A Smart Strap includes a flexible strap having a first plurality of vibration actuators, a second plurality of vibration actuators, and a motion sensor, with a processor having a processor power source connected to the motion sensor. An actuator power source is connected to the two pluralities of vibration actuators through a first switch and a second switch, respectively. The processor is configured to read acceleration of the motion sensor at a prescribed frequency, and turn on the first plurality of vibration actuators for a first prescribed treatment time when the acceleration exceeds a threshold acceleration value for a threshold time period. The processor is further configured to turn on the second plurality of vibration actuators when the acceleration remains above the threshold acceleration value after the first plurality of vibration actuators are turned on. The processor is configured to transmit an event record to a recording device.

FIELD

This disclosure relates to the field of therapeutic devices for tremors. More particularly, but not exclusively, this disclosure relates to wearable therapeutic devices for tremors.

BACKGROUND

Tremors may adversely impact patients' lifestyles and impair their ability to perform simple daily tasks. One cause of tremors is Parkinson's disease, which is a progressive, neurodegenerative disease. In the United States alone, there are 1 million people who have Parkinson's disease. In addition, there are an estimated 10 million people worldwide who have the disease. There is no known cure for Parkinson's disease. Movement control is accomplished by complex interactions among various groups of nerve cells in the central nervous system, and one of those critical cells helping to produce the hormone dopamine. Dopamine is a neurotransmitter responsible for relaying messages that plan and control body movement. When dopamine levels decrease in the brain, tremors begin taking a toll on the body, limiting movement control. There are very few treatments that mitigate the symptoms. Stem cell therapies, gene therapies, and growth factors have all been tried, to compensate for the lack of dopamine; their positive effects are minimal and cost thousands of dollars per therapy treatment. Whole-body vibration therapy has been a recent topic of interest as many new studies have shown the treatment to have temporary positive effects on the tremors. However, it is expensive and not easily accessible.

SUMMARY

The present disclosure introduces a vibration-induced tremor relief apparatus, hereinafter the Smart Strap, including a flexible strap having vibration actuators and a motion sensor, for attaching to a patient. The Smart Strap includes a processor electrically coupled to the motion sensor, and at least one switch to control power to the vibration actuators. The processor is configured to control the switches. The Smart Strap also includes a processor power source connected to the processor, and an actuator power source electrically coupled to the vibration actuators through the switches. The processor is configured to read acceleration of the motion sensor at prescribed frequency, turn on a first switch when the acceleration of the motion sensor exceeds a threshold acceleration value for a threshold time period, causing a first plurality of the vibration actuators to turn on for a first prescribed treatment time period. The processor may be further configured to increase an intensity of the vibration actuators when the acceleration of the motion sensor remains above the threshold acceleration value by turning on a second switch, causing a second plurality of the vibration actuators to turn on for a second prescribed treatment time period. The processor transmits an event record to a recording device. A method of treating tremors using the Smart Strap is disclosed.

DETAILED DESCRIPTION

A Smart Strap includes a flexible strap with vibration actuators and a motion sensor. A processor is electrically coupled to the motion sensor, and is configured to read acceleration of the motion sensor at prescribed frequency. The vibration actuators are coupled to a power source through at least one switch that is controlled by the processor. When the acceleration of the motion sensor exceeds a threshold acceleration value for a threshold time period, the processor turns on a first switch, causing a first set of the vibration actuators to turn on for a first prescribed treatment time period. Optionally, when acceleration of the motion sensor remains above the threshold acceleration value, the processor turns on a second switch, causing a second set of the vibration actuators to turn on for a second prescribed treatment time period. The processor transmits an event record to a recording device for each excursion of the acceleration above the threshold acceleration value.

FIG.1depicts an example Smart Strap. The Smart Strap100includes a flexible strap102that is sufficiently long to extend around a patient's wrist or ankle. The flexible strap102may be 8 inches to 12 inches long, for example. The flexible strap102may include fabric and/or flexible sheet material. The flexible strap102has an attaching structure104on a first end of the flexible strap102configured to attach to a second end106of the flexible strap102, opposite from the first end. The attaching structure104may be manifested as a hook-and-loop patch, a buckle, a magnet, one or more buttons, one or more snaps, or a zipper, for example.

