Maintenance and generalization of 40-Hz EEG biofeedback effects

Maintenance of conditioning of 40-Hz EEG activity was investigated in six adults 1 to 3 years after they had experienced biofeedback training to increase 40-Hz EEG. Subjects were first retrained to alternately increase and suppress 40-Hz EEG. All six subjects achieved a preset performance criterion in 16–20 minutes. Five of these subjects also subsequently demonstrated significant control of 40-Hz EEG without feedback. The sixth subject did not demonstrate control after 76 minutes and four sessions of attempted retraining with feedback. Transfer of 40-Hz EEG control to a problem-solving task was tested in all subjects in a final session. Cognitive test items were presented and subjects were instructed to alternately increase and suppress 40-Hz EEG while solving the problems. Rates of 40-Hz EEG in suppression periods during problem solving were significantly greater than during suppression periods without problems. No significant differences in problem-solving performance were found comparing 40-Hz increase and suppression periods. This study supports previous research suggesting an association between 40-Hz EEG and mental activity, and suggests methods for further study of transfer of EEG biofeedback effects.     

Effects of exposure to 30 kV/m, 60-Hz electric fields on the social behavior of baboons

We tested the hypothesis that exposure to a 30-kV/m, 60-Hz electric field produces significant change (stress) in the social behavior of adult male baboons (Papio cynocephalus anubis). One group of eight baboons was exposed to an electric field (12 hours per day, 7 days per week for 6 weeks) while a second group of eight baboons was maintained in a sham-exposure (control) condition. Exposed subjects and control subjects were compared over three, six-week experimental periods (pre-exposure, exposure, and post-exposure). Performance rates of six categories of social behaviors (passive affinity, active affinity, approach, tension, threat, and attack) and four categories of nonsocial behaviors (forage, manipulate, posture, and stereotypy) were used to compare the two groups. The results of our study indicate that 1) there were no significant differences between the two groups during the pre-exposure or post-exposure periods; 2) during the exposure period, experimental and control groups exhibited statistically significant differences in the mean performance rates of three behavior categories; 3) within-group comparisons across periods indicate that the experimentally exposed group exhibited statistically significant changes in passive affinity, tension, and stereotypy; and 4) changes in behavior performance among the exposed subjects reflect a stress response to the electric field.     

A double-blind investigation of the relationship between seizure activity and the sleep EEG following EEG biofeedback training

The sleep EEGs of eight medically refractory epileptic patients were examined as part of a double-blind, ABA crossover study designed to determine the effectiveness of EEG biofeedback for the control of seizures. The patients were initially reinforced for one of three EEG criteria recorded from electrodes placed over sensorimotor cortex: (a) suppression of 3- to 7-Hz activity, (b) enhancement of 12- to 15-Hz activity, or (c) simultaneous suppression of 3- to 7-Hz and enhancement of 11- to 19-Hz activity. Reinforcement contingencies were reversed during the second or B phase, and then reinstated in their original form during the final A′ phase. All-night polysomnographic recordings were obtained at the end of each conditioning phase and were subjected to both visual and computer-based power spectral analyses. Four of the patients showed changes in their nocturnal paroxysmal activity that were either partially or totally consistent with the ABA′ contingencies of the study. The spectral data proved difficult to interpret, though two trends emerged from the analyses. Decreases in nocturnal 4- to 7-Hz activity were correlated with decreases in seizure activity, and increases in 8- to 11-Hz activity were correlated with decreases in seizure activity. These findings were shown to strengthen the hypothesis that EEG biofeedback may produce changes in the sleep EEG that are related to seizure incidence.     

