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Detalhes

Detalhes

  • Nome

    Flora Rocha Ferreira
  • Cluster

    Informática
  • Cargo

    Investigador Colaborador Externo
  • Desde

    01 setembro 2017
002
Publicações

2019

Gait stride-to-stride variability and foot clearance pattern analysis in Idiopathic Parkinson's Disease and Vascular Parkinsonism

Autores
Ferreira, F; Gago, MF; Bicho, E; Carvalho, C; Mollaei, N; Rodrigues, L; Sousa, N; Rodrigues, PP; Ferreira, C; Gama, J;

Publicação
Journal of Biomechanics

Abstract
The literature on gait analysis in Vascular Parkinsonism (VaP), addressing issues such as variability, foot clearance patterns, and the effect of levodopa, is scarce. This study investigates whether spatiotemporal, foot clearance and stride-to-stride variability analysis can discriminate VaP, and responsiveness to levodopa. Fifteen healthy subjects, 15 Idiopathic Parkinson's Disease (IPD) patients and 15 VaP patients, were assessed in two phases: before (Off-state), and one hour after (On-state) the acute administration of a suprathreshold (1.5 times the usual) levodopa dose. Participants were asked to walk a 30-meter continuous course at a self-selected walking speed while wearing foot-worn inertial sensors. For each gait variable, mean, coefficient of variation (CV), and standard deviations SD1 and SD2 obtained by Poincaré analysis were calculated. General linear models (GLMs) were used to identify group differences. Patients were subject to neuropsychological evaluation (MoCA test) and Brain MRI. VaP patients presented lower mean stride velocity, stride length, lift-off and strike angle, and height of maximum toe (later swing) (p < .05), and higher %gait cycle in double support, with only the latter unresponsive to levodopa. VaP patients also presented higher CV, significantly reduced after levodopa. Yet, all VaP versus IPD differences lost significance when accounting for mean stride length as a covariate. In conclusion, VaP patients presented a unique gait with reduced degrees of foot clearance, probably correlated to vascular lesioning in dopaminergic/non-dopaminergic cortical and subcortical non-dopaminergic networks, still amenable to benefit from levodopa. The dependency of gait and foot clearance and variability deficits from stride length deserves future clarification. © 2019 Elsevier Ltd

2018

Position-based kinematics for 7-DoF serial manipulators with global configuration control, joint limit and singularity avoidance

Autores
Faria, C; Ferreira, F; Erlhagen, W; Monteiro, S; Bicho, E;

Publicação
Mechanism and Machine Theory

Abstract
This paper presents a novel analytic method to uniquely solve inverse kinematics of 7 degrees-of-freedom manipulators while avoiding joint limits and singularities. Two auxiliary parameters are introduced to deal with the self-motion manifolds: the global configuration (GC), which specifies the branch of inverse kinematics solutions; and the arm angle (?) that parametrizes the elbow redundancy within the specified branch. The relations between the joint angles and the arm angle are derived, in order to map the joint limits and singularities to arm angle values. Then, intervals of feasible arm angles for the specified target pose and global configuration are determined, taking joint limits and singularities into account. A simple metric is proposed to compute the elbow position according to the feasible intervals. When the arm angle is determined, the joint angles can be uniquely calculated from the position-based inverse kinematics algorithm. The presented method does not exhibit the disadvantages inherent to the use of the Jacobian matrix and can be implemented in real-time control systems. This novel algorithm is the first position-based inverse kinematics algorithm to solve both global and local manifolds, using a redundancy resolution strategy to avoid singularities and joint limits. © 2017 Elsevier Ltd

2018

Foot clearance pattern: a distinctive gait variable in vascular Parkinson's disease

Autores
Gago, MF; Ferreira, F; Carvalho, C; Mollaei, N; Bicho, E; Rodrigues, L; Sousa, N; Gama, J; Ferreira, C;

Publicação
EUROPEAN JOURNAL OF NEUROLOGY

Abstract

2018

Artificial Neural Networks Classification of Patients with Parkinsonism based on Gait

Autores
Fernandes, C; Fonseca, L; Ferreira, F; Gago, M; Costa, L; Sousa, N; Ferreira, C; Gama, J; Erlhagen, W; Bicho, E;

Publicação
IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2018, Madrid, Spain, December 3-6, 2018

Abstract

2017

Gait analysis as a complementary tool in the levodopa dose decision in vascular Parkinson's disease

Autores
Gago, M; Ferreira, F; Mollaei, N; Rodrigues, M; Sousa, N; Bicho, E; Rodrigues, P;

Publicação
MOVEMENT DISORDERS

Abstract