The Smart Strap100includes a first plurality of vibration actuators108aand may include a second set of vibration actuators108battached to the flexible strap102. The first plurality of vibration actuators108amay include 5 to 20 of the vibration actuators108aand the second plurality of vibration actuators108bmay include 5 to 20 of the vibration actuators108b, which has been demonstrated to be effective in reducing tremor levels in patients using the Smart Strap100. The vibration actuators108aand108bare operable to vibrate at 30 cycles per second to 300 cycles per second when electrical power is applied to the vibration actuators108aand108b. The vibration actuators108aand108bmay be manifested as coin motors, also known as Eccentric Rotating Mass (ERM) motors, or Linear Resonant Actuators (LRAs), for example. Other manifestations of the vibration actuators108aand108bare within the scope of this example. The vibration actuators108aand108bmay be attached to the flexible strap102by hook-and-loop tabs, thread or wire, adhesive, clips, or other attachment means. The vibration actuators108aand108bmay be enclosed in the flexible strap102in fabric pockets, or may be exposed on one side or both sides of the flexible strap102.

The Smart Strap100includes a motion sensor110attached to the flexible strap102. The motion sensor110may be manifested as a 3-axis MEMS accelerometer, configured to measure acceleration in three orthogonal directions, for example. The motion sensor110may be configured to measure acceleration from less than 0.1 g to greater than 10 g, where g is the acceleration due to gravity at the earth's surface. For the purposes of this disclosure, g is taken to have a value of 9.8 meters/second2, for the purpose of setting the threshold acceleration value.

The Smart Strap100includes a processor112that is configured to read acceleration of the motion sensor110and is configured to control the vibration actuators108aand108b. In this example, the processor112may be manifested as a Raspberry Pi 3 B microcontroller, available from the Raspberry Pi Foundation. The processor112includes a system on chip114which has a 64 bit 1.2 GHZ Quad Core ARM V8 central processing unit (CPU) and a graphics processing unit (GPU). The processor112includes a random access memory (RAM)116, containing volatile memory, and a secure digital (SD) card118, containing non-volatile memory, both located on a side of the processor112opposite from the system on chip114. The processor112includes wireless communication capability, which enables communication over WiFi and Bluetooth channels. The processor112also includes network and universal serial bus (USB) controller capability. The processor112further includes USB ports120and an Ethernet port122which enable communication to the system on chip114. The processor112includes a general purpose input/output (GPIO) port124having 40 pins for input and output of digital and analog signals. The motion sensor110is electronically coupled to the pins of the GPIO port124, as indicated schematically inFIG.1, to provide power to the motion sensor110and read data from the motion sensor110.

The processor112includes two ports for power input: a micro USB port126and a power-over-Ethernet header128. The processor112may be powered through either of these two ports. When using the power-over-Ethernet header128, voltage on the Ethernet line is commonly 48 volts, and must be stepped down to approximately 5 volts for active components of the processor112.

The Smart Strap100includes a processor power source130, which may be manifested as a rechargeable battery, a battery pack, a super capacitor, or a fuel cell, for example. The processor power source130is electrically connected to the processor112, so as to provide power. In this example, the processor power source130may be electrically connected to the processor112through the micro USB port126, as indicated schematically inFIG.1.

The Smart Strap100includes an actuator power source132which provides power for the vibration actuators108aand108b. The actuator power source132may be manifested as a battery pack, as depicted inFIG.1, a rechargeable battery, a super capacitor, or a fuel cell, for example. The Smart Strap100includes a first relay134awhich is controlled by the processor112and which electrically couples the actuator power source132to the first plurality of vibration actuators108a, as indicated schematically inFIG.1. The Smart Strap100may optionally include a second relay134bwhich is controlled by the processor112and which electrically couples the actuator power source132to the second plurality of vibration actuators108b, as indicated schematically inFIG.1. Coupling the actuator power source132to the vibration actuators108aand108bthrough the relays134aand134benables more power to be provided to the vibration actuators108aand108bthan powering the vibration actuators108aand108bdirectly by the processor112. Voltage and control terminals of the relays134aand134bare electrically connected to the pins of the GPIO port124, as indicated schematically inFIG.1. During operation of the Smart Strap100, the processor112provides 12 volts and ground potentials to the relays134aand134bto make the relays134aand134bfunctional. The processor112is configured to provide first and second trigger signals, at 3.3 volt to 5 volts, to the relays134aand134b, to close the relays134aand134band provide power to the vibration actuators108aand108bfrom the actuator power source132.

