Healthy Young Volunteers Research Articles

In-vivo kinematics of the trapeziometacarpal joint in dynamic pinch motion using four-dimensional computed tomography imaging.

CT imaging precisely and quantitatively analyzes the kinematics of the carpal bones to evaluate the etiology of related osteoarthritis. Previous studies have investigated the kinematics of the trapeziometacarpal joint using static CT scans of various postures including the pinch position. This study analyzed the in-vivo kinematics of the trapeziometacarpal joint during dynamic pinch motion in young healthy volunteers using four-dimensional CT. Twelve healthy young volunteers participated in this study. Each participant held the pinch meter between their thumb and index finger and pinched it with maximum force for a period of 6s. This series of movement was recorded using a four-dimensional CT. The surface data of the trapezium and first metacarpal of all frames were reconstructed, and bone movement at the trapeziometacarpal joint was calculated using sequential three-dimensional registration. The instantaneous pinch force of each frame was measured using a pointer on a pinch meter that was reconstructed from the CT data. The first metacarpal was abducted (15.9 ± 8.3°) and flexed (12.2 ± 7.1°) relative to the trapezium, and significantly translated to the volar (0.8 ± 0.6mm) and ulnar directions (0.9 ± 0.8mm) with maximum pinch force. This movement consistently increased with the pinch force. This study successfully employed 4D-CT to precisely demonstrate changes in rotation and translation at the trapeziometacarpal joint during pinch motion for various instantaneous forces.

Imaging evaluation of physical activity effect on knee articular cartilage

IntroductionHyaline cartilage is a complex tissue with great load absorbing-function. Studies showed that moderate exercise can have a positive effect on chondral matrix composition but excessive can be harmful to cartilage. ObjectivesEvaluate knee cartilage thickness before and after physical activity (running) in healthy young individuals. MethodsTen healthy young adult male volunteers aged between 18 and 21 years old were selected to undergo magnetic resonance imaging examination of the right knee to measure the cartilage thickness of the anterior, medial, and lateral compartments before and after 1 hour of continuous running. Cartilage thickness measurements were performed by a radiologist who did not know the identity of the volunteers or the moment of the evaluation (before or after the exercise). ResultsThe subjects' mean age, height, and weight were 19.5 years, 1.80 m, and 75.2 kg, respectively, with a mean body mass index of 23.14. There was a decrease in chondral thickness after running on all surfaces evaluated. The changes that were relevant (P < .05) were all the medial femoral condyle, the anterior portion of the lateral femoral condyle, the anterior portion of the lateral plateau, the entire surface of the patella and trochlea. The greatest difference in thickness between before and after exercise was observed in the lateral facet of the patella (−0.224 mm) followed by the anterior surface of the medial femoral condyle (−0.186 mm). In proportional values, the highest decrease occurred in the anterior portion of the medial femoral condyle (−11.42%). ConclusionThere was a decrease in knee chondral thickness after 60 minutes of running, being statistically significant in the medial femoral condyle, anterior surface of the lateral femoral condyle, and lateral plateau and patellofemoral joint (patella and trochlea). Level of evidenceIV (Case Series).

Biomechanical evaluation of the anterior talo-fibular and calcaneo-fibular ligaments using shear wave elastography in young healthy adults

