Biofeedback Control Mechanisms

 

   

 

 

 

 

 

 

 

 

Theoretical researches in the field of biofeedback have resulted in creation of the intellectual computerized complex "CARDIOTRAINING" (fig. 4), consisting of an ECG-converter, PC and the software.

fig.4

Fig. 4. The schema of the "CARDIOTRAINING" complex.

 

The basic idea of oscillatory cardiotraining is shown at the fig. 5.

fig.5

Fig. 5. An example of the combining (synchronization) of the own cardiorhythmogram (CRG) and sinus criterion function (CF). A young healthy man, test 33. RRmax - RRminim > 0.5 s (HRminim less than 45 b/min, HRmax is about 80 b/min).

The task of the subject is periodic (with the special rhythm of breath set by a sine curve as a criterion function) increase/downturn of his own heart rate at the continuous visual control. Cardiorespiratory synchronization lost as a result of some pathology recovers due to such kind of training. The biofeedback signal was displayed after processing on the monitor in real time as the CRG of the patient, describing the rate of the heart's beat. Simultaneously the sine-wave curve as a criterion or target function (CF) is presented on the screen. During training the patient has to try to bring two curves into coincidence - his own CRG and CF (fig. 5, 6). The researcher attracted patient's attention to interdependence of the CRG-variability and periodicity and amplitude of his breath.

fig.6

Fig. 6. The cardiorhythm scattergram.

Patients suffering with neurocirculatory distonia of hypertensive, hypotensive and normotensive types with cardial, astheno-neurotic, vasomotorial and respiratory syndrom took part in our examinations. They were not given any pharmacologic drugs during the cycle of cardiotraining. Every finished cycle consisted of 10 - 20 sessions with 8 tests (2 minutes) of BFBC; the session duration was about an hour. 
The cardiotraining procedure is used to estimate adaptive capabilities of the cardiorespiratory system, preliminary diagnostics of its state, training of cardiorhythm in the adaptive biotechnical system in the alternative oscillatory mode (up and down or inspiration/expiration correspondingly) for normalization of arterial blood pressure, heart rate, CRG and other parameters of the cardiorespiratory system. 
Oscillatory cardiotraining with an adaptive biological feedback fulfills the alternate training of regulation mechanisms of the cardiovascular and respiratory systems. It promotes obtaining of positive clinical results at the expense of expansion of the dynamic range of adaptive oscillatory processes. The BFBC through the dynamical changes of the breath pattern helps to reveal the patient's own frequencies and amplitudes of periodicity of the CRG fluctuations (fig. 7), which manifest themselves with the help of e CRG spectral analysis as own harmonics having higher amplitude - cardiorespiratory synchronization.

Fig.7a

Fig. 7. Cardiotraining dynamics in patient suffering with bronchial asthma.
Resp. - pneumogram (inspiration - ascending part of the curve) 

A - no cardiorespiratory synchronization in the 1-st test, 

 

Fig.7b

B - cardiorespiratory synchronization   (6 resp/min)

Fig.7c

C - cardiorespiratory synchronization (5 resp/min).

The effective BFBC produces the following changes in the CRG: formation of the own period of CRG-fluctuations at the initial absence of them; increase of the amplitude and period of the main CRG-harmonics. This is accompanied by improvement of the clinical state of the patients. The dynamics of some physiological parameters is shown at the fig. 8. Other measured and calculated parameters have analogous positive dynamics.

Fig.8

Fig. 8. Nonstationary dynamics of cardiovascular system parameters during the biofeedback control cycle consisted of 94 tests.

The patient suffering with neurocirculatory distonia of hypertensive type. 

There is a normalization of arterial blood pressure. 

The synchronization of the respiratory movements with the CRG- fluctuations promotes the amplification of synchronizing processes in slow bioelectrical activity of the brain (the normalization or recovery of alpha-rhythm in EEG), that activates integrative processes at the intersystem level of regulation and control. Positive clinical results are kept in 90% of patients for a year. 
So, the oscillatory adaptive biofeedback control of patient's own cardiorhythm makes practicable nonpharmacological correction of the human state caused by the syndromes mentioned above. This procedure helps to recover the sympathicovagal balance in the autonomic nervous system. The method can be used independently and in a combination with other therapeutics. It is patented also.