https://www.sburover.it/psice/psicologia/valutazione_cognitiva/Postura.pdf

Attention and the control of posture and gait: a review of an emerging area of research

Falls in older people: risk factors and strategies for prevention.

Méthodes : Sur une série de 31 femmes présentant des varices périnéales d’origine extrasaphéniennes ayant bénéficié d’une exploration radiologique veineuse pelvienne et de l’embolisation des veines incontinentes nous avons étudié les résultats et les corrélations anatomo-clinique entre les varices et les signes cliniques de l’insuffisance veineuse pelvienne. Un sous-groupe B de 23 patientes présentant une insuffisance veineuse pelvienne et des signes cliniques a été comparé à un groupe A de 4 patientes qui ne présentaient pas d’insuffisance veineuse pelvienne à l’exploration. Nous avons choisi d’étudier 3 signes cliniques : la douleur pelvienne et la douleur des membres inférieurs survenant au début ou pendant les règles ainsi que la dyspareunie. La symptomatologie a été évaluée sur une échelle analogique de 0 à 10 et un score clinique (de 0 à 30) a été établi en ajoutant ces 3 chiffres.

http://link.springer.com/content/pdf/10.1007/BF02973687.pdf

Références bibliographiques: La fibroscopie bronchique

Background: the identification of specific risk factors for falls in community-dwelling elderly persons is required to identify older people at risk of falling. Objective: the aim of the study was to determine the ability of various biomechanical measures of postural stability to identify fallers in the elderly population. Method: 19 subjects (78.4 ± 1.3 years old) who reported having fallen unexpectedly at least twice in the last 6 months, and 124 non-fallers (77.8 ± 0.53 years old) participated in the study. Balance measurements were made in the upright position in six different conditions using a force platform, and the Limits of Stability Test was carried out. Static two-point discrimination (TPD) testing to the underside of the first toe was made to evaluate the innervation density of the slowly adapting receptors. Finally, maximal isometric lower limb strength was measured in major muscle groups. Repeated measures analysis of variance tests were performed to assess the mean differences between the two groups (fallers and non-fallers). The level of significance was set to 0.05. Results and discussion: results suggest that control of balance in narrow base stance may be an important tool in identifying elderly fallers. The findings show an increase in mediolateral sway in narrow base stance in older people who experienced recurrent falls. Also, TPD appears to be impaired in elderly fallers (14.93 ± 1.1 mm versus 12.98 ± 0.3 mm). Conclusions: simple and safe laboratory quantitative tests were able to differentiate between elderly fallers and elderly individuals who did not fall, suggesting a possible clinical application as a preliminary screening tool for predicting future risk of falling.

/pdf/postural-stability-in-the-elderly-a-comparison-between-duu2nkd3aw.pdf

Postural stability in the elderly: a comparison between fallers and non-fallers

This article reviews the evidence for cortical involvement in shaping postural responses evoked by external postural perturbations. Although responses to postural perturbations occur more quickly than the fastest voluntary movements, they have longer latencies than spinal stretch reflexes, suggesting greater potential for modification by the cortex. Postural responses include short, medium and long latency components of muscle activation with increasing involvement of the cerebral cortex as latencies increase. Evidence suggests that the cortex is also involved in changing postural responses with alterations in cognitive state, initial sensory-motor conditions, prior experience, and prior warning of a perturbation, all representing changes in "central set." Studies suggest that the cerebellar-cortical loop is responsible for adapting postural responses based on prior experience and the basal ganglia-cortical loop is responsible for pre-selecting and optimizing postural responses based on current context. Thus, the cerebral cortex likely influences longer latency postural responses both directly via corticospinal loops and shorter latency postural responses indirectly via communication with the brainstem centers that harbor the synergies for postural responses, thereby providing both speed and flexibility for pre-selecting and modifying environmentally appropriate responses to a loss of balance.

/pdf/cortical-control-of-postural-responses-55a0699gim.pdf

Cortical control of postural responses.

Background. One of the more pervasive effects of aging is loss of cutaneous sensation, which appears to correlate with im­ paired postural control and increased risk of falling. This study examined the potential for compensating for the destabilizing effects of reduced cutaneous sensitivity by placing a raised edge underneath the perimeter of the plantar foot surface, so as to facilitate sensation from the stability boundaries of the base of support. Methods.The main experiment involved 14 healthy older adults (aged 65-73) selected because they were known, from a previous study, to have moderate plantar cutaneous insensitivity. We also report results of an initial experiment involving 7 healthy young adults (aged 23-31). In both experiments, we studied effects of the plantar facilitation on control of rapid step­ ping reactions evoked by unpredictable postural perturbation, applied via sudden platform movement in forward, backward, and lateral directions. We also studied effects on "feet-in-place" responses evoked by continuous pseudorandom platform mo­ tion in mediolateral and anteroposterior directions. Subjects were blindfolded in all tests. Results.Plantar facilitation reduced the incidence of "extra" limb movements, beyond the initial step, during forward-step reactions in the older adults. There also appeared to be an improved ability to control feet-in-place reactions: young subjects were better able to recover balance without stepping when falling backward (given instructions to "try not to step"), and both young and older subjects reduced the extent to which the center of foot pressure approached the posterior foot boundary during continuous anteroposterior platform motion. Conclusions. This study provides evidence that mechanical facilitation of sensation from the boundaries of the plantar surface of the foot can improve the efficacy of certain types of stabilizing reactions evoked by unpredictable postural perturbation. The re­ sults may bedirectly transferable to the design of special footwear insoles to reduce instability and risk of falling in older adults.

/pdf/effect-of-facilitation-of-sensation-from-plantar-foot-15l9hb5b6h.pdf

Effect of Facilitation of Sensation From Plantar Foot-Surface Boundaries on Postural Stabilization in Young and Older Adults

The time course and extent of attentional shifts associated with compensatory balancing reactions were explored using a novel dual-task paradigm. Seated subjects performed a continuous visuomotor tracking task with the hand while the feet simultaneously balanced an inverted pendulum. The pendulum was randomly perturbed, evoking compensatory balance reactions. Changes in tracking performance were held to reflect attentional shifts. Discrete deviation in visuomotor tracking, typically a pause in tracking, began on average 235 ms after the onset of the balance reaction (TA EMG; average latency 90 ms). Such pauses lasted on average 600 ms, although additional errors in tracking lasted up to 9 s following the perturbation. The findings reveal evidence of dynamic shifts in attention associated with distinct phases of compensatory balance control. The initial phase appears to be triggered automatically, whereas later phases involve varying degrees of attentional resources.

Robert G. Norrie

Papers

Effect of Facilitation of Sensation From Plantar Foot-Surface Boundaries on Postural Stabilization in Young and Older Adults

Temporal properties of attention sharing consequent to disturbed balance.