AGING EFFECTS OF MOTOR PREDICTION ON PROTECTIVE BALANCE AND STARTLE RESPONSES TO SUDDEN DROP PERTURBATIONS. (16th November 2018)

• Record Type: Journal Article
• Authors: Sanders, O; Hsiao, H; Savin, D; Creath, R; Rogers, M
• Is Part Of: Innovation in aging. Volume 2(2018)Supplement 1
• Page Start: 893
• Page End: 893
• Publication Date: 2018-11-16
• Subjects: Aging -- Periodicals; Gerontology -- Periodicals; 612.67
• DOI: 10.1093/geroni/igy031.3327
• Languages: English
• ISSNs: 2399-5300

Abstract

Abstract: This study investigated the modulatory effects of self-triggered drop perturbations (SLF) on reducing startle-like first trial response (FTR) magnitude evoked by externally-triggered (EXT) drop perturbations in younger and older adults. Ten healthy older (71.4 ± 1.44 years) and younger adults (26.2 ± 1.63 years) stood atop a moveable platform and received blocks of twelve consecutive EXT and SLF drop perturbations. Following the last SLF trial, participants received an additional EXT trial spaced 20 minutes apart to assess retention (EXT RTN) of any modulation effects. Electromyographic (EMG) activity was recorded bilaterally over the sternocleidomastoid (SCM), vastus lateralis (VL), biceps femoris (BF), medial gastrocnemius (MG), and tibialis anterior (TA). Whole-body kinematics and kinetic data were recorded with motion analysis. Stability in the antero-posterior direction was quantified using the margin of stability (MoS). Younger and older adults showed reduced SCM peak amplitude responses during SLF and EXT RTN trials. VL/BF and TA/MG coactivation were reduced during SLF FTR compared to EXT FTR (p<0.05) with reduced peak vGRFs both younger and older adults (p<0.05). Older adults increased their MoS during SLF FTR compared to EXT FTR (p<0.05). Both groups performed more eccentric work during SLF trials compared to EXT (p<0.05). These findings indicated that abnormal startle effects with aging may interfere with balance recovery and increase risk of injury with external balance perturbations. Motor prediction may be used to acutely mitigate abnormal startle/postural responses with aging.