Development and Integration of Accelerometery and Force Plate Systems for Enhanced Measurement of Orthostatic Postural Stability in Older Adults

Abstract

This Master’s thesis investigates the feasibility and clinical utility of using accelerometry and force balance plate (FBP) systems to assess orthostatic postural stability in older adults during the Active Stand (AS) test. Traditionally used to evaluate autonomic cardiovascular function, the AS test is applied here as a novel framework for assessing postural control, particularly in populations at risk of falling.

The research was conducted in two distinct phases. Phase One involved secondary analysis of accelerometry data collected from 26 older adults attending a Falls and Syncope Unit. An accelerometer placed anteriorly at the waist measured motion during three predefined regions of interest (ROIs) within the AS test. The analysis revealed that participants with a history of smoking showed significantly higher postural motion in both the supine rest and recovery phases, suggesting a possible link between smoking-related physiological changes and impaired postural control.

Phase Two involved a pilot study with 10 older adults, where force plate data were collected during AS testing in a gait laboratory. Two postural sway metrics—sway area and 95% prediction ellipse area—were examined. Although accelerometer-based findings were not replicated with FBP data, a significant interaction was observed between orthostatic hypotension at 40 seconds post-stand (OH40) and increased ellipse area during the recovery phase. This suggests that FBPs may be sensitive to prolonged postural instability in this clinical subgroup.

Despite limitations including small sample sizes and pilot design, the study supports the complementary use of accelerometers and FBPs in capturing different aspects of postural dynamics. These findings contribute preliminary evidence to inform future research aiming to enhance fall risk assessment in clinical settings through sensor-based technologies.