Mean Lap Research Articles

PO-02-222 CARDIORESPIRATORY FITNESS AND COMPREHENSIVE ATRIAL REMODELLING IN PATIENTS WITH SYMPTOMATIC ATRIAL FIBRILLATION

Cardiorespiratory fitness (CRF) are important independent prognostic markers in AF. The influence of CRF on atrial (LA) electrical and functional remodelling in AF is unknown. To use cardiopulmonary exercise testing (CPET) to assess the link between CRF, PA and atrial remodelling assessed both invasively and non-invasively. Consecutive patients with symptomatic paroxysmal or persistent AF undergoing AF ablation were recruited. CRF was assessed objectively by measuring peak oxygen consumption (VO2PEAK) during CPET. Invasive assessment of atrial remodelling involved assessment of LA and RA electrical function using high-density electroanatomical maps and hemodynamic assessment of LA and RA pressures. Non-invasive assessment involved 2D transthoracic echocardiography at rest and during exercise. The association between VO2PEAK and atrial parameters were determined using multivariable linear regression models adjusted for age and sex. In total, 120 participants were recruited. Mean age was 63.2±11.2 and 74.5% of the cohort was male. In adjusted analyses, we observed a significant positive relationship between VO2PEAK and bipolar LA (p=0.049) and RA voltages (p=0.046). In addition, there was an inverse relationship between VO2PEAK and mean LAP (p<0.001) and mean RAP (p=0.013). On non-invasive testing, VO2PEAK was positively associated with left atrial emptying fraction (LAEF) (p=0.001) and reservoir strain (p<0.001) at rest. During exercise, VO2PEAK remained associated with LAEF (p<0.001) and LA reservoir strain (p=0.007). In patients with symptomatic AF, poor CRF is independently associated with extensive atrial remodelling involving LA and RA electrical remodelling, impaired LA haemodynamics, and LA mechanical dysfunction.

Prevalence and Characteristics of Inspiration-Induced Negative Left Atrial Pressure during Pulmonary Vein Isolation.

Atrial fibrillation (AF) ablation is performed under deep sedation, which may cause inspiration-induced negative left atrial pressure (INLAP) associated with deep inspiration. INLAP could be the cause of periprocedural complications. We retrospectively enrolled 381 patients with AF (mean age, 63.9 ± 10.8 years; 76 women; 216 cases of paroxysmal AF) who underwent CA under deep sedation using an adaptive servo ventilator (ASV). Patients whose LAP was not obtained were excluded. INLAP was defined as <0 mmHg of mean LAP during inspiration immediately after the transseptal puncture. The primary and secondary endpoints were the presence of INLAP and the incidence of periprocedural complications. Among 381 patients, INLAP was observed in 133 (34.9%). Patients with INLAP had higher CHA2DS2-Vasc scores (2.3 ± 1.5 vs. 2.1 ± 1.6) and 3% oxygen desaturation indexes (median 18.6 (interquartile range 11.2-31.1) vs. 15.7 (8.1-25.3)), and higher prevalence of diabetes mellitus (23.3 vs. 13.3%) than patients without INLAP. Air embolism occurred in four patients with INLAP (3.0 vs. 0.0%). INLAP is not rare in patients undergoing CA for AF under deep sedation with ASV. Much attention should be paid to the possibility of air embolism in patients with INLAP.

Impact of chronic mitral regurgitation on 3D atrial size and mechanics. Insights from the prospective 3D-PRIME study

