Evaluation of human activities and sleep-wake identification using wrist actigraphy.

The purpose of this study is to investigate the count-characteristics of wrist actigraphy in basic human activities and to discuss the agreement of sleep-wake identification between polysomnography (PSG) and wrist actigraphy during nocturnal sleep. There was a distinct distribution of actigraphy counts over the studied activities. The evaluation of sleep-wake scoring using the wrist actigraphy agreed 96.9% with the polysomnographic scoring during nocturnal sleep.

Effects of centrally acting drugs on the frontal midline theta activity in man.

The frontal midline theta activity which appears during a performance of mental tasks has been designated as Fm theta. Sixteen male university students who showed the appearance of Fm theta in 3 consecutive days were given 4 centrally acting drugs, i.e., diazepam 5 mg, amobarbital 80 mg, methylphenidate 15 mg and placebo, in a double-blind, crossover design. Scores were made on the state anxiety scale of Spielberger's State Trait Anxiety Inventory (STAI), and EEGs were recorded monopolarly before and during the performance of an arithmetic addition. The test was done twice, before and one hour after the drug administration. Placebo increased the appearance time of Fm theta, decreased the STAI scores and increased the tasks. Diazepam increased the appearance of Fm theta and decreased the state of anxiety but did not influence the amount of tasks. Amobarbital changed neither the appearance of Fm theta nor STAI scores but decreased the tasks slightly. Methylphenidate failed to influence the appearance of Fm theta but increased both the STAI scores and performed tasks. These results suggest that the appearance of Fm theta is influenced by the drugs and that the relief from anxiety might be involved in the appearance of Fm theta.

A useful tool for predicting the clinical effects of hypnotics in humans: averaged photopalpebral reflex.

The averaged photopalpebral reflex (PPR) is an index which objectively assesses the arousal level of humans. The dose-response curve of flunitrazepam, a benzodiazepine derivative, was investigated by using PPR in the present study. Ten healthy male university students were given flunitrazepam 0.5 mg, 1.0 mg, 1.5 mg, 2.0 mg and placebo in a double-blind, crossover design. PPR and subjective assessment were recorded before and after drug administration. P1 and P2 latencies of PPR were prolonged by flunitrazepam 0.5 mg, 1.0 mg and 1.5 mg in a dose-dependent manner. The prolongation of latencies by flunitrazepam 2.0 mg was weaker than that by 1.5 mg, but was more potent than that by 1.0 mg. In self-assessments, sleepiness, muscle weakness and vagueness of thought were observed after drug ingestion. Sleepiness was correlated with the prolongation of the PPR latencies. These results suggest that PPR could be a useful tool for psychopharmacological investigations in normal humans, that flunitrazepam might be a clinically potent hypnotic drug, and that its peak effect occurs 2-3 h after administration.

[Measurement study of anatomical shape and size in Japanese elbow joints].