BackgroundThe objective of this study was to evaluate the stiffness of the anterior talo-fibular ligament (ATFL) and calcaneo-fibular ligament (CFL) using shear wave elastography (SWE) with the ankle in the neutral position and in varus, in young healthy adult volunteers. We also evaluated the reliability and reproducibility of the SWE measurements. HypothesisThe stiffness of both ligaments increases with increasing ankle varus. SWE may be a reliable tool for evaluating the lateral collateral ligament complex of the ankle. Material and methodsWe used SWE to evaluate both ankles of each of 20 healthy volunteers (10 females and 10 males). For each test, the foot was placed on a hinged plate and tested in the neutral position and in 15° and 30° of varus. Stiffness was evaluated based on shear wave velocity (SWV). ResultsStiffness of both the ATFL and CFL was minimal in the neutral position (2.06m/s and 3.43m/s, respectively). Stiffness increased significantly for both ligaments in 15° of varus (2.48m/s and 4.11m/s, respectively; p<0.0001) and was greatest in 30° of varus (3.15m/s and 4.57m/s, respectively; p<0.0001). ATFL stiffness was greater in males than in females in 15° (p=0.04) and 30° (p=0.02) of varus. For the CFL, in contrast, stiffness was not different between males and females. Stiffness of the ATFL and CFL was not associated with age, dominant side, height, or foot morphology. No correlations were found between stiffness of the two ligaments in any of the positions. Repeating each measurement three times produced excellent concordance for both ligaments in all three positions. ConclusionThe ATFL and CFL are the main lateral stabilisers of the ankle, and each exerts a specific function. Their stiffness increases with the degree of varus. This study describes a protocol for evaluating ATFL and CFL density by SWE, which is a reliable and reproducible technique that provides a normal range. Level of evidenceIV.

The Effect of Multiple Factors on Working Memory Capacities: Aging, Task Difficulty, and Training.

Working memory (WM) is a memory system with a limited capacity that can process and store information temporarily in the performing of cognitive tasks. Despite WM is known to be influenced by age, the difficulty of tasks and trained or not from behavior studies, little is known about their relationships from the aspect of the brain functional network. Our goal was to explore the factor of aging-related changes of WM with brain functional networks. In this study, 25 healthy elderly and 23 healthy young volunteers were recruited for electroencephalogram (EEG) recording during the visual WM task with four difficulty levels (1-4 backs). In each back, we repeat the experiment with four sessions, and we add training sections between session one and session two as well as between session two and session three. However, we remove any training section between session three and session four in order to evaluate the impact of forgetting on WM in different age groups. After the experiment, we utilized graph theoretical analysis to characterize the brain functional network in three frequency bands (alpha, beta, and theta). From the well-designed experiment, we found that physiological aging influences brain network connectivity and makes the functional brain network less differentiated. Moreover, there is an inverse relationship between alpha activity and WM load for the elderly group, which is absent in the young group. At the same time, theta band activity will be correlated with behavioral performance for the elderly group with WM training between sessions, which is also absent in the young group. To further study the influence of difficulty of tasks and training on the WM, we distinguish the tasks with quantified topological characteristics, and the classification results manifest that the training is more effective for the young group. Finally, through the establishment of a brain map before and after training, we find that the right parietal lobe plays an important role in the training of WM for the elderly group whereas the beta band plays an important role in WM for both the elderly group and the young group. Taken together, our findings clarify the underlying mechanism of WM under different frequency bands in terms of physiological aging, the influence of training, and task difficulty. the working memory capacities can be uncovered in terms of the combination of three-way ANOVA and EEG-based graph theoretical analysis.

In healthy volunteers the Miami-J® cervical collar causes swallow dysfunction. This may increase the risk of aspiration; of particular potential consequence in older people with neck injury

BackgroundIn young healthy volunteers a cervical hard collar has been shown to change swallowing physiology. The risk of aspiration pneumonia increases with age. MethodsIn this open prospective dual-arm controlled trial without randomisation there were 23 patients divided into two cohorts: 11 older (mean age 84) and 12 younger (mean age 25).A series of video fluoroscopy (VF) swallow studies were performed without a cervical collar, followed by the same series of VF with a Miami-J® cervical collar fitted. The Modified Barium Swallow Impairment Profile (MBSImPTM©) and Penetration-Aspiration Scale (PAS) were used to define and score swallow function and level of aspiration without and with the collar fitted. ResultsAn increase in the median MBSImPTM© score amongst all participants in the oral phase of swallow (p = 0.01) and combined oral and pharyngeal phase of swallow (p = 0.006) was seen when volunteers were fitted with the Miami-J® collar, compared to no collar.When wearing the collar deterioration in swallow function and small increases in PAS level were more marked in the older cohort, but these latter findings were not statistically significant. ConclusionsCervical hard collars change swallowing physiology in younger and older volunteers. Whilst we did not measure a statistically significant difference in the PAS level pre- and post- collar wearing, we feel it is important to highlight these changes in swallowing physiology and speculate that with collar use there is a potential risk of aspiration associated with these changes.Potential risk of aspiration should be carefully balanced with the benefit gained from collar use in the management of cervical spine injury (both in conservative and postoperative management). Although this is a small study it is important to highlight an area of concern of particular importance in the older population who have physiological changes to the swallow that occur with age (presbyphagia) and where baseline risk of aspiration is higher.

