Psychophysiological investigations in essential hypertensives

Journal of Psychosomatic Research, Vol. 19,pp.251to 258.Pergamon Press,1975. Printed in GreatBritain

PSYCHOPHYSIOLOGICAL INVESTIGATIONS ESSENTIAL HYPERTENSIVES ELISABETH RICHTER-HEINRICH, KARL-HEINZ

UTA

SCHMIDT

KNUST,

WOLFGANG

IN

MUELLER,

and HELGA SPRUNG

(Received 16 April 1975) THIS

contribution presents a survey of the main results of our research work, stepwise performed during the last years with stages* of essential hypertension. Our interests have centred upon three main topics represented (1) Investigations of the personality of hypertensives. (2) The development of psychophysiological screening tests to logical studies or clinical praxis and recently. (3) The lowering of blood pressure by operant conditioning

Department Ma!ntoplcs

J=

psychophysiological patients in the early in Fig. 1. These are: be used in epidemiotechniques.

of psychophystology of hypertension

research

Diagnostic

,

Elaboration of psychophysiolog-

Testing of hypertensive personality Instrumental

Methods:

Information processing

Auto -

[ 1

I Sensitivity

Pe;;soq;sdity

]

I Reactivity

I

I

1

Neuroticism

1

Introversion

I

PERSONALITY

I

RESEARCH

With regard to the personality of hypertensives our first question was what relations exist between sensitivity, reactivity and adaptation during information processing and our second one whether special personality traits could be determined which are associated with hypertension. In order to determine the sensitivity during stimulus intake we examined absolute acoustic thresholds for the frequencies of 500, 1000,2000,4000 and 8000 Hz. The reactivity was first examined by the acquisition of a backward conditioned GSR and second by Academy of Sciences of the German Democratic Republic, Berlin, Central Institute for Research of Heart and Circulatory Regulations, 1115 Berlin-Buch, Wiltberg Str. 50 EDR. * Stages 1 and 2 according to Nitschkoff and Baumann [l]. 251

252

E. RICHTER-HEINRICH,U. KNUST, W. MUELLER, K.-H. SCHMIDTand H. SPRUNG

testing autonomic reaction patterns, blood pressure, heart rate and changes in skin potentials, at rest and under mental load. As a measure for adaptation we used the method of Feldmann [2] which tests the acoustic adaptation as a temporal change of the signal detection performance. For testing personality traits we used first of all the MPI of Eysenck and the Angst-Skala of Spreen the latter being a modification of the Taylor Manifest Anxiety Scale. In addition we tested the patients’ ability of concentration by the Konzentrationsverlaufstest (KVT) of Abels. At the 8th European conference at Knokke we presented the results that we obtained by using this testbattery with essential hypertensives and normotensives [3]. In order to evaluate the differential diagnostic valence of these methods the same testbattery was applied to hypotensives representing another cardiovascular pathological group and to phobics, mostly cardiophobics, as a group of patients with predominantly psychic symptoms. In this context we were especially interested in the following two questions: (1) Which of the test variables are specific for one of the diseases mentioned above? (2) Do extreme physiological levels of arousal correlate with extreme psychological characteristics? For details of this study see [4, 51. Here we should like to explain in a nutshell the results we obtained by an analysis of discriminance. The positions of the groups in the discriminant scheme in Fig. 2 are determined by the calculation of the two most clearly separating discriminant functions A and B. By performing additional statistical procedures we obtained an explanation of the discriminant functions. Function A mainly rises owing to an increase of the physiological variables of the mental load test and the conditioned reflex activity, to a minor degree owing to the decline of the acoustic thresholds of 500 and 8000 Hz and the reduction of acoustic adaptation. The values of function B rise with an increase of anxiety and neuroticism and a decrease of extraversion. Thus function A represents a physiological dimension of activation and function B a ‘dysthymia’ (Eysenck) dimension.

Increased

!

Neuroticism Anxiety Introversion

I Decreased- Concentration

/

I

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._ P.

