Influence of Gestational Age on Pelvic Floor Muscle Activity, Plantar Contact, and Functional Mobility in High-Risk Pregnant Women: A Cross-Sectional Study.

During pregnancy, biomechanical changes are observed due to hormonal and physical modifications, which can lead to alterations in the curvature of the spine, balance, gait patterns, and functionality of the pelvic floor muscles. This study aimed to investigate the progressive impact of biomechanical changes that occur during gestational weeks on the myoelectric activity of the pelvic floor muscles, plantar contact area, and functional mobility of high-risk pregnant women. METHODS: This was a cross-sectional observational study carried out from November 2022 to March 2023. A total of 62 pregnant women of different gestational ages with high-risk pregnancies were analyzed using surface electromyography to assess the functionality of the pelvic floor muscles, plantigraphy (Staheli index and plantar contact area), and an accelerometer and gyroscope using the timed up and go test via an inertial sensor on a smartphone. Descriptive statistics and multivariate linear regression analyses were carried out to test the predictive value of the signature. RESULTS: Increasing weeks of gestation resulted in a decrease in the RMS value (ß = -0.306; t = -2.284; p = 0.026) according to the surface electromyography analyses. However, there was no association with plantar contact (F (4.50) = 0.697; p = 0.598; R2 = 0.53). With regard to functional mobility, increasing weeks of gestation resulted in a decrease in time to standing (ß = -0.613; t = -2.495; p = 0.016), time to go (ß = -0.513; t = -2.264; p = 0.028), and first gyrus peak (ß = -0.290; t = -2.168; p = 0.035). However, there was an increase in the time to come back (ß = 0.453; t = 2.321; p = 0.025) as the number of gestational weeks increased. CONCLUSIONS: Increased gestational age is associated with a reduction in pelvic floor myoelectric activity. The plantar contact area did not change over the weeks. Advancing gestation was accompanied by a decrease in time to standing, time to go, and first gyrus peak, as well as an increase in time to come back.

Accelerometer approach for anticipatory postural adjustments assessment during step initiation in patients with leprosy.

Anticipatory postural adjustments (APAs) involve a complex coordination of sensorimotor information that can be impaired in diseases that affect nerve conduction. Assessing APAs typically requires costly video recording technology, posing a challenge to the study of postural changes. This hurdle is compounded in impoverished communities affected by diseases such as leprosy, which often receive limited government support. Recent years have seen the validation of inertial sensors in wearable devices and smartphones for APA analysis in diverse populations, including adults, the elderly and people with Parkinson's disease. This progress offers economically efficient alternatives for the study of APA in leprosy. Do patterns of activation of anticipatory postural adjustment differ between leprosy patients and healthy controls? We also investigated the validity and replicability of APAs recorded in leprosy patients using inertial measurements and video capture recordings. Thirty healthy individuals in the control group and 30 individuals with leprosy in the leprosy group performed ten gait initiation trials. To record the APA for gait initiation, the participants stood on a 2 m platform. Each participant was informed that the experimenter would give an signal, after which the participant would initiate a two-step walk on the platform. Inertial recordings (low-cost method) and video capture recordings (gold-standard method) from center of mass displacements were used to extract the APA before gait initiation. The results show that APAs are similar between groups (control and leprosy), but leprosy patients have less consistent APAs. In addition, this study highlights the reproducibility and high correlation between the values of variables obtained from both instruments, the video recording as gold standard method and portable digital inertial sensor as a low-cost alternative method. These promising findings support the use of affordable inertial sensors to track and record APAs in underserved populations that lack easy access to gold standard methods such as video recording. This approach has the potential to improve the therapeutic care and rehabilitation of these patients. Although not currently part of official protocols for leprosy patients, this assessment method could prove particularly valuable in situations where significant sensorimotor impairments are suspected or documented.

Smartphone-based evaluation of static balance and mobility in type 2 Diabetes.

It was compared smartphone-based measurements of static balance control and mobility of elderly population with and without type 2 diabetes mellitus (DM2). The present cross-sectional study investigated 73 participants grouped in a control group (n = 36) and a DM2 group (n = 37). Smartphone's built in inertial sensors were used to record inertial changes of the participants during static balance and mobility (Timed Up and Go test - TUG) tasks. The inertial variations as a function of the time were analyzed and compared between groups. Both groups were matched in age, body mass index, male-female proportion, but DM2 group had significant larger fasting glucose than control group. Additionally, DM2 group had worst static balance control with open and closed eyes than the controls (p < 0.05) as well as they also had longer duration to execute the different events of the mobility test than the controls (p < 0.05). DM2 patients had decline of motor functions compared to controls and the use of bult-in sensors of smartphones was feasible to identify these functional impairments. The easy access of smartphones could be improving the screening of functional impairments in DM2 patients.

