Patent Application
20180014744
The present application relates to orthotics, and more specifically, to a motor-activated wrist orthotic to assist Individuals with Cervical Spinal Cord Injuries with activities of daily living.
There are approximately 12,500 new cases of Spinal cord injuries (SCI) every year in the United States alone. 53.9% of SCI are in the cervical region (C1-C7) and approximately 44% of these individuals have injuries in the C3-C6 region of the spinal cord (NSCISC, 2014). Daily manual activities such as unlocking doors with keys, holding utensils, writing, typing, using pointing devices, and swiping credit cards are extremely difficult for individuals with mid-cervical SCIs due to paralysis in the hand muscles preventing grasping and releasing and paralysis or weakness of wrist flexors and extensors. In order to stabilize a flaccid wrist, wrist orthoses or splints can be used to maintain the normal position of the hand and wrist. Wrist orthotics have often been used in rehabilitation of individuals with SCI to allow for the correct positioning of joints in the wrist, in order to maintain optimal muscle tone and structure. Tenodesis splints can be used for specific tasks such as assisting in picking up small objects by providing support to the thumb and forefinger. However, the limited motion of wrist braces for quadriplegics without the ability to flex or extend their wrists principally provides support. With the addition of a pocket in the palm strap, mid-cervical quadriplegics are able to insert dining utensils, pencils, pens, toothbrushes, or other tools to accomplish certain activities of daily living (ADL) independently.
For individuals with mid-level SCI (i.e. C4-05), common devices include surface Functional Electrical Stimulation (FES) systems in the form of a forearm sleeve which are applied during early rehabilitation to control voluntary wrist extension for grasping and flexion. Alternatively, several electromechanical exoskeletons have been constructed to provide basic support with hard metal hinges as manipulators. Most current systems assist individuals with SCIs through mechanical actuators or ratchet systems activated by existing functional muscles. The drawbacks of these devices are that they are bulky and cause fatigue to the individual. Common ways to control actuators on these systems include speech recognition and gesture recognition. Gesture recognition is often achieved through acceleration sensors or electromyography (EMG) signals. Unfortunately, EMG and accelerometer signals by themselves tend to be very noisy and can often lead to false positives. While improvements in speech recognition technology provide accurate control of actions during steady state, performance is significantly reduced in noisy environments. Therefore, improvements are needed in the field.
According to one aspect, the present disclosure provides a wearable multifunctional wrist orthotic (MFWO) which is activated by the user's limited motor function including EMG signals from the pronator teris (wrist muscle) and customized switch activation methods and concurrently performs distinct functions based on the recognition of different individualized gestures through an Inertial Measurement Unit (IMU). The microcontroller unit may be configured to perform two-tiered gesture recognition. The first tier comprises a fine gesture sensed by the EMG sensor and the second tier comprises a gross gesture sensed by the IMU sensor.
According to another aspect, a wrist orthotic is provided, comprising a rigid housing formed to fit around a portion of a forearm, wrist, and a portion of a hand of a user, a plurality of flexible straps for securing the housing to the user, an electromyography (EMG) sensor mounted to the housing and having at least two electrodes for attachment to the wrist of the user, an interial measurement unit (IMU) mounted to the housing, a microcontroller unit mounted to the housing and connected to the IMU, and a power supply unit mounted to the housing. The microcontroller may operate a device connected to the orthotic, such as an actuatable device, in response to recognized gestures.
In the following description and drawings, identical reference numerals have been used, where possible, to designate identical features that are common to the drawings.
The attached drawings are for purposes of illustration and are not necessarily to scale
In the following description, some aspects will be described in terms that would ordinarily be implemented as software programs. Those skilled in the art will readily recognize that the equivalent of such software can also be constructed in hardware, firmware, or micro-code. Because data-manipulation algorithms and systems are well known, the present description will be directed in particular to algorithms and systems forming part of, or cooperating more directly with, systems and methods described herein. Other aspects of such algorithms and systems, and hardware or software for producing and otherwise processing the signals involved therewith, not specifically shown or described herein, are selected from such systems, algorithms, components, and elements known in the art. Given the systems and methods as described herein, software not specifically shown, suggested, or described herein that is useful for implementation of any aspect is conventional and within the ordinary skill in such arts.
As shown in
The wrist orthotic of
The EMG sensor 106 may comprise a light-weight sensor which measures action potentials from adhesive surface electrodes placed on top of the pronator teris (wrist muscle) of the user. The sensor 106 identifies a pattern of rapid supination-pronation of the wrist by the orthotic wearer, which then allows for appropriate activation of the IMU 110 during a preset time period. A touch-activated sensor may comprise a switch which is activated by contacting another surface in a specific position or providing close proximity to other body parts. To improve the accuracy of the gesture recognition, a dynamic time warping (DTW) based machine learning process is implemented by the microcontroller 112 in certain embodiments. The DTW process two time dependent sequences and identifies the similarities in them. In certain embodiments, after sensing a fine gesture from the EMG sensor 106, the IMU 110 recognizes four distinct gross gestures—In-Out, Out-In, In-Hold and Out-Hold, as shown in
The microcontroller 112, sensors 106 and 110, and other components recited herein may include one or more computer processors and memory which are communicatively connected and programmed to perform the data processing and control functionality recited herein. The program code includes computer program instructions that can be loaded into the processor, and that, when loaded into processor cause functions, acts, or operational steps of various aspects herein to be performed by the processor. Computer program code for carrying out operations for various aspects described herein can be written in any combination of one or more programming language(s), and can be loaded into memory for execution. The processors and memory may further be communicatively connected to external devices via a wired or wireless computer network for sending and receiving data.
The invention is inclusive of combinations of the aspects described herein. References to “a particular aspect” and the like refer to features that are present in at least one aspect of the invention. Separate references to “an aspect” (or “embodiment”) or “particular aspects” or the like do not necessarily refer to the same aspect or aspects; however, such aspects are not mutually exclusive, unless so indicated or as are readily apparent to one of skill in the art. The use of singular or plural in referring to “method” or “methods” and the like is not limiting. The word “or” is used in this disclosure in a non-exclusive sense, unless otherwise explicitly noted.
The invention has been described in detail with particular reference to certain preferred aspects thereof, but it will be understood that variations, combinations, and modifications can be effected by a person of ordinary skill in the art within the spirit and scope of the invention.
The present application is related to and claims the priority benefit of U.S. Provisional Patent Application Ser. No. 62/362,011, filed Jul. 13, 2016, the contents of which are hereby incorporated by reference in their entirety into this disclosure.
| Number | Date | Country | |
|---|---|---|---|
| 62362011 | Jul 2016 | US |
