AN EVALUATION OF FOREARM BLOOD FLOW AS A PSYCHOPHYSIOLOGICAL MEASURE

The usefulness of forearm blood flow (FBF) as a psychophysiological measure was investigated by comparing changes occurring during mental tasks in cardiovascular, sudomotor, and electromyographic measures. The measures were divided into those clearly physiologically independent and those physiologically related. ANOVA results showed that FBF, heart rate (HR), and skin conductance fluctuations (SCF) were equally reactive, and correlational analysis suggested that a close relationship existed between FBF, HR, and SCF, although correlations fell to near zero levels when intra-individual correlations were calculated with between task variance extracted. For some experimental purposes HR response may be considered equivalent to FBF response. The relationship between EMG and FBF was more variable, and tends not to support the idea that FBF is an indirect measure of muscle activity. The reliability of FBF in normal subjects at rest was poor, although it improved when measured during a simple task, and is probably stable enough for most experimental purposes.     

DEEP INSPIRATIONS AS STIMULI FOR RESPONSES OF THE AUTONOMIC NERVOUS SYSTEM

The effects of four types of deep breaths on the latency, the magnitude and the duration of finger volume pulse, heart rate and galvanic skin responses were studied in a quasi-learning situation. The respiratory stimuli were normal inspirations, three times deeper than normal, six times deeper and fast, and six times deeper and slow. Twenty Ss took each type of deep breath in random order six times in response to specific lights. Graphs and statistical tests are presented summarizing the above relationships and two unexpected findings are discussed.     

Cardiovascular and Electrodermal Responses Conditioned to Fear-Relevant Stimuli

This study examined heart rate, finger pulse volume, and skin conductance responses in subjects conditioned to fear-relevant (snakes and spiders) and fear-irrelevant (flowers and mushrooms) slide stimuli by an electric shock unconditioned stimulus. A differential conditioning paradigm with an interstimulus interval of 8 sec was used. There were 4 habituation, 8 acquisition, and 20 extinction trials with each of the two cues. The results demonstrated reliable acquisition for finger pulse volume and skin conductance responses, with superior resistance to extinction for the fear-relevant conditioned stimuli. The heart rate data showed no differentiation between reinforced and nonreinforced cues during acquisition and extinction, and no effect of fear-relevance. This discrepancy between skin conductance and finger pulse volume responses, on the one hand, and heart rate, on the other, was interpreted as due to differences in innervation, with the former measures mainly reflecting sympathetic and the latter parasympathetic effects.     

General Autonomic Components of Motion Sickness

This report refers to a body of investigations directed toward the examination of autonomic nervous system responses to motion sickness. Heart rate, respiration rate, finger pulse volume, and basal skin resistance were measured on 127 men and women before, during, and after exposure to a nauseogenic rotating chair test. Significant changes in all autonomic responses were observed across the tests (p<.05). Significant differences in autonomic responses among groups divided according to motion sickness susceptibility were also observed (p<.05). Results suggest that the examination of autonomic responses as an objective indicator of motion sickness malaise is warranted and may contribute to the overall understanding of the syndrome.     

PSYCHOPHYSIOLOGICAL AND LEARNING CORRELATES OF ANXIETY AND INDUCED MUSCLE RELAXATION

Recently, extensive use has been made of voluntary muscle relaxation as a response which presumably inhibits anxiety in “systematic desensitization” psychotherapies. This study attempted to test the hypothesis that muscle relaxation would reciprocally inhibit anxiety during a paired-associate learning task. Subjects (Ss) were divided into high, medium, and low anxiety levels and muscle tension, muscle relaxation, and normal tension groups. Paired-associate learning efficiency, as well as heart rate, skin conductance, integrated electromyogram, respiration rate, and finger temperature during learning were measured. Partial substantiation for the hypothesis was obtained for high anxiety Ss, but data for other groups was inconsistent with the hypothesis. An alternative explanation was suggested. Heart rate was the physiological variable which best discriminated the groups.     

