JP2015085034A - Assist device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce unnecessary electrical stimulation to a paralyzed lower limb.SOLUTION: An assist device for assisting a patient with a paralyzed lower limb in walking includes: a first sensor for detecting first information indicating a movement in the forward direction of a lower end part of the paralyzed lower limb; a second sensor for detecting second information indicating a movement in the vertical direction of the lower end part; and a control part for controlling electrical stimulation given to a muscle of the paralyzed lower limb based on the first information and the second information.

Description

  The present invention relates to an auxiliary device for assisting walking of a patient having a paralyzed lower limb.

  Stroke hemiplegic patients have flaccid or spastic paralysis in the lower limbs after illness. Loose paralysis can result in a so-called drooping foot where the toes of the lower limbs buckle more than normal. In the walking motion of a patient with a foot drop, the toes buckle in the first part of the free leg kicking out the lower limb of the paralyzed side, and the latter part of the free leg is reached as it is. As a result, the toes may land before the heel and fall over.

  Patent Document 1 describes a walking assist device that applies an electrical stimulation signal to the paralyzed muscles of an affected foot via an electrode. The walking assist device includes an acceleration sensor that detects the landing of an affected foot, an automatic delay circuit that outputs a pulse signal having a duration corresponding to a part of the immediately preceding walking cycle period from the time of landing detection by the acceleration sensor, An acupuncture time setting circuit that outputs a stimulation time setting signal in response to the pulse signal from the automatic delay circuit, and an electrical stimulation signal in a period corresponding to the duration of the stimulation time setting signal from the stimulation time setting circuit And a pulse generation circuit for outputting.

Japanese Patent Application Laid-Open No. 60-119949

  In the walking assist device described in Patent Document 1, since the electrical stimulation signal is output based only on the signal from the acceleration sensor that detects the landing of the affected foot, for example, although the patient does not intend to walk. First, even when the foot is stepped on or when the affected leg is moved while sitting on a chair, an electrical stimulation signal can be output. Such electrical stimulation signals can cause discomfort and pain to the patient.

  An object of the present invention is to reduce unnecessary electrical stimulation to a paralyzed lower limb and perform electrical stimulation in accordance with walking.

  One aspect of the present invention relates to an auxiliary device that assists walking of a patient having a paralyzed lower limb, wherein the auxiliary device detects first information indicating a forward movement of a lower end portion of the paralyzed lower limb. The first sensor, a second sensor for detecting second information indicating the vertical movement of the lower end, and the paralyzed lower limb muscle based on the first information and the second information. And a control unit for controlling the electrical stimulation applied.

  According to the present invention, unnecessary electrical stimulation to a paralyzed lower limb can be reduced, and electrical stimulation in accordance with walking can be performed.

The figure which shows typically the state with which the auxiliary | assistance apparatus of one Embodiment of this invention was mounted | worn with the paralyzed leg. The figure which shows the structure of the auxiliary | assistance apparatus of one Embodiment of this invention. The figure which illustrates a patient's walk operation and operation | movement of an auxiliary device.

  Hereinafter, the present invention will be described through exemplary embodiments thereof with reference to the accompanying drawings.

  FIG. 1 schematically shows a state where an auxiliary device 100 according to one embodiment of the present invention is attached to a paralyzed lower limb. FIG. 2 shows the configuration of the auxiliary device 100. The assisting device 100 is configured to assist the walking of a patient having a paralyzed lower limb 10. In this specification and the accompanying drawings, the direction in which the patient proceeds by walking, that is, the front direction is defined as the X direction, the vertical direction is defined as the Z direction, and the direction perpendicular thereto is defined as the Y direction.

  The auxiliary device 100 includes a sensor unit 110, an electrode unit 120, and a control unit 150. The sensor unit 110 includes a first sensor 112 for detecting first information indicating movement in the forward direction (X direction) of the lower end portion (for example, the lower portion of the heel) 15 of the paralyzed lower limb 10, and the lower end portion 15 includes a second sensor 114 for detecting second information indicating movement in the vertical direction (Z direction). The sensor unit 112 may further include a third sensor 116 that detects an ankle joint angle of the paralyzed lower limb 10.

