title: Higher order balance control: Distinct effects between cognitive task and manual steadiness constraint on automatic postural responses.
abstract: In the present experiment, we aimed to evaluate the interactive effect of performing a cognitive task simultaneously with a manual task requiring either high or low steadiness on APRs. Young volunteers performed the task of recovering upright balance following a mechanical perturbation provoked by unanticipatedly releasing a load pulling the participant's body backwards. The postural task was performed while holding a cylinder steadily on a tray. One group performed that task under high (cylinder' round side down) and another one under low (cylinder' flat side down) manual steadiness constraint. Those tasks were evaluated in the conditions of performing concurrently a cognitive numeric subtraction task and under no cognitive task. Analysis showed that performance of the cognitive task led to increased body and tray displacement, associated with higher displacement at the hip and upper trunk, and lower magnitude of activation of the GM muscle in response to the perturbation. Conversely, high manual steadiness constraint led to reduced tray velocity in association with lower values of trunk displacement, and decreased rotation amplitude at the ankle and hip joints. We found no interactions between the effects of the cognitive and manual tasks on APRs, suggesting that they were processed in parallel in the generation of responses for balance recovery. Modulation of postural responses from the manual and cognitive tasks indicates participation of higher order neural structures in the generation of APRs, with postural responses being affected by multiple mental processes occurring in parallel.
authors: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo, 05508-030, Brazil. Electronic address: daniboari@usp.br.
authors: Daniel Boari
authors: DB
authors: Coelho
authors: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo, 05508-030, Brazil. Electronic address: bourlinova@usp.br.
authors: Catarina
authors: C
authors: Bourlinova
authors: Human Motor Systems Laboratory, School of Physical Education and Sport, University of São Paulo, 05508-030, Brazil. Electronic address: lateixei@usp.br.
authors: Luis Augusto
authors: LA
authors: Teixeira
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006613:Higher Nervous Activity / Q000502:physiology; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
keywords: Multitasking; Perturbed posture; Postural control; Postural reactions; Stance perturbation