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Anticipatory Postural Adjustment

Roshanth Rajachandrakumar, Julia E Fraser, Alison Schinkel-Ivy, Elizabeth L Inness, Lou Biasin, Karen Brunton, William E McIlroy, Avril Mansfield
Anticipatory postural adjustments, executed prior to gait initiation, help preserve lateral stability when stepping. Atypical patterns of anticipatory activity prior to gait initiation may occur in individuals with unilateral impairment (e.g., stroke). This study aimed to determine the prevalence, correlates, and consequences of atypical anticipatory postural adjustment patterns prior to gait initiation in a sub-acute stroke population. Forty independently-ambulatory individuals with sub-acute stroke stood on two force plates and initiated gait at a self-selected speed...
December 21, 2016: Gait & Posture
Yun Wang, Kazuhiko Watanabe, Tadayoshi Asaka
PURPOSE: We explored changes in muscle interactions during healthy aging as a window into neural control strategies of postural preparation to action/perturbation. In particular, we quantified the strength of multi-muscle synergies stabilizing the center of pressure (COP) displacement during the preparation for making a step associated with support surface translations. METHODS: Young and elderly subjects were required to make a step in response to support surface perturbations...
December 21, 2016: European Journal of Applied Physiology
Romain Tisserand, Thomas Robert, Pascal Chabaud, Marc Bonnefoy, Laurence Chèze
In the case of disequilibrium, the capacity to step quickly is critical to avoid falling in elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT), where elderly fallers (F) take longer to step than elderly non-fallers (NF). However, the reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA) that elderly F develop in a stepping context and their consequences on the dynamic stability...
2016: Frontiers in Human Neuroscience
Daniele Piscitelli, Ali Falaki, Stanislaw Solnik, Mark L Latash
We explored two aspects of feed-forward postural control, anticipatory postural adjustments (APAs) and anticipatory synergy adjustments (ASAs) seen prior to self-triggered unloading with known and unknown direction of the perturbation. In particular, we tested two main hypotheses predicting contrasting changes in APAs and ASAs. The first hypothesis predicted no major changes in ASAs. The second hypothesis predicted delayed APAs with predominance of co-contraction patterns when perturbation direction was unknown...
November 19, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Hugo Massé-Alarie, Louis-David Beaulieu, Richard Preuss, Cyril Schneider
Hemispheric lateralization of pain processing was reported with overactivation of the right frontal lobe. Specifically in chronic low back pain (CLBP), functional changes in the left primary motor cortex (M1) with impaired anticipatory postural activation (APA) of trunk muscles have been observed. Given the connections between frontal and M1 areas for motor planning, it is hypothesized that the pain side could differently influence M1 function and APA of paravertebral multifidus (MF) muscles. This study aimed at testing whether people with right- versus left-sided CLBP showed different M1 excitability and APA...
November 15, 2016: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Gregor Brecl Jakob, Olena Pelykh, Annika Plate, Zuzana Košutzká, Zvezdan Pirtošek, Maja Trošt, Joseph Ilmberger, Peter Valkovic, Jan H Mehrkens, Kai Bötzel
BACKGROUND: Dystonia is a movement disorder with patterned, directional, and often sustained muscle contractions that produce abnormal postures or repetitive movements. Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective and safe treatment for medically refractory dystonia. However, recent studies reported gait problems, gait freezing and falls in patients treated with DBS. Because these symptoms may point to deficient gait initiation processes, we systematically assessed the anticipatory postural adjustments (APAs) prior to stepping in dystonia patients with GPi-DBS...
January 1, 2017: Neuroscience Letters
Gianluca Bonora, Martina Mancini, Ilaria Carpinella, Lorenzo Chiari, Fay B Horak, Maurizio Ferrarin
People with Parkinson's disease (PD) typically demonstrate impaired anticipatory postural adjustments (APAs) that shift the body center of mass forward (imbalance) and over the stance leg (unloading) prior to gait initiation. APAs are known to be smallest when people with PD are in their OFF-medication state compared to ON-medication or healthy controls. The aim of this pilot study is to validate a previously developed method for the assessment of gait initiation on PD patients in OFF state with body-worn, inertial sensors...
