11,086 research outputs found
Editorial: Gaze and postural stability rehabilitation
Proprioceptive, Visual, Vestibular, and Cognitive systems interact in a continuous sensorial re-weighting, ensuring gaze and postural control (1, 2). The central nervous system integrates the information originating from these systems into a continuous sensorial re-weighting that ensures postural control in both static and dynamic conditions (3, 4). The contribution of each sensory system changes depending on environmental conditions and the motor task performed by the person (5–7). To tailor a rehabilitative program for patients with gaze and postural stability disorders, a multidimensional assessment is required. A wide range of both clinical and instrumental evaluations could be performed before the rehabilitative approach in order to obtain quantitative and qualitative information about the patient's balance and gait disorders, supporting the rehabilitative staff in designing the most suitable therapeutic intervention. Instrumental assessment of the vestibular system has made significant progress in recent years. Two protocol tests are available in the clinical practice to evaluate the Vestibular Ocular Reflex (VOR) function through the use of Video Head Impulse Test (vHIT): Head Impulse Paradigm (HIMP) and Suppression Head Impulse Paradigm (SHIMP) (8–10). The head turn stimulus and the eye movement recording are identical. All that is changed are the instructions—from “look at that fixed target on the wall” to “look at the moving target.” At the same time, vestibular-evoked myogenic potentials are the most suitable test to evaluate otolith functions in patients with unilateral vestibular hypofunction in the acute and sub-acute phase
The development of the enterprising motivation in tourism students. A comparative analysis between grade and postgraduate students
Increasing the number of entrepreneurs and the quality of the entrepreneurship, it is the key thing because its positive influences over the economic activity. For this reason, it turns out essential to understand the factors that determine this phenomenon. This paper develops a model that includes those factors which allows acting on the enterprising intention of the students in the field of tourism. It has been decided on a theoretical approach based on the basics of the intentional theory from a perspective of higher education. A survey with a sample of 122 tourism students has been used ? including both graduates and students. Our analysis suggests that curricular and extracurricular activities have a different effect in the intentions, attitudes and capacities for the business? project development. On the other hand, our results show a weak impact of these activities in the business? competences
Water loss in horticultural products. Modelling, data analysis and theoretical considerations
The water loss of individual fruit (melon, plum and mandarin) was analysed using the traditional diffusion based approach and a kinetic approach. Applying simple non linear regression, both approaches are the same, resulting in a quite acceptable analysis. However, by applying mixed effects non linear regression analysis, explicitly including the variation over the individuals, the kinetic approach was found to reflect the processes occurring during mass loss better than the diffusion approach. All the variation between the individuals in a batch could be attributed to the initial mass or size of the individuals. The fraction of the fruit mass that is available for transpiration is the key item in the water loss process, rather than the skin resistance and fruit area. Obtained explained parts are well over 99%
Temblor ortostático como causa de inestabilidad
Orthostatic tremor (OT) is a neurological disease of unknown aetiology. It is defined
by the presence of a 10-20 Hz tremor in the legs while standing still. Symptoms described are
dizziness and instability that diminish if the patient sits down or leans on something; drinking
small amounts of alcohol significantly reduces OT. Due to the dizziness and/or unsteadiness,
these patients are usually referred to the neuro-otology department. We report 4 cases diagnosed
with OT. The diagnosis of OT should be considered for patients with instability. The
clinical history is a key factor to suspect this entity, and the diagnosis is given by the register of
10-20 Hz contractions on limb electromyography. Treatment for this disease consists of medical
treatment; the first option is clonazepam.
© 2011 Elsevier España, S.L. All rights reserved
Exploración posturográfica de pacientes simuladores
Introduction: An aphysiological pattern in computerized
dynamic posturography (CDP) may be produced by numerous
causes. We analyze the results obtained in this test
by a group of malingering patients.
Patients and method: This study analyzes a particular
group of 7 malingerers, ie patients simulating a false and
unreal equilibrium disorder, without any a priori awareness
of the gain expected from a pathological report. The condition
can only be identified with the very complex postural
disorder known as “continuous imbalance.” We analyze the
results of the dynamic posturography test following the
diagnostic criteria described by other authors.
Results: Of the criteria analyzed, we found Cevette’s to be
the most frequently positive for our study group.
Conclusions: The wide diversity in the criteria used makes
it necessary to apply them together, assuming a high level
of suspicion and great care in the diagnostic process
Resultados de los potenciales evocados miogĂ©nicos vestibulares en el vĂ©rtigo posicional paroxĂstico benigno
Objective: Benign paroxysmal positional vertigo (BPPV)
seems to occur because of otoconia migration into the semicircular
canals or their adherence to the cupula. Although
the origin of these otoconia lies in the macula of the utricle,
vestibular evoked myogenic potentials (VEMPs) can be
used assess saccular function. The aim of this study is to assess
the saccular function in patients diagnosed with BPPV.