Operant conditioning of EEG rhythms and ritalin in the treatment of hyperkinesis

Enhanced voluntary motor inhibition regularly accompanies conditioned increases in the sensorimotor rhythm (SMR), a 12--14-Hz Rolandic EEG rhythm in cats.A similar rhythm, presumably SMR, has also been identified in the human EEG. The clinical effectiveness of SMR operant conditioning has been claimed for epilepsy, insomnia, and hyperkinesis concurrent with seizure disorders. The present report attempts to follow up and replicate preliminary findings that suggested the technique's successful application to hyperkinesis uncomplicated by a history of epilepsy. SMR was defined as 12--14-Hz EEG activity in the absence of high-voltage slow-wave activity between 4 and 7 Hz. Anticipated treatment effects were indexed by systematic behavioral assessments of undirected motor activity and short attention span in the classroom. EEG and behavioral indices were monitored in four hyperkinetic children under the following six conditions: (1) No Drug, (2) Drug Only, (3) Drug and SMR Training I, (4) Drug and SMR Reversal Training, (5) Drug and SMR Training II, (6) No Drug and SMR Training. All hyperkinetic subjects were maintained on a constant drug regimen throughout the phases employing chemotherapy. Contingent increases and decreases in SMR occurred in three of four training subjects and were associated with similar changes in classroom assessments of motor inactivity. Combining medication and SMR training resulted in substantial improvements that exceeded the effects of drugs alone and were sustained with SMR training after medication was withdrawn. In contrast, these physiological and behavioral changes were absent in one highly distractible subject who failed to acquire the SMR task. Finally, pretraining levels of SMR accurately reflected both the seve-ity of original motor deficits and the susceptibility of hyperkinetic subjects to both treatments. Although the procedure clearly reduced hyperkinetic behavior, a salient, specific therapeutic factor could not be identified due to the dual EEG contingency imposed combined with associated changes in EMG. Despite these and other qualifying factors, the findings suggested the prognostic and diagnostic value of the SMR in the disorder when overactivity rather than distractibility is the predominant behavioral deficit.     

Operant conditioning of EEG rhythms and ritalin in the treatment of hyperkinesis

Enhanced voluntary motor inhibition regularly accompanies conditioned increases in the sensorimotor rhythm (SMR), a 12–14-Hz Rolandic EEG rhythm in cats. A similar rhythm, presumably SMR, has also been identified in the human EEG. The clinical effectiveness of SMR operant conditioning has been claimed for epilepsy, insomnia, and hyperkinesis concurrent with seizure disorders. The present report attempts to follow up and replicate preliminary findings that suggested the technique's successful application to hyperkinesis uncomplicated by a history of epilepsy. SMR was defined as 12–14-Hz EEG activity in the absence of high-voltage slow-wave activity between 4 and 7 Hz. Anticipated treatment effects were indexed by systematic behavioral assessments of undirected motor activity and short attention span in the classroom. EEG and behavioral indices were monitored in four hyperkinetic children under the following six conditions: (1) No Drug, (2) Drug Only, (3) Drug and SMR Training I, (4) Drug and SMR Reversal Training, (5) Drug and SMR Training II, (6) No Drug and SMR Training. All hyperkinetic subjects were maintained on a constant drug regimen throughout the phases employing chemotherapy. Contingent increases and decreases in SMR occurred in three of four training subjects and were associated with similar changes in classroom assessments of motor inactivity. Combining medication and SMR training resulted in substantial improvements that exceeded the effects of drugs alone and were sustained with SMR training after medication was withdrawn. In contrast, these physiological and behavioral changes were absent in one highly distractible subject who failed to acquire the SMR task. Finally, pretraining levels of SMR accurately reflected both the severity of original motor deficits and the susceptibility of hyperkinetic subjects to both treatments. Although the procedure clearly reduced hyperkinetic behavior, a salient, specific therapeutic factor could not be identified due to the dual EEG contingency imposed combined with associated changes in EMG. Despite these and other qualifying factors, the findings suggested the prognostic and diagnostic value of the SMR in the disorder when overactivity rather than distractibility is the predominant behavioral deficit.     

