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Papers by Pablo Lecumberri

Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip... more Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip arthroplasty patients

Journal of Biomechanics, 2020

High density muscle size and muscle power are associated with both gait and sit-to-stand kinemati... more High density muscle size and muscle power are associated with both gait and sit-to-stand kinematic parameters in frail nonagenarians,

Psychological Medicine, 2020

BackgroundMotor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the... more BackgroundMotor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the extent to which MAs are related to alterations of subcortical structures remains understudied.MethodsWe aimed to investigate the associations of MAs and basal ganglia abnormalities in first-episode psychosis (FEP) and healthy controls. Magnetic resonance imaging was performed on 48 right-handed FEP and 23 age-, gender-, handedness-, and educational attainment-matched controls, to obtain basal ganglia shape analysis, diffusion tensor imaging techniques (fractional anisotropy and mean diffusivity), and relaxometry (R2*) to estimate iron load. A comprehensive motor battery was applied including the assessment of parkinsonism, catatonic signs, and neurological soft signs (NSS). A fully automated model-based segmentation algorithm on 1.5T MRI anatomical images and accurate corregistration of diffusion and T2* volumes and R2* was used.ResultsFEP patients showed significant local atrophic chan...

Journal of biomechanics, Jan 3, 2018

Schizophrenia research, Jan 30, 2017

Motor abnormalities (MAs) may be already evidenced long before the beginning of illness and are h... more 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 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. Howe...

Scandinavian Journal of Medicine & Science in Sports, 2017

Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMU... more Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMUs) into a suitable tool for vertical jumping biomechanical evaluation. Thus, the presented study aimed to determine if appropriate reliability and agreement reports could also be obtained when analysing 20m sprint mechanics. Four bouts of 20 m sprints were evaluated to determine if the data provided by a MIMU placed at the lumbar spine could reliably assess sprint mechanics and to examine the validity of the MIMU sensor compared to force plate recordings. Maximal power (P0), force (F0) and velocity (V0), as well as other mechanical determinants of sprint performance associated with the Force-Velocity, Power-Velocity and Ratio of Forces-Velocity, such as applied horizontal force loss (S fv) and decrease in ratio of forces (D rf), were calculated and compared between instrumentations. Extremely large to very large correlation levels between MIMU sensor based sprint mechanics variables and force plate recordings were obtained (mean ± standard deviation, force plate vs. MIMU;

Psychiatry Research: Neuroimaging, 2017

Patients with first-episode psychosis (FEP) exhibit considerable heterogeneity in subcortical bra... more 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 magnetic resonance imaging (MRI). Patients had significantly larger left lateral, right lateral and third ventricle volumes than their siblings and larger third ventricle volumes than controls. Additionally, they showed a trend toward significance by having larger right caudate nuclei than controls. Moreover, FEP patients showed lower caudate and putamen laterality indexes (leftward shifts) than healthy controls but not regarding their siblings. Besides, negative dimension was directly associated with lateral and third ventricle volumes and positive dimension with thalamus and ventral diencephalon nuclei. Our findings added evidence to the associations between early enlargement of brain ventricles and negative symptoms, and between early enlargement of thalamic and ventral-diencephalon nuclei and positive symptoms. Moreover, the cumulative exposition to antipsychotics in FEP patients might be related to enlargement of certain subcortical structures, such as the right nucleus accumbens and third ventricle.

Journal of biomechanics, Jan 20, 2017

The present research aimed to describe an inertial unit (IU)-based sprint mechanics evaluation mo... more The present research aimed to describe an inertial unit (IU)-based sprint mechanics evaluation model for assessing players' readiness to return to competition after suffering a grade I hamstring injury. A professional male football player (age 19years; height 177cm; weight 70kg, midfielder, Spanish, 3° Division) with a grade 1 biceps femoris injury was evaluated at pre-season, at return to play after injury and at the end of the competitive season. Sprint mechanics were analyzed via the use of an inertial orientation tracker (Xsens Technologies B.V. Enschede, Netherlands) attached over the L3-L4 region of the subject's lumbar spine. Sprint mechanics such as horizontal components of ground reaction force were assessed in both legs during sprinting actions. Findings and interpretation: Both the coefficient of the horizontal force application (SFV) and the ratio of forces (DRF) applied at increasing velocity were decreased in the injured limb compared with the contralateral hea...

