Magnetoelastic skin curvature sensor for biomedical applications

The present paper concerns the versatile applicability of a novel skin curvature sensor family for multiparametric monitoring of physiological parameters. The basic element of the sensor is a magnetoelastic bilayer which shows a magnetoelastic amorphous layer and a nonmagnetic layer. Bending the bilayer causes the magnetoelastic layer to experience either tensile or compressive stress, depending on the direction of bending. The resulting large changes of magnetic permeability can be measured using a coil. The extreme thinness of the sensor favors its application on the skin in various medical diagnostic areas. On the neck and on the chest wall, the sensor registers cardiorespiratory activity and interrupted breathing, both being relevant for the so-called sleep apnea syndrome. Registration of leg movements is demonstrated on the calf for the diagnosis of the restless leg syndrome. Assessment of eye movements is shown using a miniature sensor version.