The Best Motion Sensor Localization For Ataxic Gait Assessment

Objective: To distinguish ataxic from normal gait using data from full-body motion capture device. To compare accuracy of various machine learning classifiers. To find the most suitable sensor location for ataxia classification. Background: Gait ataxia is caused by various neurological diseases which affect cerebellum, brain stem and spinal cord and significantly contributes to patients disability. Wireless motion tracking devices along with complex motion analysis has a big potential in early diagnostics and further patient monitoring. In case of walking various parametres such as stride time, step length, rhythm, joint angles and symmetry are used for pathological gait patterns recognition. Perception Neuron is a commercial wearable device containing 32 sensors each composed of gyroscope, accelerometer and magnetometer. Design/Methods: Group of 7 patients with gait ataxia in spinocerebellar type of multiple sclerosis and 7 healthy volunteers were recorded by “Perception Neuron“ while walking. Each recording was divided into several shorter (20s) parts counting 139 segments in total. Power spectral density of accelerometric data was classified by Support Vector Machine, Bayesian Analysis, K-Nearest Neighbours and Neural Networks. Accuraccy for different sensor locations were compared. Results: Best accuracy for different sensors locations was achieved on head, neck and shoulders (up to 99.6%). Accuracy of different classifiers in these locations were comparable with maximal difference 1.8%. The worst results were on feet (65–88%, depending on the classification method) and shanks (76–86%). Conclusions: The evaluation of ataxic walking using motion sensors is a sensitive method, which depends on the location of the sensors. The best accuracy can be achieved by the sensors which are the most distant from the ground. The most likely explanation is the increase of the signal / noise ratio. Noise is comparable for all sensors, while the amplitude of compensatory oscillations increases with distance from the ground. Disclosure: Dr. Dostal has nothing to disclose. Dr. Tupa has nothing to disclose. Dr. Prochazka has nothing to disclose. Dr. Vysata has nothing to disclose. Dr. Pazdera has nothing to disclose. Dr. Valis has nothing to disclose.