JP2002331007A - Motion assisting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and simply handleable motion assisting apparatus due to FES suitable for a foot-drop patient. SOLUTION: Electrodes 11A and 11B are applied to the skin and the voltage applied across the electrodes 11A and 11B is amplified by an amplifier 12. An analogue signal is converted to a digital signal by an A/D converter and a signal showing the magnitude of voluntary myogenic electricity is sent to an electrical stimulation part 15 by a CPU 14 and the electric signal corresponding to the magnitude of voluntary myogenic electricity is generated in the electrical stimulation part 15 to electrically stimulate a deep fibular nerve through a relay 16, the electrodes 11A and 11B and the skin.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exercise assisting device suitable for, for example, a patient with a foot drop.

2. Description of the Related Art One of the sequelae of hemiplegia due to cerebrovascular disorders is called a drop foot. In patients with drop foot, dorsiflexion of the ankle joint becomes difficult due to relaxation of the dorsiflexor muscle group of the ankle joint and enhancement of the plantar flexor muscle group. For this reason, while walking, the ankle joint dorsiflexes due to the contraction of the dorsiflexor muscles and the leg swings out smoothly in a healthy person, while the ankle joint does not dorsiflex and the toe touches the ground in a drop foot patient . This “drag walking” makes it difficult for the patient to walk.
As an exercise assistive device for such a patient, a shoehorn-type short leg device is known. This ankle brace is made of plastic that covers the entire foot from the sole to the calf and fixes the ankle joint at a right angle. FIG. 3 is a diagram for explaining the principle of a conventionally known functional electrical stimulation. Functional Electrical Stimulation (F)
ES) is known. The FES includes a gait phase detection unit 51 that detects a gait phase by attaching a switch for detecting the gait phase to the sole of the unaffected side, and a central nervous system of a patient with a stroke or spinal cord injury based on the detected gait phase. A control signal generator 52 for generating a control signal that substitutes for a signal descending from the system, and an FES system 53 for providing electrical stimulation to the nerves of the paralyzed muscle based on the control signal, reconstruct the function of the paralyzed limb. It is a cure. Exercise assistive braces using this FES have also been developed, and have the advantage of not only simplifying the appearance when worn compared to short leg orthoses, but also helping patients to recover their functions.

However, in the case of a shoehorn-type short leg limb, the burden on the patient who uses the limb is large, such as the size of the shoes used when worn. In functional electrical stimulation, a switch for detecting the gait phase may be used by attaching it to the sole of the unaffected side. It is difficult at present.
The present invention has been made in view of the above problems, and is small in size and easy to handle.
An object of the present invention is to provide an exercise assist device by FES.