Incidence of G6pd Deficiency in Young Asymptomatic Males in Pakistan

Background: NADPH is crucial for glutathione reduction. Deficiecy of G6PD leads to excessive oxidised glutathione that denatures hemoglobin and forms Heinz bodies. Heinz bodies damages RBC membrane and cause premature removal of cells by spleen. G6PD deficiency is the most common X-linked inherited red cell enzymopathy that leads to hemolytic anemia and neonatal jaundice in enzyme deficient patients under oxidative stress. G6PD is the rate limiting enzyme in pentose phosphate pathway, a dominant form of glycolysis in RBCs. G6PD converts glucose-6 phosphate into 6-phosphonogluconolactone and reduces NADP to NADPH. Objective: To determine incidence of G6PD deficiency in young healthy males in Pakistan. Study design: A descriptive cross sectional study Place and duration: Study was carried out at PAF Hospital Sargodha from Jan 2021 to Feb 2023 Methodology: G6PD levels were checked in young healthy male volunteers of 12 to 18 years of age, after taking informed consent from subjects and their parents. Results: Out of 1493 volunteers, only 61 were G6PD deficient and rest all had normal levels. This shows an incidence of 4.08% in our population. Conclusion: Comparing with previous studies suggests 2-4% incidence of G6PD deficiency in Pakistani population. A larger study including females and studying variants of disease is needed. Patients with lab confirmed P.Vivax should get screened for G6PD deficiency, so that they receive Primaquine. Keywords: Incidence, G6PD deficiency, Malaria, Primaquine.

0492 Variability in High Altitude Sleep Disordered Breathing and Impact of Acclimatization

Abstract Introduction Individuals who travel to high altitude experience variable levels of poor sleep quality and sleep disordered breathing, which can have neurocognitive and other systemic impacts. Past studies by our group and others have shown that the apnea hypopnea index (AHI) increases, and nocturnal oxygen saturation decreases at higher altitude. This may change over time with acclimatization to environmental hypoxemia. The aim of this study was to examine the trajectory and variability in high altitude sleep disordered breathing effects in healthy young adult volunteers. Methods Twenty healthy volunteers were recruited from a local university (35% women), mean age 23.5(20.0, 32.2) years and BMI of 30.0(28.0, 35.9) kg/m2. Peripheral Arterial tonometry based home sleep apnea tests (HSAT; WatchPat One) was performed on all subjects at sea level up to three days prior to transportation via car to high altitude (3800m White Mountain Research Center - Barcroft Station, CA). Participants continued HSAT testing for three consecutive nights at high altitude sleeping in any position, without oxygen, acetazolamide, or use of any other medications impacting sleep or breathing. Mixed effects modeling was used to compare sleep parameters across nights. Results Subjects' characteristics: median (IQR)[range] age 23(20,32)[19,39] years, BMI 30(28, 36)[23,48] kg/m2, 35% women. AHI at altitude night 1 (67±4 events/hour) was significantly higher than sea level (7±4 events/hour; P&amp;lt; 0.001). Mean sleep SpO2 at altitude night 1 (79±1%) was significantly lower than sea level (95±1%; P&amp;lt; 0.0001). There was no statistically significant change in AHI or mean sleep SpO2 on nights 1-3; however substantial variability was noted between individual trajectories. Conclusion Healthy young adults exhibit severe Sleep Disordered Breathing when traveling to high altitude. Despite acclimatization, the severity of Sleep Disordered Breathing remained relatively unchanged overall. However substantial differences in individual trajectories were apparent. Larger studies are needed to understand how differences in genetics, sex, and other factors might impact Sleep Disordered Breathing at altitude. In addition, the impacts of (or tolerances to) altitude are likely to be broadly informative towards Sleep Disordered Breathing, hypoxemia, and other areas. Support (if any) N/A

