Effects of multi-directional surface perturbations on the triggered postural responses in hemiplegic subjects during standing and walking
Bibliographic record
Abstract
Injury to the central nervous system as a result of cerebrovascular accidents (CVA) often leads to impairment in balance and mobility.Very little is known about the strategies that patients with CVA employ to prevent falls during unexpected changes of a support surface while patients are standing and walking.Previous studies showed that light touch increases postural stability in healthy subjects.However, it is not known whether patients with CVA would benefit from light touch in the same way as the healthy subjects do.Three studies in this research were conducted to examine the impact of stroke on postural responses triggered by surface rotations (Triggered Postural Responses; TPRs) during standing and walking and to investigate the effect of light touch on the control of TPRs during both tasks.Pitch and roll surface rotations (amplitude:5 o ; peak velocity:32 o /s) were randomly presented to 11 stroke and 8 healthy age-matched subjects during quiet stance and walking, with similar limb geometry in double limb support.Light touch (<4N) was provided by a load sensor strip mounted on a rail along the walkway.Body kinematics was captured at 120 Hz by a 6-camera Vicon 512 system.Ground reaction forces were acquired at 1080Hz by 2 AMTI force plates.Surface EMGs were recorded at 1080 Hz from 4 bilateral lower limb muscles.Results showed that TPRs in healthy subjects were functionally appropriate to the direction of perturbations and task demands, such that TPRs were tuned down during walking, as compared to standing, suggesting that postural requirements are less during walking.In contrast, CVA disrupts equilibrium control such that TPRs in the stroke subjects were delayed and not modulated as the perturbed directions and task demands changed, possibly due to problems in sensorimotor integration.Asymmetry was characterized by under-activated muscle responses and force generations of the paretic side and hyperactivity of the non-paretic upper and lower iv taient diminus pendant la marche comparativement la position debout, ce qui suggre que les exigences posturales sont moindres pendant la marche.Au contraire, la perturbation du contrle de l'quilibre et de l'intgration sensori-motrice chez les sujets ayant eu un AVC entrane un retard dans les APR de mme qu'une absence de modulation selon la tche et la direction de la rotation de la surface.Les membres infrieur et suprieur du ct partique ont montr une sous-activation des rponses musculaires et une diminution de force, alors qu'une sur-activation musculaire et une augmentation de force taient prsentes du ct non-partique.Ces modifications ont entran une instabilit du tronc et du centre de pression et ce, surtout dans le plan frontal.L'utilisation d'informations tactiles a amlior la stabilit posturale chez les sujets ayant survcu un AVC et, dans une moindre mesure, chez les sujets sains, ce qui suggre une utilit potentielle de cette technique pour la radaptation de l'quilibre.v
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".