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Quantification of Hyperhidrosis using Electronic Sudometer
KTH, School of Technology and Health (STH).
2013 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Human skin has various pathologies in the form of acute and chronic diseases. Some are only cosmetic diseases which are not harmful for life but they can affect mental health and disrupt daily activities. Hyperhidrosis is one of these cosmetic diseases which may be caused by diabetes, infections, or thyroid hyper activity, or can be inherited. There are some examinations for testing hyperhidrosis, e.g. gravimetric and minor starch-iodine test. There are some devices that can measure sweat but are not specifically used or even intended for use on hyperhidrosis.

A non-invasive prototype instrument called Electronic Sudometer using the principle of electrical impedance measurement has been developed. The philosophy behind this prototype is to make an instrument which can detect hyperhidrosis during homeostasis as well as in pathological condition. The device injects a sinusoid electric current and detects the ensuing voltage, which is proportional to the impedance of sweat on top of the skin during hyperhidrosis. For this prototype, the electrode system is made of brass rings mounted on a handle. The signal is then processed in electronic assembly. Processed output is transferred to a Laptop with specially made connecting wire. Computer having Sound Card Oscilloscope (Lab View based software) plots the signal and shows voltage level corresponding to sudor level. The signal output can also be displayed on a SmartPhone having software called Osciprime, requiring another specially made interface.

Laboratory test results in the form of a plot of output voltage vs. impedance show accuracy of the device. The impedance results can be translated to sweat level because impedance decreases with increasing sweat during hyperhidrosis. The Sudometer was also calibrated using fixed precision resistors over its working range. Laboratory tests were carried out using an artificial skin at various sweat levels and to a yeast tissue model. Hydration of the artificial skin was quantified by weighing precision cut samples on a laboratory balance. Results from two test persons (the author and a student friend) are also included in this Master Thesis. During these experiments, the laptop computer and SmartPhone, respectively, were on internal battery to eliminate electric hazard.

Any clinical device must be validated for accuracy and evaluated for safety before applying it on patients – the latter has not been done with the prototype. The author is aware of potential electrical risks, and thus the whole system was disconnected from mains 230V during measurements on himself and a student friend. The device output seems to be well correlated to sweat level although electrolytes were not taken into account. Being a palmar hyperhidrosis patient himself, the author applied the Electronic Sudometer on his palms and the results look quite promising. At different environmental temperatures, the author checked elicited sweat responses. Patient safety is always a concern for clinicians regarding new devices. For this reason, the device itself has been made battery operated, and a new version will be entirely powered from a SmartPhone.

Place, publisher, year, edition, pages
2013. , 44 p.
Trita-STH, 2013:105
Keyword [en]
Electronic Sudometer, Hyperhidrosis
National Category
Medical Engineering
URN: urn:nbn:se:kth:diva-132250OAI: diva2:659303
Subject / course
Medical Engineering
Educational program
Master of Science - Medical Engineering
Available from: 2013-11-04 Created: 2013-10-25 Last updated: 2013-11-04Bibliographically approved

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