larger sample and children with mild hearing loss.

The addition of functional task-oriented mental practice to conventional physical therapy improves motor skills in daily functions after stroke

BACKGROUND: Mental practice (MP) is a cognitive strategy which may improve the acquisition of motor skills and functional performance of athletes and individuals with neurological injuries. OBJECTIVE: To determine whether an individualized, specific functional task-oriented MP, when added to conventional physical therapy (PT), promoted better learning of motor skills in daily functions in individuals with chronic stroke (13±6.5 months post-stroke). METHOD: Nine individuals with stable mild and moderate upper limb impairments participated, by employing an A1-B-A2 single-case design. Phases A1 and A2 included one month of conventional PT, and phase B the addition of MP training to PT. The motor activity log (MAL-Brazil) was used to assess the amount of use (AOU) and quality of movement (QOM) of the paretic upper limb; the revised motor imagery questionnaire (MIQ-RS) to assess the abilities in kinesthetic and visual motor imagery; the Minnesota manual dexterity test to assess manual dexterity; and gait speed to assess mobility. RESULTS: After phase A1, no significant changes were observed for any of the outcome measures. However, after phase B, significant improvements were observed for the MAL, AOU and QOM scores (p<0.0001), and MIQ-RS kinesthetic and visual scores (p=0.003; p=0.007, respectively). The significant gains in manual dexterity (p=0.002) and gait speed (p=0.019) were maintained after phase A2. CONCLUSIONS: Specific functional task-oriented MP, when added to conventional PT, led to improvements in motor imagery abilities combined with increases in the AOU and QOM in daily functions, manual dexterity, and gait speed. .

Contribution of Galvanic Vestibular Stimulation for the Diagnosis of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis.

BACKGROUND AND PURPOSE: Galvanic vestibular stimulation (GVS) is a low-cost and safe examination for testing the vestibulospinal pathway. Human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a slowly progressive disease that affects the vestibulospinal tract early in its course. This study compared the electromyographic (EMG) responses triggered by GVS of asymptomatic HTLV-1-infected subjects and subjects with HAM/TSP. METHODS: Bipolar galvanic stimuli (400 ms and 2 mA) were applied to the mastoid processes of 39 subjects (n=120 stimulations per subject, with 60 from each lower limb). Both the short latency (SL) and medium latency (ML) components of the EMG response were recorded from the soleus muscles of 13 healthy, HTLV-1-negative adults (56±5 years, mean±SD), and 26 individuals infected with HTLV-1, of whom 13 were asymptomatic (56±8 years) and 13 had HAM/TSP (60±6 years). RESULTS: The SL and ML EMG components were 55±4 and 112±10 ms, respectively, in the group of healthy subjects, 61±6 and 112±10 ms and in the HTLV-1-asymptomatic group, and 67±8 and 130±3 ms in the HAM/TSP group (p=0.001). The SL component was delayed in 4/13 (31%) of the examinations in the HTLV-1-asymptomatic group, while the ML component was normal in all of them. In the HAM/TSP group, the most common alteration was the absence of waves. CONCLUSIONS: A pattern of abnormal vestibular-evoked EMG responses was found in HTLV-1-neurological disease, ranging from delayed latency among asymptomatic carriers to the absence of a response in HAM/TSP. GVS may contribute to the early diagnosis and monitoring of nontraumatic myelopathies.

The addition of functional task-oriented mental practice to conventional physical therapy improves motor skills in daily functions after stroke.

BACKGROUND: Mental practice (MP) is a cognitive strategy which may improve the acquisition of motor skills and functional performance of athletes and individuals with neurological injuries. OBJECTIVE: To determine whether an individualized, specific functional task-oriented MP, when added to conventional physical therapy (PT), promoted better learning of motor skills in daily functions in individuals with chronic stroke (13 ± 6.5 months post-stroke). METHOD: Nine individuals with stable mild and moderate upper limb impairments participated, by employing an A1-B-A2 single-case design. Phases A1 and A2 included one month of conventional PT, and phase B the addition of MP training to PT. The motor activity log (MAL-Brazil) was used to assess the amount of use (AOU) and quality of movement (QOM) of the paretic upper limb; the revised motor imagery questionnaire (MIQ-RS) to assess the abilities in kinesthetic and visual motor imagery; the Minnesota manual dexterity test to assess manual dexterity; and gait speed to assess mobility. RESULTS: After phase A1, no significant changes were observed for any of the outcome measures. However, after phase B, significant improvements were observed for the MAL, AOU and QOM scores (p<0.0001), and MIQ-RS kinesthetic and visual scores (p=0.003; p=0.007, respectively). The significant gains in manual dexterity (p=0.002) and gait speed (p=0.019) were maintained after phase A2. CONCLUSIONS: Specific functional task-oriented MP, when added to conventional PT, led to improvements in motor imagery abilities combined with increases in the AOU and QOM in daily functions, manual dexterity, and gait speed.