An exercise assisting device according to the present invention generates a first electrode for detecting myoelectricity and a control signal corresponding to the magnitude of the myoelectricity detected by the first electrode. Control means, electrical stimulation means controlled by the control means to generate electrical stimulation, and second electrodes for applying the electrical stimulation generated by the electrical stimulation means. In addition, since the first electrode and the second electrode are shared, the mounting of the device can be made compact.
Further, provided between the electrical stimulation means and the electrode,
By further providing a switch that is turned off when detecting myoelectricity, it is possible to prevent stimulus artifacts from being mixed. Further, the control means can generate a control signal when the myoelectric potential exceeds a predetermined threshold value, thereby detecting an appropriate timing for performing a stimulus in a walking phase.
Further, the electric stimulation means generates an electric stimulation pulse of a pulse width modulation system, which is suitable for applying digital technology.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG.
1 is a block diagram illustrating a configuration of an exercise assisting device according to an embodiment of the present invention. Electrodes 11A, 11B on skin
And the voltage between the electrodes 11A and 11B is
2, the analog signal is converted into a digital signal by the A / D converter 13, and a signal representing the magnitude of voluntary myoelectricity is sent to the electrical stimulating unit 15 by the CPU (central processing unit, ie, microcomputer) 14, The electrical stimulation unit 15 generates an electrical signal corresponding to the magnitude of the voluntary myoelectric potential, and
6, and electrical stimulation of the deep peroneal nerve through the electrodes 11A and 11B and further through the skin. The electrodes 11A and 11B are conductive jelly-like and have a size of a business card. Detects voluntary myoelectricity of the tibialis anterior muscle and electrically stimulates the deep peroneal nerve, the innervating nerve of the dorsiflexors of the ankle joint of the paralyzed limb (tibialis anterior, extensor extensor longus, extensor longus longus, etc.) Apply to a suitable location. The amplifier 12 amplifies a weak voluntary electromyogram to a voltage suitable for signal processing. Here, a variable amplification of 5000 to 50000 times and a pass band of 300 to 500 Hz were used. The A / D converter 13 converts an analog voltage into a digital signal for processing by the CPU 14. Here, the amplitude was captured at a sampling frequency of 10 kHz. The CPU 14 sets a threshold value for the amplitude of the voluntary myoelectricity, and controls the electrical stimulation unit 15 so as to apply a stimulus only when the amplitude exceeds the threshold value. That is, CPU1
No. 4 detects the timing of stimulating in the walking phase. This is because the dorsiflexors contract strongly during the heel contact (heel contact) during the walking swing phase and the early standing phase. In addition, when the electromyogram is detected, the electric stimulating unit 15 and the electrode 11 are used.
The relay 16 is controlled so that A and 11B are insulated. The above control is performed here by a microcomputer (PIC16
C711: Microchip). The electrical stimulation unit 15
Under the control of the PU 14, a bipolar stimulation pulse having a frequency of 15 Hz and a voltage of 100 V is output by a pulse width modulation method in a range of 100 to 500 μs according to the amplitude of the voluntary myoelectricity of the tibialis anterior muscle. The relay 16 is a switch controlled by the CPU 14, and detects the electric stimulating unit 15 and the electrodes 11A and 11A when the myoelectricity is detected.
Insulate B to prevent the introduction of stimulating artifacts. Here, a Photo-MOS relay was used. FIG. 2 is an external view of a prototype of the exercise assisting device according to the present embodiment. The portion of the circuit 20 including the CPU 14 is 7 × 7 cm, and is fixed to the back of the knee of the knee joint supporter 40. The power supply is a 9V battery 30
Two (006P) were used and fixed to the inside of the supporter 40. In addition, the electrodes 11A and 11B were previously attached to positions on the tibialis anterior muscle-deep peroneal nerve of the affected foot on the back side of the supporter 40. When an evaluation experiment of this prototype device was performed, no stimulation was output when the amplitude of the voluntary myoelectricity of the tibialis anterior muscle was below the threshold, and when the amplitude exceeded the threshold, a stimulation with a pulse width corresponding to the amplitude of the myoelectricity was output. It was confirmed that it would be. In addition,
The present invention is not limited to the above embodiment. Although the pulse width modulation is used in the above embodiment, it is sufficient that the effective voltage of the signal can be changed, and instead, pulse frequency modulation or pulse amplitude modulation may be used. The drive may be voltage drive or current drive. In the above-described embodiment, the present invention is applied to a drop foot. However, since a signal is applied by detecting myoelectricity, the present invention may be applied to other muscles such as an arm. Further, the electrode may be a needle electrode.

As described above, according to the present invention, the contraction of the dorsiflexors and the dorsiflexion of the ankle joint, which are similar to walking of a healthy person, can be obtained. In addition, a therapeutic effect such as improvement of voluntary contraction of the dorsiflexor muscle group can be expected through use of the exercise assisting device of the present invention. By using myoelectricity as a trigger for stimulus output, the sole switch used in the conventional FES device becomes unnecessary. Further, by using the same stimulating electrode and myoelectric detection electrode, the device can be compactly mounted and electrical stimulation can be accurately applied to the muscles that have detected myoelectricity.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an exercise assisting device according to an embodiment of the present invention.

FIG. 2 is an external view of a prototype of the exercise assisting device of the present embodiment.

FIG. 3 is a diagram illustrating the principle of a conventionally known functional electrical stimulation.