Mean group values of dtscrimmont functions Aond R

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FIG. 2

Now the positions of the groups can be explained. With regard to function A hypotensives and hypertensives represent lower and higher points of the physiological arousal continuum. Phobics and normotensives occupy an intermediate position. Thus these variables are specific for hypotensives and hypertensives only. Moreover, it becomes obvious that there are close relations between a high acoustic sensitivity and a high physiological reactivity as well as a low acoustic adaptation. As a consequence the high autonomic reactivity of hypertensives is combined with a high acoustic senstivity and a low acoustic adaptation. Hypotensives show the opposite behaviour patterns. Looking at the B-function values it can be seen that both extreme physiological arousal levels, the high one of hypertensives and the low one of

Psychophysiological

investigations

in essential hypertensives

253

hypotensives in comparison with normotensives, are connected with slightly increased values of anxiety, neuroticism, introversion as well as a reduced concentration. The increase in function B is for both groups approximately homogeneous and consequently not disease specific for hypertensives or hypotensives. Thus it can be assumed that deviations from a median physiological arousal level independently from the direction of these deviations are associated with tendencies to abnormal psychological behaviour. The findings in normal Ss. showing in both functions a medium position support this hypothesis, but our results in phobics did not confirm it. Pathologically high anxiety and neuroticism (function B) by which the phobics are clearly differentiated from the other groups are not paralleled by a corresponding extremely physiological arousal level (function A). Possibly phobics respond only to certain key stimuli, being typical for their phobic condition, with an increased physiological activation. This is referred to by van Egeren cf al. [6], who tested autonomic reactions to the visual imagination of neutral and threatening stimuli. Lader [7] however, observed in phobics when presenting sound stimuli significantly more skin potential changes per min than in normal Ss. Our results showing that both the hypotensives and hypertensives have the same slightly increased average values with respect to introversion, neuroticism and anxiety, the latter two can be designated as basic neurotic traits, support the view of many authors that there exists no specific hypertensive personality. Therefore we wanted to know, whether it would be possible to find different representative groups of hypertensives characterized by similar personality traits. As a first step we examined 75 hypertensives with the Freiburger Persiinlichkeits-Inventar of Fahrenberg and Selg [8] by means of which 12 personality traits represented in Fig. 3 are measured. By means of a cluster analysis we could single out 4 clusters. (For this we used the ‘agglomerative clustering method’ after modifying the measuring values and calculation of a matrix of Euclidean distances.) The values in the single clusters express standard nine-values. Thus the grey middle columns (values 4-6) include 54% of normals that is not neurotic subjects. Cluster I includes 27 Ss., that means about one third of the whole group. This cluster comprises dysthymics. Increased nervousness, inhibition, depression and emotional lability is combined with low extraversion, i.e. introversion. Extreme neurotic traits are an exception in our group of hypertensives and are only to be found with the 6 patients of cluster 2. Ss. in this cluster show extreme values in most personality traits measured. In cluster 3 and 4 most values are in the middle column. These 2 clusters differ only in so far as the patients in cluster 3 show more self-confidence and calmness while patients in cluster 4 are more psychosomatically disturbed and irritable. The obtained results can be summarized as follows: Clearly neurotic traits are only to be found in 44% of the cases (cf. clusters 1 and 2). It is conspicuous that values of an increased nervousness occur in three clusters, i.e. psychovegetative disturbances are evident with most patients. We could verify these results in another group of 75 hypertensives. In a group of 75 normotensives it was necessary to calculate a bigger number of clusters in order to get homogeneous subgroups. The two hypertensive groups and the normotensives are homogeneous with respect to age, sex and profession. Our only selection criterion was the blood pressure level. Therefore it can be assumed that the 4 obtained personality structures of hypertensives are associated with the heightened blood pressure,

254

U. KNUST, W. MUELLER,K.-H. E. RICHTER-HEINRICII,

SCHMIDT and H. SPRUNG

FPI Cluster analysis Hypwtensives (n=75) Cluster n=27

I

Cluster2 n=6

Cluster3 n-23

Cluster4 n-19

Depressivity

Calmness Dominance InhIbition Frankness IO Extraverswn

II

Emotional

IabIlity

12 Moscullmty

Fm.

although these conclusions psychosomatic diseases.

