biologia - Studia

DIAGNOSIS BY ELECTRICAL RESISTANCE OF THE SKIN
Fig. 1. The Wheatstone bridge used in the measurements (Osiac et al., 2000)
Results
Because of the low number of participants included in the study, a statistical
analysis could not be performed. The results are based on individual cases,
eliminating the redundancy of presenting one pathological entity twice or more.
Testing the bridge. After the initial implement of the device, the bridge was
tested to verify its precision. It is a well-known fact that the electrical resistance of
the skin is modified by the subject's physical and mental state. With two electrodes
connected to the finger 2 and 4 of the left hand, the subject was asked to perform
some simple motor acts with the right hand, like making the fist. Then, the subject
was asked to cough and to keep his eyes closed for 10 seconds, followed by the
opening of the eyes.
At the beginning of the measurement, the electrical resistance was
increasing slightly, as the patient entered a relaxed state of mind. At the beginning of
the motor acts, the electrical resistance registered an abrupt decrease, for a few
seconds. Likewise, when the subject opened his eyes, after a few seconds of closure,
the electrical resistance slightly dropped (Fig. 2.).
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