During operation of the Smart Strap100, the processor112communicates with a recording device136, shown inFIG.1, over a WiFi or Bluetooth channel. The recording device136may be implemented as a cellular phone, as depicted inFIG.1, a smart watch appliance worn by a patient using the Smart Strap100, or a stationary appliance such as a personal computer, by way of example.

FIG.2depicts the Smart Strap in use on a wrist of a patient. The flexible strap102is wrapped around the wrist of the patient138and secured by attaching the attaching structure104ofFIG.1to the second end106of the flexible strap102. The processor112, the processor power source130, and the relays134aand134bmay be located in a container140for convenience. The container140may be implemented as a clamshell case, a handbag, or a pouch secured to the patient138, by way of example. The recording device136is maintained within communication range of the processor112, to enable reception of an event record transmitted by the processor112. In versions of this example, the recording device136may be stored in the container140. Having the flexible strap102around the wrist of the patient138may advantageously assist with hand activities, such as writing and manipulating objects, by the patient when experiencing tremors.

FIG.3depicts the Smart Strap in use on an ankle of a patient. The flexible strap102is wrapped around the ankle of the patient138and secured by attaching the attaching structure104ofFIG.1to the second end106of the flexible strap102. The processor112, the processor power source130, and the relays134aand134bmay be located in the container140and carried by the patient. The recording device136may be carried by the patient in a pocket, worn on a writs, or stored in the container140, by way of example. Having the flexible strap102around the ankle of the patient138may advantageously assist the patient with walking, when experiencing tremors, a condition known as “gait freeze”.

FIG.4is a flowchart of an example method of treating tremors using the Smart Strap100ofFIG.1. During the method400, a patient wraps the Smart Strap around their wrist or ankle and turns on the processor112. The method400begins with step402, in which values of the acceleration of the motion sensor110ofFIG.1are read by the processor112at a prescribed frequency. The prescribed frequency may be 4 Hertz (Hz) to 10 Hz, by way of example. Hertz is a unit of frequency; 1 Hz equals 1 per second. Research on symptoms of Parkinson's disease has indicated that tremors in patients tend to occur at 4 Hz to 5 Hz, so reading the acceleration at 4 Hz to 10 Hz characterizes patient movements sufficiently to detect tremors in the user.

After each reading of the acceleration in step402, step404is executed, which includes determining if the acceleration has been above a threshold acceleration value for every acceleration reading in a threshold time period. The threshold acceleration value is selected to discriminate normal motions from tremors. Tests performed in development of the Smart Strap100have shown a threshold acceleration value of 1.6 g to 2.3 g is effective in discriminating normal motions from tremors, as discussed in reference toFIG.12. The threshold time period is selected to discriminate transient motions from tremors. A threshold time period of 1.5 seconds to 3 seconds has been demonstrated to be effective in discriminating transient motions from tremors.

In one version of the method400, values of recent acceleration values may be stored in the RAM116ofFIG.1, and recalled during execution of step404to determine if the acceleration has been above the threshold acceleration value for the threshold time period. In another version of the method400, Boolean values TRUE and FALSE corresponding to recent acceleration values, in which a TRUE value indicates the acceleration value exceeds the threshold acceleration value and a FALSE value indicates the acceleration value does not exceed the threshold acceleration value, may be stored, and recalled during execution of step404to determine if the acceleration has been above the threshold acceleration value for the threshold time period. Other methods of determining if the acceleration has been above the threshold acceleration value for the threshold time period are within the scope of step404.

If the result of step404is TRUE, that is, the acceleration has been above the threshold acceleration value for the threshold time period, execution of the method400branches to step406. If the result of step404is FALSE, that is, the acceleration has not been above the threshold acceleration value for the threshold time period, execution of the method400branches back to step402.

