- Email: [email protected]
Effects of cold and mental stress on finger temperature in vasospastics and normal Ss
Behoc. Res. Thu. Vol. 22. No. 5, pp. 471-476. Printed in Great Britain. All rights reserved
1984 Copyright
0
0005-7967/84 $3.00 + 0.00 1984 Pergamon Press Ltd
EFFECTS OF COLD AND MENTAL STRESS ON FINGER TEMPERATURE IN VASOSPASTICS AND NORMAL Ss KENNETHHUGDAHL,‘* KARL-OLOV FAGERSTR~~M’ and CLAES-G~~RAN BROB~~CK’ ‘Department of Psychology, University of Uppsala, Box 227, S-751 04 Uppsala, Sweden 2Psychiatric Research Center, UllerHker Hospital, S-750 17 Uppsala, Sweden
(Received31 Ucfober 1983) Summary-The present experiment studied the effects of mental and cold stress on finger temperature in 9 females suffering from peripheral vasospastic attacks (Raynaud’s disease; RD group) and 9 female controls. Each S sat in a 0°C cold-storage room for 15 min, on 2 separate days. In one condition they were required to count backwards aloud under threat of electric shock to the hand. Finger temperature, pulse rate and subjective ratings of stress were recorded. A significant interaction with time and mental stress was observed only for the Control group with decreased finger temperature late in the session. Pulse rate was significantly elevated during the cold + mental-stress condition compared to the cold-only condition in the Control group, but not in the RD group. Subjective ratings of stress increased for both groups during the cold + mental-stress condition, with no significant difference between the groups.
INTRODUCTION
Despite the claim of Maurice Raynaud (1862) that Raynaud’s disease (RD) should be regarded as a psychosomatic disease, the role of psychological factors such as stress and emotion has generally been underemphasized, at least in the medical literature [see, for instance, Coffman (1971) and Guyton (1976)]. Instead emphasis is placed on cold as the primary eliciting factor for vasospastic attacks. Although the effect of cold in RD is relatively well-established, with reduced blood flow in the digits after cooling (Bollinger and Schlumpf, 1976; Holling, 1972) accompanied by reduced pressure in the digits (Nielsen, Sorensen and Olsen, 1980; Thulesius, Brubakk and Berlin, 1981), the exact effects of emotions on RD are not clearly understood (Freedman, Lynn and Ianni, 1982). Behaviorally-oriented authors have suggested, however, that in some patients symptoms may be precipitated by emotional stress (e.g. Freedman et al., 1982; Sedlacek, 1979; Surwit, 1982; Surwit, Williams and Shapiro, 1982; FagerstrGm and Melin, 1982). One of the most frequently cited papers supporting the notion of emotions as part of the etiology in RD, is the report by Mittelmann and Wolff (1939). They interviewed RD patients about stressful events in the patients’ daily experiences and found significant drops in finger temperature in an otherwise normally tempered environment (around 22°C) (see also Graham, 1955). Moreover, in an attempt at replication Freedman et al. (1982) found reduced finger temperature when ‘imagery scripts’-as defined by Lang (1979 j-with emotional contents were imagined by RD patients during 2-min periods. However, an important factor in these studies is that all tests were conducted in settings with a normal indoor temperature. To our knowledge no study has explored the differential effects of mental and cold stress on individuals suffering from RD, which was the main purpose of the present experiment.. The starting point of this study was the behavior shown by clinical Ss in a previous treatment study in our laboratory (Fagerstrsm and Melin, 1982). When the Ss were told they would be exposed to cold as part of treatment evaluation, they all claimed that they would show massive vasospastic attacks. However, no attacks occurred, although recording of attacks in the home environment showed several attacks per week in some Ss. It was therefore suggested that perhaps the presence of clinicians, and the expectation that the patients were under expert treatment created a relaxing nonemotional atmosphere. This in turn would inhibit the vasospastic behavior despite exposure to a cold environment. Thus, mere exposure to *To whom all reprint requests should be addressed. 471
472
KENNETH HUGDAHL et al
cold stress in an otherwise psychologically relaxing environment may elicitation of a vasospasm. The purpose of the present investigation, therefore, was to investigate mental stress (backwards counting) in a cold environment in individuals peripheral vasoconstriction (RD group), compared with a group of (Control group). Subjects
not be sufficient for the the additional effects of suffering from attacks of nonvasospastic controls
METHOD
RD group. Twelve female Ss suffering from vasospasms and digital pallor were recruited from two sources: a group of waiting-list patients from a previous treatment study (Fagerstrom and Melin, 1982) (2 Ss); and a group of nursing students (10 Ss). The waiting-list and nursing student Ss underwent the same screening procedure. An advertisment on a nursing school notice board asked students suffering from RD symptoms to contact the authors. All individuals reporting were then interviewed on the telephone by the experimenter concerning the nature and severity of symptoms. In order to be selected for further testing, each individual had to report frequent experiences of attacks of blanching in the digits when exposed to cold during the last year. The investigation was described as basic research and not specific treatment for RD. Information about the study placed particular emphasis on the low temperature they would be exposed to and their oral consent was obtained. A final screening was then made upon arrival at the clinic where each S was asked to fill out a questionnaire containing items relevant for the diagnosis of secondary RD (i.e. experiences with diabetes, vibrating working tools, noisy environments, previous experiences of frostbite and other injuries to the hands). To be included in the RD group, Ss had to respond negatively to all of these items. A second group of items in the questionnaire concerned specific symptoms. The S marked a ‘yes’ or ‘no’ on seven different questions about: (1) experiences with digital numbness, (2) attacks of 5-10 min duration with fingers turning white, (3) attacks of more than 10 min duration, (4) attacks during wintertime, (5) attacks during summertime, (6) fingers turning red upon release of spastic attack and (7) trophic disturbances. Finally they marked the exact localization of the most afflicted area(s) on a drawing of the palmar and dorsal parts of the left and right hand and fingers. In order to be included in the study each S had to indicate a ‘yes’ on at least three of the seven items. No attempt was made to identify signs of underlying circulatory pathology in the RD group. Thus, the present data do not illuminate the recent discussion in the literature concerning the distinction between idiopathic RD and Raynaud’s phenomenon (see for instance Mendowitz and Naftchi, 1959: Surwit et al., 1982). Three Ss in the RD group were excluded since they failed to pass the criterion of at least three specific symptoms. Thus, only 9 Ss participated in the study. The age ranged between 20-55 yr with a mean of 29 yr. Mean experience of attacks was 9.9 yr. Control group. The nonRD controls were 9 female psychology students at the University of Uppsala without any signs of vasospastic disorder. Their age ranged between 19-47 yr with a mean of 24.0 yr. Apparatus
