Measurement of susceptibility to diabetic foot ulcers

Abstract

The present disclosure provides apparatuses and methods for measuring capacitance as an indication of susceptibility to the formation of a diabetic foot ulcer.

1 . An apparatus for assessing susceptibility of tissue to formation of a diabetic foot ulcer, said apparatus comprising:
 a plurality of electrodes embedded on a substrate, wherein a pair of said electrodes is capable of forming a capacitive sensor configured to measure a first capacitance of a first region of tissue proximate to said capacitive sensor,   a drive circuit electronically coupled to said electrodes,   a processor electronically coupled to said drive circuit, and   a non-transitory computer-readable medium electronically coupled to said processor and comprising instructions stored thereon that, when executed on said processor, perform the steps of:
 receiving information regarding said measured first capacitance from said drive circuit, 
 comparing said measured first capacitance to a first reference value, and 
 providing a signal if said measured first capacitance differs from said first reference value by an amount greater than a first predetermined threshold. 
   
     
     
         2 . The apparatus of  claim 1 , wherein said first reference value is predetermined. 
     
     
         3 . The apparatus of  claim 1 , wherein said first reference value is determined by measurement of said first capacitance at a time when said first region of tissue is healthy. 
     
     
         4 . The apparatus of  claim 1 , wherein said first reference value is determined from measurements of said first capacitance at said first region of tissue at one or more times prior to the most recent measurement of said first capacitance. 
     
     
         5 . The apparatus of  claim 1 , wherein said first reference value is determined by a measurement from a bisymmetric location. Page  3   
     
     
         6 . The apparatus of  claim 1 , wherein said first reference value is a measurement of a second capacitance of a second region of tissue that is separated from said first region of tissue. 
     
     
         7 . The apparatus of  claim 6 , wherein said second region of tissue is known to be healthy. 
     
     
         8 . The apparatus of  claim 6 , wherein said second capacitance is measured at approximately the same time as said first capacitance. 
     
     
         9 . The apparatus of  claim 1 , the apparatus further comprising one or more temperature sensors that are configured to measure a temperature of said first region of tissue and are coupled to said processor, wherein:
 said instructions further comprise:
 a step of receiving information regarding said measured temperature from said one or more temperature sensors, and 
 a step of comparing said measured temperature to a second reference value, and 
 a step of providing a signal comprising providing said signal if said measured first capacitance differs from said first reference value by an amount greater than said predetermined first threshold and said measured temperature differs from said second reference value by an amount greater than a predetermined second threshold. 
   
     
     
         10 . The apparatus of  claim 1 , the apparatus further comprising one or more optical sensors configured to image an underside of a foot of a patient while said patient is standing on said substrate. 
     
     
         11 . A method for assessing susceptibility of tissue to formation of a diabetic foot ulcer, said method comprising:
 obtaining a first capacitance value at a first location of a patient's skin;   obtaining a temperature measurement at said first location of a patient's skin; and   determining that said first location of a patient's skin is susceptible to formation of a diabetic foot ulcer when said first capacitance value differs from a first reference value by an amount greater than a first predetermined threshold and said temperature measurement differs from a second reference value by an amount greater than a second predetermined threshold.   
     
     
         12 . The method of  claim 11 , wherein said first reference value is predetermined. 
     
     
         13 . The method of  claim 11 , wherein said first reference value is determined by measurement of said first capacitance at a time when said first location of a patient's skin is healthy. 
     
     
         14 . The method of  claim 11 , wherein said first reference value is determined from measurements of said first capacitance at said first location of a patient's skin at one or more times prior to the most recent measurement of said first capacitance. 
     
     
         15 . The method of  claim 11 , wherein said first reference value is a measurement of a second capacitance of a second location of a patient's skin that is separated from said first location of a patient's skin. 
     
     
         16 . The method of  claim 15 , wherein said second region of a patient's skin is known to be healthy. 
     
     
         17 . The method of  claim 15 , wherein said second capacitance is measured at approximately the same time as said first capacitance. 
     
     
         18 .- 30 . (canceled) 
     
     
         31 . The apparatus of  claim 1 , the apparatus further comprising:
 at least two stimulus electrodes disposed on the substrate such that a portion of a current passing between a pair of the stimulus electrodes will pass through a portion of the first region of tissue; and   an external controller electrically connected to the at least two stimulus electrodes and configured to provide a therapeutic stimulus to the first region of tissue.   
     
     
         32 . The integrated apparatus of  claim 31 , wherein the external controller is further configured to control the two electrodes to detect conductive contact with the patient's skin during a sensing phase and to apply the therapeutic stimulus to the patient during a therapeutic phase.