Characteristics of landings, rotations, and impacts of real-world falls captured by wearable sensors in older persons

Abstract

Falls are a significant health problem. Approximately 30% of adults 65 and older fall each year. Understanding the characteristics of fall patterns, including landing, impact, and related injuries, is of paramount importance to understand why and when injuries happen and implement adequate interventions to reduce the risk of adverse consequences . We analyzed real-world falls of older persons living in different settings to characterize the landing positions, related impacts, and injuries. We analyzed real-world falls from the Farseeing dataset [1], recorded by a wearable sensor worn on the lower back. We selected only those falls with a clear upright pre-fall position. We processed Accelerations and angular velocities to estimate landing positions and the amount of rotation during the descent phase. We computed the prevalence of different types of landings and associated these quantitative characteristics with the reported injuries. Finally, we estimated the impact force using the body mass of the subject and the maximum value of the acceleration norm. We analyzed 92 falls in total. The landing positions were divided into backwards (BW), forwards (FW), and sideways (SW). The majority of falls were BW (67%), followed by SW (25%) and FW (8%), in accordance with [2]. BW falls were the ones with fewer injuries in percentage, also in accordance with [2]. Only two serious injuries happened, one in FW and one in SW. The highest rotation was found around the vertical direction V (see Fig. 1.a)). Estimated impact forces were between 1000 and 5000 Newton, with a slightly higher impact force for falls with backward landing. Through automatic analysis of wearable sensor data, it was possible to identify different patterns of real-world falls of older people, getting novel insights about the prevalence of different landing positions, associated injuries, movements during descent (i.e., rotations), and fall impact forces. The backward landing was the most frequent landing position, with the lowest relative number of associated injuries (both minor and serious injuries).