Finger temperature was monitored by a standard fine-graded ( + O.S’C) laboratory mercury thermometer, with a flat (3 x 3 mm) sensor, which was adequate for the expected large change in temperature. The sensor was not completely shielded from the ambient room temperature, but it was assumed that any measurement error due to this factor should be constant between groups and conditions. Furthermore, the thermometer and the sensor were placed on insulating material to protect them from the cold surface of the table inside the cold-storage room where the S rested the monitored hand during the experiment. To validate effects of the mental-stress condition, pulse rate was continuously measured by photoelectric plethysmography. A fingerstall containing an infrared light source and a phototransistor was connected to a small 115 x 65 x 25 mm portable pulsimeter for continuous recording and display of the pulse rate. Each pulse wave in the digit was converted to a voltage pulse which was fed to a condenser with a constant leakage. Charging of the condenser was then proportional to pulse-wave frequency, and shown analogously on a meter display. The range of the meter was 30-200 bpm. The fingerstall was connected to the meter by a 50 cm long ‘telephone cord’.
Mental
stress and Raynaud’s
disease
473
Shock electrodes, used in the mental-stress condition were two 15 x 15 mm flat Ag electrodes (ordinarily used with a standard TNS apparatus). The shock electrodes were not connected to any equipment and the wires were hidden from the S, who was told that they were connected to an electric-shock generator. The cold-storage room, where the experiment was run, had a constant 24 hr temperature of 0°C. The room was about 2 x 4 m and located in the basement of the building. It was kept cold by freezing elements and normally used for storage of medical utensils that required refrigeration. Design and dependent measures
The basic design was a 2 x 2 split-plot factorial (Kirk, 1968), with groups (RD vs Controls) and stress manipulation (cold stress vs cold + mental stress). The second of these two factors involved repeated measurement on each S. In the statistical analysis a third factor, minutes (60 set), also with repeated measurement, was added. The main dependent measure was change in finger temperature from initial baseline over time in the 0” cold environment. Temperature data were collected once every 60 set by visual inspection of the thermometer. Readings of pulse rate were also taken once every 60 sec. Finally, subjective ratings of stress were taken immediately after each session. Ss made their ratings by marking with a pen the appropriate number on a 5-point scale ranging from 1 to 5, with 1 equal to ‘completely calm’, 5 equal to ‘very stressed’ and a marking of 3 as ‘neither calm, nor stressed’. Procedure
After arriving at the hospital, all Ss were taken to a waiting room in the Smoking-Withdrawal Clinic, close to the cold-storage room, where outdoor clothing was removed and they were asked to sit down and relax. In addition the RD Ss were asked to fill out the symptoms questionnaire. Then the sensor of the thermometer was taped to the tip of the third finger of the left hand in the Control group, and to the tip of the most afflicted finger in the RD group. The tape was wrapped loosely around the finger in order to avoid mechanical vasoconstriction. The temperature in the waiting room was between 20-22°C. Ss were told that a stabilized finger temperature had to be reached before they could go down to the cold-storage room. This criterion was set at temperature increases of less than 0.5-l .O”C during the last 2 min. It usually took 10-l 5 min before the criterion was met. The S then walked down to the cold-storage room together with the experimenter. A first reading of the thermometer was made immediately after the S was put into the cold-storage room. This starting value is used as the ‘baseline’. All scores during the 15 min the Ss sat in the cold-storage room each session are expressed as deviations from this baseline. Ss as well as the experimenter were seated on regular stools with an insulated chair cushion. The fingerstall for the measurement of the pulse rate was clipped to the left thumb, and the shock electrodes fastened with adhesive collars to the dorsal part of the right hand. The S sat beside a small table with an insulating cover, on which she rested the hand which was used to measure temperature. The experimenter sat behind the S, and could see the pulsimeter on the table. The scale of the thermometer and the pulsimeter were visually shielded from the Ss. In the cold-only condition Ss simply sat for 15 min in the storage room. In the cold + mental-stress condition they were in addition required to count aloud backwards in steps of 17 from 1500 during the 15 min as fast as they could. If the counting went too slowly (according to some criterion known only to the experimenter) they were told that they would receive an electric shock to the hand. No shocks were given. Subjective ratings of stress were taken immediately after each 15 min session. A session lasted all in all about 40-45 min. All Ss received the two conditions (cold stress vs cold + mental stress) on two different days. Order of presentation of condition was counterbalanced within each group. RESULTS Finger temperature
All scores were subjected to a minutes x conditions x groups analysis of variance. Because the initial starting temperature (baseline) significantly differed between the groups [F( 1.16) = 20.22,
KENNETH HUGDAHL et al.
