Yutaka Tomita

The purpose of this study was to evaluate the short term effects of continuous passive range-of-motion exercise (CPROM-E) on passive resistive torque of the hip and knee. The subjects were 4 healthy adults and 6 spastic patients. During the CPROM-E, the joint angle and the load torque of the hip and knee were measured, and surface electromyogram of the vastus medialis and medial hamstrings was recorded. Peak torque of the joints or peak amplitude of the integrated electromyogram (I-EMG) was plotted against time of exercise, and the slope of the plots were analyzed by the t-test. In the healthy subjects, the peak torque of the hip decreased steadily and significantly (p<0.0001) by about 5 percent after CPROM-E, although the peak amplitude of I-EMG was not always reduced. In the spastic patients, the peak torque of the hip decreased significantly (p=0.01), by about 35 percent, and the peak amplitudes of I-EMG also decreased significantly (p=0.0003 and p=0.01, respectively). In one patient, the peak torque of the knee was analyzed and was found to decrease significantly (p<0.0001). However, there was no consistent change in the H-wave amplitude of the medial head of the gastrocnemius. Both reflex and non-reflex components of the joint resistance may play a role in reduction of the joint torque during CPROM-E.

There have been many devices for paraplegic standing and walking, but they are not used in daily living because of their inconvenience. The Walkabout^[○!R] is a new HKAFO system with a medial single hip joint (MSH-KAFO) invented by McKay S in 1992. Compared with other HKAFO systems, the hip joint of MSH-KAFO is compact and removable, so it has a distinguish merit in the point of reality, that is, ease of donning-doffing the device, compatibility with W/C, cosmesis, and cost. We had clinical experiences with using MSH-KAFO for five paraplegic patients due to spinal cord injury. They were all males, aged 26 to 36 years old. Their functional levels were L1 (2 cases), T1O (2 cases) and T5 (1 case). Results : 1) All patients could stand stably without crutches and walk in P/B immediately at the first time of wearing braces. 2) After a few hours of crutch walk exercises, all of them could walk independently with Lofstrand crutches. 3) Their walking speeds were ranged from 10.0 to 37.5 m/min (mean 19.94 m/min) at the follow-up points (mean 7.1 months). 4) With 4 cases, we measured oxygen consumption. At comfortable walking, predicted energy costs were from 1.31 to 3.89 METs (mean 2.75 METs). Compared with the data in literature, it seemed to be the same level with normal walking, and lower than the KAFOs walking. Our results suggest that MSH-KAFO is a very convenient standing and walking device for paraplegics, which is compatible with W/C using.

To record the displacement of the trunk during gait easily, we placed a portable accelerometer on the subject's back. We examined the reproducibility of the testing and compared it with the measurement of the ground reaction forces with the force plates and our simple motion analysis system using three laser pointers and a video camera. Subjects were five healthy adults and one paraplegic patient. The paraplegic patient whose functional level was T10-11 can walk independently with Lofstrand crutches and a hip-knee-ankle-foot orthosis system with a medial single hip joint (Walkabout^[○!R]). The subjects who were equipped with the accelerometer at the back of the trunk were directed to walk twice on the force plates at a comfortable speed. The test-retest cross-correlation coefficients ranged from 0.46 to 0.94. The cross-correlation coefficients between the accelerograms from the accelerometer placed on the back and the ground reaction forces ranged from 0.73 to 0.93. With the paraplegic patient, we measured the displacement of the trunk during walking with our motion analysis system. When we added the functional electrical stimulation (FES) to the Walkabout^[○!R] system, he could walk faster and the displacement of the trunk in the horizontal plane significantly decreased. The peak-to-peak amplitudes of the accelerographs in the horizontal plane did not differ with or without FES. These results suggest that the gait analysis using a portable accelerometer placed on the back and our motion analysis were valid for clinical use.

