Apparatus for evaluation of skin impedance variations

Abstract

The invention provides an apparatus and method for automatic evaluation of skin resistance or impedance variations in order to diagnose the state of health of at least a portion of a human or animal body. The difference between an AC impedance measured at a specific frequency and at a specific skin area with a calibration electrode and a reference electrode and the impedance measured at a similar frequency and in the same area with a measurement electrode and a reference electrode, is used to determine the state of health of the internal organ corresponding to the examined skin area. Alternatively, the skin between the electrodes is exposed to a DC potential of a magnitude selected to give a break-through effect. The resistance of the skin is measured between a measurement electrode polarised negatively with respect to a reference electrode, and the DC resistance of the same skin area is again measured but with the measurement electrode polarised positively with respect to the reference electrode. The ratio of these two values is used to determine the state of health of the internal organ corresponding with the examined skin area.

1 . An apparatus for diagnosing a state of health of an organ in a human or animal body, the apparatus including: 
 an electrical signal generator;    a calibration electrode, a measurement electrode, and a reference electrode, for connection, in use, to the generator, wherein one of the calibration and measurement electrodes is a point electrode having a small skin-contactable surface area, and the other electrode, respectively, has a significantly larger skin-contactable surface area than the point electrode;    recording means which is configured to record a first measured value of a first parameter which is dependent on the resistance or impedance between the calibration and reference electrodes when the calibration electrode is placed in contact with a first zone of skin corresponding to the organ and the reference electrode is placed in contact with another zone on the body, and an AC potential difference is applied between the calibration and reference electrodes by the generator;    recording means which is configured to record a second measured value of a second parameter which is dependent on the resistance or impedance between the measurement and reference electrodes when the calibration electrode has been replaced by the measurement electrode and the same AC potential difference is applied between the measurement and reference electrodes; and    means for comparing the first and second measured values to obtain a third value which is an indicator of the state of health of the organ to which the first zone of skin corresponds.    
     
     
         2 . An apparatus as claimed in  claim 1 , wherein the frequency of the AC signal is about 250 Hz.  
     
     
         3 . An apparatus as claimed in  claim 1 , which includes a display means for indicating the first zone of skin onto which the calibration and measurement electrodes should be placed in order to obtain a diagnosis for a particular organ.  
     
     
         4 . An apparatus as claimed in  claim 3 , wherein the display means indicates zones of skin which are located on a foot or an ear.  
     
     
         5 . An apparatus as claimed in  claim 4 , wherein the third value is expressed as a ratio of the first and second measured values.  
     
     
         6 . An apparatus as claimed in  claim 1 , which includes communication means for communicating, to an operator of the apparatus, the state of health of the diagnosed organ as being either healthy, normal, sub-acute or acute, depending on the third value.  
     
     
         7 . A method for diagnosing a state of health of an organ in a human or animal body, the method including the steps of: 
 placing a calibration electrode on or near a zone of skin which corresponds to the organ and placing a reference electrode in contact with another zone of skin on the same body;    recording a first measured value of a first parameter which is dependent on the resistance or impedance between the calibration and reference electrodes when an AC potential difference is applied between the calibration and reference electrodes;    replacing the calibration electrode with a measurement electrode, wherein one of the calibration and measurement electrodes is a point electrode having a small skin-contactable surface area, and the other electrode, respectively, has a significantly larger skin-contactable surface area than the point electrode;    recording a second measured value of a second parameter which is dependent on the resistance or impedance between the measurement and reference electrodes when the same AC potential difference is applied between the measurement and reference electrodes; and    comparing the first and second measured values to obtain a third value which is an indicator of the state of health of the organ to which the first zone of skin corresponds.    
     
     
         8 . A method as claimed in  claim 7 , wherein the frequency of the alternating current while obtaining the first and second values is about 250 Hz.  
     
     
         9 . A method as claimed in  claim 7 , wherein the third value is expressed as a ratio of the first and second values.  
     
     
         10 . A method as claimed in  claim 7 , wherein the measurement electrode is placed on an outer ear, or on a sole of a foot, having the zone of skin which corresponds to the organ.  
     
     
         11 . A method as claimed in  claim 10 , which includes the step of using a display means to indicate the zone of skin of a foot or an ear onto which the measurement electrode should be placed in order to obtain a diagnosis for a particular organ.