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The combination of transcranial magnetic stimulation (TMS) and electroencephalogram (EEG) is an effective method for investigating the cortical reactivity and the functional connectivity in the brain. This study focused on the measurement of evoked potential induced by TMS and obtaining the topography of the EEG over the whole head. In our past study, the electroencephalograph that removes artifact that has been caused by the magnetic stimulation was developed, and the brain wave evoked by TMS was measured. However, it is difficult either to measure the EEG over the whole head or to obtain the current distribution in the brain. In this study, the EEG over the whole head was able to be measured, and the EEG topography was obtained too. It is possible to measure the evoked EEG after a stimulation at 10 ms. In order to investigate the relationship between the stimulus strength and the evoked potential, the stimulus intensity was changed at 3 levels, motor threshold(MT), 90% of motor threshold, 80% of motor threshold and 70% of motor threshold. The result showed that there seemed to be a relationship between the stimulus intensity and the amplitude of evoked EEG. Topographies of the evoked EEG were obtained after a latency at 30 ms. We also observed the spreading of the EEG response to the contralateral hemisphere. It is possible to consider that the evoked signal by TMS to the motor area was conducted to contralateral hemisphere along the corpus callosum.

In orthopaedics, quantitative assessment of dynamic knee kinematics under in vivo conditions is very important for understanding the effects of joint diseases, dysfunction and for evaluating the outcome of surgical procedures. This study presents a method to determine 3D kinematics of normal knee using X-ray fluoroscopy. 3D poses of normal knee are estimated using a feature-based 2D/3D registration technique, which uses bone contours on fluoroscopic images and 3D bone polygonal surface model of femur, tibia/fibula, and patella. The 3D bone models for each normal knee were created using CT scan data from a single subject. An objective function is defined as the sum of Euclidean distance from point on the projection rays (corresponding to the point on the contours) to the closest point on the bone model surface. The 3D pose of the bone model is estimated by minimizing the objective function iteratively with a non-linear optimization technique. In the 3D kinematic analsysis of normal knee, the relative pose of the femur with respect to tibia/fibura was determined by employing a three-axis Euler-angle system. In order to validate the pose estimation accuracy of normal knee, computer simulation test was performed. A set of 5 synthetic silhouette images was created for each bone model in known typical orientations. Errors in the 3D pose of the model were determined by comparing the estimated pose to the known pose. The result of computer simulation test showed that the root mean square errors were within 1.0mm, 1.0°except for out-of-plane translation for femur, tibia/fibula. While, for patella, rotation errors were increased. In clinical application, dynamic movement under loaded conditions was test. The result of knee kinematics showed a smooth and reasonable physiologic pattern, and the reliability and feasibility of present method was demonstrated.

Mechanomyogram (MMG) can evaluate the mechanical function of the muscle. The MMG is generally measured using the accelerometer and it is known that the amplitude of acceleration MMG (MMGg) decreases during tetanic contraction. In this study, the displacement MMG (MMGd) in tetanic contraction was measured using a laser displacement sensor, and the relationship among the contraction force, the MMGg and MMGd was discussed. And the contraction properties of different muscle fibers in tetanic contraction were also discussed. The tibial nerve of rat was electro-stimulated, and the isometric contraction of gastrocnemius and the soleus muscle were induced as the foot was fixed. The electro-stimulation was repeatedly done at (1) 2–100 [Hz] and had stimulation period in 1 [s] and idle period in 1

Information regarding to eye movement is applied to many fields such as psychology, ophthalmology, physiology, rehabilitation medicine, web design and human-machine interface. So far many technologies have been developed to detect the eye movement and most widely used techniques include EOG (electro-oculograph), Purkinje image tracker, scleral search coil technique, VOG (video-oculograph). This study aims at development of algorithms that can detect and track the gazing point by comparing the relative coordinates of the center of a pupil in the eye image acquired by a CCD camera and image grabber and the center of the four infra-red reference points image reflected from the eye. The size of input image was scaled down to 1/16 to detect the eye and its neighbor areas quickly. An approximative eye position is calculated from this scaled-down image for the detection of precise position of the center of pupil and four reference points reflected from the eye. These four reference points are created by infra-red illumination not to disturb subject’s attention to the target. The infra-red lamps were turned on for the time duration of one frame of image and turned off for the next one frame so that the four reference points reflected from the eye could be extracted easily by comparing these two images. The theorem for a circumcenter of a triangle was applied to detect the center of pupil. The gazing point could be calculated by the relative distance and angle between the center of pupil and the center of four reference points in the captured image.

This study aims to establish an electronic wheelchair system in Taiwan that conforms to multiple master multiple slave (M3S) standards. The proposed system could enhance the safety and convenience of people with disabilities.