An open-source, FireWire camera-based, Labview-controlled image acquisition system for automated, dynamic pupillometry and blink detection.

The dynamic, accurate measurement of pupil size is extremely valuable for studying a large number of neuronal functions and dysfunctions. Despite tremendous and well-documented progress in image processing techniques for estimating pupil parameters, comparatively little work has been reported on practical hardware issues involved in designing image acquisition systems for pupil analysis. Here, we describe and validate the basic features of such a system which is based on a relatively compact, off-the-shelf, low-cost FireWire digital camera. We successfully implemented two configurable modes of video record: a continuous mode and an event-triggered mode. The interoperability of the whole system is guaranteed by a set of modular software components hosted on a personal computer and written in Labview. An offline analysis suite of image processing algorithms for automatically estimating pupillary and eyelid parameters were assessed using data obtained in human subjects. Our benchmark results show that such measurements can be done in a temporally precise way at a sampling frequency of up to 120 Hz and with an estimated maximum spatial resolution of 0.03 mm. Our software is made available free of charge to the scientific community, allowing end users to either use the software as is or modify it to suit their own needs.

Current perception threshold and reaction time in the assessment of sensory peripheral nerve fibers through sinusoidal electrical stimulation at different frequencies

INTRODUCTION: The Perception Sensory Threshold (ST) for sinusoidal current stimuli at 5, 250, and 2,000 Hz is commonly used in the assessment of peripheral nerve fibers (C, Aδ, and Aβ, respectively). However, the neuroselectivity of these frequencies is far from consensus. In addition, Reaction Time (RT) measurements suggest that 2,000 Hz stimuli excite Aβ-fibers, 250 Hz Aβ- or Aδ-fibers, as well as 5 Hz Aβ-, Aδ- or C-fibers. Therefore, we suppose that the sinusoidal current neuroselectivity may be better observed if ST and RT parameters are jointly evaluated. In addition, we have investigated whether there are other sets of frequencies that could be used. METHODS: Thus this work investigates ST and RT for stimuli with frequency ranging from 1 to 3,000 Hz, on 28 healthy subjects aged from 19 to 44 years old (27.1±5.49). ST and RT dissimilarity among different frequencies was evaluated applying bi-dimensional Fisher Quadratic Discriminant. RESULTS: The lowest classification error (3.6%) was obtained for 1, 250, and 3,000 Hz. Error for 5, 250, and 2,000Hz was 16.7%. Stimulation frequency at 1 Hz evoked more sensations related to C-fibers (53% of reports) than to Aβ-fibers (36%). However, this behavior did not repeat itself at 5 Hz (only 21% of perceptions were related to C-fibers against 64% to Aβ-fibers). Sensations related to Aβ-fibers prevailed for the highest frequencies presented to the subjects (2,000 Hz - 82% and 3,000 Hz - 93%). Mean RT values showed a decreasing trend with frequency. CONCLUSION: These results suggest that frequencies 1, 250, and 3,000 Hz are more neuroselective than 5, 250, and 2,000 Hz for the evaluation of peripheral sensitive fibers. Furthermore, they show RT usefulness.

Equipamento portátil para ensaios simultâneos de teste de vigilância psicomotora e pupilometria / Portable equipment for simultaneous assays of psychomotor vigilance test and pupillometry

Neste artigo é descrito um sistema com potencial para identificar a privação do sono, que, com base no levantamento bibliográfico realizado, ainda não foi abordado na literatura. Este sistema integra simultaneamente duas metodologias, o teste de vigilância psicomotora (Psychomotor vigilance test, PVT) e a pupilometria, que se destacam no estudo da privação do sono. Entretanto, para atender às peculiaridades destas metodologias, permitindo que coexistam em um único sistema, algumas adaptações foram realizadas em seus procedimentos. Esta integração poderá garantir não só a complementariedade de indicadores que torna a identificação da privação do sono mais robusta, assim como estabelecer a equalização do estado psicofisiológico do sujeito, o que não é possível em testes realizados com defasagem temporal. Neste estudo, a validação das métricas do sistema foi realizada com sujeitos em estado de alerta. Os resultados mostraram-se coerentes com a literatura. Entretanto, algumas métricas apresentam um deslocamento em seus valores médios, que segundo as avaliações realizadas são determinadas pelas exigências técnicas do sistema. Os resultados obtidos nesta avaliação, somados à crescente demanda de ferramentas de aplicação em larga escala e que possam ser utilizadas além dos limites laboratoriais para estudos em distúrbios e privação do sono, apontam este sistema como uma potencial ferramenta. Entretanto, será necessário o estabelecimento de um experimento rigoroso, para avaliar se os indicadores oriundos das métricas do sistema permitem a identificação robusta da privação do sono.

