ABOUT THE MALADAPTIVE NATURE OF PALMAR SWEATING AND HYPERHIDROSIS

ABSTRACT
In this work, the influence of the benefit of palmar wetting in the intensity of palmar sweating was examined. The electrodermal activity (EDA) of hyperhidrotic and normal subjects was compared, in a leafing (palmar wetting is desirable) and fingerprinting (palmar wetting is unwanted) tasks. Hyperhidrotic, in the same degree as normal subjects, presented a higher EDA during leafing than fingerprinting. We concluded that the ability of a beneficial manifestation of palmar sweating does not be lost in the case of palmar hyperhidrosis. This finding may implies that It must be questioned the unsophisticated view for the maladaptive nature of palmar hyperhidrosis or the neurotic manifestation of a function in general.
INTRODUCTION
Many times a day, the electrodermal activity (EDA) of a subject seems to be pointless, since there is no benefit of palmar wetting (friction improvement or abrasion prevention Adelman et al. 1975, Wilcott 1966) for the subject's action. These times, the manifestation of palmar sweating offers no adaptation to the action demands, probably it complicates that, and could be considered maladaptive. Fowles' (1986) question of whether this function is simply a complex and noisy manifestation of non-specific activity is absolutelly justifiable from this side of view.
The isolation of palmar sweating from the action's demands of palmar wetting can be understandable if palmar and plantar sweating, as a residue of the evolution, follows mass sympathetic discharge, at fight and flight reactions (Cannon's theory) and there is no kind of a special regulation for this. However, the following findings, coming from different fields of the research, challenge this view: (i) the sympathetic nervous system has been approved that has a greater capacity for specificity than has usually been attributed to it (Lacey 1967, Miller 1969a, Miller 1969b), (ii) autonomic manifestations differ considerably among anxiety disorders (Saric and McLeod 1988, Ost et al. 1984), e.g. depressed patients exhibit higher tonic heart rate levels in parallel with lower tonic skin conductance levels (Dawson 1985), (iii) EDA was eliminated during the REM phase of sleep, in contrast to all other sympathetic functions which remained at the same levels as in awakening (Johnson and Lubin 1966, Lester et al. 1967, Kushniruk et al. 1985), (iv) intraneural recordings of sympathetic nerve traffic have shown that the view of a diffusely acting system led to the term "sympathetic tone" is not tenable (Wallin 1992, Wallin and Elam 1994), (v) we have found from recordings during sexual intercourse and orgasm that palmar sweating is not augmented in the moment of orgasm when a mass sympathetic activation takes place. These findings led us to the conclusion that palmar sweating is not manifested as an indistinct concomitant of sympathetic discharge.
In order to exlore the way of the palmar sweating regulation, we had posed the question of how far the intensity of palmar sweating is influenced by the usefulness of palmar wetting in action. In an experiment special designed to give an answer to this quuestion, we found that palmar sweating was significantly higher in leafing (palmar wetting was desirable) than weighing a hydrophilic substance (palmar wetting was unwanted), although both tasks designed to involve, within the bounds of possibility, the same movement's demands and emotional load. Normal palmar sweating subjects were participated to this experiment. This finding was an indication that the usefulness of palmar wetting influence the intensity of palmar sweating, an indication that probably a cognitive appreciatory mechanism contributes to the regulation of palmar sweating in a purposeful way.
After that the problem could be placed in new terms: what happens to this appreciatory mechanism when excessive palmar sweating takes place and no benefit of palmar wetting in action can be found (examinations, social relationships, writing, etc.)? The most clear-cut case of pointless palmar sweating is observed in the palmar hypehidrosis. We posed the question of whether a disruption of the appreciatory of the benefit of palmar wetting mechanism take place in palmar hyperhidrosis.
The answer to this question may be of greater interest for the neurotic manifestation of a function in general. Neurotic manifestation of a function is predominately considered maladaptive (Eysenck 1979) and we have collected the following findings which support the hypothesis that palmar hyperhidrosis is indeed a neurotic manifestation of palmar sweating: (i) palmar hyperhidrosis is not controlled by a thermoregulatory mechanism (Kerassidis 1994), (ii) clinical and laboratory test, general haematological, levels of thyroid hormones, glucose and electrolytes, heart rate variability (performed after 24 hours electrocardiogram recording as an estimate of autonomic balance), neurological examinations, estimation of the density of sweat glands on palms of hyperhidrotics, etc. failed to reveal any type of organic disease as an antecedent of palmar hyperhidrosis (papers submitted for publication). (iii) hyperhidrosis is expressed in discomfort and some individuals had manifested hyperhidrosis for a trancient hard period of their life, which was dissapeared when the problems were overcame (from interviews with hyperhidrotic in palms subjects, attracted by local mass media for the research) (iv) personality's tests (Eysenck's Personality Questionnaire and Minnesota Multiphasic Personality Inventory) revealed significant differences between hyperhidrotic and normal subjects in neuroticism traits. We have concluded that the neuroticism probably makes hyperhidrotics more prone to identify stressors as discomfort producing.
