Hand grip strength variability during serial testing as an entropic biomarker of aging: a Poincaré plot analysis

Nonlinear Dynamics Analysis of Handgrip Strength Using the Poincaré Plot Method Through Video Processing Techniques

BACKGROUND/OBJECTIVES

The aim of this study was to analyze the nonlinear dynamics of handgrip strength (HGS) in young adults, focusing on hand dominance, by employing the Poincaré plot method to assess short- and long-term variability utilizing dynamometry and video motion capture during sustained isometric contractions.

METHODS

A cross-sectional exploratory study was conducted on 30 healthy subjects (mean age 21.6 ± 1.3 years, 13 males and 17 females), measuring HGS for both the dominant hand (DH) and nondominant hand (NDH) using a Saehan hydraulic dynamometer during 25-s sustained isometric contractions. A GoPro HERO11 Black camera recorded the dynamometer's needle movements, and the video data were analyzed using Kinovea software. Angular values were converted to force using a calibration-based formula, and the Poincaré plot computed variability indices (short-term variability-SD1, long-term variability-SD2, ratio SD1/SD2, and area of the fitting ellipse) for each hand in relation to HGS and angular velocity (AV). Data analysis included descriptive and inferential statistics.

RESULTS

We demonstrated a strong correlation between mechanical and video measurements (p ≤ 0.001), confirming the reliability of the video method. The findings highlight the importance of nonlinear analysis in understanding neuromuscular function and fatigue, revealing significant correlations among HGS, AV, Poincaré indices, and fatigue levels in both hands (p ≤ 0.001). Increased maximum HGS and AV correlated with higher nonlinear variability in force production.

CONCLUSIONS

This study confirms the reliability of the proposed video-based HGS assessment and demonstrates the effectiveness of Poincaré plot analysis for capturing nonlinear variability in HGS.

Health risk assessment and prevalence of work-related musculoskeletal disorders among the aged brick molders, in India

The Brickfield Industry is the major and oldest informal industry in India, where millions of brickfield workers make their livelihood. Aged brickfield workers are also involved in different activities in the brickfield, especially in brick mold activities owing to poor socioeconomic conditions. A cross-sectional study was designed to determine the prevalence of work-related musculoskeletal disorders among the aged brick molders and compare them with aged control subjects. A Nordic Questionnaire was applied to assess the discomfort felt among both groups of workers and the Rapid Upper Limb Assessment (RULA) method was used to evaluate posture during their job. The RULA posture analysis showed that the posture adopted by aged brick molders required changes immediately. The result of the ART tool also stated that the brick molding activities' exposure level was high and required further investigation urgently. The study concluded that due to working in a forward bending posture for a prolonged period, aged brickmolders suffered from severe low back and knee pain along with upper-limb disorders due to repetitive activities.

Association of Gastric Myoelectrical Activity With Ghrelin, Gastrin, and Irisin in Adults With Metabolically Healthy and Unhealthy Obesity

Background and Objective: Functional disturbances of gastric myoelectrical activity (GMA) might exist in obesity. However, studies on its association with the gastric hormones in obesity phenotypes are lacking. The objective was to study the association of GMA with the serum levels of key gastric hormones in different obesity phenotypes.

Methods: A total of 139 adults (31.00 ± 11.12 years) were classified into different metabolic phenotypes of obesity: 1) normal weight-lean (NWL group): BMI <25 kg/m² and the fat-mass index (FMI) ≤9.7 kg/m² in females and ≤6.3 kg/m² in males; 2) metabolically obese normal weight (MONW group): BMI <25 kg/m² and FMI >9.7 kg/m² in females and >6.3 kg/m² in males; 3) metabolically healthy obese (MHO group): BMI ≥25 and FMI ≤9.7 kg/m² in females and ≤6.3 kg/m² in males; and 4) metabolically unhealthy obese (MUO group): BMI ≥25 and FMI >9.7 kg/m² in females and >6.3 kg/m² in males. The GMA was measured at the baseline and post-prandial state using a multichannel electrogastrography with a water load satiety test. The average power distribution by the frequency region and the average dominant frequency were used for analysis. Anthropometric measurements and bioelectric impedance analysis were performed to calculate the FMI and fat-free mass index (FFMI). Serum levels of ghrelin, gastrin, and irisin were measured by ELISA kits according to the manufacturer’s protocol.

Results: Compared to the NWL group, gastrin and ghrelin levels were significantly low in the MUO participants, while irisin was significantly high. The EGG showed significantly lower baseline and 20-min normogastria frequencies in the MHO and MUO groups. In the MHO group, baseline duodenal frequency was positively correlated with the gastrin level, while normogastria times were positively associated with the irisin level and negatively associated with the ghrelin level. In the MUO group, percentages of bradygastria frequencies at 10, 20, and 30 min were positively correlated with the BMI and FFMI. This bradygastria was correlated positively with the irisin level and negatively with the ghrelin level.

