Effect of calendar age on physical performance: A comparison of standard clinical measures with instrumented measures in middle-aged to older adults

BackgroundDecline in physical performance is highly prevalent during aging. Identification of sensitive markers of age-related changes in physical performance is important for early detection, development of therapeutic strategies and insight into underlying mechanisms. We studied the association of calendar age and familial longevity with standard clinical and instrumented measures of physical performance in a cohort of healthy middle-aged to older adults.MethodsCross-sectional analysis within the Leiden Longevity Study consisting of offspring of nonagenarian siblings and their partners (n = 300, mean age (SD) 65.3 (6.7) years). Standard clinical measures were 25-meter walking speed and total duration of the chair stand test (CST). Instrumented measures were determined using a body fixed sensor. Dependence of physical performance on calendar age and familial longevity (offspring versus partner status) was analyzed using linear and logistic regression, respectively, adjusted for gender and height.ResultsHigher calendar age was associated with slower walking speed and longer duration of the CST (standardized β (95% CI) −.024 (−.042; −.006) and .035 (.014;.056), respectively). Instrumented measures showed similar effect sizes with strongest associations for gait stability and symmetry in mediolateral direction and for the extension and flexion phase of sit-to-stand and stand-to-sit transfers, respectively. No differences were observed between offspring of nonagenarian siblings and their partners.ConclusionsStandard clinical and instrumented measures of physical performance are associated with similar effect size to age-related changes in physical performance observable from middle age. The potential added value of instrumented measures for understanding underlying mechanisms requires further attention.     

The transition between turning and sitting in patients with Parkinson's disease: A wearable device detects an unexpected sequence of events

BackgroundWhen older adults turn to sit, about 80% of the subjects complete the turn before starting to sit i.e., a distinct-strategy, while in about 20%, part of the turning and sitting take place concurrently, i.e., an overlapping-strategy. A prolonged duration of the separation between tasks in the distinct-strategy (D-interval) and a prolonged duration of the overlap interval in overlapping-strategy (O-interval) are related to worse motor symptoms and poorer cognition. In the present study, we evaluated what strategy is employed by patients with Parkinson’s disease (PD) when they transition from turning to sitting.Methods96 participants with PD performed turn to sit as part of the Timed Up and Go test, both with and without medications, while wearing a body-fixed sensor. We quantified the turn-to-sit transition and determined which strategy (distinct or overlapping) was employed. We then stratified the cases and used regression models adjusted for age, gender, height, and weight to examine the associations of the D-interval or O-interval with parkinsonian features and cognition.ResultsMost patients (66%) employed the overlapping-strategy, both off and on anti-parkinsonian medications. Longer O-intervals were associated with longer duration of PD, more severe PD motor symptoms, a higher postural-instability-gait-disturbance (PIGD) score, and worse freezing of gait. Longer D-intervals were not associated with disease duration or PD motor symptoms. Neither the D- nor O-intervals were related to cognitive function. Individuals who employed the overlapping-strategy had more severe postural instability (i.e., higher PIGD scores), as compared to those who used the distinct-strategy.SignificanceIn contrast to older adults without PD, most patients with PD utilize the overlapping strategy. Poorer postural and gait control are associated with the strategy choice and with the duration of concurrent performance of turning and sitting. Additional work is needed to further explicate the mechanisms underlying these strategies and their clinical implications.     

Activity trackers are not valid for step count registration when walking with crutches

BackgroundThe use of activity trackers has been proposed in rehabilitation where resuming physical activity is deemed crucial, e.g. after total knee arthroplasty (TKA). As patients initially often walk with crutches, it is of importance that clinicians can rely on the information provided by activity trackers.Research questionTo determine concurrent validity of 2 activity trackers for step count, positioned on different locations on the body during gait with crutches.MethodsThirty healthy participants performed normal gait and gait with one crutch and two crutches over a distance of 400 m while wearing a Garmin Vivofit 3 and Nokia Go on both wrists and both sides at the waist (only Nokia Go). The gold standard was manual step count. Inter-device reliability (within brand) was assessed by calculating Intraclass Correlation Coëfficients (ICC) and concurrent validity was determined by performing paired sample t-tests, ICC and Bland-Altman Plots with % bias and 95% CI Limits of Agreement (LoA).ResultsDuring normal gait, both the Nokia and Garmin showed good to excellent inter-device reliability (ICC > 0.75). Both devices showed concurrent validity compared to manual step count, with slightly better results for the Garmin compared to the Nokia at the wrist (% bias = respectively 0.0% and -1.4% with 95% CI LoA: respectively -1.7%;1.7% and -8.6%;5.8%; ICC: respectively 0.995 and 0.859). During gait with crutches, however, overall 95% CI of LoA were beyond clinically acceptable differences and ICC values with the gold standard were poor. Therefore, notwithstanding a sometimes reported small average % bias, validity of the activity trackers for step count during gait with crutches was not established, independent of tracker position.SignificanceActivity trackers showed no concurrent validity when monitoring step count during gait with crutches. This should be taken into account when implementing this technology in e.g. post-operative goal setting in patients with TKA.     

