Impact of the Comprehensive Care for Joint Replacement Bundled Payment Model on Postoperative Utilization of Home Health and Outpatient Physical Therapy Services.

OBJECTIVE: To study the effect of the Comprehensive Care for Joint Replacement (CJR) bundled payment program on postoperative home health and outpatient physical therapy (PT) for total hip or knee arthroplasty (THA/TKA). DESIGN: Retrospective cohort with national Medicare data (5% claims) using a difference-in-differences analysis comparing January 2013-September 2015 (before) versus October 2016-September 2019 (after). SETTING: Administrative claims from hospitals in 34 metropolitan statistical areas with mandatory CJR participation as of 2018 and 42 control metropolitan statistical areas. PARTICIPANTS: Episodes in fee-for-service Medicare beneficiaries (5% claims) undergoing elective THA (n=6327) or TKA (n=10,764) with community discharge. INTERVENTIONS: Implementation of CJR bundled payment program. MAIN OUTCOME MEASURES: Home health and outpatient PT, including any use and number of visits. RESULTS: Program implementation was associated with an increased percentage of THA episodes using home health PT (+8.0 percentage-point change; 95% CI, +3.5 to +12.6; P=.001) but a decreased per-episode number of home health PT visits for THA (-1.1; 95% CI, -1.6 to -0.6; P<.001) and TKA (-1.1; 95% CI, -1.4 to -0.7; P<.001). The program was also associated with an increased per-episode number of outpatient PT visits for TKA in the primary but not sensitivity analyses (+0.8; 95% CI, +0.1 to +1.4; P=.02). CONCLUSIONS: Findings of increased home health PT may reflect an intentional shift in care from the inpatient postacute setting to the community to decrease costs. Alternatively, the limited effect of CJR, particularly on outpatient PT, could reflect challenges with care coordination in a retrospective bundle spanning multiple care settings.

Low voltage-activated calcium channels gate transmitter release at the dorsal root ganglion sandwich synapse.

A subpopulation of dorsal root ganglion (DRG) neurons are intimately attached in pairs and separated solely by thin satellite glial cell membrane septa. Stimulation of one neuron leads to transglial activation of its pair by a bi-, purinergic/glutamatergic synaptic pathway, a transmission mechanism that we term sandwich synapse (SS) transmission. Release of ATP from the stimulated neuron can be attributed to a classical mechanism involving Ca(2+) entry via voltage-gated calcium channels (CaV) but via an unknown channel type. Specific blockers and toxins ruled out CaV1, 2.1 and 2.2. Transmission was, however, blocked by a moderate depolarization (-50 mV) or low-concentration Ni(2+) (0.1 mM). Transmission persisted using a voltage pulse to -40 mV from a holding potential of -80 mV, confirming the involvement of a low voltage-activated channel type and limiting the candidate channel type to either CaV3.2 or a subpopulation of inactivation- and Ni(2+)-sensitive CaV2.3 channels. Resistance of the neuron calcium current and SS transmission to SNX482 argue against the latter. Hence, we conclude that inter-somatic transmission at the DRG SS is gated by CaV3.2 type calcium channels. The use of CaV3 family channels to gate transmission has important implications for the biological function of the DRG SS as information transfer would be predicted to occur not only in response to action potentials but also to sub-threshold membrane voltage oscillations. Thus, the SS synapse may serve as a homeostatic signalling mechanism between select neurons in the DRG and could play a role in abnormal sensation such as neuropathic pain.

Transglial transmission at the dorsal root ganglion sandwich synapse: glial cell to postsynaptic neuron communication.