Abstract Background Chronic mitral regurgitation (MR) leads to progressive left atrial (LA) dilation. Its relative contribution to 3-dimensional (3D) LA structural and functional remodelling and the impact of concomitant clinical and hemodynamic factors, has been less explored. Aims To assess 3D LA size and mechanics, as well as mean LA pressure estimated from the pulmonary vein flow, in relation to chronic MR severity. Methods In the prospective 3D-PRIME (3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation) study, 46 patients with chronic MR (69±13 years, body mass index (BMI) 26.2±4.3kg/m2, 50% women, 26% with atrial fibrillation, 30% with severe MR) recruited at one heart valve center were investigated with 2D and 3D transthoracic and transesophageal echocardiography. MR severity was quantified by the regurgitant volume (RV) and MR classified as organic, atrial functional or ventricular functional, as by current recommendations. LA size was measured by 3D maximum volume (LAV) indexed for body surface area (LAVI), LA mechanics by 3D peak relative increase in longitudinal volume in the reservoir phase (Sr), and mitral size by 3D annulus area and total leaflet area. Pulmonary vein Doppler flow profile was recorded in both right and left upper veins, and mean LA pressure was estimated from the average pulmonary vein systolic/diastolic velocity time integral ratio. Results Average mitral RV was 38±26ml, LAVI 53ml/m2, and Sr 17±11%. Increased mitral RV correlated with higher LAV and mean LA pressure (Figure 1), larger mitral annulus area (r=0.42) and total leaflet area (r=0.38) (all p&amp;lt;0.01), but not with Sr. In backward stepwise multivariate linear regression analyses, increased LAVI was independently predicted by larger mitral RV, higher age and atrial fibrillation (R2=0.62), higher mean LAP by larger mitral RV, body mass index and atrial fibrillation (R2=0.55), while lower Sr was associated with higher age and atrial fibrillation (R2=0.62) (all p&amp;lt;0.001). Patients with atrial functional MR (30% of the total group) had the largest LAVs and lowest Sr despite slightly lower mitral RV (Figure 2). Conclusion Chronic MR is associated with progressive increase in LA volume, mean LA pressure, and mitral annulus and total leaflet area. While MR is accompanied by low 3D LA longitudinal deformation, impaired LA mechanics is multifactorial and related closely to age and history of atrial arrythmias. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Haukeland University Hospital Figure 1Figure 2

Echocardiographic assessment of left ventricular filling pressure in patients with acute ST elevation myocardial infarction: an invasive validation study.

Backgrounds Assessment of left ventricular filling pressure (LVFP) is of clinical importance in patients with ST elevation myocardial infarction (STEMI). Although several echocardiographic parameters are recommended for the assessment of LVFP, validation of these parameters in patients with STEMI is missing. We aimed to investigate the clinical utility of these parameters in acute settings. Methods: We prospectively included consecutive patients with STEMI. LV end-diastolic pressure (LVEDP) was measured following primary PCI and echocardiographic examination was performed within 24 hours. Mean left atrial pressure (mLAP) was calculated both invasively using Yamamoto's formula and non-invasively using Naugeh's formula. Mean LAP was considered increased when exceeded 18mmHg. Results: Patients were grouped according to LVEDP, group 1(41 patients) and group 2(114 patients).There was no significant difference between groups in terms of comorbidities. NT pro-BNP levels (p < 0.001) and peak level of Hs-TnT (p-value: 0.002) were significantly higher in group 2. Average E/e' ratio was significantly higher in group 2 (10.19 ± 3.15 vs. 12.04 ± 4.83, p: 0.046). Isovolumetric relaxation time was longer in group 2 (p < 0.001) and left atrial volume index (LAVI) was also significantly higher in group 2 (p < 0.001). Regression analyses revealed that septal, lateral and average E/e' ratio, tricuspid regurgitation velocity, LAVI and left ventricular volume are correlated with mLAP. Among group 2 patients only 14 Patients fulfilled the increased LVFP criteria suggested by current guidelines. Conclusions Echocardiographic parameters indicating increased LVFP require validation and may need to be modified in patients with STEMI. Moreover, current algorithms underestimate the actual number of patients with increased LVFP.

Assessment of Ultrasound -Guided Core Needle Biopsy as the First-Line Diagnostic Procedure for Cervical Lymphoma