474
a5 r
B75:Q+_
.c
0 -20
0
I 5
I 10
70 -
I 15
-‘\,
I 1
ml” Fig. 1. Mean change in finger temperature from initial baseline temperature as a function of minutes for the two groups during both conditions. RD group: a, cold only; 0, cold + mental stress. Con-
I
I
2
3
I
I
4
5
Blocks of 3 mtn Fig. 2. Mean change in pulse rate (expressed as bpm)
as a function of minutes for the two groups during both conditions. Symbols as in Fig. 1.
trol group: A, cold only; A, cold + mental stress.
MS, = 14.15, P < 0.011 all scores for all Ss are expressed as change scores for each minute from the initial starting temperature. The mean starting temperature was 22.57 and 22.06”C for the RD cold-only and cold + mental-stress conditions, respectively. The corresponding values for the Control group were 26.83 and 29.06”C. Average change in temperature (“C) from baseline as a function of minutes for the two groups and conditions is shown in Fig. 1. The three-way interaction of minutes x conditions x groups was significant [F( 14,224) = 4.17, MS, = 1.52, P < 0.01 (see Fig. l)]. To evaluate the three-way interaction, the simple interaction effects of minutes x conditions were computed separately for the RD and the Control group (Kirk, 1968, p. 305f). This showed a significant interaction for the Control group, but not for the RD group [F(14,224) = 5.29, MS, = 1.52, P < 0.05, and F = 1.22, NS, respectively]. Figure 1 shows increasing differences between conditions over time for the Control group, with larger drops in finger temperature in the cold + mental-stress condition than in the cold-only condition late in the session. Early in the session there is, however, a nonsignificant trend for the RD group cold + mental-stress condition to drop mostly. Thus, the results for finger temperature showed a significant 15 minutes x condition interaction only for the Control group, with lower finger temperatures in the cold + mental-stress condition. Pulse-rate
data and subjective
ratings
Mean pulse rate as a function of time and conditions for the two groups is shown in Fig. 2. Note that the data are plotted in five blocks of 3 min each. However, the statistical analysis was performed on 15 min. The pulse-rate data were evaluated in a 2 x 2 x 15 (RD vs Control groups; cold vs cold + mental stress; and minutes) split-plot factorial analysis of variance. The interaction of condition x groups was significant [F( 1,16) = 6.11, MS, = 40.10, P < 0.051. Follow-up tests with t for dependent scores for the comparisons between the cold + mental-stress
Table I. Mean subjective ratings (i-5) of mental stress experienced in both groups during the cold-only and the cold + mental-stress condittons RD group (vasospastics)
Control group
stress
3.5 (0.92)”
3.1 (0.98)
Cold stress
1.4 (0.73)
1.2 (0.8 I )
~_.
~.
Cold + mental
‘Standard
deviation
Mental stress and Raynaud’s disease
475
and cold-only conditions separately for each group showed a significant difference only in the Control group [t(8) = 3.96, P < 0.011 but not in the RD group [t(8) < 1, NS]. Mean subjectives ratings of stress experienced by the two groups during exposure to the two types of stress are seen in Table 1. The subjective ratings were evaluated in a 2 x 2 (groups x conditions) split-plot factorial analysis of variance. Table 1 shows that the ratings during the cold + mental-stress condition are about three times as large as during the cold-only condition, with no differences between the groups. This impression was statistically supported by the significant main effect of type of stress [F(1,16) = 62.17, MS, = 0.84, P < O.OOl]. DISCUSSION The present study has shown increased peripheral vasoconstriction as mediated by lowered finger temperature to significantly occur only in the Control group, during a 15 min session when confronted with a mentally stressing task in a cold environment. the follow-up of the significant three-way interaction of minutes x Furthermore, conditions x groups suggested that time and stress seems to affect finger temperature more over time in nonvasospastics than in vasospastic individuals. If pulse-rate data are also included, the picture essentially shows a statistically reliable increase in pulse rate only in the Control group when mental stress is added, since no significant difference was observed between conditions in the RD group. Looking at the subjective ratings of stress in Table 1, it is obvious that there were no differences between the groups in experienced mental stress. Both groups showed increased ratings during the cold -t mental-stress condition. Thus, there is no reason to believe that the groups differed in subjectively experienced arousal as a function of the counting task. As such the present data do not wholly replicate previous case studies (Mittelmann and Wolff, 1939; Freedman et al., 1982) suffering from RD, where subjective rehearsal of emotionally stressful events has been shown to produce finger-temperature changes. Instead, the present results suggest that such a pattern of response is observed only in a group of nonvasospastic individuals when confronted with the same kind of cognitively demanding tasks. In fact, Fig. 1 reveals that the largest drop across time in finger temperature is shown by the Control Ss in the mental-stress