Biofeedback monitoring-devices for astronauts in space environment

Acta Astronautica Vol. 10, No. 8, pp. 591-598, 1983

0094-5765183 $3.00+ .00 Pergamon Press Ltd.

Printed in Great Britain.

Academy Transactions Note BIOFEEDBACK MONITORING-DEVICES FOR ASTRONAUTS IN SPACE ENVIRONMENTt G. ROTONDO,:~P. PANCHERI,F. MONESI,G. GRANTALIANOand V. DEPASCALIS U n i v e r s i t y of R o m e , Via C o n c a d ' O r o 348 00141 R o m e , Italy

(Received 2 November 1982)

Abstract--After a reconsiderationof the state-of-the-artin biofeedbackresearch the implementationof biofeedback systems is envisioned as a countermeasure of stress for the psychoprophylaxisof the astronaut. A one-session experimentperformedon two groupsof subjects to assess the interferencefrom EMG-feedbackon the performancein a simultaneouspsychomotortrial with a viewto expandingbiofeedbackapplicationis described.The results show that the experimentalgroupperformedin the sameway as the controlwithoutfeedback,but withless CNS activation.Some general conclusionsare drawn from the advances in technology.

regulate and decrease their psychophysiological arousal level in both basal and emergency situations thus enhancing their performance [16, 17]. Hence biofeedback appears to be a technique which may improve the psychophysiological prophylaxis of the astronaut. Its utilization in space flight can be considered and investigated at various application levels. A case in point is the introduction of one or more breaks in the daily routine of the astronaut who attempts to become as relaxed as possible by monitoring a physiologic function. A further application level of such capabilities of quick voluntary control of somatic functions regulated by the autonomic system as heart rate, blood pressure, breathing rate, muscle tonus, skin temperature might be recommended as a biofeedback training program which, once taught and learned, prior to space missions, could actually be practised by astronauts as an additional safety measure providing them with information about their physiologic functions electronically detected, amplified and fed back from a monitoring device. However, biofeedback application along with task implementation requiring attention raises the problem of possible interferences in overall performance. Studies on the effects of thermal biofeedback during problem solving revealed that the subjects were able to control finger temperature with no decrease in performance [28]. The same conclusion was drawn from an investigation on EMG feedback also during problem solving[10, 21]. Since the astronaut personality is a particular example of unique stressors and adaptive requirements, reaction to stress and its control are the central paradigm for looking at his mental health. Aim of the research. Assessment whether EMG feedback may be utilized simultaneously with learning and implementation of psychomotor trials without bringing about, as shown by some variables, both physiologic as EMG, ECG, EEG and psychometric as state anxiety according to Spielberger, interferes in task performance.

l. INTRODUCTION

Because of its intrinsic features (weightlessness) as well as demanding operational conditions (confinement, unprecedented maneuvers) space environment is likely to induce some physiological modifications conceptualized as a reaction to stress by Selye[19]. It has long been recognized that stress induced changes at neurophysiological, psychoendocrine level interfere with psychophysical performance causing its disruption when somatic activation goes beyond a limit characteristic of everybody[13, 15, 24]. In the ultimate conditions typical of space environment stress induced reactions must be quickly mastered before they spin out of control. This goal is usually attained through the selection and preliminary training; however optimum stress control capability is the limit one can approach but not achieve by usual methods. When biofeedback technique has been applied to humans, it has been shown that everybody, if properly trained, can reach a quite high level of voluntary control of the somatic functions regulated by the autonomic nervous system [2, 8, 14, 18]. Heart rate [3, 22, 26], blood pressure[9, 20, 23, 25], skin temperature[4, 7, 12] and muscle tonus[1, 5, 27] are some among the variables for which quick voluntary control is likely to occur after biofeedback training. The emotional factors associated with the implementation of complex tasks in space work call thereafter for the introduction of ways and means to enhance performance toward a more specific utilization of psychophysiological activation and a limitation of overall vegetative arousal with no impairment of higher mental functioning[6, 11]. Studies performed at the 5th Psychiatric Clinic of Rome University showed that there are subjects who learn how to tPaper presented at the 33rd Congress of the International AstronauticalFederation, Paris, France, 27 September-2October 1982. ~:AcademyCorrespondingMember (Section 3). 591