The dorsal root ganglion (DRG) contains a subset of closely-apposed neuronal somata (NS) separated solely by a thin satellite glial cell (SGC) membrane septum to form an NS-glial cell-NS trimer. We recently reported that stimulation of one NS with an impulse train triggers a delayed, noisy and long-lasting response in its NS pair via a transglial signaling pathway that we term a 'sandwich synapse' (SS). Transmission could be unidirectional or bidirectional and facilitated in response to a second stimulus train. We have shown that in chick or rat SS the NS-to-SGC leg of the two-synapse pathway is purinergic via P2Y2 receptors but the second SGC-to-NS synapse mechanism remained unknown. A noisy evoked current in the target neuron, a reversal potential close to 0 mV, and insensitivity to calcium scavengers or G protein block favored an ionotropic postsynaptic receptor. Selective block by D-2-amino-5-phosphonopentanoate (AP5) implicated glutamatergic transmission via N-methyl-d-aspartate receptors. This agent also blocked NS responses evoked by puff of UTP, a P2Y2 agonist, directly onto the SGC cell, confirming its action at the second synapse of the SS transmission pathway. The N-methyl-d-aspartate receptor NR2B subunit was implicated by block of transmission with ifenprodil and by its immunocytochemical localization to the NS membrane, abutting the glial septum P2Y2 receptor. Isolated DRG cell clusters exhibited daisy-chain and branching NS-glial cell-NS contacts, suggestive of a network organization within the ganglion. The identification of the glial-to-neuron transmitter and receptor combination provides further support for transglial transmission and completes the DRG SS molecular transmission pathway.

Purinergic transmission and transglial signaling between neuron somata in the dorsal root ganglion.

Most dorsal root ganglion neuronal somata (NS) are isolated from their neighbours by a satellite glial cell (SGC) sheath. However, some NS are associated in pairs, separated solely by the membrane septum of a common SGC to form a neuron-glial cell-neuron (NGlN) trimer. We reported that stimulation of one NS evokes a delayed, noisy and long-duration inward current in both itself and its passive partner that was blocked by suramin, a general purinergic antagonist. Here we test the hypothesis that NGlN transmission involves purinergic activation of the SGC. Stimulation of the NS triggered a sustained current noise in the SGC. Block of transmission through the NGlN by reactive blue 2 or thapsigargin, a Ca(2+) store-depletion agent, implicated a Ca(2+) store discharge-linked P2Y receptor. P2Y2 was identified by simulation of the NGlN-like transmission by puffing UTP onto the SGC and by immunocytochemical localization to the SGC membrane septum. Block of the UTP effect by BAPTA, an intracellular Ca(2+) scavenger, supported the involvement of SGC Ca(2+) stores in the signaling pathway. We infer that transmission through the NGlN trimer involves secretion of ATP from the NS and triggering of SGC Ca(2+) store discharge via P2Y2 receptors. Presumably, cytoplasmic Ca(2+) elevation leads to the release of an as-yet unidentified second transmitter from the glial cell to complete transmission. Thus, the two NS of the NGlN trimer communicate via a 'sandwich synapse' transglial pathway, a novel signaling mechanism that may contribute to information transfer in other regions of the nervous system.

Spatiotemporal parameters from remote smartphone-based gait analysis are associated with lower extremity functional scale categories.

Objective: Self-report tools are recommended in research and clinical practice to capture individual perceptions regarding health status; however, only modest correlations are found with performance-based results. The Lower Extremity Functional Scale (LEFS) is one well-validated measure of impairment affecting physical activities that has been compared with objective tests. More recently, mobile gait assessment software can provide comprehensive motion tracking output from ecologically valid environments, but how this data relates to subjective scales is unknown. Therefore, the association between the LEFS and walking variables remotely collected by a smartphone was explored. Methods: Proprietary algorithms extracted spatiotemporal parameters detected by a standard integrated inertial measurement unit from 132 subjects enrolled in physical therapy for orthopedic or neurological rehabilitation. Users initiated ambulation recordings and completed questionnaires through the OneStep digital platform. Discrete categories were created based on LEFS score cut-offs and Analysis of Variance was applied to estimate the difference in gait metrics across functional groups (Low-Medium-High). Results: The main finding of this cross-sectional retrospective study is that remotely-collected biomechanical walking data are significantly associated with individuals' self-evaluated function as defined by LEFS categorization (n = 132) and many variables differ between groups. Velocity was found to have the strongest effect size. Discussion: When patients are classified according to subjective mobility level, there are significant differences in quantitative measures of ambulation analyzed with smartphone-based technology. Capturing real-time information about movement is important to obtain accurate impressions of how individuals perform in daily life while understanding the relationship between enacted activity and relevant clinical outcomes.

