Improving Transfer of Parkinson's Disease Patients – Sit-to-Stand Motion Assistance

In many areas of the world, population aging is steadily increasing. Japan became an aged society in 1995 and the numbers of Japanese citizens aged 65 years and above (elderly) continues to increase. In 2010, the percentage of elderly people in Japan reached 23.1%. In such a “super-aged” society, health maintenance, along with the prevention and treatment of diseases, are important long-term social care issues affecting elderly people. Because the incidence of Parkinson’s disease (PD) onset increases among persons over 50 years of age, it can be considered an age-related ailment, and there were approximately 145,000 confirmed PD patients in Japan at the time of this research. PD is caused by the death of dopamine-containing cells in substantia nigra of the brain. Common symptoms of PD are tremors, muscle stiffness, slow movement and poor balance, as well as other movement-related problems. When walking and during sit-to-stand motions, persons afflicted with such symptoms face increased risks from falls and subsequent injuries. Ensuring efficient and safe transfer motions helps ensure self-reliant lifestyles, especially among elderly and physically disabled people, including PD patients. Transfer motions are among the basic activities of daily life. To help such persons, there are a number of commercially available sit-to-stand assistance devices on the market today, most of which assist users in rising from chairs by means of a lift seat that reduces the load on their lower limbs. However, from the viewpoint of maintaining lower muscle strength, excessive assistance is undesirable. Because of this, we have developed an effective sit-to-stand assistance system that provides the minimum assistance necessary. In this paper, an outline of our developed sit-to-stand assistance system is introduced and experiments with this system involving individuals diagnosed with PD are described. It was found that the proposed system effectively permitted individuals to rise from a seated position.