Serum hormone concentrations during prolonged training in elite endurance-trained and strength-trained athletes

A study of 1 year was performed on nine elite endurance-trained athletes (swimmers) and on eight elite strength-trained athletes (weightlifters) in order to examine the effects of training on the endocrine responses and on physical performance capacity. The measurements for the determination of serum hormone concentrations were performed at about 4-month intervals during the course of the year. The primary findings demonstrated that during the first and most intensive training period of the year in preparing for the primary competitions similar but statistically insignificant changes were observed in the concentrations of serum testosterone, free testosterone and cortisol in both the endurance-trained and strength-trained groups. After that period the changes in hormonal response over the year were infrequent and minor. A significant (p less than 0.01) decrease occurred in the strength-trained group in serum-free testosterone during the second period, which was characterized by the highest overall amount of training. Over the entire year the concentrations of serum hormones remained statistically unaltered in both groups. Slight but statistically insignificant increases of 1.2% +/- 0.8% and 2.1% +/- 5.1% were observed in the competitive performances over the year in the endurance-trained and strength-trained groups, respectively. The present findings in the two groups of elite athletes, who differed greatly with regard to the type of physiological loading, demonstrated that the overall hormonal responses both during the most intensive and during prolonged training periods were rather similar and the infrequent small changes remained well within the normal physiological range.(ABSTRACT TRUNCATED AT 250 WORDS)     

Behavioral management of epileptic seizures following EEG biofeedback training of the sensorimotor rhythm

Eight severely epileptic patients, four males and four females, ranging in age from 10 to 29 years, were trained to increase 12–14 Hz EEG activity from the regions overlying the Rolandic area. This activity, the sensorimotor rhythm(SMR), has been hypothesized to be related to motor inhibitory processes(Sterman, 1974). The patients represented a crosssection of several different types of epilepsy, including grand mal, myoclonic, akinetic, focal, and psychomotor types. Three of them had varying degrees of mental retardation. SMR was detected by a combination of an analog filtering system and digital processing. Feedback, both auditory and/or visual, was provided whenever one-half second of 12–14-Hz activity was detected in the EEG. Patients were provided with additional feedback keyed by the output of a 4–7-Hz filter which indicated the presence of epileptiform spike activity, slow waves, or movement. Feedback for SMR was inhibited whenever slow-wave activity spikes or movement was also present. During the treatment period most of the patients showed varying degrees of improvement. Two of the patients who had been severely epileptic, having multiple seizures per week, have been seizure free for periods of up to 1 month. Other patients have developed the ability to block many of their seizures. Seizure intensity and duration have also decreased. Furthermore, the successful patients demonstrated an increase in the amount of SMR and an increase in amplitude of SMR during the training period. Spectral analyses for the EEGs were performed periodically. The effectiveness of SMR conditioning for the control of epileptic seizures is evaluated in terms of patient characteristics and type of seizures.     

Effect of sojourn at 4,300 m altitude on electroencephalogram and visual evoked response.

The purpose of the present study was to determine the effect of sojourn at high altitude on cerebral electrical activity. Electroencephalographic (EEG) and visual evoked responses (VER) were recorded from seven healthy males under the following conditions: 1) during the first 2-3 h at 4,300 m altitude when Pao2 was maintained at 90 mmHg (control condition), 2) during the first 2-3 h of hypoxia (Pao2 = 40 mmHg), and 3) at 24- to 48-h intervals during the first 9-12 days of hypoxia. Electrode placement was according to the 10-20 International Electrode System. The VER was recorded from an electrode at the inion referred to the left ear. We found no significant changes from control cerebral electrical activity during the first 2-3 h of hypoxia. One subject's VER amplitude was greater than control on the 2nd and 3rd days of hypoxia and a similar change from control was consistently evident in a second subject beginning the 5th day of hypoxia. These changes suggest cortical depression. After the 5th day changes occurred in the remaining subjects which would be consistent with cortical excitation. In three subjects, EEG frequency was increased, amplitude decreased, and/or spiking became evident. In four subjects VER amplitude was reduced. Our findings provide support for the hypothesis that certain behavioral and physiological changes induced by sojourn at altitude could be caused by alterations in central nervous system function.     

