Daniel Gustavo Goroso

Preparatory EMG Activity Reveals a Rapid Adaptation Pattern in Humans Performing Landing Movements in Blindfolded Condition

The main questions addressed in this work were whether and how adaptation to suppression of visual information occurs in a free-fall paradigm, and the extent to which vision availability influences the control of landing movements. The prelanding modulation of EMG timing and amplitude of four lower-limb muscles was investigated. Participants performed six consecutive drop-landings from four different heights in two experimental conditions: with and without vision. Experimental design precluded participants from estimating the height of the drop. Since cues provided by proprioceptive and vestibular information acquired during the first trials were processed, the nervous system rapidly adapted to the lack of visual information, and hence produced a motor output (i.e., prelanding EMG modulation) similar to that observed when performing the activity with vision available.

Effects of Long-Term Blindness on Preparatory EMG Modulation in Humans Performing Landing Movements

To investigate the long-term effect of blindness on the task of leaping down to a lower landing surface, five blind individuals were compared with 10 sighted individuals who performed landing movements with and without sight. Participants performed six consecutive drop-landings from four different heights, during which the prelanding modulation of EMG timing and amplitude in four lower-limb muscles were recorded. Analysis showed that blind individuals showed specific prelanding EMG modulation, suggesting that long-term dependence on somesthetic and vestibular cues leads to different preparatory measures for vertical falls.

Quantificação do equilíbrio pelo videogame: estudo piloto

generation video games (VG) propose various balancing tests to asses stability of the user. However, the parameters used to provide the score of these tests are not reported in the literature, as well as their relation to clinical practice and user functionality. Objective: The objective of this study was to correlate the scores obtained by balancing tests of VG with kinetic variables provided by a force platform in simultaneous measurements. Method: This pilot study included two subjects with stroke and two with traumatic brain injury. Kinetic variables acquired were: area, velocity and root mean square of center of pressure position in the medial-lateral and anterior-posterior directions. Kinetic variables have been processed in Matlab 7.0® and correlated with the score provided by the console (balancing tests: Single-leg test -SL- and Steadiness test - ST -) using the Pearson correlation coefficient with p < 0.05. Results: A moderate correlation was found between the SL score and RMSy (r = 0.5839). When comparing the ST score to the variables: area (r = 0.8164), RMSx (r = -0.6418) and RMSy (r = -0.8094) the correlation was moderate to strong. Conclusion: No correlation was found with none of the tests of the console when compared with the velocity of displacement of the center of pressure measured on the force platform. It is concluded that the score of VG presented significant correlation with kinetic variables, but the method is impractical for being employed in clinical evaluation.Seventh generation video games (VG) propose various balancing tests to asses the stability of the user. However, the parameters used to provide the score of these tests are not reported in the literature, nor is their relationship to clinical practice and user functionality. Objective: The objective of this study was to correlate the scores obtained by the balance platform of the Wii video game with kinetic variables provided by a force platform in simultaneous measurements. Methods: This pilot study included two subjects with stroke and two with traumatic brain injury. The kinetic variables analyzed were: area, movement speed, and root mean square of center of pressure (COP) position in the medial-lateral and anterior-posterior directions, and were processed in Matlab 7.0® and correlated with the score provided by the console (balancing tests: Single-leg test - SL - and Steadiness test - ST -) using the Pearson and Spearman correlation coefficients, both with p < 0.05. Results: A moderate correlation was found between the SL score and RMSy (r = 0.5839). When comparing the ST score to the variables: area (r = 0.8164), RMSx (r = -0.6418) and RMSy (r = -0.8094) the correlation was moderate to strong. Conclusion: No correlation was found between the console tests and the movement speed of the center of pressure measured on the force platform. It is concluded that the score of VG presented significant correlation with the kinetic variables, but the method is not practical for being employed in a clinical evaluation.

No. 70 Mechanical Work as a Tool for the Assessment of Muscle Synergism

When a person performs a task, there is a displacement of the center of mass (COM) an action that consumes energy and performs mechanical work. The objective of this study was to quantify muscle synergism (MS) during maintenance of posture control using total mechanical work (WTOT) obtained from body segments after motor and visual disturbance. Ten healthy male subjects mean age 25.6 ( 226 ) years were selected to participate in this study. The subjects were asked to perform trunk extension to straight position in their maximum speed under the conditions: eyes open (EO) and eyes blindfolded (EB) in order to induce some motor and visual disturbance. Data were obtained from kinematic analysis using a frequency of 200 Hz and processed by Matlab software. Statistical analysis was performed using the Student’s t test for paired data (p > 0.05). There was a significant difference (p < 005) for legs at 0.60 MS and for thighs at 0.100 MS when both conditions (EO and EB) were compared. These differences may be related to somato-sensory mechanisms promoted by MS therefore suggesting that WTOT may be an invaluable tool to evaluate patients in physical rehabilitation programs.

