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1.
Sensors (Basel) ; 19(17)2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31461827

RESUMO

Decreased physical activity in obese individuals is associated with a prevalence of cardiovascular and metabolic disorders. Physicians usually recommend that obese individuals change their lifestyle, specifically changes in diet, exercise, and other physical activities for obesity management. Therefore, understanding physical activity and sleep behavior is an essential aspect of obesity management. With innovations in mobile and electronic health care technologies, wearable inertial sensors have been used extensively over the past decade for monitoring human activities. Despite significant progress with the wearable inertial sensing technology, there is a knowledge gap among researchers regarding how to analyze longitudinal multi-day inertial sensor data to explore activities of daily living (ADL) and sleep behavior. The purpose of this study was to explore new clinically relevant metrics using movement amplitude and frequency from longitudinal wearable sensor data in obese and non-obese young adults. We utilized wavelet analysis to determine movement frequencies on longitudinal multi-day wearable sensor data. In this study, we recruited 10 obese and 10 non-obese young subjects. We found that obese participants performed more low-frequency (0.1 Hz) movements and fewer movements of high frequency (1.1-1.4 Hz) compared to non-obese counterparts. Both obese and non-obese subjects were active during the 00:00-06:00 time interval. In addition, obesity affected sleep with significantly fewer transitions, and obese individuals showed low values of root mean square transition accelerations throughout the night. This study is critical for obesity management to prevent unhealthy weight gain by the recommendations of physical activity based on our results. Longitudinal multi-day monitoring using wearable sensors has great potential to be integrated into routine health care checkups to prevent obesity and promote physical activities.


Assuntos
Técnicas Biossensoriais , Exercício Físico , Sono/fisiologia , Dispositivos Eletrônicos Vestíveis , Adulto , Feminino , Humanos , Estilo de Vida , Masculino , Movimento/fisiologia , Obesidade/fisiopatologia
2.
J Appl Biomech ; 35(6): 393­400, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31629341

RESUMO

Accurate and reliable detection of the onset of gait initiation is essential for the correct assessment of gait. Thus, this study was aimed at evaluation of the reliability and accuracy of 3 different center of pressure-based gait onset detection algorithms: A displacement baseline-based algorithm (method 1), a velocity baseline-based algorithm (method 2), and a velocity extrema-based algorithm (method 3). The center of pressure signal was obtained during 10 gait initiation trials from 16 healthy participants and 3 participants with Parkinson's disease. Intrasession and absolute reliability of each algorithm was assessed using the intraclass correlation coefficient and the coefficient of variation of center of pressure displacement during the postural phase of gait initiation. The accuracy was evaluated using the time error of the detected onset by each algorithm relative to that of visual inspection. The authors' results revealed that although all 3 algorithms had high to very high intrasession reliabilities in both healthy subjects and subjects with Parkinson's disease, methods 2 and 3 showed significantly better absolute reliability than method 1 in healthy controls (P = .001). Furthermore, method 2 outperformed the other 2 algorithms in both healthy subjects and subjects with Parkinson's disease with an overall accuracy of 0.80. Based on these results, the authors recommend using method 2 for accurate and reliable gait onset detection.

3.
Aging Clin Exp Res ; 30(9): 1101-1110, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29372541

RESUMO

BACKGROUND: Multicomponent intervention programs have been shown to be effective in reducing risk factors associated with falls, but the primary target population of these interventions is often low-functioning older adults. AIMS: The purpose of this study was to investigate the effectiveness of a multicomponent intervention program focusing on balance and muscle strength for independently functioning community-dwelling older adults. METHODS: Fifty-three independently functioning older adults, aged 80.09 ± 6.62 years, participated in a group exercise class (conducted 2 times/week for 8 weeks) emphasizing balance. Outcome measures were balance performance using the Fullerton Advanced Balance (FAB) scale and muscle strength using the Senior Fitness Test (SFT). RESULTS: The intervention improved balance (P < 0.001), and older adults who were classified as having high fall risks based on the FAB scores at pre-testing improved more than older adults who were classified as having low fall risks (P = 0.017). As a result, 22 participants transitioned from a high fall risk group at pre-testing to a low fall risk group at post-testing (P < 0.001). The intervention also enhanced both upper and lower muscle extremity strength based on SFT results (P < 0.001) regardless of participants' classification of fall risk status. CONCLUSIONS AND DISCUSSION: The multicomponent intervention conducted two times per week for 8 weeks was effective in improving balance and enhancing muscle strength of independently functioning older adults. The results underscore the importance of providing fall prevention interventions to healthy older adults, a population often not a target of balance interventions.