condition when initial differences are corrected for. Thus, it cannot be concluded that a lowered finger temperature in a mentally stressful environment is an idiosyncratic characteristic of RD, since a greater response was seen in the nonvasospastic controls. The hypothesis of emotionality as a mediating mechanism in RD is therefore not supported by the present findings. An interesting finding in the present study is the apparently different cardiac pattern shown by the two groups in the cold + mental-stress condition. Acknowledging that the groups did not differ in subjectively experienced mental stress, it may be interesting to note that the higher subjective ratings in this condition were accompanied by a significant increase in pulse rate only in the Control group. Following the work of Obrist (e.g. Obrist, Howard, Lawler, Galosy, Meyers and Gaebelein, 1974) that an increase in heart rate during an avoidance situation (like fast counting to avoid shock) may be expected during efforts to actively cope with the situation, it should be noted that this pattern is absent in the RD group. In conclusion then, the present results have shown that both individuals suffering from vasospasms and normal controls respond with vasoconstriction in the fingers when mentally stressed in a cold environment. The Control Ss however showed larger changes in finger temperature over time in the mental-stress ‘condition than did the RD Ss. Although both groups showed equal increases in subjective ratings of stress in the cold + mental-stress condition, only the Control group also exhibited an increased pulse rate during this task. It is at present unclear why the RD group was inferior to the Controls in response of finger temperature to mental stress. One alternative is that the stress of anticipating and experiencing cold was much greater for the RD Ss compared to the Controls. A second possibility is that the differences between the groups are due to a more effortful performance of the task in the Control group, which affected the autonomic measures. This last possibility can not be ruled out on the basis of the present data, and may serve as an impetus for future research. This may have produced the seven degrees lower initial temperature for RD Ss compared with the controls in the cold + mental-stress, condition. We may thus have encountered a ‘floor effect’ where a further decrement in temperature cannot be regarded as physiologically equivalent.
476 Acknowledgement-This Humanities and Social
KENNETH HUGDAHL er al.
research was supported by a grant Sciences to Kenneth Hugdahl.
(Dnr
151182) from the Swedish
Council
for Research
in the
REFERENCES Bollinger A. and Schlumpf M. (1976) Fingerblood flow in healthy subjects of different age and sex and in patients with primary Raynaud’s disease. Acta chir. stand. (Suppl.) 465, 42-47. Coffman J. D. (1971) Diseases of the peripheral vessels. In Textbook OJ Medicine (Edited by Beeson P. and McDermott W.). Saunders, Philadelphia, Penn. Fagerstrom K.-O. and Melin B. (1982) A placebo controlled behavioral treatment of peripheral vasospasms with a one year follow up. Unpublished manuscript. Freedman R. R., Lynn S. J. and Ianni P. (1982) Behavioral assessment of Raynaud’s disease. In Assessment Srrategies in Behauioral Medicine (Edited by Keefe F. J. and Blumenthal J. A.). Grune & Stratton. New York. Graham D. T. (1955) Cutaneous vascular reaction in Raynaud’s disease in states of hostility. anxiety and depression. Psychosom. Med. 17, 201. Guyton A. C. (1976) Textbook of Medical Physiology. Saunders, Philadelphia, Penn. Holling H. E. (1972) Peripheral Vascular Diseases: Diagnosis and Manugemenr. Lippincott, Philadelphia. Penn. Kirk R. E. (1968) Experimental Design: Procedures for the Behavioral Sciences. Brooks/Cole, Belmont, Calif. Lang P. J. (1979) Emotional imagery and visceral control. In Clinical Applications of Biofeedback (Edited by Gatchel .. _ R. J. and Price K. P.). Pergamon Press, New York. Mendowitz M. and Naftchi N. (1959) The dieital circulation in Ravnaud’s disease. Am. J. Cardiol. 4. 580-584 Mittelmann B. and Wolff H. G. (i939)‘Affective states and skin temperature: experimental study of subjects with cold hands and Raynaud’s syndrome. Psychosom. Med. 1, 271-292. Nielsen S. I., Sorensen C. J. and Olsen N. (1980) Thermostated measurement of systolic blood pressure on cooled fingers. &and. J. c/in. Lab. Invest. 40, 683-687. Obrist P. A., Howard J. L., Lawler J. E., Galosy R. A., Meyers K. A. and Gaebelein C. J. (1974) The cardiac somatic interaction. In Cardiovascular Psychophysiology (Edited by Obrist P. A.. Black A. H.. Brener J. and DiCara L. V.). Aldine, Chicago, Ill. Raynaud M. (1862) De 1’Asphyxie Locale et de la Gang&e Symktique des Extr6mifiCs. Rigoux. Paris. Sedlacek K. (1979) Biofeedback for Ravnaud’s disease. Psvchosomutics 20. 535-541. Surwit R. S. (1982) Behavioral treatment of Raynaud’s syndrome in peripheral vascular disease. J. con&f. clin. Psychol. SO, 922-933. Surwit R. S., Williams R. B. Jr and Shapiro D. (1982) Behavioral Approaches to Cardiocascular Disease. Academic Press, New York. Thulesius O., Brubakk A. and Berlin E. (1981) Response of digital blood pressure to cold provocation in cases with Raynaud’s phenomenon. Angiologi 32, I 13-I 18.
