THE USE OF BRAIN BLOOD FLOW BIOFEEDBACK
IN OCCUPATIONAL MEDICINE

Vlad Tokarev, Ph.D.

INTRODUCTION

Rheoencephalography (REG) is a method widely used in Russia for continuous registration of brain blood flow. As a research procedure, REG has been used since the 60-70s, it has wide applications in clinics and hospitals in Russia as a tool for diagnosis of cerebrovascular disorders because of its simplicity of use and well-developed procedures for REG waveform recognition. As a rule, physicians in clinics make quantitative and qualitative estimations of the REG waveform for defining of cerebral vascular changes during stress or functional tests, particularly arteriosclerotic syndrome differentiation from various types of vessel tonus raising [1].

Recent research made by Kh.Yarullin, L.Sokolova [2,3] has shown that the REG waveform contains two well-recognized components: venous component and arterial one. Numerous scientific studies have shown that the amplitude and pattern of the REG waveform are correlated with changes in the brain blood vessels, i.e. arterial and venous components of blood system [3]. Low amplitudes of the arterial component and high amplitudes of the venous component suggest difficulties dealing with the cerebral blood flow. Patients having psychosomatic disorders (high arterial systolic blood pressure, headaches, arthritis, breaking of vestibule apparatus in the long working period of time), patients suffering from labile arterial hypertension, cardiovascular disease, neuro-circulatory distonia, neurotic and abstinent patient have high levels of the venous component of the REG waveform.

The ability of humans to change and control the arterial and venous components of the REG waveform during REG biofeedback and the positive results of the training in occupational medicine were investigated at the Applied Physiology laboratory, the Institute for Complex Problems of Hygiene and Occupational Diseases, Siberian Department of the Russian Academy of Medical Sciences, Novokuznetsk, Siberia, Russia.

SUBJECTS

Subjects were working operators of metallurgical rolling metal plants (West-Siberian Metallurgical Works), 82% of the total subject group, the other subjects were administrators, managers and metallurgical engineers (12%), they were a total of 241 subjects. The subjects had initial level of psychosomatic disorders with the symptoms of headaches, sleepiness, periodic blood pressure fluctuations. Clinical diagnosis based on Kulkovsky method were estimated by neuro-physiologists.

Subjects had 10 sessions over a two week period, each session was 40 min long. At the initial session, subjects meeting the following criteria were selected: 1) Maximum amplitude of the arterial component of the REG waveform has to be increased; 2) Maximum amplitude of the venous component of the REG waveform has to be decreased as soon as possible. Subjects were motivated to do the sessions because they were able to get medical service during the working day.

APPARATUS

The biofeedback training was performed using laboratory equipment for REG and EEG analysis and recording. Subjects were seated in a comfortable chair with adjustable back, head and arm supports. To measure REG, silver chloride electrodes of 15 mm were placed in the bi-frontal and bi-occipital positions of the head. The four-channel serial Russian rheograph 4GR-01 measures impedance variability and transforms it into ac voltage signal, which is amplified by AVK-31 analog computer complex (ACC). ACC divides the arterial and venous components of REG signal and shows it on 8-channel monitor for a subject. A threshold was manually controlled by a physician through the computation of arterial and venous component of the REG waveform. If the subject reaches the threshold, the sound and a green light support were available. A second physician's monitor duplicates the information for experimenter's purposes. A protocol structure of every session was taped on a recorder and replayed for each subject.

Each biofeedback session was processed and stored by ISKRA-226 personal computer, having standard interface and A/D converter for data acquisition [4]. Spectral and cross-spectral analysis of the REG waveform variability during biofeedback were obtained, and it was a subject of other publications [5,6]. In addition, a portable biofeedback training device was used for the subject's biofeedback training [7].

PROCEDURE

At the beginning of the session, the subject's REG was estimated for 3-4 min and the amplitudes of both arterial and venous components were saved as a baseline. During the sessions, a subject had 4-5 trials for 4.5 min period of REG biofeedback training and 3-4 periods of 2-3 min duration time-out. There were a total of 5 task periods, each followed by a time-out period. During the last task trial, the subject tried to reach the goal without any feedback.

