Degradation of touch sensitivity is a common result of disease, injury and aging. However, the scientific understanding of the underlying neural mechanisms that cause these degradations is poorly understood. Quantitative monitoring of touch sensitivity over periods of time can provide valuable information for research on therapy and disease assessment. In addition, there are several diseases and conditions that selectively impair the motor system of the nervous system. Tremor and dystonia are a few motor impairments/abnormalities that result from disease, injury, and certain prescription medications. A better understanding of tremors, and earlier detection of low-level tremors, can improve patient outcomes.
In broad summary, herein are disclosed systems, apparatuses and methods for measuring tremors and peripheral nerve sensitivity. An apparatus can include a housing and an actuator and/or accelerometer accessible from an outer surface of the housing. An actuator can generate a stimulation signal to a skin surface of a subject. Processing circuitry can control the actuator to generate a stimulation signal, and record response to the stimulation signal to determine vibrotactile sensitivity. If an accelerometer is used, vibration generated by the subject can be measured. These and other aspects will be apparent from the detailed description below. In no event, however, should this broad summary be construed to limit the claimable subject matter, whether such subject matter is presented in claims in the application as initially filed or in claims that are amended or otherwise presented in prosecution.
In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limited sense, and the scope of the present invention is defined by the appended claims.
Haptic perception impairments and motor control abnormalities can be diagnosed and assessed in a clinical environment.
The subject 102 can provide feedback using a feedback device 114 acknowledging that the stimulus has been perceived. Feedback can be verbal, via computer screen button, touch screen button, dedicated button, keyboard, etc. The system 100 stores data (time of test, frequency and amplitude of stimulations, patient feedback, etc.), for analysis. This can be stored in the cloud 116, at the clinician device 110, or within the actuator assembly 106 itself, in a memory as described with respect to
The housing 300 can include a top piece 302 and a bottom piece 304 joined together, although embodiments are not limited thereto. Materials with resistance to cleaning chemicals can be used to construct the housing 300. Such materials can include one or more thermoplastic material types, such as polypropylene or acrylonitrile butadiene styrene (ABS), although embodiments are not limited thereto. Pieces (e.g., top piece 302 and bottom piece 304) should couple sufficiently to prevent water droplets from forming on internal electrical components when subjected to moderate spraying of cleaning solutions. A mechanism or apparatus (for example, an elastic strap or band, or an adhesive not shown in
The vibrotactile actuator 104 surface can be contoured for finger, hand or foot comfortable and repeatable placement. Vibration dampening in the form of ballast, sprung mass or shock absorptive mounts may be used to isolate the device from ambient vibration. The assembly 106 and/or housing 300 can be contoured to fit into or against, for example, the palm or other body part of the subject 102. The actuator 104 may induce vibration at the skin surface being stimulated. The vibration may be normal, or nearly normal to the skin surface although embodiments are not limited thereto. The actuator 104 may induce vibrations of known frequency, amplitude and phase through control using processing circuitry or other circuitry described later herein. The actuator 104 may comprise a piezoelectric disk (available from, for example, Steiner & Martins, Inc., of Dolan, Florida); voice coil; eccentric rotating mass (ERM) actuator (available from Precision Microdrives of London, England), or other type of actuator.
In some examples, gaps and seams in the housing 300 (
In examples, the mechanically compliant surface 500 facilitates transference of vibrations between the actuator 104 and a skin surface, digit, etc., of the subject 102. In some examples, the mechanically compliant surface 500 can be created by molding a thermoplastic urethane (TPU) or silicone membrane over the top of housing 300. In some embodiments, the mechanically compliant surface 500 can encompass the seam joining top piece 302 (
A separate piece of formed compliant material may be used to snap into recesses in the top of the housing 300 in some embodiments. In some embodiments, a flat piece of compliant material such as nitrile material may be clamped over the top of the actuator 104. A stiff piece of material may be used as a piston to transfer vibrations. In this case a separate mechanically complaint surface 500 could be used to insure the housing 300 stays resistant to water incursion.
An additional barrier to the spread of infection can include a disposable barrier between the subject and the actuator assembly. In aspects, these sterile barriers can be provided by a sterile dispensing system and disposed of after usage.
In addition to the components of an actuator assembly 106 already described herein, an actuator assembly 106 can include other components for providing control, communication, sensing, and other functionalities.
