Monitoring gait patterns and functional activities in community dwelling elderly at risk for falls

With the process of aging movement patterns are altered, increasing the risk of falls and introducing functional limitations in the elderly daily living. Falls are the leading cause of death from injuries and the most common cause of non-fatal injuries, and hospitalization for trauma in elderly. In addition to aging, a history of falls increases the risk of further falling incidents, with both effects decreasing the stability and flexibility of the elderly gait patterns. Reduced stability in the gait pattern is observed in an increase in the variability of the movement pattern, and reduced flexibility is observed in inability of the elderly to change coordination pattern in response to a change in the task demand (e.g. increasing walking speed). In this dissertation, the objective of the first study was to characterize the differences in gait parameters and coordination patterns between elderly fallers (EF), elderly non-fallers (ENF) and young adults (YA), effected by history of falls and aging. Both elderly groups showed a decrease in flexibility in utilizing stride parameters and coordination patterns in response to a systematic manipulation of walking speed compared to YA. Both elderly groups and EF in particular showed a significant increase in variability of stride parameters, mean relative phase between limb and mean Relative Power Index (RPI) compared to YA. While EF reduce variability in their gait parameters by increasing stride frequency (SF) at slow walking speeds (<1m/sec), they increase the variability in those parameters and in relative phase between limbs at faster walking speeds (>1m/sec), and at prolonged walking periods. These gait changes might be putting the elderly at further risk for falls and functional limitations. To monitor these changes in movement patterns that lead to further instability and functional limitations, the objective of study 2 was to evaluate the accuracy of a Functional Activity Monitor (FAM) in 1) detecting daily activities including postures, transfers between postures and walking, and in 2) measuring activity duration and step frequency. Study 2 has a cross-sectional design, comparing the outcomes of the FAM to 1) video recordings for activity identification and activity duration, and to 2) 3D motion analysis system recordings for measuring step frequencies at different walking speeds. The FAM includes a tri-axial accelerometer, and a tri-axial gyroscope powered by 3.7V lithium ion battery. The participants in study 2 were ten young adults, screened and excluded for functional limitations and were instructed to perform multiple daily functional activities in a lab setting. One FAM was positioned on the sternum of the participants and one on each of their thigh. Wireless transmission of data to a Personal Digital Assistant (PDA) was established by means of Bluetooth. Results showed an agreement between instruments for activities identification ranging from 96.2% to 100% for all activities. There was no significant difference between instruments in activity duration and step frequencies at different walking speeds. The FAM can be considered an accurate device to monitor daily functional activities, activity durations and step frequencies of healthy YA in research laboratory settings. Future research should be focused on the validation of the FAM in evaluating daily activities and movement patterns of elderly with functional limitations and at risk for falls, in their home and community settings.