Efficiency of biofeedback training of functional state regulation depending on individual psychophysiological characteristics

The psychophysiological characteristics of the subjects (emotional stability, autonomic lability, tension of autonomic regulation of cardiac activity, and EEG characteristics) were estimated. The efficiency of relaxation regulation training with the use of biofeedback (with the electrocutaneous impedance as a BF signal) was studied. Before and after BF training, an electrophysiological experiment was carried out, namely, a “relaxation test” without BF support. The test consisted of three situations: background, relaxation, and the state after coming out of relaxation. During the test, EEGs of different cortical areas (α bands) and autonomic indices were recorded. A short-term memory test was carried out with the purpose of controlling changes in the functional status. It has been shown that even a short training cycle of five sessions in most cases provided relaxation and improvement in self-regulation, accompanied by improvement of the mnestic activity. The effect of individual psychophysiological characteristics on the success of BF training has been established. A high autonomic lability, a high level of nonspecific cortex activity, as well as a dysfunction of the frontal-thalamic system, should be regarded as factors preventing effective self-regulation training.     

The effect of BFB training on the efficiency of voluntary relaxation in junior schoolchildren

Psychophysiological features of schoolchildren seven to eight and nine to ten years of age (their autonomic balance and brain functional state) were studied; the effect of biofeedback (BFB) training on the regulatory influence of relaxation was evaluated (BFB signal—electrical skin resistance). Before and after BFB training, the electrophysiological experiment, i.e., relaxation testing, was performed without BFB in three situations: background, relaxation, and the state after relaxation. The EEG of various cortical areas was recorded, and the electrical skin resistance was determined. The short-term memory test was used to determine changes in the functional state at the behavioral level. Short-term training (five sessions) often enhanced the efficiency of voluntary relaxation and improved the postrelaxation mnestic function only in the group of 9- to 10-year-old children. The effect of training on the relaxation of the regulation depended on the individual psychophysiological features of children.     

The functional state of the sympathoadrenal system and the autonomic regulation of the cardiac rhythm in younger schoolchildren

A comparative analysis of functional states of the sympathoadrenal system (SAS) and its reactions to isometric muscular effort was performed in seven-year-old schoolchildren of both sexes with different types of cardiac regulation. Children with a predominance of sympathetic influences displayed a higher excretion of noradrenaline and a lower excretion of dopamine than their counterparts with normal or vagal tone. A graded isometric exercise changed the functional state of the SAS in a manner dependent on the initial autonomic tone, baseline excretion of catecholamines, and sex. Boys displayed more strained reactions of the SAS than girls did, which was associated with a decrease in its reserve potential, especially pronounced in the states of vagal and normal tones. This suggests imperfect mechanisms of adaptation to static loads.     

Effects of voluntary control of the functional state on the organization of cortical processes during mnemenic activity in schoolchildren aged nine to ten years

In schoolchildren aged nine to ten years, the analysis of EEG indices (spectral power density, the function of coherence in the α band) of different cortex regions in four experimental situations—quiet wakefulness, mnemenic activity, relaxation, and mnemenic activity in the postrelaxation period—was performed. In the mnemenic activity situations, a task for determining the short-term auditory-speech memory span was used. A positive effect of relaxation on the efficiency of mnemenic activity expressed in an increase in the short-term memory span was found. Comparison of groups formed according to the increase in the memory span showed differences in the dynamics of coherence indices. Only in children with a pronounced postrelaxation increase in the memory span in the situation of mnemenic activity was an increase in coherence in the high-frequency subrange of the α band of the EEG detected, whose functional significance is related to selective inhibition.     

The functional state of microcirculation and autonomic regulation in young subjects with different levels of subjectively experienced psychological stress

A comprehensive comparative analysis of hemodynamics, microcirculation (the method of laser Doppler flowmetry with an occlusion test and the optical tissue oxymetry), blood circulation neurohumoral regulation (analysis of heart rate variability, HRV) in apparently healthy young subjects with different levels of subjectively experienced emotional stress has been performed. Depending on the degree of everyday stress (acute and/or chronic), the character of the autonomic regulation of blood circulation, as well as the state of the microcirculation and its regulation substantially vary. Moderate stress is accompanied by coactivation of sympathetic-parasympathetic regulatory mechanisms with augmented HRV baroreflex regulation circuits, which compensates for hemodynamic changes and is not accompanied by hypotensive reactions. An increase in the activity of neurogenic and myogenic tones of microhemodynamics in the subjects with moderate stress, which determines a high probability of blood shunting in tested tissue and decrease in relative oxygen extraction, has been discovered. Moderate levels of stress are also associated with an increase in the latency of postocclusive vasoreactive hyperemia, which is considered to be an early sign of the endothelium-mediated dysfunction of microcirculation.     

The influence of training status on oxidative stress in young male handball players

Molecular and Cellular Biochemistry - Although exercise-induced oxidative stress receives considerable scientific attention, there is still little information available regarding exercise-induced...     