Subjects were divided into three groups that differ by sex, age and occupation. Age range of each group was from 18 to 45. The subjects of each group had similar REG pattern and one clinical group's diagnosis. Group 1's task was to increase the arterial component of REG waveform, Group 2's task was to decrease the venous component of REG waveform, and Group 3's task was to both increase arterial component of REG and decrease venous one simultaneously, using different strategies of biofeedback training.

At the beginning and at the end of each session, the subject was estimated by psychological tests (I.Smekal and G.Kutcher and SAN [8]) to defined quantitative estimations of the emotional status, such as activity, mood (frame of mind), feelings, etc.; and blood pressure measurements.

The subjects were instructed to use different strategies, such as breathing, heat and fly feelings, music listening, imagination. The first and second sessions of the REG biofeedback training were supported by a physician who coached the subject and explain the details of the biofeedback.

RESULTS

The amplitude deviation of the REG waveform in normal conditions is about 2-4%. To define and quantify a success of the biofeedback training we established the criteria: if the subject reach the threshold (which is 10% of controlled amplitude) in the right direction, we suppose it as a success. Thus, all subjects were divided into 2 groups depending on a success.

The results of the REG biofeedback training are following: 195 subjects or 80.9% of total quantity had a success to control any component of REG waveform, and the correlation between REG pattern and new subject's functional status was significant at the level less then 0.5. Those subjects had a good emotional status calculated by SAN and Smekal/Kutcher psychological tests and labor productivity during the whole period of time after the biofeedback training. The labor productivity was estimated by managers supervising a worker during the work's shift. 85% of successful training group had no performance errors at the working place (usually they had from 0 to 4 errors a shift). This group of subjects had the successful learning results already in second or third sessions of biofeedback training.

The small group of 46 subjects or 19.1% has no positive results although they had some successful sessions. Their productivity and emotional status estimated by psychological tests had no changes after the biofeedback sessions. The hypothesis of a reason for the negative results is that the subjects in this group had low educational status (the group consists of workers only) and as a consequence, bad understanding of goals and tasks of the biofeedback training.

DISCUSSION

The results clearly indicated that humans are capable to control the brain blood flow, and there are able to recall the strategies for producing positive changes. The results also showed the potential for the use of REG biofeedback training in Occupational Medicine as a method to increase the worker’s ability to work with minimum quantity of errors as well as increase the labor productivity level. A control biofeedback session was repeated one month later and it showed that all subjects from the successful group can recall their strategies for the best results. The long-term labor productivity estimation after the biofeedback training is the subject of another investigation, and the results are not available in this publication.

REFERENCES

1. V.Tokarev, An REG Variability Estimation System Based On ISKRA 226.6 Personal Computer, Proceedings of the Scientific Conference, Novokuznetsk, 1989, p.115.

2. Kh.Yarullin, Clinical Rheoencephalography, Moscow, 1990, Medicine Publishing.

3. L. Sokolova (and others), Two-Component Analysis of REG Waveform, HUMAN PHYSIOLOGY, 1991.

4. V.Tokarev, Technical-Engineering Description of REG Biofeedback Training, Institute for Complex Problems of Hygiene and Occupational Diseases Reports, Novokuznetsk, 1988/1989, vol.23, pp.265-345.

5. V.Tokarev, Cross-Spectra As a Reflection Of Physiological Systems Interaction, Proceedings of the 10th International Congress on Medical Informatics, MIE'91, 1991, Vienna, Austria.

6. V.Tokarev, Evaluation of Regulatory Mechanisms of Physiological Systems During REG Biofeedback, Proceedings of the 25th Annual Meeting of AAPB, Atlanta, 1994, pp.168-171.

7. V.Tokarev, Russ. Pat. #4648078/14 - A Biofeedback Training Device, A61 B5/04 class.

8. Psychophysiological Tests, Moscow, NAUKA, 1979.

9. Alan T. Pope, Ph.D., Leslie D. Montgomery, Ph.D. ,Richard W. Montgomery, Ph.D. , Rheoencephalographic Analysis Discriminates Levels and Type of Mental Workload, NASA