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, Nov 27, 2017

Frailty is characterized by a loss of functionality and is expected to affect 9.9% of people aged... more 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 classified according to Fried´s criteria. Both the 30-s chair stand test (CST) and the 3-m walking test were performed and a set of kinematic parameters were obtained from a single inertial unit. A decision tree analysis was used to: (1) identify the most relevant frailty-related parameters and (2) compare validity of this classification. We found that a selected set of parameters from the 30-s CST (i.e. range of movement, acceleration and power) were better at identifying frailty status than both the actual outcome of the test (i.e. cycles' number) and the normally used criteria (i.e. gait speed). For the pre-frail status, AUC improves from...

Computer methods and programs in biomedicine, 2017

In this paper we propose a novel single-channel harmonic and baseline noise removal approach base... more 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 representation approach admits efficient noise removal. The sparsity is improved by a modification of the time-frequency basis through the following signal processing steps: (1) spectrograms segmentation, (2) non-negative rank estimation, and (3) source grouping. The source waveforms are retrieved by means of non-negative matrix factorization and the overlap-add method. The proposed method was tested on real electrocardiogram and electromyogram signals for different analysis scenarios, against two state-of-the-art reference methods. Performance evaluation was carried out by means of the output signal-to-interference ratio. In the electrocardiogram analysis scenarios, for the inp...

Archives of Clinical Neuropsychology, 2017

Objective: Myotonic dystrophy type 1 (DM1), the most prevalent inherited neuromuscular disease in... more 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 their relationship with neurocognitive dysfunction. Methods: A total of 42 DM1 patients and 42 healthy controls were included in the study. Clinical, cognitive, and magnetic resonance imaging evaluations, including the use of structural and diffusion tensor imaging (DTI) techniques, were performed. White matter lesion (WML) load, volumetric analysis, and diffusivity changes were assessed and correlated with clinical and neuropsychological test findings. Results: WMLs were significantly more frequent in DM1 patients (p < .001), and anterior temporal lobe lesions were only found in the patient group. Global and regional cortical volume loss and corpus callosum atrophy were found. Diffuse white matter DTI abnormalities, including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were observed with sparing of the internal capsule. Subcortical structures showed volume loss and increased median diffusivity. Neuropsychological evaluation showed significant impairment in several cognitive functions, but only visuospatial impairment was correlated with white matter abnormalities and cortical atrophy. Daytime sleepiness was associated with WML and ventral diencephalon and pallidum volume loss. Conclusion: DM1 produces a widespread involvement of white matter and gray matter, including cortical and subcortical structures. These structural abnormalities are involved in the progressive neuropsychological functional impairment in these patients

Dementia and geriatric cognitive disorders, Jan 27, 2016

Several studies have stated that frailty is associated with cognitive impairment. Based on variou... more 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 either dementia or frailty. Consequently, it is important to investigate dual task walking tests in elderly populations including control robust oldest old, frail oldest old with mild cognitive impairment (MCI) and frail oldest old without MCI. Dual task walking tests were carried out to examine the association between frailty and cognitive impairment in a population with advanced age. Forty-one elderly men and women participated in this study. The subjects from control, frail with MCI and frail without MCI groups, completed the 5-meter walk test at their own gait velocity. Arithmetic and verbal dual task walking performance was also assessed. Kinematic da...

European Psychiatry, 2016

IntroductionParkinsonian motor signs are the most frequent of the genuine motor abnormalities pre... more IntroductionParkinsonian 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).ObjectiveTo study whether there are differences in basal ganglia volumes depending on the presence of Parkinsonism in FEP.MethodsForty-six patients with a FEP were included in the study. Twenty-three controls were included to normalise patients’ brain volume data. Parkinsonism was assessed with the UKU scale. Brain volumes were obtained with MRI (1.5 Tesla Siemens Avanto). Reconstruction and volumetric segmentation was made with the Freesurfer© software (http://surfer.nmr.mgh.harvard.edu/). Patients were divided into two groups, considering the presence/absence of Parkinsonism (UKU total score cutoff point = 4). Patients have been treated with antipsychotics a mean of less than 2 months. There were not significant differences in the total exposure to antipsychotics bet...

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

We present a novel approach to single-channel power line interference (PLI) and baseline wander (... more 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, which represent the PLI, BW and EMG spectrogram estimates. They all exhibit very different time-frequency patterns: PLI and BW are both sparse whereas EMG is noise-like. Initialization of the classical NMF algorithm with accurately designed PLI, BW and EMG structures and a carefully adjusted matrix decomposition rank increases the separation performance. The comparative study suggests that the proposed method outperforms two state-of-the-art reference methods.