Referring to
The actuator assembly 106 can further include an accelerometer 802 to measure vibration. The accelerometer 802 can be a multi-axis accelerometer. An environmental sensor 804 can measure environmental vibration (building vibrations, bodily vibrations, etc.) or other vibrations distinct from the intended vibrotactile stimulus or patient tremor, and this can be used to mitigate the unwanted environmental vibrations by subtracting the vibration from the measured vibration of the actuator assembly 106. The actuator assembly 106 can further include a displacement sensor 806 to measure displacement of the mechanically compliant surface 500. The displacement sensor can be a laser displacement sensor. In some aspects, the displacement sensor can be a Doppler (LD) meter or sensor (for example, the Keyence LK-G5000 series Laser Displacement Sensor, available from Keyence of Itasca, Ill., USA).
The actuator assembly 106 can further include a memory, depicted and described in more detail later herein with reference to
The actuator assembly 106 can include other sensors and circuitry 808, including for example temperature sensors and humidity sensors, force sensors, and force control circuitry. Example temperature and humidity sensors can include sensors available from STMicroelectronics headquartered in Geneva, Switzerland. Example force sensors include FlexiForce sensors (available from TekScan of Boston, Mass.) or FX force sensors available from TE Connectivity headquartered in Schaffhausen, Switzerland. These and other sensors and control systems can provide analog or digital signals to the processing circuitry 800 using, for example any suitable bus such as universal serial bus (USB), I2C or SPI serial buses. Force control circuitry can control the force applied by the subject to the actuator.
The actuator assembly 106 can include communication circuitry 810. Communication circuitry 810 can be used to communicate over a wired or wireless interface 112 (
The actuator assembly 106 can include a battery 812, which can be rechargeable, or power can be provided by a connection such as through a power jack or USB port. The battery (if present) can be recharged through an internal charging circuit 814 inductively coupled at 816 to an external coil 818.
Referring again to
In the first (vibrotactile perception) mode the system 100 (or 200 for distributed system embodiments) determines the point at which a patient can detect a vibrotactile stimulus launched from the actuator assembly 106 and records patient perception. When taken over time changes in just-noticeable difference (JND) thresholds of perception can be quantified.
Such perception can occur at various receptors on the subject's body. There are four primary mechanoreceptors found in the glabrous (hairless) skin. Each of these mechanoreceptors respond to unique types of mechanical vibration. Each type of mechanoreceptor respects to different types of mechanical vibration, as shown in Table 1:
In methods according to at least some embodiments, processing circuitry 800 can control the actuator 104 (through commands issued by clinician device 110, for example) to sweep through various frequency ranges and determine the sensitivity of the patient to each vibrotactile frequency range. As measurements are taken over time, researchers can reach a greater understanding about the progression of peripheral neuropathy and how the different mechanoreceptors are impacted. Impact of drug therapy can also be observed. Methods for measuring vibrotactile perception and for detecting tremors are described below.
Method 900 begins with operation 902 with the processing circuitry 800 providing vibrotactile stimulation to an actuator in physical contact with a skin surface of a subject. In some embodiments, the vibrotactile stimulation is a single pulse.
In other embodiments, the vibrotactile stimulation includes a series of pulses based on standard benchmarks or protocols. In some embodiments, at least one pulse has a frequency of between about 0.4-100 Hz to stimulate Merkel's receptors. In some embodiments, at least one pulse of has a frequency of about 7 Hz to stimulate a Ruffini corpuscle. In some embodiments, at least one pulse has a frequency of about 10-200 Hertz to stimulate a Meissner's corpuscle. In some embodiments, at least one pulse has a frequency of about 40-800 Hertz. In some embodiments, a series of pulses includes pulses from more than one frequency range.
Method 900 continues with operation 904 with the processing circuitry 800 receiving an indication as to whether the stimulation was sensed. As described with respect to
Method 900 continues with operation 906 with the processing circuitry 800 analyzing the indication to diagnose a neurological disability. In some embodiments, the analyzing can include comparing recorded information over time to detect a change in vibrotactile perception. Further description of the analysis is provided later herein.
In some embodiments, when a distributed system such as system 200 (
Method 1000 begins with operation 1002 with providing an accelerometer (e.g., accelerometer 802 (
Method 1000 continues with operation 1004 with the processing circuitry 800 receiving a movement indication at the accelerometer 802.
