Biomechanical Characterization of the Hand Touch Corrective Behavior of the Frail Elderly During Bed Egress

Details

• Personal Author:
  Merryweather A ; Morse J ; Tatom A ; Taylor D
• Description:
  Introduction: According to the National Council on Aging, within the United States, falls are the leading cause of fatal and non-fatal injuries among the elderly. Studies indicate that the elderly are most likely to fall during weight transitioning, such as during sit-to-stand. While studies have been done to determine what factors (both intrinsic and extrinsic) may influence the likelihood that an elderly person may fall, these have often been a simulated fall in a laboratory with healthy adults which have been shown to be quite different from a real-world fall. A better understanding of biomechanical factors of real-world falls, including any attempts at correcting balance before or during a fall, could assist in predicting the conditions just prior to a fall. This knowledge would provide the ability not only to identify falls in a laboratory setting, but also would provide a basis for more appropriate interventions to prevent falls of the frail elderly in their living environments. Thus, there is a critical need to understand the balance recovery strategies in frail elderly and their role in fall prevention. Methods: This study looks at the specific task of sit-to-stand to walk from a hospital bed. Corrective behaviors (CBs) are defined, biomechanically characterized, and identified for each trial. The data set consists of 88 elderly subjects with over 1400 unique trials. An 18-camera motion tracking system was used to track full-body biomechanics. Participants exited an adjustable, instrumented hospital bed with three bed rail conditions and three bed height conditions. Each subject performed a sit-to-stand to walk transition from bedside. A corrective behavior (CB) was defined as a behavior which establishes a Point of Contact (POC) with a stable surface to regain or maintain stability. Specifically, for this study the hand touch CB is the movement of the hand, including touching chair armrests, bed rail, or mattress, to maintain or regain stability. A random sample of thirteen subjects was used from the large data set for this pilot study. Key biomechanical stability metrics were calculated for each trial, as follows: BOS area, COM proximity to the BOS perimeter, COM Time to Contact (TtC) the BOS perimeter, and COM Jerk. Results: From the 13 subjects trials, we identified 209 hand touch CBs. Initial results from this indicate Hand CB/POCs are readily identifiable when the velocity of the wrist is equal to approximately zero. The Jerk of the COM was found to be zero at all key BOS transitions. However, a significant jerk occurred during IS. We anticipate that the additional biomechanical attributes we will review will also be indicators of a fall/near fall, such as a threshold value for the COM proximity to the BOS perimeter. These biomechanical attributes will then be used to establish an automated process to review the remaining trials. Conclusion: The sit-to-stand transition is a challenging task for the frail elderly. Strategies typically employed by the frail elderly to achieve standing require the implementation of corrective behaviors to maintain balance and/or recover from imbalances that occur during this weight shifting transition. Our results suggest that corrective behaviors are effective in indicating either an assist or a fall/near fall. With further work, a model of fall-initiation of the frail elderly will be developed to provide key biomechanical stability measures for use as a proxy for a fall in laboratory studies, as well as to provide new insights in fall intervention. [Description provided by NIOSH]
• Subjects:
  Accidental Falls Accidents Age Factors Aging Biomechanical Phenomena Hospitals Occupational Health Safety
• Keywords:
  Age Factors Age Groups Biomechanical Modeling Biomechanics Fall Protection Falls Hospital Equipment Injury Prevention
• Publisher:
  The University of Utah
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 8 ; Utah
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  22
• NIOSHTIC Number:
  nn:20052093
• Citation:
  16th Annual Regional National Occupational Research Agenda (NORA) Young/New Investigators Symposium, April 19-20, 2018, Salt Lake City, Utah. Salt Lake City, UT: The University of Utah, 2018 Apr; :22
• Federal Fiscal Year:
  2018
• Performing Organization:
  University of Utah
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  16th Annual Regional National Occupational Research Agenda (NORA) Young/New Investigators Symposium, April 19-20, 2018, Salt Lake City, Utah
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9363c44ebca11628e5b9d898a0a8059faecc912707695031a7d108ce0c986a20622167275a36b09f1aac72b5132c1fc317c004c4bb129fa5f11ce36acd1cdf5d
• Download URL:
  https://stacks.cdc.gov/view/cdc/211692/cdc_211692_DS1.pdf
• File Type:
  [PDF - 43.10 KB ]