Assuntos
Acidentes por Quedas/prevenção & controle , Exercício Físico/fisiologia , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Vida Independente , Extremidade Inferior , Masculino , Fatores de Risco
4.
Exp Brain Res ; 217(2): 197-208, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22198575

RESUMO

The purpose of the study was to investigate the role of altered proprioception on anticipatory (APAs) and compensatory (CPAs) postural adjustments and their interaction. Nine healthy adults were exposed to external perturbations induced at the shoulder level while standing with intact or altered proprioception induced by bilateral Achilles tendon vibration. Visual information was altered (eyes open or closed) in both the conditions. Electrical activity of eight trunk and leg muscles and center of pressure (COP) displacements were recorded and quantified within the time intervals typical for APAs and CPAs. The results showed that when proprioceptive information was altered in eyes-open conditions, anticipatory muscle activity was delayed. Moreover, altered proprioceptive information resulted in smaller magnitudes of compensatory muscle activity as well as smaller COP displacements after the perturbation in both eyes-open and eyes-closed conditions. The outcome of the study provides information on the interaction between APAs and CPAs in the presence of altered proprioception.


Assuntos
Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Propriocepção/fisiologia , Adulto , Eletromiografia , Feminino , Humanos , Masculino , Movimento/fisiologia , Visão Ocular/fisiologia
5.
Exp Brain Res ; 212(3): 385-97, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21643717

RESUMO

The purpose of the study was to investigate the availability of vision and additional support on anticipatory (APA) and compensatory (CPA) postural adjustments and their interaction. Eight healthy adults were exposed to external perturbations induced at the shoulder level while standing with and without holding onto a walker in full vision and while blindfolded. Electrical activity of the trunk and leg muscles and center of pressure (COPAP) displacement were recorded and quantified within the time intervals typical of APA and CPA. The results showed that with full vision, there was no difference in both APA and CPA in standing with and without holding onto a walker. With subjects holding onto a walker, CPA in standing blindfolded were comparable to CPA in full vision; this was seen in changes in the electrical activity of most of the muscles at the individual muscle, joint, and the muscle group levels as well as in COPAP displacement. The findings suggest that (1) in conditions where vision is available, vision overrules simultaneously available proprioceptive information from the support, (2) while in conditions where vision is not available, proprioceptive information from the support or support itself could be substituted for vision. It is possible to suggest that using a non-stabilizing support could be a valuable strategy to improve postural control when visual information is not available or compromised.


Assuntos
Retroalimentação Fisiológica/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Postura/fisiologia , Visão Ocular/fisiologia , Adulto , Eletromiografia , Feminino , Humanos , Masculino , Movimento/fisiologia
6.
Exp Brain Res ; 212(1): 47-63, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21537967

RESUMO

Previous studies of postural preparation to action/perturbation have primarily focused on anticipatory postural adjustments (APAs), the changes in muscle activation levels resulting in the production of net forces and moments of force. We hypothesized that postural preparation to action consists of two stages: (1) Early postural adjustments (EPAs), seen a few hundred ms prior to an expected external perturbation and (2) APAs seen about 100 ms prior to the perturbation. We also hypothesized that each stage consists of three components, anticipatory synergy adjustments seen as changes in covariation of the magnitudes of commands to muscle groups (M-modes), changes in averaged across trials levels of muscle activation, and mechanical effects such as shifts of the center of pressure. Nine healthy participants were subjected to external perturbations created by a swinging pendulum while standing in a semi-squatting posture. Electrical activity of twelve trunk and leg muscles and displacements of the center of pressure were recorded and analyzed. Principal component analysis was used to identify four M-modes within the space of muscle activations using indices of integrated muscle activation. This analysis was performed twice, over two phases, 400-700 ms prior to the perturbation and over 200 ms just prior to the perturbation. Similar robust results were obtained using the data from both phases. An index of a multi-M-mode synergy stabilizing the center of pressure displacement was computed using the framework of the uncontrolled manifold hypothesis. The results showed high synergy indices during quiet stance. Each of the two stages started with a drop in the synergy index followed by a change in the averaged across trials activation levels in postural muscles. There was a very long electromechanical delay during the early postural adjustments and a much shorter delay during the APAs. Overall, the results support our main hypothesis on the two stages and three components of the postural preparation to action/perturbation. This is the first study to document anticipatory synergy adjustments in whole-body tasks. We interpret the results within the referent configuration hypothesis (an extension of the equilibrium-point hypothesis): The early postural adjustment is based primarily on changes in the coactivation command, while the APAs involve changes in the reciprocal command. The results fit an earlier hypothesis that whole-body movements are controlled by a neuromotor hierarchy where each level involves a few-to-many mappings organized to stabilize its overall output.