Metal on Metal Hip Resurfacing in Patients 45 Years of Age and Younger at Minimum 5-Year Follow-Up

Background

Metal on metal hip resurfacing (MoM-HR) is an alternative to total hip arthroplasty in young and active patients. The purpose was to determine the survivorship of MoM-HR procedures performed in patients aged 45 years and younger assessing patient-reported outcome measures (PROMs) at minimum 5-year follow-up.

Consistency of gait characteristics as determined from acceleration data collected at different trunk locations

Estimates of gait characteristics may suffer from errors due to discrepancies in accelerometer location. This is particularly problematic for gait measurements in daily life settings, where consistent sensor positioning is difficult to achieve. To address this problem, we equipped 21 healthy adults with tri-axial accelerometers (DynaPort MiniMod, McRoberts) at the mid and lower lumbar spine and anterior superior iliac spine (L2, L5 and ASIS) while continuously walking outdoors back and forth (20 times) over a distance of 20 m, including turns. We compared 35 gait characteristics between sensor locations by absolute agreement intra-class correlations (2, 1; ICC). We repeated these analyses after applying a new method for off-line sensor realignment providing a unique definition of the vertical and, by symmetry optimization, the two horizontal axes. Agreement between L2 and L5 after realignment was excellent (ICC > 0.9) for stride time and frequency, speed and their corresponding variability and good (ICC > 0.7) for stride regularity, movement intensity, gait symmetry and smoothness and for local dynamic stability. ICC values benefited from sensor realignment. Agreement between ASIS and the lumbar locations was less strong, in particular for gait characteristics like symmetry, smoothness, and local dynamic stability (ICC generally < 0.7). Unfortunately, this lumbar-ASIS agreement did not benefit consistently from sensor realignment. Our findings show that gait characteristics are robust against limited repositioning error of sensors at the lumbar spine, in particular if our off-line realignment is applied. However, larger positioning differences (from lumbar positions to ASIS) yield less consistent estimates and should hence be avoided.     

���ϵ�-ѹ�紫�м���Ƕ�ĥ��֢�����������о�

目的 研制出检测磨牙症牙合力的牙合垫-压电传感检测仪，为临床上诊断磨牙症提供一种新的手段。方法 以聚偏氟乙烯（PVDF）压电膜为传感元件，运用电阻应变传感技术，结合大规模集成电路和液晶数字显示系统等，对10名正常受试者模拟磨牙运动的最大牙合力进行检测，并对测量结果采用随机区组方差分析。结果 仪器的最大误差范围±0.2235 kgf，组内相关系数（ICC）0.9998。证明此牙合垫-压电传感检测仪的测量误差较小，测量重复性好。结论 此仪器能够真实地记录模拟磨牙运动时牙合垫表面加载力的大小，可以满足临床对磨牙症牙合力进行检测的应用。     

超声雾化器使用不当引起的非零件损坏故障分析及处理

超声雾化器是临床广泛使用的医疗仪器，由于使用频率高、使用人员多使其故障发生率也很高，但其中，因使用人员对仪器使用保养不当而引起的非真正的机器内部零件损坏，机器却不能正常使用而报设备科修理的故障亦很常见，使用人员完全可以自已解决或避免此类故障再次发生。本文着重就此原因引起的一些超声雾化器故障，分析原因、找出解决处理方法。     

基于单片机的睡眠定时实验装置

本文介绍基于单片机的睡眠定时实验装置的系统设计、硬件电路设计和系统软件程序设计.系统调试和测试结果表明,该装置很好的满足了系统设计的功能要求.     

PB-840呼吸机气路系统工作原理

PB-840呼吸机在国内外医院广泛使用,本文详细介绍了 PB840的气路系统的结构及工作原理.