Retrospective case-control study to compare exoskeleton-assisted walking with standard care in subacute non-traumatic brain injury patients.

BACKGROUND: Advanced technologies are increasingly used to address impaired mobility after neurological insults, with growing evidence of their benefits for various populations. However, certain robotic devices have not been extensively investigated in specific conditions, limiting knowledge about optimal application for healthcare. OBJECTIVE: To compare effectiveness of conventional gait training with exoskeleton-assisted walking for non-traumatic brain injury during early stage rehabilitation. METHODS: Clinical evaluation data at admission and discharge were obtained in a retrospective case-control design. Patients received standard of care physical therapy either using Ekso GT or not. Within- or between-group statistical tests were performed to determine change over time and interventional differences. RESULTS: This study analyzed forty-nine individuals (33% female), 20 controls and 29 Ekso participants who were equivalent at baseline. Both groups improved in Functional Independence Measure scores and ambulation ability (p < .00001 and p < .001, respectively). Control subjects demonstrated significantly different distance walked and assistance level values at discharge from those who were treated with the exoskeleton (p < .01). CONCLUSION: Robotic locomotion is non-inferior for subacute functional recovery after non-traumatic brain injury. Conventional therapy produced larger gait performance gains during hospitalization. Further research is needed to understand specific factors influencing efficacy and the long-term implications after rehabilitation.

Slow chemical transmission between dorsal root ganglion neuron somata.

Somatic sensory neuron somata are located within the dorsal root ganglia (DRG) and are mostly ensheathed by individual satellite glial cell sheets. It has been noted, however, that a subpopulation of these DRG somata are intimately associated, separated only by a single thin satellite glial cell membrane septum. We set out to test whether such neuron-glial cell-neuron trimers (NGlNs) are also linked functionally. The presence of NGlNs in chick DRGs was confirmed by electron microscopy. Selective satellite glial cell immunostains were identified and were used to image the inter-neuron septa in DRG frozen sections. We used a gentle, dispase-based enzymatic method to isolate chick and rat NGlNs in vitro for double patch clamp recordings. In the majority of pairs tested, an action potential-like stimulus train delivered to one soma resulted in a delayed, noisy and long-duration response in its idle partner. The response to a second stimulus train given minutes later was markedly facilitated. Both bidirectional and unidirectional transmission was observed between the paired neurons. Transmission was chemical and block by the general purinergic blocker suramin implicated ATP as a neurotransmitter. We conclude that the two neuronal somata in the NGlN can communicate by chemical transmission, which may involve a transglial, bi-synaptic pathway. This novel soma-to-soma transmission reflects a novel form of processing that may play a role in sensory disorders in the DRG and interneuron communication in the central nervous system.

Recording context matters: Differences in gait parameters collected by the OneStep smartphone application.