Assuntos
Antecipação Psicológica/fisiologia , Movimento/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
7.
Artif Cells Nanomed Biotechnol ; 47(1): 56-63, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30669860

RESUMO

s-allyl glutathione (SAG) an analogue of glutathione is explored for its antioxidative and liver protection property in recent years. Selenium nanoparticles (Sh-SeNPs) were synthesized using medicinal plant Spermacoce hispida and conjugated with SAG (SAG-Sh-SeNPs). SAG-Sh-SeNPs and Sh-SeNPs were characterized using by Fourier transform infrared spectroscopy, Transmission electron microscopy, Energy dispersive X-ray analysis, X-ray diffraction analysis and zeta potential analysis. SAG-Sh-SeNPs and Sh-SeNPs were evaluated against acetaminophen (APAP)-induced liver and kidney injury in rat. Pretreatment of NPs attenuated the APAP toxicity-induced elevation of kidney and liver injury markers in the blood circulation. Histological observation showed that NPs pretreatment protected the morphology of liver and kidney tissue. SAG-Sh-SeNPs showed enhanced protection against APAP toxicity in comparison to Sh-SeNPs due to synergistic effect of SAG and Sh-SeNPs. SAG-Sh-SeNPs protected the liver and kidney against APAP toxicity through reducing oxidative stress, enhancing endogenous antioxidants and protecting mitochondrial functions.


Assuntos
Acetaminofen/toxicidade , Glutationa/química , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Nanopartículas/química , Rubiaceae/química , Selênio/farmacologia , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Química Verde , Rim/citologia , Rim/metabolismo , Fígado/citologia , Fígado/metabolismo , Masculino , Fosforilação Oxidativa/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Selênio/química
8.
Clin Neurophysiol ; 119(10): 2274-81, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18760664

RESUMO

OBJECTIVE: To evaluate the methodology for exploring the specific aspects of functional impairment in multiple sclerosis (MS) through the pattern of forces exerted in various manipulation tasks. METHODS: Twelve mildly involved MS patients (EDSS 2.5-5.5) and 12 healthy controls performed various static and dynamic manipulation tasks with an instrumented device that recorded the grip (G; normal to the digit device contact area) and load force (L; tangential force that causes lifting). RESULTS: MS patients consistently displayed lower indices of task performance (as assessed by the ability to produce the required L profiles) and force coordination (as assessed by G/L ratio, coupling of G and L, and G modulation) than the healthy controls across all tested tasks. CONCLUSIONS: The applied methodology could be sensitive enough to detect the hand dysfunction in mildly involved individuals with MS. Particularly recommended for future evaluations of the impairment of hand function could be a simple lifting task and the static task of tracing a gradually changing L, as well as the variables depicting both the task performance and G/L ratio. SIGNIFICANCE: The applied methodology could be developed into a standard clinical test for the assessment of hand function in MS and, possibly, in other neurological diseases.


Assuntos
Força da Mão/fisiologia , Mãos/fisiopatologia , Esclerose Múltipla/patologia , Esclerose Múltipla/fisiopatologia , Desempenho Psicomotor/fisiologia , Adulto , Idoso , Estudos de Casos e Controles , Avaliação da Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Suporte de Carga
9.
Neurosci Lett ; 434(2): 234-9, 2008 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-18313221

