- Difference in response times on hand mental rotation task between the back
and palm of the hand in elderly individuals
- 論文掲載日：2017/12/28 第17巻
- Purpose: The hand mental rotation task (HMRT), in which participants judge whether a picture of a hand is of the left or right hand, is thought to induce a participant’s motor imagery. This application of this task in rehabilitation has begun. However, the task performance strategy used on presentation with a picture of the back of the hand and the palm in elderly individuals has not been sufficiently elucidated. In this study, we examined the performance strategy of the HMRT in response to pictures of the back of the hand and the palm among elderly individuals.
Participants and methods: A total of 75 right-handed individuals aged 65 years or older (38 men and 37 women, 74.9 ± 5.8 years old) were included in this study. From the position in which the middle finger was located at 0 degrees vertically, the pictures of the left/right hand and the back of the hand/the palm were turned in increments of 60 degrees in presentation, and the response time (RT) and correctness of responses were recorded. The RT to the left and right arrows was also measured, and the ΔRT was derived by subtracting the RT to the arrows from the RT to the hand pictures. A repeated measures ANOVA was conducted on the ΔRT with three factors: whether the hand was left or right, whether the back of the hand or the palm of the hand was pictured, and the presented angle.
Conclusions: We suggest that the motor imagery strategy was combined with the visual imagery strategy when pictures of the back of the hand were presented and that the motor imagery strategy was used when pictures of the palm were presented. These results indicate that frequent use of pictures of the palm may be effective when the HMRT is used for rehabilitation of elderly individuals.
Keywords: Motor imagery, Visual imagery, Aging, Rehabilitation, Motor response generation
- Pain related to breastfeeding in seated and side-lying positions: assessment and recommendations for improved guidance
- 論文掲載日：2017/10/24 第17巻
- Purpose: To explore the relationship between breastfeeding positions and pain in the upper arms and shoulders.
Subjects and Methods: Twelve subjects with breastfeeding experience participated in an experiment and survey. In the experiment, subjects embraced two dummy infants with different weights, in six different positions, such as the cradle hold and side-lying hold, while electromyography (EMG) and video were recorded at six sites: the right and left forearms, upper arms, and shoulders. The survey asked for responses to 37 items such as sites where pain was felt during breastfeeding, type of hold during breastfeeding, and guidance received from medical institutions or other advisors.
Results: The 11 subjects who provided valid data were analysed. In training and practice with breastfeeding positions at medical institutions, only two subjects had received guidance on the side-lying hold, but 10 had used it. In terms of the positions of the upper arms in each hold, seven patterns were observed for the side-lying hold. Spearman’s rank correlation coefficient for left/right location of chronic pain and frequency of breastfeeding with the left/right breast was 0.95 (p<0.01). Eight of 10 subjects who had performed the side-lying hold felt short-term pain in the upper arm and shoulder of the breastfeeding side (the bottom side in the lateral decubitus position).
Conclusion: Of six breastfeeding positions, the one most frequently linked to pain was the side-lying hold. It also became clear that uneven breastfeeding with the right and left breasts in the side-lying hold, or the use of a self-taught side-lying hold position, produced short-term pain that was linked to lactation-stage pain. This shows that guidance on the proper use of the side-lying hold is needed. There is also a need for further investigation that distinguishes between different side-lying hold positions, to support teaching of appropriate body positions. Research on breastfeeding positions has the potential to reduce the burden of child-rearing on mothers and contribute to a healthier child-rearing environment.
Keywords: Breastfeeding positioning, EMG, Pains of upper arms and shoulder, Side-lying, After birth and parenting support
- Validity and reliability of Leap Motion Controller for assessing grasping and releasing finger movements
- 論文掲載日：2017/10/04 第17巻
- Objective: The leap motion controller (LMC) is a motion sensor that has recently become available and has advantages in terms of cost, size, and accuracy. However, it has not been fully investigated whether the LMC has sufficient accuracy for clinical assessments, particularly finger flexion and extension, which are important for diagnosis and prognosis in stroke or cerebral palsy patients. Herein, we have tested the validity and reliability of the LMC for measuring the grasp and release of finger movements.
Materials and methods: A healthy participant repeated finger flexion and extension movements, and his fingertip position was measured using an LMC from the palmar, ulnar, and dorsal sides of the hand. The fingertip position was also measured using an electromagnetic motion tracker and a video. The finger movement detected by the LMC was compared with those detected by the other instruments.
