A new apparatus for measuring the motion of the shoulder complex has been developed. The system is composed of four portions, i. e., a mechanism part which consists of a gimbal and a sliding free arm with three optical rotary encoders, a counter circuit which decodes the outputs of the rotary encoders, a personal computer system and two holding gears for the subject's trunk and elbow. The loci of the end of the free arm, which are mapped on each of the horizontal plane, the sagittal plane and the frontal plane of the subject, are displayed on real time. The apparatus has abilities in calculating conventional ranges of motion of the shoulder complex. In addition, a concept of the three-dimensional range of the motion (3D ROM) of the shoulder is introduced. This index is defined as the area which is enclosed by the path of the maximum motion described on a sphere, the center of which corresponds to the shoulder joint. The 3D ROM observed from any viewpoint can be displayed. Moreover, another index of the three-dimensional percent range of the motion (3D% ROM), which is defined as a percent ratio of the whole spherical surface to the 3D ROM, quantitatively explains a three-dimensional mobility of the shoulder complex. As a result of experiments on 19 persons, involving 3 patients using the apparatus, the normal value of the 3D% ROM has been found to exceed the range of 40%.

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A battery-type automatic defibrillator with temporary pacing function has been developed. The pacing function is activated after defibrillation to work as a high-output ventricular demand pacemaker. To minimize the number of circuit devices and battery size, the output circuit of the implantable defibrillator, which has been developed by our group using a gate turn-off thyristor, has been improved and a small size oscillator has been added to the pacing circuit for the defibrillator. Moreover, the residual energy in the output capacitor has been used after the defibrillation for the high-output pacing.
The developed system has been tested in animal experiments. Three mongrel dogs were anesthetized with pentobarbital and mechanically ventilated. After thoracotomy, a catheter type blood pressure sensor was inserted into the right ventricle through the right auricle, and a catheter, which has two electrodes made of stainless steel (surface area of 260mm² and 100mm apart), was introduced through a jugular vein into the apex of the right ventricle. The catheter was used for both defibrillation and pacing.
In the animal experiments, fibrillation was electrically induced, and the automatic defibrillation and pacing function were confirmed. After defibrillation, as the high-voltage converter did not work during the pacing, the capacitor voltage in the defibrillator decreased exponentially. However, it was possible to continue the fixed-rate pacing (60ppm) for more than three minutes after defibrillation. The main reason for the decreasing voltage was due to the voltage measuring resistor (1MΩ), connected to the capacitor in parallel. The pacing pulse was inhibited during sinus rhythm using blood pressure signal.
From the results, it was possible to accomplish pacing function using residual energy after defibrillation by improvement and addition of the circuit in the defibrillator.

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Relations between the excitation fronts propagating in the heart and the equivalent dipoles estimated from the body surface potential distributions have been investigated by means of the computer simulation. The equivalent dipoles are determined either by minimizing the square deviation between the measured potential distribution and that generated from the dipoles or by comparing them through their multipole expansion coefficients. These two methods, that will be called the direct and the indirect methods, respectively, were compared in the single moving dipole (SMD) approximation. Furthermore, the direct method was applied to the two-moving dipole (TMD) approximation.
Simulations were performed in the following way: At first, the propagation processes of the excitation fronts were simulated on the three-dimensional heart model composed of 125000 unit cells, to each of which can be assigned different action potential waveform. Next, the body surface potential distributions generated by the resultant EMF sources in the heart were calculated. Then, the equivalent dipole method was applied to them, and the dipole locations thus obtained were compared with the mean locations of the excitation fronts. Since the EMF sources are distributed on the excitation front as an electric double layer, its periphery rather than the shape of the excitation front itself is essential in determining the potential distribution. Hence, the mean location of an excitation front is defined as the gravitational center of its periphery.
When there is a single excitation front with simple shape, the equivalent dipole location obtained from the SMD approximation coincides with the mean location of the excitation front. The coincidence is better with the direct method, but it needs longer calculation time than the indirect method. Through 25 to 30ms after the onset of the ventricular depolarization, the excitation fronts have complicated shapes and the deviations of the equivalent dipole locations from their mean locations become large even if the TMD approximation is used.
Except the early and the last stages of the ventricular depolarization, there are usually a dominant excitation front and smaller ones. One of the equivalent dipoles resulting from the TMD approximation is located near the mean location of the largest excitation front, and the other has a tendency to be located around the center of small excitation fronts.

