Active robotic training improves locomotor function in a stroke survivor

Abstract Background Clinical outcomes after robotic training are often not superior to conventional therapy. One key factor responsible for this is the use of control strategies that provide substantial guidance. This strategy not only leads to a reduction in volitional physical effort, but also interferes with motor relearning. Methods We tested the feasibility of a novel training approach (active robotic training) using a powered gait orthosis (Lokomat) in mitigating post-stroke gait impairments of a 52-year-old male stroke survivor. This gait training paradigm combined patient-cooperative robot-aided walking with a target-tracking task. The training lasted for 4-weeks (12 visits, 3 × per week). The subject’s neuromotor performance and recovery were evaluated using biomechanical, neuromuscular and clinical measures recorded at various time-points (pre-training, post-training, and 6-weeks after training). Results Active robotic training resulted in considerable increase in target-tracking accuracy and reduction in the kinematic variability of ankle trajectory during robot-aided treadmill walking. These improvements also transferred to overground walking as characterized by larger propulsive forces and more symmetric ground reaction forces (GRFs). Training also resulted in improvements in muscle coordination, which resembled patterns observed in healthy controls. These changes were accompanied by a reduction in motor cortical excitability (MCE) of the vastus medialis, medial hamstrings, and gluteus medius muscles during treadmill walking. Importantly, active robotic training resulted in substantial improvements in several standard clinical and functional parameters. These improvements persisted during the follow-up evaluation at 6 weeks. Conclusions The results indicate that active robotic training appears to be a promising way of facilitating gait and physical function in moderately impaired stroke survivors.http://deepblue.lib.umich.edu/bitstream/2027.42/112853/1/12984_2011_Article_375.pd

Recurrence quantification analysis of surface electromyogram supports alterations in motor unit recruitment strategies by anodal transcranial direct current stimulation

International audiencePURPOSE:Recent evidence indicates that anodal transcranial direct current stimulation (tDCS) can selectively alter the EMG/force relationship of agonist arm muscles; however, the mechanisms mediating those changes are less clear. The purpose of this study was to evaluate the effect of anodal tDCS on motor unit synchronization by using a sophisticated non-linear EMG analysis called recurrence quantification analysis (RQA).METHODS:Surface EMG signals were collected from the biceps brachii muscle of eighteen healthy young adults (9 tDCS and 9 control) at various force levels (12.5%, 25%, 37.5%, and 50% maximum) before and after the application of anodal tDCS over the primary motor cortex. RQA was employed to quantify the changes in percentage of determinism (%DET) and laminarity (%LAM) of the surface EMG signals, which are surrogate measures of motor unit synchronization.RESULTS:RQA analyses indicated that the changes in %DET and %LAM scores were significantly higher in the tDCS group than in the control group (p < 0.05) and this effect was particularly pronounced at higher force levels.CONCLUSION:The results of this study provide novel evidence supporting that anodal tDCS significantly alters motor unit firing strategies (i.e., the degree of synchronization) of the biceps brachii muscle

Utility of Pentraxin-3 as a biomarker for diagnosis of acute appendicitis : a systematic review and meta-analysis

Purpose To systematically summarize all relevant data and to define the current evidence on the utility of Pentraxin-3 (PTX3) as a biomarker for acute appendicitis (AA) in children. Methods This review was conducted in accordance with the PRISMA guidelines. PubMed, Embase, Scopus, and Web of Science databases were systematically searched for studies comparing the levels of PTX3 in patients with AA vs healthy controls or non-specific abdominal pain (NSAP). Mean differences were calculated for all outcomes and the inverse variance method was used for weighted mean difference. The methodological quality of the included studies was assessed using the Downs and Black scale. Results Five comparative studies were included. Significantly elevated levels of PTX3 in cases with AA vs healthy controls (WMD: 9.56, 95% CI 7.24-11.88, p < 0.00001), and patients with AA vs NSAP (WMD: 8.05, 95% CI 6.81-9.29, p < 0.00001) were demonstrated. Similarly, in separate meta-analyses, the levels of PTX3 were significantly elevated in children with AA vs healthy controls (WMD: 11.18, 95% CI 10.03-12.34, p < 0.00001), and children with AA vs NSAP (WMD: 8.35, 95% CI 6.88-9.82, p < 0.00001). Conclusions PTX3-levels are elevated in AA, but differentiation between perforated and non-perforated appendicitis demands other methods.Peer reviewe

