Vibration-induced postural reactions: a scoping review on parameters and populations studied

ObjectiveMechanical vibration is an effective way for externally activating Ia primary endings of the muscle spindles and skin mechanoreceptors. Despite its popularity in proprioception and postural control studies, there is still no review covering the wide variety of vibration parameters or locations used in studies. The main purpose of this scoping review was thus to give an overview of general vibration parameters and to identify, if available, the rationale for justifying methodological choices concerning vibration parameters.MethodsThree databases (Pubmed, CINHAL, and SPORTDiscus) were searched from inception to July 2022. Included articles were to focus on the study of muscle spindles and skin mechanoreceptors vibration in humans and assess postural control. Following inclusion, data regarding demographic information, populations, vibration parameters and rationale were extracted and summarized.ResultsOne hundred forty-seven articles were included, mostly targeting lower extremities (n = 137) and adults (n = 126). The parameters used varied widely but were most often around 80 Hz, at an amplitude of 1 mm for 10–20 s. Regarding rationales, nearly 50% of the studies did not include any, whereas those including one mainly cited the same two studies, without elaborating specifically on the parameter's choice.ConclusionThis scoping review provided a comprehensive description of the population recruited and parameters used for vibration protocols in current studies with humans. Despite many studies, there remain important gaps of knowledge that needs to be filled, especially for vibration amplitude and duration parameters in various populations

The Impact of Pain on Functionality, Postural Control and Fall Risk in Woman Aged 45 to 64 Years Old

Background: Ageing in women is associated with chronic degenerative pain leading to a functional decrease and therefore increase fall risk. It is therefore essential to detect early functional decreases in the presence of pain related to osteoarthritis. Objective: This cross-sectional study aimed to assess the impact of pain on functionality, postural control and fall risk in women aged between 45 to 64 years old. Methods: Twenty-one (21) women aged 45 to 64 were evaluated by clinical and functional measures such as a pain questionnaire (Lequesne Index), functional tests (Stair Step Test, 5 times sit-to-stand, 6MWD, Timed-up and Go) and postural performance (under force platform). Women were classified into 2 groups from the Lequesne Pain Index (PI): low pain (score ≤ 9) and strong pain (score ≥ 10) for subsequent comparisons on functionality (physical and postural control performance). Results: A significant impact was observed between the pain index (strong PI) and 3 of the 4 functional tests carried out including Stair Step Test (p = 0.001; g = 1.44), walking distance (p = 0.003; g = 1.31) and Timed-up and Go (p = 0.04; g = −0.93). The group with a strong PI score reported further poor postural control under force platform compared to the weak pain group. Conclusion: Pain and severity based on the PI index negatively modulate physical and postural control performance in women aged 45 to 64 years old

Immediate effect of bilateral talocrural joint manipulation on postural balance in healthy subjects

The aim of this study was to assess the immediate effect of bilateral talocrural joint manipulation on the postural balance of healthy subjects. Ninety healthy subjects (21 males and 69 females) were included in this study. The mean age, height and body weight of the subjects were 22.21 years, 165.1 cm and 62.58 Kg, respectively. Following collection of anthropometric data, the subjects were allocated randomly into an experimental group (receiving real talocrural joint manipulation), a placebo group and a control group. Before and after manipulation, the subjects performed two postural balance tasks, inquiet standing position (eyes open and eyes closed) on a force platform. The stabilometric data were recorded for 60 seconds in each condition. Sway area, medio-lateral (ML) and anteroposterior (AP) velocities and median frequency were calculated from the center of pressure (COP) displacements. The results showed that in the experimental group the COP sway velocity decreased in both directions of movement (AP and ML) and in both visual tasks (eyes open and eyes closed). In general, the placebo and control groups had similar postural balance across balance parameterss. Significant effect of the bilateral talocrural joint manipulation was found on main balance parameter like COP velocity in the anteroposterior and mediolateral directions. These results have some much implications for manual therapy rehabilitation of individuals with ankle instability

A rational experimental approach to identify correctly the working voltage window of aqueous-based supercapacitors

It is common to find in the literature different values for the working voltage window (WVW) range for aqueous-based supercapacitors. In many cases, even with the best intentions of the widening the operating voltage window, the measured current using the cyclic voltammetry (CV) technique includes a significant contribution from the irreversible Faradaic reactions involved in the water-splitting process, masked by fast scan rates. Sometimes even using low scan rates is hard to determine precisely the correct WVW of the aqueous-based electrochemical capacitor. In this sense, we discuss here the best practices to determine the WVW for capacitive current in an absence of water splitting using complementary techniques such as CV, chronoamperometry (CA), and the electrochemical impedance spectroscopy (EIS). To accomplish this end, we prepare and present a model system composed of multiwalled carbon nanotubes buckypaper electrodes housed in the symmetric coin cell and soaked with an aqueous-based electrolyte. The system electrochemical characteristics are carefully evaluated during the progressive enlargement of the cell voltage window. The presence of residual Faradaic current is verified in the transients from the CA study, as well as the impedance changes revealed by EIS as a function of the applied voltage, is discussed. We verify that an apparent voltage window of 2.0 V determined using the CV technique is drastically decreased to 1.2 V after a close inspection of the CA findings used to discriminate the presence of a parasitic Faradaic process. Some orientations are presented to instigate the establishment in the literature of some good scientific practices concerned with the reliable characterization of supercapacitors10CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP310544/2019-0; 301095/2018-32014/02163-7; 2017/11958-1; 2018/20756-