  The first sensor 112 and the second sensor 114 can be disposed in the vicinity of the ridge 12 in the lower end portion 15, for example, below the ridge 12. Alternatively, the first sensor 112 and the second sensor 114 may be disposed on the side of the lower end portion 15. The third sensor 116 may be disposed in the vicinity of the toe 14, for example, below the toe 14. Alternatively, the third sensor 116 may be disposed above or to the side of the toe 14. All or a part of the first sensor 112, the second sensor 114, and the third sensor 116 may be incorporated in the shoe 160, or may be attached to the paralyzed lower limb 10.

  The electrode unit 120 includes electrodes 123 and 124. The control unit 150 applies electric stimulation to the muscles (anterior tibialis muscle) and nerves (radial nerves) of the paralyzed lower limb 10 by applying a voltage between the electrodes 123 and 124, thereby moving the toe 14 upward. Raise it. Based on the outputs of the first sensor 112 and the second sensor 114, the control unit 150 controls the electrical stimulation applied to the muscles of the paralyzed lower limb 10 through the electrodes 123 and 124.

  The sensor unit 110 (the first sensor 112, the second sensor 114, and the third sensor 116) and the control unit 150 are connected via a transmission path (for example, a cable) 128. The electrode unit 120 and the control unit 150 are connected via a cable 126. When the electrode part 120 has a power supply (battery), the electrode part 120 and the control part 150 may be connected by radio.

  FIG. 3 exemplarily shows the walking motion of the patient and the motion of the auxiliary device 100. In FIG. 3, “frontward movement amount” is a movement amount of the lower limb 10 in the front direction (X direction) as an example of the first information detected using the first sensor 112. In one example, the first sensor 112 is an acceleration sensor, and the control unit 150 can acquire the amount of movement of the lower limb 10 in the forward direction (X direction) by performing second-order integration of the output of the acceleration sensor. In another example, the first sensor 112 may include an acceleration sensor and an integration circuit that obtains the amount of movement of the lower limb 10 in the forward direction (X direction) by second-order integration of the output of the acceleration sensor. In yet another example, the first sensor 112 may move the lower end of the paralyzed lower limb 10 in the forward direction (X direction) relative to the lower end of the non-paralyzed lower limb (not shown). A sensor for detecting the relative movement of the unit 15 (relative movement amount detection sensor) is included. The relative movement amount detection sensor may include a sensor that detects a distance between a lower end portion of a non-paralyzed lower limb (not shown) and a lower end portion 15 of the paralyzed lower limb 10.

  In FIG. 3, “vertical acceleration” is acceleration in the vertical direction (Z direction) that can be detected using the second sensor 114. The second sensor 114 can typically be an acceleration sensor that outputs information indicating acceleration. In FIG. 3, “height” is the height obtained by the control unit 150 integrating the acceleration in the vertical direction (Z direction) that can be detected using the second sensor 114, that is, the lower limb 10 in the extension direction. This is the position of the lower end portion 15 (second sensor 114). The second sensor 114 may be a height sensor that detects the height of the shoe 160 from the floor or the ground. In this case, the acceleration in the vertical direction (Z direction) causes the output of the height sensor to be the second floor. Obtained by differentiating. The height is an example of second information obtained using the second sensor 114, and “vertical acceleration” is another example of the second information obtained using the second sensor 114.

  In FIG. 3, “Electric stimulation intensity” is the intensity of the electrical stimulation given to the muscles of the lower limb 10 paralyzed by the control unit 150 via the electrodes 123 and 124.

  The control unit 150 determines that the lower end 15 of the paralyzed lower limb 10 has started moving forward based on the first information obtained using the first sensor 112, and the lower end based on the second information. In response to determining that 15 has started to rise, the delivery of electrical stimulation to the patient is started. According to such a configuration, when the patient steps on or when the patient moves the lower limb 10 while sitting on a chair, electrical stimulation can be prevented from being applied to the patient.

