Long-term Tai Chi practice in older adults is associated with "younger" functional abilities.

Age-related alterations in physiology lead to declines in physical function that are associated with numerous adverse outcomes among older adults. Utilizing a hybrid design, we aimed to understand whether both long-term and short-term Tai Chi (TC) training are associated with age-related decline in physical function in healthy older adults. We first conducted cross-sectional comparisons among TC-naïve older adults (n = 60, 64.2 ± 7.7 years), TC-expert older adults (n = 27, 62.8 ± 7.6 years, 24.5 ± 12 years experience), and TC-naïve younger adults (n = 15, 28.7 ± 3.2 years) to inform long-term effects of TC training on physical function, including single leg stance time with eyes closed, grip strength, Timed Up and Go, maximum walking speed, functional reach, and vertical jump for lower-extremity power. There were significant differences among the three groups on all the six tests. For most functional tests, TC-experts performed better than age-matched TC-naïve controls and were statistically indistinguishable from young healthy adult controls. Long-term TC training was associated with higher levels of physical function in older adults, suggesting a potential preventative healthy aging effect. In the randomized longitudinal trial, TC-naïve subjects were randomized (n = 31 to Tai Chi group, n = 29 to usual care control group) to evaluate the short-term effects of TC over 6 months on all outcomes. TC's short-term impacts on physical function were small and not statistically significant. The impact of short-term training in healthy adults is less clear. Both potential longer-term preventive effects and shorter-term restorative effects warrant further research with rigorous, adequately powered controlled clinical trials.

MIMIC-IV, a freely accessible electronic health record dataset.

Digital data collection during routine clinical practice is now ubiquitous within hospitals. The data contains valuable information on the care of patients and their response to treatments, offering exciting opportunities for research. Typically, data are stored within archival systems that are not intended to support research. These systems are often inaccessible to researchers and structured for optimal storage, rather than interpretability and analysis. Here we present MIMIC-IV, a publicly available database sourced from the electronic health record of the Beth Israel Deaconess Medical Center. Information available includes patient measurements, orders, diagnoses, procedures, treatments, and deidentified free-text clinical notes. MIMIC-IV is intended to support a wide array of research studies and educational material, helping to reduce barriers to conducting clinical research.

Tai Chi training's effect on lower extremity muscle co-contraction during single- and dual-task gait: Cross-sectional and randomized trial studies.

BACKGROUND: Tai Chi (TC) mind-body exercise has been shown to reduce falls and improve balance and gait, however, few studies have evaluated the role of lower extremity muscle activation patterns in the observed benefits of TC on mobility. PURPOSE: To perform an exploratory analysis of the association between TC training and levels of lower extremity muscle co-contraction in healthy adults during walking under single-task (ST) and cognitive dual-task (DT) conditions. METHODS: Surface electromyography of the anterior tibialis and lateral gastrocnemius muscles was recorded during 90 sec trials of overground ST (walking normally) and DT (walking with verbalized serial subtractions) walking. A mean co-contraction index (CCI), across all strides, was calculated based on the percentage of total muscle activity when antagonist muscles were simultaneously activated. A hybrid study design investigated long-term effects of TC via a cross-sectional comparison of 27 TC experts and 60 age-matched TC-naïve older adults. A longitudinal comparison assessed the shorter-term effects of TC; TC-naïve participants were randomly allocated to either 6 months of TC training or to usual care. RESULTS: Across all participants at baseline, greater CCI was correlated with slower gait speed under DT (ß(95% CI) = -26.1(-48.6, -3.7)) but not ST (ß(95% CI) = -15.4(-38.2, 7.4)) walking. Linear models adjusting for age, gender, BMI and other factors that differed at baseline indicated that TC experts exhibited lower CCI compared to TC naives under DT, but not ST conditions (ST: mean difference (95% CI) = -7.1(-15.2, 0.97); DT: mean difference (95% CI) = -10.1(-18.1, -2.4)). No differences were observed in CCI for TC-naive adults randomly assigned to 6 months of TC vs. usual care. CONCLUSION: Lower extremity muscle co-contraction may play a role in the observed benefit of longer-term TC training on gait and postural control. Longer-duration and adequately powered randomized trials are needed to evaluate the effect of TC on neuromuscular coordination and its impact on postural control. TRIAL REGISTRATION: The randomized trial component of this study was registered at ClinicalTrials.gov (NCT01340365).

Complexity-Based Measures of Heart Rate Dynamics in Older Adults Following Long- and Short-Term Tai Chi Training: Cross-sectional and Randomized Trial Studies.