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Recently, quantitative infrared thermography has become important. Many attempts have been made to obtain quantitative information about the pathophysiological phenomena from the thermograms. We have developed a synchronous thermographic system and have tried quantitative analysis of the peripheral circulation using this system. In the present paper, the details of the newly developed synchronous thermographic system are first described. Secondly, examples of quantitative analysis of the thermograms by using signal processing methods are shown. Our system consists of an infrared camera, a synchronizing circuit for controlling the mechanical scanning of the camera, a telemetry ECG system, a high-speed frame memory unit of our own making (512×512×16bit), a microcomputer system and a floppy disk unit. We can take thermograms every 10 seconds in succession and store them in real time. In the phase locked mode, we can measure time sequential skin temperature data without the influence of the trivial variation of the skin temperature due to the periodic blood flow. In the sampling mode, we can observe the time course change of the peripheral circulation within one cycle of the heart beat. Applying the Maximum Entropy Spectrum Analysis to these time sequential clinical thermograms, we may quantitatively estimate transient pathophysiological phenomena. Here, we use the ECG signal for the synchronizing signal of the camera. We can also use other signals, for example, respiration, etc. for the synchronizing signal.

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Intrapartum fetal condition can be more easily observed by means of trendgram which is composed of fetal heart rate (FHR) and uterine contraction (UC) parameters. Usefulness of trendgram has been investigated in serial preliminary studies before the establishment of final system of automated trendgram.
In the initial study, the trendgram was manually processed utilizing parameters obtained by a microcomputerized FHR analyser TOITU MT-140. Fetal distress index (FDI), FHR score, , uterine contraction (UC) area and FHR-baseline variability seemed useful in the trendgram. By using FHR-trendgram, fetal distress could be diagnosed and differentiated from normal cases. Besides, the cause of fetal distress was suggested, for example, by uteroplacental insufficiency due to severe gestosis or excessively strong contraction.
In the second trial, FHR-trendgram was automatically processed retrospectively after fetal monitoring by use of an 8-bit general purpose microcomputer. The trendgram was also useful to differentiate fetal distress from the normal state using the 4 parameters.
Finally, the FHR-trendgram is indicated on color CRT display with the use of a microcomputer system. Seven parameters (FDI, FHR score, FHR-baseline, variability amplitude, UC area, lag-time and number of dips) based on automated FHR analysis are used in the current FHR-trendgram. The trendgram is displayed for 1, 3 or 5-hour time span through intrapartum stage. Lately, original 15-minutes cardiotocogram and automatic diagnosis can be displayed on the screen by pressing a key on the keyboard. Not only the fetal distress is diagnosed, but also its possible cause is obtained by FHR-trendgram, and then immediate and appropriate fetal distress treatment are applied. FHR-trendgram is one of the ultimate techniques for intrapartum fetal monitoring.

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The author has developed the measuring-walkway for temporal and distance factors, and has made use of the system to perform some analyses of the normal gait.
In this study, the normal child gait analysis has been performed successively. Firstly, the basic statistics of state variable were obtained from 109 5-year-old children. Secondly, the changes in the gait patterns according to gait velocity were analyzed on 29 children of 5 and 6 years old. And thirdly, the development of the gait patterns according to child's ages was analyzed with respect to 75 children aged 1 to 6.
The main results in this study are as follows,
1. In the child gait, the right and left differences, and the sex differences were not observed, though they were typically observed in the adult gait.
2. In contrast with the adult gait, the swing time ratio is large in the child gait. And it shows a tendency to decrease according to years.
3. The coefficients of variation of the child gait are larger than those of the adult gait by about 2 to 10 times, however, they decrease according to ages.
4. As the gait velocity increases, the step length increases curvilinearly, whereas the cadence increases linearly.
5. In children, no fixed relationship exist between step length and cadence, regardless of increased or decreased walking speed.
6. According to years, step length, single and double support duration, any velocity increase while cadence decreases.
7. An increase in step length with age is due to an increase in height. And the value of (step length)/(body height) remains constant independently of age.

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Since a tissue has a volume, it should be characterized not only by qualitative but also by quantitative information. This paper discusses a three-dimensional (3D) display of a tissue, which is displayed together with the ultrasonogram of any specified crosssection. A 3D scanner and the imaging system have been developed so that they may yield spacially enough uniform 3D echo data of a tissue. A spiral scan is newly employed here by which a probe can be rotated in a spiral fashion. The spirally scanned echo data are stored in a disc and are easily accessible because of the easiness of the coordinate conversion. In this manner the corresponding echoes of any plane can be collected fast for the reconstruction of an ultrasonogram.
The 3D image in this system consists of a number of contour images of cross sections which are overlayed with gradated intensities of gray-scale. The 3D technique is also used for a volume measurement. The specified-plane ultrasonogram, on the other hand, is displayed in pseudo colors and is again overlayed on the black and white 3D contour image. Using the two- and three-dimensional images, the positional relation between a plane and the total shape can be observed clearly, when the location of a crosssection is changed little by little.
The system is currently applied to ophthalmic region and some experimental results are also reported.