1984 Copyright
0
0005-7967/84 $3.00 + 0.00 1984 Pergamon Press Ltd
EFFECTS OF COLD AND MENTAL STRESS ON FINGER TEMPERATURE IN VASOSPASTICS AND NORMAL Ss KENNETHHUGDAHL,‘* KARL-OLOV FAGERSTR~~M’ and CLAES-G~~RAN BROB~~CK’ ‘Department of Psychology, University of Uppsala, Box 227, S-751 04 Uppsala, Sweden 2Psychiatric Research Center, UllerHker Hospital, S-750 17 Uppsala, Sweden
(Received31 Ucfober 1983) Summary-The present experiment studied the effects of mental and cold stress on finger temperature in 9 females suffering from peripheral vasospastic attacks (Raynaud’s disease; RD group) and 9 female controls. Each S sat in a 0°C cold-storage room for 15 min, on 2 separate days. In one condition they were required to count backwards aloud under threat of electric shock to the hand. Finger temperature, pulse rate and subjective ratings of stress were recorded. A significant interaction with time and mental stress was observed only for the Control group with decreased finger temperature late in the session. Pulse rate was significantly elevated during the cold + mental-stress condition compared to the cold-only condition in the Control group, but not in the RD group. Subjective ratings of stress increased for both groups during the cold + mental-stress condition, with no significant difference between the groups.
INTRODUCTION
Despite the claim of Maurice Raynaud (1862) that Raynaud’s disease (RD) should be regarded as a psychosomatic disease, the role of psychological factors such as stress and emotion has generally been underemphasized, at least in the medical literature [see, for instance, Coffman (1971) and Guyton (1976)]. Instead emphasis is placed on cold as the primary eliciting factor for vasospastic attacks. Although the effect of cold in RD is relatively well-established, with reduced blood flow in the digits after cooling (Bollinger and Schlumpf, 1976; Holling, 1972) accompanied by reduced pressure in the digits (Nielsen, Sorensen and Olsen, 1980; Thulesius, Brubakk and Berlin, 1981), the exact effects of emotions on RD are not clearly understood (Freedman, Lynn and Ianni, 1982). Behaviorally-oriented authors have suggested, however, that in some patients symptoms may be precipitated by emotional stress (e.g. Freedman et al., 1982; Sedlacek, 1979; Surwit, 1982; Surwit, Williams and Shapiro, 1982; FagerstrGm and Melin, 1982). One of the most frequently cited papers supporting the notion of emotions as part of the etiology in RD, is the report by Mittelmann and Wolff (1939). They interviewed RD patients about stressful events in the patients’ daily experiences and found significant drops in finger temperature in an otherwise normally tempered environment (around 22°C) (see also Graham, 1955). Moreover, in an attempt at replication Freedman et al. (1982) found reduced finger temperature when ‘imagery scripts’-as defined by Lang (1979 j-with emotional contents were imagined by RD patients during 2-min periods. However, an important factor in these studies is that all tests were conducted in settings with a normal indoor temperature. To our knowledge no study has explored the differential effects of mental and cold stress on individuals suffering from RD, which was the main purpose of the present experiment.. The starting point of this study was the behavior shown by clinical Ss in a previous treatment study in our laboratory (Fagerstrsm and Melin, 1982). When the Ss were told they would be exposed to cold as part of treatment evaluation, they all claimed that they would show massive vasospastic attacks. However, no attacks occurred, although recording of attacks in the home environment showed several attacks per week in some Ss. It was therefore suggested that perhaps the presence of clinicians, and the expectation that the patients were under expert treatment created a relaxing nonemotional atmosphere. This in turn would inhibit the vasospastic behavior despite exposure to a cold environment. Thus, mere exposure to *To whom all reprint requests should be addressed. 471
472
KENNETH HUGDAHL et al
cold stress in an otherwise psychologically relaxing environment may elicitation of a vasospasm. The purpose of the present investigation, therefore, was to investigate mental stress (backwards counting) in a cold environment in individuals peripheral vasoconstriction (RD group), compared with a group of (Control group). Subjects
not be sufficient for the the additional effects of suffering from attacks of nonvasospastic controls
METHOD
RD group. Twelve female Ss suffering from vasospasms and digital pallor were recruited from two sources: a group of waiting-list patients from a previous treatment study (Fagerstrom and Melin, 1982) (2 Ss); and a group of nursing students (10 Ss). The waiting-list and nursing student Ss underwent the same screening procedure. An advertisment on a nursing school notice board asked students suffering from RD symptoms to contact the authors. All individuals reporting were then interviewed on the telephone by the experimenter concerning the nature and severity of symptoms. In order to be selected for further testing, each individual had to report frequent experiences of attacks of blanching in the digits when exposed to cold during the last year. The investigation was described as basic research and not specific treatment for RD. Information about the study placed particular emphasis on the low temperature they would be exposed to and their oral consent was obtained. A final screening was then made upon arrival at the clinic where each S was asked to fill out a questionnaire containing items relevant for the diagnosis of secondary RD (i.e. experiences with diabetes, vibrating working tools, noisy environments, previous experiences of frostbite and other injuries to the hands). To be included in the RD group, Ss had to respond negatively to all of these items. A second group of items in the questionnaire concerned specific symptoms. The S marked a ‘yes’ or ‘no’ on seven different questions about: (1) experiences with digital numbness, (2) attacks of 5-10 min duration with fingers turning white, (3) attacks of more than 10 min duration, (4) attacks during wintertime, (5) attacks during summertime, (6) fingers turning red upon release of spastic attack and (7) trophic disturbances. Finally they marked the exact localization of the most afflicted area(s) on a drawing of the palmar and dorsal parts of the left and right hand and fingers. In order to be included in the study each S had to indicate a ‘yes’ on at least three of the seven items. No attempt was made to identify signs of underlying circulatory pathology in the RD group. Thus, the present data do not illuminate the recent discussion in the literature concerning the distinction between idiopathic RD and Raynaud’s phenomenon (see for instance Mendowitz and Naftchi, 1959: Surwit et al., 1982). Three Ss in the RD group were excluded since they failed to pass the criterion of at least three specific symptoms. Thus, only 9 Ss participated in the study. The age ranged between 20-55 yr with a mean of 29 yr. Mean experience of attacks was 9.9 yr. Control group. The nonRD controls were 9 female psychology students at the University of Uppsala without any signs of vasospastic disorder. Their age ranged between 19-47 yr with a mean of 24.0 yr. Apparatus
