Design of Ultrasonic Motion Analysis System for Estimating Segment's Stabilization During Dynamic Condition

Abstract

While the function of central and peripheral nervous system decreases (caused by aging, vestibular deficiency or stroke), maintaining of body stability become hard. Studies indicate that movement coordination of axial segments (head, thorax, and pelvis) in a dynamic state such as walking disrupted in these pathologic conditions. In recent years goniometry and cinematography have been widely used to measure active or passive range of motion (ROM) in asymptomatic adults. The aim of this investigation is to design and implement a new method by evidence based approach for estimating the level of impairment in segment stability and improvement after treatment by measuring quality or quantity of movement among axial segments. Ultrasound based coordinate measuring system (CMS) can continuously measure motion in three dimensions during the course of time in a dynamic condition. The measuring procedure is based on the travel time measurement of ultrasonic pulses that are emitted by miniature transmitters (markers) to three microphones built into the compact device. Our system consist electronic, mechanic and software sections. Electronic board include: 40 KHz pulse oscillator, PRF pulse generator, sensor drivers, high voltage analog switches, 60 dB Amplifier, signal detector and CPU. Transmitter sensors which have been mounted on body send ultrasonic burst signals periodically and other 3 sensors which arranged on a T-shape Mechanical base receive the 3 dimensional coordinate of these transmitters. After sending 3D coordination data to PC via serial port, a complex and elaborative Visual Basic software calculate the angular dispersion, angular rate acceleration for each also calculate the stabilization parameters among segments such as Al (anchoring index) and cross-correlating between head and trunk coordinates.