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Millor Muruzábal, Nora

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https://academica-e.unavarra.es/handle/2454/49583

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Millor Muruzábal

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Nora

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Estadística, Informática y Matemáticas

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0000-0002-9037-4983

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9761

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2013 - 20192
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Subject: 30-s chair stand test ×

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Now showing 1 - 2 of 2
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    PublicationOpen 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 Gobernua
    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 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.
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    PublicationOpen 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 Ingeniaritzaren
    We 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.