Patients and method: Nineteen patients diagnosed with
BPPV of the posterior semicircular canal were included in
this study. Their auditory function and their caloric, rotatory
chair, and VEMP responses were tested. Ipsilateral and
contralateral VEMP thresholds, ipsilateral and contralateral
p13 and n23 latencies at 100 dB, inter-peak amplitude and
the interaural amplitude difference were determined.
Results: We found a lack of VEMP response in 52 % of the
ears with BPPV. When adjusted for bilateral absence, VEMP
response was absent in 20.3 % of ears.
Conclusions: Some patients with idiopathic BPPV show a
degree of saccular dysfunction
Design of arbitrary optical filters in silicon-on-insulator using evanescently-coupled Bragg gratings
Spectral filters are experiencing an increasing demand in several applications of the silicon-
on-insulator (SOI) platform. Many works have demonstrated that arbitrary frequency
responses can be synthesized by apodizing the coupling coefficient profile of an integrated
Bragg grating. However, the high index contrast of the SOI platform hinders their
practical implementation, due to the difficulty of achieving the precise control required in
the Bragg strength. In this paper, we propose the implementation of spectral filters using
an architecture based on placing loading segments within the evanescent field region of a
photonic wire waveguide. The Bragg coupling coefficient can be accurately controlled by
simply moving the segments away from, or closer to, the waveguide core. The layerpeeling
algorithm, in conjunction with a Floquet-Bloch modal analysis, allows to determine
the spatial distribution of the segments that synthesizes the desired spectrum. The
proposed topology is verified by designing a filter with five arbitrary passbands.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Histopathological reaction in the vestibule after cochlear implantation in Macaca fascicularis.
Cochlear implantation surgery (CI) is considered a safe procedure and is the standard treatment for the auditory
rehabilitation in patients with severe-to-profound sensorineural hearing loss. Although the development of
minimally traumatic surgical concepts (MTSC) have enabled the preservation of residual hearing after the implantation, there is scarce literature regarding the vestibular affection following MTCS.
The aim of the study is to analyze histopathologic changes in the vestibule after CI in an animal model (Macaca
fascicularis). Cochlear implantation was performed successfully in 14 ears following MTCS. They were classified
in two groups upon type of electrode array used. Group A (n = 6) with a FLEX 28 electrode array and Group B (n
= 8) with HL14 array. A 6-month follow-up was carried out with periodic objective auditory testing. After their
sacrifice, histological processing and subsequent analysis was carried out. Intracochlear findings, vestibular
presence of fibrosis, obliteration or collapse is analyzed. Saccule and utricle dimensions and neuroepithelium
width is measured.
Cochlear implantation was performed successfully in all 14 ears through a round window approach. Mean
angle of insertion was >270◦ for group A and 180–270◦ for group B. In group A auditory deterioration was
observed in Mf 1A, Mf2A and Mf5A with histopathological signs of scala tympani ossification, saccule collapse
(Mf1A and Mf2A) and cochlear aqueduct obliteration (Mf5A). Besides, signs of endolymphatic sinus dilatation
was seen for Mf2B and Mf5A. Regarding group B, no auditory deterioration was observed. Histopathological
signs of endolymphatic sinus dilatation were seen in Mf 2B and Mf 8B.
In conclusion, the risk of histological damage of the vestibular organs following minimally traumatic surgical
concepts and the soft surgery principles is very low. CI surgery is a safe procedure and it can be done preserving
the vestibular structures
The physics potential of a reactor neutrino experiment with Skipper CCDs: Measuring the weak mixing angle
We analyze in detail the physics potential of an experiment like the one
recently proposed by the vIOLETA collaboration: a kilogram-scale Skipper CCD
detector deployed 12 meters away from a commercial nuclear reactor core. This
experiment would be able to detect coherent elastic neutrino nucleus scattering
from reactor neutrinos, capitalizing on the exceptionally low ionization energy
threshold of Skipper CCDs. To estimate the physics reach, we elect the
measurement of the weak mixing angle as a case study. We choose a realistic
benchmark experimental setup and perform variations on this benchmark to
understand the role of quenching factor and its systematic
uncertainties,background rate and spectral shape, total exposure, and reactor
antineutrino flux uncertainty. We take full advantage of the reactor flux
measurement of the Daya Bay collaboration to perform a data driven analysis
which is, up to a certain extent, independent of the theoretical uncertainties
on the reactor antineutrino flux. We show that, under reasonable assumptions,
this experimental setup may provide a competitive measurement of the weak
mixing angle at few MeV scale with neutrino-nucleus scattering.Comment: 11 pages, 6 figure
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