Method for identifying and evaluating parallel motor control function in the brain based on electromyogram signals
View Patent ↗The present invention provides a system for evaluating motor control function in the brain. This system is for evaluating the motor control function in the brain of a subject from the electromyogram (EMG) data of joint prime movers and the data on the position, velocity and acceleration of the joint, wherein both of the data have been obtained by measuring a target-tracking movement performed by the subject with a motion measurement unit that tracks a moving target, the system comprising the following means (a) to (c): (a) means for separating the frequencies of the EMG data and the frequencies of the data on the position, velocity and acceleration into a plurality of frequency components; (b) means for determining the ratio of viscosity coefficient to elastic coefficient (B/K ratio) for each of the frequency components by applying the EMG data and the data on the position, velocity and acceleration to a specific movement equation; and (c) means for evaluating the causal relationship between the motor control function in the brain and the target-tacking movement using the B/K ratio as an index.
1. A system for evaluating the motor control function in the brain of a subject from the electromyogram (EMG) data of joint prime movers and the data on the position, velocity and acceleration of the joint, wherein both of said data have been obtained by measuring a target-tracking movement performed by the subject with a motion measurement unit that tracks a moving target, said system comprising a computer, configured using a program or software, to perform the following steps (a) to (c):
(a) separating the frequencies of said EMG data and the frequencies of said data on the position, velocity and acceleration into a plurality of frequency components;
(b) determining the ratio of viscosity coefficient to elastic coefficient (B/K ratio) for each of said frequency components by applying said EMG data and said data on the position, velocity and acceleration to the following movement equation (1):
τ
(
t
)
=
M
θ
¨
(
t
)
+
B
θ
.
(
t
)
+
K
θ
(
t
)
=
∑
i
=
1
k
a
i
T
i
(
t
)
(
1
)
where τ represents joint torque; θ represents joint angle; {umlaut over (θ)} represents the angular velocity of joint; {dot over (θ)} represents the angular acceleration of joint; M represents the moment of inertia; B represents viscosity coefficient; K represents elastic coefficient; T i (t) represents muscle tension; a i represents optimal approximation coefficient between joint torque and the linear sum of muscle tension; and k represents the number of prime movers; and
(c) evaluating the causal relationship between the target-tacking movement and the motor control function in the brain using said B/K ratio as an index.
2. The system according to claim 1 , wherein the EMG data are obtained by normalizing the magnitude of the EMG signals in proportion to the magnitude of joint torque, full-wave rectifying the thus normalized signals and filtering the resultant signals with a low-pass filter.
3. The system according to claim 1 , wherein said frequency components consist of two components of low frequency component and high frequency component.
4. The system according of claim 3 , wherein the boundary between said two frequency components is within the range from 0.3 to 0.8 Hz.
5. The system according to claim 1 , wherein said subject is a patient with neurological disorder.
6. The system according to claim 1 , wherein said joint prime movers are arm muscles.
7. The system according to claim 6 , wherein said arm muscle is at least one selected from extensor carpi radialis (ECR), extensor carpi ulnaris (ECU), flexor carpi ulnaris (FCU) and flexor carpi radialis (FCR).
8. A non-transitory computer-readable record medium storing a program for evaluating the motor control function in the brain of a subject from the electromyogram (EMG) data of joint prime movers and the data on the position, velocity and acceleration of the joint, wherein both of said data have been obtained by measuring a target-tracking movement performed by the subject with a motion measurement unit that tracks a moving target, said program being for the purpose of bringing the following steps (a) to (c) into practice:
(a) separating the frequencies of said EMG data and the frequencies of said data on the position, velocity and acceleration into a plurality of frequency components;
(b) determining the ratio of viscosity coefficient to elastic coefficient (B/K ratio) for each of said frequency components by applying said EMG data and said data on the position, velocity and acceleration to the following movement equation (1):
τ
(
t
)
=
M
θ
¨
(
t
)
+
B
θ
.
(
t
)
+
K
θ
(
t
)
=
∑
i
=
1
k
a
i
T
i
(
t
)
(
1
)
where τ represents joint torque; θ represents joint angle; {umlaut over (θ)} represents the angular velocity of joint; {dot over (θ)} represents the angular acceleration of joint; M represents the moment of inertia; B represents viscosity coefficient; K represents elastic coefficient; T i (t) represents muscle tension; a i represents optimal approximation coefficient between joint torque and the linear sum of muscle tension; and k represents the number of prime movers; and
(c) evaluating the causal relationship between the target-tacking movement and the motor control function in the brain using said B/K ratio as an index.
9. A method for evaluating the motor control function in the brain of a subject from the electromyogram (EMG) data of joint prime movers and the data on the position, velocity and acceleration of the joint, wherein both of said data have been obtained by measuring a target-tracking movement performed by the subject with a motion measurement unit that tracks a moving target, said method comprising using a program or software on a computer or system, configured using the program or software, to perform the following steps (a) to (c):
(a) separating the frequencies of said EMG data and the frequencies of said data on the position, velocity and acceleration into a plurality of frequency components;
(b) determining the ratio of viscosity coefficient to elastic coefficient (B/K ratio) for each of said frequency components by applying said EMG data and said data on the position, velocity and acceleration to the following movement equation (1):
τ
(
t
)
=
M
θ
¨
(
t
)
+
B
θ
.
(
t
)
+
K
θ
(
t
)
=
∑
i
=
1
k
a
i
T
i
(
t
)
(
1
)
where τ represents joint torque; θ represents joint angle; {dot over (θ)} represents the angular velocity of joint; {umlaut over (θ)} represents the angular acceleration of joint; M represents the moment of inertia; B represents viscosity coefficient; K represents elastic coefficient; T i (t) represents muscle tension; a i represents optimal approximation coefficient between joint torque and the linear sum of muscle tension; and k represents the number of prime movers; and
(c) evaluating the causal relationship between the target-tacking movement and the motor control function in the brain using said B/K ratio as an index.
10. A method of processing the electromyogram (EMG) data of joint prime movers and the data on the position, velocity and acceleration of the joint obtained by measuring a target-tracking movement performed by the subject with a motion measurement unit that tracks a moving target, said method comprising using a program or software on a computer or system, configured using the program or software, to perform the following steps (a) and (b):
(a) separating the frequencies of said EMG data and the frequencies of said data on the position, velocity and acceleration into a plurality of frequency components;
(b) determining the ratio of viscosity coefficient to elastic coefficient (B/K ratio) for each of said frequency components by applying said EMG data and said data on the position, velocity and acceleration to the following movement equation (1):
τ
(
t
)
=
M
θ
¨
(
t
)
+
B
θ
.
(
t
)
+
K
θ
(
t
)
=
∑
i
=
1
k
a
i
T
i
(
t
)
(
1
)
where τ represents joint torque; θ represents joint angle; {dot over (θ)} represents the angular velocity of joint; {umlaut over (θ)} represents the angular acceleration of joint; M represents the moment of inertia; B represents viscosity coefficient; K represents elastic coefficient; T i (t) represents muscle tension; a i represents optimal approximation coefficient between joint torque and the linear sum of muscle tension; and k represents the number of prime movers.