BACKGROUND: Detailed understanding of impairments that underlie walking dysfunction through objective measures is essential to diagnosis, evaluation and care planning. Despite significant developments in motion tracking technologies, there is a dearth of research about the influence of remote monitoring context on performance. The objective of this study was to determine whether gait parameters collected by the OneStep smartphone application differ based on the recording condition. METHODS: Retrospective repeated measures univariate analysis was performed on data extracted based on detected activity, either spontaneous (background recording) or consciously initiated (in app) walks, of 25 patients enrolled in a physical therapy program. FINDINGS: Across 7227 walking bouts, significant differences between the two paradigms in velocity (g = 0.48), double support (g = 0.37), stride length (g = 0.37) and step length of the affected side (g = 0.32) were revealed. Overall, the passively recorded walks presented a less clinically favorable spatiotemporal pattern for each of these variables. INTERPRETATION: The recording context of walks that were used for analysis appears to significantly affect the biomechanical output of the OneStep application. It is unclear whether the disparity found would impact functional recovery of individuals undergoing rehabilitation due to neurological or musculoskeletal disorder. Clinicians may consider this information when incorporating remotely-acquired quantitative gait analysis and interpreting care outcomes as part of therapeutic practice. Future work can further investigate the behavioral and environmental factors contributing to how movement occurs in specific clinical populations when monitored via mobile health systems.

Exergaming delivery of a balance and fall prevention program for older adults: A feasibility study.

Objective: Older adults are at high risk of falls and this problem calls for efficient and scalable interventions. This study investigated whether a motion capture system paired with balance training exergaming software is a feasible strategy to deliver therapeutic exercise to older adults in an aged care facility. Methods: This study analyzed data from a quality improvement rehabilitation initiative. Two convenience samples of older adults were included: a usual care group (n = 12), admitted to a rehabilitation hospital and receiving standard in-patient therapy 5×/week and the Evolv group (n = 12), admitted to an aged care facility, prescribed exergaming 3×/week. All participants performed 30-minute exercise sessions based on a fall prevention program over 3 months. The Short Physical Performance Battery (SPPB) and Tinetti Performance Oriented Mobility Assessment test were administered pre- and post-treatment. Results: No adverse events were recorded during the interventions. Mean SPPB increase for Evolv participants was 2.25 ± 1.35 (p < .001, CI for mean = 1.39 to 3.11, d = 1.66), compared with a non-significant change in the usual care group (mean increase = 2.25 ± 3.82, p = .066, CI for mean = -0.18 to 4.68, d = 0.59). Tinetti improvement was significant for the individuals receiving usual care (3.83 ± 2.82, p = .012, CI for mean = 1.01 to 6.66, d = 0.86) but there were no significant between-group differences in outcomes. Conclusions: Exergaming with the Evolv system for balance and strength training may be a feasible strategy to improve physical function for older adults recovering in an aged care facility.

Post-acute COVID-19 Syndrome Negatively Impacts Physical Function, Cognitive Function, Health-Related Quality of Life, and Participation.

OBJECTIVE: This report describes persistent symptoms associated with post-acute COVID-19 syndrome (PACS) and the impact of these symptoms on physical function, cognitive function, health-related quality of life, and participation. DESIGN: This study used a cross-sectional observational study design. Patients attending Mount Sinai's post-acute COVID-19 syndrome clinic completed surveys containing patient-reported outcomes. RESULTS: A total of 156 patients completed the survey, at a median (range) time of 351 days (82-457 days) after COVID-19 infection. All patients were prevaccination. The most common persistent symptoms reported were fatigue (n = 128, 82%), brain fog (n = 105, 67%), and headache (n = 94, 60%). The most common triggers of symptom exacerbation were physical exertion (n = 134, 86%), stress (n = 107, 69%), and dehydration (n = 77, 49%). Increased levels of fatigue (Fatigue Severity Scale) and dyspnea (Medical Research Council) were reported, alongside reductions in levels of regularly completed physical activity. Ninety-eight patients (63%) scored for at least mild cognitive impairment (Neuro-Qol), and the domain of the EuroQol: 5 dimension, 5 level most impacted was Self-care, Anxiety/Depression and Usual Activities. CONCLUSIONS: Persistent symptoms associated with post-acute COVID-19 syndrome seem to impact physical and cognitive function, health-related quality of life, and participation in society. More research is needed to further clarify the relationship between COVID-19 infection and post-acute COVID-19 syndrome symptoms, the underlying mechanisms, and treatment options.

