It is important to record electrocardiogram (ECG) and exercise intensity simultaneously to have patients with ischemic heart disease recognize their safe lifestyle and to have patients with diabetes mellitus and hyperlipemia keep exercise therapy effectively. We have developed an ambulatory 24-hour-recording device of electrocardiogram and exercise intensity as well as the analytic system of the data. This device, put on the waist, was composed of a bimorphic accelerometer to measure intensity, a voltage-frequency converter and a wave-form regulator. The regulator formed a rectangular pulse with a constant pulse width of 0.05 msec so that exercise strength was expressed as frequency change. Outputs from this device were tape-recorded together with electrocardiogram on a 4 channel ambulatory recorder (SM-28, Fukuda Denshi Co. ltd.) and the recordings were analyzed through the use of a 24-hour ECG analyzer (SCM-280, Fukuda Denshi Co. ltd.). Timing signals generated by a clock circuit equipped in the recorder and event marker pulses were recorded on another channel. One channel is open for any information necessary. These data were treated by an analyzer (SCM-280, Fukuda Denshi Co. ltd.) and the output from it were further transmitted to a personal computer (PC-9801, NEC) through an interface (RS-232C). In the computer, exercise intensity, heart rate, ST segment displacement of ECG and recording time are processed at an interval from 10 to 60 seconds which the examiner desires. Graphic expressions about the relationships of heart rate, ST segment displacement of ECG, and exercise intensity on the time table can be displayed on a CRT. The output frequency from the accelerometer recorded while 8 subjects walked on a flat slope treadmill correlated well (r=0.95) with the presumed exercise intensity.

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Functional electrical stimulation (FES) has been proposed as a technique that could reconstruct the paralized functional mobility of the patients who injured their spinal cord and so on. A new method with which nerve conduction could be blocked electrically was studied in this report in order to suppress an undesirable excitation caused by the spinal reflex in applying FES clinically. The method for blocking nerve conduction electrically seems to be useful in applying FES to the patients widely. Some methods for it have been already proposed, neither of which, however, has been applied clinically. Slowly-rising pulse stimulation was proposed in this report as a new method for it. The proposed stimulation might be used clinically because nerve conduction was expected to be blocked locally with a relevant electrical stimulus intensity. First of all, we tried to confirm the ability to block nerve conduction in Frankenhaeuser-Huxley model simulation. Next, acute animal experiments with 3 rabbits were performed in order to evaluate the effect of the stimulation practically. It was found in simulation that nerve conduction could be blocked locally with the slowly-rising pulse stimulation which had the relevant stimulus intensity. On the other hand, it was indicated in the animal experiments that the greater the rise time of the stimulus pulse was, the higher the stimulus threshold was. The tibial nerve was stimulated by a cuff electrode while the EMG signals were recorded from the medial gastrocnemius innervated by the nerve in each of the animal experiments. From analyzing the parameters used in the simulation, these results seem to be caused by the inactivated membrane of nerve fibers. The probability that nerve conduction could be blocked with the slowly-rising pulse stimulation was confirmed with the results of the simulation and the acute animal experiments is this report.

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A telemetry system of disposable diaper for monitoring urinary incontinence has been developed. Two conductive sheets were used as electrodes and were sandwiches to an absorbent polymer of a diaper. Conductance change in diaper after urinary incontinence was monitored. The system consisted of conductive sheets as sensors, transmitter and receiver. When urinary incontinence occurred, the signal was detected by receiver and alarm LED was flashed. The alarm telemetry system included a disconnection of sensor and a battery check. In clinical evaluation, bed fasten patients and patients who used wheelchair were monitored. 32 out of 35 urinary times were observed correctly. The errors of the system developed were caused by detection of effusion of bedsore and a little watery stool because of high sensitivity. A shape of a conductive non-waven fabric electrode was modified to prevent errors and to detect urinary incontinence of a volume more than 100ml. In the second clinical evaluation with modified electrodes, the same patients were monitored. All urinary times were observed correctly. This telemetry monitoring system developed may be useful at home.

