Patent Application
20080154156
Neurosensory injuries and surgical procedures to extremities, such as hands and feet, are a challenge to medical professionals in determining initial damage to nerves and recovery progress of the nerves. One way for diagnosing initial nerve damage and nerve recovery is to apply stimulation to points on a hand, such as fingers or palm, or foot, such as toes or sole. The stimulation that is typically applied for testing nerve function includes pressure, temperature, and/or electrical current, for example. One stimulation test that is often performed includes applying stimulation, such as pressure, from two nearby points. The purpose of the test is to determine the innervation density of the patient's fiber-receptor system in the area being tested.
There are generally two tests for determining innervation density, including dynamic and static testing. A dynamic pressure test (i.e., moving two points along the surface of the skin) assesses response of the quickly adapting fiber-receptor system. Dynamic tests are typically used to determine neurosensory functions requiring moving touch, such as object identification (e.g., buttoning a button). A static pressure test is typically used for determining neurosensory functions requiring pressure sensing, such as shaking a hand.
Another test that is often used includes a two-point discrimination test. A two-point discrimination test is performed by pressing two points against a portion of a person's skin and determining whether the person can sense both points. The two-point discrimination test is used for testing the slowly adapting fiber-receptor system. This is a static test and can be used to assess hand functions requiring a sensory grip and constant touch, such as holding tools, pencils or the like.
It has been well known to provide one or two-point discrimination tests. One device known as the DISK-CRIMINATOR® has been advanced, and it includes an octagonal disk that has a series of metal rods or prongs protruding from the periphery at different spacings (e.g., 2 mm-8 mm and 9 mm-16 mm). In operation, a patient may press one or two adjacent rods or prongs onto a test point for two-point discrimination testing. The use of such a device for testing is imprecise and subjective as the test giver is generally a medical professional or patient who is self-administering the test who “estimates” the amount of pressure exerted on the patient's skin. Therefore, there is a need for a more precise and less subjective two-point discriminating testing device to enable medical professionals and patients determine the healing progress of neurosensory injuries.
In an embodiment of the present invention, a load sensing cell is disclosed that includes a pair of substantially planar walls that are in substantially parallel relation to each other. The load sensing cell also includes a pair of interconnect side walls, each of which is connected to and extends between the pair of substantially planar walls. The load sensing cell further includes a strain gauge connected to at least one of the pair of planar walls in a manner that produces signals related to bending of the substantially planar walls in directions transverse to their planes. The load sensing cell is configured such that bending loads may be applied to the load sensing cell in directions substantially transverse to the planes of the substantially planar walls.
In another embodiment of the present invention, a device for determining nerve function response is disclosed that includes a first flexible beam and a second flexible beam. The second flexible beam is disposed outwardly from and is substantially parallel to the first flexible beam. The device also includes an interconnect in contact with the first flexible beam and the second flexible beam, wherein the first flexible beam is operable to be flexed in response to a load applied to the flexible beam.
In yet another embodiment of the present invention, a sensing device with a dual beam structure is disclosed for sensing human nerve function.
In a further embodiment of the present invention, a method of determining nerve function response is disclosed that includes measuring a flexure of a dual beam, the degree of flexure being related to nerve function response.
In an additional embodiment of the present invention, a device for determining nerve function response is disclosed that includes a dual beam and at least one sensor disposed on the dual beam operable to detect the flexure of the dual beam. The device also includes a processor operable to convert first data related to the degree of flexure of the dual beam into second data related nerve function response, such as sensibility.
Another embodiment may include a system for managing neurosensory test information. The system may include a neurosensory test apparatus configured to make at least one neurosensory test data reading from a patient. A computing system may operate on a network and be in communication with a storage unit. A data repository may be stored in the storage unit and be configured to store neurosensory test data read by the neurosensory test apparatus. Means for communicating the neurosensory test data to the data repository maybe utilized.
Still yet, the principles of the present invention may provide for an apparatus for testing a neurosensory response from a patient. The apparatus may include a handheld computing device including a user interface, sensing electronics electrically connected to the handheld computing device, a housing configured to house the sensing electronics and support the handheld computing device, where the housing may further be configured to enable a user to access the user interface of the handheld computing device, and a neurosensory sensory device, operable to test a neurosensory response from a patient, in communication with the handheld computing device.