HEART RATE CONDITIONING IN THE CAT AND ITS RELATIONSHIP TO OTHER PHYSIOLOGICAL RESPONSES

Twenty cats were classically conditioned using electric shock as the unconditional stimulus (US). A 1000 cps tone served as the reinforced conditional stimulus (CS+) and a 500 cps tone as the non-reinforced conditional stimulus (CS–). The CS–US interval was 10 seconds. Data collected show a heart rate deceleration to the CS+ which is accompanied by a drop in blood pressure, respiratory apnea, a negative baseline shift of the galvanic skin potential (GSP), pupillary dilatation, a decrease of the electromyographic (EMG) activity of the muscles of the shocked foreleg, and a low voltage fast pattern of the electroencephalographic (EEG) activity of the sigmoid gyrus of the cerebral cortex and olfactory bulb. The heart rate deceleration is present after muscle paralysis with succinyl choline and it is blocked by atropine. It is presumed to be of vagal origin. Difference in CS+ and US responsivity is discussed.     

Physiological Response Patterns to Cognitive Testing in Adults With Closed Head Injuries

Physiological measures were taken from 7 closed-head-injured patients and 7 control subjects while they took a series of cognitive tests: the finger tapping test from the Halstead Reitan battery, the Digit Symbol test from the WAIS-R, a test of logical memory, and a paced arithmetic test. Physiological reactivity was assessed relative to rest periods, which occurred at the beginning and end of each session. The tests and physiological assessment were administered twice, approximately one month apart. The patient group performed more poorly on the cognitive tests, and showed less physiological reactivity during them than did the control group. This pattern was statistically significant for heart rate, frequency of electrodermal responses, and, during the initial session, respiration rate. The control group also showed greater finger pulse amplitude during the first posttest rest period in the first session, and greater constriction during a logical memory task in the second session. No significant between-groups differences emerged for state or trait anxiety. The patients showed higher frontalis EMG and respiration rate during rest. These results suggest a pattern of poor physiological modulation for task performance in the patients with closed head injuries. The therapeutic implications are discussed.     

Orienting in Schizophrenia: Habituation to Auditory Stimuli of Constant and Varying Intensity in Patients High and Low in Skin Conductance Responsivity

Groups of schizophrenics and normal controls were exposed to different series of tones of constant (80dB) and variable intensity (60, 80, and 100 dB). Measurements included bilateral skin conductance, finger pulse volume, and heart rate. Both groups were split on the common median in skin conductance response to constant intensity tones to form matched patient and control groups of low and high responsivity. The low and high responsive schizophrenic groups were more clearly separated than the two control groups in rate of spontaneous skin conductance fluctuations, skin conductance magnitudes, and skin conductance levels, primarily because of generalized hyperactivity in high responsive patients. This pattern was clearest for the most intense tone and left hand recordings. High responsive schizophrenics also showed larger response amplitudes, shorter rise and recovery times, and a smaller ratio of elicited to spontaneous responses, than high responsive controls. Finger pulse volume responses recorded from the left hand were smaller in the patient groups, whereas patients and controls did not differ in right hand recordings. High skin conductance responsive subjects showed more heart rate deceleration than low responsive subjects, and schizophrenics had more decelerative responses than controls.     

Autonomic and Affective Reactions of High and Low Socially-Anxious Individuals Awaiting Public Performance

The physical threat anticipation paradigm was modified for the study of anticipatory social anxiety responses. It was found that heart rate (HR) and skin conductance (SC) responses during anticipation of a socially threatening event (i.e., public speaking) were similar to those occurring prior to physical threat, with the largest changes taking place during the final portion of anticipation. Likewise, self-reports of cognitively experienced nervousness displayed a positively accelerating pattern of increase as the time of performance approached. The present findings suggest a psychological time-division process, such that the anticipation interval consists of an initial waiting period, followed by a briefer period of active preparatron. During the anticipation interval high and low socially-anxious subjects displayed similar HR and SC responses, but differed significantly in patterns of finger pulse volume (FPV) and self-reported nervousness. As performance became imminent, high socially-anxious subjects evidenced increased vasoconstriction and reported greater nervousness than low socially-anxious subjects. Taken together, these results indicate that, irrespective of psychometrically assessed anxiety, and/or type of threatening stimulus, the autonomic patterns during anticipation of threat are characterized by accelerating responsiveness. Thus, the temporal parameter of the anticipation situation (i.e., remaining time) is the primary determinant of reactions while awaiting threat.     