Shorter TR combined with finer atlas positively modulate topological organization of brain network: A resting state fMRI study

ABSTRACT Background: The use of shorter TR and finer atlases in rs-fMRI can provide greater detail on brain function and anatomy. However, there is limited understanding of the effect of this combination on brain network properties. Methods: A study was conducted with 20 healthy young volunteers who underwent rs-fMRI scans with both shorter (0.5s) and long (2s) TR. Two atlases with different degrees of granularity (90 vs 200 regions) were used to extract rs-fMRI signals. Several network metrics, including small-worldness, Cp, Lp, Eloc, and Eg, were calculated. Two-factor ANOVA and two-sample t-tests were conducted for both the single spectrum and five sub-frequency bands. Results: The network constructed using the combination of shorter TR and finer atlas showed significant enhancements in Cp, Eloc, and Eg, as well as reductions in Lp and γ in both the single spectrum and subspectrum (p < 0.05, Bonferroni correction). Network properties in the 0.082–0.1 Hz frequency range were weaker than those in the 0.01–0.082 Hz range. Conclusion: Our findings suggest that the use of shorter TR and finer atlas can positively affect the topological characteristics of brain networks. These insights can inform the development of brain network construction methods.

59 First-in-Human Controlled Exposure to Inhaled Graphene Oxide

Abstract Graphene oxide nanomaterials have been developed for wide-ranging applications, but has potential safety concerns for human health. Controlled inhalation exposures in human volunteers have been a vital means to determine the effects and mechanisms of ultrafine particles in air pollution, however, few studies have used this approach to explore the effects of nanomaterials. We conducted a double-blind randomised controlled study to determine whether inhalation of graphene oxide affects pulmonary or cardiovascular function. A high purity graphene oxide was synthesised with a thickness of 1-2 layers in two sizes: ‘small’ (lateral dimensions: 100-1700 nm) and ‘ultrasmall’ (30-500 nm). Graphene oxide particles at 200 µg/m3, or filtered air, were inhaled for 2 hours by 14 young healthy volunteers on repeated visits, with measurement of cardiorespiratory parameters before and across 4 hours after exposure. Graphene oxide exposure was well-tolerated with no adverse effects. Heart rate, blood pressure, lung function and inflammatory markers were unaffected by graphene oxide irrespective of particle size. GO did not change blood biomarkers of coagulation, however, there was a mild increase in thrombus formation in an ex vivo model of arterial injury. Proteomics revealed very few differential plasma proteins. Overall, acute inhalation of graphene oxide was not associated with overt detrimental effects in healthy humans. These findings demonstrate the feasibility of carefully controlled human exposures for risk assessment of graphene nanomaterials.

Pharmacokinetics comparison of vardenafil as administered by an intranasal spray formulation vs a 10-mg oral tablet.

