126 research outputs found
Postural destabilization induced by trunk extensor muscles fatigue is suppressed by use of a plantar pressure-based electro-tactile biofeedback
Separate studies have reported that postural control during quiet standing
could be (1) impaired with muscle fatigue localized at the lower back, and (2)
improved through the use of plantar pressure-based electro-tactile biofeedback,
under normal neuromuscular state. The aim of this experiment was to investigate
whether this biofeedback could reduce postural destabilization induced by trunk
extensor muscles. Ten healthy adults were asked to stand as immobile as
possible in four experimental conditions: (1) no fatigue/no biofeedback, (2) no
fatigue/biofeedback, (3) fatigue/no biofeedback and (4) fatigue/biofeedback.
Muscular fatigue was achieved by performing trunk repetitive extensions until
maximal exhaustion. The underlying principle of the biofeedback consisted of
providing supplementary information related to foot sole pressure distribution
through electro-tactile stimulation of the tongue. Centre of foot pressure
(CoP) displacements were recorded using a force platform. Results showed (1)
increased CoP displacements along the antero-posterior axis in the fatigue than
no fatigue condition in the absence of biofeedback and (2) no significant
difference between the no fatigue and fatigue conditions in the presence of
biofeedback. This suggests that subjects were able to efficiently integrate an
artificial plantar pressure information delivered through electro-tactile
stimulation of the tongue that allowed them to suppress the destabilizing
effect induced by trunk extensor muscles fatigue
A Plantar-pressure Based Tongue-placed Tactile Biofeedback System for Balance Improvement
Maintaining an upright stance represents a complex task, which is achieved by
integrating sensory information from the visual, vestibular and somatosensory
systems. When one of these sensory inputs becomes unavailable and/or inaccurate
and/or unreliable, postural control generally is degraded. One way to solve
this problem is to supplement and/or substitute limited/altered/missing sensory
information by providing additional sensory information to the central nervous
system via an alternative sensory modality. Along these lines, we developed an
original biofeedback system [1] whose underlying principle consists in
supplying the user with supplementary sensory information related to foot sole
pressure distribution through a tongue-placed output device (Tongue Display
Unit, "TDU" [2]). The purpose of the present experiment was to assess its
effectiveness in improving balance in young healthy adults
Effets d'une suppl\'eance perceptive visuelle, auditive et tactile sur le contr\^ole des pressions fessi\`eres en position assise
This article presents a study on different informative modalities of a
perceptual supplementation device aiming at reducing overpressure at the
buttock area. Visual, audio and tactile modalities are analysed and compared
with a non-biofeedback session. In conclusion, modalities have a positive and
equal effect, but they are not equally judged in term of comfort and
disturbance with some other activitie
Using contextual factors to elicit placebo and nocebo effects: An online survey of healthcare providers' practice
Contextual factor use by healthcare professionals has been studied mainly among nurses and physiotherapists. Preliminary results show that healthcare professionals use contextual factors without specifically labelling them as such. The main objective of this study was to evaluate knowledge and explore voluntary contextual factor use among various healthcare professions. The results aim to facilitate hypothesis-generation, to better position further research to explain and characterise contextual factor use. We conducted a web-based questionnaire cross-sectional observational study on a non-probabilistic convenience sample. Face and content validity were tested through cognitive interviews. Data were analysed descriptively. The target population was the main healthcare profession, or final year students, defined by the French public health law. The countries of distribution of the questionnaire were the French-speaking European countries. Among our 1236 participants, use of contextual factors was widespread. Those relating to the therapeutic relationship (e.g., communication) and patient characteristics (e.g., past experiences) were reportedly the most used. Meanwhile, contextual factors related to the healthcare providers' characteristics and their own beliefs were reported as less used. Despite high variability, respondents suggested contextual effects contribute to approximately half of the overall effect in healthcare and were perceived as more effective on children and elderly adults. Conceptual variations that exist in the literature are also present in the way healthcare providers consider contextual effects. Interestingly, there seems to be common ground between how physiotherapists, nurses and physicians use different contextual factors. Finally, in the present study we also observed that while there are similarities across usage, there is lack of both an epistemological and ethical consensus among healthcare providers with respect to contextual factors