Objective: This study was conducted to assess the effectiveness of Ultrasound-guided Core Needle Biopsy (US-CNB) to provide sufficient information for diagnosis and initiation of the treatment for head and neck lymphoma.Study Design: We carried out the prospective consecutive case series in a single- center study.Setting: The tertiary medical center setting.Patients and Methods: Totally, 72 patients were enrolled and the US-CNB of suspicious cervical lymph node was performed. Demographics, imaging and pathological data were collected for each patient and used to identify the factors that shape the diagnostic yield of US-CNB.Results: We observed among 72 CNBs 52 were fully diagnosed and 20 cases needed Excisional Surgical Biopsy for sub-classification. Then the factors influencing the results of the US-CNB, as the first-line diagnostic procedure for suspected cervical lymphadenopathy were discussed. The CNB results did not differ in terms of BMI, neck circumference and pathological subtype. Fully diagnosis CNB results demonstrated an association with higher mean tumor size and LAP in cervical zones 1 to 4 rather than posterior triangle.Conclusion: About 30% of the patients in the present study required ESB after US-CNB for fully diagnosis and this delayed their treatment. Therefore, the use of US-CNB as a primary method in assessment of cervical lymphadenopathy still needs more studies to investigate the factors influencing the results and shaping its diagnostic yield.

Introduction, interpretation and reliability of a simple wingate based modified field running test to assess anaerobic capacity (of female soccer players in Germany and the United States of America)

Introduction: In team sports with short repeated sprints and changes of direction, it is important to know how the anaerobic capacity level of his players is and develops during the season. To test this ability the 15m Modified Shuttle Run Test (15m MSRT), based on the Wingate Cycle Test principles, was developed. Method: Two groups of five female soccer players from Germany (GER) (average age 19.2 years; range 18–21) and the United States of America (US), (average age 18.8 years; range 17–21) performed a 15m MSRT on two occasions to test the reliability. Maximum (Highest Lap Velocity (HLV)), minimum (Lowest Lap Velocity (LLV)) and average speed (Mean (Individual) Velocity (M(I)V)) of the individual player and average lap speed (Mean Lap Velocity (M(L)V)), the Fitness Index (FiI), Fatigue Index (FaI) and Speed–Endurance–Index (SEI) was calculated for the individual player as well as for the whole team. Results: The ICC and CV for the MLV was 0.95 and 1.41% resp (GER) and 0.72 and 3.24% (US), the Fitness Index (GER: 0.93 and 2.90%; USA: 0.78 and 4%) and Speed–Endurance–Index (GER: 0.95and 3.30%; US: 0.94 and 4.40%) Conclusion and recommendation: The 15m MSRT is a reliable tool to assess and monitor both individual and team running speed. The MIV is useful to individualize anaerobic capacity training.

Laser welding of carbon fibre filled polytetrafluoroethylene

Herein, a method is described to weld polytetrafluoroethylene (PTFE), a non-melt processable thermoplast, using a thulium laser. Different settings for laser power and speed were used. The resulting mean lap shear strength per setting ranged from 0.081 N/mm² to 0.297 N/mm². The optimal setting was found to be 12 W irrespective of the welding speed applied. Micro-computed tomography (μ-CT) and optical microscopy was used to show that the welded pattern consisted of tunnel defects. As PTFE is known to be non-melt processable, a physico-chemical characterization was performed to examine the formation of degradation products. Differential scanning calorimetry (DSC) showed a reduction in molecular weight of the PTFE in the weld pattern after welding. Attenuated total reflectance infrared (ATR-IR) and nuclear magnetic resonance (NMR) spectroscopy using hexafluoroisopropanol (HFIP) did not indicate the presence of any new compounds in the respective spectra.

Regression-based analysis of front crawl swimming using upper-arm mounted accelerometers.

Wearable accelerometers can be used to quantify movement during swimming, enabling objective performance analysis. This study examined arm acceleration during front crawl swimming, and investigated how accelerometer-derived features change with lap times. Thirteen participants swam eight 50m laps using front crawl with a tri-axial accelerometer attached to each upper arm. Data were segmented into individual laps; lap times estimated and individual strokes extracted. Stroke times, root mean squared (RMS) acceleration, RMS jerk and spectral edge frequencies (SEF) were calculated for each stroke. Movement symmetry was assessed as the ratio of the minimum to maximum feature value for left and right arms. A regularized multivariate regression model was developed to estimate lap time using a subset of the accelerometer-derived features. Mean lap time was 56.99±11.99s. Fifteen of the 42 derived features were significantly correlated with lap time. The regression model included 5 features (stroke count, mean SEF of the X and Z axes, stroke count symmetry, and the coefficient of variation of stroke time symmetry) and estimated 50m lap time with a correlation coefficient of 0.86, and a cross-validated RMS error of 6.38s. The accelerometer-derived features and developed regression model may provide a useful tool to quantitatively evaluate swimming performance.