Conclusion: The EGG patterns might be associated with obesity-related gastric hormones in different obesity phenotypes. EGG may be a promising clinical tool in obesity assessment. The association of the EGG patterns with hormonal levels needs further investigation for potential practical uses.

What can we learn from physical capacity about biological age? A systematic review

OBJECTIVE

To systematically investigate the relationship between objective measures of physical capacity (e.g., cardio-respiratory fitness or daily step count) and biological age, measured in different ways.

DATA SOURCE

PubMed; SCOPUS - Elsevier API; and Web of Science - ISI 1984-present, as well as contextual search engines used to identify additional relevant publications.

STUDY SELECTION

Cross-sectional and longitudinal studies that assessed the association between objectively measured physical capacity and biological aging in adult individuals (age>18).

RESULTS

Analysis of 28 studies demonstrated that physical capacity is positively associated with biological aging; the most dominant measures of physical capacity are muscular strength or gait speed. The majority of the studies estimated biological aging by a single methodology - either Leukocyte Telomere Length or DNA methylation levels.

CONCLUSIONS

This systematic review of the objective physical capacity measures used to estimate aging finds that the current literature is limited insofar as it overlooks the potential contribution of many feasible markers. We recommend measuring physical capacity in the context of aging using a wide range of modifiable behavioral markers, beyond simple muscle strength or simple gait speed. Forming a feasible and diversified method for estimating physical capacity through which it will also be possible to estimate biological aging in wide population studies is essential for the development of interventions that may alleviate the burden of age-related disease.

Nonlinear Dynamics of Reaction Time and Time Estimation during Repetitive Test

(1) Background: In this research, we aimed to investigate a computational model of repetitive reaction time (RT) and virtual reaction time (VRT) testing. (2) Methods: The study involved 180 subjects (50 men, 130 women, mean age 31.61 ± 13.56 years). The data were statistically analyzed through the coefficient of variation (CV) and the Poincaré plot indicators. (3) Results: We obtained an excellent level of reliability for both sessions of testing and we put into evidence a relationship of association of the RT and VRT with the subjects' age, which was more pregnant for RT (p < 0.05). For both RT and VRT data series, we determined a consistent closer association between CV and the Poincaré plot descriptors SD1, SD2 (SD-standard deviation), and the area of the fitting ellipse (AFE) (p < 0.01). We reported an underestimation of the time interval of 2 s during the VRT session of testing, with an average value of CV of VRT, the equivalent of the Weber fraction, of 15.21 ± 8.82%. (4) Conclusions: The present study provides novel evidence that linear and nonlinear analysis of RT and VRT variability during serial testing bring complementary insights to the understanding of complex neurocognitive processes implied in the task execution.

Cancer treatment-induced NAD+ depletion in premature senescence and late cardiovascular complications

Numerous studies have revealed the critical role of premature senescence induced by various cancer treatment modalities in the pathogenesis of aging-related diseases. Senescence-associated secretory phenotype (SASP) can be induced by telomere dysfunction. Telomeric DNA damage response induced by some cancer treatments can persist for months, possibly accounting for long-term sequelae of cancer treatments. Telomeric DNA damage-induced mitochondrial dysfunction and increased reactive oxygen species production are hallmarks of premature senescence. Recently, we reported that the nucleus-mitochondria positive feedback loop formed by p90 ribosomal S6 kinase (p90RSK) and phosphorylation of S496 on ERK5 (a unique member of the mitogen-activated protein kinase family that is not only a kinase but also a transcriptional co-activator) were vital signaling events that played crucial roles in linking mitochondrial dysfunction, nuclear telomere dysfunction, persistent SASP induction, and atherosclerosis. In this review, we will discuss the role of NAD⁺ depletion in instigating SASP and its downstream signaling and regulatory mechanisms that lead to the premature onset of atherosclerotic cardiovascular diseases in cancer survivors.

Research on physical activity variability and changes of metabolic profile in patients with prediabetes using Fitbit activity trackers data

BACKGROUND

Monitoring physical activity with consumers wearables is one of the possibilities to control a patient's self-care and adherence to recommendations. However, clinically approved methods, software, and data analysis technologies to collect data and make it suitable for practical use for patient care are still lacking.

OBJECTIVE

This study aimed to analyze the potential of patient physical activity monitoring using Fitbit physical activity trackers and find solutions for possible implementation in the health care routine.

METHODS

Thirty patients with impaired fasting glycemia were randomly selected and participated for 6 months. Physical activity variability was evaluated and parameters were calculated using data from Fitbit Inspire devices.

