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Objective/hypothesis: Transcranial direct current stimulation (tDCS) is a potential tool to improve motor recovery in patients with neurological disorders. Safety and efficacy of this procedure for lower extremity motor strengthe and gait function in motor incomplete spinal cord injury (SCI) have not yet been addressed. The aim of this study is to optimize the functional outcome in early phases of gait rehabilitation assisted by Lokomat(®) in motor incomplete SCI patients using tDCS as an additional treatment to physical therapy., Methods: We performed in a SCI unit a single-centre randomized, double-blind, sham-controlled study to investigate safety and efficacy of anodal tDCS of over leg motor cortex in motor incomplete SCI patients. Twenty-four SCI patients received either daily sessions of anodal tDCS (n=12) at 2mA for 20min to the vertex (leg motor cortex) during twenty days or sham tDCS (n=12). Motor deficit was assessed by the lower extremity motor score (LEMS) and for gait function: ten meter walking test (10MWT) and Walking Index for SCI (WISCI II) at baseline, after last tDCS session (after 4 weeks of stimulation), and after 8 weeks (from baseline) for follow-up., Results: No side effects were detected during either tDCS or sham. In both groups, there was a significant improvement in LEMS (p<0.03), which did not significantly differ when comparing anodal and sham tDCS groups. During follow-up, in both group 5 of 12 patients could perform gait, without significant differences in gait velocity, cadence, step length and WISCI-II between both groups., Conclusion: Combination twenty sessions of daily tDCS to the leg motor cortex and Lokomat(®) gait training appear to be safe in motor incomplete SCI patients. There was an expected improvement in both LEMS and gait scales however, did not differ between patients treated with anodal or sham tDCS., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Repetitive magnetic stimulation (rMS) modulates thermal somatosensory function at both low (0.2-1.0Hz) and high (5.0-20.0Hz) frequencies within the conditioned dermatome. However the effects of 1Hz and 20Hz cervical (C6-C7) rMS on thermosensory thresholds and contact heat evoked potentials (CHEPs) tested within local and remote spinal dermatomes are not known., Methods: Thirty healthy subjects participated in the study. Warm and cold detection threshold, heat and cold pain thresholds, and Cz/Fz CHEPs were evaluated within the C6, T10 and extrasegmental V3 control dermatome, before and after random assignment of subjects to sham, 1 or 20Hz C6-C7 rMS., Results: Following both 1 and 20Hz cervical rMS, warm detection threshold increased within the local C6 dermatome. Furthermore 1Hz cervical rMS increased warm detection threshold within the remote T10 dermatome, but not within the V3-trigeminal control area. Cervical rMS failed to modulate cold detection threshold, heat and cold pain threshold or Cz/Fz CHEP amplitude from the dermatomal test sites., Conclusion: Both 1 and 20Hz cervical rMS modulated warm detection threshold within the locally conditioned C6 dermatome. The concomitant increase in warm detection threshold within the T10 dermatome following 1Hz rMS provides evidence for remote neuromodulation of thermosensory function via intraspinal control mechanisms., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

The size of the response to a startling auditory stimulus (SAS) may reflect the excitability of the reticulospinal tract. In this study, we examined whether there was any excitability change in the reticulospinal tract during preparation for execution of two types of choice reaction time task: a forced choice reaction time task (fCRT) and a Go/no-Go task (GnG). In 13 healthy volunteers we used three types of trials: control trials in which subjects were requested to perform ballistic wrist movements during fCRT or GnG tasks; test trials in which a SAS was presented with the visual cue, and baseline trials in which SAS was presented alone. Latency and area of the responses to SAS were measured in the orbicularis oculi and in the sternocleidomastoid (SCM) muscles. The results obtained in baseline trials were used to calculate the mean resting baseline excitability level of the reticulospinal tract for each individual, and the values obtained in test trials were expressed as percentages of mean baseline for normalization of data from all individuals. The area of the responses to SAS in SCM was significantly larger in fCRT than in GnG (p=0.002). There was a significant shortening of reaction time in test trials that was inversely correlated with area of SCM (p<0.05). We conclude that the subcortical motor tracts activated by SAS are more excitable during fCRT tasks than GnG tasks. Changing the excitability of subcortical motor structures may be a strategy used by the central nervous system in motor control that is selected according to the motor program.

One of the clinical characteristics of psychogenic tremors (PT) is the disruption or transient cessation of tremor with distractive manoeuvres, including those involving the performance of voluntary movements with the contralateral hand. Seven patients with PT, 11 patients with Parkinson's disease (PD), 10 patients with essential tremor (ET) and 10 normal volunteers mimicking tremor (NV) were requested to perform a fast unilateral wrist movement to close a switch, at the perception of a visual cue, either at rest or during maintenance of a posture. We measured the time-locked changes in frequency and amplitude occurring in tremor oscillations of the contralateral hand. The reaction time task induced a significant reduction in amplitude or cessation of contralateral tremor oscillations in PT and NV, but not in PD and ET. The effect occurred with a delay with respect to the onset of the contralateral movement without significant differences in PT versus NV (p > 0.05). The physiological mechanisms accounting for the effect seen on tremor of NV and PT may involve the interhemispheric inhibition that accompanies the execution of a unilateral motor task. Tremor circuits in patients with PD and ET may be impervious to these inhibitory commands. The documentation and quantitation of the effects of a ballistic movement on contralateral rhythmic activity are of clinical relevance for the identification of patients with PT.