Dehydration Has No Influence on Simulated Motor-race Performance Despite Greater Cardiovascular and Thermoregulatory Demand

Purpose: Motor-racing drivers compete in hot compensable environments imposing high physiological strain. Dehydration may impact a driver’s health, safety and race performance. This study examined the effect of heat-induced dehydration on performance and physiological outcomes during a simulated motor-race. Methods: Fifteen healthy men [age: 25.2±5.4 y, body mass: 84.8±10.7 kg, VIO2peak: 43.7±7.8 mL.kg-1.min-1 (mean±SD)] participated in this controlled crossover study. Participants were randomised (counter-balanced) to a no fluid trial [1.9±0.1% body mass loss (BML) via sauna exposure (wet bulb globe temperature (WBGT): 43.6±2.8°C)] and fluid trial [1.0±0.5% body mass gain via room temperature water consumption every 10 min during sauna exposure]. All participants completed ˜60 min of Australian simulated motor-racing in a heated (WBGT: 33.7±0.7°C) laboratory with no fluid provided to both trials which resulted in a 1.3±0.4 and 0.9±0.2% BML for the fluid and no fluid trials respectively. Lap time, physiological strain, heart rate and core/skin temperature were measured throughout the task. Urine [specific gravity (USG) and osmolality (Uosm)], body mass, and serum [sodium (Na), osmolality (Sosm), and plasma volume (PV)] samples were collected pre- and post- sauna and race. Results: Mean lap time was not different between trials (fluid=134.981±2.402 s, no fluid=134.718±2.147 s; p=0.293). The no fluid trial resulted in significantly higher (p<0.05) peak heart rate (129±16 vs. 121±16 beats.min-1), core temperature (38.0±0.2 vs. 37.7±0.3°C), physiological strain (4.1±1.1 vs. 3.5±1.1), Sosm (310±4 vs. 300±4 mOsm.kg-1), Na (138.7±2.1 vs. 135.8±4.5 mmol.L-1), USG [median(interquartile range): 1.025(1.024-1.027) vs. 1.006(1.004-1.013)], Uosm [942(879-1010) vs. 221(186-497) mOsm.kg-1], total body mass loss (2.7±0.3 vs. 0.9±0.4%) and change in PV (-7.9±4.2 vs. -3.3±4.2 %) than the fluid trial. Conclusion: Dehydration of ˜2.7% BML without fluid replacement had no influence on simulated race performance measured by mean lap time, despite significantly greater cardiovascular and thermoregulatory demand. Further research is warranted to assess the impact of greater cardiovascular and thermoregulatory demand from dehydration on the safety, health and well-being of drivers.

Robotic colectomy with intracorporeal anastomosis is feasible with no operative conversions during the learning curve for an experienced laparoscopic surgeon developing a robotics program.

The benefits of performing a colectomy robotically instead of laparoscopically have not conclusively been demonstrated. Evaluation of studies is limited by sample size, retrospective design, heterogeneity of operative techniques, sparse adjustment for learning curve, and mixed results. Consequently, adoption of robotic colectomy by surgeons has been expectedly slow. The objectives of the study were to compare the outcomes of robotic colectomy to laparoscopic colectomy for patients with right-sided tumors undergoing a standardized completely intracorporeal operation and to examine the impact of prior experience with laparoscopic right colectomies on the performance of robotic right colectomies. Retrospective review of outcomes of consecutive patients undergoing a robotic right colectomy (robot) compared to those undergoing laparoscopic colectomy (LAP). LAP patients were further subdivided into a group during the learning curve (LC) and after the learning curve (post-LC). Data collected included operative time (OT), conversion to laparotomy, lymph nodes harvested (LN), length of stay (LOS), 30-day morbidity, and mortality. Comparison of continuous and categorical variables was assessed with the independent samples t test and Chi-square test, respectively. Data are expressed as mean ± SD, and significance defined as p < 0.05. 122 patients underwent robot (n = 21), LAP (n = 101), LC (n = 51), or post-LC (n = 50). OT was decreased for post-LC compared to LC (198 vs. 228min). There were no conversions in robot and five with LAP. Morbidity was similar for robot (14%) compared to LAP (22%), LC (24%), or post-LC cases (20%). Median LOS was similar for robot vs. LAP (3 vs. 5 days). Robot had greater mean LN yield vs. LAP (19 vs. 14, p = 0.02). The initial outcomes with completely intracorporeal colectomy achieved robotically were equivalent to results during or after LC for laparoscopic resection. Proficiency gained with LAP seems to positively impact the initial results with the robot.