Conclusions: The LMC had a higher reliability in detecting the fingertip position by sensing it from the palmar or dorsal side of the hand, compared with the ulnar side. In the palmar/dorsal side measurements, an underestimation in the amplitude of the finger movement was shown in the middle range of its excursion compared to video-detected movement. However, the underestimation resulted in a highly correlated, proportional bias, especially in the palmar-side measurement, and could be calibrated by a nonlinear regression analysis. The palmar side measurement was thus the most suitable for evaluating the finger flexion and extension. We concluded that by taking into consideration the range of excursion and appropriate calibration, the validity and reliability of the LMC is sufficient for the quantitative evaluation of finger flexion and extension in laboratory experiments and also in clinical settings.
Keywords: Motion capture; Spasticity; Grasping; Bland–Altman plot
- Ergonomic evaluation of mobile work type office environments
- 論文掲載日：2017/09/23 第17巻
- Purpose: In recent years, there have been changes in awareness and institutional systems relating to work due to factors such as innovation in IT technology and adoption of work-life balance. In particular, some companies have introduced a new mobile work-style where employees are able to work anytime, anywhere. The aims of this research were to ascertain the current situation based on an ergonomic survey of workers who work in the mobile work-style, and to identify problems, and propose solutions.
Experiment participants and method: Our aim was to ascertain the current situation in offices by measuring satisfaction in terms of factors such as the comfort, fatigue, and ease-of-use of equipment and office furniture for people working in all workplace environments, not just conventional fixed offices. To achieve this, we prepared and administered questionnaires to 115 employees at two private companies which are especially committed to using the mobile work-style.
Results: Chairs and desks are found to influence the satisfaction by Structural Equation Modeling. The present survey found that the effects due to lighting/furniture and the satisfaction of network environment remarkably influenced the workers' satisfaction.
Conclusion: The current status of workers working in the mobile work-style was ascertained using a survey questionnaire. As a result, two points became clear. First, the physical environment in a company has a major impact on satisfaction. Second, is the inadequate understanding and low level of concern for ergonomics among workers. As a solution for the first, the possibilities are: (1) Improvement of worker satisfaction through proper layout/design and furniture/fixtures, (2) Improvement of work efficiency, such as the ability to concentrate and ease of viewing monitor screens through proper lighting, and improvement in peace-of-mind such as a sense of ease or pleasantness, and (3) improvement of satisfaction by developing the network environment and improving factors such as stress due to no assigned seats. A reduction in stress in office environments can be expected by adopting, as a measure to resolve the above two issues, company-wide education in the need for and awareness of using adjustment methods for chairs and other furniture, and equipment which is suited to the body.
Keywords: Mobile work-style, Office, Satisfaction
- Basic study on improving sound localisation accuracy for musical tones by adding broadband noise
- 論文掲載日：2017/03/02 第17巻
- Purpose: When presenting a virtual auditory display (VAD) to a user who has difficulty using visual information, such as a visually impaired individual, an acoustic head related transfer function (HRTF) is necessary for vertical localisation. However, measurement of the HRTF is time consuming and costly. Because HRTFs differ between individuals, the use of another person’s HRTF reduces the accuracy of localisation. In this study, we propose and evaluate an extremely simple method for improving the accuracy of virtual sound localisation on the vertical plane using the same HRTF for various individuals, which may help with the use of a VAD.
Subjects and method: Six male university students (mean age of 22.5±2.5 years) with normal hearing and sight participated in the experiment, during which they wore blindfolds. Sound localisation accuracy was compared among three different conditions: presentation of a tone alone (tone condition), presentation of broadband noise alone (noise condition), and mixed presentation of a tone and broadband noise (mixed condition). Two types of playback system were used: a speaker array and virtual conditions (hearing binaurally through headphones). The stimuli were presented from a total of 13 different directions on the median plane at 10° intervals, from -60° (lower side) to 60° (upper side).
Results: As sound sources were presented farther from 0° in either direction, the target direction offset from 0° was more underestimated. It was found that in the virtual condition, the superimposition of musical tones and broadband noise significantly improved localisation accuracy compared with presenting each alone.
Conclusion: The present study demonstrated that when presenting virtual sound without personalising the HRTF, the extremely simple method of adding broadband noise markedly improves sound localisation accuracy on the vertical plane directly ahead of a subject.
Keywords: Virtual Auditory Display, Visual Impairment, Sound Localisation, 3D Sound, Binaural, Augmented Reality.