Oral vardenafil (VDF) tablet is an effective treatment for erectile dysfunction (ED), but intranasal administration with a suitable formulation can lead to a faster onset of action and offer more convenient planning for ED treatment. The primary purpose of the present pilot clinical study was to determine whether intranasal VDF with an alcohol-based formulation can result in more "user-friendly pharmacokinetics" as compared with oral tablet administration. This single-dose randomized crossover study was conducted in 12 healthy young volunteers receiving VDF as a 10-mg oral tablet or 3.38-mg intranasal spray. Multiple blood concentrations were obtained, and VDF concentrations were determined with a liquid chromatography-tandem mass spectrometry assay. Pharmacokinetic parameters following each treatment were compared and adverse events assessed. Pharmacokinetic parameters were obtained: apparent elimination rate constant, elimination half-life, peak concentration, peak time, total area under the curve, and relative bioavailability. Although mean apparent elimination rate constant, elimination half-life, peak concentration, and total area under the curve were similar between intranasal and oral administration, the median peak time from intranasal was much shorter (10vs 58minutes, P < .001, Mann-Whitney U test). The variability of the pharmacokinetic parameters was also less with intranasal than oral administration. The relative bioavailability of intranasal to oral was 1.67. Intranasal VDF caused transient but tolerable local nasal reactions in 50% of subjects. Other adverse events (eg, headache) were similar between the treatments. The incidence of adverse events was, however, significantly less in the second treatment after initial exposure to VDF. No serious adverse events were noted. Intranasal VDF potentially offers a more timely and lower dose for the treatment of ED in patients who can tolerate the transient local adverse reactions. The strength of this study is its randomized crossover design. Because the study was conducted in 12 healthy young subjects, the results may not reflect those observed in elderly patients who may be likely taking VDF for ED. Nevertheless, the changes of pharmacokinetic parameters in the present study are likely a reflection of the differences between intranasal and oral administration of the formulations. Our study indicated that the present VDF formulation, when administered intranasally, can achieve a more rapid but similar plasma concentration with only about one-third dose when compared with the oral administration.

Can placebo or nocebo pills improve or impair cognition performance?

Although the placebo effect is well known to affect many behaviors, the effects on cognitive performance are less well investigated. In this study, the effects of a placebo and a nocebo manipulation on cognitive performance was investigated in healthy young participants in an unblinded between-subjects study. In addition, the participants were asked about their subjective experience in the placebo and nocebo condition. The data suggested that the placebo condition induced the feeling of being more attentive and more motivated and the nocebo condition induced a feeling of being less attentive and alert and that they performed less well than normal. However, no placebo or nocebo effects were found on the actual performance on word learning, working memory, Tower of London task, or spatial pattern separation. These findings further support the notion that placebo or nocebo effects are not likely to occur in young healthy volunteers. However, other studies suggest that placebo effects can be found in implicit memory tasks and in participants with memory problems. Further placebo/nocebo studies are indicated using different experimental designs and different populations in order to better understand the placebo effect on cognitive performance.

Quality assessment, variability and reproducibility of anatomical measurements derived from T1-weighted brain imaging: The RIN–Neuroimaging Network case study

Initiatives for the collection of harmonized MRI datasets are growing continuously, opening questions on the reliability of results obtained in multi-site contexts.Here we present the assessment of the brain anatomical variability of MRI-derived measurements obtained from T1-weighted images, acquired according to the Standard Operating Procedures, promoted by the RIN-Neuroimaging Network. A multicentric dataset composed of 77 brain T1w acquisitions of young healthy volunteers (mean age = 29.7 ± 5.0 years), collected in 15 sites with MRI scanners of three different vendors, was considered. Parallelly, a dataset of 7 “traveling” subjects, each undergoing three acquisitions with scanners from different vendors, was also used. Intra-site, intra-vendor, and inter-site variabilities were evaluated in terms of the percentage standard deviation of volumetric and cortical thickness measures. Image quality metrics such as contrast-to-noise and signal-to-noise ratio in gray and white matter were also assessed for all sites and vendors.The results showed a measured global variability that ranges from 11% to 19% for subcortical volumes and from 3% to 10% for cortical thicknesses. Univariate distributions of the normalized volumes of subcortical regions, as well as the distributions of the thickness of cortical parcels appeared to be significantly different among sites in 8 subcortical (out of 17) and 21 cortical (out of 68) regions of i nterest in the multicentric study.The Bland-Altman analysis on “traveling” brain measurements did not detect systematic scanner biases even though a multivariate classification approach was able to classify the scanner vendor from brain measures with an accuracy of 0.60 ± 0.14 (chance level 0.33).