3

must be verified

SCREENING-TEST

by investigations

of groups

with other

DEVELOPMENTS

Starting from the fact that the human being in highly industrialized countries is not so much subjected to purely physical strain but to psychological one and that referring to Baumann [9, lo] psychological stress is one of the main factors of the pathogenesis of essential hypertension we decided to develop a psychophysiological screening device for ascertaining hypertensives. At first we developed a so-called ‘Feinscreening-Test’ which makes possible the classification of 3 diagnostic groups, namely normotensives, hypertensives stage 1, and hypertensives stage 2. With respect to the positive results we got with this method [l I] we developed secondly a so-called ‘Grobscreening-Test’, which should be constructed in such a manner that it can be used as a criterion of selection by clinicians in their daily praxis and in epidemiological studies respectively. The test should comply with situations in daily life and practicable with regard to the expenditure of work necessary to perform the examination and to analyze the data obtained. The test consists of three elements: the initial rest phase of 3 nun, a load phase of 5 mitt, in which the Ss. have to solve arithmetical tasks, and a final rest phase of 3 min. During this period of 10 min the systolic and diastolic BP are measured per minute. Figure 4 shows the mean values and standard deviations for the groups of normotensives and hypertensives with stage 1. The differences between the mean values of the single measurements are very significant (p < 0.001). It is to be seen that the regions in which the standard deviations overlap are very small for both the systolic and diastolic BP. It could be verified, that in spite of higher initial values the hypertensives showed higher increases of BP during arithmetical tasks than the normotensives. In order to make a diagnostic classification of individual subjects possible a discriminant analysis was used. Figure 5 shows the results of this analysis. The patients position are determined by calculation of discriminant function A. The classification of the individual patients permits two statements : (1) The straight line shows into which group the patient belongs with maximum probability. (2) The circles show which diagnosis are possible, if the classification must be in agreement in 95 % with the clinical diagnosis.

Psychophysiological

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in essential hypertensives

255

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FIG. 4

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FIG. 5 Thus the 70 normotensives were all correctly classified with maximum probability. In the groups of hypertensives 14 mis-classifications occurred, i.e. from 95 patients 14.7% were classified with maximum probability as normotensives. This corresponds to a correct classification of 85.3%. This analysis was performed under the aspect whether it was possible to achieve a sufficient discrimination with less than 20 variables. For this the single variables were weighted according to their

256

E. RICHTER-HEINRICH, U. KNUS~, W. MOLLER, K.-H.

SCHMIDT and H. SPRUNC;

expenditure of time, i.e. the last systolic BP value was weighted with the cost factor 10 and the first with the cost-factor 1. The weighting of the diastolic values was done analogously. The number of the required variables for optimum discrimination of the two diagnostic groups was ascertained b) a stepwise ‘building-up process’. We ascertained that for discriminating the two groups with the above mentioned validity 10 variables are necessary. These 10 variables are the first 5 systolic and diastolic BP-values. In this way half the time necessary for performing the test was saved which essentially facilitates the practical application of the test as a screening device. OPERANT

CONDITIONING

OF

BLOOD

PRESSURE

The demonstrations of Miller [12] and others showing that autonomic behaviour can be modified by operant conditioning offer an opportunity to lower the blood pressure (BP) of hypertensives by such procedures. Positive results in lowering either the systolic or diastolic BP in hypertensives by using biofeedback procedures are reported by several authors [l3-151. In view of this we performed such experiments with hypertensives. Our patients were studied in 4 daily sessions with a 1 day break after the 2nd session. In each session blood pressure was measured automatically each min. All Ss. were given 6 initial adaptation trials, followed by twenty conditioning trials. When the systolic blood pressure decreased below a determined critical value (the highest value of the last 3 measurements) the Ss. were rewarded by showing them slides with landscapes, animals or flowers. These Ss. were 30 patients with mild hypertension without medicamentation. 20 of them were given an operant feedback training of blood pressure in 4 sessions, the other ten served as a yoked control group. Each S. of the control group was paired with a S. of the training group which had an equal BP initial value. The control group was given the same instructions as the conditioning group but was reinforced independently from their own BP levels as the paired Ss. of the training group. Figure 6 shows the diRerent trends in BP for the conditioning group and the control one. Each point represents an average value per group, 5 trials each.

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of fwe test trlols

mean values

Course of sysfolicBP in 20potients reworaed for decreases I” systolG3Pand 20 pabents of Q yoked control group

FIG. 6 The data were analyzed to find out first the differences within groups by a f-test for correlating samples and second differences between groups by an analysis of variance. On all 4 days the conditioning group showed significant decreases of systolic BP. The average value from the first to the last day is 21 mm Hg, ranging from 11 to 37 mm Hg. From day to day the decreases became smaller which is possibly due to the fact that the initial values, too, decrease from day to day i.e. from 144 to 123 mm H

Psychophysiological

*

investigations

Day

+

in essential

257

hypertensives

I

Day 4

-2 -~ I

The control group is clearly distinguished from the conditioning group and shows only in the first session a significant BP decrease, which however is smaller than that of the conditioning group. On the other three days there was no significant change in blood pressure, neither in the initial levels nor in the course of training, so that the decrease on the first day can be interpreted as habituation. Furthermore we registered the respective values of diastolic BP and heart rates of the conditioning group. The changes during the daily sessions were for both variables in no case significant. For receiving comparable results we took the initial values of the first session as lOO’% and computed the changes during conditioning in % for all 3 systems. Figure 7 shows the results of day 1 and day 4. It can be seen, that diastolic BP and heart rate are closely related, especially on day 4. The changes in systolic BP are much more marked and show systematical decreases from phase to phase. In addition we compared the learning curves of the patients who were classified as highly anxious in the Manifest Anxiety Scale of Taylor with those of patients with medium anxiety (Fig. 8). On both days the initial values of both groups do not significantly differ. But the group with medium anxiety shows during 4 sessions an average decrease of 22 mm Hg while that with high anxiety shows

