Date of Award

5-2019

Degree Type

Creative Project

Degree Name

Master of Science (MS)

Department

Kinesiology and Health Science

First Advisor

David Bolton

Second Advisor

Chris Dakin

Third Advisor

Brennan Thompson

Abstract

Response inhibition involves stopping undesired and automatic actions allowing for behavioral flexibility. This ability is theoretically able to contribute to fall prevention, which older adults are known to have difficulty with. Although much has been learned from cognitive psychology regarding response inhibition, translation to the challenge of balance recovery is unclear. Recently a correlation has been found between performance on a standard test of response inhibition called the Stop Signal Task (SST) and a balance test that required inhibition of a reactive step in young adults. This highlights a neural mechanism for stopping action across different behavioral contexts in young adults. The present study was conducted to determine if this relationship was similarly evident in older adults. A group of 19 older adults (50-85 years) performed the SST and reactive balance test separately. The SST evaluates an individual’s ability to suppress a visually-cued button press upon hearing a “Stop” tone, and measures the response inhibition speed called the Stop Signal Reaction Time (SSRT). Reactive balance was tested by releasing participants from a supported lean position, where the environment was changed during visual occlusion. Upon receiving vision, participants were required to step to regain balance, or suppress a step when obstacles were present. The stepping muscle responses between the “step” and “no step” trials were compared to quantify step suppression. Results indicated that SSRT was correlated with muscle activation in the stance leg. More specifically, individuals with faster SSRTs were also better at inhibiting leg muscle activation on no step trials. Present results suggest the ability to inhibit finger responses in a seated cognitive test reflects an individual’s capacity for response inhibition, which is preserved in a whole-body, balance recovery task. Potentially, response inhibition via the SST could identify a risk factor leading to falls and have clinical application.

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