Problem Statement: Stepping is a common strategy after a perturbation. Stroke survivors display a predilection for stepping with non-paretic leg. Insight into induced stepping between stroke survivors and age-matched control may guide our understanding for reactive postural control training post stroke. Purpose: To investigate the difference in perturbation-induced stepping between chronic stroke survivors and age-matched controls at three phases of the stepping response: preparation, execution, and landing and association with clinical outcome measures. Procedure: Twenty-one community-dwelling chronic stroke survivors (mean age 59y/o ±13yrs) and 17 age- and gender-matched controls (mean age 54.4y/o ±17yrs) completed this study. Clinical measures of gait, balance, range, sensation, and motor control were assessed. A mechanical weight drop of 10% body weight (BW) was used to create the anterior waist pull perturbation during three stance symmetry positions: equal stance (EQ) and two asymmetrical stance (70% BW on dominant leg and 70% BW on nondominant leg). Ten perturbation trials plus two catch trials at 2% BW were given in a standard randomly order at the three stance positions. Kinematic and kinetic data was collected for perturbation steps. Results: The asymmetrical trials resulted in two types of stepping response, steps with the leg bearing 70% BW (loaded steps – LS) and steps with the leg that had 30% BW (unloaded steps – ULS). All subjects initiated steps more often with their unloaded leg (ULS) in the asymmetrical stance trials. In the stroke group the ULS increased paretic leg stepping compared to EQ (p=0.001) and LS (p=0.001). The stroke group had significantly earlier APA onset with both non-paretic leg (p=0.003) and paretic leg (p=0.028), took significantly more steps with paretic (p=0.01) and non-paretic (p=0.07), shorter step length (paretic, p=0.025 and non-paretic p=0.003), and less change in momentum at landing with paretic leg (p=0.01) compared to controls. Conclusion: Reacting to a perturbation is more challenging for chronic stroke survivors than age- and gender-matched control subjects in the preparation, execution, and landing phase of the stepping response regardless of the leg used. Perturbation training should include stepping with both non-paretic and paretic leg.

Made available in DSpace on 2016-12-06T17:07:29Z (GMT). No. of bitstreams: 1 Fabio.pdf: 1333634 bytes, checksum: ba66af05f0145d83e4b237a603a81d74 (MD5) Previous issue date: 2011-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to examine the influence of the postural control in the handgrip strength modulation of the non paretic upper limb during activity to pick up an object and in individuals with hemiparesis after Stroke. We evaluated 15 subjects with hemiparesis (EG) and 15 healthy subjects (CG) aged 57.3 ± 55.5 and 10.17 ± 11.27 years old respectively. To characterize the EG, tests were performed for maximum grip strength, Fugl-Meyer, Semmes-Weinstein monofilament (SWM), sensitivity test moving touch-pressure (MTP) and balance testing BERG. The parameters for the control of grip strength were: force at the time of lifting the cup (Grip lift off), peak grip force (PGF), peak velocity (Pvel), latency (LT), static force (SF) and difference time (DT), made through an instrumented glass with a force sensor and a three axial accelerometer. The subjects performed a task of picking and lifting an object at a predetermined height and keep it statically suspended for a time and reposition it back on the table. For the parameter EF, LT and DT, any significant data was found. Grip strength parameters Grip lift off, Pvel were different between positions. The grip force modulation (PGF) was different between groups. When asked to raise the object the EG didn´t modulate the grip force in response to the withdrawal additional object weight. Through this study it was possible to determine the possible involvement in the control parameters of grip strength of non-paretic upper limb of subjects with hemiparesis. / Este trabalho teve como objetivo analisar a influência da condição postural sentado e em pé na adaptação do controle da força de preensão manual do membro superior não parético durante a atividade de pegar e levantar um objeto, em indivíduos com hemiparesia após acidente vascular encefálico (AVE). Foram avaliados 15 indivíduos com hemiparesia (GE) e 15 indivíduos saudáveis (GC) com idade de 57,3 ±10,17 e 55,5±11,27 anos respectivamente. Para caracterização do GE foram realizados os testes de força de preensão máxima, Fugl-Meyer, monifilamento de Semmes-Weinstein (MSW), teste de sensibilidade moving touch-pressure (MTP) e o teste de equilíbrio de BERG. Os parâmetros para o controle da força de preensão foram: força no momento de levantar o copo (FNML), pico da força de preensão (PFP), pico de velocidade (Pvel), latência (LT), força estática (FE) e diferença temporal (DT) realizado através de um copo instrumentado com um sensor de força e um acelerômetro triaxial. Os indivíduos realizaram uma tarefa de pegar e levantar um objeto uma altura pré-estabelecida, mantê-lo por um tempo e reposicioná-lo novamente a mesa realizaram 7 repetições com carga e 7 sem carga. A modulação da força de preensão nos parâmetros FNML e Pvel ocorreu de forma diferente nas posições sentado e em pé em ambos os grupos. A modulação da PFP foi diferente entre grupos. Ao levantar o objeto o GE não modulou a força de preensão em resposta a retirada do peso adicional do objeto. Para o parâmetro FE, LT e DT, não foram encontrados dados significantes. Através deste estudo foi possível verificar o possível comprometimento nos parâmetros do controle da força de preensão do membro superior não parético de indivíduos com hemiparesia.

This study aims to evaluate the effects of functional electrical stimulation on motor and functional abilities of paretic upper limb in patients after stroke. Specifically detects the immediate effect of functional electrostimulation on the increase of the active range of motion, reduction of the hand spasticity degree and the improvement of functional performance. The research covered a total of 6 patients after first stroke in the basin aretria middle cerebral artery. The research sample had a homogeneous distribution of the paresis heaviness from light, moderate, to severe. The research was conducted in total of three weeks, every working day, 60 minutes a day, with 30 minutes of indicated electrostimulation and 30 minutes of testing of monitored parameters. Patients were evaluated using the Modified Frenchay scale, Modified Tardieu scale and the range of motion goniometer. Research showed in 60 observations that the functional electrical stimulation has immediate and significant effect on increasing the active range of dorsal flexion motion of the wrist (p-value 0.043). The average improvement on 95% interval estimation is 0.08. During the monitoring of the improvement of the active range of wrist dorsal flexion motion between input and output examination there was no statistically significant...