Is the hyperhidrotic palmar sweating unrelated to the action demands on palmar wetting?

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 leafing (turning sheets by rubbing the finger, so palmar wetting was desirable) and fingerprinting (making ink prints of fingers on a paper sheet, so palmar wetting was unwanted) tasks. Hyperhidrotic, in the same degree as normal subjects, presented a higher EDA during leafing than fingerprinting, although both tasks designed to involve the same movement and emotional load. We concluded that the ability of a beneficial manifestation of palmar sweating is retained in the case of palmar hyperhidrosis. This finding, in addition to the further investigation on palmar hyperhidrosis, contributes also to the clarification of what the maladaptive nature of a neurotic function means.



DESCRIPTOR TERMS

Hyperhidrosis, palmar sweating, electrodermal, maladaptive, neurotic.


Is the hyperhidrotic palmar sweating unrelated to the action demands on
palmar wetting?

Stelios Kerassidis

INTRODUCTION
Trying to find out what is behind palmar hyperhidrosis we already know that: (i) it is not controlled by a thermoregulatory mechanism (Kerassidis 1994), (ii) extended clinical and laboratory tests, did not reveal any type of organic disease (Kerassidis et al. 1997), nor a higher density of sweat glands on palm of hyperhidrotics (kerassidis & Haristou 1997), (iii) hyperhidrotic presented higher score in Neuroticism scale of Eysenck's Personality Questionnaire (Kerassidis et al.) and in Psychasthenia, Social Introversion, and Depression of Minnesota Multiphasic Personality Inventory (kerassidis & Bitzaraki, 1996), (iv) in agreement with the suggestion of Lerer et al. (1980) and of Lerer and Jacobowitz (1981) that hyperhidrotic individuals are characterised by lower overall ability to cope with stress and a strong proclivity to avoid problems, we found that excessive palmar sweating is provoked by feelings of discomfort (no relaxed subjects) and we concluded that personality traits may make hyperhidrotics more prone to identify stressors as discomfort-producing (Kerassidis et al.).
The above findings leads to the conclusion that palmar hyperhidrosis may be a neurotic manifestation of normal palmar sweating, a disorder of the type of psychosomatic ones. Since neurotic manifestation of a function is predominately considered maladaptive (Eysenck 1979), we wondered how wrongly excessive palmar sweating is expressed. Many times a day, the electrodermal activity (EDA) of an individual, (not only of a hyperhidrotic one), seems to be pointless, since there is no benefit of palmar wetting (friction improvement Adelman et al. 1975, or abrasion prevention Wilcott 1966) in action. During examinations, social relationships, writing, etc., the manifestation of palmar sweating offers no adaptation to the action demands, it rather troubles them, and could be considered maladaptive. Fowles' (1986) questioned whether this function is simply a complex and noisy manifestation of non-specific activity.
To answer this question, we designed a series of special experiments and we found that palmar sweating of non-hyperhidrotic individuals, was significantly higher in leafing (turning sheets by rubbing the finger, so palmar wetting was desirable) than weighing a hydrophilic substance (palmar wetting was unwanted), although both tasks designed to involve the same demand of movement and emotional load (unpublished). This finding indicated that the usefulness of palmar wetting influence the intensity of palmar sweating, so in normal individuals, an appreciatory of the benefit of palmar sweating mechanism was seen to exists.
In the present work we try to give an answer to the question of how the palmar sweating is influenced by the usefulness of palmar wetting in the case of palmar hyperhidrosis, hoping that it could be useful to the discussion about the maladaptive nature of the condition.
We have to note that the old view of general arousal or general sympathetic arousal must not be considered as an answer to the question of the way the palmar hyperhidrosis is expressed. Namely, that it simply follows mass sympathetic discharge, at fight and flight reactions (Cannon's theory). Former and recent studies from different fields of research, have challenged the view of a diffusely acting sympathetic system (Lacey 1967, Miller 1969a, Miller 1969b, Wallin 1992, Wallin and Elam 1994). Besides, it is well known that autonomic manifestations differ considerably among psychological disorders (Saric and McLeod 1988, Ost et al. 1984, Dawson 1985), stimulus presentation, or condition of performance (Edelberg, Venables, Fowles), that means that no theory of general or sympathetic arousal can overcome the question why the specific function is triggered under specific conditions. Finally, we recorded a slight or not a bit palmar sweat glands activation during human orgasm (when a mass sympathetic activation was taking place), and we concluded that palmar sweating cannot be considered as a simple following of sympathetic discharge (Kerassidis 1997).

METHODS
PARTICIPANTS
Twenty: 10 hyperhidrotic in palms, mean age 33 years old (range 18-56) and 10 normal palmar sweating individuals, mean age 30 years old (range 20-62), participated in this experiment. Males were 5 and females also 5, in each group. These subjects had participated to our previous work on pathophysiology of palmar hyperhidrosis (kerassidis et al...). From the beginning of that work, in order to confirm the participants' estimate of the degree of their palmar sweating, a sweat collecting plaster was attached on each participant's left palm, while she/he was writing for two minutes on a paper with the right hand. The mean weight of the sweat collected from the palm of hyperhidrotics was 20 mg and from that of normal individuals 3.1 mg. Two subjects (one with 4 mg palmar sweating, who had declared hyperhidrotic and one with 12 mg, who had declared normal) were excluded from the analysis of the previous research. The 20 subjects of the present work (out of the 42 subjects of the previous) were undoubtedly well defined as hyperhidrotic or normal not only because of the writing test, but because the tasks of the previous work approved that as well.

