Wearable Lumbar-Motion Monitoring Device with Stretchable Strain Sensors

Abstract

Low-back pain is a common affliction. Epidemiological analyses have reported that periodic cycles of lumbar flexion and rotation are major risk factors for low-back pain. To prevent low-back pain, a lumbar-motion monitoring device could help diagnosticians assess patients’ risk for low-back pain. This study proposes such a device that uses lightweight stretchable strain sensors. Six of these strain sensors form a parallel-sensor mechanism that measures rotation angles of lumbar motion in three axes. The parallel-sensor mechanism calculates rotation angles from the lengths of the strain sensors iteratively. Experimental results reveal that the prototype device is effective for lumbar-motion measurement and significantly improves in terms of wearability over comparable devices.

A Comprehensive Review on the Optical Micro-Electromechanical Sensors for the Biomedical Application

“…In such cases, detection of the wrong posture could give major advantages. Many wearable devices had been investigated for different applications, wherein the sensitivity of the sensor achieved as high as 0.2 nm/με −1 ( 60 , 61 ).…”

Wearable Detection of Trunk Flexions: Capacitive Elastomeric Sensors Compared to Inertial Sensors

“…They are obtained from an elastomeric insulating layer (e.g., made of a silicone rubber) sandwiched between two layers of a deformable electrode material (e.g., a carbon black-loaded silicone rubber), so as to assemble a stretchable capacitor. By arranging a set of these sensors such that they are stretched by specific postures and movements, following a calibration it is possible to relate occurring variations of capacitance to thee motions of body segments, as shown by several studies [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].…”

“…The implementation of a calibration strategy that avoids the limitations of typical approaches reported in the literature, such as measuring the angles with bulky, unpractical, and/or expensive external equipment (e.g., stereophotogrammetry [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ]), or using interpolations of data captured from reference poses (which enables pose recognitions but does not provide accurate measurements of angles [ 26 , 27 , 28 ]).…”

Monitoring Flexions and Torsions of the Trunk via Gyroscope-Calibrated Capacitive Elastomeric Wearable Sensors

“…They are made of an elastomeric (e.g., silicone made) insulating membrane, sandwiched between two elastomeric conductive layers (e.g., made of a carbon black-silicone composite), acting as soft electrodes, so as to obtain a deformable capacitor. By using them as wearable sensors, it is possible, following a calibration, to relate variations of capacitances to changes in postures, as shown by various investigations [22][23][24][25][26][27][28][29][30][31].…”

“…(i) the demonstration of a strategy to calibrate the system for flexions and torsions, avoiding the limitations of typical solutions described in the literature, such as an-gular measurements with bulky, unpractical and/or expensive external equipment (e.g., stereophotogrammetry [22][23][24][25][26][27][28]), or pose recognitions via interpolations of data acquired from reference poses, which however do not provide accurate angular measurements [29][30][31]; to that aim, in this study, we used a wearable three-axial gyroscope; (ii) a comparison of the sensing accuracy of a new wearable system in measuring both flexions and torsions, relative to conventional stereophotogrammetry (as the nonwearable standard technology).…”