MATERIALS AND METHODS
Subjects
Twenty: 10 hyperhidrotic in palms, mean age 33 years old (range 18-56) and 10 normal palmar sweating subjects, mean age 30 years old (range 20-62), participated in this experiment. Males were 5 and females also 5, in each group.
Materials
J&J Modules of Unicomp was used for the recording of conductivity of right palm. The electrodes were of Ag-AgCl. Day books were used for leafing. An ink-pad and sheets were used for fingerprints.
Procedure
Subjects read instructions for leafing. They were reminded that leafing would be facilitated if their forefinger could sweat. They made a leafing rehearsal in order to familiarise with the procedure. So their electrodermal responses (EDRs) during leafing would not be part of startling or novelty reaction. They had to turn the pages of a day book only by the forefinger and stay still the fingers with electrodes (thumb and middle finger), in order to avoid artifacts, for 100 seconds. No conversation was permitted.
After leafing, electrodes were not removed, in order to prevent artificial changes to the level of conductivity (LC). Subjects read the instructions to make continuously fingerprints of the fingers of both palms. They were reminded that they had to avoid palmar sweating for good quality fingerprints. They performed this task for 100 seconds too.
The order of execution of the tasks in this procedure was opposite of that of our previous experiment where only normal subjects participated. Now, the leafing (palmar wetting was desirable) was performed first and fingerprinting (palmar wetting is unwanted) followed. In the previous experiment the weighing of the hydrophilic substance was performed first (palmar wetting was unwanted) and leafing followed. We reversed the order of the execution of the tasks in order to check how the result of the previous experiment could be caused by some kind of sensitisation. We changed the weighing of the hydrophilic substance with the fingerprinting in order to make more similar the tasks, since in both leafing and fingerprinting the fingers tuch paper (if a somatosensory feedback would be important).
RESULTS
We compared the number of electodermal responses (EDRs) and the mean skin conductance level (SCL) between leafing and fingerprinting. As EDR we accepted any increase in palmar conductivity over 0.3 μS and the mean SCL was calculated by the computer as the mean value of 20 mean values of SCL for 5 sec each one.
One tail paired t-test revealed that the number of EDRs of normal palmar sweating subjects was significantly higher (P<.002) during leafing than fingerprinting. Hyperhidrotics, similarly, had significantly higher (P<.002) EDRs during leafing than fingerprinting. In both groups the number of EDRs during fingerprinting was diminished about in the half of those during leafing. A two factor (sex, hyperhidrosis) analysis of variance (ANOVA) on the number of EDRs during leafing and fingerprinting did not reveal any significant difference, although hyperhidrotics had, in both tasks, a higher number of EDRs than normal subjects.
One tail paired t-test revealed that the mean SCL of normal palmar sweating subjects was significantly higher (P<.003) during leafing than fingerprinting. Hyperhidrotics, similarly, had significantly higher (P<.005) mean SCL during leafing than fingerprinting. The diminution of mean SCL from leafing to fingerprinting was about 30% for both groups. A two factor (sex, hyperhidrosis) analysis of variance (ANOVA) on mean SCL during the two tasks revealed that hyperhidrotics had a significantly higher (P<.02) mean SCL during leafing than normal subjects, and a significantly higher (P<.01) mean SCL during fingerprinting. Females had a significantly higher (P<.05) mean SCL during both tasks and the interaction of the factors (sex, hyperhidrosis) was also significant (P<.05) in both tasks.
DISCUSSION
We found that both hyperhidrotic in palms and normal palmar sweating subjects expressed higher EDA during leafing (palmar sweating is desirable) than fingerprinting (palmar sweating is unwanted). The diminution of palmar sweating from the first to the second task was about the same for both hyperhidrotic and normal subjects. The mean palmar SCL of hyperhidrotics and females was higher than normal subjects and males respectively, in both tasks. The finding for normal subjects replicated the finding of our previous similar experiment and confirmed the suggestion that the magnitude of palmar sweating is influenced from the usefulness of palmar wetting in action. As far as the hyperhidrotics are concerned, it was expected that the influence of the palmar wetting usefulness to the magnitude of palmar sweating would be lesser than normal subjects or it would not exist at all. However, the fact that palmar sweating of hyperhidrotics is differentiated between tasks analogously to the benefit of palmar wetting, indicates that no disruption of the appreciatory of usefulness mechanism takes place, even in the case of excessive-neurotic manifestation of palmar sweating. This finding challenges the unsophisticated view about the maladaptive nature of excessive sweating and hyperhidrosis, perhaps and for the neurotic function in general.