MATERIALS
J&J Modules of Unicomp were used for the recording of conductivity of right palm. Electrodes of Ag-AgCl, 8 mm in diameter and electrolytic paste of Hewelett Packard were used. Frequent change of polarity and replacement of electrodes were used in order to prevent polarisation of the electrodes. An ink-pad and sheets of paper were used for fingerprinting.

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 to keep motionless the fingers with electrodes (thumb and middle finger), for 100 s. 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 touch paper (if a somatosensory feedback would be important).
Data analysis
We compared the number of electodermal responses (EDRs) and the mean skin conductance level (SCL), during every task. As EDR we accepted any increase in palmar conductivity over 0.03 μS, the mean SCL was calculated by the computer as the mean value of 20 mean values of SCL for 5 s each one. Analysis of variance (ANOVA)-Repeated Measures design was used. Namely, three factor ANOVA/MANOVA (multivariate ANOVA) with sex and hyperhidrosis as between-subject factors and repeated measures as within subject factor (2X2X2) were performed.

RESULTS
At first, we have to mention that the artefacts were kept at minimum despite the use of the palm, the recording of which was made, especially for 3 reasons: (i) during leafing the participants used only the forefinger but the recording electrodes attached to the thumb and the middle finger, (ii) during fingerprinting, when the participants made fingerprints of the recorded fingers they instructed to pouch carefully, and (iii) the .03 μS criterion for an EDR is slightly high (Levinson and Edelberg, 1985) so small alterations in skin conductance due to palm movement did not count as an EDR.
The results of the analysis are given on tables 1,2. As we can see, hyperhidrotics and females presented significantly higher SCL, during tasks, than normal and male individuals respectively. Group differences were due to the higher wetting of palmar stratum corneum of hyperhidrotics and sex differences to the thinner epidermis resulting to higher conductivity of woman palmar skin. No significant difference was revealed for EDRs either between hyperhidrotic and normal or between male and female individuals, during both tasks.
Within subjects differences caused by the two tasks was very significant. In both groups the number of EDRs during fingerprinting was decreased about in the half of those during leafing. The decrease of mean SCL from leafing to fingerprinting was about 30% for both groups.

DISCUSSION
We found that both hyperhidrotic in palms and normal palmar sweating subjects expressed significantly higher EDA during leafing (palmar wetting is desirable) than fingerprinting (palmar wetting is unwanted). Knowing that the differences in SCL may due to the prior of the tasks wetting of palmar stratum corneum, we can say that the electrodermal behaviour of hyperhidrotic and normal individuals was surpassingly comparable.
The finding for normal subjects replicated the finding of our previous similar experiment and confirmed the hypothesis that the magnitude of palmar sweating is influenced from the usefulness of palmar wetting in action. The fact that although the order between desirable and unwanted wetting of palms tasks was different than that of the previous experiment, the difference in palmar sweating between task was almost the same, indicate that this difference cannot be attributed to the order of the performance of the tasks. In addition, the fact that in both tasks of the present work, the fingers attached sheets of paper, indicate that the difference of the EDA between tasks cannot be attributed to an automatically activated, via a somatosensory feedback pathway, mechanism. That means that probably a cognitive appreciatory mechanism is responsible for the difference of EDA between tasks. It must be noted that for the present work is uninterested whether it was the belief of an individual (amplified by our instructions) or a conditioned response formed by its prior experience, about the functional significance of the wetting of palm, that caused the higher EDA. That was important to be determined was the potentiality of a purposeful modification of palmar sweating, beyond emotional load or sympathetic arousal.
For the hyperhidrotics, 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 differentiation of palmar sweating of normal individuals, indicates that no disruption of the appreciatory of usefulness mechanism takes place in the case of palmar hyperhidrosis. May that means that palmar hyperhidrosis is not a neurotic phenomenon, or that the muladaptiveness of the neurotic expression does not simply implies that the function is not related with the needs of action? We believe that the findings of the works mentioned in the introduction, in combination with the finding of this work, suggest the second view as correct.
But then, how can we explain the excessive palmar sweating of hyperhidrotics, during examinations, social relationships, writing, etc. when no benefit of palmar wetting in action exists? Even in the case of normal group, we faced this phenomenon in the second task when the palmar sweating of both groups was not zero, despite that it was absolutely undesirable. Obviously, the impact of the appreciatory mechanism is limited and it is superimposed to the impact of another, probably triggering more automatically the palmar sweating. The question is: does this triggering the palmar sweating mechanism activate the palmar sweat glands blindly, in the context of a general or sympathetic arousal, or a benefit beyond the palmar wetting is accomplished for the organism? Many findings of EDA research suggest that palmar sweating may be useful for other reasons to the organism beyond mechanical facilitation of the action, but since it cannot be supported by the findings of the present work, it must be the issue of another one.
What we can clearly concluded from the findings of this work is that palmar sweating is not unrelated to the action demands on palmar wetting, even in the case of palmar hyperhidrosis, and this obviously means that palmar sweating may not be considered a noisy manifestation of a non-specific activity (Fowles, 1986),.

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