Magnetic flowmeters, which have been one of the standard instrument to measure liquid flowrate in industry, were applied to tomographic imaging of flow velocity field, based on the fact that there are no exciting magnetic fields that induce the flow signal proportional to volumetric flowrate free from the velocity profile. Two-dimensional case was examined theoretically for the reason of simplicity, and a flowmeter with eight magnetic coils and eight signal pick-up electrodes was developed. Driving alternating current of unit ampere was fed to eight combinations of pairs of the coils and induced electro-motive force were picked up across eight combinations of pairs of the electrodes. Flows in a pipe were assumed to be fully developed and axially symmetric since the straight approach flow has the length of forty-five times of the pipe diameter (45D). Since field interaction model of the meter is ill-posed, some prior knowledge, such as non-negativeness of the flow velocity and smoothness of the profile, was introduced to reconstruct the velocity profile.<br>In order to examine the possibility of reconstructions for various velocity profiles, to make different velocity profiles is needed. When the pipe is shifted perpendicularly to its axis, the weight function is different from what it was. Therefore the shift of the pipe position was treated instead of the different velocity profiles for simplicity. As a result, when the pipe was shifted, the same reconstruction regardless to displacement was achieved. The flowrate estimated with the present equipment agreed with a commercially available standard magnetic flowmeter within 5% accuracy.

Magnetic flowmeters, which have been one of the standard instrument to measure liquid flowrate in industry, were applied to tomographic imaging of flow velocity field, based on the fact that there are no exciting magnetic fields that induce the flow signal proportional to volumetric flowrate free from the velocity profile. Two-dimensional case was examined theoretically for the reason of simplicity, and a flowmeter with eight magnetic coils and eight signal pick-up electrodes was developed. Driving alternating current of unit ampere was fed to eight combinations of pairs of the coils and induced electro-motive force were picked up across eight combinations of pairs of the electrodes. Flows in a pipe were assumed to be fully developed and axially symmetric since the straight approach flow has the length of forty-five times of the pipe diameter (45D). Since field interaction model of the meter is ill-posed, some prior knowledge, such as non-negativeness of the flow velocity and smoothness of the profile, was introduced to reconstruct the velocity profile.<br>In order to examine the possibility of reconstructions for various velocity profiles, to make different velocity profiles is needed. When the pipe is shifted perpendicularly to its axis, the weight function is different from what it was. Therefore the shift of the pipe position was treated instead of the different velocity profiles for simplicity. As a result, when the pipe was shifted, the same reconstruction regardless to displacement was achieved. The flowrate estimated with the present equipment agreed with a commercially available standard magnetic flowmeter within 5% accuracy.

Objective evaluation of the patient's condition is important in a clinical diagnosis. Since the frequency characteristics of the respiratory impedance represent the airway constriction, they are often used to diagnose the obstructive lung diseases. Forced oscillation technique is appropriate to measure the respiratory impedance, and has been often used. But due to the limit of the frequency response of conventional device, the frequency characteristics of human respiratory impedance could be measured only up to 20Hz. In this study, by differentiating displacement signal of the piston which excites the flow, the frequency characteristics of human respiratory impedance could be measured over the frequency range of 2-120Hz, and found to be characterized by two resonances at 8-10Hz and at 80-100Hz. Conventionally, to obtain the frequency characteristics, FFT technique was frequently used, and it required long measurement time. But since it is difficult to confine patients with advanced obstructive lung diseases to a measurement instrument for a long time, we tried to shorten the measurement time by employing the Auto-Regressive Moving Average model (ARMA model) parameter estimation technique, which made it possible to measure the frequency characteristics with a data of one second, corresponding to about one sixteenth of the conventional FFT method. In addition, by using the estimated ARMA model parameters, a 4-element equivalent electrical circuit model is derived for the human respiratory system. Four element values were measured for ten normal males, and found to be slightly lower than those of the previous reports, which had noticed only the resonance at 8-10Hz. Since the 4-element model represents the condition of the human respiratory system, the estimated values can be applied to the clinical diagnosis of lung diseases. The respiratory function test was carried out to determine the degree of constriction of human airway passages induced by cigarette smoke particle irritant aerosols. Nine normal male smokers were asked to inhale cigarette smoke deeply 15 times over 5 minutes (nicotin 1.35mg, and tar 21mg). After smoking, increases in resistance, which indicated the acute effect of airway passage constriction, were observed.