Gender differences in EEG coherent activity before and after training navigation skills in virtual environments

Gender differences in electroencephalographic activity (EEG) changes during navigation task performance after training were assessed in young adults. Female and male subjects were matched on initial navigation performance. EEG recordings were obtained while subjects navigated in an immersive virtual environment without visual cues, before and after a navigational skills training (9 sessions). In spite of task performance was similar in both groups, females showed higher theta band coherent activity between frontal and parietal and frontal and central regions than males before training. Correlation in theta band between fronto-central, fronto-parietal, and centro-parietal regions was enhanced in the left hemisphere for females but in the right hemisphere for males after training. Females also demonstrated a decreased in correlation in theta band over the right hemisphere between centro-parietal regions, whereas males demonstrated a similar effect over the left hemisphere. Navigation training seems to promote fronto-central-parietal synchronization in both genders but in different hemisphere. These results are interpreted as reflecting verbal-analytical working memory functions in females and global-spatial working memory mode in males.     

Cardiovascular response to interval and continuous training in women.

Three groups of five women (age = 18--25 years) participated in a 12-week training program. Cardiovascular responses up to 85% VO2 max to interval (ITG) and continuous (CTG) training were studied in two groups, before training and after 4, 8, and 12 weeks of training four times per week. A control group was assessed before and after 6 and 12 weeks. Both exercise groups demonstrated significant increases in Cao2--Cvo2 after 8 weeks with only slight further increases after 12 weeks (CTG = 8.9%, ITG = 20.0% at 85% VO2 max). No significant changes were noted in either group in SV (+ 5 ml ITG, + 9 ml CTG) or in their Qc. These results indicated that, in response to high intensity training, women may demonstrate similar cardiovascular adaptations to training as have been observed for men.     

Effects of biofeedback on the discrimination of electrodermal activity

Twenty-four subjects were tested on their ability to discriminate between the presence and absence of negative skin potential responses before and after training to control skin potential. Training consisted of 52 discrete 30-second trials during which subjects were asked either to increase or to inhibit palmar sweating. Subjects in groups N and P were provided with analogue feedback on their skin potential activity. Group N was correctly informed that increases in sweating were indicated by increases in the negativity of skin potential; group P was misinformed that these were indicated by increases in the positivity of skin potential. Subjects in the control (C) group received no feedback. Reliable evidence of discrimination was obtained only in groups N and P, following training. However, reliable evidence of control was obtained only in group N. Thus, training to control skin potential led to an ability to identify afferentation associated with the more common (i.e., negative) skin potential responses, even though biofeedback training appeared unsuccessful in the case of group P. These findings are discussed in the context of "discrimination" or "awareness" accounts of the process of acquiring control of internal response.     

Voluntary heart rate deceleration: A critical evaluation

This experiment was designed as a test of the view that the human heart rate (HR) deceleration response can be brought under voluntary control, when some form of exteroceptive feedback is available. Sixteen female volunteers were randomly assigned to two groups. The first group received instructions to decrease their HR plus a continuous negative (failure) binary feedback, while the second group received only the instructions. Each subject was given four sessions of HR deceleration training. Two identical tests were presented, one before and the other after the series of training sessions. These tests were divided into two parts. In the first part, subjects attempted to decrease their HR while undergoing an ischemic arm pain stress. In the second part, subjects performed a 40-trial HR discrimination task. The results indicate that all subjects decrease HR during both rest and voluntary control periods within each training session, but there are no significant group differences, no improvement in HR deceleration control over the four training sessions, and no difference in performance between rest and voluntary control periods. Similarly HR, blood pressure (BP), and the HR×BP product levels during the ischemic stress condition and the HR discrimination performance do not show group differences. It is suggested that the HR deceleration response may not meet the criteria generally applied to the definition of a voluntary response.     