Finger temperature was monitored by a standard fine-graded ( + O.S’C) laboratory mercury thermometer, with a flat (3 x 3 mm) sensor, which was adequate for the expected large change in temperature. The sensor was not completely shielded from the ambient room temperature, but it was assumed that any measurement error due to this factor should be constant between groups and conditions. Furthermore, the thermometer and the sensor were placed on insulating material to protect them from the cold surface of the table inside the cold-storage room where the S rested the monitored hand during the experiment. To validate effects of the mental-stress condition, pulse rate was continuously measured by photoelectric plethysmography. A fingerstall containing an infrared light source and a phototransistor was connected to a small 115 x 65 x 25 mm portable pulsimeter for continuous recording and display of the pulse rate. Each pulse wave in the digit was converted to a voltage pulse which was fed to a condenser with a constant leakage. Charging of the condenser was then proportional to pulse-wave frequency, and shown analogously on a meter display. The range of the meter was 30-200 bpm. The fingerstall was connected to the meter by a 50 cm long ‘telephone cord’.
Mental
stress and Raynaud’s
disease
473
Shock electrodes, used in the mental-stress condition were two 15 x 15 mm flat Ag electrodes (ordinarily used with a standard TNS apparatus). The shock electrodes were not connected to any equipment and the wires were hidden from the S, who was told that they were connected to an electric-shock generator. The cold-storage room, where the experiment was run, had a constant 24 hr temperature of 0°C. The room was about 2 x 4 m and located in the basement of the building. It was kept cold by freezing elements and normally used for storage of medical utensils that required refrigeration. Design and dependent measures
The basic design was a 2 x 2 split-plot factorial (Kirk, 1968), with groups (RD vs Controls) and stress manipulation (cold stress vs cold + mental stress). The second of these two factors involved repeated measurement on each S. In the statistical analysis a third factor, minutes (60 set), also with repeated measurement, was added. The main dependent measure was change in finger temperature from initial baseline over time in the 0” cold environment. Temperature data were collected once every 60 set by visual inspection of the thermometer. Readings of pulse rate were also taken once every 60 sec. Finally, subjective ratings of stress were taken immediately after each session. Ss made their ratings by marking with a pen the appropriate number on a 5-point scale ranging from 1 to 5, with 1 equal to ‘completely calm’, 5 equal to ‘very stressed’ and a marking of 3 as ‘neither calm, nor stressed’. Procedure
After arriving at the hospital, all Ss were taken to a waiting room in the Smoking-Withdrawal Clinic, close to the cold-storage room, where outdoor clothing was removed and they were asked to sit down and relax. In addition the RD Ss were asked to fill out the symptoms questionnaire. Then the sensor of the thermometer was taped to the tip of the third finger of the left hand in the Control group, and to the tip of the most afflicted finger in the RD group. The tape was wrapped loosely around the finger in order to avoid mechanical vasoconstriction. The temperature in the waiting room was between 20-22°C. Ss were told that a stabilized finger temperature had to be reached before they could go down to the cold-storage room. This criterion was set at temperature increases of less than 0.5-l .O”C during the last 2 min. It usually took 10-l 5 min before the criterion was met. The S then walked down to the cold-storage room together with the experimenter. A first reading of the thermometer was made immediately after the S was put into the cold-storage room. This starting value is used as the ‘baseline’. All scores during the 15 min the Ss sat in the cold-storage room each session are expressed as deviations from this baseline. Ss as well as the experimenter were seated on regular stools with an insulated chair cushion. The fingerstall for the measurement of the pulse rate was clipped to the left thumb, and the shock electrodes fastened with adhesive collars to the dorsal part of the right hand. The S sat beside a small table with an insulating cover, on which she rested the hand which was used to measure temperature. The experimenter sat behind the S, and could see the pulsimeter on the table. The scale of the thermometer and the pulsimeter were visually shielded from the Ss. In the cold-only condition Ss simply sat for 15 min in the storage room. In the cold + mental-stress condition they were in addition required to count aloud backwards in steps of 17 from 1500 during the 15 min as fast as they could. If the counting went too slowly (according to some criterion known only to the experimenter) they were told that they would receive an electric shock to the hand. No shocks were given. Subjective ratings of stress were taken immediately after each 15 min session. A session lasted all in all about 40-45 min. All Ss received the two conditions (cold stress vs cold + mental stress) on two different days. Order of presentation of condition was counterbalanced within each group. RESULTS Finger temperature
All scores were subjected to a minutes x conditions x groups analysis of variance. Because the initial starting temperature (baseline) significantly differed between the groups [F( 1.16) = 20.22,
KENNETH HUGDAHL et al.