Step406includes activating the first plurality of vibration actuators108aofFIG.1for a first prescribed treatment time. The processor112turns on the first relay134aby applying a first trigger signal of 3.3 volts to 5 volts to the first relay134a. Applying the first trigger signal causes the first relay134ato close and provide power from the processor power source130to the first plurality of vibration actuators108a. Providing power to the first plurality of vibration actuators108acauses the first plurality of vibration actuators108ato vibrate at 30 cycles per second to 300 cycles per second. The vibration may advantageously disrupt the tremors in the patient, enabling more normal functioning for the patient. The processor112maintains the first trigger signal to the first relay134afor the first prescribed treatment time. Tests performed in development of the Smart Strap100have shown a first prescribed treatment time of 30 seconds to 5 minutes is effective in reducing the tremors.

After the processor112applies the first trigger signal to the first relay134a, step408is executed, in which subsequent values of the acceleration of the motion sensor110are read by the processor112at the prescribed frequency, to determine if the acceleration is reduced below the threshold acceleration value. In one version of this method400, the processor112may assess the acceleration while the first plurality of vibration actuators108aare still activated. For example, the processor112may assess the acceleration midway in the first prescribed treatment time. In another version of this method400, the processor112may assess the acceleration after the first prescribed treatment time has elapsed. If the result of step408is FALSE, that is, the acceleration remains above the threshold acceleration value, execution of the method400branches to step410. If the result of step408is TRUE, that is, the acceleration is reduced below the threshold acceleration value, execution of the method400branches to step412.

Step410includes activating the first and second pluralities of vibration actuators108aand108bofFIG.1for a second prescribed treatment time. In the version of this method400in which the processor112assesses the acceleration while the first plurality of vibration actuators108aare still activated, the first trigger signal is maintained for the execution of step410. The processor112turns on the first relay134aas disclosed in reference to step406, and turns on the second relay134bby applying a second trigger signal of 3.3 volts to 5 volts to the second relay134b. Applying the trigger signals causes the relays134aand134bto close and provide power from the processor power source130to the vibration actuators108aand108b. Providing power to the vibration actuators108band108bcauses the vibration actuators108band108bto vibrate at 30 cycles per second to 300 cycles per second, with a combined intensity than the first plurality of vibration actuators108aalone. The higher intensity vibration may advantageously relieve the tremors in the patient. The processor112maintains the trigger signals to the relays134aand134bfor a second prescribed treatment time, which may be equal to the first prescribed treatment time.

After execution of step410, the method400continues with step412, which includes the processor112transmitting an event record to the recording device136ofFIG.1. The event record includes a date and time that the acceleration exceeded the threshold acceleration value for the threshold time period. The event record may optionally identify the patient. The event record may optionally include additional information, such as magnitude and duration of the acceleration that exceeded the threshold acceleration value. The event record may optionally include information regarding which pluralities of the vibration actuators108band108bwere activated, and the time duration of activation of each plurality. After execution of step412, the method400returns to step402.

Handwriting can be used to assess effectiveness of treatments for tremors.FIG.5throughFIG.7are handwriting samples of different Parkinson's patients, before and after treatment with a Smart Strap. In each case, the Parkinson's patient attempts to write “The quick brown fox jumps over the lazy dog.” While experiencing tremors, and after treatment with a Smart Strap. For each sentence written, the time to write the sentence was recorded. Referring toFIG.5, the handwriting sample labeled “Before:” was made while a first Parkinson's patient was experiencing tremors. The first Parkinson's patient was not able to complete the sentence because of the tremors. After a vibration treatment from the Smart Strap, the first Parkinson's patient completed the sentence, labeled “After:” on a second try, in 51 seconds.

Referring toFIG.6, a second Parkinson's patient was able to complete writing the sentence during tremors, in 25 seconds. After a vibration treatment from the Smart Strap, the second Parkinson's patient was able to complete writing the sentence twice, with reduced times of 22 seconds and 19 seconds.

Referring toFIG.7, a third Parkinson's patient was able to complete writing the sentence during tremors, in 34 seconds. After a vibration treatment from the Smart Strap, the third Parkinson's patient was able to complete writing the sentence twice, with reduced times of 30 seconds and 31 seconds, with improved penmanship.