EMG, muscle fibre and force production characteristics during a 1 year training period in elite weight-lifters

The effects of a 1 year training period on 13 elite weight-lifters were investigated by periodical tests of electromyographic, muscle fibre and force production characteristics. A statistically non-significant increase of 3.5% in maximal isometric strength of the leg extensors, from 4841 +/- 1104 to 5010 +/- 1012 N, occurred over the year. Individual changes in the high force portions of the force-velocity curve correlated (p less than 0.05-0.01) with changes in weight-lifting performance. Training months 5-8 were characterized by the lowest average training intensity (77.1 +/- 2.0%), and this resulted in a significant (p less than 0.05) decrease in maximal neural activation (IEMG) of the muscles, while the last four month period, with only a slightly higher average training intensity (79.1 +/- 3.0%), led to a significant (p less than 0.01) increase in maximum IEMG. Individual increases in training intensity between these two training periods correlated with individual increases both in muscular strength (p less than 0.05) and in the weight lifted in the clean & jerk (p less than 0.05). A non-significant increase of 3.9% in total mean muscle fibre area occurred over the year. The present findings demonstrate the limited potential for strength development in elite strength athletes, and suggest that the magnitudes and time courses of neural and hypertrophic adaptations in the neuromuscular system during their training may differ from those reported for previously untrained subjects. The findings additionally indicate the importance of training intensity for modifying training responses in elite strength athletes.     

The relations between filial and sexual imprinting in the domestic fowl: Effects of age and social experience

40 cockerels, were exposed to an artificial training model for 15 days. These sessions were between 1 and 15 days (‘I’ groups); 16 and 30 days (‘II’ groups); or 31 and 45 day (‘III’ groups) after hatching. Otherwise the subjects were reared either in isolation (groups Ii, IIi, IIIi) or in pars with a pullet (groups I♀, II♀, III♀). Sexual tests giving a choice between the training model and a novel model or a conspecific, were performed at maturity (5 months). Following responses during training suggested that all birds except group IIIi had established a strong filial attachment bond with their model. Results of tests on adults showed that the birds in group IIIi, with weak filial attachments to the training model, were however strongly sexually imprinted with the training model. The birds in groups Ii and IIi, with strong filial attachment to the training model, did not generally attempt to mate with the training model. All socially reared birds mated preferentially with the conspecific choice object but they also mated with the training model towards which they were all previously filially attached. It is argued that the development of a sexual preference is not a direct consequence of the filial attachment.     

Effects of exposure to a 60-kV/m, 60-Hz electric field on the social behavior of baboons.

We found in a previously reported study that exposure to a 30-kV/m, 60-Hz electric field had significant effects on the social behavior of baboons. However, it was not established whether or not the effects were related specifically to the 30-kV/m intensity of the field. A new experiment was conducted to determine whether or not exposure to a 60-Hz electric field at 60 kV/m would produce like changes in the baboons' social behavior. We exposed one group of eight male baboons to an electric field 12 hours a day, 7 days a week, for 6 weeks. A second group of eight animals was maintained under sham-exposure (control) conditions. Rates of performing on each of six categories of social behavior and on four categories of nonsocial behavior were used as criteria for comparing exposed with unexposed subjects and for within-group comparisons during three six-week experimental periods: Pre-Exposure, Exposure, and Post-Exposure. The results indicate that (1) during the exposure period, exposed animals exhibited statistically significant differences from controls in means of performance rates based on several behavioral categories; (2) across all three periods, within-group comparisons revealed that behaviors of exposed baboons were significantly affected by exposure to the electric field; (3) changes in performance levels probably reflect a stress response to the electric field; and (4) the means of response rates of animals exposed at 60 kV/m were higher, but not double, those of animals exposed at 30 kV/m. As in the 30-kV/m experiment, animals exposed at 60 kV/m exhibited significant differences in performances of Passive Affinity, Tension, and Stereotypy. Mean rates of performing these categories were 122% (Passive Affinity), 48% (Tension), and 40% (Stereotypy) higher in the exposed group than in the control group during exposure to the 60-kV/m field.     