G. ROTONDOet al.

592 2. MATERIALAND METHODS

2. I Subjects Twelve airmen selected at random among the flying personnel of the Italian Air Force in similar conditions as to skill, health and age (30--40yr) served as subjects. 2.2 Equipment The subjects entered an electrically isolated, soundattenuated and dimly lighted room after a short briefing. Thorough tape-recorded information was provided stepwise after having them comfortably heated and connected to the devices for recording bioelectrical signals, EEC activity was recorded by bipolar leads through silver chloride disc electrodes from temporoparietal--left (T3-P3) and right (T4-P4)--regions with one reference electrode located on the vertex (CZ), amplified by Mingograf EEG l0 and fed into an analogic tape recorder RACAL. ECG was recorded by the same devices with a reference electrode located on the earlobe. Frontalis muscle tension EMG was recorded with Autogen 1700 with a bandwidth of 100-1000 Hz. The same device provided a feedback tone proportional to muscle tension level, EMG tension levels being averaged every minute. Bioelectrical signal analysis was performed by a HP 1000 computer based software program designed to provide Fast Fourier Transform spectral analysis in theta (3-8.5), alpha (8.5-12) and beta (12-32 Hz) EEG bands. 2.3 Procedure Twelve subjects were allotted at random to two groups, each of six experimental and control individuals. They first filled out a Spielberger's STAI-X1 questionnaire and then underwent a unique session broken down into ten subsequent trial periods, viz. subsessions. A thorough tape recorded message was given to everybody prior to every trial period. Subjects serving on the control group were provided with no instructions about Bfb, but invited to attempt to become as relaxed as possible. During the session the subject was involved three times in a psychomotor trial test representing a chase-and-flight game displayed and scored on a video terminal by an electronically driven machine. The way scores were assigned to the games was inversely proportional to performance. Errors were first recorded every minute and then the mean percentage value was calculated for each of the three trial periods. Each experimental session consisted of the following subsessions: 3rain of baseline, eyes closed; 7rain of baseline, eyes open; 5 rain of psychomotor trial game learning; 3 rain of adaptation; 5 min of EMG-feedback; 10rain of psychomotor trial performance along with EMG-feedback; 3rain of adaptation; 5rain of psychomotor trial performance along with EMG-feedback; 3 rain of adaptation. In the control group the subjects underwent the same trial periods, but instead of Bib they received the instruction to become as relaxed as possible. In all the situations the subjects kept their eyes open but for the first baseline periods when eyes were closed. Both groups heard a variable frequency tone through the earphones with the difference that in the control group it

was never valued as a signal. In the experimental group the tone was not representative of muscle tension in those periods when no Bfb was scheduled, and the subject was kept apprised of it. Both sessions terminated with a second administration of Spielberger's STAI-XI questionnaire.

3. RESULTS

3.1 Analysis of EMG data Within both groups baseline EMG levels did not show any significant difference. Thereupon, each subsession was compared by Student's t test. The experimental group showed significantly lower EMG levels in: (game + Bfbh vs (game+relaxation),; (Bfb)2 vs (relaxation)2; (game + Bfb)2 vs (game + relaxation)2 (Table 4). Within both groups at the comparison with baseline periods (eyes open) by Student's t for matched pairs the [following significant differences were observed: (a) experimental group: increase in EMG values during game learning (t = 4.62; d[ = 5; p < 0.01); decrease during Bfb2 (t =4.10; dr= 5; p <0.01) and (game+Bfb)2 (t = 2.63; df = 5; p < 0.05). (b) control group: increase in EMG values during game learning (t=4.14; d / = 5 ; p<0.01); increase during (relaxation)~ (t = 2.94; df = 5; p <0.05) and (game+ relaxation)2 (t = 2.59; df = 5; p < 0.05). 3.2 Analysis o.f EEG data The mean percentage values of EEG spectral power were calculated in the theta, alpha and beta bands for all experimental subsessions and both cerebral hemispheres (Table I). In both baseline periods with first closed and then open eyes no significantly different percentage means of EEG spectral power were shown by the groups (Table 2). Also in other comparisons between both groups by Student's t test for independent samples no significant differences were revealed except for (game+ Bfb)2 vs (game+relaxation)2 where the experimental group has shown a higher alpha spectral power level (Table 2), but only in the left hemisphere. At the remaining comparisons both hemispheres showed a similar activation. Within each group the subsessions were compared with the baseline periods---open eyes (Table 3). In both groups significant decreases in alpha spectral power occurred during all the three subsessions when the subjects were engrossed in the psychomotor test. On the contrary, theta spectral power values increased significantly only during the first performance of psychomotor test. 3.3 Analysis o/HR data Heart rate mean values did not show any significant variation between groups and subsessions (Table 4). 3.4 Psychomotor trial per[ormance Both groups performed identically (Table 4). Within each group however a significant difference was revealed at the comparison by Student's t test for matched pairs as follows: (game + Bfb)2 vs (game learning): t(5)-4.17,

theta alpha beta

tbeta alpha beta

tbeta alpha beta

RIGHT HEMISPHERE

theta alpha beta

theta alpha beta

21.4(10.2) 41.8(9.6) 36.8(13.2)