Measures characterizing the complexity of heart rate (HR) dynamics have been informative in predicting age- and disease-related decline in cardiovascular health, but few studies have evaluated whether mind-body exercise can impact HR complexity. This study evaluated the effects of long-term Tai Chi (TC) practice on the complexity of HR dynamics using an observational comparison of TC experts and age- and gender-matched TC-naïve individuals. Shorter-term effects of TC were assessed by randomly assigning TC-naïve participants to either TC group to receive six months of TC training or to a waitlist control group. 23 TC experts (age = 63.3 ± 8.0 y; 24.6 ± 12.0 y TC experience) and 52 TC-naïve (age = 64.3 ± 7.7 y) were enrolled. In cross-sectional analyses, TC experts had a higher overall complexity index (CI, p = 0.004) and higher entropy at multiple individual time scales (p < 0.05); these findings persisted in models accounting for age, gender, body mass index (BMI), and physical activity levels. Longitudinal changes in complexity index did not differ significantly following random assignment to six months of TC vs. a waitlist control; however, within the TC group, complexity at select time scales showed statistically non-significant trends toward increases. Our study supports that longer-term TC mind-body training may be associated with increased complexity of HR dynamics.

Cost-Effectiveness of a Team-Based Integrative Medicine Approach to the Treatment of Back Pain.

OBJECTIVES: To report the results of health economic analyses comparing two treatment approaches for chronic low back pain (CLBP). DESIGN: Observational prospective cohort study comparing effectiveness and cost-effectiveness of CLBP care provided at an integrative care clinic with that provided in other clinics within the same hospital. CLBP-related medical utilization, function, quality of life, and days of work incapacity were self-reported at baseline, 3, 6, and 12 months. SETTINGS/LOCATION: Osher Clinical Center (OCC) based at a tertiary academic hospital (Brigham and Women's Hospital [BWH]) and other clinics at BWH. SUBJECTS: CLBP patients seeking care at OCC or non-OCC BWH clinics. INTERVENTIONS: Integrative or conventional care for CLBP as prescribed by the treating clinician(s). OUTCOME MEASURES: Quality-adjusted life years (QALYs) were estimated per treatment approach based on the SF-12. Cost per QALY gained was evaluated using an incremental cost-effectiveness ratio (ICER). ICERs based on CLBP-specific effectiveness measures (Roland Disability Questionnaire [RDQ] and bothersomeness of pain [BOP]) were exploratory outcomes. RESULTS: Total adjusted annual CLBP-related costs per patient were greater in the OCC versus non-OCC group ($11,526.73 vs. $6,810.63). Between group differences in QALYs were small and ICER estimate of cost per QALY gained was high ($436,676). However, unadjusted mean direct costs per patient decreased over time in the OCC group. Savings in direct costs of $391 (95% confidence interval: -1,078 to 1,861) were observed in the OCC group for the 6- to 12-month period, driven primarily by reduced medication usage. ICERs based on adjusted RDQ and BOP group differences showed cost of $2,073 and $4,203 for a one-point reduction per respective scale. CONCLUSIONS: When adjusted for baseline differences, self-reported costs were higher in the OCC group with only small effects on QALYs. However, trends toward decreased direct expenditures and medication usage over time warrant further investigation. Future studies evaluating potential benefits of integrative care models for the management of CLBP should employ randomized designs, longer observational periods, and explore multiple metrics of cost-effectiveness.

Tai Chi for Reducing Dual-task Gait Variability, a Potential Mediator of Fall Risk in Parkinson's Disease: A Pilot Randomized Controlled Trial.

OBJECTIVES: To assess the feasibility and inform design features of a fully powered randomized controlled trial (RCT) evaluating the effects of Tai Chi (TC) in Parkinson's disease (PD) and to select outcomes most responsive to TC assessed during off-medication states. DESIGN: Two-arm, wait-list controlled RCT. SETTINGS: Tertiary care hospital. SUBJECTS: Thirty-two subjects aged 40-75 diagnosed with idiopathic PD within 10 years. INTERVENTIONS: Six-month TC intervention added to usual care (UC) versus UC alone. OUTCOME MEASURES: Primary outcomes were feasibility-related (recruitment rate, adherence, and compliance). Change in dual-task (DT) gait stride-time variability (STV) from baseline to 6 months was defined, a priori, as the clinical outcome measure of primary interest. Other outcomes included: PD motor symptom progression (Unified Parkinson's Disease Rating Scale [UPDRS]), PD-related quality of life (PDQ-39), executive function (Trail Making Test), balance confidence (Activity-Specific Balance Confidence Scale, ABC), and Timed Up and Go test (TUG). All clinical assessments were made in the off-state for PD medications. RESULTS: Thirty-two subjects were enrolled into 3 sequential cohorts over 417 days at an average rate of 0.08 subjects per day. Seventy-five percent (12/16) in the TC group vs 94% (15/16) in the UC group completed the primary 6-month follow-up assessment. Mean TC exposure hours overall: 52. No AEs occurred during or as a direct result of TC exercise. Statistically nonsignificant improvements were observed in the TC group at 6 months in DT gait STV (TC [20.1%] vs UC [-0.1%] group [effect size 0.49; P = .47]), ABC, TUG, and PDQ-39. UPDRS progression was modest and very similar in TC and UC groups. CONCLUSIONS: Conducting an RCT of TC for PD is feasible, though measures to improve recruitment and adherence rates are needed. DT gait STV is a sensitive and logical outcome for evaluating the combined cognitive-motor effects of TC in PD.

