9 research outputs found
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
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
Methods of pattern classification for the design of a NIRS-based brain computer interface.
Brain-Computer Interface (BCI) is a communication system that offers the
possibility to act upon the surrounding environment without using our nervous systems
efferent pathways. One of the most important parts of a BCI is the pattern classification system
which allows to translate mental activities into commands for an external device. This work
aims at providing new pattern classification methods for the development of a Brain Computer
Interface based on Near Infrared Spectroscopy. To do so, a thorough study of machine learning
techniques used for developing BCIs has been conducted
Methods of pattern classification for the design of a NIRS-based brain computer interface.
Brain-Computer Interface (BCI) is a communication system that offers the
possibility to act upon the surrounding environment without using our nervous systems
efferent pathways. One of the most important parts of a BCI is the pattern classification system
which allows to translate mental activities into commands for an external device. This work
aims at providing new pattern classification methods for the development of a Brain Computer
Interface based on Near Infrared Spectroscopy. To do so, a thorough study of machine learning
techniques used for developing BCIs has been conducted
A Wireless Embedded Tongue Tactile Biofeedback System for Balance Control
We describe the architecture of an original biofeedback system for balance
improvement for fall prevention and present results of a feasibility study. The
underlying principle of this biofeedback consists of providing supplementary
information related to foot sole pressure distribution through a wireless
embedded tongue-placed tactile output device. Twelve young healthy adults
voluntarily participated in this experiment. They were asked to stand as
immobile as possible with their eyes closed in two conditions of nobiofeedback
and biofeedback. Centre of foot pressure (CoP) displacements were recorded
using a force platform. Results showed reduced CoP displacements in the
biofeedback relative to the no-biofeedback condition. On the whole, the present
findings evidence the effectiveness of this system in improving postural
control on young healthy adults. Further investigations are needed to
strengthen the potential clinical value of this device.Comment: Pervasive and Mobile Computing (2008) in pres
Can a Plantar Pressure-Based Tongue-Placed Electrotactile Biofeedback Improve Postural Control Under Altered Vestibular and Neck Proprioceptive Conditions?
We investigated the effects of a plantar pressure-based tongue-placed
electrotactile biofeedback on postural control during quiet standing under
normal and altered vestibular and neck proprioceptive conditions. To achieve
this goal, fourteen young healthy adults were asked to stand upright as
immobile as possible with their eyes closed in two Neutral and Extended head
postures and two conditions of No-biofeedback and Biofeedback. The underlying
principle of the biofeedback consisted of providing supplementary information
related to foot sole pressure distribution through a wireless embedded
tongue-placed tactile output device. Centre of foot pressure (CoP)
displacements were recorded using a plantar pressure data acquisition system.
Results showed that (1) the Extended head posture yielded increased CoP
displacements relative to the Neutral head posture in the No-biofeedback
condition, with a greater effect along the anteroposterior than mediolateral
axis, whereas (2) no significant difference between the two Neutral and
Extended head postures was observed in the Biofeedback condition. The present
findings suggested that the availability of the plantar pressure-based
tongue-placed electrotactile biofeedback allowed the subjects to suppress the
destabilizing effect induced by the disruption of vestibular and neck
proprioceptive inputs associated with the head extended posture. These results
are discussed according to the sensory re-weighting hypothesis, whereby the
central nervous system would dynamically and selectively adjust the relative
contributions of sensory inputs (i.e., the sensory weights) to maintain upright
stance depending on the sensory contexts and the neuromuscular constraints
acting on the subject
Toward simple control for complex, autonomous robotic applications: combining discrete and rhythmic motor primitives
Vertebrates are able to quickly adapt to new environments in a very robust, seemingly effortless way. To explain both this adaptivity and robustness, a very promising perspective in neurosciences is the modular approach to movement generation: Movements results from combinations of a finite set of stable motor primitives organized at the spinal level. In this article we apply this concept of modular generation of movements to the control of robots with a high number of degrees of freedom, an issue that is challenging notably because planning complex, multidimensional trajectories in time-varying environments is a laborious and costly process. We thus propose to decrease the complexity of the planning phase through the use of a combination of discrete and rhythmic motor primitives, leading to the decoupling of the planning phase (i.e. the choice of behavior) and the actual trajectory generation. Such implementation eases the control of, and the switch between, different behaviors by reducing the dimensionality of the high-level commands. Moreover, since the motor primitives are generated by dynamical systems, the trajectories can be smoothly modulated, either by high-level commands to change the current behavior or by sensory feedback information to adapt to environmental constraints. In order to show the generality of our approach, we apply the framework to interactive drumming and infant crawling in a humanoid robot. These experiments illustrate the simplicity of the control architecture in terms of planning, the integration of different types of feedback (vision and contact) and the capacity of autonomously switching between different behaviors (crawling and simple reaching
Student Research Programs in U.S. Medical Schools and Institutions
The majority of medical educators agree that scientific education is critical to the development of physician-scientists. However, the proportion of physicians interested or engaged in research has been decreasing. To overcome this deficit of research oriented physicians, many medical schools in the United States have introduced scholarly concentration (SC) programs into their medical curricula since 2000. In contrast, Korea has very few medical schools with such programs. Research programs at American medical schools were surveyed and investigated in order to better design and develop SC programs appropriate for Korean medical schools. Information on SC programs was gathered by reviewing medical school web sites and related articles. The SC programs of Brown Alpert Medical School, University of Pittsburgh School of Medicine, Duke University School of Medicine, and Stanford University School of Medicine are discussed in depth. The characteristics of each program were organized into seven parts: program description, administrative structure, orientation, curricular content, mentors and mentoring, student evaluation, and challenges. For a successful SC program in Korea we must consider providing guaranteed time for SC programs with necessary modifications in the core medical curriculum, educating and training of mentors, providing orientation and motivating students to pursue research, developing curricula for SC programs, and evaluating the progress of SC projects.ope