The purpose of this study is to determine distributions of local plantar shear stress and pressure in diabetic foot patients during walking. Twelve normal subjects who have no surgical history of foot problems in foot and three diabetic foot patients with diabetic neuropathy in the lateral heel participated in the study. An insole-type local shear stress sensor was developed, and both mediolateral and anteroposterior components of local shear stress were measured during level walking. Results showed that shear stress in the lateral heel for diabetic foot patients was relatively smaller than that in the normal. For diabetic foot patients, significantly larger shear stress in the medial direction was observed at the 2nd metatarsal head in pre-swing, comparing with the normal. Anteroposterior shear stress in diabetic foot patients became significantly smaller at the 4th metatarsal head in pre-swing than that in the normal. For patients who had diabetic neuropathy in the lateral heel, the center of pressure started from the medial heel and then moved linearly toward 1st or 2nd metatarsal head. Diabetic foot patients showed relatively smaller pressure in the 2nd metatasal head and the hallux in pre-swing than the normal subjects. Results showed that local shear stress distribution correlated very well with the pressure distribution. Further study with patients of different foot problems would be very helpful to design corresponding foot orthoses.

In these days, various foot problems have been rapidly increasing. Hallux valgus(HV), one of the most popular foot diseases, is found especially in mid-aged women. The most common cause of HV is to wear with small and pointed shoes for a long time. If HV is left untreated, the deformity in the other regions of the foot also follows. Even though many motion analyses and radiologic studies have been applied to various foot diseases, they do not provide quantitative information on the detailed motion of the foot. The purpose of this study is to analyze detailed foot motions of the normal and HV patients using a multi-segment foot model. Ten healthy adults, who have no disorders in the lower extremity, participated in three dimensional gait analysis. Twelve HV patients of Grade 2 were also chosen for the study. Results showed that HV patients exhibited relatively smaller flexion/extension, especially in terminal stance. An early abduction at the ankle during terminal stance was also noted in HV patients, which resulted in an excessive abduction in subtalar joint. In HV patients, medial MP joints exhibited excessive amount of adduction during terminal stance. In HV patients, hallux MP joint and talocrural joint exhibited excessive external rotation over the whole period of gait cycle. Understanding the detailed foot motions by the present multi-segment foot model would be very useful to diagnose and to treat patients with various foot diseases, and helpful for the design of foot orthoses.

In this study, we present a novel technique to evaluate in vivo femorotbial contact in total knee arthroplasty (TKA) during dynamic motion. Knowledge of joint contact and its area in TKA during dynamic motion could not only provide kinematic information dependent on articular shape but also assist in improving the design of TKA that include tibial polyethylene insert. In previous studies, joint contact in TKA has been evaluated using pressure sensitive film or digital tactile sensor. However these techniques are limited because they are only able to operate under static in vitro or quasi-dynamic conditions, and cannot be physically applied to TKA patients under dynamic in vivo conditions. To materialize evaluation of femorotibial contact under dynamic in vivo conditions, we employ a computer vision technique called 2D/3D registration, which estimate the 3D pose of radiopaque metallic femoral and tibal components using X-ray fluoroscopic image and computer-aided design (CAD) model of the implant. Although the polyethylene insert is radiolucent and does not appear on fluoroscopic image, in fixed-bearing TKA, the insert can be assumed to be fixed on the tibial tray. Therefore, the 3D pose of the insert can be easily determined, as the pose of tibial component was estimated. To visualize and quantify femorotibial contact, the proximity between surfaces of femoral component and insert is calculated, and mapped onto the insert surface model. The femorotibial contact was visualized and quantified as the region on the insert surface where the proximity is less than 0.5 mm threshold, and the threshold value was determined from the result of 3D pose estimation accuracy by phantom experiments. In clinical applications, the evaluation of femorotibial contact was performed using images from a fixed-bearing TKA patient during dynamic motion. Dynamic states of the contact were visualized and quantified including axial rotation and unilateral loading during knee flexion, and post-cam contact of posterior stabilized TKA. The present technique provided us new information and enabled us to better understand or predict the location, translation and size of the contact region during in vivo dynamic motion.

The adequate treatment of the patients with moderate to severe mixed hearing loss (MHL) is not sufficiently possible with conventional hearing aids. These patients have enough cochlear reserve, but the additional middle ear disorder limits the usage of conventional hearing aids (gain limitation and distortion). The second possibility for such patients would be the bone conduction hearing aids, which indicate an insufficient gain for moderate to severe MHL. On the other hand because of good cochlear reserve there isn’t an indication for cochlear implantation. Therefore there is no optimal way to give an adequate gain to patients with moderate to severe MHL.

The new improved DACS-system (Direct Acoustic Cochlear Stimulation) realizes a direct transfer to the inner ear. In this way the conductive disorders of middle ear does not have any influence on the sound transfer. After an introduction of the functional principle of the system the pre- and postoperative audiological results of 4 implanted patients will be presented in this paper. The one year post operative results indicate a functional gain of about 50 dB HL and an SRT (Speech Reception Threshold) improvement of about 40 dB SPL.

The method of residual strain application in numerical analysis was proposed. Then the residual strain was added to finite element model of blood vessel segment as an initial condition. The significative results were obtained and we drew some conclusion.