Second to Fourth Digit Ratio and Exercise Performance in Untrained Adult Males

This study was based on a random sample from a Prospective Cohort study including one hundred healthy young untrained male volunteers, with mean age ± standard deviation (SD) of 22.820 ± 2.271 years. The aim of this study was to evaluate the role of the digit ratio as an indicator for the performance of untrained adult males in endurance sports. The parameters that have been measured were: Index and ring fingers length of both right and left hand, body weight, height, waist and hip circumferences, body composition (including: fat, muscle and water percents) and exercise performance (including: distance and time). The descriptive analyses of this study showed that normative values of male 2D:4D ratio vary between 0.912-1.036. and it also revealed that there is a strong inverse relation-ship between digit ratio of the subjects and exercise performance according to the distance and time; as the subject briskly walked on the treadmill at fasting state

Second to Fourth Digit Ratio and Exercise Performance in Untrained Adult Males

This study was based on a random sample from a Prospective Cohort study including one hundred healthy young untrained male volunteers, with mean age ± standard deviation (SD) of 22.820 ± 2.271 years. The aim of this study was to evaluate the role of the digit ratio as an indicator for the performance of untrained adult males in endurance sports. The parameters that have been measured were: Index and ring fingers length of both right and left hand, body weight, height, waist and hip circumferences, body composition (including: fat, muscle and water percents) and exercise performance (including: distance and time). The descriptive analyses of this study showed that normative values of male 2D:4D ratio vary between 0.912-1.036. and it also revealed that there is a strong inverse relation-ship between digit ratio of the subjects and exercise performance according to the distance and time; as the subject briskly walked on the treadmill at fasting state

A magnetic resonance imaging (MRI) study of changes in the angle between the tracheal and laryngeal axes in the sniffing, neutral and extended head and neck positions

Background; Although the sniffing position has historically been used for conventional laryngoscopy, the ideal position for videolaryngoscopy is yet to be elucidated. When a hyperangulated blade is utilised in videolaryngoscopy, despite improved glottic visualisation, the acute angle between the laryngeal and tracheal axes results in the inability to advance the tube into the trachea. We hypothesise that the position that produces the smallest angle between the laryngeal and tracheal axes would most likely facilitate passage of a tube into the trachea during videolaryngoscopy using a hyperangulated blade. Methods20 healthy young adult volunteers underwent magnetic resonance imaging scanning in three anatomic positions: head in the neutral position, in the sniffing position and in the extended position. In total 60 T2-weighted sagittal magnetic resonance images were obtained and the following measurements were made: angle A (the angle between the laryngeal and tracheal axes), angle B (the angle between the laryngeal and pharyngeal axes), angle C (the angle between the pharyngeal and oral axes), angle D (the angle between the laryngeal axis and line of vision) and angle E (the angle between the line of vision and pharyngeal axis). ResultsMean (SD) angle A (in ◦) in neutral, sniffing and extended positions were 20.7 (6.8), 10.8 (6.9) and 30.5 (5.2) with p < 0.001. Angle A and C were significantly reduced when the head position was shifted from neutral to sniffing position. Angle D was smallest in the extended position. The difference in all five angles in three positions was statistically significant (p < 0.001). ConclusionAngle A was smallest in the sniffing position, therefore this position is most likely produce a better alignment between laryngeal and tracheal axes.