Lap Time Variation Predicts Task Error During Dual-Task Walking In Cognitively Healthy Women

Variation in lap time (LTV) during a fast pace 400m walk test is a new metric thought to be an early indicator of cognitive decline in older adults. While LTV has been found to associate with executive function, no study has examined the potential for LTV to predict capacity of the brain to divide attention and meet the demand of walking and performing other tasks simultaneously. PURPOSE: The purpose of this study was to test the hypothesis that greater LTV would associate with larger dual-task cost during walking. METHODS: Fifty-two cognitively healthy (MoCA>25) women across a broad age range (30-80y) performed fast pace walking while balancing a tray (Dual1) or balancing a tray while vocalizing serial subtractions by 7’s (Dual2). Task error was quantified by degrees of tray tilt and subtraction error. On a separate day, women completed a fast pace 400m walk test (40m x 10 laps) with time to complete each lap recorded. LTV was defined as standard deviation of residuals estimated from the random effects linear model where each lap time was regressed on a person-specific random intercept and random slope associated with lap. Women were categorized into tertiles based on LTV. Comparisons were made between tertiles using ANCOVA after adjusting for age, years of education, and mean lap time. RESULTS: Gait speed (p=0.57) or the percent change in gait speed (p=0.34) were not significantly different between tertiles for the Dual1 condition, but tilt angle was larger in women with greater LTV (tertiles 1 vs. 3: 1.37±0.12 vs. 1.94±0.11 degrees; p=0.006). During the Dual2 condition, women with greater LTV had faster gait speed (p=0.02), lower percent change in gait speed (tertiles 1 vs. 3: 20.5±2.8 vs. 9.3±2.6%, p=0.02), similar subtraction error (p=0.58), but larger tilt angle (tertiles 1 vs. 3: 1.24±0.19 vs. 2.09±0.17 degrees, p=0.007). CONCLUSION: Lap time variation identified women that exhibited greater difficulty balancing an object while walking suggesting that LTV may be sensitive to deficits in the ability to share neural substrate for sensorimotor function. Supported by a Women’s Health Research Scholar Grant award from the Laura W. Bush Institute of Women’s Health and University Medical Center in Lubbock, TX.

The Effect of "Pumping" and "Nonpumping" Techniques on Velocity Production and Muscle Activity During Field-Based BMX Cycling.

Rylands, LP, Hurst, HT, Roberts, SJ, and Graydon, RW. The effect of "pumping" and "nonpumping" techniques on velocity production and muscle activity during field-based BMX cycling. J Strength Cond Res 31(2): 445-450, 2017-The aim of the current study was to determine if a technique called "pumping" had a significant effect on velocity production in Bicycle Motocross (BMX) cycling. Ten National standard male BMX riders fitted with surface electromyography (sEMG) sensors completed a timed lap of an indoor BMX track using the technique of pumping, and a lap without pumping. The lap times were recorded for both trials and their surface sEMG was recorded to ascertain any variation in muscle activation of the biceps brachii, triceps brachii, vastus lateralis, and medial gastrocnemius. The findings revealed no significant differences between any of muscle groups (p > 0.05). However, significant differences (p < 0.001) were observed between the pumping and nonpumping trials for both mean lap velocity (42 ± 1.8 km·h, 33 ± 2.9 km·h, respectively) and lap times (43.3 ± 3.1 seconds, 34.7 ± 1.49 seconds, respectively). The lap times recorded for the pumping trials were 19.50 ± 4.25% lower than the nonpumping, whereas velocity production was 21.81 ± 5.31% greater in the pumping trial compared with the nonpumping trial. The technique of pumping contributed significantly to velocity production, although not at the cost of additional muscle activity. From a physiological and technical perspective, coaches and riders should prioritize this technique when devising training regimes.

