A method to estimate the modulation characteristics of the heart rate by autonomic nervous activities has been discussed. The heart rate (HR) and a calibrated instantaneous lung volume (ILV) signal were simultaneously recorded from fourteen healthy male subjects in variety of conditions including the application of autonomic blocking agent. Randomized breathing technique has been introduced to estimate accurately the transfer characteristic from ILV to HR. The spectral analysis of the heart rate together with estimated transfer characteristics from ILV to HR revealed that the respiratory fluctuations in HR are originated from the parasympathetic nervous activity. This result shows the possibility of non invasive estimation of parasympathetic autonomic modulation of the heart rate. The method will provide us of a new method for the characterization of the heart rate variability.

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This report describes effect of facilitation of motor evoked potential (MEP) during application of weak (i. e., below the muscle contraction threshold) electrical stimulation on the peripheral nerve, a process known as Subthreshold Therapeutic Electrical Stimulation (STES). The MEP measurement system consisted of an electrical stimulator, a magnetic stimulator, EMG amplifier, electrical stimulation artifacts eliminator and computer. Magnetic stimulation was applied to the motor cortex using a circular stimulation coil; STES, to the common peroneal nerve using a surface electrode. To avoid electrical stimulation artifacts on MEP, the magnetic-stimulation pulse phase was synchronized with the electrical-stimulation pulse phase by computer on the basis of calculated MEP latency. During application of STES to 6 healthy subjects, MEP was recorded from the anterior tibial muscle using a surface electrode. In increasing of STES level, MEP showed enhanced amplitude in all subjects. Integrated MEP (IMEP) was increased significantly by the application of over 40 [%] levels STES and IMEP was maximized by the application 90 [%] STES. The results of this study demonstrated effect of facilitation of MEP during application of weak electrical stimulation to the peripheral nerve.

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The purpose of this research is to develop a magnetic sensing device for measuring the three dimensional mandibular movement around the intercuspal position of the mandible with high accuracy. Four chip coils are assembled in this device. One of them (a primary coil) is used as a target and is fixed on the buccal surface of the lower first molar, and the other three coils (secondary coils) act as sensors and are fixed on the buccal surface of the opposite upper posterior teeth. A chip coil is a small and light coil; 2.5mm in diameter, 2.0mm in height and 60 mgr in weight. The measuring range of this device is 6×6×8mm and the average of the measurement error after correcting three dimensional distortion is 62μm. From the preliminary experiments, when chip coils were placed into the mouth the output values from the device were influenced by three factors; oral temperature, dental materials (Au-Ag alloy, Au-Pd-Ag alloy) and tilt of the primary coil and secondary ones. As regard to the temperature, the output values at each subject's oral temperature was transformed to the values at room temperature (23.5°C). The influence of dental materials could be eliminated if the distance between coils and dental materials were separated more than 2mm. A small amount of tilt between the primary coil and the secondary coil will occur because the mandibular movement is an ingenious combination of translation and rotation. The measurement error resulting from this tilt was approximately 40μm at the maximum tilt angle 5.9° and this is not substantial enough to disturb the measurement of the physiological movements such as mastication and swallowing. The magnetic sensing device was proven to be capable of measuring the mandibular movements more physiologically than the other measuring tools. It will be possible to make less invasive measurement of jaw movements, especially in the case of children.

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An algorithm for ambulatory measurement system of the human walking is discussed. Based on the variation of the acceleration waveforms at the waist, the proposed algorithm identifies the sort of the gaits, e. g. gaits while walking on a flat floor or going up/down stairs. The procedure of the studied method is as follows: First, several acceleration waveforms for each sort of the gaits are measured, and to get a set of reference waveforms, they are classified using the clustering method. Next, unknown waveforms are compared with the gotten references and are identified. In this paper, we discuss the details of the algorithm and show the experimental results which indicate that the method successfully identifies the sort of the gaits.

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In the analysis of the ERP (event-related potential) the use of the oddball paradigm, single sweep recording of P 3 (P 300, most prominent positive peak in the ERP) is strongly required, bacause the waveform of P 3 may vary from each trial depending on psychological and recording conditions of the subject. As the child ERPs are contaminated with background EEG whose frequency overlaps with the P 3 in the ERP record, neither a single use of a band pass filter nor a mathematical model for the P 3 can not extract the waveform of the single trial P 3. This paper proposed a new method for extracting single trial P 3 in the child ERPs by combinational use of the band pass filter and the mathematical model of the P 3. The model parameters of each waveform were determined so as to minimize the square sums of the modeling errors by using an optimization technique of the Fletcher-Powell method. The proposed method was applied to the ERP data of nine normal children. The features of the P 3 waveforms were appropriately extracted by the use of the proposed method.

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We made a semi-automatic measurement system using a personal computer in which centromeres of specific chromosomes in human tumor cells were labeled by the fluorescence in situ hybridization (FISH), and the number of hybridized parts per nucleus was counted. In order to improve the precision of measurement, as basic data, the measurement was conducted to X chromosomes of normal lymphocytes. We propose a method to set the practical value of distance between adjacent spots; the spots closer than this distance should be considered to one spot.

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