1. Field of the Invention
This invention relates to devices used to measure nerve conduction in peripheral nerves and more particularly, to such devices that measure the conduction time and amplitude of a test signal applied to a nerve.
2. Description of the Related Art
It is common practice in medicine to measure the electrical conduction on a peripheral nerve. For example, when diagnosing carpel tunnel syndrome it is common for a physician to measure the electrical conduction in the median nerve as it extends from the forearm, through the wrist and into the hand. During the test procedure, the physician measures the length of time and the amplitude of a test signal applied to the nerve having a known length. To perform the test, recording sensors are attached to the patient's forearm and a nerve stimulator is positioned over the nerve.
When testing for carpel tunnel syndrome, the recording sensors and the nerve stimulator's cathode probe must be spaced apart at selected distances (8 cm, 10 cm, and 14 cm) on the hand and forearm. Heretofore, physicians have used a ruler or measuring tape and an ink marker to first mark the specific locations of the recording electrodes and the nerve stimulator on the patient's skin before the test is performed. Often, several tests are performed on the same hand and forearm during the visit, which requires manually marking the skin reference points. The act of measuring and marking several sets of reference points on the forearm and hand is very time consuming. Also, because the sets of reference points are relatively close, a wrong set of reference points may be used during the test that produces inaccurate readings.
It is an object of the present invention to provide a nerve stimulator measuring device that enables a physician to easily and quickly determine the proper position of the nerve stimulator.
It is another object of the invention to provide such a device that may be used with a standard electrical nerve stimulator that uses a cathode probe and an anode probe that are positioned against or adjacent to the skin.
It is another object of the invention to provide such a device that enables a physician to determine different locations of the cathode probe from the electrical sensor without using an ink marker.
It is another object of the invention to provide such a device that is wireless thereby eliminating wires that typically extend from the device to the recording machine.
These and other objects are met by the nerve stimulator measuring device with a tape measure attached thereto used to measure the distance between the electrical sensor and the cathode probe. In the first embodiment, the tape measure is located in an outer housing that attaches or is integrally formed on the cathode probe on a standard electrical nerve stimulator. The outer housing includes two bores designed to receive the anode and cathode probes on the electrical nerve stimulator. During assembly, the outer housing is positioned over the two probes with the tape measure disposed therebetween. An index marking or line formed on the outer surface of the outer housing is aligned with the center axis on the cathode probe.
In a second embodiment, the nerve stimulator comprises an outer housing with a tape receiver cavity formed there that holds a spool upon which a flexible tape measure is wound and unwound. The spool is coupled to a tape retraction mechanism that automatically rewinds the tape measure on the spool. Mounted on the outer surface of the outer housing is a stimulator activation button coupled to an electric test signal generator and a tape retraction button coupled to the tape retraction mechanism.
In the second embodiment, disposed on the distal end of the tape measure used with the second embodiment, are three recording sensors. Wires extend from the three recording sensors to an optional wireless transmitter located inside the outer housing. During operation, the wireless transmitter transmits the detected electrical signal information from the sensors to a wireless receiver connected to a nearby recording machine. The three wires that connect to the three recording sensors are mounted on the tape measure and are extended and retracted into the outer housing with the tape measure. Also mounted on the outer housing is a signal intensity control switch that the user manually operates to adjust the size of the signal generated by the stimulator probes.
In three other embodiments of the invention, a linear skin distance measuring device is attached to the electrical nerve stimulator. In two embodiments, a linear skin distance measuring device is attached to one or both probes on the electrical nerve stimulator. In another embodiment, the linear skin distance measuring device is attached to the body of the electrical nerve stimulator. In each embodiment, the linear skin distance measuring device is designed to measure the distance the electrical nerve stimulator travels moved to a desired location on the skin over the nerve to be tested from an electrode sensor attached to the skin. An electric nerve generator is connected to the anode and cathode probes on the electrical nerve stimulator. The electrical nerve stimulator is positioned over the electrode sensor and then manually moved to the desired location over the nerve. A display on the device informs the healthcare worker the precise distance traveled. When the desired distance is achieved, the test is then performed.
When the first embodiment is used to diagnose carpel tunnel syndrome, the recording sensors are first attached to the forearm over the median nerve. The free end of the tape measure is then centrally aligned over the first recording sensor and the electrical stimulator with the outer housing attached thereto is pulled towards the hand to the desired length (8 cm, 10 cm, or 14 cm) required for the test. The electrical nerve stimulator is then held so that the cathode probe is aligned on the skin adjacent to the desired distance on the tape. The electrical nerve stimulator is then activated and a reading is obtained. When additional tests are to be conducted, the recording sensor is again used as a reference point for the free end of the tape. The electric nerve stimulator is moved to the new testing point so that the desired distance is displayed on the tape. The electrical nerve stimulator is then held so that the cathode probe is then pressed against the skin adjacent to the new distance.