Baseline EO

42.4(14.8)

beta tbeta alpha beta

18.4(7.7) 39.2(10.8)

Baseline EO

17.6(9.5) 45.4(20.4) 37.0(18.7)

Baseline EO

theta alpha

Control group

LEFT HEMISPHERE

Control group

RIGHT HEMISPHERE

Baseline EO

19.7(6.2) alpha 44.6(10.7) beta 30.7(11.2) tbeta

Experimental group

LEFT HEMISPHERE

Experimental group

20.2(6.6) 33.9(10.1) 45.9(13.3)

Baseline EC

50.2(12.5)

18.3(7.4) 31.5(9.4)

Baseline EC

16.5(8.2) 39.7(12.3) 43.8(13.7)

Baseline EC

15.9(4.0) 35.8(8.3) 48.3(11.4)

Baseline EC

Adapt. 1

Bfbl

Game + Bfbl

Adapt. 1

Btbl

Bfb2 19.8(11.7) 30.5(6.8) 49.7(12.5) Game + Bfb2

Game + Bfb2 17.9(11.0) 21.0(7.0) 61.1(10.8)

Adapt. 1

Relax 1

Game + Relax 1

Relax 1

Game+Relax 1

Game +Relax 2 22.5(8.4) 11.7(6.1) 65.8(12,2)

61.1(14.1)

Relax 2

Game + Relax 2

18.8(10.0) 17.9(12.1) 22.7(9.6) 32.4(9.5) 34.3(I1.6) 12.3(10.7) 48.8(15.6) 47.8(14.9) 65.0(18.9)

Adapt. 2

29.2(4.8) 22.2(14.6) 19.0(12.4) 26.6(8.3) 11.5(6.2) 29.6(11.9) 33.1(15.5) 13.0(9.7) 59.3(14.7) 48.2(16.8) 47.9(17.0) 60.4(17.0)

Adapt. 1

Relax 2 21.8(10.0) 28.3(7.9) 50.9(12.6)

Adapt. 2 19.5(9.7) 27.5(8.5) 53.0(10.0) Game

51,9(9.8)

59.3(11.0) 53.4(9.8)

29.5(4.2) 20.1(8.3) 18.8(10.2) 25.2(11.5) 11.2(5.3) 26.5(11.0) 29.3(9.7) 13.7(8.8)

Game

27.5(7.4) 18.1(12.2) 18.6(13.5) 19.7(14.2) 14,2(10.5) 32.7(11.4) 29.5(15.7) 20.8(10.9) 58,3(10,6) 49.2(19,7) 51,9(21.8) 59.5(19.8) Adapt. 2 Bfb2 Game+Bfb2 20.4(15.2) 19.2(12.3) 21.7(12.8) 38.6(14.7) 37.5(9.5) 21.5(10.2) 41.0(21.8) 43.3(18.8) 56.8(16.9)

Game

Adapt. 2 17.6(11.9) 31.6(6.9) 50.8(15.4)

25.2(4.3) 17.0(13.5) 19.2(12.4) 22.1(14.7) 12.4(7.2) 30.4(8.3) 26.7(10.0) 17.9(8.0) 62.4(10.3) 52.6(10.4) 54.1(12.7) 60.0(13.2)

Game

Table 1, EEG percentage mean values

19.4(10.4) 31.5(12.9) 49.1(16.7)

Adapt. 3

Adapt. 3 17.8(11,6) 29.8(15,4) 52.4(13,1)

41.2(17.3)

4o.6(18.4)

18.2(11.3)

Adapt. 3

Adapt. 3 14.3(16.4) 48.4(20.3) 37.3(18.6)

t.,.o

g

,.s

g, g.