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medium anxiety group (n= 12)

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FIG. 8

scores

258

E. RICHTER-HEINRICH, U. KNUST, W. MULLER, K.-H.

SCHMIDT and H. SPRUNG

an average decrease of only 12 mm Hg. This difference is significant. These last result is to be regarded as preliminary finding which must be verified by investigating larger groups of patients.

From these experiments and those of Miller, Shapiro [16], Benson, etc. can be concluded that blood pressure changes can be learnt. The view held nowadays [17] that positive results in lowering blood pressure by operant feedback procedures are possibly due to placebo effects, such as the psychotherapeutic relationship between experimentator and patient could be excluded by our rigorous control condition, although cognitive factors, motivation, etc. are as important in our experiments as in human conditioning experiments in general. REFERENCES

5. 6. 7. 8. 9.

10. 11. 12. 13. 14. 15. 16. 17.

NITSCHKOFF ST. and BAUMANN R. Die klinischen Schweregrade des arteriellen Hypertoniesyndroms. I. Dte. GesundhWes. 23, 4 (1968); II. Dte. Gesundh Wes. 23, 49 (1968). FELDMANN H. Untersuchungen zum Phsnomen der H&adaptation. Arch. Ohr.-,Nas.-u. KehlkHeilk. 172,341 (1958). RICHTER-HEINRICH E. Psychophysiological personality patterns of hypertensive and normotensive subjects. Psychother. Psychosom. 18, 332 (1970). RICHTER-HEINRICH E., BORYS M., KREIHS W., CURIO I. and LAUTER J. A contribution to Diagnostic Differentiation of Certain Pathological Groups by Multivariate Psychophysiological Tests. Stud& Psychologica XVI, 51 (1974.) RICHTER-HEINRICH E., BORYS M., SPRUNG H. and L~~UTER J. Psychophysiologische Reaktionsprofile von Hypo- und Hypertonikern. Dte. Gesundh Wes. 26, 1481 (1971). VAN EGEREN L. F., FEATHER B. W. and HEIN P. L. Desensitization of Phobias: Some Psychophysiological Propositions. Psychophysiology 8 (1971). LADER M. H. Palmar skin conductance measures in anxiety and phobic states. J. Psychosom. Res. 11,271 (1967). FAHRENBERG J. and SELG H. Das Freiburger Persiinlichkeitsinventar (FPI)-Handanweisung. Giittingen 1970. BAUMANN R. Theoretische und klinische Aspekte der zerebroviszeralen Regulationskrankheit arterielle essentielle Hypertonie. I. Dfe. Gesundh Wes. 29, 673 (1974); II. Dte. Gesundh Wes. 29, 721 (1974). BAUUANN R. Stress-SensibilitBt und Adaptation. Z. In% Med. (in press). RICHTER-HEINRICH E. and L~~KJTERJ. A Psychophysiological Test as Diagnostic Tool with Essential Hypertensives. Psychother. Psychosom. 13, 153 (1969). MILLER N. E. Learning of visceral and glandular responses. Science 163. 434 (1969). MILLER N. E. Postscript, in Current Status of Physiological Psychology/ Readings (Edited by SINGH D. and MORGAN C. T.). Brooks-Cole, Monterey, Calif. (1972). BENSON H., SHAPIRO D., TURKSY B. and SCHWARTZ G. Decreased systolic blood pressure through operant conditioning techniques in patients with essential hypertension. Science 173, 740 (1971). ELDER S. T., RUIZ Z. R., DEABLER H. L. and DILLENHOFFNER R. L. Instrumental conditioning of diastolic blood pressure in essential hypertensive patients. J. Appl. Behav. Anal. 6, 377 (1973). SHAPIRO D., SCHWARTZ G. E. and TURSKY B. Control of Diastolic Blood Pressure in Man by Feedback and Reinforcement. Psychophysiol. 9, 296 (1972). PICKERING T. G. and MILLER N. E. Blood Pressure Control and Conditioning. Paper given 10th Europ. Conf. Psychosom. Res., Edinburgh (1974).