| Summary: | 博士 === 國立成功大學 === 醫學工程研究所碩博士班 === 92 === Foot architecture is very important for standing and walking. Abnormality is expected to result in balance dysfunction because of inappropriate somatosensory inputs. For geometric study, footprint analysis is a non-radiation and better viable one- and two-dimensional method for clinical assessment of the medial longitudinal arch of the foot compared to the X-ray approach, but lack of automatic and efficient tool for measurement. For functional survey, monitoring central of pressure (COP) under Sensory Organization Test is a good way to evaluate postural control ability.
In this study, we have designed a system integrating the function of digital footprint acquisition, foot arch reconstruction, and virtual reality (VR) balance evaluation. It is a portable platform consists of a digital camera and two pieces of glass, which has load cells under each corner. When the subject stands still on the transparent force plates, the digital camera is triggered, photographing the soles of the feet at the moment when both feet bear approximately at the same weight for 3 seconds. Blue water is placed between the foot and the force plate to enhance the contrast between sole and background. Contour and several parameters of footprint are acquired by image analysis techniques. Besides, by a stair with known height in each step and adding a white elastic membrane on the box, the three-dimensional (3D) structure of the arch can be reconstructed based on the relationship between the brightness of the image and the depth of the water, which can provide more representative information than a conventional ink footprint with its low resolution and easy smearing. Furthermore, with force plate, the system is also able to record the sequential changes of COP during still standing under different somatosensory and VR visual conflict conditions and derive several parameters for the balance function evaluation.
It is well investigated in the impact of the neurological impairment on the postural control. However, little attention had been paid to the role of the bony alignment for the balance. Hence we collected the footprint image and sequential changes of COP in different SOT conditions from 65 children of a kindergarten and elementary school. As the result, the arch height is significantly negatively related with the postural control ability while standing under somatosensory and visual conflict for the children aged 4-5 years, whose neurological system are under developed.
It is expected that this system could provide a reliable quantitative approach for 2D footprint analysis, 3D surface reconstruction of the sole under weight-bearing condition for further understanding the characteristics of the arches and insole fabrication with computer-aided-design computer-aided-manufacture (CAD-CAM) technique, and evaluation of the standing postural control ability
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