The Slippery Slope Between Falling And Recovering: An Examination Of Sensory And Somatic Factors Influencing Recovery After A Slip

Background: Slips and falls account for large rates of injury and mortality in multiple populations. During an unexpected slip, sensory mechanisms are responsible for signaling the slip to the central nervous system, and a series of corrective responses is generated to arrest the slip and prevent a fall. While previous research has examined the corrective responses elicited, the answer of how these systems break down during a fall remains elusive. Purpose: To examine differences in postural control (slip detection), lower extremity corrective responses (slip recovery), and cortical control of the slip recovery response between individuals who fall and those who recover. Methods: One hundred participants were recruited for this study (50 males & 50 females). Participant’s gait kinematics and kinetics were collected during normal gait (NG) and an unexpected slip (US). The slip was classified as a fall or recovery, and by slip severity. Once classified, postural control, reaction times, corrective moments, and cortical contribution were examined between groups using ANOVAs and independent t-tests. Additionally, prediction equations for slip outcome, and slip severity were created using a binary logistic regression model. Slip Detection Results: Postural sway when the proprioceptive (OR = 0.02, CI: 0.01-1.34) and vestibular (OR = 0.60, CI: 0.26-1.39) systems are stressed were negatively associated with odds of falling. While postural sway when the visual system was stressed (OR = 3.18, CI: 0.887-11.445) was positively associated with odds of falling. Slip Recovery Results: Increased time to peak hip extension (OR = 1.006, CI: 1.00-1.01) and ankle dorsiflexion (OR = 1.005, CI: 1.00-1.01) moments increased the odds of falling. While the average ankle moment was negatively associated with falling (OR = 0.001, CI: 0.001-0.005). Cortical Contribution Results: Spectral power in the Piper frequency band was increased in US trials compared to NG. Further, fallers exhibited an increase in cortical activity compared to those who recovered. Conclusions: Rapid lower extremity corrective responses appear critical in arresting the slip and preventing a fall, and the temporal nature of this response may depend on slip detection and subsequent response selection. Moreover, our results suggest that more severe slips may require increased activation of higher centers of the motor cortex.

Name thesis:degree_name

Ph.D. in Health and Kinesiology

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Health, Exercise Science, and Recreation Management

Year dc:date.available

2018

Author dc:creator

• Wilson, Samuel J.

Contributors dc:contributor

• Dwight E. Waddell
• John C. Garner
• John P. Bentley

• Balance
• Falls
• Gait
• Slips
• Biomechanics

Repository record dc:identifier

https://egrove.olemiss.edu/etd/610

OAI identifier oai:identifier

oai:egrove.olemiss.edu:etd-1609