A Multidisciplinary Integrative Medicine Team in the Treatment of Chronic Low-Back Pain: An Observational Comparative Effectiveness Study.

OBJECTIVES: Chronic low-back pain (CLBP) is burdensome and costly, and a common condition for which adults use integrative therapies. The effectiveness of multidisciplinary integrative approaches has not been well studied. The purpose of this observational study was to compare characteristics and outcomes of CLBP patients treated at the Osher Clinical Center (OCC) versus other clinics at Brigham and Women's Hospital. DESIGN: Observational comparative effectiveness study. SETTING: Tertiary care hospital. SUBJECTS: Patients ≥21 years with 3+ months of CLBP or 6+ months of intermittent low-back pain. INTERVENTION: All patients were observed for 12 months. OCC patients received care at the integrative clinic (7.3 visits on average over 13 weeks); non-OCC patients received usual care at other clinics of the same hospital. OUTCOME MEASURES: Primary outcomes: change from baseline to 6 months in functional status (Roland Disability Questionnaire [RDQ]) and bothersomeness of pain (BOP). SECONDARY OUTCOMES: change in RDQ and BOP at 3 and 12 months, percentages of patients with clinically meaningful (≥30%) improvements. RESULTS: One hundred fifty-six OCC and 153 non-OCC participants were enrolled; follow-up was 90.4 and 98.0%, respectively, at 12 months. There were substantial differences in baseline characteristics between groups. For RDQ, the adjusted mean group difference was nonsignificant at 6 months; for BOP, the differences were significant, but clinically small. At 12 months, the observed benefit on RDQ was significant and clinically meaningful; for BOP, there were significant, but clinically small differences. Percentages of patients with ≥30% improvements in RDQ were significantly greater in the OCC group only at 12 months, and both 6 and 12 months for BOP. CONCLUSIONS: Baseline characteristics can differ between those who select different sources of healthcare for CLBP. While benefits seen in the OCC versus non-OCC clinics were not large, further evaluation through randomized trials might be warranted to provide a more definitive evaluation.

Can Tai Chi training impact fractal stride time dynamics, an index of gait health, in older adults? Cross-sectional and randomized trial studies.

PURPOSE: To determine if Tai Chi (TC) has an impact on long-range correlations and fractal-like scaling in gait stride time dynamics, previously shown to be associated with aging, neurodegenerative disease, and fall risk. METHODS: Using Detrended Fluctuation Analysis (DFA), this study evaluated the impact of TC mind-body exercise training on stride time dynamics assessed during 10 minute bouts of overground walking. A hybrid study design investigated long-term effects of TC via a cross-sectional comparison of 27 TC experts (24.5 ± 11.8 yrs experience) and 60 age- and gender matched TC-naïve older adults (50-70 yrs). Shorter-term effects of TC were assessed by randomly allocating TC-naïve participants to either 6 months of TC training or to a waitlist control. The alpha (α) long-range scaling coefficient derived from DFA and gait speed were evaluated as outcomes. RESULTS: Cross-sectional comparisons using confounder adjusted linear models suggest that TC experts exhibited significantly greater long-range scaling of gait stride time dynamics compared with TC-naïve adults. Longitudinal random-slopes with shared baseline models accounting for multiple confounders suggest that the effects of shorter-term TC training on gait dynamics were not statistically significant, but trended in the same direction as longer-term effects although effect sizes were very small. In contrast, gait speed was unaffected in both cross-sectional and longitudinal comparisons. CONCLUSION: These preliminary findings suggest that fractal-like measures of gait health may be sufficiently precise to capture the positive effects of exercise in the form of Tai Chi, thus warranting further investigation. These results motivate larger and longer-duration trials, in both healthy and health-challenged populations, to further evaluate the potential of Tai Chi to restore age-related declines in gait dynamics. TRIAL REGISTRATION: The randomized trial component of this study was registered at ClinicalTrials.gov (NCT01340365).