Assessment of barium diffusion from therapeutic mud wrapped in micro-perforated polyethylene bags towards the human organism

Barium is present within the clay-derived therapeutic mud packs deposed on the patient's skin for treating some rheumatologic conditions. We studied in twenty-four young healthy volunteers the diffusion of Ba from mud wrapped in micro-perforated polyethylene bags and soaked in mineral water. No significant systematic increase in plasma or urine Ba levels was evidenced when comparing pre- and post-treatment samples using inductively-coupled plasma mass spectrometry. These levels were markedly inferior to the recommended thresholds in nearly all the participants. Noticeably variability in blood and especially urine Ba concentrations was large and mainly explained by environmental exposure (alimentation). Interestingly, we evidenced an intense Ba accumulation within the therapeutic mud at the end of the regimen. Because we chose a clay with one of the highest Ba content available in France for medical therapy and participants with an optimal transcutaneous diffusion capacity (young individuals with low-fat mass), we conclude unambiguously that there is no risk of Ba overexposure in patients receiving pelotherapy according to the procedure used in French medical spas.

Unobtrusive Human Fall Detection System Using mmWave Radar and Data Driven Methods

As the population ages, health issues like injurious falls demand more attention. One solution is to use wearable devices to detect falls. Nevertheless, most of these devices raise obtrusiveness, and older people generally resist or might forget to wear them. The millimeter-wave (mmWave) radar technology was used in this study to unobtrusively detect human falls. Data were collected from healthy young volunteers with the radar mounted on the side wall (trial 1) or overhead (trial 2) of an experimental room. A set of features were manually extracted from the data point clouds; then, multilayer perceptron (MLP), random forest (RF), <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> -nearest neighbor (KNN), and support vector machine (SVM) classifiers were applied on the features. Additionally, we devised a convolutional neural network (CNN)-based deep learning model for the underlying fall detection problem that receives a 3-D representation of the point cloud data, known as occupancy grid, as the input. The optimal installation position of the radar sensor was unknown. Therefore, the sensor was mounted on side wall and on the ceiling of the room to allow the performance comparison between these sensor placements. RF classifier achieved the best results in trial 2 (an accuracy of 92.2%, a recall of 0.881, a precision of 0.805, and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${F}1$ </tex-math></inline-formula> -score of 0.841), and the proposed CNN model achieved slightly better results comparing to the RF method in trial 2 (an accuracy of 92.3%, a recall of 0.891, a precision of 0.801, and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${F}1$ </tex-math></inline-formula> -score of 0.844). These results suggest that the development of an unobtrusive monitoring system for fall detection using mmWave radar is feasible.

Analysis of Blood Flow in the Macula and Optic Nerve Head in Healthy Young Volunteers Using Laser Speckle Flowgraphy.

To assess optic nerve head (ONH) and macular blood flow in young healthy volunteers using laser speckle flowgraphy (LSFG). This is a prospective single-center study conducted at the Department of Ophthalmology, University Hospital Zurich from May to November 2021. Young, healthy men aged ≥ 18 years without ocular or systemic diseases were included. A corrected visual acuity (VA) of 0.0 logMAR or better in both eyes and an intraocular pressure (IOP) of 21 mmHg or lower were required for inclusion. Subjects exceeding a spherical equivalent (SE) of ± 6 diopters (dpt) were excluded. Blood flow in the macula and the ONH was recorded using the Nidek LSFG RetFlow device (Nidek Company, Ltd., Hirioshi-cho, Japan). Laser power was set to 0.5 Millivolts (mV). Mean blur rate (MBR) was recorded as a parameter for blood flow. MBR is a calculated parameter that represents relative blood flow velocity correlated with the real anatomical blood flow rate. Colored heat maps of the recorded retinal area were generated automatically by the RetFlow device. Final analyses included 83 eyes of 43 male volunteers. Mean age was 21.9 years (SD ± 1.5, range: 20 to 29). Mean corrected VA was - 0.1 logMAR (SD ± 0.05, range: - 0.2 to 0.0), mean IOP was 15.4 mmHg (SD ± 2.5, range: 8.5 to 18.5), and mean SE was - 0.3 dpt (SD ± 1.2, range: - 5.0 to 1.2). Mean ONH MBR was 37.44 (SD ± 7.9, range: 22.5 to 53.5) and mean macular MBR was 27.8 (SD ± 9.7, range: 6.4 to 57.7). Pearson's Test showed a strong correlation between macular and papillary blood flow (p < 0.05, coefficient: 0.647). This study provides both ONH and macular blood flow data in a healthy young male population, showing a strong correlation between ONH and macular blood flow in the examined eyes. Further investigations are required to assess the validity of MBR as a parameter for the combined evaluation of retinal blood flow at the macula and ONH in healthy volunteers and patients with various diseases.

