G. Delhomme

Bioelectric and microcirculation cutaneous sensors for the study of vigilance and emotional response during tasks and tests

Bioelectronic phenomena related to the activity of the Autonomic Nervous System (ANS) activity mainly take place in the deep part of the brain where they are difficult to record. The hand skin, being richly innervated by sympathetic efferent fibres, offers an interface from which relevant ANS-related signals can be recorded. Two non-invasive bioelectronic measurements (skin resistance and potential) reflecting the activity of the ANS were performed at the skin surface. These measurements were complemented by thermovascular (skin microcirculation and skin temperature) and cardiorespiratory (instantaneous heart rate and instantaneous respiratory frequency) measurements. The bioelectric measurements were performed using noninvasive Ag/AgCl electrodes. Non-metallic NASICON (Na Super Ionic Conductor) electrodes were tested and compared with traditional electrodes for the optimization of bioelectric measurements. Signal analysis and data processing was accomplished by means of original indices on a specially designed PC-based software. The methodology was used to evaluate vigilance level, mental workload, and emotional response during tasks (sporting activity, mental calculation, olfactive stimuli) and in critical situations (car crash avoidance).

Increased activation as a limiting factor of performance in sharp shooters

The measurement of autonomic nervous system (ANS) activity was performed on 10 male and five female sharp shooters (rifle) during competitions. Electrodermal, thermovascular, cardiorespiratory variables and two indices of performance were recorded simultaneously. When the subjects fired shots that hit the target, they had a higher number of negative skin potential responses than when they missed. The responses had lower amplitude but lasted longer than when the shots missed the target. Good performance seemed to depend on high levels of motivation (increase in negative potential response), better mastery of the emotional reactivity (low amplitude response), and greater concentration time (increased duration of response).

A model of sporting performance constructed from autonomic nervous system responses

SummaryFour autonomic nervous system (ANS) variables: skin potential and resistance, skin blood flow and temperature — plus instantaneous heart rate and respiratory frequency — were simultaneously recorded during sporting competitions. The performances of 15 marksmen and 7 archers were analysed by comparing the variations in the six parameters during a concentration phase prior to shooting and during the shooting (or active) phase proper. The results of the performances distinguished two groups of sportsmen: firstly, the best shots and secondly, the worst shots. Comparison of the autonomic responses between the groups showed statistically significant correlations among the ANS variables. This made possible a relationship between performance characteristics and a percepto-effector factor to be defined. More precisely, this factor was defined as the number of correlations of the measured variables in the two phases, concentration and shooting. A positive relationship was demonstrated —the higher the factor, the better the performance. In addition, the stability of the factor, was greater within the best marksmen and archers groups. A model of the temporal change of the percepto-effector factor in both groups was given in three dimensions. This modelling of performance characteristics gave a visual indication of the differences between best/worst performances.