RESUMO
Nonlinear analyses have emerged as an approach to unraveling the intricate dynamics and underlying mechanisms of postural control, offering insights into the complex interplay of physiological and biomechanical factors. However, achieving a comprehensive understanding of the application of nonlinear analysis in postural control studies remains a challenge due to the various nonlinear measurement methods currently available. Thus, this scoping review aimed to identify existing nonlinear analyses used to study postural control in both dynamic and quiet tasks, and to summarize and disseminate the available literature on the use of nonlinear analysis in postural control. For this purpose, a scoping review was conducted and reported following the PRISMA Extension for Scoping Reviews (PRISMA-ScR) Checklist and Explanation. Searches were conducted up to July 2023 on PubMed/Medline, Embase, CINAHL, Web of Science, and Google Scholar databases, resulting in the inclusion of 397 unique studies. The main classes employed among the studies were entropy-based, fractal-based, quantification of recurrence plots, and quantification of stability, with a total of 91 different algorithms distributed among these classes. The most common condition used to study postural control was quiet standing, followed by dynamic standing and gait tasks. Although various algorithms were utilized for this purpose, sample entropy was employed in 43% of studies to explore mechanisms related to postural control. Among them, 28% were in quiet standing, 3.27% were in dynamic standing, and 4.78% to study postural control during the gait. The results also provide insights into nonlinear analysis for future studies, concerning the complexity and interactions within the postural control system across various task demands.
RESUMO
Bone loss occurs rapidly and consistently after the occurrence of a spinal cord injury (SCI), leading to a decrease in bone mineral density (BMD) and a higher risk of fractures. In this context, the stimulatory effects of low level laser therapy (LLLT) also known as photobiomodulation (PBM) have been highlighted, mainly due to its osteogenic potential. The aim of the present study was to evaluate the effects of LLLT on bone healing using an experimental model of tibial bone defect in SCI rats. Twenty-four female Wistar rats were randomly divided into 3 groups: Sham group (SG), SCI control group (SC) and SCI laser treated group (SL). Two weeks after the induction of the SCI, animals were submitted to surgery to induce a tibial bone defect. Treatment was performed 3days a week, for 2weeks, at a single point over the area of the injury, using an 808nm laser (30mW, 100J/cm(2); 0.028cm(2), 1.7W/cm², 2.8J). The results of the histological and morphometric evaluation demonstrated that the SL group showed a larger amount of newly formed bone compared to the SC group. Moreover, a significant immunoexpression of runt-related transcription factor 2 (RUNX2) was observed in the SL group. There was no statistical difference in the biomechanical evaluation. In conclusion, the results suggest that LLLT accelerated the process of bone repair in rats with complete SCI.