RESULTS

Changes in parameters were found and correlation between clinical data (HbA1c, lipids) and physical activity variability were assessed. Better correlation with variability than with body composition changes shows the potential to include nonlinear variability parameters analysing physical activity using mobile devices. Less expressed variability shows better relationship with control of prediabetic and lipid parameters.

CONCLUSIONS

Evaluation of physical activity variability is essential for patient health, and these methods used to calculate it is an effective way to analyze big data from wearable devices in future trials.

The Efficacy of Antioxidant Oral Supplements on the Progression of COVID-19 in Non-Critically Ill Patients: A Randomized Controlled Trial

Modulation of cytokine production using immunonutrition is a relatively novel concept to improve outcomes among patients with SARS-CoV-2 infection and is now hypothesized to help manage COVID-19, however, clinical evidence is lacking. This prospective, double-blinded, randomized parallel-controlled interventional clinical trial investigated the effect of antioxidant supplements on inflammatory cytokines and disease progression in non-critically ill patients. A total of 87 hospitalized COVID-19 patients were randomized using computer-generated-randomization into the supplement group (n = 18) and the placebo group (n = 16) for 10 days. Baseline and final nutritional screening via nutrition risk screening (NRS-2002) and subjective global assessment (SGA), as well as the recording of anthropometric, clinical, biochemical, and functional parameters, were done. Serum ferritin level, cytokine storm parameters such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein 1(MCP-1), C-reactive protein, total leukocyte count, lymphocytic count, and neutrophil-to-lymphocyte ratio were measured. Anthropometric and clinical parameters showed nonsignificant differences between groups. The hematology profile showed improvement in lymphocyte count in the supplement group. However, levels of alkaline phosphatase, IL-6, TNF-α, and MCP-1 were significantly lower in the supplement group. In conclusion, antioxidant oral supplementation significantly reduced the cytokine storm and led to partial improvements in clinical parameters among patients with non-critical COVID-19.

The Applicability of the Poincaré Plot in the Analysis of Variability of Reaction Time during Serial Testing

(1) Background: This study aims to put into evince the relationship between the variability of the reaction time (RT) during repeated testing, expressed through indicators extracted by the Poincaré plot method, and the age of the participants, their self-reported health (SRH), and level of perceived anxiety. (2) Methods: The study was performed using computerized RT testing software. An observational cross-sectional study was performed on a group of 120 subjects (mean age 42.33 ± 21.12 years), sex ratio men to women 1.14:1. Data were processed through descriptive and inferential statistics. The Poincaré plot method was applied in the analysis of the RT series of data, by calculating the indicators SD₁, SD₂, SD₁/SD₂, and area of the fitting ellipse (AFE) (3) Results: We provided evidence of the excellent reliability of the web-based RT serial testing (Cronbach’s Alpha 0.991) with this sample group. Our results showed that age is an important predictor for mean values of RT, while SD₁, SD₂, and AFE indicators are for SRH (p < 0.01). (4) Conclusions: the variability of RT, expressed by the Poincaré plot indicators, reflects the health status rather than the aging of the subjects and is barely influenced by their level of anxiety.

Handgrip Strength as a Complementary Test for Mobility Limitations Assessment in Acutely Hospitalized Oldest Old

Clinically viable screening tools for detecting individuals at heightened risk for mobility limitations is warranted. However, it remains unclear in acutely hospitalized patients (>75 years) whether handgrip strength might be a good predictor for "proxy" muscle strength. To examine the reliability and validity of handgrip strength test in acute hospitalized older adults in comparison with other standardized muscular strength tests, and to examine its ability to discriminate between presence and absence of mobility limitations. Cross-sectional study. A total of 234 patients (mean age 87.0 years, 46% women) admitted to a tertiary public hospital between 2016 and 2017 were recruited. Maximal (one repetition maximum) and power muscle output of the upper and lower extremity along with functional capacity (as assessed with Barthel index and the Short Physical Performance Battery [SPPB]), and cognitive function was measured at admission. Functional impairment (mobility limitations) was defined at SPPB ≤7 points. Pearson's correlation and multivariable linear regression were evaluated between handgrip test and maximal and muscle power output as the reference method to assess concurrent validity. Receiver operating characteristic analysis was used to estimate handgrip strength cutoff point for likelihood of mobility limitations to assess predictive validity. Findings show moderate-to-strong correlations between standardized muscular strength (reference methods) and handgrip strength test (r = 0.534-0.725). All muscular strength tests show moderate accuracy (area under curve >0.7). Handgrip strength shows the higher positive predictive value (87%) and, therefore, a lower number of false positives. The overall handgrip strength cutoff point for likelihood of mobility limitations was 18.4 kg for men and women. Handgrip strength may be a useful tool for detecting acutely hospitalized older who are at risk of mobility limitations and could aid in focusing interventions on those with higher risk. Randomized clinical trial: NCT02300896.