Benoît Bolmont

The time course of autonomic parameters and muscle tension during recovery following a moderate cognitive stressor: Dependency on trait anxiety level

It has proved difficult to demonstrate the differences in physiological response in individuals with contrasting trait anxiety levels. The purpose of this study was to examine tonic autonomic activity and muscle tension in male subjects with different levels of trait anxiety during and especially after a stressful situation. Twenty-eight low anxiety (LA) and thirty-one high anxiety (HA) individuals performed a video-recorded Stroop color-word interference test. Heart rate, skin conductance level, finger temperature, electromyographic activity of gastrocnemius and trapezius muscles were recorded; state anxiety and valence of thought content were assessed. Physiological activity increased during the stressful situation, whatever the group. However, prolonged gastrocnemius muscle tension and prolonged decrease in finger temperature were found in HA subjects after the stressful situation, but not in LA subjects. These results suggest that physiological recovery following a moderate cognitive stressor could depend on trait anxiety level.

The trapezius muscle uniquely lacks adaptive process in response to a repeated moderate cognitive stressor

The aim of this study was to examine the adaptive process of muscular responses in healthy subjects over two repeated exposures to the same moderate cognitive stressor. The electromyographic (EMG) activity of the flexor pollicis brevis, biceps brachii, triceps brachii, trapezius, gastrocnemius and soleus muscles was recorded in 35 males during video-recorded Stroop color-word interference tests. The results showed lower EMG activity in all muscles during the second exposure to the stressful task, but not in the trapezius muscle. These findings could help to the understanding of the role of stressful situations in the development of musculoskeletal disorders.

Impact of anxiety on verbal and visuospatial working memory in patients with acute stroke without severe cognitive impairment

Background Working memory is the most impaired cognitive domain in the acute phase of stroke. In a context where anxiety is highly prevalent, close attention must be paid to anxiety which could mimic mild to moderate working memory impairments. This is the first study to assess the contribution of state anxiety (the currently experienced level of anxiety) to the working memory (verbal, visuospatial) in patients with first-ever acute stroke without severe cognitive impairment. Methods 28 patients with first-ever acute stroke and 41 matched control subjects were exposed to a neutral condition and an anxiogenic condition in which verbal (VWM) and visuospatial working memory (VSWM) performance and state anxiety were assessed. State anxiety was assessed before the beginning of the experiment (baseline), after the neutral condition and after the anxiogenic condition. Results The mean state anxiety score was higher in patients than in controls in the neutral (z=1.9, p<0.05) and anxiogenic (z=2, p<0.05) conditions despite a similar level at baseline. Multiple regression analyses with a dummy variable ‘group’ (patients vs controls) showed that increased state anxiety in patients contributed significantly more to both reduced VWM (β=−0.93, p<0.05) and VSWM (β=−1, p<0.05) performance between the neutral and anxiogenic conditions compared to controls. Conclusions In a stressful context, the contribution of state anxiety to reduced working memory performance is more pronounced in patients with acute stroke than in controls. These results are of particular relevance for clinicians assessing patients in the acute phase of stroke in which anxiety is highly prevalent.

Personality traits of people attracted by parabolic flight.

BACKGROUND Studies have shown that members of expeditions in extreme environments differed on the basis of personality factors (e.g., they were highly competitive, higher on Extraversion and Conscientiousness) compared to the control population. In order to identify individuals who are likely to participate in extreme environments, the aim of the present study using parabolic flights was to compare the personality traits of voluntary participants (VP) in a weightlessness experiment with those of the general population (GP) (French norms). METHODS The personalities of 57 voluntary participants in a parabolic flights experiment were assessed using NEO-PI-R and Trait-Anxiety. RESULTS Our results show significant differences with the general population: (1) in Trait-Anxiety (GP = 42.25 +/- 11.44 vs. VP = 34.56 +/- 6.24) and in 3 out of 5 personality domains (Neuroticism GP = 90.04 +/- 22.68 vs. VP = 78.70 +/- 17.44, +/- 18.87 vs. VP = 123.81 +/- 15.41, and Conscientiousness GP = 109.23 +/- 22.30 vs. VP = 124.47 + 19.03); and (2) in 14 out of 30 NEO-PI-R facets. DISCUSSION These findings indicate a specific personality profile for voluntary participants in parabolic flights and confirm that participants attracted to extreme environments differ compared to the normative population.

Paradoxical State Anxiety and Working Memory in a Patient with Acute Stroke

Objective:In view of the negative impact of anxiety on working memory, we induced anxiety in 26 patients with acute stroke and 33 healthy controls, and studied how the anxiety affected their emotional reactivity and how the reactivity affected their verbal and visuospatial working memory. We compared the overall findings with those in 1 of our patients (C.B.) who had presented with an abnormally high level of state anxiety. Methods:We gave verbal and visuospatial 1-back tasks under both neutral and anxiogenic conditions, and we compared participants’ working memory scores, self-reported levels of state anxiety, and electrodermal activity. Results:When comparing performance in the neutral condition, the control and patient groups exhibited disrupted verbal working memory, which was associated with greater electrodermal activity and higher state anxiety during the anxiogenic condition. Although patient C.B. also had heightened electrodermal activity during the anxiogenic condition, she experienced a significant reduction in her state anxiety. Her verbal working memory was better during the anxiogenic than the neutral condition. Conclusions:Because of the phonological (subvocal speech) nature of verbal working memory, a higher level of anxious apprehension could explain the increase in state anxiety and the corresponding disruption of verbal working memory in our patient and control groups during the anxiogenic condition. C.B.’s lower state anxiety and selective improvement in verbal working memory during the anxiogenic condition suggest that she felt less anxious apprehension.