Publication Rate and Consistency of Registered Trials of Motor-Based Stroke Rehabilitation.

OBJECTIVE: To determine the publication rate of motor-rehabilitation trials poststroke and the consistency between registry records and their corresponding main publications in trial design, primary objectives and outcomes, eligibility criteria, and sample size. METHODS: We searched 18 clinical trial registries to identify randomized controlled trials of motor-based stroke rehabilitation registered after July 2005 and completed before April 2017. Eligible trials included adults with stroke, with at least one outcome measure related to motor function. Information in the registry records was compared with that of their main publications, if any. RESULTS: Three hundred twenty-three trials met our eligibility criteria; we were unable to find a peer-reviewed publication reporting the main findings for 46% (150/323) of these. Of the 169 trials with peer-reviewed articles published in English, 141 (83%) were consistent with the registry record in trial design, 100 (59%) were consistent in primary objectives, 71 (42%) were consistent in primary outcomes, 28 (17%) were consistent in eligibility criteria, and 74 (44%) were consistent in sample size. CONCLUSIONS: Approximately half of motor-based stroke rehabilitation trials were not published, even more than 3 years after the end of the trial. When main publications were found, they substantially deviated from information in the registry record. These findings highlight the importance of trial registries for identifying unpublished stroke rehabilitation trials and of searching trial registries when conducting systematic reviews and meta-analysis to help ensure that reviews are unbiased.

Longitudinal change in spatiotemporal gait symmetry after discharge from inpatient stroke rehabilitation.

Purpose: To describe the change in spatiotemporal gait asymmetry after discharge from stroke rehabilitation and examine the relationship with change in other clinical outcome measures.Methods: Secondary analysis of a prospective cohort study was conducted. Swing time and step length symmetry, balance, mobility, gait speed, and motor impairment were assessed at discharge and 6 months later. Participants (n = 61) were classified by shift in symmetry status (Asymmetric-to-Symmetric, Symmetric-to-Asymmetric, No Shift) and magnitude of difference scores (Improved, Worse, No Difference). Correlations between change in spatiotemporal symmetry and the other clinical measures of physical status were calculated.Results: At discharge, 61% (37/61) and 36% (22/61) of participants were asymmetric in swing time and step length, respectively. Of this subgroup, 43% (16/37) and 50% (11/22) shifted to symmetric gait by follow-up. In contrast, only six individuals significantly improved in swing and/or step symmetry according to minimal detectable change. Change in spatiotemporal symmetry was not significantly correlated with change in the clinical outcome measures.Conclusions: Despite overall gains in physical function and decreased prevalence of asymmetry, most individuals with stroke do not improve in swing or step symmetry following discharge from rehabilitation. Further research is necessary to elucidate factors that affect recovery of gait quality.Implications for rehabilitationAsymmetric gait after stroke is a major concern for patients and their therapists but can be resistant to intervention.Spatiotemporal asymmetry persists for many individuals following discharge from hospital stay despite improvement in other gait-related measures.While the determinants of change remain unclear, gait quality should be specifically monitored and addressed to avoid long-term negative effects.

Lower limb muscle activity underlying temporal gait asymmetry post-stroke.

OBJECTIVE: Asymmetric walking after stroke is common, detrimental, and difficult to treat, but current knowledge of underlying physiological mechanisms is limited. This study investigated electromyographic (EMG) features of temporal gait asymmetry (TGA). METHODS: Participants post-stroke with or without TGA and control adults (n = 27, 8, and 9, respectively) performed self-paced overground gait trials. EMG, force plate, and motion capture data were collected. Lower limb muscle activity was compared across groups and sides (more/less affected). RESULTS: Significant group by side interaction effects were found: more affected plantarflexor stance activity ended early (p = .0006) and less affected dorsiflexor on/off time was delayed (p < .01) in persons with asymmetry compared to symmetric and normative controls. The TGA group exhibited fewer dorsiflexor bursts during swing (p = .0009). CONCLUSIONS: Temporal patterns of muscular activation, particularly about the ankle around the stance-to-swing transition period, are associated with TGA. The results may reflect specific impairments or compensations that affect locomotor coordination. SIGNIFICANCE: Neuromuscular underpinnings of spatiotemporal asymmetry have not been previously characterized. These novel findings may inform targeted therapeutic strategies to improve gait quality after stroke.