ACTIVATION STATES AS ASSESSED BY VERBAL REPORT AND FOUR PSYCHOPHYSIOLOGICAL VARIABLES

The present research was part of a program aimed at examination of the validity of controlled verbal reports of various activation states. A difference score design was used in which four psychophysiological measures and verbal ratings of various activation states were obtained in a baseline and an activation period from 41 female subjects. Verbal reports were then correlated with individual physiological measures and composites or indices of physiological measures. Specifically, two kinds of physiological index were employed, one in which the subject's physiological change score was represented by the single system showing the greatest change, and a second index weighted equally by all four physiological measures. The physiological index using the single system showing the greatest activation yielded slightly greater correlations with verbal report than the other index. Skin conductance and heart rate, the best combination of the four physiological systems measured, correlated as high as .62 with verbal report. The results were interpreted as demonstrating the usefulness and validity of controlled self report and the relative superiority of skin conductance and heart rate among other physiological systems in correlations with verbal report.     

Cardiovascular and Electrodermal Response Patterns in Heart Rate Reactive Individuals During Psychological Stress

The goal of this research was to examine the cardiovascular and electrodermal response patterns of heart rate reactive and nonreactive individuals to psychological stress. Sixty males were tested while resting, listening to tones, identifying tone patterns, and performing mental arithmetic. Dependent variables were blood pressure, heart rate (HR), and skin conductance responses. Based on the change in HR from baseline to the first minute of mental arithmetic, two extreme reactivity groups of 15 subjects each were formed. Results indicated that HR reactive subjects had higher systolic blood pressure and HR than nonreactives. Reactives showed greater HR lability during all the tasks and a phasic acceleration to tones, while nonreactives showed a deceleration. Finally, comparisons of skin conductance responses indicated that subjects who were nonreactive when measuring HR were more reactive when measuring skin conductance. The HR reactivity seen in these subjects has been linked to predisposition to psychosomatic illness, and the current findings are discussed in that light.     

CHANGES IN ELECTROENCEPHALOGRAM AND OTHER PHYSIOLOGICAL MEASURES DURING SERIAL MENTAL PEREORMANCE

This study attempted to answer two questions: (1) Can electroencephalogram (EEG) amplitude changes be related to specific moment-to-moment changes in task performance? (2) To what extent are EEG changes related to changes in other indices of activation? Physiological responses were recorded from 20 subjects during 12 alternately fast and slow trials of a paced auditory serial addition task and three writing trials involving similar responses. Trial-by-trial results showed that EEG amplitude usually tended to covary with other physiological functions in a manner expected from activation theory. All physiological levels decreased during the session but became increasingly sensitive to differences in task difficulty. Within trials there was some concordance between alpha amplitude levels and other physiological levels, but exceptions to this trend and further analysis of palmar conductance patterns suggested that consideration of differential sensitivities of the individual measures to behavioral events might be more profitable than an activation theory approach. The only relation between EEG changes and specific behavioral events was the tendency for alpha and beta to block during motor responses.     

Psychophysiological responses to auditory change

A comprehensive characterization of autonomic and somatic responding within the auditory domain is currently lacking. We studied whether simple types of auditory change that occur frequently during music listening could elicit measurable changes in heart rate, skin conductance, respiration rate, and facial motor activity. Participants heard a rhythmically isochronous sequence consisting of a repeated standard tone, followed by a repeated target tone that changed in pitch, timbre, duration, intensity, or tempo, or that deviated momentarily from rhythmic isochrony. Changes in all parameters produced increases in heart rate. Skin conductance response magnitude was affected by changes in timbre, intensity, and tempo. Respiratory rate was sensitive to deviations from isochrony. Our findings suggest that music researchers interpreting physiological responses as emotional indices should consider acoustic factors that may influence physiology in the absence of induced emotions.     