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Geometrical optical illusion quantities for five famous illusion figures were psychophysically measured when stimulus conditions for subjects were controlled as follows;
(1) Visual fields of subjects were effectively restricted to small area in the central part of the retina using the television eye camera system.
(2) Illusion figures were presented on the peripheral part of subject's retina.
(3) Illusion figures were also instantaneously presented to subjects at very small time intervals.
Results obtained in these experiments showed the points cited below.
(1) Geometrical optical illusion quantities are consistent whether stimuli are simultaneously or successively received by subject's retina.
(2) Geometrical optical illusion quantities increase when stimuli are presented on the peripheral part of retina.
(3) And geometrical optical illusion quantities are consistent even if the presentation time intervals of the stimuli are shortened to very small values.
These data mentioned above do not always correspond to so-called field theories and neural network models of the lateral inhibition or the receptive field for the geometrical optical illusion phenomena.
It is concluded in this paper that a mechanism of generation of the geometrical optical illusion phenomena is not expressed as a function of simultaneous process in the peripheral nervous system but a function of complex process in the central nervous system.

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A recent analysis of spontaneous heart rate variability has shown it to be related to three major physiological factors: quasioscillatory fluctuations thought to arise in blood pressure control from variable frequency oscillations due to thermal regulation and respiration.
In the present paper we identified a multivariate autoregressive model and applied the spectral analysis method to R-R intervals and blood pressure data from resting five subjects. Blood pressure was measured at the aortic arch.
The R-R interval spectra show three peaks of about 4.4 beats, 2.5 beats and about 10 beats. The spectra of systolic blood pressure (SBP) show the peaks of about 4.5 beats, 2.6 beats and 31 beats. The spectra of diastolic blood pressure (DBP) show peaks of about 4.6 beats, 2.3 beats and 21 beats. So R-R intervals and blood pressure are interconnected.
Moreover, integrated relative power contribution of R-R intervals, SBP, and DBP are presented. We also propose new spectra concerning with the relative power contribution. We show that the fluctuations of SBP have the influence upon R-R intervals at the rate of 24% at frequency of 4.4 beats by the relative power contribution. The fluctuations of DBP have influenced the R-R intervals at the rate of 13% at the same frequency. Residual 63% of fluctuations of R-R intervals are self-fluctuations.
In this paper, the results of atropine injection into a patient are also reported.
These analytical methods are useful for the biomedical multivariable feedback control-system.

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Evoked potentials in response to flash stimulation or photic evoked potential (PEP), as recorded from occipital scalp electrodes, consist of several negative-positive peaks starting approximately 40 msec following stimulus onset. The present study is aimed at quantitatively expressing the features of the PEP.
In this paper we propose the evoked potential model which consists of a parallel combination of the second-order systems with time lags. The model parameters are obtained optimally in the frequency domain by the Fletcher-Powell method of optimization. By using the evoked potential model, the PEPs of several subjects are analysed, and the PEP waveforms can be decomposed respectively into several basic waveforms. The superposition of the basic waveforms by the model thus determined shows a good approximation of the PEP waveform, and the characteristic parameters of the PEP can be calculated by using the model parameters.

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The purpose of the EEG (electroencephalography) analysis is to extract the important information from the brain state and the brain function. In the frequency domain, power spectrum methods are often used by dividing the total frequency range into several bandwidths. In the time domain, Fujimori's analysis has been developed to characterize the EEG waves as an extension of the zero-crossing method.
In this paper, the waveform recognition method has been developed with consideration of the wave direction. The wave direction implies computation of the amplitude of the EEG wave from both the bottom and the peak of waves. The method here improves the recognition rate of the waves. Next, the EEG data have been sampled here under the 100Hz method contrary to the traditional 1kHz sampling method. After the 100Hz sampling, an interpolation function was applied. The method developed here greatly improves the EEG data reduction and shows good results of the characterization of the sleeping EEG wave.

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For the management of patient databases where the data items differ from patient to patient, the notion of conditional existence (CE) is introduced to capture the relevant items for each individual while placing every individual under the same set of items. Assuming a table consisting of patients (rows) and items (columns), a CE is expressed in the form f(X)→E(Y) and is interpreted as “a set of items Y is meaningful for those who satisfy the condition f(X)”. Based on CE's, the partition of the items is derived to form a basis for describing relevant items for any individual. Some practical applications are shown including the input procedure with the capability of identifying relevant items dynamically, and the usefulness of the methodology in patient data management practice is discussed.

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