Impact of Short- and Long-term Tai Chi Mind-Body Exercise Training on Cognitive Function in Healthy Adults: Results From a Hybrid Observational Study and Randomized Trial.

BACKGROUND: Cognitive decline amongst older adults is a significant public health concern. There is growing interest in behavioral interventions, including exercise, for improving cognition. Studies to date suggest tai chi (TC) may be a safe and potentially effective exercise for preserving cognitive function with aging; however, its short-term and potential long-term impact on physically active, healthy adults is unclear. OBJECTIVE: To compare differences in cognitive function among long-term TC expert practitioners and age-matched and gender-matched TC-naïve adults and to determine the effects of short-term TC training on measures of cognitive function in healthy, nonsedentary adults. DESIGN: A hybrid design including an observational comparison and a 2-arm randomized clinical trial (RCT). PARTICIPANTS: Healthy, nonsedentary, TC-naive adults (50 y-79 y) and age-matched and gender-matched long-term TC experts. METHODS: A cross-sectional comparison of cognitive function in healthy TC-naïve (n=60) and TC expert (24.5 y ÷ 12 y experience; n=27) adults: TC-naïve adults then completed a 6-month, 2-arm, wait-list randomized clinical trial of TC training. Six measures of cognitive function were assessed for both cross-sectional and longitudinal comparisons. RESULTS: TC experts exhibited trends towards better scores on all cognitive measures, significantly so for category fluency (P=.01), as well as a composite z score summarizing all 6 cognitive assessments (P=.03). In contrast, random assignment to 6 months of TC training in TC-naïve adults did not significantly improve any measures of cognitive function. CONCLUSIONS: In healthy nonsedentary adults, long-term TC training may help preserve cognitive function; however, the effect of short-term TC training in healthy adults remains unclear. TRIAL REGISTRATION: ClinicalTrials.gov NCT01340365.

Tai Chi Training may Reduce Dual Task Gait Variability, a Potential Mediator of Fall Risk, in Healthy Older Adults: Cross-Sectional and Randomized Trial Studies.

BACKGROUND: Tai Chi (TC) exercise improves balance and reduces falls in older, health-impaired adults. TC's impact on dual task (DT) gait parameters predictive of falls, especially in healthy active older adults, however, is unknown. PURPOSE: To compare differences in usual and DT gait between long-term TC-expert practitioners and age-/gender-matched TC-naïve adults, and to determine the effects of short-term TC training on gait in healthy, non-sedentary older adults. METHODS: A cross-sectional study compared gait in healthy TC-naïve and TC-expert (24.5 ± 12 years experience) older adults. TC-naïve adults then completed a 6-month, two-arm, wait-list randomized clinical trial of TC training. Gait speed and stride time variability (Coefficient of Variation %) were assessed during 90 s trials of undisturbed and cognitive DT (serial subtractions) conditions. RESULTS: During DT, gait speed decreased (p < 0.003) and stride time variability increased (p < 0.004) in all groups. Cross-sectional comparisons indicated that stride time variability was lower in the TC-expert vs. TC-naïve group, significantly so during DT (2.11 vs. 2.55%; p = 0.027); by contrast, gait speed during both undisturbed and DT conditions did not differ between groups. Longitudinal analyses of TC-naïve adults randomized to 6 months of TC training or usual care identified improvement in DT gait speed in both groups. A small improvement in DT stride time variability (effect size = 0.2) was estimated with TC training, but no significant differences between groups were observed. Potentially important improvements after TC training could not be excluded in this small study. CONCLUSION: In healthy active older adults, positive effects of short- and long-term TC were observed only under cognitively challenging DT conditions and only for stride time variability. DT stride time variability offers a potentially sensitive metric for monitoring TC's impact on fall risk with healthy older adults.

Complexity-Based Measures Inform Effects of Tai Chi Training on Standing Postural Control: Cross-Sectional and Randomized Trial Studies.

