AU2021104163A4

AU2021104163A4 - Device for measuring nerve conduction for early detection of diabetic neuropathy

Info

Publication number: AU2021104163A4
Application number: AU2021104163A
Authority: AU
Inventors: C. S. Charan; Hanumanthachar Joshi K.; Sourabh Kosey; Sandhya P.; Bhagawati Saxena; Chandrashekhar D. Upasani; Pranay Wal
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2022-05-19
Anticipated expiration: 2029-07-15

Abstract

: Disclosed herein a device and method for performing the sural nerve conduction test to accurately assess the nerve damage for early detection of Diabetic Peripheral Neuropathy (DPN) by measuring the onset sural nerve conduction velocity, sensory response amplitude The device compares the measured nerve parameters with standard data to calculate the nerve damage and displays the result in a display unit. For conducting the test, a cuff is wrapped over the leg of the patient to determine the exact location of the sural nerve region and contains an array of simulation electrodes that can send the electrical pulses to the wide area of sural nerve / muscle region and a wide array of bio-sensing electrodes for sensing and signal acquisition. 1 DRAWINGS: FIG. 1 is a flowchart representing the working methodology of the device of the present invention. Electrical Pulse input from the device to muscle/ sural nerve Bio-Potential Signal Signal Processing for DAC & Generate Signal Acquisitio Manipulation & 10 NCV and Muscle 10 Output Signal for s -onHADC Parameter Calculation Display Display Device FIG. 2 is a block diagram representing the simulation unit of the device of the present invention. Power ON/OFF Battery Box Microcontraller To-Simulation Timing Circuit electrodes

Description

DRAWINGS:

FIG. 1 is a flowchart representing the working methodology of the device of the present invention.

Electrical Pulse input from the device to muscle/ sural nerve

Bio-Potential Signal Signal Processing for DAC & Generate

Manipulation & 10 NCV and Muscle 10 Output Signal for s Signal Acquisitio -onHADC Parameter Calculation Display

Display Device

FIG. 2 is a block diagram representing the simulation unit of the device of the present invention.

Power ON/OFF

Battery Box Microcontraller To-Simulation

Timing Circuit electrodes

Title of Invention DEVICE FOR MEASURING NERVE CONDUCTION FOR EARLY DETECTION OF DIABETIC NEUROPATHY

Field of Invention

The present invention relates to the apparatus and method for the assessment of sural nerve conduction velocity, nerve conduction amplitude for estimating Diabetic Peripheral Neuropathy (DPN) severity & for peripheral nerve damage.

BACKGROUND OF THE INVENTION:

Diabetes is a common disease that affects adults, adolescents, children and now-a-days new-born child also suffers because of this disease.

Diabetes is strongly associated with both microvascular and macrovascular complications. Macrovascular complications refer to cardiovascular events such as myocardial infarction ("heart attack") and stroke. Microvascular complications refer to pathological damage to the nerves, eyes and kidneys of people with Diabetes mellitus (DM). The most common micro-vascular complication of DM is nerve damage or Diabetic neuropathy. This affects 60% or more people with DM.

The most common form of diabetic neuropathy is large fiber form of disease which is known as diabetic peripheral neuropathy (DPN). DPN typically affects the feet and legs and sometimes affects the hands and arms. Because of severe consequences of DPN, its early detection becomes paramount important in order to implement remedial strategies for intervention or slow down progression of neuropathy. Unfortunately, detection of DPN is challenging specially at the early stage.

Current method for clinical detection and monitoring DPN includes clinical evaluations (by physician) and several clinical tests that includes 10 gm mono-filament test and tuning fork test (both graduated and ungraduated). All the above mentioned methods are not only subjective to many factors like patient condition, instructor-patient interaction etc., but also results in time consuming and having poor sensitivity and lack of specificity. Further, the availability of these examinations is almost NIL for people residing in rural areas. Due to this, there is a need of simple, fast, reliable and accurate device which can perform well under any circumstances.

Also, an Electromyogram (EMG) testing have been proposed to detect the abnormal electrical activity of the muscles that can occur in many conditions, including identify muscular dystrophy, inflammation of muscles, pinched nerves, peripheral nerve damage (damage to nerves in the arms and legs), amyotrophic lateral sclerosis (ALS), myasthenia gravis, disc herniation, and others.

A Nerve Conduction Velocity (NCV) test is another option to identify nerve damage. This test measures how fast an electrical impulse moves through the nerve and helps to find the presence, location and extent of diseases that damage the nerves. Unlike the aforementioned techniques, NCV testing is reliable and reproducible diagnosis method for DPN. However due to limited availability, the complexity and high cost of the study, the NCV test is not currently used for assessing DPN.