Utility of Pentraxin-3 as a biomarker for diagnosis of acute appendicitis: a systematic review and meta-analysis

Purpose: To systematically summarize all relevant data and to define the current evidence on the utility of Pentraxin-3 (PTX3) as a biomarker for acute appendicitis (AA) in children. Methods: This review was conducted in accordance with the PRISMA guidelines. PubMed, Embase, Scopus, and Web of Science databases were systematically searched for studies comparing the levels of PTX3 in patients with AA vs healthy controls or non-specific abdominal pain (NSAP). Mean differences were calculated for all outcomes and the inverse variance method was used for weighted mean difference. The methodological quality of the included studies was assessed using the Downs and Black scale. Results: Five comparative studies were included. Significantly elevated levels of PTX3 in cases with AA vs healthy controls (WMD: 9.56, 95% CI 7.24-11.88, p Conclusions: PTX3-levels are elevated in AA, but differentiation between perforated and non-perforated appendicitis demands other methods.</p

Phospholipase D1 Attenuation Therapeutics Promotes Resilience against Synaptotoxicity in 12-Month-Old 3xTg-AD Mouse Model of Progressive Neurodegeneration

Abrogating synaptotoxicity in age-related neurodegenerative disorders is an extremely promising area of research with significant neurotherapeutic implications in tauopathies including Alzheimer’s disease (AD). Our studies using human clinical samples and mouse models demonstrated that aberrantly elevated phospholipase D1 (PLD1) is associated with amyloid beta (Aβ) and tau-driven synaptic dysfunction and underlying memory deficits. While knocking out the lipolytic PLD1 gene is not detrimental to survival across species, elevated expression is implicated in cancer, cardiovascular conditions and neuropathologies, leading to the successful development of well-tolerated mammalian PLD isoform-specific small molecule inhibitors. Here, we address the importance of PLD1 attenuation, achieved using repeated 1 mg/kg of VU0155069 (VU01) intraperitoneally every alternate day for a month in 3xTg-AD mice beginning only from ~11 months of age (with greater influence of tau-driven insults) compared to age-matched vehicle (0.9% saline)-injected siblings. A multimodal approach involving behavior, electrophysiology and biochemistry corroborate the impact of this pre-clinical therapeutic intervention. VU01 proved efficacious in preventing in later stage AD-like cognitive decline affecting perirhinal cortex-, hippocampal- and amygdala-dependent behaviors. Glutamate-dependent HFS-LTP and LFS-LTD improved. Dendritic spine morphology showed the preservation of mushroom and filamentous spine characteristics. Differential PLD1 immunofluorescence and co-localization with Aβ were noted

A pilot study on the feasibility of robot-aided leg motor training to facilitate active participation.

Robot-aided gait therapy offers a promising approach towards improving gait function in individuals with neurological disorders such as stroke or spinal cord injury. However, incorporation of appropriate control strategies is essential for actively engaging the patient in the therapeutic process. Although several control algorithms (such as assist-as-needed and error augmentation) have been proposed to improve active patient participation, we hypothesize that the therapeutic benefits of these control algorithms can be greatly enhanced if combined with a motor learning task to facilitate neural reorganization and motor recovery. Here, we describe an active robotic training approach (patient-cooperative robotic gait training combined with a motor learning task) using the Lokomat and pilot-tested whether this approach can enhance active patient participation during training. Six neurologically intact adults and three chronic stroke survivors participated in this pilot feasibility study. Participants walked in a Lokomat while simultaneously performing a foot target-tracking task that necessitated greater hip and knee flexion during the swing phase of the gait. We computed the changes in tracking error as a measure of motor performance and changes in muscle activation as a measure of active subject participation. Repeated practice of the motor-learning task resulted in significant reductions in target-tracking error in all subjects. Muscle activation was also significantly higher during active robotic training compared to simply walking in the robot. The data from stroke participants also showed a trend similar to neurologically intact participants. These findings provide a proof-of-concept demonstration that combining robotic gait training with a motor learning task enhances active participation