Reliability of two methods for identifying the postural phase of gait initiation in healthy and post-stroke subjects

This study aims to compare two methods of assessing the postural phase of gait initiation as to intrasession reliability, in healthy and post-stroke subjects. As a secondary aim, this study aims to analyse anticipatory postural adjustments during gait initiation based on the centre of pressure (CoP) displacements in post-stroke participants. The CoP signal was acquired during gait initiation in fifteen post-stroke subjects and twenty-three healthy controls. Postural phase was identified through a baseline-based method and a maximal displacement based method. In both healthy and post-stroke participants higher intra-class correlation coefficient and lower coefficient of variation values were obtained with the baseline-based method when compared to the maximal displacement based method. Post-stroke participants presented decreased CoP displacement backward and toward the first swing limb compared to controls when the baseline-based method was used. With the maximal displacement based method, there were differences between groups only regarding backward CoP displacement. Postural phase duration in medial-lateral direction was also increased in post-stroke participants when using the maximal displacement based method. The findings obtained indicate that the baseline-based method is more reliable detecting the onset of gait initiation in both groups, while the maximal displacement based method presents greater sensitivity for post-stroke participants

Towards an efficient and robust foot classification from pedobarographic images

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).This paper presents a new computational framework for automatic foot classification from digital plantar pressure images. It classifies the foot as left or right and simultaneously calculates two well-known footprint indices: the Cavanagh's arch index and the modified arch index. The accuracy of the framework was evaluated using a set of plantar pressure images from two common pedobarographic devices. The results were outstanding, since all feet under analysis were correctly classified as left or right and no significant differences were observed between the footprint indices calculated using the computational solution and the traditional manual method. The robustness of the proposed framework to arbitrary foot orientations and to the acquisition device was also tested and confirmed

Spatio-temporal alignment of pedobarographic image sequences

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).This paper presents a methodology to align plantar pressure image sequences simultaneously in time and space. The spatial position and orientation of a foot in a sequence are changed to match the foot represented in a second sequence. Simultaneously with the spatial alignment, the temporal scale of the first sequence is transformed with the aim of synchronizing the two input footsteps. Consequently, the spatial correspondence of the foot regions along the sequences as well as the temporal synchronizing is automatically attained, making the study easier and more straightforward. In terms of spatial alignment, the methodology can use one of four possible geometric transformation models: rigid, similarity, affine or projective. In the temporal alignment, a polynomial transformation up to the 4th degree can be adopted in order to model linear and curved time behaviors. Suitable geometric and temporal transformations are found by minimizing the mean squared error (MSE) between the input sequences. The methodology was tested on a set of real image sequences acquired from a common pedobarographic device. When used in experimental cases generated by applying geometric and temporal control transformations, the methodology revealed high accuracy. Additionally, the intra-subject alignment tests from real plantar pressure image sequences showed that the curved temporal models produced better MSE results (p<0.001) than the linear temporal model. This paper represents an important step forward in the alignment of pedobarographic image data, since previous methods can only be applied on static images

Influence of an unstable shoe on compensatory postural adjustments: An experimental evaluation

This study attempted to evaluate the influence of using an unstable shoe in muscle recruitment strategies and center of pressure (CoP) displacement after the application of an external perturbation. Fourteen healthy female subjects participated in this study. The electromyographic activity of medial gastrocnemius, tibialis anterior, rectus femoris, biceps femoris, rectus abdominis and erector spinae muscles and the kinetic values to calculate the CoP were collected and analyzed after the application of an external perturbation with the subject in standing position, with no shoes and using unstable footwear. The results showed increased in medial gastrocnemius activity during the first compensatory postural adjustments and late compensatory postural adjustments when using an unstable shoe. There were no differences in standard deviation and maximum peak of anteroposterior displacement of CoP between measurements. From the experimental findings, one can conclude that the use of an unstable shoe leads to an increase in gastrocnemius activity with no increase in CoP displacement following an unexpected external perturbation

Effects of dual-task training on balance and executive functions in Parkinson's disease: a pilot study

The aim of this study was to analyze the efficacy of cognitive-motor dual-task training compared with single-task training on balance and executive functions in individuals with Parkinson's disease. Fifteen subjects, aged between 39 and 75 years old, were randomly assigned to the dual-task training group (n = 8) and single-task training group (n = 7). The training was run twice a week for 6 weeks. The single-task group received balance training and the dual-task group performed cognitive tasks simultaneously with the balance training. There were no significant differences between the two groups at baseline. After the intervention, the results for mediolateral sway with eyes closed were significantly better for the dual-task group and anteroposterior sway with eyes closed was significantly better for the single-task group. The results suggest superior outcomes for the dual-task training compared to the single-task training for static postural control, except in anteroposterior sway with eyes closed

