Passive and active-assistive motions are empirically known to be effective for the functional restoration of the paretic muscles. Ongoing passive elbow flexion decreased electromyographic reaction times of the biceps brachii for the elbow flexion. The present study examined how the early EMG activities of the biceps brachii for elbow flexion were affected by ongoing passive elbow motions.
In the following three experiments, the subject was asked to respond to a tone stimulus by flexing his left elbow as, quickly as possible, and rectified surface EMG activities of the biceps brachii were added 5 or 10 times during first 128msec.
(1) The effect of passive motions of the ipsilateral (left) elbow with angular velocities of 20deg/sec was studied in seven subjects. The EMG activities during the passive motions, of whichever directions, reduced significantly for first 60 or 70msec, compared to the condition without passive motions.
(2) The effect of passive motions of the contralateral (right) elbow with angular velocities of 20deg/sec was studied in three subjects. The passive motions did not influence the EMG activities.
(3) The effect of passive motions with different angular velocities ranged from 5 to 20deg/sec was studied in four subjects. Compared to passive motions of the same direction to the response-motion, the EMG activities increased during passive motions of the opposite direction. This phenomenon became remarkable at faster angular velocities of passive motions and after 40msec from the onset of the EMG activities.
It is assumed that the decrease of early EMG activities caused by ongoing passive motions is related to the modification of motor program by kinesthetic input. The difference of the EMG activities between the two directions of passive motions, the same and the opposite, would be attributed to the spinal reflex mechanism. Although passive and active-assistive motions facilitate the initiation of motor activities of the prime-mover muscle, they are not effective to increase the muscular strength.

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Sensory nerve conduction studies of the radial, median and ulnar nerves were carried out in healthy normal subjects by conventional techniques using surface electrodes.
Sensory nerve conduction velosity (SCV) and the amplitude of sensory nerve action potential (SNAP) were measured by both the orthodromic and antidromic techniques. Electrodes were placed on the elbow, the wrist and thumb, index and little fingers, respectively. SCV was calculated by the latency time which was taken as the time from stimulus artifact to the first deflection. The amplitude from negative peak to positive peak was considered the amplitude of SNAP.
The mean SCV did not show the significant difference between two techniques in the three nerves. On the other hand, the amplitude of SNAP in antidromic measurement was 2 or 3 times higher than that in orthodromic one. But, in the antidromic study of ulnar nerve, M wave overlapped SNAP as the stimulation voltage increased. Consequently, in order to get high amplitude of SNAP, the antidromic technique was preferable, but one had to examine the ulnar nerve carefully because M wave often overlapped.
One could also pick up the SNAP from the other nerve at the wrist or elbow, when the digital nerve was stimulated. This phenomenon could be caused by the anatomical abnormality, spread of the SNAP or the overflow of the stimulus current. Therefore, one must carefully perform the sensory nerve conduction study, since this phenomenon was noted between the radial and median nerves and between the median and the ulnar nerves as well.

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Using reaction time experiment (RT), differences of efficiency in simultaneous motions between the left and right side were examined on 10 normal subjects, 10 patients with left hemispheric lesion (LHL) due to cerebrovascular disease, and 10 with right hemispheric lesion (RHL). The subject, responding to sound stimulus presented about 2 sec after a verbal warning, extended his wrist as fast as possible in following conditions: the left or right wrist-extension alone (single condition), and extension of the left or right wrist with dorsiflexion of the ipsilateral ankle (simultaneous condition). EMG activities of finger extensor muscles were picked up with surface electrodes and recorded on a memoscope, where the time elapsed from the stimulus onset to the initial activities (RT) were measured with msec scale. Mean RTs were calculated from 15 trials. Compared to the single condition, RTs of the simultaneous condition were long. RT differences between the two conditions (Δ) were obtained by subtracting RT of the single condition from RT of the simultaneous condition. The right Δ was larger than the left in the normal group, whereas the left Δ was larger than the right in the LHL group. In the RHL group there was no significant difference of Δ between the left and right side. It is assumed that performance of simultaneous motions is more efficient on the left side than on the right in the normal subjects, which would reflect the functional difference between the left and right hemisphere, i. e., serial and parallel processing of information, and asymmetry of channel capacities. However, the result obtained from the patients with LHL and RHL could not be explained by the deficit of such differentiated function, but it should be attributed to functional reorganization after hemispheric lesion.

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Generally a balanced forearm orthosis (BFO) is used to assist the dystrophic patients with proximal muscle weakness in performing upper extremity activities. It is adjustable so that the arm will run downhill with gravity and will be moved uphill by the muscles.
An adjustable not severely weakened and well co-ordinated muscle as power source must be available to drive the ordinary BFO uphill and downhill. However, the patients with severe proximal weakness or paralysis are often unable to drive or control this orthosis.
We have recently developed an externally powered balanced forearm orthosis for them.
The results of clinical use in two limb-girdle dystrophic patients with severely proximal weakness showed that this device was an effective and useful one.

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[in Japanese]

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