Enhancing public health in developing nations through smartphone-based motor assessment.

Several protocols for motor assessment have been validated for use on smartphones and could be employed by public healthcare systems to monitor motor functional losses in populations, particularly those with lower income levels. In addition to being cost-effective and widely distributed across populations of varying income levels, the use of smartphones in motor assessment offers a range of advantages that could be leveraged by governments, especially in developing and poorer countries. Some topics related to potential interventions should be considered by healthcare managers before initiating the implementation of such a digital intervention.

Effectiveness assessment of a home-based exercise intervention in mitigating HTLV-1 associated disabilities: A validation study.

To evaluate the effectiveness of a home exercise program called Home Exercise Booklet for People Living with Human T Lymphotropic Virus 1 (HTLV-1). This is a methodological study of content validation with expert judges. A questionnaire with a Likert scale was applied, containing 16 items referring to the content domain. Descriptive statistics were used to obtain the content validity index. In total, 46 judges participated, 24 physiotherapists (PG) and 22 professionals from other health areas specializing in methodological studies and HTLV-1 (EG). In the validation process, each evaluator judged the technology and scored their considerations. In the end, we obtained the following results for the Content Validity Index (CVI): PG CVI: 94.3%, GE CVI: 93.4%. Although the index was sufficient to consider the technology validated, modifications were made to the second and final version of the booklet, considering the judges' observations and suggestions, which we consider relevant. The technology proved to be valid for use with the target audience. The development and validation of this product provides support to help prevent functional decline in people living with HTLV-1; standardize guidelines for physiotherapy professionals who monitor these issues; start a home exercise program aimed at other comorbidities; open the possibility of creating and validating home exercise programs with other comorbidities.

Intra and Inter-Device Reliabilities of the Instrumented Timed-Up and Go Test Using Smartphones in Young Adult Population.

The Timed-Up and Go (TUG) test is widely utilized by healthcare professionals for assessing fall risk and mobility due to its practicality. Currently, test results are based solely on execution time, but integrating technological devices into the test can provide additional information to enhance result accuracy. This study aimed to assess the reliability of smartphone-based instrumented TUG (iTUG) parameters. We conducted evaluations of intra- and inter-device reliabilities, hypothesizing that iTUG parameters would be replicable across all experiments. A total of 30 individuals participated in Experiment A to assess intra-device reliability, while Experiment B involved 15 individuals to evaluate inter-device reliability. The smartphone was securely attached to participants' bodies at the lumbar spine level between the L3 and L5 vertebrae. In Experiment A, subjects performed the TUG test three times using the same device, with a 5 min interval between each trial. Experiment B required participants to perform three trials using different devices, with the same time interval between trials. Comparing stopwatch and smartphone measurements in Experiment A, no significant differences in test duration were found between the two devices. A perfect correlation and Bland-Altman analysis indicated good agreement between devices. Intra-device reliability analysis in Experiment A revealed significant reliability in nine out of eleven variables, with four variables showing excellent reliability and five showing moderate to high reliability. In Experiment B, inter-device reliability was observed among different smartphone devices, with nine out of eleven variables demonstrating significant reliability. Notable differences were found in angular velocity peak at the first and second turns between specific devices, emphasizing the importance of considering device variations in inertial measurements. Hence, smartphone inertial sensors present a valid, applicable, and feasible alternative for TUG assessment.

Electromyographic activity of pelvic floor muscles in different positions during the use an innovative vaginal educator: Cross-sectional study.