RESUMO

Both an elaborate coordination of the hand grip force (G; normal component of force acting at the digits-object contact area) and load force (L; tangential component), and the role of cutaneous afferents in G-L coordination have been well documented in a variety of manipulation tasks. However, our recent studies revealed that G-L coordination deteriorates when L consecutively changes direction (bidirectional tasks; e.g., when vigorously shaking objects or using tools). The aim of the study was to distinguish between the possible role of the synergy of hand grip and arm muscles (exerting G and L, respectively) and the role of cutaneous afferent input in the observed phenomenon. Subjects (N=14) exerted sinusoidal L pattern in vertical direction against an externally fixed device in trials that gradually changed from uni- to fully bidirectional. In addition, a manipulation of an external arm support decoupled L measured by the device (and, therefore, recorded by the cutaneous receptors) from the action of arm muscles exerting L. The results revealed that switching from uni- to bidirectional tasks, no matter how low and brief L exertion was in the opposite direction, was associated with an abrupt decrease in G-L coordination. This coordination remained unaffected by the manipulation of external support. The first result corroborates our previous conclusion that the force coordination in uni- and bidirectional manipulation tasks could be based on partly different neural control mechanisms. However, the second finding suggests that the studied control mechanisms could depend more on the cutaneous afferent input, rather than on the synergy of the muscles exerting G and L.


Assuntos
Movimento/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Neurônios Aferentes/fisiologia , Pele/inervação , Adulto , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Modelos Biológicos , Contração Muscular/fisiologia , Fenômenos Fisiológicos da Pele
10.
Environ Technol ; 39(11): 1376-1383, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28488473

RESUMO

The aqueous extract of various plants like Coriandrum sativum (AECS), Alternanthera tenella colla (AEAT), Spermacoce hispida (AESH) and Mollugo verticillata (AEMV) was studied for its hexavalent chromium (CrVI) reduction property. Even though antioxidant activity was present, AEAT, AESH and AEMV did not reduce CrVI. AECS showed rapid and dose-dependent CrVI reduction. The efficient reduction of 50 mg/L of CrVI using AECS was attained in the presence of 250 µg/mL of starting plant material, incubating the reaction mixture at pH 2, 30°C and agitation at 190 rpm. Under such conditions, about 40 mg/L of CrVI was reduced at 3 h of incubation. FT-IR analysis revealed the involvement of phenols, alcohols, alpha-hydroxy acid and flavonoids present in the AECS for the CrVI reduction. These results indicate that not all the plant extracts with rich antioxidants are capable of reducing CrVI. Using the conditions standardized in the present study, AECS reduced about 80% of CrVI present in the tannery effluent. These results signify the application of AECS as an eco-friendly method in the wastewater treatment.


Assuntos
Cromo/química , Extratos Vegetais , Poluentes Químicos da Água/química , Purificação da Água , Biodegradação Ambiental , Resíduos Industriais , Oxirredução , Espectroscopia de Infravermelho com Transformada de Fourier
11.
Artif Cells Nanomed Biotechnol ; 46(7): 1488-1494, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28885044

RESUMO

Silver nanoparticles (AgNPs) were biosynthesized using Bauhinia variegata flower extract (BVFE). The BVF-AgNPs was found to be spherical shaped with the size of 5-15 nm. The phytoconstituents analysis and FTIR spectrum indicated that bioactive compounds like, phenols, flavonoids, benzophenones, nitro compounds, aromatics and aliphatic amines from BVFE might absorb on the surface of BVF-AgNPs. The synthesized BVF-AgNPs showed potent antioxidant property and α-amylase enzyme activity inhibition. The IC50 value of BVF-AgNPs was found to be 4.64 and 16.6 µg/ml for DPPH and ferric reducing power assay, respectively. The IC50 value of BVF-AgNPs for α-amylase inhibition was found to be 38 µg/ml. The Ki value of BVF-AgNPs for α-amylase inhibitory effect was found to be 21 µg/ml with the non-competitive mode of inhibition. These results suggest that BVF-AgNPs might be an effective nano-drug to treat diabetic conditions.


Assuntos
Bauhinia/química , Flores/química , Nanopartículas Metálicas/química , Extratos Vegetais/metabolismo , Prata/química , Prata/farmacologia , alfa-Amilases/antagonistas & inibidores , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Prata/metabolismo
12.
Neurosci Lett ; 412(2): 179-84, 2007 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-17125925