A number of general purpose devices to identify nerve damage have been proposed in the existing art. United States Number 5,851,191 to Gozani, entitled "Apparatus and methods for assessment of neuromuscular function" describes a device and method for the assessment of neuromuscular function, where the device is used over the wrist and then analyses the nerve damage across the wrist by measuring the delay between the stimulation of the nerve and detection of muscular response to that stimulation.

United States Number 7,917,201 to Gozani, et al., entitled "Method and apparatus for determining optimal neuromuscular detection sites, novel diagnostic biosensor array formed in accordance with the same, and novel method for testing a patient using the novel diagnostic biosensor array" describes the method and apparatus for determining the optimal neuromuscular sites and novel diagnostic biosensor array for testing neuromuscular function. This apparatus is used for carpal tunnel syndrome.

Even though, these general purpose devices determine neuromuscular function they failed to adapt the variation in anatomical and electro-physiological aspects of many different nerves. Moreover, for the assessment of DPN, electro-physiology of sural nerve is considered as a "Gold Standard". However, none of the device disclosed in above prior art is designed for sural nerve region for assessing DPN.

United States Number 9,173,581 to Boettcher, et al., entitled "Apparatus and method for the automated measurement of sural nerve conduction velocity and amplitude" describes an apparatus and method for the automated measurement of sural nerve conduction velocity and amplitude for DPN detection. However, the existing device is not user friendly and always need medical expert to use the device, to find the exact location of sural nerve and to understand the output.

Therefore, it is desirable to provide a simple, economic, user friendly, easy to operate and reliable device so that a layman can also use the device on sural nerve for accurate assessment of DPN and also extent of DPN.

SUMMARY OF THE INVENTION:

An object of the present invention is to develop a portable, fully-integrated and cost-effective device for accurate assessment of extent of nerve damage to detect Diabetic Peripheral Neuropathy (DPN) severity.

According to the present invention, the device employs a method for quickly assessing DPN by measuring sural nerve conduction velocity, nerve conduction amplitude through nerve conduction velocity (NCV) test.

In accordance with the present invention, the device is provided with a cuff that consists of plurality of simulating and sensing electrodes to determine the exact location of sural nerve region. After placing the electrodes on sural nerve, the device performs the nerve conduction velocity (NCV) test to determine common sural nerve conduction parameters such as: the onset conduction velocity, sensory response amplitude.

In order to overcome the location uncertainty, the device of the present invention is provided with a plurality of electrodes in a cuff which contains an array of simulation electrodes that sends the electrical pulses to the wide area of sural nerve region and muscle region and a wide array of bio-sensing electrodes for sensing and signal acquisition. Such that a layman can also use this device for DNP assessment and thus making it user-friendly.

Other objects, advantages and features of the present invention will become more apparent from the following detailed description and claims, taken in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed for the purpose of illustration only and are not intended as a definition of the limits of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS:

The objective of the present invention will now be described in more detail with reference to the accompanying drawings, in which:

FIG. 1 is a flowchart representing the working methodology of the device of the present invention;

FIG. 2 is a block diagram representing the simulation unit of the device of the present invention;

FIG. 3 is a block diagram representing the signal processing / microcontroller unit of the device of the present invention.

DETAILED DESCRIPTION OF THE INVENTION:

The present invention provides a portable, fully-integrated and cost-effective device for accurate assessment of nerve damage to estimate Diabetic Peripheral Neuropathy (DPN) severity.

The purpose of the proposed device is to accurately measure and report sural nerve conduction parameters such as the onset conduction velocity and sensory response amplitude.

According to the present invention, the device comprises a housing, a battery, a user interface, a cuff, a simulation unit, a signal manipulation unit, a signal processing unit and a display unit.

In accordance with the present invention, the housing is used to cover all the units or components of the device; the battery box is used to place all the required batteries; the user interface is used to control the device operation that includes ON/OFF key, toe LED indicator and SEND PULSE Key; the simulation unit is used to generate the electrical pulse required for sural nerve conduction test and EMG test in order to measure the nerve conduction parameters and muscle strength parameters respectively; the cuff that consists of an array of simulation electrodes, an array of sensing electrodes and an electrodes assembly unit; the signal manipulation unit that consists of filters, smoothing circuit, amplifier and analog to digital converters; the signal processing unit that consists of microcontroller to control the entire operation of the device from the power input to final report generation by software based control; and the display unit is used to show test results and is of user-friendly.

The cuff of the present invention consists of: a) an array of simulation electrodes to transfer the electrical simulation from electronic circuit to sural nerve region and muscle region; b) an array of sensing electrodes to sense the electrical activity in the body and provide low impedance path to the electrical simulation; and c) an electrodes assembly unit that provide the housing to simulation electrodes and sensing electrodes.