474
a5 r
B75:Q+_
.c
0 -20
0
I 5
I 10
70 -
I 15
-‘\,
I 1
ml” Fig. 1. Mean change in finger temperature from initial baseline temperature as a function of minutes for the two groups during both conditions. RD group: a, cold only; 0, cold + mental stress. Con-
I
I
2
3
I
I
4
5
Blocks of 3 mtn Fig. 2. Mean change in pulse rate (expressed as bpm)
as a function of minutes for the two groups during both conditions. Symbols as in Fig. 1.
trol group: A, cold only; A, cold + mental stress.
MS, = 14.15, P < 0.011 all scores for all Ss are expressed as change scores for each minute from the initial starting temperature. The mean starting temperature was 22.57 and 22.06”C for the RD cold-only and cold + mental-stress conditions, respectively. The corresponding values for the Control group were 26.83 and 29.06”C. Average change in temperature (“C) from baseline as a function of minutes for the two groups and conditions is shown in Fig. 1. The three-way interaction of minutes x conditions x groups was significant [F( 14,224) = 4.17, MS, = 1.52, P < 0.01 (see Fig. l)]. To evaluate the three-way interaction, the simple interaction effects of minutes x conditions were computed separately for the RD and the Control group (Kirk, 1968, p. 305f). This showed a significant interaction for the Control group, but not for the RD group [F(14,224) = 5.29, MS, = 1.52, P < 0.05, and F = 1.22, NS, respectively]. Figure 1 shows increasing differences between conditions over time for the Control group, with larger drops in finger temperature in the cold + mental-stress condition than in the cold-only condition late in the session. Early in the session there is, however, a nonsignificant trend for the RD group cold + mental-stress condition to drop mostly. Thus, the results for finger temperature showed a significant 15 minutes x condition interaction only for the Control group, with lower finger temperatures in the cold + mental-stress condition. Pulse-rate
data and subjective
ratings
Mean pulse rate as a function of time and conditions for the two groups is shown in Fig. 2. Note that the data are plotted in five blocks of 3 min each. However, the statistical analysis was performed on 15 min. The pulse-rate data were evaluated in a 2 x 2 x 15 (RD vs Control groups; cold vs cold + mental stress; and minutes) split-plot factorial analysis of variance. The interaction of condition x groups was significant [F( 1,16) = 6.11, MS, = 40.10, P < 0.051. Follow-up tests with t for dependent scores for the comparisons between the cold + mental-stress
Table I. Mean subjective ratings (i-5) of mental stress experienced in both groups during the cold-only and the cold + mental-stress condittons RD group (vasospastics)
Control group
stress
3.5 (0.92)”
3.1 (0.98)
Cold stress
1.4 (0.73)
1.2 (0.8 I )
~_.
~.
Cold + mental
‘Standard
deviation
Mental stress and Raynaud’s disease
475
and cold-only conditions separately for each group showed a significant difference only in the Control group [t(8) = 3.96, P < 0.011 but not in the RD group [t(8) < 1, NS]. Mean subjectives ratings of stress experienced by the two groups during exposure to the two types of stress are seen in Table 1. The subjective ratings were evaluated in a 2 x 2 (groups x conditions) split-plot factorial analysis of variance. Table 1 shows that the ratings during the cold + mental-stress condition are about three times as large as during the cold-only condition, with no differences between the groups. This impression was statistically supported by the significant main effect of type of stress [F(1,16) = 62.17, MS, = 0.84, P < O.OOl]. DISCUSSION The present study has shown increased peripheral vasoconstriction as mediated by lowered finger temperature to significantly occur only in the Control group, during a 15 min session when confronted with a mentally stressing task in a cold environment. the follow-up of the significant three-way interaction of minutes x Furthermore, conditions x groups suggested that time and stress seems to affect finger temperature more over time in nonvasospastics than in vasospastic individuals. If pulse-rate data are also included, the picture essentially shows a statistically reliable increase in pulse rate only in the Control group when mental stress is added, since no significant difference was observed between conditions in the RD group. Looking at the subjective ratings of stress in Table 1, it is obvious that there were no differences between the groups in experienced mental stress. Both groups showed increased ratings during the cold -t mental-stress condition. Thus, there is no reason to believe that the groups differed in subjectively experienced arousal as a function of the counting task. As such the present data do not wholly replicate previous case studies (Mittelmann and Wolff, 1939; Freedman et al., 1982) suffering from RD, where subjective rehearsal of emotionally stressful events has been shown to produce finger-temperature changes. Instead, the present results suggest that such a pattern of response is observed only in a group of nonvasospastic individuals when confronted with the same kind of cognitively demanding tasks. In fact, Fig. 1 reveals that the largest drop across time in finger temperature is shown by the Control Ss in the mental-stress