This paper describes a system with potential for identification of sleep deprivation, which, based on our bibliographical survey, has not yet been described in the literature. The system combines two methodologies, i. e., Psychomotor vigilance test (PVT) and pupillometry, which are among the leading methods for the study of sleep deprivation. However, due to peculiarities of both methodologies, some adaptations were made in their procedures to allow them to co-exist in the same system. Such integration may not only ensure the complementarity of indexes, making the identification of sleep deprivation more solid, but also set up the equalization of the subject's psycho-physiological state, which is not possible in tests performed with a time lag. In this study, the performance of measurements provided by the system was assessed in subjects on alert. However, some measurements present a displacement with respect to their average values, which, according to assessment, are determined by system's technical requirements. The results obtained in this assessment, combined with the increasing demand for large scale application tools, able to be used outside the limits of the laboratory environment for studies in sleep deprivation disorders, point to this system as a potential tool. However, the undertaking of a rigorous experiment is necessary to assess whether the indexes obtained by the system allow the robust identification of sleep deprivation.

Evidências preliminares da efetividade do treinamento cognitivo para melhorar a inteligência de crianças escolares / Preliminary evidence of effectiveness in cognitive training to improve school children intelligence

Objetivou-se verificar a efetividade de um programa de treinamento cognitivo (TC) para melhorar a inteligência de crianças escolares. Participaram do TC 16 crianças (M = 8,75 anos; DP = 0,44) divididas em grupo controle (GC) e grupo experimental (GE), avaliadas no pré e no pós-teste com medidas de inteligência fluida, cristalizada e desempenho escolar. O TC consistiu da aplicação de tarefas de memória de trabalho por dois meses. Não foram encontradas diferenças significativas entre as medidas pré e pós-teste de inteligência. Entretanto, após o treinamento, observou-se redução das diferenças entre Gc e Gf em medidas de inteligência fluída. No caso do teste Raven, a diferença entre GC e GE (favorável a GC) caiu de um d = 0,126 para d = 0,058. No teste TNVRI a diferença inicial a favor de GC (d = 0, 177) passou a ser negativa (d = -0,384), portanto a favor de GE. Esse pequeno benefício não foi observado nos testes de conhecimento escolar, nos quais os maiores ganhos no pós-teste foram do GC. Os resultados encontram suporte parcial na literatura. Contudo, estudos com uma amostra maior, maior tempo de treinamento e de intervalo entre os pós-testes são necessários para verificar a generalidade de tais achados.(AU)

The present research intends to verify the effectiveness of a cognitive training (CT) to foster intelligence of school Brazilian children from different intellectual levels. Sixteen fourth-grade boys (M = 8.75 years; SD = .44) took part in this study and were randomly selected to the training group (TG) or control group (CG). In the pre and posttest, all children were assessed using measures with measures of fluid, crystallized intelligence, and school achievement. For the training program we used working memory task for a period of two months. Results: no statically significant difference was found between both groups at posttest in none of the measures used. However, after training, there was a reduction of the differences between GC and GF on measures of fluid intelligence. In the case of Raven, the difference between CG and GE (favorable to GC) dropped from d = .126 to .058. In the TNVRI test, the initial difference in favor of CG (d = .177) became negative (d = -.384), therefore in favor of GE. This small benefit was not observed in tests of school knowledge, where GC had the biggest gains in the post-test assessment. The results are partially supported in the literature. However, studies with a larger sample, more training sessions and longer interval between post-tests to verify the generality of these findings.(AU)

Evidências preliminares da efetividade do treinamento cognitivo para melhorar a inteligência de crianças escolares / Preliminary evidence of effectiveness in cognitive training to improve school children intelligence

Objetivou-se verificar a efetividade de um programa de treinamento cognitivo (TC) para melhorar a inteligência de crianças escolares. Participaram do TC 16 crianças (M = 8,75 anos; DP = 0,44) divididas em grupo controle (GC) e grupo experimental (GE), avaliadas no pré e no pós-teste com medidas de inteligência fluida, cristalizada e desempenho escolar. O TC consistiu da aplicação de tarefas de memória de trabalho por dois meses. Não foram encontradas diferenças significativas entre as medidas pré e pós-teste de inteligência. Entretanto, após o treinamento, observou-se redução das diferenças entre Gc e Gf em medidas de inteligência fluída. No caso do teste Raven, a diferença entre GC e GE (favorável a GC) caiu de um d = 0,126 para d = 0,058. No teste TNVRI a diferença inicial a favor de GC (d = 0, 177) passou a ser negativa (d = -0,384), portanto a favor de GE. Esse pequeno benefício não foi observado nos testes de conhecimento escolar, nos quais os maiores ganhos no pós-teste foram do GC. Os resultados encontram suporte parcial na literatura. Contudo, estudos com uma amostra maior, maior tempo de treinamento e de intervalo entre os pós-testes são necessários para verificar a generalidade de tais achados...

