Neck massage effects on skin conductance in healthy subjects

The purpose of this study was to investigate the direct effects of neck massage using a psychophysiological index, and more specifically, skin conductance. Therapeutic massage is a technique used in everyday life for dealing with many health problems. During the past years a great effort has been under way to establish objective results that will affirm its proven clinical effectiveness. Skin conductance is the most commonly used psychophysiological index showing the activation of the autonomic nervous system. Its simple recording, simple waveform and skin application make this index quite appealing for psychophysiological studies.

Nineteen health female subjects aged 20-30 years old (22.9 2.7) participated in this study as the experimental population. Thus, an effort was made to eliminate effects of sex and age. Under well-defined conditions, the subjects undertook simple neck massage (effleurages), while lying on their back for ten minutes. The massage was carried out by the same therapist for all subjects and an effort was made to keep the therapeutic relationship neutral. During the massage session, skin conductance levels on the fingers of the hand were recorded. Electrodes were adjusted on the fingers of each subject (index and ring fingers) to record skin conductance response. 12,000 recorded values that correspond to the total intervention period (10 minutes) were analyzed. Same data were also assessed per five two-minute intervals to show any behavioral change in smaller intervals. To this end, a one-way ANOVA and post-hoc Bonferroni test was performed on each subject separately. Statistically significant differences were found (one way ANOVA, p<0.01) between the averages of the five two-minute intervals, and the direction of the differences was demonstrated by applying the Bonferroni test. The classification of subjects into three groups was made possible by statistical elaboration of data collected. The first group was comprised of the vast majority of subjects (12 out of 19). The second, much smaller, group was comprised of 4 out of 19. The third group comprised of the last 3 subjects. Skin conductance levels on the subjects of the first group (63,2% of the total) followed a constantly downward trend, skin conductance levels of the second group (21% of the total) were overall discontinuously reduced, while subjects of the third group (15.8% of the total) behaved in a way that would not allow their inclusion in the previous groups. Judging by temporal correlations, it appears that 17 out of 19 subjects (89.5% of the total) confirm that short-term massage on the neck has a direct influence on skin conductance levels and indeed tends to reduce its value.

Result analysis showed that the vast majority of subjects behaved in a way that has a direct correlation with the decline of the sympathetic nervous system activity, which is in turn directly linked to a feeling of general relaxation. Success of massaging methods on various health problems has been recorded. The significance of these results is far greater if one takes into account the importance of the reliability of the psychophysiological index of skin conductance used in this paper.

One of the important observations is that the results of neck massage bring about a general relaxation. These results reinforce supporting views that therapeutic massaging is a useful method to relieve many symptoms.

The objective control provided by the use of psychophysiological indexes is important to check the effectiveness of methods and techniques used in everyday medical care.

Key words: Massage, phychophysiological indexes, skin conductance, relaxation.