Analysis of Involuntary Movements for Adapting Input Devices to People with Motor Impairments Based on 3-Axis Accelerometers

People with motor impairments often need adaptation of input devices to interact with surrounding people and home-appliances via communication aids and environmental control systems. During the adaptation, a body part to be used, a device to be activated, its specific location, and a posture to use it should be decided by assessing accuracy and speed of motions. Additionally, the strength and frequency of involuntary movements should be taken into account. The successful adaptation is a key determinant to improve Quality of Life (QOL). However, the adaptation is carried out, in most cases, based on only subjective assessments. That is why, we are developing a quantitative method to detect involuntary movements and measure the adaptability of input devices. Our method is based on the root mean square (RMS) values of 3-axes accelerations. In our case studies, a set of accelerometers were attached to corresponding body parts to detect involuntary movements. The results indicate that the RMS values became higher when conspicuous involuntary movements observed. Special attention is paid to analyzing the RMS values in touch panel adaptation.