Marisol Gómez

Universidad Pública de Navarra | UPNA · Department of Mathematics

Periodic signals called Steady-State Visual Evoked Potentials (SSVEP) are elicited in the brain by flickering stimuli. They are usually detected by means of regression techniques that need relatively long trial lengths to provide feedback and/or sufficient number of calibration trials to be reliably estimated in the context of brain-computer interf...

Objective: Motor imagery is the mental simulation of movements. It is acommon paradigm to design Brain-Computer Interfaces (BCI) that elicits the modulation of brain oscillatory activity similar to real, passive and induced movements. In this study, we used peripheral stimulation to provoke movements of one limb during the performance of motor ima...

Literature of brain-computer interfacing (BCI) for steady-state visual evoked potentials (SSVEP) shows that canonical correlation analysis (CCA) is the most used method to extract features. However, it is known that CCA tends to rapidly overfit, leading to a decrease in performance. Furthermore, CCA uses information of just one class, thus neglecti...

This contribution reports the development and characterization of an optical system based on parallel Fiber Bragg Gratings (FBGs) to monitor the movements of the wrist and fingers of a hand. The system consisted of a reflective configuration made of FBGs detecting the movements of the fingers and one more located on the wrist as a reference. All FB...

Frailty is an important concept in clinical and demographic research in the elderly because of its incidence level and its relationship with adverse outcomes. Functional ability declines with advanced age, likely due to changes in muscle function. This study aimed to examine the relationship between muscle quality and muscle power with kinematics f...

Background Motor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the extent to which MAs are related to alterations of subcortical structures remains understudied. Methods We aimed to investigate the associations of MAs and basal ganglia abnormalities in first-episode psychosis (FEP) and healthy controls. Magnetic res...

Approximately one-third of elderly people fall each year with severe consequences, including death. The aim of this study was to identify the most relevant features to be considered to maximize the accuracy of a logistic regression model designed for prediction of fall/mortality risk among older people. This study included 261 adults, aged over 65...

Synchronization 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 synchronization, especiall...

An important goal in Brain-Computer Interfacing (BCI) is to find 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...

Objective: 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 lo...

Revista Enfermería del Trabajo 2018; 8:1(53-61) Artículo Original 53 Impacto en el personal sanitario de urgencias extrahospitalarias de las cargas elevadas en la movilización de pacientes con silla de transporte ARTÍCULO ORIGINAL Impacto en el personal sanitario de urgencias extrahospitalarias de las cargas elevadas en la movilización de pacientes...

Frailty is characterized by a loss of functionality and is expected to affect 9.9% of people aged 65 and over. Here, current frailty classification is compared to a collection of selected kinematic parameters. A total of 718 elderly subjects (319 males and 399 females; age: 75.4 ± 6.1 years), volunteered to participate in this study and were classi...

Motor 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 abnorma...

Patients with first-episode psychosis (FEP) exhibit considerable heterogeneity in subcortical brain volumes. We sought to compare ventricle and basal ganglia volumes in FEP patients (n = 50) with those in unaffected relatives (n = 21) and healthy controls (n = 24). Participants were assessed with a semistructured interview and underwent structural...

In this paper, fuzzy finite transition systems and fuzzy transformation semigroups are analyzed when the truth structure is the set of all the closed real subintervals contained in . Our approach involves the application of interval-valued fuzzy sets techniques in order to retrieve the information given by the transition functions of the considered...

Objective: Myotonic dystrophy type 1 (DM1), the most prevalent inherited neuromuscular disease in adults, is a genetic multisystem disorder with a well-established but not well-characterized cerebral involvement. The aim of this study was to evaluate the presence of white matter and gray matter abnormalities in DM1 patients and to investigate thei...

Background and objectives: In this paper we propose a novel single-channel harmonic and baseline noise removal approach based on the low-rank matrix factorization theory. It aims to enhance spectrogram sparsity in order to significantly reduce the dimensionality of the underlying sources in the input data. Such a low-rank non-negative representati...

In this study, several products of fuzzy transformation semigroups are generalized to the case where their truth structure is a complete lattice. We show that the direct product of two such fuzzy transformation semigroups is again a fuzzy transformation semigroup if and only if the lattice is distributive. In addition, after extending the cascade p...

A quarter to a half of people over 85 years are estimated to be frail by 2050. There is an urge to tackle this syndrome to assess the risk for an elderly to become frail. Performance tests such as the 30-s chair stand test (30-s CST) are a cornerstone for detecting early decline. Predictions are based on the number of repetitions instead of how the...

Background: Several studies have stated that frailty is associated with cognitive impairment. Based on various studies, cognition impairment has been considered as a component of frailty. Other authors have shown that physical frailty is associated with low cognitive performance. Dual task gait tests are used as a strong predictor of falls in eithe...

