Feasibility and Validation of a Robotic-Based Multisensory Integration Assessment in Healthy Controls and a Stroke Patient.

After experiencing brain damage, stroke patients commonly suffer from motor and sensory impairments that impact their ability to perform volitional movements. Visuo-proprioceptive integration is a critical component of voluntary movement, allowing for accurate movements and a sense of ownership over one's body. While recent studies have increased our understanding of the balance between visual compensation and proprioceptive deficits in stroke patients, quantitative methods for studying multisensory integration are still lacking. This study aimed to evaluate the feasibility of adapting a 3D visuo-proprioceptive disparity (VPD) task into a 2D setting using an upper-limb robotic platform for moderate to severe chronic stroke patients. To assess the implementation of the 2D task, a cohort of unimpaired healthy participants performed the VPD task in both a 3D and 2D environment. We used a computational Bayesian model to predict errors in visuo-proprioceptive integration and compared the model's predictions to real behavioral data. Our findings indicated that the behavioral trends observed in the 2D and 3D tasks were similar, and the model accurately predicted behavior. We then evaluated the feasibility of our task to assess post-stroke deficits in a patient with severe motor and sensory deficits. Ultimately, this work may help to improve our understanding of the significance of visuo-proprioceptive integration and aid in the development of better rehabilitation therapies for improving sensorimotor outcomes in stroke patients.

Epidural stimulation of the cervical spinal cord for post-stroke upper-limb paresis.

Cerebral strokes can disrupt descending commands from motor cortical areas to the spinal cord, which can result in permanent motor deficits of the arm and hand. However, below the lesion, the spinal circuits that control movement remain intact and could be targeted by neurotechnologies to restore movement. Here we report results from two participants in a first-in-human study using electrical stimulation of cervical spinal circuits to facilitate arm and hand motor control in chronic post-stroke hemiparesis ( NCT04512690 ). Participants were implanted for 29 d with two linear leads in the dorsolateral epidural space targeting spinal roots C3 to T1 to increase excitation of arm and hand motoneurons. We found that continuous stimulation through selected contacts improved strength (for example, grip force +40% SCS01; +108% SCS02), kinematics (for example, +30% to +40% speed) and functional movements, thereby enabling participants to perform movements that they could not perform without spinal cord stimulation. Both participants retained some of these improvements even without stimulation and no serious adverse events were reported. While we cannot conclusively evaluate safety and efficacy from two participants, our data provide promising, albeit preliminary, evidence that spinal cord stimulation could be an assistive as well as a restorative approach for upper-limb recovery after stroke.

Poststroke arm and hand paresis: should we target the cervical spinal cord?

Despite advances in understanding of corticospinal motor control and stroke pathophysiology, current rehabilitation therapies for poststroke upper limb paresis have limited efficacy at the level of impairment. To address this problem, we make the conceptual case for a new treatment approach. We first summarize current understanding of motor control deficits in the arm and hand after stroke and their shared physiological mechanisms with spinal cord injury (SCI). We then review studies of spinal cord stimulation (SCS) for recovery of locomotion after SCI, which provide convincing evidence for enhancement of residual corticospinal function. By extrapolation, we argue for using cervical SCS to restore upper limb motor control after stroke.

Performance predictors of motor imagery brain-computer interface based on spatial abilities for upper limb rehabilitation.

Motor Imagery based BCIs (MI-BCIs) allow the control of devices and communication by imagining different mental tasks. Despite many years of research, BCIs are still not the most accurate systems to control applications, due to two main factors: signal processing with classification, and users. It is admitted that BCI control involves certain characteristics and abilities in its users for optimal results. In this study, spatial abilities are evaluated in relation to MI-BCI control regarding flexion and extension mental tasks. Results show considerable correlation (r=0.49) between block design test (visual motor execution and spatial visualization) and extension-rest tasks. Additionally, rotation test (mental rotation task) presents significant correlation (r=0.56) to flexion-rest tasks.

Profiling of alkaloids and eremophilanes in miracle tea (Packera candidissima and P. bellidifolia) products.

Commercial preparations of the Mexican herbal drug known as "miracle tea" (Packera candidissima and P. bellidifolia) have been profiled qualitatively by HPLC and GC-MS. Eremophilanes (3-7) were the major components found in the hexane-soluble fraction, while pyrrolizidine alkaloids (PAs) were identified in the alkaloid extracts. The content of free PAs and their N-oxides was determined for a total of 22 samples, and the results showed that the amount of these hepatotoxic compounds (0.0005-0.94% free PAs; 0.0004-0.55% N-oxides), through the presence of retrorsine (1) and senesionine (2) as the main constituents, may reach toxic levels. Hexane-soluble extracts from commercial presentations (dried whole plants) of both species afforded neoadenostylone (3), 6-(2-methylbutanoyloxy)-9-oxo-1-(10)-furanoeremophilene (4), and epineoadenostylone (5), in addition to methyl-4-hydroxyphenylacetate (8) and methyl-2-(1-hydroxy-4-oxocyclohexyl)acetate (9). Also, epicacalone (6) and the new compound 2ß-hydroxyneoadenostylone (7) were isolated from P. bellidifolia.

Trabajo preliminar sobre evaluación de organizaciones encargadas de la formación de asesores empresariales en Bolivia

Contiene: 1. Introducción. 2. Objetivos. 3. Planteamiento del estudio. 4. Análisis: identificación de instituciones y actividades principales, zonificación significativa para el análisis, educación formal. 5. Conclusiones finales.