condition when initial differences are corrected for. Thus, it cannot be concluded that a lowered finger temperature in a mentally stressful environment is an idiosyncratic characteristic of RD, since a greater response was seen in the nonvasospastic controls. The hypothesis of emotionality as a mediating mechanism in RD is therefore not supported by the present findings. An interesting finding in the present study is the apparently different cardiac pattern shown by the two groups in the cold + mental-stress condition. Acknowledging that the groups did not differ in subjectively experienced mental stress, it may be interesting to note that the higher subjective ratings in this condition were accompanied by a significant increase in pulse rate only in the Control group. Following the work of Obrist (e.g. Obrist, Howard, Lawler, Galosy, Meyers and Gaebelein, 1974) that an increase in heart rate during an avoidance situation (like fast counting to avoid shock) may be expected during efforts to actively cope with the situation, it should be noted that this pattern is absent in the RD group. In conclusion then, the present results have shown that both individuals suffering from vasospasms and normal controls respond with vasoconstriction in the fingers when mentally stressed in a cold environment. The Control Ss however showed larger changes in finger temperature over time in the mental-stress ‘condition than did the RD Ss. Although both groups showed equal increases in subjective ratings of stress in the cold + mental-stress condition, only the Control group also exhibited an increased pulse rate during this task. It is at present unclear why the RD group was inferior to the Controls in response of finger temperature to mental stress. One alternative is that the stress of anticipating and experiencing cold was much greater for the RD Ss compared to the Controls. A second possibility is that the differences between the groups are due to a more effortful performance of the task in the Control group, which affected the autonomic measures. This last possibility can not be ruled out on the basis of the present data, and may serve as an impetus for future research. This may have produced the seven degrees lower initial temperature for RD Ss compared with the controls in the cold + mental-stress, condition. We may thus have encountered a ‘floor effect’ where a further decrement in temperature cannot be regarded as physiologically equivalent.
476 Acknowledgement-This Humanities and Social
KENNETH HUGDAHL er al.
research was supported by a grant Sciences to Kenneth Hugdahl.
(Dnr
151182) from the Swedish
Council
for Research
in the
REFERENCES Bollinger A. and Schlumpf M. (1976) Fingerblood flow in healthy subjects of different age and sex and in patients with primary Raynaud’s disease. Acta chir. stand. (Suppl.) 465, 42-47. Coffman J. D. (1971) Diseases of the peripheral vessels. In Textbook OJ Medicine (Edited by Beeson P. and McDermott W.). Saunders, Philadelphia, Penn. Fagerstrom K.-O. and Melin B. (1982) A placebo controlled behavioral treatment of peripheral vasospasms with a one year follow up. Unpublished manuscript. Freedman R. R., Lynn S. J. and Ianni P. (1982) Behavioral assessment of Raynaud’s disease. In Assessment Srrategies in Behauioral Medicine (Edited by Keefe F. J. and Blumenthal J. A.). Grune & Stratton. New York. Graham D. T. (1955) Cutaneous vascular reaction in Raynaud’s disease in states of hostility. anxiety and depression. Psychosom. Med. 17, 201. Guyton A. C. (1976) Textbook of Medical Physiology. Saunders, Philadelphia, Penn. Holling H. E. (1972) Peripheral Vascular Diseases: Diagnosis and Manugemenr. Lippincott, Philadelphia. Penn. Kirk R. E. (1968) Experimental Design: Procedures for the Behavioral Sciences. Brooks/Cole, Belmont, Calif. Lang P. J. (1979) Emotional imagery and visceral control. In Clinical Applications of Biofeedback (Edited by Gatchel .. _ R. J. and Price K. P.). Pergamon Press, New York. Mendowitz M. and Naftchi N. (1959) The dieital circulation in Ravnaud’s disease. Am. J. Cardiol. 4. 580-584 Mittelmann B. and Wolff H. G. (i939)‘Affective states and skin temperature: experimental study of subjects with cold hands and Raynaud’s syndrome. Psychosom. Med. 1, 271-292. Nielsen S. I., Sorensen C. J. and Olsen N. (1980) Thermostated measurement of systolic blood pressure on cooled fingers. &and. J. c/in. Lab. Invest. 40, 683-687. Obrist P. A., Howard J. L., Lawler J. E., Galosy R. A., Meyers K. A. and Gaebelein C. J. (1974) The cardiac somatic interaction. In Cardiovascular Psychophysiology (Edited by Obrist P. A.. Black A. H.. Brener J. and DiCara L. V.). Aldine, Chicago, Ill. Raynaud M. (1862) De 1’Asphyxie Locale et de la Gang&e Symktique des Extr6mifiCs. Rigoux. Paris. Sedlacek K. (1979) Biofeedback for Ravnaud’s disease. Psvchosomutics 20. 535-541. Surwit R. S. (1982) Behavioral treatment of Raynaud’s syndrome in peripheral vascular disease. J. con&f. clin. Psychol. SO, 922-933. Surwit R. S., Williams R. B. Jr and Shapiro D. (1982) Behavioral Approaches to Cardiocascular Disease. Academic Press, New York. Thulesius O., Brubakk A. and Berlin E. (1981) Response of digital blood pressure to cold provocation in cases with Raynaud’s phenomenon. Angiologi 32, I 13-I 18.