Lower gray matter integrity is associated with greater lap time variation in high-functioning older adults

BackgroundLower integrity of cerebral gray matter is associated with higher gait variability. It is not known whether gray matter integrity is associated with higher lap time variation (LTV), a clinically accessible measure of gait variability, high levels of which have been associated with mortality. This study examines the cross-sectional association between gray matter mean diffusivity (MD) and LTV in community-dwelling older adults. MethodsStudy participants consisted of 449 high-functioning adults aged 50 and older (56.8% female) in the Baltimore Longitudinal Study of Aging, free of overt neurological disease. The magnitude of MD in the gray matter, a measure of impaired tissue integrity, was assessed by diffusion tensor imaging in 16 regions of interest (ROIs) involved with executive function, sensorimotor function, and memory. LTV was assessed as variability in lap time based on individual trajectories over ten 40-m laps. Age, sex, height, and weight were covariates. The model additionally adjusted for mean lap time and health conditions that may affect LTV. ResultsHigher levels of average MD across 16 ROIs were significantly associated with higher LTV after adjustment for covariates. Specifically, higher MD in the precuneus and the anterior and middle cingulate cortices was strongly associated with higher LTV, as compared to other ROIs. The association persisted after adjustment for mean lap time, hypertension, and diabetes. ConclusionsLower gray matter integrity in selected areas may underlie greater LTV in high-functioning community-dwelling older adults. Longitudinal studies are warranted to examine whether changes in gray matter integrity precede more variable gait.

Correlation of pulmonary capillary wedge pressure with left atrial pressure in patients with mitral stenosis undergoing balloon valvotomy

AimsWe sought to evaluate the correlation between PCWP and LAP and to compare transmitral gradients obtained with LAP and PCWP in MS, before and after balloon mitral valvotomy (BMV). MethodsConsecutive patients with MS for BMV were included in this prospective cohort study. Simultaneous PCWP and LAP were recorded followed by simultaneous left atrium–left ventricular (LA–LV) and pulmonary capillary wedge pressure–left ventricular (PCWP–LV) gradients before and after BMV. ResultsThere were 30 patients with a mean age of 41 yrs (males 10 (33.3%), females 20 (66.7%)). There was no significant difference between mean LAP and mean PCWP before BMV (21.3mmHg and 22.3mmHg, respectively) or after BMV (15.3mmHg and 17.3mmHg, respectively). There was excellent correlation between mean PCWP and mean LAP before BMV (r=0.95) (p<0.001) and after BMV (r=0.85) (p<0.001). The phasic components of the pressures (a and v waves) of LAP and PCWP also showed good correlation before and after BMV. Further, transmitral gradients assessed by LA–LV and PCWP–LV pressures showed excellent correlation before BMV (r=0.95) (p<0.001) and after BMV (r=0.95) (p<0.001). ConclusionIn patients with MS undergoing balloon valvotomy, PCWP shows good correlation with LAP. Transmitral gradients obtained with PCWP and LAP also correlate well after correction of phase lag in PCWP tracing. Hence, PCWP can be used for reliable measurement of transmitral gradient.

Driving with a short arm cast in a simulator.

To test the ability to steer in a driving simulator in subjects with a short arm cast. 17 men and 13 women aged 23 to 67 (mean, 37) years who had a valid driver's licence were randomised to the cast-first group (n=16; 7 had the cast on the dominant arm) or the cast-second group (n=14; 8 had the cast on the dominant arm) and drove in a simulator. A short arm plaster-of-Paris cast was applied in a neutral position, allowing free movement of the metacarpophalangeal joints, thumb, and elbow joint. Outcome measures included the number of driving off track instances, the number of crashes, the lap time, and the effect of hand dominance on these parameters. Subjects were asked whether the cast had impeded their steering ability. Subjects with or without a cast were comparable in terms of the number of driving off track instances, number of crashes, and lap time. Compared with no cast, the odds ratio (OR) of a subject in a cast driving off the track was 1.02 (p=0.921) and having a crash was 0.79 (p=0.047). All subjects were 1.23 times more likely to drive off the track in their first lap (OR=2.66, p=0.019). The mean lap time decreased for each consecutive lap from the 2nd to 5th laps. Subjects driving with a cast on the dominant or non-dominant arm were comparable. 26 out of the 30 participants considered that the plaster cast impeded their steering ability. Compared with no cast, driving with a short arm cast did not significantly decrease steering ability in a driving simulator.

