Classification of Health Literacy and Cognitive Impairments Using Higher-Order Kinematic Parameters of the Sit-to-Stand Movement From a Monostatic Doppler Radar

To develop daily monitoring systems that can identify elderly people with cognitive functioning and health literacy impairments, this study examined elderly participants during the sit-to-stand (STS) movement by using a Doppler radar to gather kinematic information for assessing any associations between those data and factors related to both cognitive functioning and health literacy. More specifically, we used Doppler radar systems to measure kinematic parameters related to the STS movement among 170 community-dwelling elderly participants aged 65 years and older, who were classified into good or bad health literacy groups and cognitive-healthy or cognitive- impairment groups based on the results of conventional paper-based tests designed to assess health literacy and cognitive functioning, respectively. The Doppler radar measured kinematic parameters for not only velocity, acceleration, and jerk (the time derivative of acceleration), but also higher-order derivative parameters: snap (the time derivative of jerk) and crackle (the time derivative of snap). Intergroup differences between the measured kinematic parameters were then compared using Welch's t-test. The results revealed that health literacy impairments were associated with velocity, acceleration, and jerk, while cognitive impairments were associated with the higher-order derivative parameters, snap and crackle. These findings show that the Doppler radar is an effective tool to distinguish impairments between health literacy and cognitive functioning based on the extraction of higher-order derivative parameters during the STS movement. The results should lead to the development of unconstrained monitoring systems that can detect early signs of impairments in both cognitive functioning and health literacy among the elderly.