Control of static posture is constrained by multiple sensory inputs, motor ability, and task constraints. Development of static postural control across the lifespan can be analyzed effectively using nonlinear analyses of center of pressure (CoP) time series, including approximate and sample entropy. In this paper, the key findings from studies using nonlinear analysis tools are reviewed to describe the development of postural control. Preschool children learn to adopt relatively unstable postures (e.g., standing) in which the regularity of CoP initially increases as a consequence of restricting mechanical degrees of freedom. As children age, CoP regularity decreases as degrees of freedom are released, thus enabling a more functional, adaptable type of postural control. Changes to sensory inputs or task constraints also affect the regularity of CoP sway. For example, removing vision, adding vibration, or imposing dual-task conditions affect performer’s CoP regularity differently. One limitation of approximate and sample entropy analysis is the influence of different input parameters on the output and subsequent interpretation. Ongoing refinement to entropy analysis tools concern determining appropriate values for the length of sequence to be matched and the tolerance level used with CoP data.
Neil Anderson and Chris Button
Haidzir Manaf, Maria Justine and Hui-Ting Goh
Attentional loadings deteriorate straight walking performance for individuals poststroke, but its effects on turning while walking remain to be determined. Here we compared turning kinematics under three attentional loading conditions (single, dual-motor, and dual-cognitive task) between stroke survivors and healthy controls. Nine chronic stroke survivors and 10 healthy controls performed the Timed Upand- Go test while their full-body kinematics were recorded. Onset times of yaw rotation of the head, thorax and pelvis segments and head anticipation distance were used to quantify turning coordination. Results showed that stroke survivors reoriented their body segments much earlier than the controls, but they preserved the similar segmental reorientation sequence under the single-task condition. For the healthy controls, attentional loading led to an earlier axial segment reorientation, but the reorientation sequence was preserved. In contrast, the dual-cognitive task condition led to a disrupted reorientation sequence in stroke. The results indicate that turning coordination was altered in individuals poststroke, especially under the dual-task interference.
Richard Mullen, Lew Hardy and Andrew Tattersall
The aim of this study was to examine the conscious processing hypothesis as an explanation of the anxiety/performance relationship. The study was designed to identify conscious processing performance effects while controlling for an alternative attentional threshold explanation identified in previous research. Participants completed 60 golf putts. They completed 3 blocks of 10 putts in single task, task-relevant shadowing, and task-irrelevant tone-counting conditions. Each set of 3 × 10 putts was completed in low and high anxiety conditions. Anxiety was elevated using an instructional set. Self-reported effort and spectral analysis of heart rate variability were used to examine the patterning of effort across the different putting conditions. Findings indicated that performance was impaired in the high anxiety shadowing and tone-counting conditions, supporting an attentional threshold interpretation. Spectral analysis of heart rate variability indicated that potential compensatory increases in spectral power in the high frequency band associated with dual-task putting in the low anxiety condition were absent in the high anxiety tone-counting and shadowing putting conditions, partially reflecting the performance findings. No effects were found for self-reported effort. Taken together, the performance and heart rate variability results support an attentional interpretation of the anxiety/motor performance relationship.
Brooke Castaneda and Rob Gray
This study addressed the question, what should baseball players focus their attention on while batting? Less-skilled and highly skilled (college) baseball players participated in four dual-task conditions in a baseball batting simulation: two that directed attention to skill execution (skill/internal [movement of the hands] and skill/external [movement of the bat]) and two that directed attention to the environment (environmental/irrelevant [auditory tones] and environmental/external [the ball leaving the bat]). Batting performance for highly skilled players was best in the environmental/external condition and worst in the skill/internal condition. Performance of less-skilled batters was significantly better in the two skill conditions than in either of the two environmental conditions. We conclude that the optimal focus of attention for highly skilled batters is one that does not disrupt proceduralized knowledge and permits attention to the perceptual effect of the action, whereas the optimal focus of attention for less-skilled batters is one that allows attention to the step-by-step execution of the swing.
Manuel E. Hernandez, Erin O’Donnell, Gioella Chaparro, Roee Holtzer, Meltem Izzetoglu, Brian M. Sandroff and Robert W. Motl
al., 2016 ). Of note, concurrent cognitive and walking tasks might compound the risk for falling in older adults with MS beyond what would be expected by dual tasking and aging with MS by themselves. The decline in normal, functional gait patterns can be very challenging for persons with MS and can
Kelsey Picha, Carolina Quintana, Amanda Glueck, Matt Hoch, Nicholas R. Heebner and John P. Abt
Dynavision protocols within a healthy, adult population. This study has expanded time frames and protocols that can be used reliably for assessment in clinical practice. The protocols used in this study stress additional cognitive load similar to the dual tasking required of athletes during game play
Susan J. Leach, Joyce R. Maring and Ellen Costello
interventions to promote function and mitigate the motor and cognitive declines associated with aging should ideally incorporate dual-task (DT) demands. Theories related to procedural learning further support the effectiveness of DT interventions in that acquisition of new skills is best accomplished when the
Kevin A. Becker, Ayana F. Georges and Christopher A. Aiken
other attentional strategies can be used to avoid conscious control of movement. Beilock et al. ( 2002 ) proposed a dual-task condition as a means of keeping attention away from movement control. Participants were asked to either use what they called a skill focus (e.g., monitoring the side of the foot
Juliana Hotta Ansai, Larissa Pires de Andrade, Paulo Giusti Rossi, Theresa Helissa Nakagawa, Francisco Assis Carvalho Vale and José Rubens Rebelatto
disorders ( 5th ed. ). Washington, DC : American Psychiatric Association . Ansai , J.H. , Andrade , L.P. , Rossi , P.G. , Takahashi , A.C.M. , Vale , F.A.C. , & Rebelatto , J.R. ( 2017 ). Gait, dual task and history of falls in elderly with preserved cognition, mild cognitive impairment and
Daniel M. Grindle, Lauren Baker, Mike Furr, Tim Puterio, Brian Knarr and Jill Higginson
cell phone, than an older population who may perform more poorly due to lack of experience. For example, the dual task of memorizing word lists while walking becomes more difficult with age, 11 suggesting older subjects may respond differently to a walking workstation. Furthermore, the cognitive and