The pelvic floor requires an integrated anatomical structure owing to its multiple functions. Therefore, it is necessary to study methods for improving muscle recruitment during training. This study aimed to analyze the effect of using an innovative vaginal trainer on the bioelectrical activity of the pelvic floor muscles. Pelvic positioning and interference factors, such as age, childbirth, sexual activity, urinary incontinence, and menopause, were also analyzed. A cross-sectional study assessed 30 women using an evaluation form, International Consultation on Incontinence Questionnaire-Short Form, and surface electromyography. The root mean square of a 5-second contraction period, peak root mean square values, area values, % maximal voluntary contraction (root mean square normalized by peak signal), and median frequency were collected. These findings with and without the use of a vaginal educator were compared in the anteversion, neutral, and retroversion pelvic positions. The use of a vaginal educator was found to increase the electromyographic activity of the pelvic floor muscles in the neutral position. In this position, older women showed an increased peak contraction when using the educator. Multiparas also benefited from increased bioelectric activity (root mean square and area). Sexually active women increased their bioelectric activity in a neutral position when using the trainer, exerting less effort in retroversion (%-maximal voluntary contraction). Incontinent and menopausal women exhibited slower body-building activation (decreased frequency) with the device, which requires further investigation. Our innovative biofeedback device induced greater recruitment of muscle fibers, is more effective in the neutral pelvic position, and may be effective in training the pelvic floor muscles, even in women with a greater tendency toward pelvic floor dysfunction.

Virtual Reality in Improving Anticipatory Postural Adjustments to Step Initiation in Individuals with Knee Osteoarthritis: A Randomized Controlled Trial.

Background: Virtual reality (VR) has been suggested as a new therapeutic approach in various sectors of rehabilitation, including the treatment of patients with knee osteoarthritis (OA), and one of its treatment goals is to improve the gait pattern and walking ability of patients. Objective: This study aimed to evaluate if VR, along with conventional physiotherapy treatment (CT), has superior effects to kinesiotherapy alone on pain, physical capacity, balance, and the parameters of anticipatory postural adjustments (APAs) in patients with knee OA. Design: This study is a single-blind randomized controlled trial. Setting: Secondary care at Hospital SARAH Network of Rehabilitation Hospitals, Brazil. Participants: Forty participants (31 women and 9 men) with knee OA in at least one knee and able to ambulate independently. Intervention: A rehabilitation program (8 consecutive weeks, 50-minute session, twice a week). Patients were randomized into the intervention groups CT or VR. Main Outcome Measures: Primary-latency of APA, amplitude of APA, and time to reach the maximum acceleration amplitude. Secondary-balance control by Mini-Balance Evaluation Systems Test, pain, and physical capacity by Western Ontario and McMaster Universities Arthritis Index. Results: The results of the study showed that conventional treatment significantly improved pain intensity, physical capacity, and balance in individuals with knee OA; however, only the group that used VR showed improvement in the APA parameters. Conclusion: This study demonstrated that VR associated with conventional treatment improved APAs in patients with knee OA.

Smartphone-based inertial measurements during Chester step test as a predictor of length of hospital stay in abdominopelvic cancer postoperative period: a prospective cohort study.

BACKGROUND: Objective assessment of pre-operative functional capacity in cancer patients using the smartphone gyroscope during the Chester step (CST) test may allow greater sensitivity of test results. This study has investigated whether the CST is a postoperative hospital permanence predictor in cancer patients undergoing abdominopelvic surgery through work, VO2MAX and gyroscopic movement analysis. METHODS: Prospective, quantitative, descriptive and inferential observational cohort study. Fifty-one patients were evaluated using CST in conjunction with a smartphone gyroscope. Multivariate linear regression analysis was used to examine the predictive value of the CST. RESULTS: The duration of hospital permanence 30 days after surgery was longer when patients who performed stage 1 showed lower RMS amplitude and higher peak power. The work increased as the test progressed in stage 3. High VO2MAX seemed to be a predictor of hospital permanence in those who completed levels 3 and 4 of the test. CONCLUSION: The use of the gyroscope was more accurate in detecting mobility changes, which predicted a less favorable result for those who met at level 1 of the CST. VO2MAX was a predictor of prolonged hospitalization from level 3 of the test. The work was less accurate to determine the patient's true functional capacity.

Plantar pressure distribution and altered postural control in multibacillary leprosy patients.

