The spine has the 32-33 vertebras that are connected by intervertebral discs and ligaments, etc. and plays important roles to maintain the protection of nervous system and the smooth transmission of external impact. Various researches on the experimental approach with a pressure sensor etc. and the simulation research on the finite element method etc. have been performed for the spine in response to remarkable advancement of biomechanics in the field of the orthopedics. However, although the intervertebral disc is important for the composition of the spine, basic characteristics of the deformation behavior of the intervertebral disc are not understood enough yet. And it is well known that the disc is sometimes damaged when we are exercising. In this research, the focus was applied to an intervertebral disc as a measurement target, and deformation behavior of an intervertebral disc was measured by Electronic Speckle Pattern Interferometry (ESPI) under compressive load in a condition which connected with body of vertebra composed of three intervertebral discs and four vertebral bodies of the fresh cow. The displacement measurement by ESPI was enabled with preprocessing by spraying minute particles after oily varnish had been over the chest vertebra. Results indicate that when the spine was compressed, large strain was obtained at the position around pulpy nucleus of the central part of the intervertebral disc. And the load as the reaction force of a spine decreases according to time process when the displacement load to the spine is maintained constant. Moreover, the strain generated in the intervertebral disc and the body of vertebra also showed the tendency to decrease as time passed.
Elasticity imaging of soft tissue with contact impedance method was performed to quantify medical palpation. Frequency changes of piezoelectric vibrator in contact with soft tissue depends on the elastic modulus of materials. This technique is called “Contact Impedance Method”. Frequency changes of tumor model made by silicone rubber were measured with this system. It was shown that we could detect the tumor under normal tissue that couldn't be detected by stress-strain curve with this method. In order to clarify the mechanism of tumor detection, we calculated the equivalent mass area that decreases frequency. These results suggested a possibility of quantification of medical palpation with elastic modulus imaging of large area. The method can be used for quantitative diagnosing method of disease state.
This paper describes bio-signal measurement of a patient being transferred by a stretcher. The medical accidents during the transferring are reported because in the transferring, the bio-signal of the patient is hardly measurable and abrupt changes in the physical condition are hardly detected. The measurement must be unstrained and non-invasive because the quick transferring is required. Just after lying on the stretcher, bio-signal must be measured without any operation. This paper presents a completely non-invasive measurement based on the pneumatic method. Use of the pneumatics guarantees the non-invasiveness even of the static electricity and micro-wave. However, the method detects the bio-signal from very small pressure change and thus is very sensitive not only to the bio-signals but also the mechanical vibration noises which occurs during transferring. Here we present several noise cancellation and reduction methods and show a robust method to measure respiration and respiratory arrest condition. Experiments in various situations show validity of the method.
Sleeping has a significant role in refreshing the brain and body from fatigue. Due to the aging, however, obtaining the sleep of high quality gradually becomes difficult. In Japan, which now faces the problem of aging society, it is important to promote the maintenance and enhancement of the health by securing the sleep of high quality. For that end, unconstrained monitoring of sleeping conditions on a daily basis is expected to be helpful. In this study, comb filters were applied to bio-signal obtained by pneumatic method to extract with high accuracy the heartbeats and the body movements, which then were used to define an index that shows the condition of a REM sleep and another that shows the depth of a sleep. Also determined was a function used for obtaining the incidence ratio and the standard deviation of the extracted elements for each sleep stage. The function was determined for each age-group. Using these indices and the functions, an algorithm to surmise the sleeping stage of a subject was proposed. The mean rate of agreement between sleep stage categorized into 6 sleep stages or 5 sleep stages or 3 sleep stages determined by the proposed method and that by the R-K method, the world standard method, were 51.6%, 56.2% and 77.5%. Mean of kappa statistics were 0.29, 0.39 and 0.48, respectively.