But how can be explained that palmar sweating is manifested in examinations, social relationships, writing, etc. when no benefit of palmar wetting in action can be found? We faced this phenomenon in the second task when the palmar sweating of both groups was not zero, despite that it was absolutely undesirable. Two interpretations can be given. The first is that the impact of the appreciatory mechanism is limited and it is superimposed to the impact of other, more automatically influenced the palmar sweating factors. The second is that the benefit from palmar wetting is only one of the elements of the appreciatory mechanism in its regulation of palmar sweating. In order to judge these interpretations we have to remind that since a sound may in general cause an EDR to a subject, a weak noise in a danger environment may cause a strong EDR and no EDR may be caused by a loud noise in a disco. Obviously, there is a strong determination of the electrodermal behaviour by an appreciatory mechanism for a wide limited area of stimuli and conditions. Perhaps this is in other words the same with the tendency for electrodermal reflexes to involve control by the highest centers unless otherwise prevented (Venables 1991).
We suggest that a nonword appreciatory mechanism is still working in these cases when palmar sweating takes place and no benefit of palmar wetting in action can be found. However, the estimation of this mechanism may not only rely on how useful is the palmar wetting. Palmar sweating may be useful for other reasons to the organism beyond mechanical facilitation of the action. There is a large piece of evidence in the research of EDA which permits making a suggestion about that, but it must be in a review article.
REFERENCES
Adelman, S., Taylor, C. R. and Meglung, N. C. (1975) Sweating on paws and palms: what is its function? Am. J. Psychol., 229(5): 1400-1402.
Dawson, M. E.et al (1985) Diagnostic utility of autonomic measures for major depressive disorders. Psychiatry Res., 15: 261-270.
Eysenck, H. J. (1979) The conditioning model of neurosis. Behav. Brain Sci., 2: 155-199.
Fowles, D. C. 1986. The eccrine system and electrodermal activity. In: M. G. H. Coles, E. Donchin, S. W. Porges (Eds), Psychophysiology : Systems, Processes, and Applications., Elsevier, Amsterdam, pp. 51-96.
Hoehn-Saric, R. and McLeod, D. R. (1988) The peripheral sumpathetic nervous system. Its role in normal and pathological anxiety. Psychiatr. Clin. North Am., 11(2): 375-386.
Johnson, L. C. and Lubin, A. (1966) Spontaneous electrodermal activity during waking and sleeping. Psychophysiology., 3(1): 8-17.
Kerassidis, S. (1994) Is palmar and plantar sweating thermoregulatory? Acta Physiol. Scand., 152: 259-263.
Kushniruk, A., Rustenburg, J. and Ogilvie, R. (1985) Psychological correlates of electrodermal activity during REM sleep. Sleep., 8(2): 146-154.
Lacey, J. I. (1967) Somatic response patterning and stress: Some revisions of activation theory.In: M.H. Appley and R. Trumbull (Eds), Psychological Stress (Issues in research), Chapter 2, ACC, New York, pp. 15-42.
Lester, B. K., Burch, N. R. and Dossett, R. C. (1967) Nocturnal EEG-GSR profiles : the influence of presleep states. Psychophysiology, 3: 238-248.
Miller, N. E. (1969) Psychosomatic effects of specific types of training. Ann. N. Y. Acad. Sci., 159: 1025-1040.
Miller, N. E. (1969) Learning of visceral and glandural responses. Science. 163: 434-445.
Ost, L., Sterner, U., Lindahl, I. (1984) Physiological responses in blood phobics. Behav Res Ther. 22(2): 109-117.
Venables, P. H. (1991) Autonomic activity. Ann. N. Y. Acad. Sci., 620: 191-207.
Wallin, B. G.(1992) Intraneural recordings of normal and abnormal sympathetic activity in man. In: R. Bannister, C. J. Mathiaw (Eds), Autonomic Failure. A textbook of clinical disorders of the autonomic nervous system, Oxford Medical Publications, Oxford, pp. 359-377.
Wallin, B. G. and Elam, M. (1994) Insights from intraneural recordings of sympathetic nerve traffic in humans. Am. Physiol .Soc., 9: 203-207.
Wilcott, R. C. (1966) Adaptive value of arousal sweating and the epidermal mechanism related to skin potential and skin resistance. Psychophysiology, 2(3): 249-262.