Role of cGMP and cAMP in the hemodynamic response to intrathecal sildenafil administration

INTRODUCTION: Results from our laboratory have demonstrated that intracerebroventricular administration of sildenafil to conscious rats promoted a noticeable increase in both lumbar sympathetic activity and heart rate, with no change in the mean arterial pressure. The intracerebroventricular administration of sildenafil may have produced the hemodynamic effects by activating sympathetic preganglionic neurons in the supraspinal regions and spinal cord. It is well documented that sildenafil increases intracellular cGMP levels by inhibiting phosphodiesterase type 5 and increases cAMP levels by inhibiting other phosphodiesterases. OBJECTIVE: To examine and compare, in conscious rats, the hemodynamic response following the intrathecal administration of sildenafil, 8-bromo-cGMP (an analog of cGMP), forskolin (an activator of adenylate cyclase), or dibutyryl-cAMP (an analog of cAMP) in order to elucidate the possible role of the sympathetic preganglionic neurons in the observed hemodynamic response. RESULTS: The hemodynamic responses observed following intrathecal administration of the studied drugs demonstrated the following: 1) sildenafil increased the mean arterial pressure and heart rate in a dose-dependent manner, 2) increasing doses of 8-bromo-cGMP did not alter the mean arterial pressure and heart rate, 3) forskolin did not affect the mean arterial pressure but did increase the heart rate and 4) dibutyryl-cAMP increased the mean arterial pressure and heart rate, similar to the effect observed following the intrathecal injection of the highest dose of sildenafil. CONCLUSION: Overall, the findings of the current study suggest that the cardiovascular response following the intrathecal administration of sildenafil to conscious rats involves the inhibition of phosphodiesterases other than phosphodiesterase type 5 that increase the cAMP level and the activation of sympathetic preganglionic neurons

Comparação da prova de função pulmonar e da força muscular respiratória entre idosas osteoporóticas com e sem fratura vertebral torácica = Comparation of pulmonary function and respiratory muscle strength among older osteoporotic women with and without thoracic vertebral fracture

Introduction: Osteoporosis is a disease characterized by decreased bone mass, resulting in fractures, which may occur in the thoracic vertebrae, causing changes in respiratory mechanics, impairing lung function. Objectives: To compare the spirometric, respiratory muscle strength and angle of thoracic kyphosis among elderly osteoporotic vertebral fractures with and without chest. Methods: The sample was divided into group A, elderly women with thoracic vertebral fracture (n = 5) and group B, older chest without vertebral fracture (n = 7). All were assessed by spirometry, manometer, and anthropometric measurements of the thoracic curvature. Results: The results showed an increase in thoracic curvature and a decrease in lung function in Group A compared with Group B and respiratory muscle strength deficit in Group A. Conclusion: The thoracic kyphosis deformity, caused by osteoporotic fractures, affects both the respiratory and musculoskeletal system

Analysis of bond strength between a nylon reinforcement structure and dental resins

Nylon is a polymer that its use to reinforce dental resins has shown positive results such as increased flexural strength. The aim of this study was to evaluate the bond strength between dental resins and a nylon reinforcement. Forty cylindrical nylon

Towards the Objective Identification of the Presence of Pain Based on Electroencephalography Signals’ Analysis: A Proof-of-Concept

This proof-of-concept study explores the potential of developing objective pain identification based on the analysis of electroencephalography (EEG) signals. Data were collected from participants living with chronic fibromyalgia pain (n = 4) and from healthy volunteers (n = 7) submitted to experimental pain by the application of capsaicin cream (1%) on the right upper trapezius. This data collection was conducted in two parts: (1) baseline measures including pain intensity and EEG signals, with the participant at rest; (2) active measures collected under the execution of a visuo-motor task, including EEG signals and the task performance index. The main measure for the objective identification of the presence of pain was the coefficient of variation of the upper envelope (CVUE) of the EEG signal from left fronto-central (FC5) and left temporal (T7) electrodes, in alpha (8–12 Hz), beta (12–30 Hz) and gamma (30–43 Hz) frequency bands. The task performance index was also calculated. CVUE (%) was compared between groups: those with chronic fibromyalgia pain, healthy volunteers with “No pain” and healthy volunteers with experimentally-induced pain. The identification of the presence of pain was determined by an increased CVUE in beta (CVUEβ) from the EEG signals captured at the left FC5 electrode. More specifically, CVUEβ increased up to 20% in the pain condition at rest. In addition, no correlation was found between CVUEβ and pain intensity or the task performance index. These results support the objective identification of the presence of pain based on the quantification of the coefficient of variation of the upper envelope of the EEG signal