[Explanation of symbols]

 11A, 11B Electrode 12 Amplifier 13 Converter 14 CPU 15 Electrical stimulation unit 16 Relay 20 circuit 30 Dry battery 40 Supporter 51 Walking phase detection unit 52 Control signal generation unit 53 FES system

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[Procedure amendment]

[Submission date] January 22, 2002 (2002.1.2
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Detailed description of the invention

[Correction method] Change

[Correction contents]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exercise assisting device suitable for, for example, a patient with a foot drop.

[0002]

2. Description of the Related Art One of the sequelae of hemiplegia due to cerebrovascular disorders is called a drop foot. In patients with drop foot, dorsiflexion of the ankle joint becomes difficult due to relaxation of the dorsiflexor muscle group of the ankle joint and enhancement of the plantar flexor muscle group. For this reason, while walking, the ankle joint dorsiflexes due to the contraction of the dorsiflexor muscles and the leg swings out smoothly in a healthy person, while the ankle joint does not dorsiflex and the toe touches the ground in a drop foot patient . This “drag walking” makes it difficult for the patient to walk.

[0003] As an exercise assistive device for such patients, a shoehorn-type short leg device is known. This ankle brace is made of plastic that covers the entire foot from the sole to the calf and fixes the ankle joint at a right angle.

FIG . 3 is a view for explaining the principle of a conventionally known functional electrical stimulation. Functional Electrical Stimul is a method for reconstructing the function of paralyzed limbs.
ation: FES) is known. The FES includes a gait phase detection unit 51 that detects a gait phase by attaching a switch for detecting the gait phase to the sole of the unaffected side, and a central nervous system of a patient with a stroke or spinal cord injury based on the detected gait phase. A control signal generator 52 for generating a control signal that substitutes for a signal descending from the system, and an FES system 53 for providing electrical stimulation to the nerves of the paralyzed muscle based on the control signal, reconstruct the function of the paralyzed limb. It is a cure. Exercise assistive braces using this FES have also been developed, and have the advantage of not only simplifying the appearance when worn compared to short leg orthoses, but also helping patients to recover their functions.

[0005]

However, in the case of a shoehorn-type short leg limb, the burden on the patient who uses the limb is large, such as the size of the shoes used when worn.

[0006] In functional electrical stimulation, a switch for detecting a walking phase may be used by attaching it to the sole of the unaffected side. It is currently difficult to use.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a small and easy-to-handle FES exercise assisting device.

[0008]

An exercise assisting device according to the present invention generates a first electrode for detecting myoelectricity and a control signal corresponding to the magnitude of the myoelectricity detected by the first electrode. Control means, electrical stimulation means controlled by the control means to generate electrical stimulation, and second electrodes for applying the electrical stimulation generated by the electrical stimulation means.

Further , since the first electrode and the second electrode are shared, the mounting of the device can be made compact.

[0010] Further, a switch provided between the electric stimulating means and the electrode and turned off when detecting myoelectricity is further provided, thereby preventing the stimulus artifact from being mixed.

[0011] Further , the control means generates the control signal when the myoelectricity exceeds a predetermined threshold value, so that it is possible to detect an appropriate timing for stimulating in the walking phase.

Further , the electric stimulation means generates an electric stimulation pulse of a pulse width modulation system, which is suitable for applying digital technology.

[0013]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG . 1 is a block diagram for explaining the structure of an exercise assisting device according to one embodiment of the present invention. The electrodes 11A and 11B are applied to the skin, the voltage between the electrodes 11A and 11B is amplified by the amplifier 12, the analog signal is converted to the digital signal by the A / D converter 13, and the CPU (central processing unit, ie, microcomputer) ) At 14, a signal representing the magnitude of the voluntary myoelectricity is sent to the electric stimulating unit 15, and the electric stimulating unit 15 generates an electric signal according to the magnitude of the voluntary myoelectricity, and the relay 16, the electrodes 11 </ b> A, 11 </ b> B, and Electrical stimulation of the deep peroneal nerve through the skin.

The electrodes 11A and 11B are in the form of a conductive jelly and have the size of a business card. Detects voluntary myoelectricity of the tibialis anterior muscle and electrically stimulates the deep peroneal nerve, the innervating nerve of the dorsiflexors of the ankle joint of the paralyzed limb (tibialis anterior, extensor extensor longus, extensor longus longus, etc.) Apply to a suitable location.

