31 research outputs found
Computation of Greatest Common Divisor for the Blind Deconvolution of Transient Impulsive Signals
Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip arthroplasty patients
The main goal of this study was to investigate how mobility characteristics during walking, relate to gait velocity and questionnaire outcomes of patients with hip osteoarthritis in an outpatient setting. Methods 22 patients with primary osteoarthritis of the hip selected for a total hip arthroplasty participated in this study. For each patient the Harris Hip Score, the Traditional Western Ontario and the McMaster Universities osteoarthritis index were administered. Subsequently, the patients were instructed to walk through the corridor while wearing instrumented shoes. The gait velocity estimated with the instrumented force shoes was validated measuring the time required to walk a distance of 10 m using a stopwatch and a measuring tape as a reference system. A regression analysis between spatial, temporal, ground reaction force parameters, including asymmetry, and the gait velocity and the questionnaires outcomes was performed
An evaluation of the 30-s chair stand test in older adults: frailty detection based on kinematic parameters from a single inertial unit
Background: A growing interest in frailty syndrome exists because it is regarded as a major predictor of
co-morbidities and mortality in older populations. Nevertheless, frailty assessment has been controversial,
particularly when identifying this syndrome in a community setting. Performance tests such as the 30-second chair
stand test (30-s CST) are a cornerstone for detecting early declines in functional independence. Additionally, recent
advances in body-fixed sensors have enhanced the sensorsâ ability to automatically and accurately evaluate
kinematic parameters related to a specific movement performance. The purpose of this study is to use this new
technology to obtain kinematic parameters that can identify frailty in an aged population through the performance
the 30-s CST.
Methods: Eighteen adults with a mean age of 54 years, as well as sixteen pre-frail and thirteen frail patients with
mean ages of 78 and 85 years, respectively, performed the 30-s CST while threir trunk movements were measured
by a sensor-unit at vertebra L3. Sit-stand-sit cycles were determined using both acceleration and orientation
information to detect failed attempts. Movement-related phases (i.e. impulse, stand-up, and sit-down) were
differentiated based on seat off and seat on events. Finally, the kinematic parameters of the impulse, stand-up and
sit-down phases were obtained to identify potential differences across the three frailty groups.
Results: For the stand-up and sit-down phases, velocity peaks and âmodified impulseâ parameters clearly
differentiated subjects with different frailty levels (p < 0.001). The trunk orientation range during the impulse phase
was also able to classify a subject according to his frail syndrome (p < 0.001). Furthermore, these parameters derived
from the inertial units (IUs) are sensitive enough to detect frailty differences not registered by the number of
completed cycles which is the standard test outcome.
Conclusions: This study shows that IUs can enhance the information gained from tests currently used in clinical
practice, such as the 30-s CST. Parameters such as velocity peaks, impulse, and orientation range are able to
differentiate between adults and older populations with different frailty levels. This study indicates that early frailty
detection could be possible in clinical environments, and the subsequent interventions to correct these disabilities
could be prescribed before further degradation occurs.The authors are indebted to the Spanish Department of Health and Institute
Carlos III of the Government of Spain [Spanish Net on Aging and frailty;
(RETICEF)], Department of Health of the Government of Navarre and
Economy and Competitivity Department of the Government of Spain, for
financing this research with grants numbered RD12/0043/0022, 87/2010, and
DEP2011-24105 respectively
Computation of greatest common divisor for the blind deconvolution of transient impulsive signals
ComunicaciĂłn presentada al First Internacional Workshop on Marine technology. Villanova i La GeltrĂș (Barcelona), 2005.We propose a new blind deconvolution method for transient impulsive signals in a single input
â multiple output (SIMO) system. The method
exploits the data redundancy inherent to SIMO
multichannel systems to obtain an estimation
of the input signal. The method is built upon the
assumptions of finite-length signals and channel
diversity
Frailty assessment based on trunk kinematic parameters during walking
Background: Physical frailty has become the center of attention of basic, clinical and demographic research due to
its incidence level and gravity of adverse outcomes with age. Frailty syndrome is estimated to affect 20 % of the
population older than 75 years. Thus, one of the greatest current challenges in this field is to identify parameters
that can discriminate between vulnerable and robust subjects. Gait analysis has been widely used to predict frailty.