BACKGROUND: Leprosy is a chronic infectious disease caused by Mycobacterium leprae, predominantly affecting the peripheral nerves, resulting in sensory and motor deficits in the feet. Foot ulcers and imbalances are frequent manifestations in leprosy, often correlating with diminished sensitivity. While clinical scales and monofilament esthesiometers are conventionally utilized to evaluate foot sensitivity and balance in these patients, their discriminatory power is limited and their effectiveness is greatly dependent on the examiner's proficiency. In contrast, baropodometry and posturography offer a more comprehensive evaluation, aiming to preempt potential damage events. This study aimed was to assess the correlation between baropodometry and force plate measurements in leprosy patients and control participants, to improve the prevention and treatment of foot ulcers and complications associated with leprosy. METHODOLOGY: This cross-sectional study was conducted during 2022 and enrolled 39 participants (22 patients with multibacillary leprosy and 17 non-leprosy controls). Demographic data were collected, and a monofilament esthesiometer was used to assess sensory deficits. In addition, physical examinations and balance and plantar pressure tests were conducted. The Student's t-test was used to compare mean and maximum plantar pressures between groups. For most COP variables, a Mann-Whitney Wilcoxon test was used, except for AP amplitude which was analyzed with the Student's t-test due to its normal distribution. The relationship between foot pressure and balance control was assessed using Spearman's correlation, focusing on areas with significant pressure differences between groups. PRINCIPAL FINDINGS: Leprosy patients showed increased pressure in forefoot areas (T1, M1, T2-T5, and M2) and decreased pressure in hindfoot regions (MH and LH) compared to controls. These patients also displayed higher AP and ML amplitudes, suggesting poorer COP control. Correlation analyses between the two groups revealed that foot plantar pressures significantly impact balance control. Specifically, increased T1 region pressures correlated with greater sway in balance tasks, while decreased MH region pressures were linked to reduced COP control. CONCLUSIONS/SIGNIFICANCE: The findings suggest a joint disturbance of plantar pressure distribution and static balance control in leprosy patients. These alterations may increase the risk of tissue injuries, including calluses and deformities, as well as falls.

Smartphone-based evaluation of static balance and mobility in long-lasting COVID-19 patients.

Background: SARS-CoV-2 infection can lead to a variety of persistent sequelae, collectively known as long COVID-19. Deficits in postural balance have been reported in patients several months after COVID-19 infection. The purpose of this study was to evaluate the static balance and balance of individuals with long COVID-19 using inertial sensors in smartphones. Methods: A total of 73 participants were included in this study, of which 41 had long COVID-19 and 32 served as controls. All participants in the long COVID-19 group reported physical complaints for at least 7 months after SARS-CoV-2 infection. Participants were evaluated using a built-in inertial sensor of a smartphone attached to the low back, which recorded inertial signals during a static balance and mobility task (timed up and go test). The parameters of static balance and mobility obtained from both groups were compared. Results: The groups were matched for age and BMI. Of the 41 participants in the long COVID-19 group, 22 reported balance impairment and 33 had impaired balance in the Sharpened Romberg test. Static balance assessment revealed that the long COVID-19 group had greater postural instability with both eyes open and closed than the control group. In the TUG test, the long COVID-19 group showed greater acceleration during the sit-to-stand transition compared to the control group. Conclusion: The smartphone was feasible to identify losses in the balance motor control and mobility of patients with long-lasting symptomatic COVID-19 even after several months or years. Attention to the balance impairment experienced by these patients could help prevent falls and improve their quality of life, and the use of the smartphone can expand this monitoring for a broader population.

Physiotherapy Methods Applied in the Prevention of Functional Loss Associated with Human T-Lymphotropic Virus 1 Infection: An Overview.

To achieve the objective of this study, we conducted a narrative review on physical therapeutic modalities applied to prevent functional losses associated with human T-lymphotropic virus 1 (HTLV-1) infections to promote health education and viable and accessible alternatives in the development of health education technology adapted to the home environment. This study comprised a qualitative stage of theoretical development to construct a digital booklet with an observational basis based on studies that reiterate themes about educational technologies as tools to conduct a home protocol of guided exercises without the direct supervision of professional physical therapists. Results indicate a lack of research on the development of health education technologies to assist patients with HTLV-1 without tropical spastic paraparesis or HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We believe that this narrative review can initiate a theoretical framework to conduct a home exercise program aimed at people with HTLV-1 who have subtle symptoms, and also at people without the clinical definition of HAM/TSP, helping to train human resources for care and research on the subject and increase scientific production in physical therapy.

The role of sex and handedness in the performance of the smartphone-based Finger-Tapping Test.

