Changes In Skin Conductance Level Research Articles

EMG biofeedback treatment of torticollis: A controlled outcome study

Successful treatment of torticollis with electromyographic (EMG) biofeedback has been reported in a number of single case and single group studies. The present investigation represents the first controlled outcome study. Twelve torticollis patients were randomly assigned to EMG biofeedback or relaxation training and graded neck exercises (RGP). The procedure involved three sessions of baseline assessment, 15 sessions of EMG BF or RGP, 6 sessions of EMG BF or RGP plus home-management, 6 sessions of home-management alone, and follow-up 3 months after the end of treatment. A variety of outcome measures were used including physiological (EMG from the two sternocleidomastoid muscles, skin conductance level), behavioral (angle of head deviation, range of movement of the head), and self-report (depression, functional disability, body concept), therapist and "significant other" reports and independent observer assessment of videos. In both groups, neck muscle activity was reduced from pre- to posttreatment. This reduction was greater in the EMG biofeedback group. There was evidence of feedback-specific neck muscle relaxation in the EMG biofeedback group. Therefore, the outcome was not due to nonspecific factors and could be attributed to feedback-specific effects. Changes in skin conductance level showed that neck muscle relaxation was not simply mediated by a general reduction of "arousal." Significant improvements of extent of head deviation, and range of movement of the head, as well as reductions of depression were present, which were not different in the two groups. At the end of treatment, no patient was asymptomatic. Any therapeutic benefit was generally maintained at follow-up. The results and the procedural simplicity of RGP make the issue of cost-efficacy of EMG biofeedback a pertinent one. Further controlled outcome studies of EMG biofeedback treatment of torticollis with larger samples are required.

Effects of fear-relevance on electrodermal safety signal learning

Safety signal learning in human subjects was investigated using a conditioned inhibition procedure with a shock unconditioned stimulus (US). The conditioned stimulus (CS) duration, and thus the CS-US interval, varied randomly from 20 to 50 s. Conditioning was assessed by change in tonic skin conductance level (SCL). Experiment 1 demonstrated reliable learning of a conditioned inhibition (A + /AB −) discrimination, in terms of both self-reported shock expectancy and change in SCL, in subjects who were able to report correctly the stimulus contingency. There was, however, no evidence of transfer of inhibitory properties from the safety signal B to a separately trained excitor. Experiment 2 compared two groups in which the safety signal was either fear-relevant (picture of snake or spider) or fear-irrelevant (flower or mushroom). As in previous research, there was no effect of fear-relevance on safety-signal learning. The results are discussed in terms of preparedness theory and excitatory conditioning with fear-relevant stimuli.

Human urinary biogenic amines and some physiological responses during situation stress

Using a shooting competition as a model, the effect of situation stress on self-assessed mental tension, urinary metanephrine, normetanephrine, 3-methoxy-4-hydroxymandelic acid, 4-hydroxy-3-methoxyphenyl acetic acid and 5-hydroxyindole acetic acid (5-HIAA), as well as heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), skin conductance level (SCL) and electromyographic (EMG) parameters were studied in 7 male and 2 female champion rifle and (rapid-fire and air-)pistol shooters. The sample collection and recordings were carried out first in the training (baseline) circumstances and then during the competition. Self-assessed mental tension was higher than suitable during the competition but good performance was the expectation. During the competition, HR, SBP, DBP, SCL and EMG were increased significantly as compared with the baseline levels. No significant correlations between the variables and between the biogenic amine metabolite excretions were observed. The competition-induced changes in self-assessed mental tension correlated positively with the corresponding changes in SCL ( r=0.63), but negatively with changes in SBP ( r=-0.74). The HR of male rapid-fire pistol shooters was higher than that of male rifle shooters ( P < 0.05). All the urinary biogenic amine metabolite excretion levels were increased significantly as compared with the baseline values. Higher metabolite excretion was observed in rifle shooters than in rapid-fire shooters ( P<0.05). The correlation between catecholamine metabolites was significant ( r=0.67−0.93), but surprisingly the correlation between 5-HIAA and catecholamine metabolites was highly significant ( r=0.80−0.91). This study indicates a marked divergence in the behaviour of various stress-responsive variables during shooting competitions. The stress during competition seems to activate mental tension above a suitable level without any signs of overstimulation.

Augmenting-reducing of the visual evoked potential as a function of changes in skin conductance level.

ABSTRACTIn the first of two experiments four visual evoked potential (VEP) measures of augmenting‐reducing were made consecutively within a single test session on each of 10 student volunteers, on whom palmar skin conductance, taken as an index of arousal, was also monitored continuously. Regression slopes relating VEP amplitude to stimulus intensity for any given individual were found to vary considerably over the session, some subjects changing from augmenting to reducing (or vice versa) during testing. Further analysis of the within‐subject data indicated that shifts in augmenting‐reducing were related to changes in skin conductance level (SCL) and to the range of SCL over which individuals were operating in relation to the group. Thus, subjects in the high SCL range shifted toward relative reducing as their conductance level increased and those in the low SCL range toward relative augmenting. These effects were exactly replicated in a second experiment using a further 10 subjects and a virtually identical procedure. It was concluded that augmenting‐reducing is partly state‐dependent, though in a manner which is systematic enough to warrant its further investigation in studies focusing on the dynamic aspects of stimulus modulation.

Effects on behavioral responding on skin conductance level.

The effects of behavioral response requirements on skin conductance level (SCL) were studied. Initial Ss were placed in either a “non-respond” (NR) or a “respond” (R) condition. No clear effects were observed other than large differences in individual response to both conditions. Subsequent use of a within- Ss replication design showed, however, that behavioral requirements have a tonic effect on SCL and that anticipatory changes in SCL may occur prior to the R condition. The results support the hypothesis that autonomic and behavioral events are essentially integrated and, in addition, suggest the efficacy of the within- Ss replication design in treating individual differences.