A novel sensor-based assessment of lower limb spasticity in children with cerebral palsy

Abstract

BackgroundTo provide effective interventions for spasticity, accurate and reliable spasticity assessment is essential. For the assessment, the Modified Tardieu Scale (MTS) has been widely used owing to its simplicity and convenience. However, it has poor or moderate accuracy and reliability.MethodsWe proposed a novel inertial measurement unit (IMU)-based MTS assessment system to improve the accuracy and reliability of the MTS itself. The proposed system consists of a joint angle calculation algorithm, a function to detect abnormal muscle reaction (a catch and clonus), and a visual biofeedback mechanism. Through spastic knee and ankle joint assessment, the proposed IMU-based MTS assessment system was compared with the conventional MTS assessment system in 28 children with cerebral palsy by two raters.ResultsThe results showed that the proposed system has good accuracy (root mean square error < 3.2°) and test-retest and inter-rater reliabilities (ICC > 0.8), while the conventional MTS system has poor or moderate reliability. Moreover, we found that the deteriorated reliability of the conventional MTS system comes from its goniometric measurement as well as from irregular passive stretch velocity.ConclusionsThe proposed system, which is clinically relevant, can significantly improve the accuracy and reliability of the MTS in lower limbs for children with cerebral palsy.

Inertial Sensor-Based Lower Limb Joint Kinematics: A Methodological Systematic Review

“…The study characteristics summarized in Table 1 cover participant information, protocol of the conducted study and sensor set-up. Only four out of the thirty-one included studies involved more than ten participants [16][17][18][19]. Furthermore, a predominantly healthy population was recruited, except for identified populations with ankle osteoarthritis [17], transfemoral amputation [20], incomplete spinal cord injury [21], children with cerebral palsy (CP) [19] and stroke patients [22].…”

“…Among the thirty-one studies included in this review, gait was the most commonly evaluated activity, which was assessed either on a treadmill [16,17,23,24] or a walkway [20][21][22][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. Functional movements (i.e., sit-to-stand, squat) are the next most common activities [18,19,32,[39][40][41]. Furthermore, seven studies focused on more dynamic types of locomotion such as common daily activities [24] and sports, including ski racing [42], running [38,43,44], standing long jump [45] and cycling [46].…”

“…To this end, most commonly assessed was the combination of the full sagittal lower limb (hip, knee, ankle) [24,30,31,34,38,41,45]. Second most common combination was the assessment of the sagittal knee and ankle joint movement [16,19,20,27].…”

“…Four studies opted for a more distal placement on the segments [18,22,35,37]. Only three out of thirty-one studies were able to provide a reproducible description of sensor placement based on anatomical landmarks [19,38,42]. Most of the studies only used three-axes gyroscopes and three-axes accelerometers [17][18][19][20]22,25,26,30,31,33,34,[37][38][39]42,44].…”

“…Only three out of thirty-one studies were able to provide a reproducible description of sensor placement based on anatomical landmarks [19,38,42]. Most of the studies only used three-axes gyroscopes and three-axes accelerometers [17][18][19][20]22,25,26,30,31,33,34,[37][38][39]42,44]. Six studies additionally incorporated a magnetometer [24,29,32,43,45,46].…”