In accordance with the present invention, the device performs the nerve conduction velocity (NCV) test to determine sural nerve conduction parameters such as: the onset conduction velocity and sensory response amplitude.. Then, the device compares the measured nerve conduction parameters with standard data to calculate the extent of nerve damage and displays the result in a display unit of the device.

The working methodology of the present invention device is shown in FIG. 1. First, the device waits for power input, upon the pressing of test button. In case of insufficient power, there displays an error message indicating the need for battery replacement. After getting sufficient power input, again the device waits for pulse input from external event which may be any one of them: send pulse button pressed, response from bio-sensor unit, input from user.

Upon pressing the send button key, the microcontroller checks proper electrodes connection and then sends the electrical stimulation. LED indicator represents the transmission (Tx) and receiving (Rx) status of the electrical pulse/signal. Tx/Rx status is also visible on the display by downward and upward arrow respectively. After receiving sufficient response from signal acquisition unit, signal is processed further by microcontroller circuit to get the nerve conduction parameters and muscle parameter as shown in FIG. 1. And then the results are displayed in the display unit of the device.

With respect to the above description, in order to estimate Diabetic Peripheral Neuropathy (DPN) severity the following test is carried out.

The NCV test is carried out to measure the nerve conduction parameters. In order to perform this EMG test, the electrodes are inserted into the nerves and the signals are transmitted. The nerve conduction parameters are measured based on the duration of signal transmission i.e., how long it takes the nerves to transmit the signals. Because the damaged nerves don't transmit messages as quickly as the undamaged nerves. Hence, based on the signal transmission, the NCV parameters are measured.

The above test is performed on tibial, sural, medial plantar, lateral plantar, median and ulnar nerves, which provides the seriousness of the diseases. The test can be done on sural nerve for accurate measurement. These tests can be performed on mainly on leg and but can be performed in hand also. in case of hand, they are least affected as compared to foot which is at the bottom of the body. Hence, there is more chances of deposition of sugar in nerves and veins.

In accordance with the present invention, the housing is the external cover of the device to cover all the units/components of the device and provide security from mechanical damage. The battery box is the energy house of the device where all the required batteries are placed and connected to microcontroller unit for power flow control. The User interface is used for controlling the operation of the device. There is a power ON/OFF key, toe LED indicator and SEND PULSE Key. The toe LED indicator has two indications i.e., one for power indicator where indication of green represents the running operation and another for transmitting and receiving status. The SEND PULSE Key is controlled by microcontroller circuit for timing control. Once the SEND PULSE Key is pressed, timing for continuous pulse transmission is initiated for around 10-12 seconds. Then, the pulse transmission is automatically turned OFF.

FIG. 2 shows the block diagram representing the simulation unit of the present invention. This unit generates the electrical pulse required for nerve conduction test and for EMG test. The electrical pulses is a DC voltage of range 10-20 volts and current up to 1 mA and not more than 1 mA. The simulation unit is controlled by microcontroller timing circuit that consists of timing circuitry which allow the electrical simulation to flow in the human body up to 10-12 seconds.

As shown in FIG. 2, the simulation electrodes are connected to simulation unit which act as a medium to transfer the electrical simulation from electronic circuit to sural nerve region and muscle region. While conducting the test, sometimes it is difficult to determine the exact location of sural nerve region. In the preferred embodiment of the present invention, a plurality of electrodes are used to overcome the location uncertainty and all of the simulation electrodes transmit same electrical simulation to the body.

The sensing electrodes of the device senses the electrical activity in the body and provides low impedance path to the electrical simulation and forward to bio-potential signal acquisition and filtration unit. The electrodes assembly unit provides a housing for simulation electrodes and sensing electrodes.

According to the present invention, the cuff consists of all the necessary electrodes for simulation and sensing purpose with their assembly unit. The cuff is need to be wrapped over the sural nerve region of the patient for nerve conduction test. Both simulation electrodes are placed on underneath side of the cuff which is in contact with patient skin. The Simulation electrodes are placed first on the top of underneath side and the sensing electrodes are placed were sural nerve touches Achilles' tendon.

FIG. 3 shows a signal processing unit that consists of microcontroller which controls the entire operation of the device from the power input to final report generation by software-based control installed on the microcontroller.

The device of the present invention consists of display which is user friendly and self explanatory. The display unit shows test results both graphically and numerically. In addition, the electrodes connection status (both transmitting and receiving status) and the device status (e.g. battery status, device input-output configuration etc.) are also shown in the display unit of the device.