Vibrotactile Pattern Recognition: A Portable Compact Tactile Matrix

Compact tactile matrix (CTM) is a vibrotactile device composed of a seven-by-seven array of electromechanical vibrators “tactip” used to represent tactile patterns applied to a small skin area. The CTM uses a dynamic feature to generate spatiotemporal tactile patterns. The design requirements focus particularly on maximizing the transmission of the vibration from one tactip to the others as well as to the skin over a square area of 16 cm2 while simultaneously minimizing the transmission of vibrations throughout the overall structure of the CTM. Experiments were conducted on 22 unpracticed subjects to evaluate how the CTM could be used to develop a tactile semantics for communication of instructions in order to test the ability of the subjects to identify: (1) directional prescriptors for gesture guidance and (2) instructional commands for operational task requirements in a military context. The results indicate that, after familiarization, recognition accuracies in the tactile patterns were remarkably precise for more 80% of the subjects.

Reaction time and physiological signals for stress recognition

Abstract This paper investigates the potential of stress recognition using the data from heterogeneous sources. Not only physiological signals but also reaction time (RT) is used to recognize different stress states. To acquire the data related to the stress of an individual, we design the experiments with two different stressors: visual stressor (Stroop test) and auditory stressor. During the experiments, the subjects perform RT task. Three physiological signals, Electrodermal activity (EDA), Electrocardiography (ECG) and Electromyography (EMG) as well as RTs are recorded. We develop the classifier based on the Support Vector Machines (SVM) for the stress recognition given the physiological signals and RT respectively. An overall good recognition performance of the SVM classifier is obtained. Besides, we present the strategy of recognition using the decision fusion. The recognition is thus achieved by fusing the classification results of physiological signals and RT with the voting method and a further improvement of recognition accuracy is observed. Results indicate that RT is efficient for stress recognition and the fusion of physiological signals and RT can bring in a more satisfied recognition performance.

Sensation Seeking and Adaptation in Parabonauts

Evidence from extreme environments suggests that there are relationships between difficulties of adaptation and psychological factors such as personality. In the framework of microgravity research on humans, the aim of this exploratory study was to investigate inter-individual differences of parabonauts on the basis of quality of adaptation to the physical demands of parabolic flights. The personality characteristics of two groups of parabonauts with a different quality of adaptation (an Adaptive group, N = 7, and a Maladaptive group, N = 15) were assessed using the Sensation Seeking Scale, Brief COPE, and MSSQ-Short. Compared to the Maladaptive group, the individuals of the Adaptive group scored higher on Boredom Susceptibility (i.e., a subscale of the Sensation Seeking Scale), lower on scales of susceptibility to motion sickness (MSSQ-Short) and tended to score lower on Instrumental Support Seeking (i.e., a subscale of the Brief COPE). These results suggest that individuals of the Adaptive group are more intolerant to monotony, present an aversion to repetitive and routine activities, are less susceptible to motion sickness and less dependent on problem-focused strategies. These characteristics may have contributed to developing a certain degree of flexibility in these subjects when faced with the parabolic flight situation and thus, may have favored them. The identification of differences of personality characteristics between individuals who have expressed difficulties of adaptation from those who have adapted successfully could help to prevent the risk of maladaptation and improve the well-being of (future) commercial or occupational aerospace passengers. More generally, these results could be extended to extreme environments and professional and/or sports domains likely to involve risk taking and unusual situations.

Dedicated wavelet QRS complex detection for FPGA implementation

The QRS complex is the most significant segment in the Electrocardiography (ECG) signal. By detecting its position, we can learn the physiological informations of the subjects, e.g. heart rate. In this paper, we propose a FPGA architecture for QRS complex detection. The detection algorithm is based on Integer Haar Transform (IHT). Due to its integer nature, the IHT avoids the floating point calculations and thus can be easily implemented in FPGA. The FPGA Cyclone EP3C5F256C6 is used as the target chip and all the components of the system are implemented in VHSIC Hardware Description Language (VHDL). The testing results show that the proposed FPGA architecture can achieve an efficient detection performance where the total detection accuracy exceeds 98%. Meanwhile, the FPGA implementation shows good design efficiency in the term of silicon consumption. Only 8% silicon resources of the target chip are occupied. The proposed architecture will be adopted as a core unit to make a FPGA system for stress recognition given the heterogeneous data.

Moderate anxiety modifies the electromyographic activity of a forearm muscle during a time-reaction task in women

Arousal anxiety has a great impact on reaction time, physiological parameters and motor performance. Numerous studies have focused on the influence of anxiety on muscular activity during simple non ecologic task. We investigate the impact of a moderate state-anxiety (arousal stressor) on the specific component of a complex multi-joint ecologic movement during a reaction time task of auditory stimulus-response. Our objective is to know if central and peripheral voluntary motor processes were modulated in the same way by an arousal stressor. Eighteen women volunteers performed simple reaction time tasks of auditory stimulus-response. Video-recorded Stroop test with interferences was used to induced moderate state-anxiety. Electromyographic activity of the wrist extensor was recorded in order to analyse the two components of the reaction time: the premotor and motor time. In anxiogenic condition, an acceleration and an increase of muscular activity of the reaction time was obtained. This increase was due to a stronger muscle activity during the premotor time in the anxiogenic condition. Arousal anxiety has a different impact on central and peripheral voluntary motor processes. The modifications observed could be related to an increase in arousal related to a higher anxiety in order to prepare the body to act.