Person: Lecumberri Villamediana, Pablo
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Lecumberri Villamediana
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Pablo
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Matemática e Informática
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Publication Open Access Design of low-cost smart accelerometers(Universitat Politècnica de Catalunya, 2005) Carlosena García, Alfonso; López Martín, Antonio; Massarotto, Marco; Cruz Blas, Carlos Aristóteles de la; Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Pintor Borobia, Jesús María; Gárriz Sanz, Sergio; Ingeniería Eléctrica y Electrónica; Matemáticas; Ingeniería Mecánica, Energética y de Materiales; Ingeniaritza Elektrikoa eta Elektronikoa; Matematika; Mekanika, Energetika eta Materialen IngeniaritzaThe goal of this project is to design a low-cost smart accelerometer, making use of a piezoelectric element as basic sensing material, and adding a mixed-mode conditioning circuit.Publication Open Access Multichannel blind deconvolution of impulsive signals(2005) Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Carlosena García, Alfonso; Matemáticas; Ingeniería Eléctrica y Electrónica; Matematika; Ingeniaritza Elektrikoa eta ElektronikoaIn this communication, the problem of blind deconvolution of transient, impulsive signals in a multichannel environment is addressed. This kind of signals arise naturally, or are used as external excitation, in many mechanical and acoustical systems and can only be observed indirectly, after propagation through the medium. Blind deconvolution or identi cation methods published to date are not suitable for recovering these sources or the system response, as identi ability conditions are not met. We fully develop here a deterministic subspace method for the blind deconvolution in a multichannel environment which does not impose any restrictions on the excitation signals or on the impulse response of propagation channels, apart from nite length and channel diversity. The method is also extended to cope with signals in noisy environments.Publication Open Access An evaluation of the 30-s chair stand test in older adults: frailty detection based on kinematic parameters from a single inertial unit(BioMed Central, 2013) Millor Muruzábal, Nora; Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Martínez Ramírez, Alicia; Izquierdo Redín, Mikel; Matemáticas; Ciencias de la Salud; Matematika; Osasun Zientziak; Gobierno de Navarra / Nafarroako GobernuaBackground: 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 sensors’ 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 “modified impulse” 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.Publication Open Access Computation of greatest common divisor for the blind deconvolution of transient impulsive signals(Universitat Politècnica de Catalunya, 2005) Lecumberri Villamediana, Pablo; Gómez Fernández, Marisol; Carlosena García, Alfonso; Matemáticas; Ingeniería Eléctrica y Electrónica; Matematika; Ingeniaritza Elektrikoa eta ElektronikoaWe propose a new blind deconvolution method for transient impulsive signals in a single input – 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.Publication Open Access Motor abnormalities and cognitive impairment in first-episode psychosis patients, their unaffected siblings and healthy controls(Elsevier, 2018) Cuesta, Manuel J.; Moreno-Izco, Lucía; Ribeiro Fernández, María; López-Ilundain, José M.; Lecumberri Villamediana, Pablo; Cabada Giadás, Teresa; Lorente Omeñaca, Ruth; Sánchez Torres, Ana María; Gómez Fernández, Marisol; Peralta Martín, Víctor; Ciencias de la Salud; Osasun Zientziak; Matemáticas; MatematikaMotor abnormalities (MAs) may be already evidenced long before the beginning of illness and are highly prevalent in psychosis. However, the extent to which the whole range of MAs are related to cognitive impairment in psychosis remains understudied. This study aimed to examine comparatively the relationships between the whole range of motor abnormalities and cognitive impairments in the first-episode of psychosis (FEP), their unaffected siblings and healthy control subjects. Fifty FEP patients, 21 of their healthy siblings and 24 age- and sex matched healthy controls were included. Motor assessment included catatonic, extrapyramidal and neurological soft signs (NSS) by means of standardized instruments. An exhaustive neuropsychological battery was also performed to extract the 7 cognitive dimensions of MATRICS initiative. Higher scores on NSS but not on extrapyramidal and catatonic signs showed significant associations with worse cognitive performance in the three study groups. However, the pattern of associations regarding specific cognitive functions was different among the three groups. Moreover, extrapyramidal signs showed significant associations with cognitive impairment only in FEP patients but not in their unaffected siblings and healthy controls. Catatonic signs did not show any significant association with cognitive functioning in the three study groups. These findings add evidence to the associations between motor abnormalities, particularly NSS and extrapyramidal signs, and cognitive impairment in first-episode psychosis patients. In addition, our results suggest that the specific pattern of associations between MAs and cognitive functioning is different in FEP patients from those of the unaffected siblings and healthy subjects.Publication Open Access Frailty assessment based on trunk kinematic parameters during walking(BioMed Central, 2015) Martínez Ramírez, Alicia; Martinikorena Aranburu, Ion; Gómez Fernández, Marisol; Lecumberri Villamediana, Pablo; Millor Muruzábal, Nora; Rodríguez Mañas, Leocadio; García García, Francisco José; Izquierdo Redín, Mikel; Matemáticas; MatematikaBackground: 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.