Person: Gómez Fernández, Marisol
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Gómez Fernández
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Marisol
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Matemática e Informática
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0000-0003-3431-1256
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Publication Open Access Impacto en el personal sanitario de urgencias extrahospitalarias de las cargas elevadas en la movilización de pacientes con silla de transporte(Asociación de Especialistas en Enfermería del Trabajo, 2018) Arenal Gota, Tania; Viana Gárriz, Juan Luis; Millor Muruzábal, Nora; Martínez Ramírez, Alicia; Gómez Fernández, Marisol; Belzunegui Otano, Tomás; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Ciencias de la Salud; Osasun ZientziakIntroducción. El objetivo del estudio es valorar el esfuerzo físico realizado por el personal de la urgencia extrahospitalaria al trasladar pacientes de su domicilio a la ambulancia. Material y métodos. Estudio observacional transversal con un muestreo no probabilístico de conveniencia. Se comparan tres grupos: bomberos, mujeres y hombres técnicos en emergencias sanitarias (TES), utilizando sensores inerciales con los que obtenemos datos relativos del movimiento que ejecutan 10 profesionales sanitarios del ámbito extrahospitalario (4 bomberos y 6 TES) al bajar un paciente por las escaleras en condiciones similares a una urgencia. Resultados. Los sujetos que se encuentran en la posición de arriba en el desplazamiento de la carga presentan mayor aceleración en el plano suelo-techo y en la pierna izquierda. Las mujeres presentaron mayor aceleración en piernas y brazos que el resto, sin embargo, es en los brazos donde es significativamente superior. Cuando el sujeto que está en la posición de abajo en el desplazamiento de la carga, bajando la silla de espaldas, la aceleración de las piernas es superior que al bajarla en sentido de la marcha. Conclusiones. Los sujetos presentan mayor aceleración en piernas, siendo el lugar del cuerpo que sufre la suma del peso del paciente y del trabajador. Las mujeres presentan una mayor aceleración por lo que su esfuerzo físico es más acusado. Bajar la silla en sentido de la marcha, disminuye la aceleración en las piernas por lo que está posición es ergonómicamente mejor. Cuanto mayor es la estabilidad al bajar la silla y mayor seguridad del trabajador al desempeñar este trabajo, disminuye su aceleración y por lo tanto el esfuerzo físico que realiza.Publication Embargo Enhancing sensorimotor BCI performance with assistive afferent activity: an online evaluation(Elsevier, 2019) Vidaurre, Carmen; Ramos Murguialday, Ander; Haufe, Stefan; Gómez Fernández, Marisol; Müller, Klaus Robert; Nikulin, Vadim V.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta MatematikaAn important goal in Brain-Computer Interfacing (BCI) is tofind and enhance procedural strategies for users for whom BCI control is not sufficiently accurate. To address this challenge, we conducted offline analyses and online experiments to test whether the classification of different types of motor imagery could be improved when the training of the classifier was performed on the data obtained with the assistive muscular stimulation below the motor threshold. 10 healthy participants underwent three different types of experimental conditions: a) Motor imagery (MI) of hands and feet b) sensory threshold neuromuscular electrical stimulation (STM) of hands and feet while resting and c) sensory threshold neuromuscular electrical stimulation during performance of motor imagery (BOTH). Also, another group of 10 participants underwent conditions a) and c). Then, online experiments with 15 users were performed. These subjects received neurofeedback during MI using classifiers calibrated either on MIor BOTH data recorded in the same experiment. Offline analyses showed that decoding MI alone using a classifier based on BOTH resulted in a better BCI accuracy compared to using a classifier based on MI alone. Online experiments confirmed accuracy improvement of MI alone being decoded with the classifier trained on BOTH data. In addition, we observed that the performance in MI condition could be predicted on the basis of a more pronounced connectivity within sensorimotor areas in the frequency bands providing the best performance in BOTH. Thesefinding might offer a new avenue for training SMR-based BCI systems particularly for users having difficulties to achieve efficient BCI control. It might also be an alternative strategy for users who cannot perform real movements but still have remaining afferent pathways (e.g., ALS and stroke patients).Publication Embargo Canonical maximization of coherence: a novel tool for investigation of neuronal interactions between two datasets(Elsevier, 2019) Vidaurre, Carmen; Nolte, Guido; Vries, I. E. J. de; Gómez Fernández, Marisol; Boonstra, Tjeerd W.; Müller, Klaus Robert; Villringer, Arno; Nikulin, Vadim V.; Estadística, Informática y Matemáticas; Estatistika, Informatika eta MatematikaSynchronization between oscillatory signals is considered to be one of the main mechanisms through which neuronal populations interact with each other. It is conventionally studied with mass-bivariate measures utilizing either sensor-to-sensor or voxel-to-voxel signals. However, none of these approaches aims at maximizing syn-chronization, especially when two multichannel datasets are present. Examples include cortico-muscular coherence (CMC), cortico-subcortical interactions or hyperscanning (where electroencephalographic EEG/magnetoencephalographic MEG activity is recorded simultaneously from two or more subjects). For all of these cases, a method which could find two spatial projections maximizing the strength of synchronization would be desirable. Here we present such method for the maximization of coherence between two sets of EEG/MEG/EMG(electromyographic)/LFP (localfield potential) recordings. We refer to it as canonical Coherence (caCOH). caCOH maximizes the absolute value of the coherence between the two multivariate spaces in the frequency domain. Thisallows very fast optimization for many frequency bins. Apart from presenting details of the caCOH algorithm, we test its efficacy with simulations using realistic head modelling and focus on the application of caCOH to the detection of cortico-muscular coherence. For this, we used diverse multichannel EEG and EMG recordings and demonstrate the ability of caCOH to extract complex patterns of CMC distributed across spatial and frequency domains. Finally, we indicate other scenarios where caCOH can be used for the extraction of neuronal interactions.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 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.Publication Open Access Modeling of noisy acceleration signals from quasi-periodic movements for drift-free position estimation(IEEE, 2019) Zivanovic, M; Millor, N; Gomez, M; Gómez Fernández, Marisol; Millor Muruzábal, Nora; Zivanovic Jeremic, Miroslav; Estadística, Informática y Matemáticas; Ingeniería Eléctrica, Electrónica y de Comunicación; Estatistika, Informatika eta Matematika; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio IngeniaritzarenWe present a novel approach to drift-free position estimation from noisy acceleration signals which often arise from quasi-periodic small-amplitude body movements. In contrast to the existing methods, this data-driven strategy is designed to properly describe time-variant harmonic structures in single-channel acceleration signals for low signal-to-noise ratios. Methods: It comprises three processing steps: (1) shorttime modeling of acceleration dynamics (instantaneous harmonic amplitudes and phases) in the analysis frame, (2) analytical integration which yields short-time position, and (3) overlap-add recombination for full length position synthesis. Results: The comparative results, obtained from the medio-lateral Xacceleration components from 30s Chair Stand Test recordings, suggest that the proposed method outperforms two state-of-theart reference methods in terms of Euclidean error, root mean square error, correlation coefficient and harmonic-to-noise ratio. Conclusion: A major benefit of the method is that acceleration signal components unrelated to movement are suppressed in the whole analysis bandwidth, which allows for position estimation completely free of low-frequency artifacts. Significance: We believe that the method can be useful in frailty assessment in elderly population, as well as in clinical applications related to gait analysis in aging and rehabilitation.