The present research intends to verify the effectiveness of a cognitive training (CT) to foster intelligence of school Brazilian children from different intellectual levels. Sixteen fourth-grade boys (M = 8.75 years; SD = .44) took part in this study and were randomly selected to the training group (TG) or control group (CG). In the pre and posttest, all children were assessed using measures with measures of fluid, crystallized intelligence, and school achievement. For the training program we used working memory task for a period of two months. Results: no statically significant difference was found between both groups at posttest in none of the measures used. However, after training, there was a reduction of the differences between GC and GF on measures of fluid intelligence. In the case of Raven, the difference between CG and GE (favorable to GC) dropped from d = .126 to .058. In the TNVRI test, the initial difference in favor of CG (d = .177) became negative (d = -.384), therefore in favor of GE. This small benefit was not observed in tests of school knowledge, where GC had the biggest gains in the post-test assessment. The results are partially supported in the literature. However, studies with a larger sample, more training sessions and longer interval between post-tests to verify the generality of these findings...

A influência aguda da prática mental sobre as oscilações corticais delta: um estudo piloto / The acute influence of mental practice on cortical delta oscillations: a pilot study

A prática mental (PM) é um método de treinamento pelo qual a representação interna de uma determinada ação motora é repetida diversas vezes com o objetivo de aumentar a performance motora. O objetivo deste estudo piloto foi avaliar a influência aguda da PM sobre as modificações da atividade cerebral utilizando a análise espectral do potencial relacionado a evento (PRE) e a magnitude quadrática da coerência (MSC) nas bandas de frequências delta, alfa e beta. Seis homens saudáveis (idade entre 20-25 anos) participaram deste estudo. Foram realizadas seis sessões individuais de PM baseada em imaginação motora (IM) de flexão e extensão da metacarpofalangeana do dedo indicador da mão dominante. Cada sessão consistiu de 15 minutos de IM, sendo realizada 2 vezes por semana, durante 3 semanas. Foram realizados registros de sinais de eletroencefalografia (EEG) antes e após as sessões de PM, durante: atividade espontânea; IM e; execução do movimento. Os eletrodos foram colocados nas derivações C3, C4 e Cz, de acordo com o sistema internacional 10-20. A potência do PRE e a MSC foram analisados para a derivação C3. Após o treinamento com a PM houve um aumento significativo (p = 0,03) na potência do PRE (normalizado com a potência da atividade espontânea) na banda delta durante a IM e o movimento do dedo. Além disso, houve aumento estatisticamente significativo da MSC durante a IM (F = 8,85, p = 0,001) e execução do movimento (F = 2,37; p = 0,048). Estes resultados sugerem a necessidade de se avaliar as mudanças na banda delta após a PM em novos estudos.

Mental Practice (MP) is a training method by which internal representation of a motor action is repeated several times to increase the individual's functional performance. This pilot study aimed to assess the acute influence of MI-based MP in oscillatory brain activity changes related to event related potential (ERP) power and magnitude square of coherence (MSC) at delta, alpha and beta frequencies. Six healthy volunteers (aged 20-25 years) participated in this study. One-on-one 15-minute MP training sessions were provided two days per week for three weeks. The MP sessions were performed based on motor imagery (MI) of the metacarpophalangeal flexion and extension of the dominant hand index finger. Electroencephalography signals were recorded before and after the training program, during spontaneous activity, MI and movement. Electrodes were positioned at C3, C4 and Cz locations, in accordance with the 10-20 international system. The ERP power and MSC were analized at C3 derivation. After MP, the ERP power (normalized with the spontaneous activity power) increased especially in delta band during the MI and execution (p = 0.03). After the MP period, MSC values increased for 5 subjects during MI (F = 8.85; p = 0.001) and movement execution (F = 2.37; p = 0.048), in that band. These results suggest the need to evaluate changes in delta band after the PM in new studies.

Effect of the rest interval duration between contractions on muscle fatigue.

BACKGROUND: We aimed to investigate the effect of rest interval, between successive contractions, on muscular fatigue. METHODS: Eighteen subjects performed elbow flexion and extension (30 repetitions) on an isokinetic dynamometer with 80º of range of motion. The flexion velocity was 120º/s, while for elbow extension we used 5 different velocities (30, 75, 120, 240, 360º/s), producing 5 different rest intervals (2.89, 1.28, 0.85, 0.57 and 0.54 s). RESULTS: We observed that when the rest interval was 2.89 s there was a reduction in fatigue. On the other hand, when the rest interval was 0.54 s the fatigue was increased. CONCLUSIONS: When the resting time was lower (0.54 s) the decline of work in the flexor muscle group was higher compared with different rest interval duration.