Gait Analysis In Children With Spastic Cerebral Palsy Based On Inertial Sensor Motor Capture System

Background:Cerebral palsy(CP)is the most common cause of physical disability in children,with a prevalence of 0.2%-0.35%.Spastic diplegia accounts for about 37% of the total number of CP,whose mainly clinical symptom is the dysfunction of both lower limbs.When walking,the children with spastic diplegia is prone to "scissor legs",pointed feet and crouching gait,which can seriously limits children’s participation in daily social life activities.It is difficult to formulate a good rehabilitation plan if we cannot accurately understand the gait characteristics of children with CP,and the treatment effect is limited.Gait analysis can analyze and summarize the characteristics and causes of abnormal gait in children with CP,which is important for clinical diagnosis and rehabilitation.At present,the optical motion capture system commonly used in clinical practice,which can accurately and quantitatively analyze the gait-related parameters of children with CP and effectively assist clinical professionals in diagnosis and formulate treatment plans.However,there are some problems in optical motion capture system,such as large site requirements,high equipment costs,long testing time,and high requirements for cooperation with children.Therefore,it is mainly used for laboratory research and clinical promotion is limited.Therefore,it is urgently to find a gait assessment tool that can rapidly and accurately analysis the gait of children with CP in daily life.The motion capture system based on inertial sensors has those advantages,such as small size,low energy consumption,and cheapness.It can break through the limitations of existing gait analysis methods and observe the gait characteristics of children in daily environments.It seems promising to open a new dimension for children’s gait assessment.However,the domestic research in this area is mainly focused on adults,and there are few reports on children’s applied research.Therefore,this study used a motion capture system based on inertial sensors to observe and analyze the gait characteristics of CP children and healthy children walking in daily life environment at natural pace,in order to provide a new method and scientific basis for the clinical evaluation of CP.Method:This study is a cross-sectional observational study(ethics number: No.2020-26;trial registration number: Chi CTR2000032679).From June to December 2020,20 children with CP from 6-12 years old who met the inclusion criteria were recruited at the Rehabilitation Department of Guangzhou Women and Children Medical Center.And 20 normal children of the same age were recruited from the society.After the parents signed the informed consent form,the basic data of all children were collected,for example age,gender,height,weight,body mass index(BMI).In addition,the score of the gross motor function measure(GMFM),the grade of gross motor function classification system(GMFCS)of children with CP were collected.And the modified Ashworth scale(MAS)grading of the spastic muscles of both lower extremities also were collected.After collecting the basic data,two researchers used the motion capture system based on inertial sensors to collect and analyze the gait spatiotemporal parameters,(such as walking period,support phase,swing phase,speed,stride length,cadence,kinematic parameters of each joint of the lower limbs(hip,knee,ankle)and three-dimensional movement of the waist(anterior flexion,posterior extension,leftright flexion,left-right rotation))of all children walking 20 meters in the hospital corridor at natural pace.Establish a database with Microsoft Excel,use SPSS 20.0(SPSS Inc.,Chicago,IL,USA)statistical software for data analysis,use independent sample T test or non-parametric rank sum test to compare the two sets of data.The significance level was set at 5%(P<0.05).ResultThere was no statistically significant difference in age,gender,height and BMI between the two groups;Comparing the gait time and space parameters of the two groups,the gait cycle of children with CP became longer,and the proportion of the support phase in the entire cycle increased,and the proportion of the swing phase decreased;the step length became shorter and the cadence accelerated,the difference was statistically significant(P< 0.05);although the speed of children with CP was slow,the difference was not statistically significant(P>0.05);Comparison of the kinematic parameters of the hip,knee,and ankle joints between the two groups.The hip flexion and extension angles of children with CP are limited;the internal rotation angle of the hip increases,and the external rotation angle decreases(P<0.05);the knee flexion angle and the angle of plantar flexion of the ankle joint is limited(P<0.05);other kinematic parameters no obvious change in the children(P>0.05);Comparison of the threedimensional movement angles of the waist of the two groups,the angles of waist extension,left and right lateral flexion and right rotation of children with CP increased significantly(P < 0.05);while there was no significant difference between forward flexion and left rotation angles(P>0.05);There is no correlation between the GMFM-88(D/E)scores of children with CP and their gait time-space parameters.There is no correlation between the changes of the kinematic parameters of the hip,knee,and ankle joints of children with CP and the muscle tension of the spastic muscle groups at each joint.ConclusionThe motion capture system based on inertial sensors can effectively distinguish the gait differences between CP children and healthy children in daily life environment;In addition,it also can summarize the gait characteristics of CP children in daily life environment,such as the gait cycle extends,and the proportion of the support phase in the entire cycle increased,and the proportion of the swing phase decreased;the step length was shortened,and the cadence was accelerated;the angle of flexion,extension,external rotation in hip joint were limited,while the internal rotation angle increases;the knee flexion angle and the ankle plantar flexion angle were limited;the angles of waist extension,lateral flexion,and rotation were increased.