The Finger Tapping Test (FTT) is a classical neuropsychological test that assesses motor functioning, and recently it has been employed using smartphones. For classical protocols, it has been observed that sex and handedness influence the performance during the test. By assessing the influence of sex and handedness on the test, it is possible to adjust the performance measurements to ensure the validity of test results and avoid sex- and handedness-related bias. The present study aimed to evaluate the influence of sex and handedness on smartphone-based FTT performance. We developed an Android application for the FTT and recruited 40 males and 40 females to carry out three spatial designs on it (protocols I, II, and III). Participants' performance was measured using the global, temporal, and spatial parameters of the FTT. We observed that for the performance in protocol I, handedness had a significant influence on global and temporal variables, while the interaction between handedness and sex had a greater influence on spatial variables. For protocols II and III, we observed that handedness had a significant influence on global, temporal, and spatial variables compared to the other factors. We concluded that the smartphone-based test is partly influenced by handedness and sex, and in clinical implications, these factors should be considered during the evaluation of the smartphone-based FTT.

Wearable-based assessment of anticipatory postural adjustments during step initiation in patients with knee osteoarthritis.

Older adults with moderate to severe knee osteoarthritis (KOA) exhibit adaptive strategy for initiating walking, known as anticipatory postural adjustments (APAs). While video motion kinematics has been the traditional way of measuring APAs, it can be difficult to transport and install, making it impractical for medical settings. Inertial sensors have become a more popular method for evaluating APAs, but no prior research has used accelerometers to measure gait initiation in individuals with KOA. The study aimed to assess the validity and reliability of a wearable accelerometer device for measuring APAs older adults with and without KOA. 25 individuals with KOA and 10 healthy individuals underwent evaluation using a wearable commercially available accelerometer (MetamotionC) and a video motion capture system. Reflective markers were placed on the lumbar vertebra and calcaneus. Participants were asked to initiate a step, and the researchers measured the APAlatency and APAamplitude of each subject. APAlatency showed an very large to almost perfect correlation in both groups (CG:r = 0.82; p = 0.003 and KOA r = 0.98; p < 0.00001) between the instruments, while APAamplitude had a moderate to very large correlation (CG: r = 0.65; p = 0.04and KOA: r = 0.80; p < 0.00001). Overall, the measurements showed fair to high reliability for intraclass correlation for video and accelerometer variables. Significant group effect was found for both variables: APAlatency (F1, 66 = 7.3; p = 0.008) and APAamplitude (F1,66 = 9.5; p = 0.00). The wearable tri-axial accelerometer is a valid and reliable for assessing APAs during gait initiation in individuals with KOA, and this population exhibits lower APAs when initiating a step.

Comparison of inertial records during anticipatory postural adjustments obtained with devices of different masses.

Background: Step initiation involves anticipatory postural adjustments (APAs) that can be measured using inertial measurement units (IMUs) such as accelerometers. However, previous research has shown heterogeneity in terms of the population studied, sensors used, and methods employed. Validity against gold standard measurements was only found in some studies, and the weight of the sensors varied from 10 to 110 g. The weight of the device is a crucial factor to consider when assessing APAs, as APAs exhibit significantly lower magnitudes and are characterized by discrete oscillations in acceleration paths. Objective: This study aims to validate the performance of a commercially available ultra-light sensor weighing only 5.6 g compared to a 168-g smartphone for measuring APAs during step initiation, using a video capture kinematics system as the gold standard. The hypothesis is that APA oscillation measurements obtained with the ultra-light sensor will exhibit greater similarity to those acquired using video capture than those obtained using a smartphone. Materials and Methods: Twenty subjects were evaluated using a commercial lightweight MetaMotionC accelerometer, a smartphone and a system of cameras-kinematics with a reflective marker on lumbar vertebrae. The subjects initiated 10 trials of gait after a randomized command from the experimenter and APA variables were extracted: APAonset, APAamp, PEAKtime. A repeated measures ANOVA with post-hoc test analyzed the effect of device on APA measurements. Bland-Altman plots were used to evaluate agreement between MetaMotionC, smartphone, and kinematics measurements. Pearson's correlation coefficients were used to assess device correlation. Percentage error was calculated for each inertial sensor against kinematics. A paired Student's t-test compared th devices percentage error. Results: The study found no significant difference in temporal variables APAonset and PEAKtime between MetaMotionC, smartphone, and kinematic instruments, but a significant difference for variable APAamp, with MetaMotionC yielding smaller measurements. The MetaMotionC had a near-perfect correlation with kinematic data in APAonset and APAamp, while the smartphone had a very large correlation in APAamp and a near-perfect correlation in APAonset and PEAKtime. Bland-Altman plots showed non-significant bias between smartphone and kinematics for all variables, while there was a significant bias between MetaMotionC and kinematics for APAamp. The percentage of relative error was not significantly different between the smartphone and MetaMotionC. Conclusions: The temporal analysis can be assessed using ultralight sensors and smartphones, as MetaMotionC and smartphone-based measurements have been found to be valid compared to kinematics. However, caution should be exercised when using ultralight sensors for amplitude measurements, as additional research is necessary to determine their effectiveness in this regard.