Introduction Parkinsonian motor signs are the most frequent of the genuine motor abnormalities present in drug-naïve patients with schizophrenia, and are also present in patients with a first-episode of psychosis (FEP). Objective To study whether there are differences in basal ganglia volumes depending on the presence of Parkinsonism in FEP. Meth...

The objective of this study was to investigate dual-task costs in several elderly populations, including robust oldest old, frail oldest old with MCI, frail oldest old without MCI, and frail elderly with dementia. Sixty-four elderly men and women, categorized into frail without MCI (age: 93.4±3.2 years, n=20); frail with MCI (age: 92.4±4.2 years, n...

Background: Frailty has become the center of attention of basic, clinical and demographic research because of its incidence level and the gravity of adverse outcomes with age. Moreover, with advanced age, motor variability increases, particularly in gait. Muscle quality and muscle power seem to be closely associated with performance on functional t...

We present a novel approach to single-channel power line interference (PLI) and baseline wander (BW) removal from surface electromyograms (EMG). It is based on non-negative matrix factorization (NMF) using a priori knowledge about the interferences. It performs a linear decomposition of the input signal spectrogram into non-negative components, whi...

Progress in micro-electromechanical systems has turned inertial sensor units (IUs) into a suitable tool for vertical jumping evaluation. 9 men and 8 women were recruited for this study. Three types of Vertical jumping tests were evaluated in order to determine if the data provided by an inertial sensor unit placed at the lumbar spine could reliably...

Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after re...

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 discrim...

Latest advances in microelectromechanical systems have made inertial units (IUs) a powerful tool for human motion analysis. However, difficulties in handling their output signals must be overcome. The purpose of this study was to develop the novel “PB-algorithm” based on polynomial data fitting, splines interpolation, and the wavelet transform, one...

Clinicians commonly use questionnaires and tests based on daily life activities to evaluate physical function. However, the outcomes are usually more qualitative than quantitative and subtle differences are not detectable. In this review, we aim to assess the role of body motion sensors in physical performance evaluation, especially for the sit-to-...

Objective To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images. Material and methods In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed during su...

Objective: To design a novel ex-vivo acquisition technique to establish a common framework to validate different segmentation techniques for oncological PET images. To evaluate several automatic segmentation algorithms on this set of images. Material and methods: In 15 patients with cancer, ex-vivo PET studies of surgical specimens removed durin...

Frailty syndrome is regarded as a major predictor of co-morbidities and mortality in older populations. Performance test such as the 30-s chair stand one (30-s CST) are a cornerstone for detecting early decline. However, predictions are normally more qualitative than quantitative. Latest advances in body-fixed sensors lead us to a new dimension of...

The interest in ageing has been notably increased in the last decade because of the continue increment of life expectancy. Some of its consequences like imparity or frailty have become the center of attention of basic, clinic and poblational investigations due to the incidence level and gravity of the adverse outcomes derived from the age. It is es...

This randomized controlled trial examined the effects of multicomponent training on muscle power output, muscle mass, and muscle tissue attenuation; the risk of falls; and functional outcomes in frail nonagenarians. Twenty-four elderly (91.9 ± 4.1 years old) were randomized into intervention or control group. The intervention group performed a twic...

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) a...

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 corners...

This study examined the neuromuscular and functional performance differences between frail oldest old with and without mild cognitive impairment (MCI). In addition, the associations between functional capacities, muscle mass, strength, and power output of the leg muscles were also examined. Forty-three elderly men and women (91.9±4.1 years) were cl...

The aim of this study was to evaluate the inertial measures of the 30-s chair stand test using modern body-fixed motion sensors. Polynomial data fitting was used to correct the drift effect in the position estimation. Thereafter, the three most important test cycles phases (“impulse,” “stand up,” and “sit down”) were characterized and automatically...

This paper provides a generalization of known results about fuzzy finite state machines, fuzzy transformation semigroups and their relationship by broading the truth values domain from the interval [0,1] to a complete lattice endowed with a t-norm and a t-conorm. So, we deal with the concepts of L-fuzzy finite state machines and L-fuzzy transformat...

This paper provides a generalization of known results about fuzzy finite state machines, fuzzy transformation semigroups and their relationship by broading the truth values domain from the interval [0,1] to a complete lattice endowed with a t-norm and a t-conorm. So, we deal with the concepts of L-fuzzy finite state machines and L-fuzzy transformat...

Tumor volume delineation over positron emission tomography (PET) images is of great interest for proper diagnosis and therapy planning. However, standard segmentation techniques (manual or semi-automated) are operator dependent and time consuming while fully automated procedures are cumbersome or require complex mathematical development. The aim of...