When the second embodiment is used to diagnose carpel tunnel syndrome, the end of the tape measure is pulled from the outer housing so that the three electrical sensors are longitudinally aligned at a desired location of a desired nerve on the forearm. The outer housing is then pulled towards the hand so that the anode and cathode stimulator prongs are positioned at a desired location. (8 cm, 10 cm, or 14 cm) on the tape measure. The stimulator button is then pressed to activate the electrical nerve stimulator. The optional signal intensity switch is used to adjust the desired signal intensity. When additional tests are to be conducted, the nerve sensor probes are moved to a new location on the tape measure and the stimulator button is activated. When the test is completed the tape retraction button is activated to automatically retract the tape measure into the outer housing.
In the third and fourth embodiments, the handheld electrical nerve stimulator is perpendicularly aligned over the skin adjacent to an electrode sensor. The distance measuring device is then activated and begins to measure the distance the handheld electrical nerve stimulator is moved over the surface of the skin. When the handheld electrical nerve stimulator is positioned at the desired location on the skin, the distance reading on the display is then recorded and the two probes are then pressed the skin. The electric nerve generator is then activated and a test is then conducted.
Shown in the accompanying
Located inside the outer housing 20 is a retractable spool 31 with a flexible tape 30 with length measure units 32 printed thereon. In the preferred embodiment, the two ears 11, 12 include two bores 24, 26 designed to slidingly receive the anode and cathode probes, 78, 80 respectively. The outer housing 20 is aligned on the probes 78, 80 so that the tape measure 30 unwinds around a center axis that is perpendicular to the longitudinal axis of the two probes 78, 80.
The second embodiment of the device 10′, shown in
In the first three embodiments 10, 10′, 10″, an optional index marking or surface 84 may be printed or formed on the outer body 20, 20′, or 20″ that denotes the reference point for the tape measure 30.
As shown in
When using the third embodiment of the device 10″, the electro-magnetic stimulator 85 is held so that the center axis of the central opening 89 is longitudinally aligned over the nerve 95. The stimulator 85 is held so that the exit port 88 of the device 10″ is positioned directly over the nerve 95. The end of the tape measure 30 is then pulled and positioned over the sensor. The distance indicia on the tape measure 30 at the exit port 88 or surface 84 is then read. With devices 10, 10′ and 10″, the recording sensors 90 and 92 may be attached or formed in the distal end of the tape measure 30. As shown in
Shown in the accompanying
The three recording sensors 43, 44, 45 are mounted longitudinally near the distal end 31 of the tape measure 30. Printed on the front surface 32 of the tape measure 30 are metric or English distance markings 36 that enable the user to determine the distance from the closest recording sensor. Also mounted on the outer surface of the outer housing 20′″ is a tape retraction button 65 coupled to the tape retraction mechanism 39 which when activated, automatically retracts the tape measure 30 into the outer housing 12.
As shown in
Located inside the outer housing 20′″ is an optional wireless transmitter 55 connected printed circuit board 48. During operation, the wireless transmitter 55 transmits detected electrical signal information from three sensors 43, 44, 45 to a wireless receiver 58 connected to a nearby recording machine 60 shown in
When device 10′″ is used to diagnose carpel tunnel syndrome, the distal end 31 of the tape measure 30 is pulled from the outer housing 12 so that the three electrical sensors 43, 44, 45 are aligned at the desired location on the hand 82. The outer housing 20′″ is then pulled so that the anode and cathode stimulator prongs 78, 80 are positioned at a desired location (8 cm, 10 cm, or 14 cm) on the tape measure 30 along the forearm. The stimulator button 50 is then pressed to activate the electrical test signal generator 49. The optional signal intensity dial 52 is used to adjust the signal intensity. When additional tests are to be conducted, the nerve sensor probes 78, 80 are moved to a new location on the tape measure 30 and the stimulator button 50 is activated. When the test is completed the tape retraction button 65 is activated to automatically retract the tape measure 30 into the outer housing 20′″.
The lower platform 210 includes two bores 212, 214, designed to slide over the two probes 78, 80, respectively. The rotating wheel 220 is mounted on an axle 221 held between two, transversely aligned, rigid supports 222, 224 that extend downward from the lower platform 210. A transducer 228 is provided for converting the rotational movement into a digital format. The two rigid supports 222, 224 are parallel and spaced apart so that the rotating wheel 220 may rotate freely between them. The rigid supports 222, 224 are also slightly shorter than the diameter of the rotating wheel 220 so that the two supports 222, 224 are above the skin 99 as the lower surface of the rotating wheel 220 contacts and rotate over the skin 99. During use, the rotating wheel 220 rolls over the skin surface when the nerve stimulator 70 is moved laterally (directions f1 and f2) as shown in
As shown in
In the preferred embodiment, the rotating wheel 220 is biased upward towards the main body 205 when not in use thereby enabling the nerve stimulator 70 to be used in a normally manner without the linear distance measuring device 200. Attached to the two support arms 222, 224 are two t-shaped posts, 225, 227, respectively, that extend vertically upward and into a void space created inside the main body 205. Springs 236, 238 are attached to the two posts 225, 227, respectively, which press against the inside surface of the main body 205 to biased the lower platform 210 upward.