FIG.8is a chart of average times to write a word during the writing trials described in reference toFIG.5throughFIG.7. Eleven participants completed the writing trials, under three modes: no vibration, low vibration, and high vibration. In the high vibration mode, all the vibration actuators108aand108bofFIG.1were activated. In the low vibration mode, the first plurality of the vibration actuators108awere activated. In the no vibration mode, none of the vibration actuators108aand108bwere activated. For all eleven participants, the average time to write a word significantly improved in the high vibration mode compared to the no vibration mode. In the high vibration mode, two of the participants had average times between 4 seconds and 6 seconds, five of the participants had average times between 2 seconds and 4 seconds, and four of the participants had average times between 1 second and 2 seconds. In the high vibration mode, ten of the participants had modest improvements in the average times, and one participant had a slight increase in the average time. The high vibration mode in the treatment with a Smart Strap is observed to provide an improvement in the average times to write a word during the writing trials.

FIG.9is a chart of the impact of the treatments with a Smart Strap on the quality of penmanship in the writing trials described in reference toFIG.5throughFIG.7. For the eleven participants, penmanship was designated as no change, better, significantly better, worse, or significantly worse. The no vibration mode was used as a control mode, so all participants were designated to have no change in the no vibration mode. In the high vibration mode, four of the participants exhibited better penmanship, six of the participants exhibited significantly better penmanship, and one of the participants exhibited no change in penmanship quality. None of the participants exhibited degraded penmanship in the high vibration mode. In the low vibration mode, two of the participants exhibited worse penmanship, two of the participants exhibited no change in penmanship quality, and seven of the participants exhibited better penmanship. None of the participants exhibited significantly worse penmanship in either the low vibration mode or the high vibration mode. The high vibration mode in the treatment with a Smart Strap is observed to provide an improvement in penmanship for most participants during the writing trials.

Manual manipulation of objects can also be used to assess effectiveness of treatments for tremors.FIG.10is a chart of times to transfer beads from a first container to a second container using a spoon, for three participants. The bead transfer trials were completed under three modes: no vibration, low vibration, and high vibration, as disclosed in reference toFIG.8. For all three participants, the time to transfer beads improved by an average of 7 percent in the low vibration mode compared to the no vibration mode, and improved by 19 percent in the high vibration mode compared to the low vibration mode. The high vibration mode in the treatment with a Smart Strap is observed to provide an improvement in the times to transfer beads.

FIG.11is a chart showing the effectiveness of vibration level on reducing tremor intensity. A group of patients with tremors were monitored with the Smart Strap100under three modes: no vibration, low vibration, and high vibration, as disclosed in reference toFIG.8. The chart inFIG.11shows the total ranges of tremor intensities for each of the three modes, ranges of +/−1 standard deviation, and median values. High values of the total ranges of tremor intensities decreases as the vibration level increases from no vibration to low vibration, and decreases more from low vibration to high vibration. The +1 standard deviation values and the −1 standard deviation values similarly decrease as the vibration level increases. The median values decrease by 28 percent as the vibration level increases from no vibration to low vibration, and decrease by 15 percent as the vibration level increases from low vibration to high vibration. Reduction in tremor intensity is well correlated with increase in vibration level.

FIG.12is chart of acceleration of the motion sensor110ofFIG.1for cases of no tremors versus cases of tremors, in two Parkinson's patients. Acceleration values were taken while each Parkinson's patient was wearing the Smart Strap on their wrist. For a first Parkinson's patient,31acceleration values were acquired. Of these 31 acceleration values,17were acquired while the first Parkinson's patient was not experiencing tremors, and14were acquired while the first Parkinson's patient was experiencing tremors. For a second Parkinson's patient,29acceleration values were acquired. Of these 29 acceleration values,15were acquired while the second Parkinson's patient was not experiencing tremors, and14were acquired while the second Parkinson's patient was experiencing tremors.

Thus,32acceleration values were acquired while the two Parkinson's patients were not experiencing tremors. One of these 32 acceleration values was between 3.2 g and 3.4 g, and the remaining 31 acceleration values were between 0.2 g and 1.6 g. Also,28acceleration values were acquired while the two Parkinson's patients were experiencing tremors. All of these 32 acceleration values were between 3.2 g and 3.6 g.

As seen inFIG.12, a threshold range between 1.7 g and 2.2 g separates the acceleration values without tremors from the acceleration values with tremors, with the exception of the one acceleration value without tremors for the first Parkinson's patient. Thus, a threshold acceleration value within the threshold range is deemed effective in discriminating normal wrist motions from tremors.