RESUMO

Exceptional coordination of grip (G; the normal force that prevents slippage of the grasped object) and load force (L; the tangential force originating from the object's weight and inertia) has been interpreted as a part of evidence that both the anatomy and neural control of human hands have been predominantly designed for manipulation tasks. In the present study, we tested the hypothesis that the precision grasp (uses only the tips of fingers and the thumb of one hand) provides better indices of G and L coordination in static manipulation tasks than two bimanual grasps (palm-palm and fingers-thumb; both using opposing segments of two hands). However, in addition to a subtle difference in relative timing of G and L between the precision and two bimanual grasps, we only found that the fingers-thumb grasp is characterized with higher G/L ratio and somewhat higher modulation of G than not only the precision, but also the bimanual palm-palm grasp. However, all remaining data including the correlation coefficients between G and L demonstrated no difference among three evaluated grasping techniques. Therefore, we concluded that the elaborate G and L coordination associated with uni-manual grasps could be partly generalized to a variety of manipulation tasks including those based on bimanual grasping techniques. Taking into account the importance of manipulation tasks in both everyday life and clinical evaluation, future studies should extend the present research to both other grasping techniques and dynamic manipulation conditions.


Assuntos
Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Mãos/fisiologia , Adaptação Fisiológica/fisiologia , Adulto , Relógios Biológicos/fisiologia , Fenômenos Biomecânicos , Feminino , Dedos/fisiologia , Humanos , Contração Isométrica/fisiologia , Masculino , Destreza Motora/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Valores de Referência , Suporte de Carga/fisiologia
13.
Exp Brain Res ; 183(4): 487-97, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17665176

RESUMO

A number of studies have demonstrated high coordination of the hand grip force (GF; normal component of force acting at the digits-object contact area) and load force (LF; tangential component) in a variety of manipulation tasks. The aim of the study was to explore the mainly neglected effect of the change in LF direction and the effect of handedness on GF and LF coordination in bimanual manipulation task. Subjects (N = 14) exerted a bimanual sinusoidal LF pattern against externally fixed handles in trials that gradually changed from unidirectional (LF exerted only in one direction) to fully bidirectional (equal LF peaks in two opposite directions). Despite the gradual change of LF, unidirectional trials demonstrated high indices of force coordination, while in all bidirectional trials, no matter how low and brief LF exertion was in the opposite direction, all indices of GF and LF coordination deteriorated to a considerably lower level. The non-dominant hand demonstrated both a higher directional accuracy of exerting LF and higher GF modulation than the dominant one. We concluded that manipulation tasks performed in a single and two alternating directions may be based on partly distinctive neural control mechanisms, as well as that a switching of muscle synergies required in bidirectional tasks could play a role in the observed phenomenon. Regarding the effect of hand dominance, the recorded advantage of the non-dominant hand could be considered as an addition to the current views of the non-dominant arm/hemisphere specialization in controlling limb position.


Assuntos
Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Mãos , Desempenho Psicomotor/fisiologia , Estresse Mecânico , Suporte de Carga/fisiologia , Adulto , Feminino , Dedos/fisiologia , Humanos , Contração Isométrica/fisiologia , Masculino , Músculo Esquelético/fisiologia
14.
Gait Posture ; 57: 136-140, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28624710

RESUMO

While cognitive-motor interference in dual-task activities is well established, it is still unknown how such interference is influenced by concurrent visual challenges. Nineteen community-dwelling healthy, cognitively intact, older adults (Mean±SD=71.45±1.25years, 6 males) and nineteen young adults (Mean±SD=22.25±0.68years, 4 males) performed a cognitive-single-task (serial subtraction by 3), a walking-single-task and a cognitive-walking-dual-task under normal, blurred and peripheral-vision-loss conditions (artificially imposed using goggles). Gait parameters and the number of correct responses were measured. Dual task costs for both walking and cognition were computed. Results showed that higher walking cost was seen with impaired vision (p=0.05) and with older adults (p=0.03); greater cognitive cost was seen with impaired vision (p=0.01), but no difference in cognitive cost was seen between young and older adults. Thus, when faced with impaired vision, both young and older adults appear to allocate less attention to cognition than to walking, and thus prioritize walking. Future work should explore whether dual-task training under visual challenge could reduce cognitive-motor interference and reduce fall risks in older adults.