Anticipatory postural adjustments in older versus young adults: a systematic review and meta-analysis.

BACKGROUND: Anticipatory postural adjustments (APAs) are a feedforward mechanism triggered in advance to a predictable perturbation, to help the individual counteract mechanical effects that the disturbance may cause. Whether or not this strategy is compromised in the elderly is not a consensus in the literature. METHODS: In this systematic review with meta-analysis, we investigated aging effects on postural control, based on anticipatory postural adjustments (APAs). We selected 11 eligible articles of the following databases: Lilacs, SciELO, PubMed, Cochrane Central, Embase, and CINAHL, involving 324 research participants, assessing their methodological quality and extracting electromyographic, posturographic, and kinematic measurements. We included studies that investigated the occurrence of APAs in healthy younger and older adults, published before 10th August 2022, in English. Studies involving participant with conditions that may affect balance or that did not report measures of onset or amplitude of electromyography (EMG), COP, or kinematics were excluded. To analyze the aggregated results from these studies, we performed the analysis based on the outcome measures (EMG, COP, or kinematic measures) used in individual studies. We calculated differences between younger and older adult groups as the mean differences between the groups and the estimated effect. Egger's test was conducted to evaluate whether this meta-analysis had publication bias. RESULTS: Through this review, older adults showed no significant difference in the velocity to perform a movement compared to the younger adults (MD 0.95, 95% CI -0.86, 2.76, I2 = 82%), but both muscle onset and center of pressure (COP) onset were significantly more delayed in older than in younger adults: erector spinae (MD -31.44, 95% CI -61.79, -1.09, I2 = 95%); rectus abdominis (RA) (MD -31.51, 95% CI -70.58, -3.57, I2 = 85%); tibialis anterior (TA) (MD -44.70, 95% CI -94.30, 4.91, I2 = 63%); soleus (SOL) (MD -37.74, 95% CI -65.43, -10.05, I2 = 91%); gastrocnemius (GAS) (MD -120.59, 95% CI -206.70, -34.49, I2 = 94%); quadriceps (Q) (MD -17.42, 95% CI -34.73, -0.12, I2 = 0%); biceps femoris (BF) (MD -117.47, 95% CI -192.55, -42.70, I2 = 97%); COP onset (MD -45.28, 95% CI -89.57, -0.98, I2 = 93%), and COP apa (COPapa) (MD 2.35, 95% CI -0.09, 4.79, I2 = 64%). These changes did not seem to be linked to the speed of movement but possibly to age-related physiological changes that indicated decreased motor control during APAs in older adults. CONCLUSIONS: Older adults use different postural strategies that aim to increase the safety margin and stabilize the body to perform the movement, according to the requirements imposed, and this should be considered in rehabilitation protocols. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD420119143198.

Wearable Inertial Sensor Approach for Postural Adjustment Assessments during Predictable Perturbations in Sport.

INTRODUCTION: Evidence supports the importance of efficient postural control to improve performance in sports. This involves the use of strategies such as anticipatory posture adjustments and compensatory adjustments. Technology makes analysis and assessments in sports cheaper, while being valid and reliable compared to the gold-standard assessment equipment. OBJECTIVES: This article aimed to test the validity and reliability of signals extracted from the sensor's accelerometer (Metamotion C), by comparing it to the data obtained from the gold-standard equipment (a three-dimensional video-motion-capture system). DESIGN: Observational, cross-sectional study. METHODS: We exposed 20 healthy young standing people to the pendulum impact paradigm, which consisted of predictable anteroposterior disturbances applied at the shoulder level. In order to measure this, we observed the acceleration of the center of mass in the anticipatory and compensatory phase of the disturbance and compared the signals of the two devices (Metamotion C and a motion-capture system). RESULTS: The validation results showed the significant linear correlation of all variables with a moderate to large correlation of r ≥ 0.5 between the devices. In contrast, the reliability results between sessions obtained by filming were all significant and above 0.75, indicating excellent reliability. The APAonset variable had a reasonable to high intra-class correlation in the anticipatory phase. In the compensatory phase, the CPAtime variable showed an excellent correlation. CONCLUSIONS: Metamotion C proved reasonably valid and highly reliable in measuring the center of mass acceleration compared to the camera system in both the anticipatory and compensatory phases.