How a plantar pressure-based, tongue-placed tactile biofeedback modifies postural control mechanisms during quiet standing
The purpose of the present study was to determine the effects of a plantar
pressure-based, tongue-placed tactile biofeedback on postural control
mechanisms during quiet standing. To this aim, sixteen young healthy adults
were asked to stand as immobile as possible with their eyes closed in two
conditions of No-biofeedback and Biofeedback. Centre of foot pressure (CoP)
displacements, recorded using a force platform, were used to compute the
horizontal displacements of the vertical projection the centre of gravity
(CoGh) and those of the difference between the CoP and the vertical projection
of the CoG (CoP-CoGv). Altogether, the present findings suggest that the main
way the plantar pressure-based, tongue-placed tactile biofeedback improves
postural control during quiet standing is via both a reduction of the
correction thresholds and an increased efficiency of the corrective mechanism
involving the CoGh displacements
Sensory supplementation system based on electrotactile tongue biofeedback of head position for balance control
The present study aimed at investigating the effects of an artificial head
position-based tongue-placed electrotactile biofeedback on postural control
during quiet standing under different somatosensory conditions from the support
surface. Eight young healthy adults were asked to stand as immobile as possible
with their eyes closed on two Firm and Foam support surface conditions executed
in two conditions of No-biofeedback and Biofeedback. In the Foam condition, a
6-cm thick foam support surface was placed under the subjects' feet to alter
the quality and/or quantity of somatosensory information at the plantar sole
and the ankle. The underlying principle of the biofeedback consisted of
providing supplementary information about the head orientation with respect to
gravitational vertical through electrical stimulation of the tongue. Centre of
foot pressure (CoP) displacements were recorded using a force platform. Larger
CoP displacements were observed in the Foam than Firm conditions in the two
conditions of No-biofeedback and Biofeedback. Interestingly, this destabilizing
effect was less accentuated in the Biofeedback than No-biofeedback condition.
In accordance with the sensory re-weighting hypothesis for balance control, the
present findings evidence that the availability of the central nervous system
to integrate an artificial head orientation information delivered through
electrical stimulation of the tongue to limit the postural perturbation induced
by alteration of somatosensory input from the support surface
Re-weighting of somatosensory inputs from the foot and the ankle for controlling posture during quiet standing following trunk extensor muscles fatigue
The present study focused on the effects of trunk extensor muscles fatigue on
postural control during quiet standing under different somatosensory conditions
from the foot and the ankle. With this aim, 20 young healthy adults were asked
to stand as immobile as possible in two conditions of No fatigue and Fatigue of
trunk extensor muscles. In Experiment 1 (n = 10), somatosensation from the foot
and the ankle was degraded by standing on a foam surface. In Experiment 2 (n =
10), somatosensation from the foot and ankle was facilitated through the
increased cutaneous feedback at the foot and ankle provided by strips of
athletic tape applied across both ankle joints. The centre of foot pressure
displacements (CoP) were recorded using a force platform. The results showed
that (1) trunk extensor muscles fatigue increased CoP displacements under
normal somatosensatory conditions (Experiment 1 and Experiment 2), (2) this
destabilizing effect was exacerbated when somatosensation from the foot and the
ankle was degraded (Experiment 1), and (3) this destabilizing effect was
mitigated when somatosensation from the foot and the ankle was facilitated
(Experiment 2). Altogether, the present findings evidenced re-weighting of
sensory cues for controlling posture during quiet standing following trunk
extensor muscles fatigue by increasing the reliance on the somatosensory inputs
from the foot and the ankle. This could have implications in clinical and
rehabilitative areas