January 2017: Gait & Posture
G Brecl Jakob, T Remšak, S Šega Jazbec, A Horvat Ledinek, U Rot
Balance and cognition are affected by multiple sclerosis (MS). Cognitive-motor interference (CMI) is important for balance impairment in MS, however little is known about CMI at the earliest stages of the disease. Step initiation (SI) with anticipatory postural adjustments (APAs) has been linked to postural instability and falls in subjects with MS, therefore we aimed to assess CMI between SI and the two storage systems of working memory in patients with clinically isolated syndrome (presented as optic neuritis-ON) suggestive of MS...
January 2017: Gait & Posture
Paolo Cavallari, Francesco Bolzoni, Carlo Bruttini, Roberto Esposti
Anticipatory Postural Adjustments (APAs) are commonly described as unconscious muscular activities aimed to counterbalance the perturbation caused by the primary movement, so as to ensure the whole-body balance, as well as contributing to initiate the displacement of the body center of mass when starting gait or whole-body reaching movements. These activities usually create one or more fixation chains which spread over several muscles of different limbs, and may be thus called inter-limb APAs. However, it has been reported that APAs also precede voluntary movements involving tiny masses, like a flexion/extension of the wrist or even a brisk flexion of the index-finger...
2016: Frontiers in Human Neuroscience
Florian Monjo, Nicolas Forestier
Muscle fatigue modifies the gain between motor command magnitude and the mechanical muscular response. In other words, post-fatigue, central drives to the muscles must increase to maintain a particular submaximum mechanical output. In this study, we tested the hypothesis that this modified gain can be predicted by the central nervous system (CNS) during discrete ballistic movements. In two separate experiments, subjects were required to perform shoulder flexions in standing and sitting positions at submaximum target peak accelerations...
December 17, 2016: Neuroscience
Alison Pienciak-Siewert, Dylan P Horan, Alaa A Ahmed
Classical theories of motor learning hypothesize that adaptation is driven by sensorimotor error; this is supported by studies of arm and eye movements that have shown that trial-to-trial adaptation increases with error. Studies of postural control have shown that anticipatory postural adjustments increase with the magnitude of a perturbation. However, differences in adaptation have been observed between the two modalities, possibly due to either the inherent instability or sensory uncertainty in standing posture...
December 1, 2016: Journal of Neurophysiology
Jeong-Ho Park, Martina Mancini, Patricia Carlson-Kuhta, John G Nutt, Fay B Horak
Although balance and gait deteriorate as a person ages, it is unknown if all balance and gait measures change similarly across the adult age span. We developed the Instrumented Stand and Walk test (ISAW) to provide a quick quantification of key components of balance and walking: postural sway, anticipatory postural adjustments during step initiation, gait, and turning using body-worn, inertial sensors. Our aims were to characterize how different balance and gait measures change with age and to identify key age-related measures of mobility, in a wide age range of healthy, community-dwelling adults...
December 1, 2016: Experimental Gerontology
Jean-Louis Honeine, Marco Schieppati, Oscar Crisafulli, Manh-Cuong Do
Gait initiation (GI) involves passing from bipedal to unipedal stance. It requires a rapid movement of the center of foot pressure (CoP) towards the future swing foot and of the center of mass (CoM) in the direction of the stance foot prior to the incoming step. This anticipatory postural adjustment (APA) allows disengaging the swing leg from the ground and establishing favorable conditions for stepping. This study aimed to describe the neuro-mechanical process that underlies the goal-directed medio-lateral (ML) APA...
2016: Frontiers in Human Neuroscience
Ângela Fernandes, Andreia S P Sousa, Nuno Rocha, João Manuel R S Tavares
The aim of this study was to compare postural control strategies during gait initiation in single- and dual-task conditions in individuals in early stages of Parkinson´s Disease (PD). The activation timing of tibialis anterior occurred significantly later in the individuals with PD than in the controls (p=0.05), and a significant interaction between the groups, conditions and limbs was found (p=0.027). Differences between the single- and dual-task conditions were observed for the activation timing of the tibialis anterior (p=0...