Finite Element Analysis of the Mechanical Strength of Phalangeal Osteosynthesis Using Kirschner Wires.

Background: Kirschner wire (K-wire) fixation is widely used to repair metacarpal and phalangeal fractures. In this study, we simulated K-wire osteosynthesis of a 3-dimensional (3D) phalangeal fracture model and investigated the fixation strength at various K-wire diameters and insertion angles to clarify the optimal K-wire fixation method for phalangeal fractures. Methods: The 3D phalangeal fracture models were created by using computed tomographic (CT) images of the proximal phalanx of the middle finger in five young healthy volunteers and five elderly osteoporotic patients. Two elongated cylinders representing K-wires were inserted according to various cross-pinning methods; the wire diameters were 1.0, 1.2, 1.5 and 1.8 mm, and the wire insertion angles (i.e. the angle between the fracture line and the K-wire) were 30°, 45° and 60°. The mechanical strength of the K-wire fixed fracture model was investigated by using finite element analysis (FEA). Results: The fixation strength increased with increasing wire diameter and insertion angle. Insertion of 1.8-mm wires at 60° achieved the strongest fixation force in this series. Fixation strength was generally stronger in the younger group than the elderly group. Dispersion of stress to cortical bone was a critical factor to increase fixation strength. Conclusions: We developed a 3D phalangeal fracture model into which we inserted K-wires; using FEA, we clarified the optimal crossed K-wire fixation method for phalangeal fractures. Level of Evidence: Level V (Therapeutic).

Neural and behavioral adaptations to frontal theta neurofeedback training: A proof of concept study.

Previous neurofeedback research has shown training-related frontal theta increases and performance improvements on some executive tasks in real feedback versus sham control groups. However, typical sham control groups receive false or non-contingent feedback, making it difficult to know whether observed differences between groups are associated with accurate contingent feedback or other cognitive mechanisms (motivation, control strategies, attentional engagement, fatigue, etc.). To address this question, we investigated differences between two frontal theta training groups, each receiving accurate contingent feedback, but with different top-down goals: (1) increase and (2) alternate increase/decrease. We hypothesized that the increase group would exhibit greater increases in frontal theta compared to the alternate group, which would exhibit lower frontal theta during down- versus up-modulation blocks over sessions. We also hypothesized that the alternate group would exhibit greater performance improvements on a Go-NoGo shooting task requiring alterations in behavioral activation and inhibition, as the alternate group would be trained with greater task specificity, suggesting that receiving accurate contingent feedback may be the more salient learning mechanism underlying frontal theta neurofeedback training gains. Thirty young healthy volunteers were randomly assigned to increase or alternate groups. Training consisted of an orientation session, five neurofeedback training sessions (six blocks of six 30-s trials of FCz theta modulation (4-7 Hz) separated by 10-s rest intervals), and six Go-NoGo testing sessions (four blocks of 90 trials in both Low and High time-stress conditions). Multilevel modeling revealed greater frontal theta increases in the alternate group over training sessions. Further, Go-NoGo task performance increased at a greater rate in the increase group (accuracy and reaction time, but not commission errors). Overall, these results reject our hypotheses and suggest that changes in frontal theta and performance outcomes were not explained by reinforcement learning afforded by accurate contingent feedback. We discuss our findings in terms of alternative conceptual and methodological considerations, as well as limitations of this research.