Biomedical subjects

L Poupard

Publications and source records attributed to L Poupard.

3 recordsLinked to original sources

PubMed2002

Does respiration perturb body balance more in chronic low back pain subjects than in healthy subjects?

OBJECTIVE: To determine whether body balance is perturbed more in low back pain patients than in healthy subjects, under the concept of posturo-kinetic capacity. DESIGN: Comparison of posturographic and respiratory parameters between low back pain and healthy subjects. BACKGROUND: It has been demonstrated that respiratory movements constitute a perturbation to posture, compensated by movements of the spine and of the hips, and that low back pain is frequently associated with a loss of back mobility. METHOD: Ten low back pain patients and ten healthy subjects performed five posturographic tests under three different respiratory rate conditions: quiet breathing (spontaneous), slow breathing (0.1 Hz) and fast breathing (0.5 Hz). RESULTS: Intergroup comparison showed that the mean displacements of the center of pressure were greater for the low back pain group, especially along the antero-posterior axis, where respiratory perturbation is primarily exerted. Inter-condition comparison showed that in slow and fast breathing relatively to quiet breathing, the mean displacement of the center of pressure along the antero-posterior axis was significantly increased only for the low back pain group. CONCLUSION: According to the results, respiration presented a greater disturbing effect on body balance in low back pain subjects. RELEVANCE: This study provides information on the causes of the impaired body balance associated with chronic low back pain, which could be used to improve treatment strategy.

Adult↗

PubMed2001

Does body stability depend on postural chain mobility or stability area?

The purpose of this study was to examine whether postural stability depends only on the support base perimeter, that is the stability area, when body balance is perturbed by respiration. To this end, seven normal subjects were asked to breathe quietly, breathe deeply and to hold their breath (apnoea). They were asked to maintain a standing posture (Sta), and two sitting postures differing by the ischio femoral contact with the seat (Sit100 and Sit30). In other words, these three postures differed not only by the stability area, but also by pelvis mobility. The thoracic perimeter, displacement of the centre of pressure (CP) and iliac crest acceleration (Ah), taken as an index of pelvis mobility, of seven normal subjects were recorded. The results showed that the sway path (SP) was longer in seated subjects than in standing ones, and in Sit100 than in Sit30. The distance between the CP extreme positions (Delta Xp) varied in the opposite direction to SP. Iliac crests and thoracic displacements were shown to be in phase in Sit condition, and did not display any particular pattern in Sta. It was concluded that postural steadiness depends on the postural chain mobility in addition to stability area. As pelvis and lumbar column mobility are related, it is proposed that both contribute to postural chain mobility, owing to respiratory perturbation being compensated.

Abdomen↗

PubMed2001

Scaling behavior in beta-wave amplitude modulation and its relationship to alertness.

We performed an experimental study of beta waves occurring in human electroencephalographic signals obtained from six healthy subjects that were monitored during the performance of a task requiring attention to auditory signals. We use wavelet analysis to study whether the fluctuations in the modulation of the beta-wave amplitude related to an indirect measurement of alertness. We found that these fluctuations exhibit a power-law behavior. When the level of alertness dropped, the associated exponent was found to increase, reflecting the fact that long-range correlations grow rapidly within the system. We also studied the fluctuations of amplitude modulation for alpha and theta waves, for which we did not find a power-law behavior.

Acoustic Stimulation↗