Journal of the American Medical Directors Association, 2016

Frailty has become the center of attention of basic, clinical, and demographic research because o... more 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 tests in frail populations. Insight into the relationships among muscle power, muscle quality, and functional capacity could improve the quality of life in this population. In this study, the relationship between the quality of the muscle mass and muscle strength with gait performance in a frail population was examined. Twenty-two institutionalized frail elderly individuals (93.1 ± 3.6) participated in this study. Muscle quality was measured by segmenting areas of high- and low-density fibers as observed in computed tomography images. The assessed functional outcomes were leg strength and power, velocity of gait, and kinematic gait parameters obtained from a tri-axial inertial sensor. Our results showed that a greater number of high-density fibers, specifically those of the quadriceps femoris muscle, were associated with better gait performance in terms of step time variability, regularity, and symmetry. Additionally, gait variability was associated with muscle power. In contrast, no significant relationship was observed between gait velocity and either muscle quality or muscle power. Gait pattern disorders could be explained by a deterioration of the lower limb muscles. It is known that an impaired gait is an important predictor of falls in older populations; thus, the loss of muscle quality and power could underlie the impairments in motor control and balance that lead to falls and adverse outcomes.

Journal of NeuroEngineering and Rehabilitation, 2015

Background: Physical frailty has become the center of attention of basic, clinical and demographi... more 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.

Proceedings of the Second Joint 24th Annual Conference and the Annual Fall Meeting of the Biomedical Engineering Society] [Engineering in Medicine and Biology

Independent component analysis (ICA) is one of the techniques proposed to solve the blind source ... more 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). Results agree with the classical SEP source modeling theory.

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)

... Miguel Valencia'72, Manuel Alegre', Julio Artieda', Armando Malanda2, Pablo Le... more ... Miguel Valencia'72, Manuel Alegre', Julio Artieda', Armando Malanda2, Pablo Lecumberri3,Marisol G6mez3. ... N. Velis, FH Lopes da Silva, “Enhace-ment of phase clustering in the EEG/MEG gamma frequency band anticipates transitions to paroxysmal epileptiform activity in ...

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)

EEG stimulus-related responses have been extensively studied to gain insight on the functional be... more 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. Independent component analysis (ICA) is a technique widely used to solve

Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip... more Pre-operative ambulatory measurement of asymmetric lower limb loading during walking in total hip arthroplasty patients

Journal of Biomechanics, 2020

High density muscle size and muscle power are associated with both gait and sit-to-stand kinemati... more High density muscle size and muscle power are associated with both gait and sit-to-stand kinematic parameters in frail nonagenarians,

Psychological Medicine, 2020

BackgroundMotor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the... more BackgroundMotor abnormalities (MAs) are the primary manifestations of schizophrenia. However, the extent to which MAs are related to alterations of subcortical structures remains understudied.MethodsWe aimed to investigate the associations of MAs and basal ganglia abnormalities in first-episode psychosis (FEP) and healthy controls. Magnetic resonance imaging was performed on 48 right-handed FEP and 23 age-, gender-, handedness-, and educational attainment-matched controls, to obtain basal ganglia shape analysis, diffusion tensor imaging techniques (fractional anisotropy and mean diffusivity), and relaxometry (R2*) to estimate iron load. A comprehensive motor battery was applied including the assessment of parkinsonism, catatonic signs, and neurological soft signs (NSS). A fully automated model-based segmentation algorithm on 1.5T MRI anatomical images and accurate corregistration of diffusion and T2* volumes and R2* was used.ResultsFEP patients showed significant local atrophic chan...

Journal of biomechanics, Jan 3, 2018

Schizophrenia research, Jan 30, 2017

Motor abnormalities (MAs) may be already evidenced long before the beginning of illness and are h... more 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 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. Howe...

Scandinavian Journal of Medicine & Science in Sports, 2017

Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMU... more Advances in micro-electromechanical systems have turned magnetic inertial measurement units (MIMUs) into a suitable tool for vertical jumping biomechanical evaluation. Thus, the presented study aimed to determine if appropriate reliability and agreement reports could also be obtained when analysing 20m sprint mechanics. Four bouts of 20 m sprints were evaluated to determine if the data provided by a MIMU placed at the lumbar spine could reliably assess sprint mechanics and to examine the validity of the MIMU sensor compared to force plate recordings. Maximal power (P0), force (F0) and velocity (V0), as well as other mechanical determinants of sprint performance associated with the Force-Velocity, Power-Velocity and Ratio of Forces-Velocity, such as applied horizontal force loss (S fv) and decrease in ratio of forces (D rf), were calculated and compared between instrumentations. Extremely large to very large correlation levels between MIMU sensor based sprint mechanics variables and force plate recordings were obtained (mean ± standard deviation, force plate vs. MIMU;