The effect of whole-body vibration on jump height and active range of movement in female dancers

Whole-body vibration (WBV) has been shown to have beneficial effects on strength and power indices in sedentary and moderately trained individuals. The aim of this study was to investigate the effect of 4 weeks of WBV on jump height, active range of motion (AROM), and leg anthropometry in conservatoire dance students. Seventeen female dancers were randomly assigned to a control or intervention group. The intervention group trained for 30 seconds per position at a 35-Hz frequency, 8-mm displacement in the first 2 weeks, and 40 seconds at 40 Hz for the final 2 weeks, whereas the control group carried out the same exercises but without vibration stimulation. A significant (p < 0.01) difference in the intervention group was noted over time for vertical jump and active ROM. No significant changes over time were noted in the anthropometric data. In conclusion, WBV can be used as a beneficial supplemental training intervention to increase jump and active flexibility in highly trained dancers without corresponding increases in relative anthropometric data.     

Variable resistance versus constant resistance strength training in adult males

Changes in strength, body composition and anthropometric measures for groups training with constant resistance and variable resistance training procedures was compared. Thirty-six male volunteers were randomly assigned to one of three groups: Constant Resistance (CR), Variable Resistance (VR) and Control (C). Strength training was conducted 3 days per week, 45 min per day, for 10 weeks. The results demonstrated that both the CR and the VR groups increased muscular strength. The CR group demonstrated significant increases in strength over the VR group when strength was assessed by CR procedures. Conversely, the VR group demonstrated significant increases in strength over the CR group when strength was assessed by VR procedures. Neither group exhibited superiority over the other relative to changes in body composition and anthropometric measures. The significance of these results is discussed.     

Effects of two days of isokinetic training on strength and electromyographic amplitude in the agonist and antagonist muscles

The purpose of this study was to examine the effects of 2 days of isokinetic training of the forearm flexors and extensors on strength and electromyographic (EMG) amplitude for the agonist and antagonist muscles. Seventeen men (mean +/- SD age = 21.9 +/- 2.8 years) were randomly assigned to 1 of 2 groups: (a) a training group (TRN; n = 8), or (b) a control group (CTL; n = 9). The subjects in the TRN group were tested for maximal isometric and concentric isokinetic (randomly ordered velocities of 60, 180, and 300 degrees x s(-1)) torque of the dominant forearm flexors and extensors before (pretest) and after (posttest) 2 days of isokinetic strength training. Each training session involved 6 sets of 10 maximal concentric isokinetic muscle actions of the forearm flexors and extensors at a velocity of 180 degrees x s(-1). The subjects in the CTL group were also tested for strength but did not perform any training. Surface EMG signals were detected from the biceps brachii and triceps brachii muscles during the strength testing. The results indicated that there were no significant (p > 0.05) pre- to post-test changes in forearm flexion and extension torque or EMG amplitude for the agonist and antagonist muscles. Thus, unlike previous studies of the quadriceps femoris muscles, these findings for the forearm flexors and extensors suggested that 2 days of isokinetic training may not be sufficient to elicit significant increases in strength. These results may have implications for the number of visits that are required for rehabilitation after injury, surgery, or both.     

The impact of football training on motor development in male children

The aim of the study was to determine the effect of football school program and physical education curriculum on changes in the motor abilities of 7- and 8-year-old boys. The study included a sample of 180 boys divided into group 1 (7-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups, and group 2 (8-year-old boys), subdivided to experimental (n = 40) and control (n = 50) groups. Experimental groups included children attending three training units of football training over a 9-month period, in addition to the conventional physical education curriculum. Control groups included children attending only conventional physical education curriculum. All study subjects underwent testing with a battery of 12 motor tests at the beginning and at the end of the study. Results obtained by discriminative canonic analysis showed no statistically significant between-group difference in motor abilities at the beginning of the study. However, significant differences in favor of experimental groups were recorded at the end of the study. Favorable changes in all motor variables were observed in both experimental and control groups of children from the initial through the final state. These changes were more pronounced in experimental groups. Analysis of variance for difference variables (final to initial measurement) indicated programmed education in the form of football training in addition to regular physical education curriculum to predominantly influence the development of aerobic endurance, agility, speed and flexibility in 7-year-old boys, and of explosive strength, aerobic endurance, flexibility and speed in 8-year-old boys. In the latter, football training led to the formation of a motor complex integrating explosiveness, speed, coordination, endurance and flexibility as a general motor factor determining future quality development in football.