Voluntary regulation of the functional state and its influence on the effectiveness of cognitive activity during adolescence

We have analyzed the impact of voluntary relaxation on the functional organization and the effectiveness of the voluntary prestimulus attention in performing cognitive tasks in adolescents at the ages of 12–13 and 13–14 years. The effectiveness of cognitive task performance (audio-verbal short-term memory) was estimated on the basis of the number of correctly remembered words. We have found that both age groups are characterized by reduced capacity for voluntary relaxation and its impact on the effectiveness of cognitive task performance. The analysis of the coherence function of EEG rhythmic components in a situation of voluntary attention focused on the performance of cognitive tasks showed no significant change in the interaction of the prefrontal cortex with other cortical areas during the switch from quiet wakefulness or post-relaxation state to the preparation to perform the task, which is typical of adults and young children. Our findings can be a result of sub-optimal functioning of voluntary regulation mechanisms and organization of activities during adolescence.     

The voluntary regulation of consciousness levels

A capability for voluntary regulation of the intensity of spontaneous mental verbal associations (without external feedback) was found in several persons from 28 examined subjects. Due to this capability, these persons could control the level of consciousness and voluntary produce the corresponding EEG changes from the EEG enhancement to substantial decrease in its power (to appearance of the flattened EEG).     

Typoloagical characteristics of the functional state of regulatory systems in schoolchildren and young athletes (According to Heart Rate Variability Data)

This article is based on the heart rate variability data obtained during a 15-year study of schoolchildren and athletes from 7 to 18 years old. The typological characteristics of the functional state and the adaptive capacity of regulatory systems were determined. It is shown that the functional state, reactivity, and adaptive capacity of regulatory systems depend primarily on the regulation type rather than on age. It is established that different mechanisms of heart rate control are switched in children and athletes with different regulation types during the performance of the same test and physical loads.     

Functional maturation of the brain and formation of the neurophysiological mechanisms of selective voluntary attention in young schoolchildren

A particular role was demonstrated for functional maturation of the frontothalamic system (FTS) of the brain in forming the cerebral organization of selective voluntary attention in ontogeny. Analysis of the coherence of the rhythmic components of the EEG α range in adults and seven-to eight-and nine-to ten-year-old children showed that, if the functional state of the control structures corresponds to the age, the formation of the neurophysiological mechanisms selectively modulating cortical activity and supporting selective tuning of the cerebral structures to the cognitive task is completed by the age of seven or eight years. Unlike adults, children demonstrated no interhemispheric features of the intercenter integration of cortical zones in the prestimulus period of voluntary attention. Children with a functionally immature FTS lacked selective specific integration of cortical zones in the pretuning period. The deficit of selective modulation of cortical activity in children with a functionally immature FTS is considered as the neurophysiological factor that delays the formation of voluntary attention and voluntary control of activity and, finally, leads to learning difficulties.     

The effectiveness of EMG biofeedback training in low back pain

Eighteen patients with chronic low back pain(lbp) of muscle tension origin were given an EMG biofeedback training. Compared to seven controls they showed a significant decrease during training in muscle tension and subsequently in pain. However, at follow-up EMG levels dropped to the initial(high) level. Pain scores of patients with high pain decrements during training showed further improvement during follow-up, which was not the case with patients showing less substantial improvement. The importance of cognitions was discussed.We wish to express our thanks to Marijke Höweler-van Dalen for supervising this investigation, to Arnold Goedhart for statistical advice, to Dr. Orlebeke for his critical remarks, and to Dr. Penders for referring the patients in Amsterdam. We are particularly indebted to the general practitioners Paul Kreutzer and Jan Huls for referring the Andijk patients. Without their support this investigation would not have been possible.     

Effect of voluntary activation on age-related muscle fatigue resistance

Ageing is associated with a higher fatigue resistance during submaximal or maximal fatiguing contractions. The present study aimed to investigate the contribution of the central and peripheral fatigue to the age-related differences in fatigue development of the plantar flexor muscles. Therefore, the voluntary activation, rest twitch moment and voluntary plantar flexor moment were examined before during as well as 2, 5 and 10min after a fatiguing task. This consisted of intermittent isometric submaximal plantar flexor contractions at equal intensity for both young and old adults (considering the age-related differences in muscle inhibition). Consequently, possible differences between young and old adults in voluntary activation during the maximal contraction utilised for determining the intensity of the fatiguing task, which can influence fatigue development, have been taken into account. The plantar flexors moment was calculated using inverse dynamics and the voluntary activation was measured using the twitch interpolation technique. Changes in voluntary activation and rest twitch moment during the fatiguing task were used to assess central and peripheral fatigue, respectively. In both young and old adults, peripheral ( approximately 20%) as well as central fatigue ( approximately 9%) contributed to the time to task failure. Old adults demonstrated greater time to task failure than young ones, but similar voluntary activation behaviour during the fatiguing task. We concluded that, the age-related enhancement in fatigue resistance is not attributable to voluntary activation but is linked to mechanisms located within the working muscle.