Edmond Lou

A wearable computer for physiotherapeutic scoliosis treatment

A posture monitoring system for the treatment of idiopathic scoliosis using electromagnetic and accelerometer technology is discussed. Distributed processors are used to allow parallel execution of data collection. The system is carried by the patient and provides feedback to allow correction of posture during daily activities.

A low-power posture measurement system for the treatment of scoliosis

A battery-powered electromagnetic (EM) system has been developed to measure topographical features of the trunks of patients with scoliosis. The system includes an EM measurement system and a data acquisition system. The system resolution and accuracy are 0.25 cm in the range of 15-30 cm. The entire system can be carried by scoliotic patients during daily activities. The dimensions of the system are 10 cm/spl times/14 cm/spl times/4 cm and its weight is 100 g. A patients posture can be evaluated in real time so that appropriate feedback can be provided to correct his/her posture.

An electronically integrated load cell [for monitoring pressures of orthotic braces]

An electronically integrated strain-gauge load cell has been developed for monitoring pressures between orthotic braces and the human body for adolescents who have spinal deformities. This load cell has a built in amplifier and low-pass filter. High signal-to-noise ratio, temperature compensation, low power consumption and cost effectiveness are the major advantages of this design. The maximum load for this cell is 110 cm of water (approximately 20 N). Laboratory tests have established that the nonlinearity and hysteresis are less than /spl plusmn/2.5%, and the signal to noise ratio is greater than 70 dB. This paper describes both the structure and the operational principles of the load cell, and presents the calibration results.

Broadband ultrasound attenuation measurement of long bone using peak frequency of the echoes

The traditional peak frequency formulation requires the knowledge of the signal wavelet. We improved and applied the method to estimate attenuation for homogeneous silicon rubber and bovine cortical bone without recourse to the wavelet assumption. The estimated values for rubber and bone samples are 6.59 plusmn 0.28 dB/MHz/cm and 4.59 plusmn 1.09 dB/MHz/cm, respectively, as compared with 6.33 plusmn 0.19 dB/ MHz/cm and 5.00 plusmn 1.10 dB/MHz/cm, respectively, by the spectral ratio method.

A system for measuring pressures exerted by braces in the treatment of scoliosis

A battery-powered microcomputer system has been developed to continuously monitor pressures exerted by braces used to treat children with spinal deformities. Data are collected using an analog system with 16 transducers to measure either brace pressures or strap forces. Data acquisition is controlled by an MC68HC11 microcontroller. CMOS circuits are used to minimize power consumption, and the microcomputer and analog circuitry are kept in a low-power operating mode, except at the specific times when the measurements are taken. A programmable real-time clock controls the sample time and interval, and provides an interrupt to awaken the microcomputer from its low-power sleep mode. Data can be sampled with intervals ranging from 1 s to 1 day with the duration from 2.5 h to 2 weeks. At the end of each study, the data are transmitted to a host computer for analysis. Optimal use of all the features of the MC68HC11 enabled a system to be made which is small, lightweight, robust, and can be mounted on a brace worn by a child. Initial clinical studies suggest that mean brace pressures vary from 67 to 139 mmHg in the frontal plane and from 17 to 66 mmHg in the sagittal plane, and mean strap forces vary from 45 to 90 N. >

An intelligent active brace system for the treatment of scoliosis

Efficiency of brace treatment for adolescent idiopathic scoliosis is correlated to how the brace has been worn. The more often the patients wear their braces to the prescribed tightness as well as to the prescribed length of time each day, the better the treatment outcomes. This paper describes an active intelligent brace system designed to maintain the interface pressure between the brace and body within the prescribed range during daily activity. The intelligent system consists of a microcomputer, a force transducer and a force feedback component. A subject who has no scoliosis volunteered to test the system for a few hours. Preliminary trials indicate that wearing the system increases the amount of time which a subject wears his brace in the prescribed range of tightness. The test subject wore the brace without feedback within the prescribed range of tightness for 28% of the time, whereas when the air bladder feedback system was activated, the subject wore the brace effectively for 47% of the time.

A High-Load Stress Sensor for Scoliosis Surgery Application

The design of a stress sensor for a scoliosis surgery application is presented. Designed specifically for detecting forces and moments placed on spinal hooks and screws used in scoliosis correction, the sensor is less 2mm in the largest dimension and less than 0.5mm in thickness. The operative range is approximately 1000MPa in shear and normal stress directions. Preliminary FEA simulation of a piezoresistive sensor incorporating these design constraints demonstrates that different output signals are produced as the sensor is subjected to shear and normal stresses. When the separate signal patterns from several sensors are combined, the hooks and screws will be able to resolve forces and moments in three dimensions.

A low power portable electromagnetic posture monitoring system [for scoliosis treatment]

A posture monitoring system for the treatment of idiopathic scoliosis using electromagnetic and accelerometer technology is discussed. Distributed processors are used to allow parallel execution of data collection. The system is carried by the patient and provides feedback to allow correction of posture during daily activities.

A Wireless Load Measurement Tool for Spine Surgery

Comprehensively understanding the mechanics of loads transmitted to the spine during scoliosis corrective surgery will improve surgical outcome and patient safety. A system consisting of wireless instrumented hooks and screws, and a wireless data acquisition system was developed to measure the loads and moments imposed during scoliosis surgery. From laboratory tests, the maximum error of posterior/anterior forces and moments were 2-3% of the maximum loads during surgery. This study improves the understanding of mechanics during surgical correction

A posture measurement system for the treatment of scoliosis

A battery-powered posture measurement system has been developed to monitor the topographical features of a scoliotic trunk. The system consists of an electromagnetic measurement system and a microcomputer data acquisition system. The polar coordinates of up to 8 receivers relative to the transmitter can be determined. Laboratory tests showed that the maximum distance error was 0.5 cm and the maximum angle error was 5 degrees in the range of 30 to 47 cm. This system is applied to help adolescents who have scoliosis attain a more balanced posture with the use of feedback preliminary clinical trials were done and showed that the system was able to detect the postural changes.