Effects of repetitive transcranial magnetic stimulation combined with transcranial direct current stimulation on motor function and cortex excitability in subacute stroke patients: A randomized controlled trial

Objective: To explore effects of repetitive transcranial magnetic stimulation (rTMS) combined with transcranial direct current stimulation (tDCS) on motor function and cortex excitability in subacute stroke patients. Design: Randomized controlled trial. Setting: Inpatient hospitals. Subjects: Sixty-five participants were randomly assigned to four groups: sham, 1Hz rTMS, cathodic tDCS combined with 1Hz rTMS (tDCS-/rTMS-) and anodic tDCS combined with 1Hz rTMS (tDCS+/rTMS-). Interventions: Four interventions were used, including sham, 1Hz rTMS, and cathodal or anodal tDCS, followed by 1Hz rTMS over contralesional motor cortex, which continued for four weeks. Main measures: Outcome measures were motor function and cortical excitability, evaluated by Fugl-Meyer Assessment, National Institutes of Health Stroke Scale and Barthel Index, resting Motion Threshold, Motor Evoked Potentials and Central Motor Conduction Time, assessed at baseline, four weeks and eight weeks. Results: At four weeks after interventions, Fugl-Meyer Assessment lower limb change score in tDCS+/rTMS- group was significantly larger than other three groups ( P < 0.001). There were significant differences in bilateral Motor Evoked Potentials changes between tDCS+/rTMS- group and sham group ( P < 0.05). At eight weeks, compared to other groups, National Institutes of Health Stroke Scale ( P = 0.003), Barthel Index ( P = 0.002), FMA lower limb score ( P < 0.001), and bilateral resting Motion Threshold, Motor Evoked Potentials ( P < 0.05) showed significant changes in tDCS+/rTMS- group. Furthermore, Fugl-Meyer Assessment lower limb change score was associated with increased ipsilesional Motor Evoked Potentials ( r = 0.703 P < 0.001) in tDCS+/rTMS- group. Conclusion: 1Hz rTMS combined with anode tDCS stimulation protocol could be a preferable rehabilitative strategy for motor recovery in subacute stroke patients.

Epistemic Uncertainties in Local Earthquake Locations and Implications for Managing Induced Seismicity

ABSTRACT Earthquake hypocentral location is perhaps the most classical problem in seismology, the solution of which is often affected by significant uncertainty. In monitoring the effects of underground anthropogenic activities, the earthquake hypocentral location, magnitude, and ground motions are important parameters for managing induced seismicity (as e.g., for operating traffic-light systems). Such decisional systems define the operative reactions to be enacted once an earthquake, exceeding some magnitude or ground-motion threshold, occurs within a monitoring volume defined in the neighborhood of a certain anthropogenic underground activity. In this case, a reliable evaluation of the hypocentral location, along with its uncertainty, becomes crucial for rational decision making. In this article, we analyze different sources of uncertainty that can be relevant for the determination of earthquake source locations, and introduce a logic-tree-based ensemble modeling approach for framing the problem in a decision-making context. To demonstrate the performance of the proposed approach, we analyze uncertainties in the location of a seismic event that occurred on 22 July 2019 within the perimeter of the monitoring domain defined in the Val d’Agri oil field (southern Italy). We cast the result as a model ensemble that allows us to obtain samples from a parent distribution that better represents both aleatory and epistemic uncertainties of the earthquake location problem. We find that often-neglected epistemic uncertainties (i.e., those that arise when considering alternative plausible modeling approaches or data) can be considerably larger and more representative of the state of knowledge about the source location, than the standard errors usually reported by the most common algorithms. Given the consequential repercussions of decision making under uncertainty, we stress that an objective evaluation of epistemic uncertainties associated with any parameter used to support decisional processes must be a priority for the scientific community.

The Feasibility of a Robotic Device to Objectively Measure Ankle Joint Proprioception

Proprioception is defined as the ability to sense limb and body position and motion. Proprioceptive signals originating from the mechanoreceptors around the ankle joint are critical for maintaining postural control and gait. Previous studies identified the detrimental effect of ankle somatosensory dysfunction on sensorimotor function such as balance control. However, a direct measure of ankle proprioception as a marker of proprioceptive dysfunction has not been identified. Recent advances in robotic rehabilitation devices allow precise movement of body segments while maintaining tight control over the exposed joint velocity. Here, we aim to design an ankle robot with 1-degree-of-freedom (DOF) – dorsiflexion/plantarflexion (DFPF) to objectively measure ankle joint proprioception in two aspects - joint position sense, and motion sense. To establish the feasibility of the device to evaluate ankle proprioceptive function, a small sample of healthy adult participants (n = 3) was recruited. A psychophysical 2-alternative forced-choice paradigm was employed for ankle position and motion sense evaluation. The ankle robot passively moved the ankle to one of two different positions or at two different stimulus velocities. Subsequently, participants verbally indicated the farthest position or the fastest motion. Based on their responses, a psychometric function was fitted, and a just-noticeable-difference (JND) threshold was established at the 75% correct response level, which served as a measure of ankle joint proprioception. The mean JND position threshold was 0.73°± 0.01°, and the mean JND motion threshold was 0.62°/s ± 0.05°/s. Test-retest reliability tests in all three subjects yielded the reliability coefficients of rT2 − T1 = 0.974 for JND position threshold, and rT2 − T1 = 0.948 for JND motion threshold. We here demonstrate that the feasibility and reliability of this new device to assess ankle proprioceptive acuity.

How does group differences in motion scrubbing affect false positives in functional connectivity studies?

Analyzing resting state fMRI data is difficult due to a weak signal and several noise sources. Head motion is also a major problem and it is common to apply motion scrubbing, i.e. to remove time points where a subject has moved more than some pre-defined motion threshold. A problem arises if one cohort on average moves more than another, since the remaining temporal degrees of freedom are then different for the two groups. The effect of this is that the uncertainty of the functional connectivity estimates (e.g. Pearson correlations) are different for the two groups, but this is seldom modelled in resting state fMRI. We demonstrate that group differences in motion scrubbing can result in inflated false positives, depending on how the temporal auto correlation is modelled when performing the Fisher r-to-z transform.

Two-dimensional numerical modeling of wood transport

The transport of wood material in rivers has been the subject of various studies in recent years. Most research has focused on the ecological and geomorphologic role of wood, its recruitment processes and spatial distribution in streams. In this study, we focused on wood transport dynamics, and we have developed a numerical model to simulate wood transport coupled with a two-dimensional (2D) hydrodynamic model. For this purpose, wood drag forces were incorporated as additional source terms into the shallow water equations, which are solved together with wood transport by using the finite volume method. This new tool has been implemented as a computational module into ‘Iber’, a 2D hydraulic simulation software. The new module analyzes the initial motion threshold of wood based on the balance of forces involved in the wood's movement, and computes the position and velocity of differently shaped logs using a kinematic approach. The method also considers the interaction between the logs themselves and between the logs and the channel walls or boundaries. Flume experiments were used in a straight channel with obstructions to validate the model's capacity to accurately reproduce the movement of floating logs.

A FEW TESTS ON THE MOTION-THRESHOLD OF SOLID GRAINS UNDER AN OSCILLATORY FLUID MOTION

A few remarks are made about the similarity of the conditions for the initiation of motion of sand grains on a bed when these grains are acted upon by either a steady flow or by waves.