Interlimb coordination during the stance phase of gait in subjects with stroke

To analyze the relation between contralesional and ipsilesional limbs in subjects with stroke during step-to-step transition of walking. Observational, transversal, analytical study with a convenience sample. Physical medicine and rehabilitation clinic. Participants: Subjects (nZ16) with poststroke hemiparesis with the ability to walk independently and healthy controls (nZ22). Interventions: Not applicable. Main Outcome Measures: Bilateral lower limbs electromyographic activity of the soleus (SOL), gastrocnemius medialis, tibialis anterior, biceps femoris, rectus femoris, and vastus medialis (VM) muscles and the ground reaction force were analyzed during double-support and terminal stance phases of gait. The propulsive impulse of the contralesional trailing limb was negatively correlated with the braking impulse of the leading limb during double support (rZ .639, PZ.01). A moderate functional relation was observed between thigh muscles (rZ .529, PZ.035), and a strong and moderate dysfunctional relation was found between the plantar flexors of the ipsilesional limb and the vastus medialis of the contralesional limb, respectively (SOL-VM, rZ .80, P<.001; gastrocnemius medialis-VM, rZ .655, PZ.002). Also, a functional moderate negative correlation was found between the SOL and rectus femoris muscles of the ipsilesional limb during terminal stance and between the SOL (rZ .506, PZ.046) and VM (rZ .518, PZ.04) muscles of the contralesional limb during loading response, respectively. The trailing limb relative impulse contribution of the contralesional limb was lower than the ipsilesional limb of subjects with stroke (PZ.02) and lower than the relative impulse contribution of the healthy limb (PZ.008) during double support. The findings obtained suggest that the lower performance of the contralesional limb in forward propulsion during gait is related not only to contralateral supraspinal damage but also to a dysfunctional influence of the ipsilesional limb

Association between dietary calcium intake and blood pressure among portuguese children

Higher blood pressure (BP) in childhood is associated with cardiovascular risk. It has been described that dietary calcium intake may affect BP regulation. The objective of this study was to analyze the association between dietary calcium intake and BP in children.info:eu-repo/semantics/publishedVersio

Soleus and Brachioradialis Muscles Modulationin APAs Recruitment Prior to Stand to Sit and Gait – A Pilot Study in Post Stroke Subjects

Neural coupling, frequently impaired in post-stroke subjects, can be assessed through upper limb flexor components against gravitiy like the brachioradialis muscles activity. Based on the known infkuence of the lower limb activity in the upper limb motor behavior it can be raised the question on whether the dysfunctional modulation of the extensors also happens in the brachioradialis muscle.info:eu-repo/semantics/publishedVersio

Análise da sequência do movimento de levantar/sentar, em indivíduos pós AVE: Estudo da relação da activação dos músculos vasto medial oblíquo e vasto lateral

O objectivo deste estudo foi comparar o rácio dos músculos Vasto Medial Oblíquo (VMO) e Vasto Lateral (VL), na sequência de movimento de levantar e sentar, em indivíduos sem patologia e em indivíduos com Acidente Vascular Encefálico (AVE). Pretendeu-se também verificar a sequência de activação de alguns músculos do membro inferior na sequência de movimento de levantar. Verificou-se existir diferenças significativas para afirmar que, no movimento de levantar, indivíduos com sequelas de AVE apresentam menor rácio VMO/VL no membro predominantemente atingido em relação aos indivíduos sem patologia. Diferentes sequências de activação muscular durante o movimento de levantar foram observadas.The purpose of this study was to compare the ratio of the Vastus medialis oblique (VMO) and vastus lateralis (VL), in sit-to-stand movement in subjects without pathology and in individuals with stroke. The article tries to verify the sequence of activation of some muscles of the lower limb during standing up. There are significant differences to argue that, in standing up movement, subjects with sequelae of stroke have a lower ratio VMO / VL in predominantly affected limb compared to subjects without pathology. Different sequences of muscle activation during standing up movement were observed

Post-stroke patients functional task characterization through accelerometry data for rehabilitation intervention and monitoring

An increasing ageing society and consequently rising number ofpost-stroke related neurological dysfunction patients are forcing therehabilitation field to adapt to ever-growing demands. Compensatorymovements related to available motor strategies, can be observed inpost-stroke patients when performing functional tasks due to apathological synergy as in reaching for an object. Studies of post-strokemotor recovery suggest that such maladaptive strategies may limit theplasticity of the nervous system to enhance neuromotor recovery.Strategies for rehabilitation protocols monitoring and validation arepresently a necessity, moreover considering data recording is oftenabsent of the rehabilitation process or subjective in nature.Characterization strategies of patient performance during functional taskare key aspects for clinical protocols validation, progress monitoring andmethodologies comparison. This project seeks to characterize patientsupper limb performance through accelerometry, gathered with a lowcostwearable system, for compensatory movement avoidance throughfeedback response