The main body 305 includes display 330, a PCB 336, a battery 338 and an ON/OFF switch 342 and a RESET switch 344. The lower platform 310 includes a rear cylindrical member 318 that slides over one probe 78 or 80. Located in front of the cylindrical member 318 is a rigid support member 338. A rotating wheel 320 is mounted on an axle 321 and inside the space created between the cylindrical member 318 and the rigid member 338. Located inside is a transducer 328 used to convert rotational movement into a digital format.
The lower platform 310 is sufficiently wide and long so that a portion of the lower platform 310 extends laterally and forward to the main body 305 and exposed. The exposed portions may be used as pressing surfaces for the user's finger tips to press the lower platform 310 and the rotating wheel 320 when moving the nerve stimulator 70 into a desired location.
In each embodiment, the linear skin distance measuring device 200, 300 is designed to measure the distance the electrical nerve stimulator travels moved to a desired location on the skin over the nerve to be tested from an electrode sensor attached to the skin 99. An electric nerve generator is connected to the anode and cathode probes on the electrical nerve stimulator 70. The electrical nerve stimulator is positioned over the electrode sensor and then manually moved to the desired location over the nerve. A display 230, 330 on the device 200 or 300, respectively, informs the healthcare worker the precise distance traveled. When the desired distance is achieved, the test is then performed.
The light emitter means 412 may be a light emitting diode which has small power consumption and high light intensity. The light emitted from the light emitter means 412 is reflected off the skin surface or incident to the rolling ball 440 disposed at the lower tip portion of the neck housing 405.
Connected to the light receiver 420 is a conversion and output unit 460 that converts the variations in the light sensed by the light receiver 420 into an electrical signal and outputs the electrical signal. That is, when the sensor 400 is moved over the skin surface, light emitted from the light emitter means 412 is reflected from the surface or rolling ball 440 having the lattice-shaped pattern 442 continuously varies and the conversion and output unit 460 converts the variations in the light sensed by the light receiver 420 into an electrical signal and then outputs the electrical signal.
A calculation unit 480 is disposed inside the nerve sensor 400 and calculates the real distance using the electrical signal input from the conversion and output unit 460. The calculator unit 480 is also electrically connected to a LCD display 500 that indicated the distance measured. The calculator unit 480 is electrically connected to an ON/OFF switch 510.
The input button unit 490 is disposed inside the neck housing 405 and inputs a signal to the calculation unit 480 indicating that the orifice 407 or rolling ball 440 is positioned at the first point A or the second point B.
During operation, the user grasps the body of the nerve stimulator 400 and holds in vertically upright. The tip of the neck housing 405 or the rolling ball 440 is placed on the first point A, the input button unit 490 is pressed to indicate to the calculation unit 480 that the present position of the rolling ball 440 is the first point A. Then the nerve stimulator 400 is moved over the nerve path so that the orifice 407 or rolling ball 440 remains in contact with the skin. As the nerve stimulator 400 is moved, the light emitted through the orifice 407 and reflected off the skin or incident on the rolling ball 420 is sensed by the light receiver 420. The variation in the light sensed by the light receiver 420 is converted into an electrical signal that is output to the calculation unit 440. The nerve stimulator 400 is moved to the second point B. Then, when the orifice 407 or rolling ball 480 reaches the second point B, the input button unit 490 is pressed to indicate to the calculation unit 480 that the present position of the housing 10 is the second point B. Then, the calculation unit 480 recognizes the second point B and calculates a distance over which the orifice 407 or rolling ball 420 has rolled from the first point A to the second point B. The distance is then shown on the display 500.
In compliance with the statute, the invention described herein has been described in language more or less specific as to structural features. It should be understood however, that the invention is not limited to the specific features shown, since the means and construction shown is comprised only of the preferred embodiments for putting the invention into effect. The invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the amended claims, appropriately interpreted in accordance with the doctrine of equivalents.
This is a continuation-in-part application based on U.S. patent application (Ser. No. 11/021,299) filed Dec. 23, 2004 and the provisional patent applications (Ser. No. 60/532,029) filed on Dec. 23, 2003, and (Ser. No. 60/541,511) filed on Feb. 3, 2004.
Number | Date | Country | |
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Parent | 11021299 | Dec 2004 | US |
Child | 12927508 | US |