Psychiatry Research: Neuroimaging, 2017

Patients with first-episode psychosis (FEP) exhibit considerable heterogeneity in subcortical bra... more 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 magnetic resonance imaging (MRI). Patients had significantly larger left lateral, right lateral and third ventricle volumes than their siblings and larger third ventricle volumes than controls. Additionally, they showed a trend toward significance by having larger right caudate nuclei than controls. Moreover, FEP patients showed lower caudate and putamen laterality indexes (leftward shifts) than healthy controls but not regarding their siblings. Besides, negative dimension was directly associated with lateral and third ventricle volumes and positive dimension with thalamus and ventral diencephalon nuclei. Our findings added evidence to the associations between early enlargement of brain ventricles and negative symptoms, and between early enlargement of thalamic and ventral-diencephalon nuclei and positive symptoms. Moreover, the cumulative exposition to antipsychotics in FEP patients might be related to enlargement of certain subcortical structures, such as the right nucleus accumbens and third ventricle.

Journal of biomechanics, Jan 20, 2017

The present research aimed to describe an inertial unit (IU)-based sprint mechanics evaluation mo... more The present research aimed to describe an inertial unit (IU)-based sprint mechanics evaluation model for assessing players' readiness to return to competition after suffering a grade I hamstring injury. A professional male football player (age 19years; height 177cm; weight 70kg, midfielder, Spanish, 3° Division) with a grade 1 biceps femoris injury was evaluated at pre-season, at return to play after injury and at the end of the competitive season. Sprint mechanics were analyzed via the use of an inertial orientation tracker (Xsens Technologies B.V. Enschede, Netherlands) attached over the L3-L4 region of the subject's lumbar spine. Sprint mechanics such as horizontal components of ground reaction force were assessed in both legs during sprinting actions. Findings and interpretation: Both the coefficient of the horizontal force application (SFV) and the ratio of forces (DRF) applied at increasing velocity were decreased in the injured limb compared with the contralateral hea...

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, Nov 27, 2017

Frailty is characterized by a loss of functionality and is expected to affect 9.9% of people aged... more 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 classified according to Fried´s criteria. Both the 30-s chair stand test (CST) and the 3-m walking test were performed and a set of kinematic parameters were obtained from a single inertial unit. A decision tree analysis was used to: (1) identify the most relevant frailty-related parameters and (2) compare validity of this classification. We found that a selected set of parameters from the 30-s CST (i.e. range of movement, acceleration and power) were better at identifying frailty status than both the actual outcome of the test (i.e. cycles' number) and the normally used criteria (i.e. gait speed). For the pre-frail status, AUC improves from...

Computer methods and programs in biomedicine, 2017

In this paper we propose a novel single-channel harmonic and baseline noise removal approach base... more 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 representation approach admits efficient noise removal. The sparsity is improved by a modification of the time-frequency basis through the following signal processing steps: (1) spectrograms segmentation, (2) non-negative rank estimation, and (3) source grouping. The source waveforms are retrieved by means of non-negative matrix factorization and the overlap-add method. The proposed method was tested on real electrocardiogram and electromyogram signals for different analysis scenarios, against two state-of-the-art reference methods. Performance evaluation was carried out by means of the output signal-to-interference ratio. In the electrocardiogram analysis scenarios, for the inp...

Archives of Clinical Neuropsychology, 2017

Objective: Myotonic dystrophy type 1 (DM1), the most prevalent inherited neuromuscular disease in... more 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 their relationship with neurocognitive dysfunction. Methods: A total of 42 DM1 patients and 42 healthy controls were included in the study. Clinical, cognitive, and magnetic resonance imaging evaluations, including the use of structural and diffusion tensor imaging (DTI) techniques, were performed. White matter lesion (WML) load, volumetric analysis, and diffusivity changes were assessed and correlated with clinical and neuropsychological test findings. Results: WMLs were significantly more frequent in DM1 patients (p < .001), and anterior temporal lobe lesions were only found in the patient group. Global and regional cortical volume loss and corpus callosum atrophy were found. Diffuse white matter DTI abnormalities, including fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were observed with sparing of the internal capsule. Subcortical structures showed volume loss and increased median diffusivity. Neuropsychological evaluation showed significant impairment in several cognitive functions, but only visuospatial impairment was correlated with white matter abnormalities and cortical atrophy. Daytime sleepiness was associated with WML and ventral diencephalon and pallidum volume loss. Conclusion: DM1 produces a widespread involvement of white matter and gray matter, including cortical and subcortical structures. These structural abnormalities are involved in the progressive neuropsychological functional impairment in these patients