Análise do controle postural após a aplicação da eletroestimulação funcional no acidente vascular encefálico

Strokes cause the main neurological impairments in adults around the world. They can result in neuromotor and cognitive deficits. Among the neuromotor deficits there is spasticity; this affects the planning of movements and posture control. The postural control system is essential for functional independence in daily life activities and is, therefore, one of the main goals to achieve in rehabilitation programs. These programs have various therapeutic elements aimed at providing stimulus to the individual, which help them control their movements and stance more efficiently. Among these techniques is neuromuscular electrical stimulation, which contributes to decreasing spasticity and other benefits. When used for functional tasks it is called Functional Electrical Stimulation (FES). Objective: The purpose of this study was to verify the response of the postural control in two individuals with hemiparesis by stroke after the application of the FES over a short period time. Method: The experimental protocol had four phases. A: pre-FES; B: Immediately after the application of FES; C: 45 minutes after the application of FES; D: 90 minutes after application of FES. In each phase, the participants were positioned on a force platform and made three attempts to do the chosen task: touching the fingertip-to-floor test. Results: The software Matlab 7.0 provided the variable center-of-pressure velocities along the mediolateral (Vmx) and anteroposterior (Vmy) axes. In this way it was possible to see that, even when the participants showed a reduction in Vmx and Vmy, it was by less than 1%. Conclusion: This may indicate postural regulatory activity similar to before the application of FES, and even less postural regulatory activity when the centerof-pressure velocities were greater at the start, even 90 minutes after the application of FES.O Acidente Vascular Encefalico (AVE) e o principal acometimento neurologico em adultos no mundo. Pode resultar em deficits neuromotores e cognitivos. Entre os deficits neuromotores observase a espasticidade, esta interfere no planejamento dos movimentos e no controle da postura. O sistema de controle da postura e primordial para a independencia funcional nas atividades de vida diaria e, por isso, e um dos principais objetivos a se atingir em programas de reabilitacao. Nestes, diversas condutas terapeuticas visam dar estimulos ao individuo para que consiga realizar mais eficientemente os movimentos e controlar a postura. E, entre tantas tecnicas, esta a estimulacao eletrica neuromuscular, a qual contribui para diminuicao da espasticidade, alem de outros beneficios. Quando utilizada para tarefas funcionais e entao denominada estimulacao eletrica funcional conhecida como Functional Eletrical Stimulation (FES). Tendo em vista a importância do controle da postura nas atividades de vida diaria e as contribuicoes advindas da FES. Objetivo: O objetivo do presente estudo foi de observar a resposta do controle postural em dois individuos com hemiparesia por AVE apos a aplicacao de FES em um curto periodo de tempo. Metodo: O protocolo experimental contou com quatro fases; A: pre FES; B: Imediatamente apos a aplicacao da FES; C: 45 minutos apos a aplicacao da FES; D: 90 minutos apos aplicacao da FES. Em cada fase o participante posicionava-se sobre uma plataforma de forca e realizava por tres tentativas a tarefa escolhida, o teste do terceiro dedo ao chao. Resultados: O software Matlab 7.0 forneceu a variavel de Velocidade media do Centro de Pressao no sentido medio-lateral (Vmx) e ântero-posterior (Vmy). Dessa forma, foi possivel constatar que mesmo quando os participantes apresentaram uma reducao na Vmx e Vmy estas foram menores que 1%. Conclusao: Isto possivelmente indique atividade regulatoria postural semelhante a etapa pre FES, e, ainda uma menor atividade regulatoria postural, quando a Vmx ou Vmy foram maiores que do inicio, mesmo apos a aplicacao da FES (90 minutos).

The effect of Functional Electric Stimulation in stroke patients' motor control – a case report

Functional Electric Stimulation (FES) has been studied as a therapeutic resource to reduce spasticity in hemiplegic patients, however there are no studies about the effects of FES in motor control of these patients during functional tasks like balance maintenance. Muscular activation of gastrocnemius medialis and semitendinosus was investigated in both limbs of a hemiparetic patient during self-disturbed quiet stance before and after FES on tibialis anterior, by surface electromyography. The instant of maximum activation peak of GM and ST were calculated immediately after a motor self-disturbance, in order to observe muscular synergy between these two muscles, and possible balance strategies used (ankle or hip strategy). At the preserved limb there occurred distal-proximal synergy (GM followed by ST), expected for small perturbations; however, at spastic limb there was inversion of this synergy (proximal-distal) after FES. It is possible that intervention of electricity had inhibited synergical pathways due to antidromic effect, making it difficult to use ankle strategy in the spastic limb.