Recently, total elbow replacement has been developed for reconstruction of destructed elbow joints. However, various complications occurred in the constrained or semi-constrained types of elbow replacement, while unconstrained type such as surface replacement showed lower incidence of such complications. On the other hand, development of the elbow prosthesis needs anatomical measurement of the elbow for adaptation to the need of Japanese. Basically, prosthesis should be designed based on the anatomical and biomechanical analysis. In this study, elbow from 36 Japanese cadavers were measured in the outer contour and microradiograms of the sectioned samples. Midline axes of the humerus and ulna, and the center of both medial and lateral epicondyles are fixed as standardized lines for the study in the elbow measurement. The trochlea is situated slightly anteriorly from the midline of the humerus. Width of the trochlea is 21.4 +/- 2.6 mm on the right side and 21.1 +/- 2.8 mm on the left at the anterior margin. At the distal margin, the width is 23.5 +/- 2.8 mm on the right and 23.3 +/- 2.6 mm on the left, and at the posterior margin, 23.9 +/- 3.6 mm on the right and 23.5 +/- 2.8 mm on the left. Saggittal section of the humeral end shows almost complete circle in the articular surface of the trochlea. The diameter is 19.1 mm on the right and 19.3 mm on the left at the longitudinal axis of the humerus, 17.6 mm on the right and 17.7 mm on the left at the central groove, and 24.5 mm on the right, 22.6 mm on the left at the medial margin. Anterior angulation of the trochlea is about 12 degrees. Central line of the trochlea corresponds to the center of the flexion-extension of the elbow, but angulated by 8 degrees from the humeral axis from the anterior view, and internally rotated by 3 degrees from the center of the both epicondyles from the bottom view. In the measurement of the incisura trochlea, opening distance is 18.5 +/- 2.1 mm on the right, 18.5 +/- 2.0 mm on the left, and the depth is 11.8 mm on the right, 11.6 mm on the left at the mean. Forward angulation of the incisura is 30.8 degrees on the right and 28.3 degrees on the left. Width of the olecranon is 25.0 +/- 3.2 mm on the right, 25.0 +/- 2.9 mm on the left and the thickness is 18.6 +/- 1.6 mm on the right, 18.7 +/- 1.8 mm on the left. The central line of the olecranon is supero-laterally angulated about 7 degrees from the longitudinal axis of the ulna. This angulation and lateral opening of the central line of the trochlea seems to produce carring angle of the elbow. Measurement of the elbow size and shape is discussed for designing elbow prosthesis and some biomechanical problems are also represented.

Direct recording and reconstruction of 3-D x-ray images: some experiments.

Detailed experimental investigations of the method for recording and reconstructing 3-D x-ray images are described. A clear 3-D x-ray image of a human skull is recorded on a film 300 mm x 250 mm. The limitations of this method and a proposed modification are also discussed.

Direct recording and reconstruction of 3-D x-ray images.

Theoretical and experimental investigations of a method for direct recording and reconstruction of 3-D x-ray images are described. When recording, an x-ray source is placed at discrete positions, and an x-ray grid is fixed on the x-ray plate. When reconstructing, a lenticular sheet matched with the grid is overlayed on the developed plate, and a parallax-panoramagram type 3-D image is seen with the naked eye. Using a small x-ray source designed for use in dental clinics and an x-ray grid matched with the lenticular sheet, 3-D x-ray images having a 0.001-rad resolvable angle and a 0.02-rad flipping angle are directly recognized with clear parallax.

Real-time transmission of 3-D images formed by parallax panoramagrams.

Theoretical and experimental investigations on the real-time transmission of 3-D images formed by parallax panoramagrams are described. At the image-taking station, a 3-D image is optically decomposed into line images, which can be directly handled by a high resolution TV set. By registering a lenticular sheet to the reproduced line images on a monitor screen, the reconstructed 3-D image is seen by the naked eye. By using an ordinary color TV set with a 350-line resolution and a cylindrical lens array with a 3-mm pitch, 3-D color images composed of thirty-five elements in the horizontal direction and seen from four directions are successfully transmitted and reconstructed with clear parallax.

Real-time transmission of a 3-D image using volume scanning and spatial modulation.

Theoretical and experimental investigations on real time transmission of a 3-D image using volume scanning and spatial modulation are described. By using a phase stabilized spatial modulation, a 3-D image is transmitted in real time at the rate of fifteen 3-D images per second. The signal and noise, the effect of continuous illumination, and the conditions for distortion-free imaging are shown with experimental verifications. The present system can be realized with presently available optical and electronic components.

Signal-to-noise ratios for hologram images of subjects in strong incoherent light.

When normal laser holographic technique is applied to subjects in strong incoherent illumination, an additional darkening of the photographic plate due to the incoherent light is introduced. Effects of the darkening on the signal-to-noise ratio of the reconstructed image are analyzed using a simplified model for photographic plate characteristics. Optimum values of the fraction of laser light used as reference, plate exposure, and S/N are obtained. Reconstructed images of reasonable contrast and pictorial quality have been obtained for 3-D subjects illuminated with substantial incoherent light intensity in addition to the laser light.