Assessment of phasic work stress using autonomic indices

The present paper concerns the assessment of phasic work stress using autonomic indices such as skin temperature, respiratory measures, and heart rate, blood pressure, and their variabilities. A physiological model of the autonomic regulation of the cardiovascular and respiratory systems is also introduced in order to simulate and interpret the changes in these indices. Two experiments were conducted to investigate high tension and monotony as two types of mental work stress. A tracking task was used to induce high-tension work stress with and without an instruction intended to induce additional emotional stress. The same tracking task was repeated 12 times to simulate monotonous work stress. Fifty healthy adults participated in each experiment. Many physiological measures showed task-dependent changes in the high-tension experiment and at the beginning of the monotonous stress condition. These changes were explained by sympathetic activation, parasympathetic withdrawal, and respiratory rate activation. An additional drop in skin temperature and an additional HR increase were caused by the stressful instruction, which may reflect an emotional strain and can be explained by sympathetic activation. Furthermore, the mid-frequency component (approx. 0.1 Hz) of respiration and respiratory instability showed an obvious increase during the course of the monotonous stress experiment, which may reflect boredom and disgust. It was concluded that multidimensional recordings of autonomic measures that can be obtained during work without extra load on the worker would be helpful to assess different types of phasic work stress. The proposed model was further shown to be able to detect periods of stress in a complex work environment.     

Influence of temperature on the distribution of blood in humans as assessed by electrical impedance

This study investigated whether ambient temperature influences the distribution of blood as indicated by electrical impedance. In ten supine humans, the room temperature was raised from 14 to 35°C. Skin temperature and blood flow on the thorax increased by 3.6 (SD 0.3)°C and 84 (SD 40)%, respectively, and by 9.8 (SD 1)°C and 115 (SD 45)%, respectively, on the extremities (P < 0.05). Cardiac output remained unchanged, ear temperature and heart rate became elevated, and the oesophageal temperature and mean arterial pressure decreased (P < 0.05). At five discrete frequencies (1.5, 5, 50, 100, 200 kHz) thoracic impedance was increased by 1.2 (SD 1) to 1.5 (SD 1) Ω (P < 0.05). In contrast, total body impedance was reduced by 16.4 (SD 5) Ω and leg impedance was reduced by 4.0 (SD 2) Ω, while an index of intracellular water within the thorax (the difference between the admittances at 100 kHz and 1.5 kHz) was decreased by 10 (SD 1) · 10⁻⁴ S (P < 0.05). The results would suggest that total body impedance is dominated by the impedance of the extremities. The increase in thoracic impedance and a decrease in leg impedance (as in total body impedance) could be explained by a redistribution of blood from the thorax to the extremities during heating. Such a translocation of blood was confirmed by a reduced impedance based index of intracellular water within the thorax. Accepted: 4 June 1999     

EFFECTS OF DEPTH AND RATE OF BREATHING ON HEART RATE AND HEART RATE VARIABILITY

Effects of depth and rate of breathing on heart rate (HR) and HR variability were observed in two experiments. Respiration rate (RR) affected only cardiac stability, faster breathing producing more stable cardiac rate. Respiration depth (RD) affected both HR level and variability. Deep breathing produced faster, more variable HR, while shallow breathing had the opposite effects. A third experiment, in which Ss were trained to control HR using respiration, further illustrated the dramatic effects of respiration on cardiac rate. Implications of these results for experiments utilizing HR as a dependent variable and studies of autonomic control were discussed.     

THE EFFECTS OF VARIED RESPIRATORY RATE AND VOLUME UPON FINGER PULSE VOLUME

The effects of varied conditions of respiratory rate and volume upon finger pulse volume were investigated. Results indicated that any change in ongoing respiratory activity resulted in maximal digital vasoconstriction within 4–6 sec, and that these effects were greatest during deep breathing. The relevance of these findings for investigations of vasomotor conditioning are discussed.     

二种钙拮抗剂对冠心病患者心率变异性的影响

观察了50例冠心病患者分别服用合心爽(60mg,tid,一周),和拜心通(30mg,Bid,一周)后心率变异性(HRV)的变化。结果:冠心病患者24h HRV频域指标中的总功率谱面积(TP)、高频成份的标准化单位(HFn)及低频成份标准化单位(LFn)的各时段测值与健康对照组比较有显著差异;服用合心爽后,TP、HFn、LFn的各时段测值均较用药前显著改善,服用拜心通后则无相应改善。提示合心爽能显著改善冠心病患者的心脏自主神经功能异常,拜心通无明显影响。