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Motor synergies, i.e., neural mechanisms that organize multiple motor elements to ensure stability of actions, are affected by several neurological condition. Asymptomatic welders showed impaired synergy controlling the stability of multi-finger action compared to non-welders and this impairment was associated with microstructural damage in the globus pallidus. We further explored the effect of welding-related metal exposure on multi-finger synergy and extended our investigation to posture-stabilizing synergy during a standing task. Occupational, MRI, and performance-stabilizing synergies during multi-finger accurate force production and load releasing while standing were obtained from 29 welders and 19 age- and sex-matched controls. R2* and R1 relaxation rate values were used to estimate brain iron and manganese content, respectively, and diffusion tensor imaging was used to reflect brain microstructural integrity. Associations of brain MRI (caudate, putamen, globus pallidus, and red nucleus), and motor synergy were explored by group status. The results revealed that welders had higher R2* values in the caudate (p = 0.03), putamen (p = 0.01), and red nucleus (p = 0.08, trend) than controls. No group effect was revealed on multi-finger synergy index during steady-state phase of action (ΔVZss). Compared to controls, welders exhibited lower ΔVZss (-0.106 ± 0.084 vs. 0.160 ± 0.092, p = 0.04) and variance that did not affect the performance variable (VUCM, 0.022 ± 0.003 vs. 0.038 ± 0.007, p = 0.03) in the load releasing, postural task. The postural synergy index, ΔVZss, was associated negatively with higher R2* in the red nucleus in welders (r = -0.44, p = 0.03), but not in controls. These results suggest that the synergy index in the load releasing during a standing task may reflect welding-related neurotoxicity in workers with chronic metals exposure. This finding may have important clinical and occupational health implications.

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The postural control is improved by implicit somatosensory information from lightly touching a rigid bar or explicit visual information about the postural sway. Whether these two additional sources provided at the same time further reduce the postural sway is still unknown. Participants stood on a force plate as quiet as possible lightly touching the bar while received or not visual feedback of the center of pressure position on a monitor screen. Postural sway reduced similarly with the light touch regardless of the additional visual feedback. The findings suggested that providing explicit visual feedback of the center of pressure does not increase the light touch effects on the postural sway. The importance of the implicit somatosensory information on postural control is discussed.

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Introduction: Postural alignment has been studied by health professionals over the years. Due to technological advances, the use of quantitative methods for postural evaluation became more common in clinical practice. Objectives: To present different methods of postural assessment used by health professionals in the last decade. Methods: A literature review in the databases Lilacs, Medline, Pubmed, Cochrane and CAPES from 2000 to 2012 was made, in English, Spanish and Portuguese languages, and the following descriptors were used: posture, evaluation, motor activity, equipment, supplies, avaliación, actividad motora, equipos e suministros. Results: We found 33 papers published in refereed journals, however, only 25 references used qualitative or quantitative instruments for postural evaluation. Conclusion: In the past few years the use of softwares for quantitative postural assessment has been frequently adopted in clinical practice, in addition to the qualitative method. The adoption of these technological tools will allow health professionals to develop more accurate evaluations to determine the magnitude of postural changes. (AU)

Introdução: O alinhamento postural tem sido objeto de estudo de profissionais da saúde ao longo dos anos. Graças aos avanços tecnológicos, o uso de métodos quantitativos para avaliação da postura tem se tornado mais frequente na prática clínica.Objetivos: Apresentar os diferentes métodos de avaliação postural adotados por profissionais da saúde na última década. Métodos: Realizou-se uma revisão de literatura de artigos nas bases de dados Lilacs, Medline, Pubmed, Cochrane e CAPES, no período entre 2000 e 2012, nos idiomas inglês, espanhol e português, utilizando-se os seguintes descritores: postura, avaliação, atividade motora, equipamentos, provisões, posture, evaluation, motor activity, equipment, suplies, avaliación, actividad motora, equipos e suministros. Resultados: Foram encontrados 33 artigos científicos publicados em revistas indexadas, porém somente 25 referências utilizaram instrumentos qualitativos ou quantitativos de avaliação postural. Conclusão: Nos últimos anos o uso de softwares para realização de avaliação postural quantitativa tem se mostrado cada vez mais frequente na prática clínica, como complemento ao método qualitativo. A adoção dessas ferramentas tecnológicas permitirá ao profissional da saúde desenvolver avaliações mais acuradas e determinar a magnitude das alterações posturais. (AU)

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