A standard phenotype of frailty was independently associated with an increased risk of adverse outcomes including comorbidity, disability and with increased risks of subsequent falls and fractures. Postural control deficit measurement during quiet standing has been often used to assess balance and fall risk in elderly frail population. Real time hu...

In order to measure spatial resolution of a PET tomograph in clinical conditions, this study describes and validates a method based on the recovery coefficient, a factor required to compensate underestimation in measured radioactivity concentration for small structures. In a PET image, the recovery factors of radioactive spheres were measured and t...

Ankle sprains are one of the most common lower extremity injuries. Real time human motion tracking is an accurate, inexpensive and portable system to obtain kinematic and kinetic measurements. The purpose of this study was to discriminate between subjects with chronic ankle instability and subjects with stable ankles through inertial tracking techn...

Single-event impulsive signals abound in acoustic systems. They are characterized by a confinement of their energy in a short time interval, and they usually arise, intentional or unintentionally, from explosive acoustic sources. They can seldom be observed directly, as propagation and echoes superposition distort their original impulsive shape. Th...

The problem of finding the greatest common divisor (GCD) of univariate polynomials appears in many engineering fields. Despite its formulation is well-known, it is an ill-posed problem that entails numerous difficulties when the coefficients of the polynomials are not known with total accuracy, as, for example, when they come from measurement data....

Dentro de cualquier población de individuos mayores de 65 años, una proporción sustancial (entre el 6% y el 25%) sufre diferentes síntomas del síndrome de fragilidad. A pesar de la complejidad del termino fragilidad y de las imprecisiones en cuanto a su definición existe un consenso sobre sus síntomas y signos. Las personas que poseen este síndrome...

If we consider a population of free-living individuals, who are 65 years old and even older, a substantial proportion (in the range of 6% to 25%) suffers from many of the elements of the syndrome of frailty. Although the syndrome is complex and still lacks a standard definition, there is a growing consensus about its signs and symptoms. Patients wh...

This work deals with the generalized eigenvalue problem for nonsquare matrix pencils A - AB such that matrices A, B ∈ Mc (m × n) show a given structure. More precisely, we assume they result from removing the first row of some matrix G ∈ Mc((m+1) ,n) in the case of A, and its last row in the case of B. This structured generalized eigenvalue problem...

Transient impulsive signals concentrate their energy in a short time interval. Impact force signals show this behaviour and play an important role in the study in mechanical systems. Measuring impact forces directly is not always possible and much research has been done in the last decades to develop indirect measuring techniques, which address the...

We prove the following results. Let π be a set of prime numbers and G a finite π-soluble group. Consider U,V≤G and H∈Hall π (G) such that H∩V∈Hall π (V) and 1≠H∩U∈Hall π (U). Suppose also that H∩U is a Hall π-subgroup of some S-permutable subgroup of G. Then H∩U∩V∈Hall π (U∩V) and 〈H∩U,H∩V〉∈Hall π (〈U,V〉). Therefore, the set of all S-permutably emb...

EEG stimulus-related responses have been extensively studied to gain insight on the functional behavior of the brain. Traditionally, these responses have been considered as the result of the generation of low-amplitude evoked potentials (EP). When averaged, these low-amplitude potentials come up from the background and can be cleanly observed. Inde...

EEG stimulus-related responses have been for years one of the main tools in the study of the brain. Traditionally, these responses have been considered as the result of the generation of low-amplitude evoked potentials. When averaged, these low-amplitude potentials come up from the background EEG, and can be clearly observed. Recent studies, howeve...

Independent component analysis (ICA) is one of the techniques proposed to solve the blind source separation (BSS) problem. ICA has proven to be an efficient tool for artifact extraction and analysis of electroencephalographic (EEG) recordings. In this work ICA is used to look for independent components of somatosensory evoked potentials (SEPs). Res...

Neuronal currents in the brain produce external magnetic fields and scalp surface potentials that can be measured using magnetoencephalography (MEG) and electroencephalography (EEG), respectively. In the context of the localization of neuronal sources, the forward problem is to determinate the potentials and magnetic fields that result from primary...

In this paper we present some results for p-subnormal subgroups (concept introduced by KEGEL in [6]). These statements are analogous to some well-known results for subnormal subgroups, mainly due to Wielandt, and they hold in all p-soluble groups. Nevertheless, since the set of all p-subnormal subgroups of a group fails to be a lattice new argument...

O. Kegel, in 1962, introduced the concept of p-subnormal subgroups of a finite group as the subgroups whose intersections with all Sylow p-subgroups of the group are Sylow p-subgroups of the subgroup. The set of p-subnormal subgroup of a finite group is not a lattice in general. In this paper, the class of all finite groups in which all p-subnormal...