BACKGROUND: Diminished control of standing balance, traditionally indicated by greater postural sway magnitude and speed, is associated with falls in older adults. Tai Chi (TC) is a multisystem intervention that reduces fall risk, yet its impact on sway measures vary considerably. We hypothesized that TC improves the integrated function of multiple control systems influencing balance, quantifiable by the multi-scale "complexity" of postural sway fluctuations. OBJECTIVES: To evaluate both traditional and complexity-based measures of sway to characterize the short- and potential long-term effects of TC training on postural control and the relationships between sway measures and physical function in healthy older adults. METHODS: A cross-sectional comparison of standing postural sway in healthy TC-naïve and TC-expert (24.5±12 yrs experience) adults. TC-naïve participants then completed a 6-month, two-arm, wait-list randomized clinical trial of TC training. Postural sway was assessed before and after the training during standing on a force-plate with eyes-open (EO) and eyes-closed (EC). Anterior-posterior (AP) and medio-lateral (ML) sway speed, magnitude, and complexity (quantified by multiscale entropy) were calculated. Single-legged standing time and Timed-Up-and-Go tests characterized physical function. RESULTS: At baseline, compared to TC-naïve adults (n = 60, age 64.5±7.5 yrs), TC-experts (n = 27, age 62.8±7.5 yrs) exhibited greater complexity of sway in the AP EC (P = 0.023), ML EO (P<0.001), and ML EC (P<0.001) conditions. Traditional measures of sway speed and magnitude were not significantly lower among TC-experts. Intention-to-treat analyses indicated no significant effects of short-term TC training; however, increases in AP EC and ML EC complexity amongst those randomized to TC were positively correlated with practice hours (P = 0.044, P = 0.018). Long- and short-term TC training were positively associated with physical function. CONCLUSION: Multiscale entropy offers a complementary approach to traditional COP measures for characterizing sway during quiet standing, and may be more sensitive to the effects of TC in healthy adults. TRIAL REGISTRATION: ClinicalTrials.gov NCT01340365.

Applying the Kelvin probe to biological tissues: theoretical and computational analyses.

The Kelvin probe measures surface electrical potential without making physical contact with the specimen. It relies on capacitive coupling between an oscillating metal tip that is normal to a specimen's surface. Kelvin probes have been increasingly used to study surface and electrical properties of metals and semiconductors and are capable of detecting material surface potentials with submillivolt resolution at a micrometer spatial scale. Its capability for measuring electrical potential without being confounded by electrode-specimen contact makes extending its use towards biological materials particularly appealing. However, the theoretical basis for applying the Kelvin probe to dielectric or partially conductive materials such as biological tissue has not been evaluated and remains unclear. This study develops the theoretical basis underlying Kelvin probe measurements in five theoretical materials: highly conductive, conductive dielectric with rapid charge relaxation, conductive dielectric with slow charge relaxation, perfect dielectric, and tissue with a bulk serial resistance. These theoretically derived equations are then computationally analyzed using parameters from both theoretical specimens and actual biomaterials-including wet skin, dry skin, cerebrospinal fluid, and tendon. Based on these analyses, a Kelvin probe performs in two distinct ways depending on the charge relaxation rates of the sample: The specimen is treated either as a perfect dielectric or as highly conductive material. Because of their rapid relaxation rate and increased permittivity biomaterials behave similarly to highly conductive materials, such as metal, when evaluated by the Kelvin probe. These results indicate that the Kelvin probe can be readily applied to studying the surface potential of biological tissue.

Electrical potential of acupuncture points: use of a noncontact scanning Kelvin probe.

Objective. Acupuncture points are reportedly distinguishable by their electrical properties. However, confounders arising from skin-to-electrode contact used in traditional electrodermal methods have contributed to controversies over this claim. The Scanning Kelvin Probe is a state-of-the-art device that measures electrical potential without actually touching the skin and is thus capable of overcoming these confounding effects. In this study, we evaluated the electrical potential profiles of acupoints LI-4 and PC-6 and their adjacent controls. We hypothesize that acupuncture point sites are associated with increased variability in potential compared to adjacent control sites. Methods. Twelve healthy individuals were recruited for this study. Acupuncture points LI-4 and PC-6 and their adjacent controls were assessed. A 2 mm probe tip was placed over the predetermined skin site and adjusted to a tip-to-sample distance of 1.0 mm under tip oscillation settings of 62.4 Hz frequency. A 6 × 6 surface potential scan spanning a 1.0 cm × 1.0 cm area was obtained. Results. At both the PC-6 and LI-4 sites, no significant differences in mean potential were observed compared to their respective controls (Wilcoxon rank-sum test, P = 0.73 and 0.79, resp.). However, the LI-4 site was associated with significant increase in variability compared to its control as denoted by standard deviation and range (P = 0.002 and 0.0005, resp.). At the PC-6 site, no statistical differences in variability were observed. Conclusion. Acupuncture points may be associated with increased variability in electrical potential.