Dementia and geriatric cognitive disorders, Jan 27, 2016

Several studies have stated that frailty is associated with cognitive impairment. Based on variou... more 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 either dementia or frailty. Consequently, it is important to investigate dual task walking tests in elderly populations including control robust oldest old, frail oldest old with mild cognitive impairment (MCI) and frail oldest old without MCI. Dual task walking tests were carried out to examine the association between frailty and cognitive impairment in a population with advanced age. Forty-one elderly men and women participated in this study. The subjects from control, frail with MCI and frail without MCI groups, completed the 5-meter walk test at their own gait velocity. Arithmetic and verbal dual task walking performance was also assessed. Kinematic da...

European Psychiatry, 2016

IntroductionParkinsonian motor signs are the most frequent of the genuine motor abnormalities pre... more IntroductionParkinsonian 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).ObjectiveTo study whether there are differences in basal ganglia volumes depending on the presence of Parkinsonism in FEP.MethodsForty-six patients with a FEP were included in the study. Twenty-three controls were included to normalise patients’ brain volume data. Parkinsonism was assessed with the UKU scale. Brain volumes were obtained with MRI (1.5 Tesla Siemens Avanto). Reconstruction and volumetric segmentation was made with the Freesurfer© software (http://surfer.nmr.mgh.harvard.edu/). Patients were divided into two groups, considering the presence/absence of Parkinsonism (UKU total score cutoff point = 4). Patients have been treated with antipsychotics a mean of less than 2 months. There were not significant differences in the total exposure to antipsychotics bet...

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

We present a novel approach to single-channel power line interference (PLI) and baseline wander (... more 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, which represent the PLI, BW and EMG spectrogram estimates. They all exhibit very different time-frequency patterns: PLI and BW are both sparse whereas EMG is noise-like. Initialization of the classical NMF algorithm with accurately designed PLI, BW and EMG structures and a carefully adjusted matrix decomposition rank increases the separation performance. The comparative study suggests that the proposed method outperforms two state-of-the-art reference methods.

Journal of the American Medical Directors Association, 2016

Frailty has become the center of attention of basic, clinical, and demographic research because o... more 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 tests in frail populations. Insight into the relationships among muscle power, muscle quality, and functional capacity could improve the quality of life in this population. In this study, the relationship between the quality of the muscle mass and muscle strength with gait performance in a frail population was examined. Twenty-two institutionalized frail elderly individuals (93.1 ± 3.6) participated in this study. Muscle quality was measured by segmenting areas of high- and low-density fibers as observed in computed tomography images. The assessed functional outcomes were leg strength and power, velocity of gait, and kinematic gait parameters obtained from a tri-axial inertial sensor. Our results showed that a greater number of high-density fibers, specifically those of the quadriceps femoris muscle, were associated with better gait performance in terms of step time variability, regularity, and symmetry. Additionally, gait variability was associated with muscle power. In contrast, no significant relationship was observed between gait velocity and either muscle quality or muscle power. Gait pattern disorders could be explained by a deterioration of the lower limb muscles. It is known that an impaired gait is an important predictor of falls in older populations; thus, the loss of muscle quality and power could underlie the impairments in motor control and balance that lead to falls and adverse outcomes.

Journal of NeuroEngineering and Rehabilitation, 2015

Background: Physical frailty has become the center of attention of basic, clinical and demographi... more 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.

Proceedings of the Second Joint 24th Annual Conference and the Annual Fall Meeting of the Biomedical Engineering Society] [Engineering in Medicine and Biology

Independent component analysis (ICA) is one of the techniques proposed to solve the blind source ... more 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). Results agree with the classical SEP source modeling theory.

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)

... Miguel Valencia'72, Manuel Alegre', Julio Artieda', Armando Malanda2, Pablo Le... more ... Miguel Valencia'72, Manuel Alegre', Julio Artieda', Armando Malanda2, Pablo Lecumberri3,Marisol G6mez3. ... N. Velis, FH Lopes da Silva, “Enhace-ment of phase clustering in the EEG/MEG gamma frequency band anticipates transitions to paroxysmal epileptiform activity in ...

Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)

EEG stimulus-related responses have been extensively studied to gain insight on the functional be... more 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. Independent component analysis (ICA) is a technique widely used to solve