The present invention relates to an apparatus used to sense human patient nerve function. In one embodiment, the apparatus is portable for ease of transport and use between test centers and other locations. Reference to a “test center” means a hospital doctor's office, rehabilitation facility, clinic or other facility or organization that will test patients, particularly for nerve health. In addition, a device being “portable” means that the device is easily moveable from a test center to another location, and easily moveable within the test center from one patient to another.
More particularly, dual beam structure 100 includes a beam 110 and a beam 120. Beam 110 and 120 are connected by interconnect 130. Beam 110 and beam 120, although described as separate beams, may be separate structures or two walls, arms, or other portions of a single structure. Such beams maybe constructed in such a manner so that thickness 112 and thickness 122 are small enough to flex in response to very small forces or pressures applied to either beam 110, beam 120, or another structure attached or coupled thereto or otherwise allowing the communication of force thereto. More particularly, thickness 112 and thickness 122 may be determined in response to the type of material used to construct beam 110 or beam 120. Thickness 112 and thickness 122 may also be determined based on the level of sensitivity desired for a device used to evaluate nerve function. In one embodiment, thickness 112 and thickness 122 are similar, and may even be substantially the same thickness. For example, in one embodiment, thickness 112 and thickness 122 may each be less than 0.0001 of an inch. In another embodiment, thickness 112 and thickness 122 may each be less than 0.0005 of an inch. Testing has been conducted of dual beam structure 100 with thicknesses 112 and 122 of approximately 0.0004 of an inch that show substantially significant increases in sensitivity when used in a device for determining nerve function sensibility.
Those of skill in the art will appreciate that beams 110 and 120 may be made from a variety of materials (such as metal or polymer) depending on the intended load to be applied to such beams 110 and 120 and the desired sensitivity of beams 110 and 120. For example, in one embodiment beam 110 and beam 120 are formed of titanium. Alternatively, beam 110 and 120 maybe formed of aluminum or stainless steel.
As illustrated in
Interconnect 130 maybe any connection between beam 110 and beam 120. For example, in the illustrated embodiment, interconnect 130 is a sidewall of a single machined piece of metal that connects planar surfaces of such metal that form beam 110 and beam 120. Although interconnect 130 is illustrated as being proximate to the end of dual beam structure 100 and therefore the end of beam 110 and 120, interconnect 130 may alternatively be located elsewhere along the interior planar surfaces or edges of beam 110 and beam 120. Although illustrated as a single sidewall, interconnect 130 may include one or more interconnecting elements or surfaces between beam 110 and beam 120. Also, interconnect 130 may be deemed to include other portions of dual beam structure 100. For example, as illustrated in
Base 125 is a portion of dual beam structure 100 used to mount dual beam structure 100 to other portions of a sensory device. Base 125 may include aperture 150, a plurality of apertures 160, and an aperture 170. Apertures 160 may include holes used to enclose guide members to allow the lateral movement of dual beam structure 100 along a sensory device such as sensory device 200 described below relative to
Dual beam structure 100 may be generally referred to as a load sensing cell. Beam 110 and beam 120 may be substantially planar walls that are in substantially parallel relation to each other. Interconnect 130 and the side of base 125 proximate to beams 110 and 120 may form a pair of interconnect sidewalls, each of which is connected to and extends between beam 110 and beam 120. Thus, sensors 180 may be strain gauges connected to one or more of beams 110 and 120 in a manner that changes resistance, produces signals, or otherwise changes the properties of beams 110 or 120 in response to a bending of beams 110 or 120 in directions transverse to their planes. Thus, the load sensing cell that is dual beam structure 100 may be configured such that bending loads applied to the load sensing cell and in a direction substantially transverse to the planes of the substantially planar walls forming beams 110 and 120 are detectable. Dual beam structure 100 may include a support member such as base 125 that is configured to engage a support structure in a manner that enables the load sensing cell to be mounted on the support structure in cantilever fashion.
Dual beam structure 100 also includes one or more sensors 180. Sensors 180 may be disposed on beam 110 and/or beam 120. In one embodiment, sensors 180 are strain gauges that detect the bending or flexing of beam 110 or beam 120. However, sensors 180 may be any suitable sensors whether electrical, electromechanical, optical, molecular, or any other type of sensor suitable for detecting a change in the properties or characteristics of beam 110 or beam 120 that may be indicative of the flexing, bending, or other changes in beams 110 and 120. Although described as separate sensors 180, sensors 180 may not be separate sensors or devices and may instead be resistive elements formed as part of dual beam structure 100. For example, the electrical properties of a particular region of dual beam structure 100 may be changed through the doping or deposition of additional chemicals or elements or molecular sized particles to create resistive devices out of the portions of dual beam structure 100 themselves.