Postural control during quiet standing following cervical muscular fatigue: effects of changes in sensory inputs
The purpose of the present experiment was to investigate the effects of
cervical muscular fatigue on postural control during quiet standing under
different conditions of reliability and/or availability of somatosensory inputs
from the plantar soles and the ankles and visual information. To this aim, 14
young healthy adults were asked to sway as little as possible in three sensory
conditions (No vision, No vision-Foam support and Vision) executed in two
conditions of No fatigue and Fatigue of the scapula elevator muscles. Centre of
foot pressure (CoP) displacements were recorded using a force platform. Results
showed that (1) the cervical muscular fatigue yielded increased CoP
displacements in the absence of vision, (2) this effect was more accentuated
when somatosensation was degraded by standing on a foam surface and (3) the
availability of vision allowed the individuals to suppress this destabilising
effect. On the whole, these findings not only stress the importance of intact
cervical neuromuscular function on postural control during quiet standing, but
also suggest a reweigthing of sensory cues in balance control following
cervical muscular fatigue by increasing the reliance on the somatosensory
inputs from the plantar soles and the ankles and visual information
Differential postural effects of plantar-flexor muscles fatigue under normal, altered and improved vestibular and neck somatosensory conditions
The aim of the present study was to assess the effects of plantar-flexor
muscles fatigue on postural control during quiet standing under normal, altered
and improved vestibular and neck somatosensory conditions. To address this
objective, young male university students were asked to stand upright as still
as possible with their eyes closed in two conditions of No Fatigue and Fatigue
of the plantar-flexor muscles. In Experiment 1 (n=15), the postural task was
executed in two Neutral head and Head tilted backward postures, recognized to
degrade vestibular and neck somatosensory information. In Experiment 2 (n=15),
the postural task was executed in two conditions of No tactile and Tactile
stimulation of the neck provided by the application of strips of adhesive
bandage to the skin over and around the neck. Centre of foot pressure
displacements were recorded using a force platform. Results showed that (1) the
Fatigue condition yielded increased CoP displacements relative to the No
Fatigue condition (Experiment 1 and Experiment 2), (2) this destabilizing
effect was more accentuated in the Head tilted backward posture than Neutral
head posture (Experiment 1) and (3) this destabilizing effect was less
accentuated in the condition of Tactile stimulation than that of No tactile
stimulation of the neck (Experiment 2). In the context of the multisensory
control of balance, these results suggest an increased reliance on vestibular
and neck somatosensory information for controlling posture during quiet
standing in condition of altered ankle neuromuscular function
Inter-individual variability in sensory weighting of a plantar pressure-based, tongue-placed tactile biofeedback for controlling posture
The purpose of the present experiment was to investigate whether the sensory
weighting of a plantar pressure-based, tongue-placed tactile biofeedback for
controlling posture could be subject to inter-individual variability. To
achieve this goal, 60 young healthy adults were asked to stand as immobile as
possible with their eyes closed in two conditions of No-biofeedback and
Biofeedback. Centre of foot pressure (CoP) displacements were recorded using a
force platform. Overall, results showed reduced CoP displacements in the
Biofeedback relative to the No-biofeedback condition, evidencing the ability of
the central nervous system to efficiently integrate an artificial
plantar-based, tongue-placed tactile biofeedback for controlling posture during
quiet standing. Results further showed a significant positive correlation
between the CoP displacements measured in the No-biofeedback condition and the
decrease in the CoP displacements induced by the use of the biofeedback. In
other words, the degree of postural stabilization appeared to depend on each
subject's balance control capabilities, the biofeedback yielding a greater
stabilizing effect in subjects exhibiting the largest CoP displacements when
standing in the No-biofeedback condition. On the whole, by evidencing a
significant inter-individual variability in sensory weighting of an additional
tactile information related to foot sole pressure distribution for controlling
posture, the present findings underscore the need and the necessity to address
the issue of inter-individual variability in the field of neuroscience
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