Comparison of Static Balance Control in Infected Htlv-1 Subjects with Different Tsp/Ham Diagnosis.

(1) Background: Tropical spastic paraparesis (TSP/HAM) associated with the T cell lymphotropic virus in type I humans (HTLV-1) is a slow, chronic, and progressive disease that causes balance changes. TSP/HAM diagnosis can be classified as probable, possible, and definite. We compared the static balance control of HTLV-1-infected patients with different TSP/HAM diagnosis. (2) Methods: Our sample consisted of 13 participants infected with HTLV-1 and 16 healthy participants. The center of pressure was recorded using a force platform with open and closed eyes. We divided the recordings into three intervals, period T1 (corresponds to the first 10 s); period T2 (from 10 to 45 s); period T3 (from 45 to 55 s). (3) Results: Eight participants infected with HTLV-1 were classified as probable TSP/HAM and five participants infected with HTLV-1 were classified as definite TSP/HAM. There was a significant increase in postural instability in patients with definite PET/MAH considering the structural and global variables of body sway compared to the control and the probable TSP/HAM. (4) Conclusions: We concluded that the severity of balance is directly related to the degree of signs and symptoms of TSP/HAM.

Postural Adjustments in HTLV-1 Infected Patients during a Self-Initiated Perturbation.

BACKGROUND: Human T-cell lymphotropic virus type 1 (HTLV-1) infection can be associated with tropical spastic paraparesis (TSP/HAM), which causes neurological myelopathy and sensory and muscle tone alterations, leading to gait and balance impairments. Once trunk perturbation is predicted, the motor control system uses anticipatory and compensatory mechanisms to maintain balance by recruiting postural muscles and displacement of the body's center of mass. METHODS: Twenty-six participants (control or infected) had lower limb muscle onset and center of pressure (COP) displacements assessed prior to perturbation and throughout the entire movement. RESULTS: Semitendinosus (ST) showed delayed onset in the infected group compared to the control group. The percentage of trials with detectable anticipatory postural adjustment was also lower in infected groups in the tibialis anterior and ST. In addition, COP displacement in the infected group was delayed, had a smaller amplitude, and took longer to reach the maximum displacement. CONCLUSIONS: HTLV-1 infected patients have less efficient anticipatory adjustments and greater difficulty recovering their postural control during the compensatory phase. Clinical assessment of this population should consider postural stability during rehabilitation programs.

The hand tremor spectrum is modified by the inertial sensor mass during lightweight wearable and smartphone-based assessment in healthy young subjects.

Tremors are common disorders characterized by an involuntary and relatively rhythmic oscillation that can occur in any part of the body and may be physiological or associated with some pathological condition. It is known that the mass loading can change the power spectral distribution of the tremor. Nowadays, many instruments have been used in the evaluation of tremors with bult-in inertial sensors, such as smartphones and wearables, which can significantly differ in the device mass. The aim of this study was to compare the quantification of hand tremor using Fourier spectral techniques obtained from readings of accelerometers built-in a lightweight handheld device and a commercial smartphone in healthy young subjects. We recruited 28 healthy right-handed subjects with ages ranging from 18 to 40 years. We tested hand tremors at rest and postural conditions using lightweight wearable device (5.7 g) and smartphone (169 g). Comparing both devices at resting tremor, we found with smartphone the power distribution of peak ranging 5 and 12 Hz in both hands. With wearable, the result was similar but less evident. When comparing both devices in postural tremor, there were significant differences in both frequency ranges in peak frequency and peak amplitude in both hands. Our main findings show that in resting condition the hand tremor spectrum had a higher peak amplitude in the 5-12 Hz range when the tremor was recorded with smartphones, and in postural condition there was a significantly (p < 0.05) higher peak power spectrum and peak frequency in the dominant hand tremors recorded with smartphones compared to those obtained with lightweight wearable device. Devices having different masses can alter the features of the hand tremor spectrum and their mutual comparisons can be prejudiced.