  In one example, based on the second information obtained by using the second sensor 114, the control unit 150 starts from the lower end 15 of the lower limb 10 descending from the maximum height position until the lower end 15 is landed. The electrical stimulation is controlled so that there is a timing at which the electrical stimulation is maximized during the period P. That is, in one example, the circuit 150 controls the electrical stimulation so that there is a timing at which the electrical stimulation is maximized in the later stage of the swing leg. Here, the timing at which the lower end 15 of the lower limb 10 starts to descend from the maximum height position is grasped as the timing at which the acceleration in the vertical direction (Z direction) that can be detected using the second sensor 114 becomes a negative value. May be.

  When the third sensor 116 is provided, the circuit 150 determines that the lower end 15 of the lower limb 1 has started to descend from the maximum height position based on the second information obtained using the second sensor 114. And, based on the output of the third sensor 116, when it is determined that the paralyzed lower limb 10 is in the plantar flexion state, the electrical stimulation to the patient is strengthened. The third sensor 116 may include, for example, a gyro sensor configured to be attached to the toe of the paralyzed leg 10.

  The controller 150 may be configured to determine the intensity of the electrical stimulation according to a function 157 that takes the first information obtained using the first sensor 112 and the second information obtained using the second sensor 114 as arguments. The control unit 150 may include an adjustment unit 155 that adjusts the function 157. For example, the function 157 can be defined as I = α × A + β × B where A is the first information, B is the second information, and I is the intensity of the electrical stimulation. Here, α and β are constants, and the adjustment unit 155 may have a function of changing α and β according to an instruction from a user such as a patient.

Claims (10)

An assist device for assisting a patient with a paralyzed lower limb,
A first sensor for detecting first information indicating movement in a forward direction of a lower end of the paralyzed lower limb;
A second sensor for detecting second information indicating movement of the lower end portion in the vertical direction;
Based on the first information and the second information, a control unit for controlling electrical stimulation applied to the paralyzed lower limb muscles;
An auxiliary apparatus comprising: The controller determines that the lower end has started to move forward based on the first information, and has determined that the lower end has started to rise based on the second information. In response, the electrical stimulation is initiated,
The auxiliary device according to claim 1. Based on the second information, the control unit has a timing at which the electrical stimulation becomes maximum during a period from when the lower end starts to descend from the maximum height position until the lower end reaches the floor. Controlling the electrical stimulation to be present,
The auxiliary device according to claim 1 or 2, characterized in that. The second sensor includes an acceleration sensor, and the control unit obtains a position of the lower end portion in the vertical direction as the second information by performing second-order integration of the output of the acceleration sensor.
The auxiliary device according to any one of claims 1 to 3, wherein The second sensor includes an acceleration sensor, and the control unit acquires acceleration in the vertical direction of the lower end portion detected by the acceleration sensor as the second information.
The auxiliary device according to any one of claims 1 to 3. A third sensor for detecting an ankle joint angle of the paralyzed lower limb;
Based on the second information, the control unit determines that the lower end has started to descend from a maximum height position, and the paralyzed lower limb is in a plantar flexion state based on the output of the third sensor. When it is determined that the electrical stimulation is strong,
The auxiliary device according to any one of claims 1 to 5, wherein: The third sensor includes a gyro sensor configured to be attached to a toe of the paralyzed leg.
The auxiliary device according to claim 6. The first sensor includes a sensor for detecting a relative movement of the lower end portion of the paralyzed lower limb with respect to a lower end portion of the non-paralyzed lower limb as the first information.
The auxiliary device according to any one of claims 1 to 7, characterized in that: The control unit determines the intensity of the electrical stimulation according to a function having the first information and the second information as arguments.
The auxiliary device according to any one of claims 1 to 8, characterized in that: The control unit includes an adjustment unit that adjusts the function.
The auxiliary device according to claim 9.