Semi-automated plantar surface sensation detection device

Abstract

Disclosed herein is a device for repeatably and accurately measuring the threshold sensitivity of the skin on a body part or surface such as the plantar surface of the foot. The machine uses a monofilament pressure test, where a monofilament is applied to the surface of the skin until it buckles at a corresponding force. The device may measure a broad range of pressures and responsive sensation in the patient using multiple applications of the monofilament. The patient indicates a positive or negative response, based on whether the patient sensed the monofilament pressure. The machine may include a foot clamping assembly, a support chassis, a linear motion translation assembly for locating the monofilament at a given position for testing, and a camera for taking images used to identify testing locations and report results. Methods of use and testing protocols are also described herein.

We claim: 
     
         1 . A machine for evaluating the presence of neuropathy in a patient, comprising:
 a testing plate having a first side and a second side and comprising a plurality of holes, and configured to have the patient's skin stabilized against the first side;   a camera operable to take a photograph of the patient's skin visible through the holes from the second side of the testing plate;   a head assembly translatable within a plane parallel to the second side of the testing plate and disposed in between the camera and the testing plate, the head assembly comprising a retractable monofilament; and   a computer programmed to
 receive input for selecting a testing location on the patient's skin wherein the testing location is correlated with one of the plurality of holes in the testing plate, 
 position the head assembly over the testing location, and 
 apply the monofilament to the patient's skin at the testing location and at a specified force. 
   
     
     
         2 . The machine of  claim 1 , further comprising a linear translation assembly mounted to the chassis and having first and second translation motors and a drive train connected to the head assembly, such that the translation motors cause the head assembly to be movable in an X/Y-plane parallel to the second side of the testing plate. 
     
     
         3 . The machine of  claim 1  wherein operation can be semi-automatic. 
     
     
         4 . The machine of  claim 1  wherein the force applied ranges from about 0.2 to about 30 gF. 
     
     
         5 . The machine of  claim 1  wherein the same monofilament can be used to apply different forces. 
     
     
         6 . The machine of  claim 1  wherein the testing plate is transparent. 
     
     
         7 . The machine of  claim 1  wherein the computer is programmed to receive the image and to receive input for selecting a testing location by designating a location on the image. 
     
     
         8 . The machine of  claim 7  wherein the computer is further programmed to provide an output comprising an image of the patient's skin with the force testing information applied at the testing location. 
     
     
         9 . The machine of  claim 8  wherein the computer is further programmed to store testing information. 
     
     
         10 . The machine of  claim 1  wherein the patient's skin being tested is the plantar surface of a foot of the patient. 
     
     
         11 . The machine of  claim 1  further comprising a clamp for securing the patient's skin to the first side of the testing plate. 
     
     
         12 . A machine for evaluating the presence of neuropathy in a patient, comprising:
 a testing plate having a first side and a second side and comprising a plurality of holes, wherein the patient's skin may be stabilized against the first side of the testing plate;   a camera operable to take a photograph of the patient's skin visible through the holes from the second side of the testing plate;   a head assembly translatable within a plane parallel to the second side of the testing plate, the head assembly comprising a retractable monofilament;   a chassis having a first side to which the testing plate is secured, and a second side opposite the first side to which the head assembly is secured, wherein the camera is mounted to the chassis and is disposed external to the chassis; and   a computer programmed to
 receive input for selecting a testing location on the patient's skin wherein the testing location is correlated with one of the plurality of holes in the testing plate, 
 position the head assembly over the testing location, and 
 apply the monofilament to the patient's skin at the testing location and at a specified force. 
   
     
     
         13 . The machine of  claim 12  wherein operation can be semi-automatic. 
     
     
         14 . The machine of  claim 12  wherein the force applied ranges from about 0.2 to about 30 gF. 
     
     
         15 . The machine of  claim 12  wherein the force applied ranges from about 0.2 to about 10 gF. 
     
     
         16 . The machine of  claim 12  wherein the testing plate is transparent. 
     
     
         17 . The machine of  claim 12  wherein the computer is programmed to receive the image and to receive input for selecting a testing location by designating a location on the image. 
     
     
         18 . The machine of  claim 17  wherein the computer is further programmed to provide an output comprising an image of the patient's skin with the force testing information applied at the testing location. 
     
     
         19 . The machine of  claim 18  wherein the computer is further programmed to store testing information. 
     
     
         20 . The machine of  claim 12  wherein the patient's skin being tested is the plantar surface of a foot of the patient.