t values theta in alpha bands beta Control group

Experimental group

(*)p < 0.05 RIGHT HEMISPHERE

t values theta in alpha bands beta Control group

Experimental group

LEFT HEMISPHERE

0.69 0.35 0.02 Baseline EC

Baseline EC

0.29 0.78 0.81 Baseline EC

Baseline EC

0.79 0.81 0.24 Baseline EO

Baseline EO

0.64 0.77 0.25 Baseline EO

Baseline EO

0.43 0.49 0.13 Game

Game

1.59 0.30 0.46 Game

Game

0.48 0.42 0.09 Adapt. 1

Adapt. 1

0.44 0.63 0.31 Adapt. l

Adapt. 1

0.07 0.36 0.23 Relax 1

Bfbl

0.06 0.41 0.31 Relax l

Bfbl

0.94 1.19 0.07 Game + Rel. 1

Game + Bfbl

0.37 0.79 0.12 Game + Rel. l

Game + Bfbl

Table 2. Comparison between Groups: EEG--Student's t (D[ = 10)

0.20 0.79 0.69 Adapt. 2

Adapt. 2

0.34 0.82 0.27 Adapt. 2

Adapt. 2

0.17 0.48 0.42 Relax 2

Bfb2

0.74 0.29 0.15 Relax 2

Bfb2

0.14 1.39 0.72 Game + Rel. 2

Game + Bfb2

0.74 2.24(*) 0.65 Game + Rel. 2

Game

0.17 0.90 0.73 Adapt 3

0.39 1.63 1.48 Adapt 3

Adapt 3

g~

theta alpha beta

RIGHT HEMISPHERE

theta alpha beta

RIGHT HEMISPHERE

(*)p<0.05 (**)p<0.Ol

theta alpha beta

LEFT HEMISPHERE

CONTROL GROUP

theta alpha beta

LEFT HEMISPHERE

EXPERIMENTAL GROUP

2.77 (*) 4.73 (**) !.69

0.31 0.71 0.27

0.40 0.86 0.50

Adapt. 1

Game 3.29 (*) 4.72 (**) 1.37

0.72 1.04 0.59

2.56 (*) 3.94 (*) 1.69

Game Adapt. 1 3.96(*) 0.19 5.33 (**) 1.15 2.30 0.69

0.21 0.13 0.23

0.19 0.40 0.27

Relax 1

0.33 1.27 0.78

Bfbl 0.62 1.74 0.85

1.51 3.74 (*) 1.68

1.27 3.46 (*) 1.44

Game + Relax 1

0.49 2.87 (*) 1.63

Game+Bfbl 1.02 3.83 (*) 1.68

0.29 0.27 0.35

0.25 0.79 0.44

Adapt. 2

0.56 0.15 0.27

Adapt. 2 0.34 0.97 0.32

0.41 0.07 0.24

0.71 0.65 0.10

Relax 2

0.46 0.36 0.07

Bfb2 0.79 1.23 0.22

Table 3. EEG comparison within each group: baseline vs subsessions Student's t ( D / = 5)

0.78 3.67 (*) 2.07

0.93 4.42 (**) 2.23

Game + Relax 2

0.86 2.85 (*) 1.70

Game+Bfb2 0.59 3.41 (*) 2.04

0.16 0.43 0.39

0.09 0.24 0.30

Adapt. 3

0.31 0.12 0.29

Adapt. 0.25 1.43 1.27

¢D

=t

ft

B o R.

e~ O"

E g

UO

5.9 2.81 76.0 15.1

Baseline EO

6.3 1.8 72.6 14.9

10.8 2.18 85.3 17.2 41.08 (5.72)

Game

9.2 1.14 81.6 16.0 ~.27 (5.34)

Game

6.1 3.74 77.4 15.6

Adapt. 1

0.35

HR

Errors

0.29

EMG

0.23

0.35

1.45

6.9 2.95 74.8 15.4

Adapt. 1

0.26

0.09

Student's t (10) values--comparison between groups

EMG .X S.D. HR .X S.D. ERROR% MEAN .~ in the game S.D.

CONTROL GROUP

EMG X S.D. HR X S.D. ERROR % MEAN X in t ~ game S.D.