August 19, 2016: Motor Control
Angel L Phanthanourak, Taylor W Cleworth, Allan L Adkin, Mark G Carpenter, Craig D Tokuno
This study examined how postural threat in the form of a potential perturbation affects an individual's ability to perform a heel raise. Seventeen adults completed three conditions: i) low threat, where participants performed a heel raise in response to a "go" tone, ii) high threat, where participants either heard the same "go" tone, for which they performed a heel raise, or experienced a support surface translation in the medio-lateral direction that disturbed their balance, and iii) choice reaction time task, where participants either completed a heel raise in response to the same "go" tone or a toe raise in response to a lower pitched tone...
September 3, 2016: Gait & Posture
Carlo Bruttini, Roberto Esposti, Francesco Bolzoni, Paolo Cavallari
It is a common experience to exhibit a greater dexterity when performing a pointing movement with the preferred limb (PREF) vs. the non-preferred (NON-PREF) one. Here we provide evidence that the higher precision in pointing movements of the PREF vs. NON-PREF hand is associated with an earlier occurrence of the anticipatory postural adjustments (APAs). In this aim, we compared the APAs which stabilize the left or the right arm when performing a pen-pointing movement (prime mover flexor carpi radialis (FCR))...
2016: Frontiers in Human Neuroscience
Soufien Chikh, Eric Watelain, Arnaud Faupin, Antonio Pinti, Mohamed Jarraya, Cyril Garnier
Voluntary movement often causes postural perturbation that requires an anticipatory postural adjustment to minimize perturbation and increase the efficiency and coordination during execution. This systematic review focuses specifically on the relationship between the parameters of anticipatory muscular activities and movement finality in sitting position among adults, to study the adaptability and predictability of anticipatory muscular activities parameters to different movements and conditions in sitting position in adults...
August 2016: Perceptual and Motor Skills
Sandy McCombe Waller, Chieh-Ling Yang, Laurence Magder, Don Yungher, Vicki Gray, Mark W Rogers
Movement preparation of both anticipatory postural adjustments (APAs) and goal directed movement during a standing reaching task in adults with chronic hemiparesis and healthy controls was investigated. Using a simple reaction time paradigm, while standing on two separate force platforms, subjects received a warning light cue to "get ready to reach" followed 2.5s later by an imperative light cue to "reach as quickly as possible" with the paretic arm (matched arm for controls) to touch a target in front of them for a total of 90 trials...
September 6, 2016: Neuroscience Letters
Hidehito Tomita, Yoshiki Fukaya, Yukina Takagi, Asami Yokozawa
BACKGROUND: Although individuals with bilateral spastic cerebral palsy (BSCP) exhibit several deficits in anticipatory postural adjustments (APAs) while standing, effects of severity of motor disability on their APAs are unclear. AIMS: To determine whether individuals with BSCP exhibit severity-dependent deficits in APAs. METHODS AND PROCEDURES: Seven individuals with level II BSCP (BSCP-II group) and seven with level III BSCP (BSCP-III group) according to the Gross Motor Function Classification System and seven healthy controls lifted a load under two different load conditions...
October 2016: Research in Developmental Disabilities
Tatsunori Watanabe, Kazuto Ishida, Shigeo Tanabe, Ippei Nojima
A loud auditory stimulus (LAS) presented simultaneously with a visual imperative stimulus can reduce reaction time (RT) by automatically triggering a movement prepared in the brain and has been used to investigate a movement preparation. It is still under debate whether or not a response is prepared in advance in RT tasks involving choice responses. The purpose of the present study was to investigate the preparatory state of anticipatory postural adjustments (APAs) during a choice reaction step initiation. Thirteen young adults were asked to step forward in response to a visual imperative stimulus in two choice stepping conditions: (i) the responding side is not known and must be selected and (ii) the responding side is known but whether to initiate or inhibit a step response must be selected...
September 22, 2016: Neuroscience
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