The amplifier 12 amplifies a weak voluntary electromyogram to a voltage suitable for signal processing. Here, a variable amplification of 5000 to 50000 times and a pass band of 300 to 500 Hz were used.

The A / D converter 13 converts the analog voltage into a CP
It is converted to a digital signal for processing in U14. Here, the amplitude was captured at a sampling frequency of 10 kHz.

The CPU 14 sets a threshold value for the amplitude of the voluntary myoelectricity, and controls the electrical stimulation unit 15 so as to apply a stimulus only when the amplitude exceeds the threshold value. That is, CPU
Numeral 14 detects the timing of stimulating in the walking phase. This is because the dorsiflexors contract strongly during the heel contact (heel contact) during the walking swing phase and the early standing phase. In addition, the electric stimulating unit 15 and the electrode
The relay 16 is controlled so as to insulate the relays 1A and 11B.
The above control is performed here by a microcomputer (PIC
16C711: Microchip).

The electrical stimulating unit 15 is controlled by the CPU 14 to control the frequency of 15 Hz and the voltage of 100 by pulse width modulation in the range of 100 to 500 μs according to the amplitude of the voluntary electromyography of the tibialis anterior muscle.
Output a V bipolar stimulus pulse.

The relay 16 is a switch controlled by the CPU 14. The relay 16 and the electrode 11
A, 11B are insulated to prevent the introduction of stimulating artifacts. Here, a Photo-MOS relay was used.

FIG . 2 is an external view of a prototype of the exercise assisting device of the present embodiment. The portion of the circuit 20 including the CPU 14 is 7 × 7 cm, and is fixed to the back of the knee of the knee joint supporter 40. The power supply used two 9 V dry batteries 30 (006P) and was fixed to the inside of the supporter 40. The electrode 11
A and 11B were previously attached to positions on the tibialis anterior muscle-deep peroneal nerve of the affected foot that hit the back of the supporter 40.

When an evaluation experiment was conducted on the prototype device, no stimulation was output when the amplitude of the voluntary myoelectricity of the tibialis anterior muscle was below the threshold, and when the amplitude exceeded the threshold, the pulse width corresponding to the amplitude of the myoelectric potential was increased. It was confirmed that the stimulus was output.

The present invention is not limited to the above embodiment.

In the above embodiment, the pulse width modulation is used, but it is sufficient that the effective voltage of the signal can be changed, and instead, pulse frequency modulation or pulse amplitude modulation may be used. The drive may be voltage drive or current drive.

In the above-described embodiment, the present invention is applied to a drop foot. However, since a signal is applied by detecting myoelectricity, it is used for other muscles such as an arm. Is also good.

The electrodes may be needle electrodes.

[0027]

As described above, according to the present invention, the contraction of the dorsiflexors and the dorsiflexion of the ankle joint, which are similar to walking of a healthy person, can be obtained.

In addition, a therapeutic effect such as improvement in voluntary contraction of the dorsiflexors can be expected through use of the exercise assisting device of the present invention.

By using myoelectricity as a trigger for stimulus output, the sole switch used in the conventional FES device becomes unnecessary.

Furthermore, by identification with the stimulation electrode and the myoelectric detection electrode can provide accurate electrical stimulation to muscles mounting the device detects myoelectric with made compact.

Claims (5)

[Claims] A first electrode for detecting a myoelectric potential; a control means for generating a control signal corresponding to a magnitude of the myoelectric potential detected by the first electrode; and an electric power controlled by the control means. An exercise assisting device comprising: an electric stimulus unit that generates a stimulus; and a second electrode that applies an electric stimulus generated by the electric stimulus unit. 2. The exercise assisting device according to claim 1, wherein the first electrode and the second electrode are shared. 3. The exercise assisting device according to claim 2, further comprising a switch provided between the electric stimulation unit and the electrode and turned off when a myoelectricity is detected. 4. The exercise assisting device according to claim 1, wherein the control unit generates the control signal when the electromyogram exceeds a predetermined threshold. 5. The exercise assisting device according to claim 1, wherein said electrical stimulation means generates a pulse width modulation type electrical stimulation pulse.