One of the strictest responsibilities for biofeedback apparatus constructor is "the products liability". Products liability refers to the liability of any or all parties along the chain of manufacture of any product for damage caused by that product. This includes the manufacturer of component parts (at the top of the chain), an assembling manufacturer, the wholesaler, and the retail store owner (at the bottom of the chain). Products containing inherent defects that cause harm to a consumer of the product, or someone to whom the product was loaned, given, etc., are the subjects of products liability suits. Products liability claims can be based on negligence, strict liability, or breach of warranty of fitness depending on the jurisdiction within which the claim is based. In any jurisdiction one must prove that the product is defective. There are three types of product defects that incur liability in manufacturers and suppliers: design defects, manufacturing defects, and defects in marketing. Design defects are inherent; they exist before the product is manufactured. While the item might serve its purpose well, it can be unreasonably dangerous to use due to a design flaw. On the other hand, manufacturing defects occur during the construction or production of the item. Only a few out of many products of the same type are flawed in this case. Defects in marketing deal with improper instructions and failures to warn consumers of latent dangers in the product. Products Liability is generally considered a strict liability offense. Strict liability wrongs do not depend on the degree of carefulness by the defendant. Translated to products liability terms, a defendant is liable when it is shown that the product is defective. It is irrelevant whether the manufacturer or supplier exercised great care; if there is a defect in the product that causes harm, he or she will be liable for it. In order to facilitate the consumers' legal burden, empirical law and virtually presumption of damage are applied for the product liability suits. On the other hand protest for developmental risk and prescription of accusation are provided for the benefits of the defendants.
Muscle pain is the primary cause of discomfort for more than 30% of patients who visit their primary physicians with severe pain. These pains are often caused by dysponesis which is unaware misdirected muscle efforts not necessary for task performances. It can consist of 1) excessively tightening muscles that are used for the task performance, 2) tightening muscles not necessary for the task performance (inappropriate co-contractions), 3) not relaxing muscles after the task has been completed, or 4) not relaxing muscles momentarily during task performance to allow for ongoing regeneration (surface electromyograhic gaps/micro-breaks). These chronic covert muscle tensions are a significant co-factor in the etiology, maintenance and progression of many disorders such as headaches, backaches, joint pain, repetitive strain injuries, myalgias, etc. Dysponesis can be identified with surface electromyographic (SEMG) feedback. The benefits of using SEMG to reduce dysponesis through awareness and training are illustrated by two clinical case examples: 1) to improve health at work when packing apples and 2) to enhance performance while working out in the gym on an elliptical exercise machine. As documented by the SEMG recorded from the upper trapezius and/or forearm flexors, the reduction of misdirected muscle efforts decreased the neck and shoulder pains at work and at home and enhanced performance on an elliptical exercise machine. SEMG is a useful clinical tool to assess, monitor, provide feedback to the therapist and client, document muscle dysponesis, and teach clients awareness and voluntary control to reduce their dysponesis and improve health.
The purpose of this study was to examine the psychophysiological response during learning movement patterns of "the string figures" and "the origami". 10 healthy females were played two tasks; one was the string figure task and the other was the origami task. They exercised the each task to learn the movement pattern by heart (exercising), and after that they repeated them for three minutes (after exercising). Electroencephalogram (EEG), the mood scale for measuring psychological arousal level and hedonic tone, the self-assessment (skillfulness, concentration, and enjoyment) were measured about each performance. The results were as follows. In frontal area, beta activities were increased after exercising in comparison with exercising in both tasks. In central and parietal area, beta activities were increased after exercising in comparison with exercising in the origami task. In self-assessment, the point of "concentration" in the string figure task was higher score than that the origami task, and point of skillfulness and enjoyment after exercising was higher than exercising in both tasks. These results suggested the origami has higher load of the exercise than the string figures, but the string figures needed higher concentration than the origami in exercising and after exercising of movement patterns in fast learning stage, that was one of the characteristics of performing the string figures.
We investigated the process of modulating speed by comparing two subject groups who chose different speeds. Sixteen female subjects were asked to perform a continuous forearm rotation movement task at their individually chosen speed, after which they were divided equally into two groups based on their chosen rotation speed (Fast-Preferred Pace group, FPP; Slow-Preferred Pace group, SPP). Eight pairs were then randomly chosen from the groups and matching speed was investigated. We found that the matching speed was faster than the initiated speed in the SPP group and slower than that initiated in the FPP group. During the matching period, rotation speed tended to increase and the coefficients of variations for rotation speed were similar. Thus, we concluded that determination of movement speed and the coefficients of variations for that speed may be a sensitive means to measure synchronization. After the matching period, the rotation speed of the SPP subjects was faster than their original initiated speed. These results suggest that fast movement speed may have a greater influence than slow movement speed.
The object of this study was to develop a method for "Efficient rest", in other words enabling sufficient rest in a limited amount of time, using biosignals compatible with the body. The characteristics of heart rate and respiratory variation were investigated in the following three states: seated rest, bicycle ergometer exercise, and light sleep. The result showed differences between states in the period and fluctuation of heart rate and respiratory variation, as well as respiratory waveform. We next applied contact vibration pressure stimuli based on the obtained respiratory waveforms using a massage chair, and investigated physiological and psychological changes. The stimulus frequency was varied so that it was highest at the point of transition from inspiration to expiration and lowest at the point of transition from expiration to inspiration. A total of five types of stimuli were used, specifically three types based on actual respiratory waveforms (rest, exercise, sleep) and a stimulus in which the period of exercise stimulus was multiplied by 0.8 (enhanced exercise) and another in which the period of sleep stimulus was multiplied by 1.2 (enhanced sleep). The result showed differences among stimuli in the tendency of changes in physiological and psychological conditions.
In this study, focusing on "Body Image", which takes a part of controlling the precise motions of limbs, we developed the training device to improve the functions of Body Image of hemiplegic upper elbow. The training device contain the displaying function of computer graphics (CG) to present the model motion of flex of elbow and to feedback the error of elbow's angle between the angle of model and the user's angle of elbow simultaneously. As the result, it is clarified that the visual feedback function to display the dynamic behavior of error between the model image of CG and the user's real elbow cause the temporal development of the user's adaptive behavior to the device. The result suggests that biofeedback function realize the function for the rehabilitation of Body Image, and the function generate the mechanism to trigger the chain reaction to let the improvement of the Body Image improve itself. Also the training device containing the additional interactive function to control the model motion according to the user's motion realize the more efficient training with the enhancement of the mechanism of chain reaction.