This study focused on the estimation of muscle force developed by electrical stimulation to evaluate muscle fatigue during FES control. Muscle force, M-wave, and oxygenated hemoglobin and deoxygenated hemoglobin levels in a muscle were measured simultaneously under isometric conditions during electrical stimulation with three neurologically intact subjects. The oxygen consumption rate was estimated from the measured hemoglobin levels. Electrical current stimulation with 20Hz of frequency and 0.3ms of pulse width was applied to the right vastus lateralis muscle through surface electrodes. Stimulus pulse amplitude patterns were (a) long-term constant stimulation (increase for 10s and maximum for 590s) and (b) repetition of short-term constant stimulation (increase for 10s and maximum for 50s) with 10s interval (intermittent stimulation). The M-wave amplitude and the oxygen consumption rate were approximated to muscle force by the first-order linear equation, using the least-squares method. The results showed that the M-wave would be effective for muscle force estimation before severe muscle fatigue. The M-wave was also found to be useful in predicting muscle force decrease caused by muscle fatigue. As for the oxygen consumption rate, it was suggested that the rate would be useful for muscle force estimation during long-term stimulation, excluding the beginning of the stimulation. The reasons why the M-wave amplitude varied unstably when electrical stimulation was applied continuously more than 200s and why the oxygen consumption rate was delayed from muscle force at the beginning of the first stimulation must be clarified.

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Using MR head images, we extracted the characteristics of Alzheimer-type dementia (ATD) from images and calculated diagnostic parameters and examined whether they would be useful for a distinction of normal elderly subjects (control) and ATD patients. Furthermore, we aimed at examining a possibility that the degree of ATD severity can be evaluated objectively by the use of diagnostic parameters. A significant difference existed between the control group and the ATD patient group in the calculated parameters, and it was suggested that each parameter is useful for the diagnosis of ATD. Moreover, the sensitivity and specificity of the combination of HIR (Hippocampus Intracranial Ratio) with VIR (Ventricle Intracranial Ratio) were 87.8% and 92.7%. Furthermore, as a result of performed multiple discriminant analysis for the degree of ATD severity after a discriminant analysis of control and ATD patients, the possibility of an objective evaluation of the degree of ATD severity was suggested.

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Blood tests are widely carried out to screen for various diseases. However, this kind of test causes physical and mental stress for the subjects. The authors aim to develop a semi-invasive blood-collecting needle that needs no power source for the pump mechanism. In this study we fabricated a capillary action needle that can automatically collect a blood sample. This needle has a half-open crevice in the tip. For the physical characteristics of the blood-collecting needle to be evaluated, the relationship between the size and the suction time and/or suction volume were measured by use of an isotonic sodium chloride solution, whole rabbit blood, and whole human blood. Next, to evaluate the degree of invasion, the diameters of erythema in the auricles of rabbits were measured. As a result, the selection of the correct size of blood-collecting needle enabled the collection of 0.1μL of whole human blood in 10 seconds. Moreover, by a comparison of the observed diameters of the erythemas, it was shown that the invasiveness of the blood-collecting needle was smaller than with commercial needles. It thus became clear that this fulfills the fundamental functions of a semi-invasive blood-collecting needle.

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This paper presents a wavelet-based method for the edge enhancement of medical images. In the proposed method, a novel transfer function is introduced for weighting wavelet coefficients when multiresolution levels and absolute values of the wavelet coefficients are low and great, respectively, thereby resulting in edge enhancement. A Fourier transform method, a conventional wavelet-based method that used a simple transfer function, and our proposed method were compared. These methods were applied to two chest radiographic images. As a result, the proposed method could enhance the edges of the ribs, bronchus, and pulmonary vessels without a significant enhancement of noise in comparison with the Fourier transform and conventional methods.

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This paper describes how to detect the P300 component of event-related potentials (ERPs) in the consideration of individual differences. P300 appears as a result of interesting stimulus for a subject and can be used to detect its attention. In this study, the subjects were asked to choose one target word from five that were randomly presented. These methods were used for detecting P300: (1) band-pass filtering of ERP components around a central frequency (e. g., 3Hz); (2) an average of 20 single-trial responses to each stimulus; (3) subtraction of the common components in ERP responses to target and nontarget stimuli; and (4) cutting out of P300 with a trapezoidal time window. It is very important to use suitable experimental parameters for each subject to improve the rate of judgment. The experimental parameters we used: (a) central frequency of band-pass filtering; (b) the number of averaging; (c) position of trapezoidal time window; and (d) width of trapezoidal time window. The experimental results demonstrated that it is possible to construct a more practical communication aid for patients of amyotrophic lateral sclerosis when the experimental parameters are optimized for each patient.

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