Assuntos
Envelhecimento/fisiologia , Cognição/fisiologia , Marcha/fisiologia , Transtornos da Visão/fisiopatologia , Acuidade Visual , Caminhada/legislação & jurisprudência , Idoso , Atenção , Feminino , Humanos , Masculino , Prognóstico , Análise e Desempenho de Tarefas , Caminhada/fisiologia , Adulto Jovem
15.
Biomed Eng Lett ; 7(4): 287-298, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30603178

RESUMO

In this work, we develop a device, called 'Walk-Even', that can provide real-time feedback to correct gait asymmetry commonly exhibited in post-stroke survivors and persons with certain neurological disorders. The device computes gait parameters, including gait time, swing time, and stance time of each leg, to detect gait asymmetry and provide corresponding real-time biofeedback by means of auditory and electrotactile stimulation to actively correct the user's gait. The system consists of customized force-sensor-embedded insoles adjustable to fit any shoe size, electrotactile and auditory feedback circuits, microcontroller, and wireless XBee transceivers. The device also offers data saving capability. To validate its accuracy and reliability, we compared the gait measurements from our device with a commercial gait and balance assessment device, Zeno Walkway. The results show good correlation and agreement in a validity study with six healthy subjects and reliability study with seventeen healthy subjects. In addition, preliminary testing on six post-stroke patients after an 8-week training shows that the Walk-Even device helps to improve gait symmetry, foot pressure and forefoot loading of the affected side. Thus, initial testing indicates that the device is accurate in measuring the gait parameters and effective in improving gait symmetry using real-time feedback. The device is portable and low cost and has the potential for use in a non-clinical setting for patients that can walk independently without assistance. A more extensive testing with stroke patients is still ongoing.

16.
J Rehabil Med ; 48(9): 781-786, 2016 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-27630015

RESUMO

OBJECTIVE: Ankle joint control plays an important role in independent walking. This study investigated the effects of robotic-assisted locomotor training on impaired ankle joint control in individuals with chronic incomplete spinal cord injury. METHODS: Sixteen individuals with incomplete spinal cord injury underwent 12 one-h sessions of robotic-assisted locomotor training for 4 weeks, while 16 individuals with incomplete spinal cord injury served as inactive controls. Changes in ankle control measures, torque and co-activation were evaluated during maximal voluntary contractions in dorsi- and plantar-flexion. Changes in walking performance measures using Timed Up and Go (TUG), 10-m walk (10MWT) and 6-min walk (6MWT) tests were evaluated at 2 time points: baseline and after 4 weeks. RESULTS: Maximal voluntary contractions torque during both dorsi- and plantar-flexion contractions improved markedly in the robotic-assisted locomotor training group compared with baseline. Furthermore, after the training, co-activation during the dorsi-flexion maximal voluntary contractions decreased in the training group compared with controls. In addition, the training group significantly improved walking mobility (TUG) and speed (10MWT) compared with baseline. Finally, correlation analysis indicated a significant linear relationship between maximal voluntary contraction torques and walking performance measures. CONCLUSION: These findings provide evidence that robotic-assisted locomotor training improves ankle joint control, which may translate into enhanced walking performance in individuals with chronic incomplete spinal cord injury.


Assuntos
Articulação do Tornozelo/fisiopatologia , Tornozelo/fisiopatologia , Modalidades de Fisioterapia/instrumentação , Robótica/métodos , Traumatismos da Medula Espinal/reabilitação , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Torque
17.
Gait Posture ; 38(4): 923-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23711985

RESUMO

To ensure stability during gait, mediolateral placement of the swinging foot must be actively regulated. Logically this occurs through end-point control of the swing limb trajectory, the precision of which is quantified as step-width variability (SWV). Increased SWV with age may reflect reduced precision of this control, but cannot describe if, and how, age-related changes in lower limb kinematic synergies account for reduced precision. We analyzed joint configuration variance across steps within the uncontrolled manifold (UCM) hypothesis, which assumes that redundant sets of elemental variables are organized by the central nervous system to stabilize important performance variables. We tested whether: (1) regardless of age, the swing limb trajectory would be stabilized by a kinematic synergy of the lower limbs, and (2) the strength of the synergy would be weaker in older adults. Ten younger and ten older adults (65+ years) walked on a laboratory walkway at their preferred speed while kinematic data were collected. UCM analysis of segmental configuration variance was performed with respect to the mediolateral trajectory of the swing-limb ankle joint center. Throughout most of swing, the trajectory was stabilized by a kinematic synergy. Despite the greater segmental configuration variance of older adults, the strength of the synergy was not significantly different between groups. Moreover, the synergy index became negative during terminal swing and was not significantly correlated with SWV. Accordingly, co-variation among individual segmental trajectories is more important for stabilization of the swing trajectory during mid-swing, and, throughout swing, aging does not appear to affect this stabilization.