Sensory device 200 may also include guide members 250. As previously described relative to
Although all of the components and portions of sensory device 200 are not explained herein in exact detail, both the illustrations of
The use of interconnect 330 is important because it allows for a decreased thickness of beams 310 and 320. Without interconnect 330, beams 310 and 320 would not have enough robustness and would be vulnerable to deformation and other damage impacting its ability to correctly sense a load applied to the end of probe 345. Indeed, without interconnect 330, it is likely that a single beam structure would need to be utilized with such single beam structure having a greater thickness than either beam 310 or beam 320. However, using the dual beam structure 305 of sensory device 300 and interconnect 330 as a portion thereof, the thickness of beams 310 and 320 may be reduced, resulting in greater sensitivity to a load applied to the end of probe 345 that will result in the flexing of beams 310 and 320.
Although probe 345 is illustrated as a curved prong, probe 345 may be any suitable prong, pin, needle, beam, button, or any other suitable component to which pressure or a force may be applied. In one embodiment, probe 345 may be manufactured as an integral part of a single machined material with dual beam structure 305 such that probe 345 is merely an extension of one or more surfaces of dual beam structure 305.
In one embodiment, sensors 410 includes resistive elements arranged in a wheatstone bridge configuration as illustrated relative to resistive elements S1, S2, S3, and S4. Such resistive elements, for example, may be part of one or more strain gauges deployed on dual beam structure 100 or may instead be resistance inherent in the material of dual beam structure 100. Voltage generator 420 is a voltage source utilized to apply a voltage signal to sensors 410. For example, generator 420 may provide a voltage signal between the junctions of resistive elements S1 and S2 and S3 and S4.
In such a manner, a voltage output at each of the junctions between resistive elements S1 and S3 and resistive elements S2 and S4 may be compared utilizing differential amplifier 430. The output of differential amplifier 430 may be sampled at particular intervals by sample and hold circuit 440 and held. The output of sample-and-hold circuit 440 is representative of the differential voltage applied across the input terminals of differential amplifier 430, which is in turn representative of the change in resistance across resistive elements S1, S2, S3, and S4, which is in turn representative of the degree to which a beam such as beam 110 of
The output of sample-and-hold circuit for 40 is in turn converted from an analog signal to a digital signal that remains indicative of the initial flexing of a beam, such as beam 110 of
The PDA module 606 may interface with the sensory device 300 of
In addition to the PDA being able to test patients, the PDA module 606 may enable a user to look up, sort, and/or generate statistics of one or more patients. Historical information for a patient may be looked up and presented to a user of the PDA in tabular or graphical formats, for example. In addition, the PDA module 606 may aggregate statistics of multiple patients having a common injury or other relation (e.g., age). The aggregated statistics may be displayed to the user in a tabular or graphical format. For example, the PDA module 606 may enable a user to look up all users with a similar injury to an ulna nerve and generate a graph showing sensory recovery over time. Such generalized information may be valuable to medical professional professionals and patients seeking to determine typical recovery times of certain injuries.
Further, the PDA module 606 may enable a user to calibrate the sensory device 300 by stepping a person through a number of steps to use calibration equipment, such as a device configured to apply calibrated pressure to one or more probes of the sensory device 300. In operation, the PDA module 606 may be set into a read mode for reading output signals in response to a calibrated pressure being applied to the sensory device 300. The output signals may be a continuous stream of signals from a sample and hold circuit within the sensory device 300 or a signal indicative of the maximum force measured by the sensory device 300. Based on the measurements from the sensory device 300, the PDA module 606 may enable the user to apply an offset to cause the PDA module 606 to account for any difference between the calibration equipment and the readings by the sensory device 300. The offset may be stored by the PDA module 606 to offset measurements during patient testing. The offset may also be read by the host module 606 to monitor operation of sensory devices 300 over time.