Consumer Wearable Devices for Activity Monitoring Among Individuals After a Stroke: A Prospective Comparison.

BACKGROUND: Activity monitoring is necessary to investigate sedentary behavior after a stroke. Consumer wearable devices are an attractive alternative to research-grade technology, but measurement properties have not been established. OBJECTIVE: The purpose of this study was to determine the accuracy of 2 wrist-worn fitness trackers: Fitbit Charge HR (FBT) and Garmin Vivosmart (GAR). METHODS: Adults attending in- or outpatient therapy for stroke (n=37) wore FBT and GAR each on 2 separate days, in addition to an X6 accelerometer and Actigraph chest strap monitor. Step counts and heart rate data were extracted, and the agreement between devices was determined using Pearson or Spearman correlation and paired t or Wilcoxon signed rank tests (one- and two-sided). Subgroup analyses were conducted. RESULTS: Step counts from FBT and GAR positively correlated with the X6 accelerometer (ρ=.78 and ρ=.65, P<.001, respectively) but were significantly lower (P<.01). For individuals using a rollator, there was no significant correlation between step counts from the X6 accelerometer and either FBT (ρ=.42, P=.12) or GAR (ρ=.30, P=.27). Heart rate from Actigraph, FBT, and GAR demonstrated responsiveness to changes in activity. Both FBT and GAR positively correlated with Actigraph for average heart rate (r=.53 and .75, P<.01, respectively) and time in target zone (ρ=.49 and .74, P<.01, respectively); these measures were not significantly different, but nonequivalence was found. CONCLUSIONS: FBT and GAR had moderate to strong correlation with best available reference measures of walking activity in individuals with subacute stroke. Accuracy appears to be lower among rollator users and varies according to heart rhythm. Consumer wearables may be a viable option for large-scale studies of physical activity.

Acute electrical stimulation of the subfornical organ induces feeding in satiated rats.

The SFO, a circumventricular organ (CVO) that lacks the normal blood-brain barrier, is an important site in central autonomic regulation. A role for the SFO in sensing circulating satiety signals has been suggested by electrophysiological studies demonstrating that the anorexigenic satiety signals, leptin and amylin, as well as the orexigenic satiety signal, ghrelin, influence the excitability of separate populations of SFO neurons. The present study examined whether acute, short duration, electrical stimulation of the SFO influenced feeding in satiated rats. Electrical stimulation (200 microA) of satiated animals with subfornical organ (SFO) electrode placement (n=6) elicited feeding in all animals tested with a mean latency to eat of 8.0+/-4.0 min after termination of SFO stimulation (mean food consumption: 0.6+/-0.12 g/100g bw). These same rats undergoing a sham stimulation did not eat (mean food consumption: 0.0+/-0.0 g, n=6) nor did animals receiving stimulation with non-SFO electrode placements (mean food consumption: 0.0+/-0.0 g, n=6). SFO stimulation at this intensity elicited drinking in 5/6 animals with a mean latency to drink of 15.2+/-2.6 min. Feeding effects were specific to higher stimulation intensities as lower intensity stimulation (100 microA, n=6) elicited drinking (mean latency to drink: 6.2+/-2.6 min) but did not cause any animal to eat. The results of the present study show that acute, short duration, SFO stimulation induces feeding in satiated rats, lending support for a role for the SFO as an integrator of circulating peptides that control feeding.