Accompanying the above description of the construction of the device, the method for performing the sural nerve conduction test according to the present invention to detect Diabetic Peripheral Neuropathy (DPN) at early stage is explained in detail comprising the following steps: a) wrapping the cuff over leg of the patient; b) pressing the power button to input power to the device; c) upon receiving sufficient power, the electrical simulation is sent to sural nerve region/ muscle region via simulation electrodes placed on the cuff by inputting the pulse from external event; d) sensing the electrical activity of the sural nerve / muscle region and providing the low impedance path to the electrical simulation with bio signal sensing electrodes placed on the cuff; e) acquisition of bio-potential signal using the signal acquisition unit; f) filtering, smoothing and amplifying the signal using the signal manipulation unit; g) processing the signal with the signal processing unit that consists of a microcontroller to get the sural nerve conduction parameters and muscle strength parameters; h) comparing the obtained/measured nerve conduction parameters and muscle strength parameters with standard data to calculate the extent of nerve damage; and i) displaying the test results on a display unit of the device.

According to the present invention, the cuff is wrapped over the leg of the patient for nerve conduction test to determine exact location of the sural nerve region and thereby overcome location uncertainty. That is, the cuff contains an array of simulation electrodes that can send the electrical pulses to the wide area of sural nerve region and a wide array of bio-sensing electrodes for sensing and signal acquisition. So that, a layman can also use this device for assessing the nerve parameters and muscle strength parameters without the need of medical expert.

In accordance with the present invention, the cuff can be wrapped either to the left or the right leg of the patient depending on the affected area as the limb impedance of both the leg are equal.

The cuff is placed against the patient sural nerve such that cathode is located over the sural nerve as the sural nerve passes behind lateral malleolus and sensing unit is located over the sural nerve as nerve approached the Achilles tendon about 9 cm from cathode. After placing the electrodes on sural nerve, the device performs the nerve conduction velocity (NCV) test to determine sural nerve conduction parameters such as, the onset conduction velocity and sensory response amplitude Further, the device compares the measured nerve conduction parameters and muscle strength parameters with standard data to calculate the extent of nerve damage and displays the result in a display unit of the device.

Thus, the present invention provides a user-friendly design for accurate assessment of sural nerve parameters without any location uncertainty, thereby aid in accurate detection of DPN at the early stage.

While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above-describedembodiment, method, and examples, but by all embodiments and methods within the scope of the invention as claimed.

Claims

We Claim:

1. A device for performing a sural nerve conduction test to assess the extent of nerve damage for Diabetic Peripheral Neuropathy (DPN) detection wherein the device comprising: a) a housing to cover all the units or components of the device; b) a battery box to place all the required batteries; c) a user interface to control the device operation that includes ON/OFF key, toe LED indicator and SEND PULSE Key; d) a simulation unit to generate the electrical pulse required for the sural nerve conduction test and the EMG test; e) a cuff, wherein the cuff consists of: i. an array of simulation electrodes to transfer the electrical simulation from electronic circuit to sural nerve / muscle region; ii. an array of sensing electrodes to sense the electrical activity in the body and provide low impedance path to the electrical simulation; iii. an electrodes assembly unit that provide the housing to simulation electrodes and sensing electrodes; f) a signal manipulation unit that consists of filters, smoothing circuit, amplifier and analog to digital converters; g) a signal processing unit that consists of microcontroller to control the entire operation of the device from the power input to final report generation by software based control; and h) a display unit to show test results.

2. The device as claimed in claim 1, wherein the device performs the nerve conductivity test to measure sural nerve parameters such as onset conduction velocity and sensory response amplitude.

3. The device as claimed in claim 1, wherein the simulation electrodes are placed first on the top of underneath side of the cuff and the sensing electrodes are placed where sural nerve touches Achilles tendon.

4. The device as claimed in claim 1, wherein the simulation electrodes are inserted into the nerves for performing the nerve conductivity test.

5. The device according to claim 1, wherein the display unit further shows the electrodes connection status and the device status.

6. A method for performing a sural nerve conduction test comprises the steps of: a) wrapping a cuff over leg of the patient; b) pressing the power button to input power to the device; c) sending the electrical simulation to sural nerve / muscle region via simulation electrodes placed on the cuff by inputting the pulse from external event; d) sensing the electrical activity of the sural nerve / muscle region and providing the low impedance path to the electrical simulation with bio signal sensing electrodes placed on the cuff; e) acquisition of bio-potential signal with a signal acquisition unit; f) filtering, smoothing and amplifying the signal with a signal manipulation unit; g) processing the signal with a signal processing unit that consists of a microcontroller to get the sural nerve conduction parameters h) comparing the obtained/measured nerve conduction parameters with standard data to calculate the extent of nerve damage; and i) displaying the test results on a display unit of the device.

7. The method as claimed in claim 6, wherein the external event can be any one of: send pulse button pressed, response from bio-sensor unit or input from user.