The host module 606 is utilized to manage a patient test database and provide capabilities to process test data and produce detailed and historic test reports for medical professionals to review. The host module 606 may be configured to provide a user interface, such as a graphical user interface (GUI), for a user to perform various operations. The host module 606 may be executed on a personal computer (PC). In one embodiment, the host module 606 may enable a user to upload the neurosensory test data collected by the PDA module 606. The host module 606 may synchronize a host database with the patients currently stored on the PDA. For example, if information of a new patient is entered into the host database via the host module 606, new patient information may be downloaded to the PDA automatically or manually. For example, at the start of each day, a medical professional (e.g., physical therapist) may utilized the host module 606 to establish the patients coming in for testing that day and the host module 606 may download the records of the patients to the PDA. The host module 606 may store the neurosensory test data in a database or other data repository locally or remotely. Further, the host module 606 may be utilized to produce reports of individual patients or aggregate data of multiple patients in the same or similar manner as described with respect to the PDA module 606. It should be understood that the host module 606 may be HIPAA compliant and aggregate patient data without disclosing information specific to any patient.
The web interface module 608 may provide for one or more central databases. In one embodiment, one database may operate as an authorization database. The authorization database maybe updated to specify which test units are authorized for continued use. As shown in TABLE I below, the authorization database may include parameters, including Authorized PDA's, Serial No., User Name, User ID, and User Password Other parameters associated with the PDA's or authorized users may be included in the authorization database. A second database may be a patient test database that is updated from sensory units that are used by medical professionals on patients. The second database may include a number of different non-test parameters, including Patient Name, Patient No., and Injury. Neurosensory test information, such as test date, measurement, and notes, may be stored in the database. The measurement may be the maximum pressure measurement taken from the patient during the neurosensory test. In one embodiment, sensitivity of the sensory device ranges between 0.2 and 100 grams per square millimeter (g/mm2) for pressure, 2 mm-20 mm for distance, and sensitivity (i.e., accuracy) is 0.01 g/mm2. If a pressure measurement is above 100 g/mm2, it is determined that nerve fibers are dead and the sensory device may store or print out, “no one point static” or “no two point static touch,” for example. It should be understood that the sensitivity pressure ranges using the sensory device 300 is due to the strain gage bridge being split across two thin beams, as more fully described hereinabove. Other test information, such as the precise location on the patient's body of the test, may be stored in the database. Because the test database includes measurement data taken over a period of time, a doctor or other medical professional can plot the results over time on a graph and determine the progress of the patient.
The web interface module 608 may additionally provide for updating software in the host module 606 and PDA module 604. In addition to provide for database management, the web interface module 608 may be utilized to enable a user to view test data and generate reports from the test data. The web interface module 608 may enable a user to perform statistical analysis on the test data in an aggregate manner compliant with the Health Insurance Portability and Accountability Act of 1996 (HIPAA) rules.
Personal computers (PC's) 720a-720n (collectively 720) may be in communication with the network 718. The PC's 720 may operate as host computers that are in communication with the network 718. When a medical professional desires to upload the test data taken from patients, the memory card 722 may be removed from the PDA 716z and inserted in the PC 720a or adapter connected thereto. Data stored on the memory card 722 may be read by software, such as the host module 606, and uploaded onto a database being stored on the PC 720a. Alternatively and/or additionally, the test data may be uploaded to the database 714 at the server 702. The PC's 720 may be utilized to interact with the databases 714 to access data of particular patients, generate statistical analysis, and view reports of aggregated test data. In one embodiment, the server 720 is a personal computing device configured to operate as a server. The software 706 may operate the web interface module 608, the host PC's 720 may operate the host module 606, and the PDA's 716 may operate the PDA module 604.
As further illustrated in
As described, the housing 900 may be configured to support a wide range of handheld computing device configurations. Through the use of the cradle 906 and bezel 908, virtually any Windows CE based handheld computing device may be accommodated without change to the case design. To protect the electronics and handheld computing device 902, the top cover and other surrounding structure (e.g., cradle 906 and bezel 908) may be formed of plastic, aluminum, or any other material that protects the internal data acquisition hardware, power supply and handheld computing device 902 to perform sensory tests.
Utilization of the sensory device and other principles of the present invention provide the ability to measure dynamic changes (i.e., one and two-point moving touch), which was heretofore not possible. The sensory device permits the evaluation of nerve regeneration because the one-point moving touch recovers before one-point static touch and two-point moving touch recovers before two-point static touch.
Although particular embodiments of the present invention have been explained in detail, it should be understood that various changes, substitutions, and alterations can be made to such embodiments without departing from the spirit and scope of the present invention as defined solely by the following claims.
