Lower Cognitive Set Shifting Ability Is Associated With Stiffer Balance Recovery Behavior and Larger Perturbation-Evoked Cortical Responses in Older Adults

• Type of Material: Article
• Authors: Aiden M Payne, Emory University; Jacqueline A Palmer, Emory University; Johnathan McKay, Emory University; Lena Ting, Emory University
• Language: English
• Date: 2021-12-06
• Publisher: FRONTIERS MEDIA SA
• Publication Version: Final Published Version
• Copyright Statement: © 2021 Payne, Palmer, McKay and Ting.
• Final Published Version (URL): http://dx.doi.org/10.3389/fnagi.2021.742243
• Title of Journal or Parent Work: FRONTIERS IN AGING NEUROSCIENCE
• Volume: 13
• Start Page: 742243
• End Page: 742243
• Grant/Funding Information: This work was supported by the National Institutes of Health (Eunice Kennedy Shriver National Institute of Child Health and Human: R01 HD46922, F32 HD096816; National Institute of Neurological Disorders and Stroke: P50 NS 098685; National Center for Advancing Translational Sciences: UL1 TR000424), the Fulton County Elder Health Scholarship (2015–2017), and the Zebrowitz Award (2018).
• Keywords: IMPAIRMENT; FALLS; STIMULATION; Neurosciences; antagonist; Neurosciences & Neurology; motor; STANDING BALANCE; Geriatrics & Gerontology; posture; aging; Science & Technology; cocontraction; Life Sciences & Biomedicine; YOUNG; POSTURAL RESPONSES; MOTOR; cortex; WALKING; EEG; ACTIVITY REFLECTS; TASK
• Research Categories: Engineering, Biomedical; Health Sciences, Rehabilitation and Therapy

Abstract

The mechanisms underlying associations between cognitive set shifting impairments and balance dysfunction are unclear. Cognitive set shifting refers to the ability to flexibly adjust behavior to changes in task rules or contexts, which could be involved in flexibly adjusting balance recovery behavior to different contexts, such as the direction the body is falling. Prior studies found associations between cognitive set shifting impairments and severe balance dysfunction in populations experiencing frequent falls. The objective of this study was to test whether cognitive set shifting ability is expressed in successful balance recovery behavior in older adults with high clinical balance ability (N = 19, 71 ± 7 years, 6 female). We measured cognitive set shifting ability using the Trail Making Test and clinical balance ability using the miniBESTest. For most participants, cognitive set shifting performance (Trail Making Test B-A = 37 ± 20 s) was faster than normative averages (46 s for comparable age and education levels), and balance ability scores (miniBESTest = 25 ± 2/28) were above the threshold for fall risk (23 for people between 70 and 80 years). Reactive balance recovery in response to support-surface translations in anterior and posterior directions was assessed in terms of body motion, muscle activity, and brain activity. Across participants, lower cognitive set shifting ability was associated with smaller peak center of mass displacement during balance recovery, lower directional specificity of late phase balance-correcting muscle activity (i.e., greater antagonist muscle activity 200–300 ms after perturbation onset), and larger cortical N1 responses (100–200 ms). None of these measures were associated with clinical balance ability. Our results suggest that cognitive set shifting ability is expressed in balance recovery behavior even in the absence of profound clinical balance disability. Specifically, our results suggest that lower flexibility in cognitive task performance is associated with lower ability to incorporate the directional context into the cortically mediated later phase of the motor response. The resulting antagonist activity and stiffer balance behavior may help explain associations between cognitive set shifting impairments and frequent falls.