Baseline EO

EXPERIMENTAL GROUP

0.18

6.5 2.8 73.6 15.3

Relax 1

6.2 2.04 71.8 15.2

Bfbl

0.27

0.42

6.45(**)

11.8 1.80 83.8 18.1 31.97 (2.84)

Game + Relax 1

5.5 1.24 79.0 17.6 32.44 (2.61)

Game + Bfbl

0.37

1.21

7.3 3.15 76.1 15.0

Adapt. 2

6.4 1.56 72.6 14.8

Adapt. 2

0.45

6.14(**)

7.8 1.16 74.9 16.0

Relax 2

3.6 1.00 70.4 15.3

Bfb2

0.38

0.50

5.90(**)

10.7 2.34 82.4 17.5 26.59 (2.89)

Game + Rel. 2

4.1 0.89 77.0 16.3 27.9 (2.85)

Game+B~2

Table 4. EMG, HR, Scores: means and S.D.--Student's t values. Comparisons between groups

0.33

0.82

7.2 3.68 74.9 15.6

Adapt. 3

5.8 1.03 71.8 13.9

Adapt. 3

g

c) .7,

c3

Biofeedback monitoring-devices for astronauts in space environment p < 0.01; (game + relaxation)2 vs (game learning): t(5) = 4.26, p < 0.01. 3.5 STAU-X1 scores There was in both groups a slight tendency toward a decrease in anxiety after the experimental session. However, the comparison between groups and after treatment was not significant (Table 5). 4. DISCUSSION While the subjects did not undergo a complete EMG-feedback training but only a single session there is some evidence that learning of biofeedback technique partly occurred and moreover seemed to increase with the passing of time expanding also to subsessions where game and Bfb were implemented simultaneously. From the comparison with the control group the above learning stands out in the experimental group which shows significantly lower average and percentage EMG values in the three last subsessions when Bfb was being performed (Table 4). From the analysis of EEG data it should be emphasized that the comparison between Bfb alone ano relaxation alone did not show any significant difference, thus indicating a similar effect of both techniques on EEG activation in resting conditions. On the contrary, a significantly higher alpha rythm observed in the experimental group in aroused conditions, viz. (game + Bfb)2 vs (game + relaxation)2 seems to indicate that biofeedback is more effective than simple relaxation in keeping EEG activation lower in spite of the involvement of higher mental functioning because of the psychomotor trial (Table 2). The observation that heart rate is substantially the same in both groups and all the situations seems to indicate that a unique session of EMG-feedback is not good enough to achieve a generalization of feedback up to this somatic function. The learning of biofeedback technique does not seem to affect adversely the psychomotor performance since both groups showed almost the same scores while the comparison within each group between the first and the last game subsession reveals a progressive learning with significantly lower scores (Table 4). As to the evaluation of state anxiety both groups scored less after the experimental session (Table 5). Although the scores of the experimental group tend to lower values, the difference is not significant. Attention should be called to the fact that the present study encompassed a double-task learning as the subTable 5. STAI-XI: Comparisons between groups Experimental

Control

Before

= 32.83 S.D. = 3.92

= 33.35 t = 0.27 (n.s.) S.D. : 4.46 (Dr= 10)

After

= 31.33 S.D. = 4.84 t = 1.77 (n.s.) (Df : 5)

X=32.17 t = 0.32 (n.s.) S.D. = 4.16 (Dr = 10) t = 1.76(n.s.) (1)[ = 5)

597

jects had to learn both Bfb and psychomotor trial. In space environment there will clearly be a different situation because space mission tasks and Bfb will be thoroughly elucidated on Earth. Bearing in mind the limitations imposed by the paradigm utilized and the small number of subjects, we feel however that these findings should stimulate further investigations along these lines on the application of biofeedback along with the accomplishment of other tasks. 5. CONCLUSIONS The state-of-the-art of modern day technological miniaturization makes it possible for electronic hardware to easily comply with space setting requirements. A case in point is an elementary loop weighing a few grams attached to a muscle zone of the skull and coupled with a tone generator located on the astronaut's mastoid. Also the standard collection/amplification/transmission board system of biological data from space vehicles could be employed to pilot a Bfb device. More complex biologic functions as brain or heart rythm, blood pressure, skin temperature, etc. might be monitored and fed back as auditory or visual feedback or digitally displayed. Perhaps auditory feedback is the best-suited for simultaneous performance of multiple tasks. However, the problem with biofeedback is its intrinsic value as self-regulation technique. While some physiologic variables normally beyond the scope of consciousness can be undoubtedly brought under control with biofeedback, it remains to be seen which role is played by some complex cognitive processes as placebo effect, expectancy, demand characteristics, etc. Finally, the application of biofeedback in space environment should not be felt by the astronaut as intrusive but as bridging the gap at the man/machine interface.

Acknowledgements--The authors gratefully acknowledge the expert technical assistance and intellectual collaboration of Mr. R. Toil. REFERENCES

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