Pendulum test: Quantified assessment of the type and level of spasticity in persons with central nervous system lesions

The development of a comprehensive computational model of the pendulum test which is appropriate for the analysis of the pathologic behavior of the leg in humans with the central nervous system (CNS) lesion is presented in this review. The model relates to the pendulum movement of the lower leg (shank and the foot) in the lateral plane due to the gravity and involuntary contractions of the muscles. The viscous damping and elastic stiffness reflect the soft tissues and friction in the knee joint. To quantify the pathologic activity of paralyzed muscles a reflex torque was added to the gravity generated knee joint torque. The knee joint encoder, accelerometers and gyroscopes positioned along the shank and thigh, and EMG amplifiers were used to acquire data for the illustration of the validity of the model. We show that the linear model of the movement of the lower leg is not a good representation of the motor impairment. We show that the model expanded with the reflex torque affecting the movement is well suited for the pendulum analysis. The timing of the reflex torques can be determined from the EMG recordings. © Serbian Journal of Electrical Engineering. 2018

A new method and instrumentation for analyzing spasticity

The assessment of spasticity is an important indicator of the course of the recovery in humans with central nervous system lesion. This recovery may be augmented by optimal ergonomic design of wheelchairs, beds, transferring devices and other devices used in activities of daily life. To quantify the influence of different aids and methods in reduction or increase of spasticity, an objective measure is required. The pendulum test was introduced to induce the stretch of the muscle, thereby, trigger spastic response, and the amplitudes of first sinusoidal movements are used as the measure of spasticity. We present a new model of the lower leg during the pendulum test which includes the nonlinear characteristics of the muscles, and a model of the shank and foot that are customized to the patient. The spastic torque component is calculated based on acquired values of angular acceleration, angular velocity, and angle. We developed a new analysis methodology and tool to describe the level and course of reflexive behavior. We describe the instrumentation for data acquisition. The kinematics is captured by two accelerometers, one gyroscope, and a Hall-effect joint angle encoder. Muscle activities of prime knee flexors and extensors are synchronously recorded. The simulation uses user's particular inertial parameters and data from repeated pendulum movements of the lower leg and outputs the reflexive torque. We developed the user-friendly software in MatLab for the analysis of data recorded with the new instrument. We present the application of the method in representative healthy subject and two spastic SCI patients. The main finding is that this method allows distinction between the flexion and extensions types of spasticity and the level of reflexive behavior

Robotics / Tadej Bajd ... [et al.].

Includes bibliographical references (p. 149) and index.Book fair 2013.viii, 152 p.

Muscle Contracture Emulating System for Studying Artificially Induced Pathological Gait in Intact Individuals

When studying pathological gait it is important to correctly identify primary gait anomalies originating from damage to the central nervous and musculoskeletal system and separate them from compensatory changes of gait pattern, which is often challenging due to the lack of knowledge related to biomechanics of pathological gait. A mechanical system consisting of specially designed trousers, special shoe arrangement, and elastic ropes attached to selected locations on the trousers and shoes is proposed to allow emulation of muscle contractures of soleus (SOL) and gastrocnemius (GAS) muscles and both SOL-GAS. The main objective of this study was to evaluate and compare gait variability as recorded in normal gait and when being constrained with the proposed system. Six neurologically and orthopedically intact volunteers walked along a 7-m walkway while gait kinematics and kinetics were recorded using VICON motion analysis system and two AMTI forceplates. Statistical analysis of coeffi cient of variation of kinematics and kinetics as recorded in normal walking and during the most constrained SOL-GAS condition showed comparable gait variability

Rehabilitation Robot Cell for Multimodal Standing-Up Motion Augmentation ∗

Abstract — The paper presents a robot cell for multimodal standing-up motion augmentation. The robot cell is aimed at augmenting the standing-up capabilities of impaired or paraplegic subjects. The setup incorporates the rehabilitation robot device, functional electrical stimulation system, measurement instrumentation and cognitive feedback system. For controlling the standing-up process a novel approach was developed integrating the voluntary activity of a person in the control scheme of the rehabilitation robot. The simulation results demonstrate the possibility of “patient-driven ” robotassisted standing-up training. Moreover, to extend the system capabilities, the audio cognitive feedback is aimed to guide the subject throughout rising. For the feedback generation a granular synthesis method is utilized displaying highdimensional, dynamic data. The principle of operation and example sonification in standing-up are presented. In this manner, by integrating the cognitive feedback and “patientdriven” actuation systems, an effective motion augmentation system is proposed in which the motion coordination is under the voluntary control of the user. Index Terms — Rehabilitation robotics, standing-up, voluntary control, audio cognitive feedback, granular synthesis

Pendulum test: Quantified assessment of the type and level of spasticity in persons with central nervous system lesions

The development of a comprehensive computational model of the pendulum test which is appropriate for the analysis of the pathologic behavior of the leg in humans with the central nervous system (CNS) lesion is presented in this review. The model relates to the pendulum movement of the lower leg (shank and the foot) in the lateral plane due to the gravity and involuntary contractions of the muscles. The viscous damping and elastic stiffness reflect the soft tissues and friction in the knee joint. To quantify the pathologic activity of paralyzed muscles a reflex torque was added to the gravity generated knee joint torque. The knee joint encoder, accelerometers and gyroscopes positioned along the shank and thigh, and EMG amplifiers were used to acquire data for the illustration of the validity of the model. We show that the linear model of the movement of the lower leg is not a good representation of the motor impairment. We show that the model expanded with the reflex torque affecting the movement is well suited for the pendulum analysis. The timing of the reflex torques can be determined from the EMG recordings. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR35003