The aim of the present study was to investigate whether a collection of parameters extracted from the trunk
acceleration signals could provide additional accurate information about frailty syndrome.
Methods: A total of 718 subjects from an elderly population (319 males, 399 females; age: 75.4 ± 6.1 years, mass:
71.8 ± 12.4 kg, height: 158 ± 6 cm) volunteered to participate in this study. The subjects completed a 3-m walk test
at their own gait velocity. Kinematic data were acquired from a tri-axial inertial orientation tracker.
Findings: The spatio-temporal and frequency parameters measured in this study with an inertial sensor are related
to gait disorders and showed significant differences among groups (frail, pre-frail and robust). A selection of those
parameters improves frailty classification obtained to gait velocity, compared to classification model based on gait
velocity solely.
Interpretation: Gait parameters simultaneously used with gait velocity are able to provide useful information for a
more accurate frailty classification. Moreover, this technique could improve the early detection of pre-frail status,
allowing clinicians to perform measurements outside of a laboratory environment with the potential to prescribe a
treatment for reversing their physical decline.This work was supported in part by the Spanish Department of Health and
Institute Carlos III of the Government of Spain [Spanish Net on Aging and
frailty; (RETICEF)], and Economy and Competitivity Department of the
Government of Spain, under grants numbered RD12/043/0002, and
DEP2011-24105, respectively
Penetrance of Dilated Cardiomyopathy in Genotype-Positive Relatives
BACKGROUND Disease penetrance in genotype -positive (G+) relatives of families with dilated cardiomyopathy (DCM) and the characteristics associated with DCM onset in these individuals are unknown. OBJECTIVES This study sought to determine the penetrance of new DCM diagnosis in G+ relatives and to identify factors associated with DCM development. METHODS The authors evaluated 779 G+ patients (age 35.8 +/- 17.3 years; 459 [59%] females; 367 [47%] with variants in TTN ) without DCM followed at 25 Spanish centers. RESULTS After a median follow-up of 37.1 months (Q1 -Q3: 16.3-63.8 months), 85 individuals (10.9%) developed DCM (incidence rate of 2.9 per 100 person -years; 95% CI: 2.3-3.5 per 100 person -years). DCM penetrance and age at DCM onset was different according to underlying gene group (log -rank P = 0.015 and P <0.01, respectively). In a multivariable model excluding CMR parameters, independent predictors of DCM development were: older age (HR per 1 -year increase: 1.02; 95% CI: 1.0-1.04), an abnormal electrocardiogram (HR: 2.13; 95% CI: 1.38-3.29); presence of variants in motor sarcomeric genes (HR: 1.92; 95% CI: 1.05-3.50); lower left ventricular ejection fraction (HR per 1% increase: 0.86; 95% CI: 0.82-0.90) and larger left ventricular end -diastolic diameter (HR per 1 -mm increase: 1.10; 95% CI: 1.06-1.13). Multivariable analysis in individuals with cardiac magnetic resonance and late gadolinium enhancement assessment (n = 360, 45%) identi fied late gadolinium enhancement as an additional independent predictor of DCM development (HR: 2.52; 95% CI: 1.43-4.45). CONCLUSIONS Following a first negative screening, approximately 11% of G+ relatives developed DCM during a median follow-up of 3 years. Older age, an abnormal electrocardiogram, lower left ventricular ejection fraction, increased left ventricular end -diastolic diameter, motor sarcomeric genetic variants, and late gadolinium enhancement are associated with a higher risk of developing DCM. (J Am Coll Cardiol 2024;83:1640 -1651) (c) 2024 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)