Intra-individual lap time variation of the 400-m walk, an early mobility indicator of executive function decline in high-functioning older adults?

Higher intra-individual lap time variation (LTV) of the 400-m walk is cross-sectionally associated with poorer attention in older adults. Whether higher LTV predicts decline in executive function and whether the relationship is accounted for by slower walking remain unanswered. The main objective of this study was to examine the relationship between baseline LTV and longitudinal change in executive function. We used data from 347 participants aged 60 years and older (50.7% female) from the Baltimore Longitudinal Study of Aging. Longitudinal assessments of executive function were conducted between 2007 and 2013, including attention (Trails A, Digit Span Forward Test), cognitive flexibility and set shifting (Trails B, Delta TMT: Trials B minus Trials A), visuoperceptual speed (Digit Symbol Substitution Test), and working memory (Digit Span Backward Test). LTV and mean lap time (MLT) were obtained from the 400-m walk test concurrent with the baseline executive function assessment. LTV was computed as variability of lap time across ten 40-m laps based on individual trajectories. A linear mixed-effects model was used to examine LTV in relation to changes in executive function, adjusted for age, sex, education, and MLT. Higher LTV was associated with greater decline in performance on Trails B (β = 4.322, p < 0.001) and delta TMT (β = 4.230, p < 0.001), independent of covariates. Findings remained largely unchanged after further adjustment for MLT. LTV was not associated with changes in other executive function measures (all p > 0.05). In high-functioning older adults, higher LTV in the 400-m walk predicts executive function decline involving cognitive flexibility and set shifting over a long period of time. High LTV may be an early indicator of executive function decline independent of MLT.

The effect of age and microstructural white matter integrity on lap time variation and fast-paced walking speed.

Macrostructural white matter damage (WMD) is associated with less uniform and slower walking in older adults. The effect of age and subclinical microstructural WM degeneration (a potentially earlier phase of WM ischemic damage) on walking patterns and speed is less clear. This study examines the effect of age on the associations of regional microstructural WM integrity with walking variability and speed, independent of macrostructural WMD. This study involved 493 participants (n = 51 young; n = 209 young-old; n = 233 old-old) from the Baltimore Longitudinal Study of Aging. All completed a 400-meter walk test and underwent a concurrent brain MRI with diffusion tensor imaging. Microstructural WM integrity was measured as fractional anisotropy (FA). Walking variability was measured as trend-adjusted variation in time over ten 40-meter laps (lap time variation, LTV). Fast-paced walking speed was assessed as mean lap time (MLT). Multiple linear regression models of FA predicting LTV and MLT were adjusted for age, sex, height, weight, and WM hyperintensities. Independent of WM hyperintensities, lower FA in the body of the corpus callosum was associated with higher LTV and longer MLT only in the young-old. Lower FA in superior longitudinal, inferior fronto-occipital, and uncinate fasciculi, the anterior limb of the internal capsule, and the anterior corona radiate was associated with longer MLT only in the young-old. While macrostructural WMD is known to predict more variable and slower walking in older adults, microstructural WM disruption is independently associated with more variable and slower fast-paced walking only in the young-old. Disrupted regional WM integrity may be a subclinical contributor to abnormal walking at an earlier phase of aging.

