Five-day course of paired associative stimulation fails to improve motor function in stroke patients.

BACKGROUND: Non-invasive brain stimulation has been studied as a therapeutic adjunct for upper-limb recovery in patients with stroke. One type of stimulation, paired associative stimulation (PAS), has effects on plasticity in both patients and healthy participants. Lasting several hours, these effects are reversible and topographically specific. OBJECTIVE: The goal was to investigate the presence of a lasting increase in motor cortex plasticity for extensor wrist muscles - extensor carpi radialis (ECR) - and an improvement in upper-limb function after 5 days of daily PAS in patients at the subacute post-stroke stage. METHODS: A total of 24 patients (mean [SD] age 50.1 [12.1] years, weeks since stroke 10.1 [5.3]) were included in a double-blind, placebo-controlled trial and randomly assigned to the PAS or sham group (n=13 and n=11). For the PAS group, patients underwent a 5-day course of electrical peripheral stimulation combined with magnetic cortical stimulation applied to the ECR muscle in a single daily session at 0.1Hz for 30min; patients with sham treatment received minimal cortical stimulation. Both patient groups underwent 2 hr of conventional physiotherapy. Variations in the motor evoked potential (MEP) surface area of the ECR muscle and Fugl-Meyer Assessment-Upper-Limb motor scores were analysed up to day 12. RESULTS: The 2 groups did not differ in electrophysiological or motor parameters. Repeated PAS sessions seemed to affect only patients with low initial cortical excitability. We found considerable variability in PAS effects between patients and across the sessions. CONCLUSION: We failed to induce a lasting effect with PAS in the present study. PAS does not seem to be the main method for post-stroke brain stimulation. Perhaps recruitment of patients could be more selective, possibly targeting those with a wide altered ipsilesional corticomotor pathway.

N270 sensitivity to conflict strength and working memory: A combined ERP and sLORETA study.

The event-related potential N270 component is known to be an electrophysiological marker of the supramodal conflict processing. However little is know about the factors that may modulate its amplitude. In particular, among all studies that have investigated the N270, little or no control of the conflict strength and of the load in working memory have been done leaving a lack in the understanding of this component. We designed a spatial audiovisual conflict task with simultaneous target and cross-modal distractor to evaluate the N270 sensitivity to the conflict strength (i.e., visual target with auditory distractor or auditory target with visual distractor) and the load in working memory (goal task maintenance with frequent change in the target modality). In a first session, participants had to focus on one modality for the target position to be considered (left-hand or right-hand) while the distractor could be at the same side (compatible) or at opposite side (incompatible). In a second session, we used the same set of stimuli as in the first session with an additional distinct auditory signal that clued the participants to frequently switch between the auditory and the visual targets. We found that (1) reaction times and N270 amplitudes for conflicting situations were larger within the auditory target condition compared to the visual one, (2) the increase in target maintenance effort led to equivalent increase of both reaction times and N270 amplitudes within all conditions and (3) the right dorsolateral prefrontal cortex current density was higher for both conflicting and active maintenance of the target situations. These results provide new evidence that the N270 component is an electrophysiological marker of the supramodal conflict processing that is sensitive to the conflict strength and that conflict processing and active maintenance of the task goal are two functions of a common executive attention system.

Sacral neuromodulation for treating neurogenic bladder dysfunction: clinical and urodynamic study.

PURPOSE: The efficacy of sacral neuromodulation for treating refractory idiopathic lower urinary tract dysfunction is now well established. Nevertheless, results of this technique in neurological patients are still controversial. The aim of this retrospective study was to assess the results of sacral neuromodulation in neurogenic bladder dysfunction. MATERIALS AND METHODS: Between 1998 and 2008, a percutaneous nerve evaluation or a two-stage technique was performed in 62 patients (mean age 50.5 ± 14.8 years) with neurogenic lower urinary tract dysfunction. Before and during the temporary stimulation, each patient had a urodynamic evaluation and performed a bladder diary. The test was considered positive if the clinical and urodynamic improvement was over 50% and if the symptoms reappeared after turning the stimulation off. RESULTS: Lower urinary tract dysfunction was detrusor overactivity in 34 cases and chronic urinary retention in 28 cases. A detrusor-sphincter dyssynergia (DSD) was associated in nine cases. Out of the 62 patients, 41 patients (66.1%) had more than 50% improvement on urodynamic evaluation and bladder diary and 37 were implanted. With a mean follow-up of 4.3 ± 3.7 years, results remained similar to the evaluation phase in 28 cases (75.7%), were partially altered in three cases (8.1%) and lost in six cases (16.2%). In these six cases, neuromodulation failed on average 12.0 ± 12.4 months after implantation. CONCLUSION: Sacral neuromodulation seems to constitute a serious therapeutic option for patients with neurogenic lower urinary tract dysfunction. However, its results depend on the type of the underlying neurologic disease and in particular, whether it may progress or not.

[Crenobalneotherapy: a medical and scientific update]. / Médecine thermale: actualités médicales et scientifiques.

The PubMed database contains about eighty scientific papers on crenobalneotherapy (i.e., medical balneology or spa therapy) published in the last three years, mostly in journals with an impact factor. These studies focus on the actions of thermomineral products (waters, muds, gases, steam) on biological systems (immune system, antioxidant system, cytokine networks, nociception, etc.). Hot mineral waters can have an action on the circulatory system. Ingested mineral water can act on carbohydrate, lipid and mineral metabolism. Dermocosmetologic mineral products have shown real benefits. Medical benefits of thermal treatment have been observed in patients with rheumatic conditions, psoriasis, venous insufficiency, ENT conditions, gynecolgical disorders, and anxiety. Unfortunately, many publications in this area suffer from methodological flaws. Clinical investigations of thermal medicine encounter dificulties of a methodological and financial nature, and problems of patient recruitment. The aim of the French thermal research institute is to provide support and advice for teams wishing to conduct well-designed controlled trials.

Induction of cortical plastic changes in wrist muscles by paired associative stimulation in the recovery phase of stroke patients.

BACKGROUND: Paired associative stimulation (PAS) combining peripheral nerve and transcranial magnetic stimulation (TMS) have been proposed to induce long-term changes in excitability of the cerebral cortex and potentially optimize motor recovery in stroke patients. OBJECTIVE: This pilot study examined whether short-lasting changes in cortical excitability could be induced by a single session of PAS within the first months after stroke. METHODS: Six hemiparetic patients with a subcortical stroke were included. The single session PAS protocol was applied at 1, 5, and 12 months after stroke. During the follow-up, the clinical recovery of wrist function was assessed in parallel to the PAS study by the Fugl-Meyer motor scale and dynamometry of wrist extension. RESULTS: The PAS protocol induced a significant extensor carpi radialis motor evoked potential facilitation (mean +78.5%) on the paretic side 5 months after stroke. The facilitation was still present 12 months after stroke but on average smaller (+30 %). CONCLUSIONS: These electrophysiological findings suggest that patients with subcortical infarcts may respond to PAS in an earlier than later period after stroke. If the clinical efficacy of interventions such as PAS is confirmed, it could be proposed early as add-on therapy to optimize training-induced plasticity processes.