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A new diagnosis support system of chronic liver disease had been proposed. This system is composed of two steps. One is an artificial neural network step. A back propagation neural network was designed to diagnose seven classifications of chronic liver diseases: CIH, CAH, LC, HCC, FL, ALD, and Normal. The other is a medical rule base step. The output of a neural network are checked by this rule base. The network architecture had constructed each disease. Network inputs are consisted within 26 laboratory data per 187 patient cases. After being trained the system classified chronic liver diseases correctly in 141 of 187 cases. An accuracy of 75.4% is higher than the average score (63.0%) by 5 hepatologists. When sufficiently sophisticated, this system may significantly improve the analysis of chronic liver disease.

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Micro-calcifications are known to be early signs of breast cancer. Realizing that early detection is important in cancer prevention, our group developed an automatic micro-calcification detection algorithm. This algorithm can be subdivided into four processes: (1) First, using a threshold selection method based on discriminant and least squares criteria, two threshold are chosen to separate the breast region from the background. Afterwards, additional noise eliminating processes are applied to improve the extraction precision. (2) Next, Tophat processing, a mathematical morphology application, is used to smoothen non calcific regions in the breast region. Consequently, the micro calcifications are emphasized. (3) The Tophat image is then binarized to specify the region of calcification candidates, by a threshold value obtained directly using a semi-automatic (image histogram-dependent) thresholding method. (4) Finally, to improve extraction precision, further elimination of noise components in calcification candidates using a medically based area thresholding is performed. Evaluation of the algorithm was carried out on 14 samples. From these, 25 candidates (14 were calcific and 11 were normal) were obtained. Misclassification occurred in three cases; 1 calcific candidate was classified as normal and 2 normal candidates were classified as calcific.

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Functional electrical stimulation (FES) has been proposed as a technique that could restore the paralyzed motor functions of the patients who injured their upper motor neurons. In this paper, use of voluntary movement of the auricula was proposed as a control command for FES system. The movement may be used exclusively for controlling FES system, because it is seldom used in daily living. However, the percentage of persons who can move the auricula is small. In order to overcome this difficulty, a method of learning the movement was developed in this paper. The method was a training with electrical stimulation to the posterior auricular muscle and electromyogram (EMG) feedback. Three subjects attempted to learn the movement with this method, and two of them acquired the movement in a short term. Furthermore, in order to detect the auricular movement by EMG signal of the posterior auricular muscle, we studied the influence of other movements on the detection of the auricular movement. Power spectrum of noise during neck movement was distributed in lower frequency than that of the EMG signal. The noise during jaw movement was smaller in amplitude than the EMG signal. These experimental results suggested that the influence of both neck and jaw movements on detection of the auricular movement could be removed by appropriate signal processing. In addition, we also studied about fatigue characteristic of the posterior auricular muscle and reaction time of the auricular movement. It was difficult to move the auricula constantly over 1 minute, but it was probable to move it intermittently for 15 minutes. The reaction time of the movement was a little longer than that of finger movement. These suggested that the auricular movement could give short-time control commands repeatedly to FES system for long term.

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Tremor, which is the invisible mechanical vibration observed at body parts, is classified into physiological and pathological tremors. Physiologial tremor is observed at body parts of normal subjects. It was reported that an oral dose of alcohol could decrease the amplitude of pathological tremor. Therefore, there might be much possibility of the physiological tremor replacing alcohol concentration in expiration as an non-invasive and easy measurement method to estimate the influence of drinking. We attempted to clarify the influence of drinking on the physiological tremor. In this paper, power spectrum of the physiological tremor of the index finger were measured at every 15 minutes for 3 hours under drinking and normal (non-drinking) conditions. Subjects were 10 males aged 20 to 25 years. Under drinking condition, we instructed subjects to drink 43% proof whiskey mixed with water. The amount of an oral dose of the whiskey was 1ml per 1kg of subject's weight. It was found that total power values of the physiological tremor from 15 to 135 minutes after drinking were relatively smaller than that before drinking under drinking condition. From the results of t-test, it was clear that the influence of drinking could be estimated by the total power of the physiological tremor.

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A new bed monitoring system of the poses of a patient by using an electrostatic method has been developed. A two-dimensional array (8×8) of condensers is composed of electrodes attached to both sides of a mat, and the capacity of each condenser varies depending on the local sinking of the mat with the weight of a patient. The capacity of each point is transformed at first to an electric signal through the circuit using FET, and then to a time serial signal with X, Y scanning. The signal is processed by spline supplementing program to make the contour map displayed on CRT. The displayed map could show the various lying poses or any movement of a patient on the bed.

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