LAP (produto da acumulação lipídica) e síndrome metabólica em pacientes com síndrome dos ovários policísticos

IntroductionPolycystic Ovary Syndrome (SOP) is a common endocrine disorder that affects 5‐10% of women of reproductive age. The association between metabolic syndrome and changes related to glucose and insulin is frequent in patients with SOP, increasing the cardiovascular risk of these patients. The LAP is an emerging cardiovascular risk based on the combination of waist circumference (WC) and triglycerides (TGL) and fasting simply reflects the lipid accumulation in adults. ObjectivesThis study examined the possible correlation between metabolic syndrome or LAP and reproductive and metabolic parameters in patients with SOP. Materials and MethodsThe study included two hundred ninety‐nine patients with SOP, defined by the Rotterdam criteria followed at HC‐UFMG who had assessed their levels of triglycerides, total testosterone, fastingand two hours after 75 grams of overload dextrosol (GPD), TSH, LAP, Ferriman index, ovarian volume and abdominal circumference, and the presence or absence of metabolic syndrome. ResultsThe mean LAP was 60.9 and the median 51.3. Patients with and without metabolic syndrome when compared to each others howed no differences in ovarian volume, total testosterone, Ferriman, fastingand post‐dextrosol. Women with metabolic syndrome had higher TSH levels than women without metabolic syndrome. The women in the top quartile of the LAP had TSH, Ferriman and GPD higher than women in the lower quartiles of LAP. ConclusionsThe higher values of LAP suggested good correlation of this index with insulin resistance. TSH levels were higher in patients with metabolic syndrome and LAP in the top quartile in SOP patients represent a new element in the literature and needs to be better studied.

Lap time variation and executive function in older adults: the Baltimore Longitudinal Study of Aging.

poor cognitive and motor performance predicts neurological dysfunction. Variable performance may be a subclinical indicator of emerging neurological problems. examine the cross-sectional association between a clinically accessible measure of variable walking and executive function. older adults aged 60 or older from the Baltimore Longitudinal Study of Aging (n = 811) with data on the 400-m walk test and cognition. Based on ten 40-m laps, we calculated mean lap time (MLT) and variation in time across ten 40-m laps (lap time variation, LTV). Executive function tests assessed attention and short-term memory (digit span forward and backward), psychomotor speed [Trail Making Test (TMT) part A] and multicomponent tasks requiring cognitive flexibility [TMT part B, part B-A (Delta TMT) and digit symbol substitution test (DSST)]. Multivariate linear regression analysis examined the cross-sectional association between LTV and executive function, adjusted for MLT, age, sex and education, as well as the LTV × MLT interaction. the LTV was univariately associated with all executive function tests except digit span (P < 0.001); after adjustment, the association with TMT part A remained (standardised β = 0.142, P = 0.002). There was an interaction between MLT and LTV; among fast walkers, greater LTV was associated with a greater Delta TMT (β for LTV × MLT = -1.121, P = 0.016) after adjustment. at any walking speed, greater LTV is associated with psychomotor slowing. Among persons with faster walking speed, variation is associated with worse performance on a complex measure of cognitive flexibility. A simple measure of variability in walking time is independently associated with psychomotor slowing.

Investigating Forward Velocity and Symmetry in Freestyle Swimming Using Inertial Sensors.

Investigating the performance of an athlete and monitoring them is important to athletes and coaches because it can provide information about the training progress and injury recovery. Coaches are not always on side when athletes doing their training, so a device which is small and easy to use will increase the monitored training sessions significantly and allow the athlete to compare multiple training sessions. This technology has seen rapid development over the last years and is now available in very small sizes which have little effect on the swimmer. Using this kind of sensor, kinematics can be measured and extracted for stroke characteristics investigations. This research used an sacrum mounted self-developed inertial sensor, providing a triaxial accelerometer, gyroscope and RF capability in a waterproof casing to investigate the arm symmetry and swimming velocity in freestyle swimming. The recorded data were filtered using a high-pass Hamming windowed FIR filter to remove the gravity components from the wanted signal. The acceleration signal was then processed to find the velocity of the swimmer. A zero-crossing detection algorithm was used to investigate the arm symmetry and to find the individual stroke rates (SR), the differences between left and right arm stroke durations and the left and right arm stroke velocities (asymmetry). The investigation of the left and right arm velocity patterns of each individual swimmer allowed the investigation of each swimmers asymmetry in propulsion and velocity for the individual arms. The results of the mean lap velocities showed that the two different methods agree with an R2 of 0.92. Furthermore a conducted Bland-Altman analysis showed a low bias of -0.04 with an upper limit of agreement of 0.03 and a lower limit of agreement of -0.11.