Assuntos
Envelhecimento/fisiologia , Marcha/fisiologia , Perna (Membro)/fisiologia , Movimento/fisiologia , Adulto , Idoso , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Humanos , Adulto Jovem
18.
Clin Neurophysiol ; 123(1): 173-82, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21778109

RESUMO

OBJECTIVES: The goal of this study was to investigate the effect of visual acuity on the anticipatory (APAs) and compensatory (CPAs) components of postural control. METHODS: Ten individuals participated in the experiments involving perturbations induced by a pendulum while their visual acuity was altered. The different visual acuity conditions were no glasses, blurred vision induced by wearing glasses with positive or negative lenses, and no vision. EMG activity of trunk and leg muscles and ground reaction forces were recorded during the typical anticipatory and compensatory periods. RESULTS: In the no vision condition the subjects did not generate APAs, which resulted in the largest displacements of the center of pressure (COP) after the perturbation (p<0.01). In all other visual conditions APAs were present showing a distal to proximal order of muscle activation. The subjects wearing positive glasses showed earlier and larger anticipatory EMGs than subjects wearing negative glasses or no glasses at all. CONCLUSIONS: The study outcome revealed that changes in visual acuity induced by wearing differently powered eye glasses alter the generation APAs and as a consequence, affect the compensatory components of postural control. SIGNIFICANCE: The observed changes in APAs and CPAs in conditions with blurred vision induced by positive and negative glasses suggest the importance of using glasses with an appropriate power. This outcome should be taken into consideration in balance rehabilitation of individuals wearing glasses.


Assuntos
Equilíbrio Postural/fisiologia , Baixa Visão/fisiopatologia , Acuidade Visual/fisiologia , Adulto , Eletromiografia , Óculos , Feminino , Humanos , Perna (Membro)/fisiologia , Masculino , Músculo Esquelético/fisiologia , Adulto Jovem
19.
Gait Posture ; 36(2): 225-30, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22483546

RESUMO

The aim of the present study was to investigate the organization of anticipatory postural adjustments (APAs) in individuals with multiple sclerosis (MS) during self-initiated perturbation in the sagittal plane. Eleven individuals with MS and eleven age-and-gender matched healthy controls were asked to hold a 2.27 kg load in the extended arms and release it using fast arm abduction movements. Electrical activity of six leg and trunk muscles as well as displacements of the center of pressure (COP) were recorded. The results indicate that individuals with MS (1) demonstrate a reduced magnitude of APAs, (2) delayed latency of APAs and (3) smaller anticipatory COP displacement as compared to healthy control subjects. Moreover, in spite of individuals with MS being mildly affected, their balance capacity was significantly diminished. Thus, the outcome of this study demonstrates the underlying impairment in anticipatory postural control of individuals with MS and provides a background for development of rehabilitation strategies focused on balance restoration in this population.


Assuntos
Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Equilíbrio Postural/fisiologia , Antecipação Psicológica , Braço/fisiopatologia , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Suporte de Carga
20.
Neurosci Lett ; 506(2): 256-60, 2012 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-22154279

RESUMO

Individuals with multiple sclerosis (MS) frequently exhibit difficulties in balance maintenance. It is known that anticipatory postural adjustments (APAs) play an important role in postural control. However, no information exists on how people living with MS utilize APAs for control of posture. A group of individuals with MS and a group of healthy control subjects performed rapid arm flexion and extension movements while standing on a force platform. Electromyographic (EMG) activity of six trunk and leg muscles and displacement of center of pressure (COP) were recorded and quantified within the time intervals typical of APAs. Individuals with MS demonstrated diminished ability to produce directional specific patterns of anticipatory EMGs as compared to control subjects. In addition, individuals with MS demonstrated smaller magnitudes of anticipatory muscle activation. This was associated with larger displacements of the COP during the balance restoration phase. These results suggest the importance of anticipatory postural control in maintenance of vertical posture in individuals with MS. The outcome of the study could be used while developing rehabilitation strategies focused on balance restoration in individuals with MS.


Assuntos
Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Equilíbrio Postural/fisiologia , Transtornos de Sensação/fisiopatologia , Antecipação Psicológica , Eletromiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Postura/fisiologia
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