Method 1000 continues with operation 1006 with the processing circuitry analyzing the indication to diagnose a neurological disability. In embodiments depicted according to
Analysis such as that performed in methods similar to methods 900 and 1000 can include correlation of tremor statistics to posture and physical activity may give provide diagnostic information for the clinician. For example, processing circuitry 800 can record tremor acceleration data and break this raw data into frames of data. The processing circuitry 800 can analyze each frame for frequency, frequency variation, and intensity. The processing circuitry 800 can also perform other statistical analysis including average frequency, frequency standard deviation or coefficient of variation, and intensity. For example, a resting tremor may be indicative of Parkinson's (frequencies between 4-8 Hz), and this resting tremor can have a first frequency spectrum that can be analyzed. In Parkinson's a resting tremor may be temporarily reduced during activity only to return (called a re-emergent tremor); this can have a separate indicative frequency spectrum, distinct from the frequency spectrum indicating a resting tremor. Dystonic tremors are irregular and jerky, which produce a different frequency spectrum than the consistent Parkinson tremor. Methods similar to those described earlier herein (particularly with reference to
The displacement of the mechanically compliant surface of an actuator assembly described earlier herein can be used for motor impairment assessment of physical phenomena other than tremors. For instance, subject 102 (
As mentioned earlier herein, especially during analysis and diagnosis of tremors, it can be important to account for environmental vibrations not related to tremors. Systems can be provided according to some embodiments to detect and account for such environmental vibrations.
A measure of vibration experienced by the patient (apatient) can be calculated by removing the environmental vibration (aenvironment) from that which is measured by an actuator assembly 106 or 206, noting as described above that apatient has an associated (x, y, z) reference coordinate system based on, for example, the direction of gravity, as well as an associated environmental vibration i.e., apatient=axyz−aenvironment. This is illustrated in
Signal processing and fusion may be used to signal process and enhance the various signal inputs for signal analysis. Examples of this processing and fusion may be signal averaging and application of frequency specific filters to remove, enhance the frequency content of the signal at block 1304. Signal analysis 1308 may include calculating the average frequency of tremor (found at block 1306). Variations in tremor frequency and intensity can also be determined. A report can be provided at 1310.
In some embodiments, processing circuitry 800 can calculate statics based on a tremor's data acquisition (e.g., based on axyz vs. T data, as input to block 1300 above). Alternately, this data could be shown graphically as discrete data points (a sequence of numbers) occurring at discrete time samples. This sequence of numbers is divided into data frames. In each frame the processing circuitry 800 can calculate tremor frequency or power compare the result across a number of frames. Alternately, the processing circuitry 800 can generate a moving filter that moves continuously from t=0 (or n=0) to the end of the data and calculate a sliding average tremor frequency. Techniques to do the above include Fourier, wavelet or other transform methods. The frame data is compared in with data from the same session or from days, months or years earlier to compare tremor statistics.
Computing Systems
Example computer system 1400 includes at least one processor 1402 (e.g., a central processing unit (CPU), a graphics processing unit (GPU) or both, processor cores, compute nodes, etc.), a main memory 1404 and a static memory 1406, which communicate with each other via a link 1408 (e.g., bus). The computer system 1400 can further include a video display unit 1410, an alphanumeric input device 1412 (e.g., a keyboard), and a user interface (UI) navigation device 1414 (e.g., a mouse). In one embodiment, the video display unit 1410, input device 1412 and UI navigation device 1414 are incorporated into a touch screen display. The computer system 1400 can additionally include a storage device 1416 (e.g., a drive unit), a signal generation device 1418 (e.g., a speaker), a network interface device 1420, and one or more sensors (not shown), such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor.
The storage device 1416 includes a non-transitory machine-readable medium 1422 on which is stored one or more sets of data structures and instructions 1424 (e.g., software) embodying or utilized by any one or more of the methodologies or functions described herein. The instructions 1424 can also reside, completely or at least partially, within the main memory 1404, static memory 1406, and/or within the processor 1402 during execution thereof by the computer system 1400, with the main memory 1404, static memory 1406, and the processor 1402 also constituting machine-readable media.
While the machine-readable medium 1422 is illustrated in an example embodiment to be a single medium, the term “machine-readable medium” can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more instructions 1424. The term “machine-readable medium” shall also be taken to include any tangible medium that is capable of storing, encoding or carrying instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure or that is capable of storing, encoding or carrying data structures utilized by or associated with such instructions. The term “machine-readable medium” shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media. Specific examples of machine-readable media include non-volatile memory, including, but not limited to, by way of example, semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and compact disc read-only memory (CD-ROM) and digital versatile disc-read-only memory (DVD-ROM) disks.
The instructions 1424 can further be transmitted or received over a communications network 1426 using a transmission medium via the network interface device 1420 utilizing any one of a number of well-known transfer protocols (e.g., hypertext transfer protocol (HTTP)). Examples of communication networks include a local area network (LAN), a wide area network (WAN), the Internet, mobile telephone networks, plain old telephone (POTS) networks, and wireless data networks (e.g., Wi-Fi, 3G, and 4G long term evolution (LTE)/LTE-Advanced (LTE-A) or WiMAX networks). The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the machine, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.
Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.
Filing Document | Filing Date | Country | Kind |
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PCT/IB2020/054579 | 5/14/2020 | WO | 00 |
Number | Date | Country | |
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62856459 | Jun 2019 | US |