Computer vision-based algorithm to sUppoRt coRrect electrode placemeNT (CURRENT) for home-based electric non-invasive brain stimulation.

OBJECTIVE: Home-based non-invasive brain stimulation (NIBS) has been suggested as an adjunct treatment strategy for neuro-psychiatric disorders. There are currently no available solutions to direct and monitor correct placement of the stimulation electrodes. To address this issue, we propose an easy-to-use digital tool to support patients for self-application. METHODS: We recruited 36 healthy participants and compared their cap placement performance with the one of a NIBS-expert investigator. We tested participants' placement accuracy with instructions before (Pre) and after the investigator's placement (Post), as well as participants using the support tool (CURRENT). User experience (UX) and confidence were further evaluated. RESULTS: Permutation tests demonstrated a smaller deviation within the CURRENT compared with Pre cap placement (p = 0.02). Subjective evaluation of ease of use and usefulness of the tool were vastly positive (8.04 out of 10). CURRENT decreased the variability of performance, ensured placement within the suggested maximum of deviation (10 mm) and supported confidence of correct placement. CONCLUSIONS: This study supports the usability of this novel technology for correct electrode placement during self-application in home-based settings. SIGNIFICANCE: CURRENT provides an exciting opportunity to promote home-based, self-applied NIBS as a safe, high-frequency treatment strategy that can be well integrated in patients' daily lives.

Examining the synergistic effects of a cognitive control video game and a home-based, self-administered non-invasive brain stimulation on alleviating depression: the DiSCoVeR trial protocol.

Enhanced behavioral interventions are gaining increasing interest as innovative treatment strategies for major depressive disorder (MDD). In this study protocol, we propose to examine the synergistic effects of a self-administered home-treatment, encompassing transcranial direct current stimulation (tDCS) along with a video game based training of attentional control. The study is designed as a two-arm, double-blind, randomized and placebo-controlled multi-center trial (ClinicalTrials.gov: NCT04953208). At three study sites (Israel, Latvia, and Germany), 114 patients with a primary diagnosis of MDD undergo 6 weeks of intervention (30 × 30 min sessions). Patients assigned to the intervention group receive active tDCS (anode F3 and cathode F4; 2 mA intensity) and an action-like video game, while those assigned to the control group receive sham tDCS along with a control video game. An electrode-positioning algorithm is used to standardize tDCS electrode positioning. Participants perform their designated treatment at the clinical center (sessions 1-5) and continue treatment at home under remote supervision (sessions 6-30). The endpoints are feasibility (primary) and safety, treatment efficacy (secondary, i.e., change of Montgomery-Åsberg Depression Rating Scale (MADRS) scores at week six from baseline, clinical response and remission, measures of social, occupational, and psychological functioning, quality of life, and cognitive control (tertiary). Demonstrating the feasibility, safety, and efficacy of this novel combined intervention could expand the range of available treatments for MDD to neuromodulation enhanced interventions providing cost-effective, easily accessible, and low-risk treatment options.ClinicalTrials.gov: NCT04953208.

Low-Intensity Focused Ultrasound Neuromodulation for Stroke Recovery: A Novel Deep Brain Stimulation Approach for Neurorehabilitation?

Stroke as the leading cause of adult long-term disability and has a significant impact on patients, society and socio-economics. Non-invasive brain stimulation (NIBS) approaches such as transcranial magnetic stimulation (TMS) or transcranial electrical stimulation (tES) are considered as potential therapeutic options to enhance functional reorganization and augment the effects of neurorehabilitation. However, non-invasive electrical and magnetic stimulation paradigms are limited by their depth focality trade-off function that does not allow to target deep key brain structures critically important for recovery processes. Transcranial ultrasound stimulation (TUS) is an emerging approach for non-invasive deep brain neuromodulation. Using non-ionizing, ultrasonic waves with millimeter-accuracy spatial resolution, excellent steering capacity and long penetration depth, TUS has the potential to serve as a novel non-invasive deep brain stimulation method to establish unprecedented neuromodulation and novel neurorehabilitation protocols. The purpose of the present review is to provide an overview on the current knowledge about the neuromodulatory effects of TUS while discussing the potential of TUS in the field of stroke recovery, with respect to existing NIBS methods. We will address and discuss critically crucial open questions and remaining challenges that need to be addressed before establishing TUS as a new clinical neurorehabilitation approach for motor stroke recovery.

Evaluation of a shortened version of the Action Research Arm Test (ARAT) for upper extremity function after stroke: The Mini-ARAT.

OBJECTIVES: (i) to create a shortened version of the Action Research Arm Test scale, (ii) to investigate its psychometric properties compared to the original scale and (iii) to externally validate it within an independent cohort. DESIGN: Prospective longitudinal cohort study. SETTINGS: Two University Hospitals (France, Switzerland). PARTICIPANTS: 47 patients with poststroke motor deficits of the upper limb coming from two different sites were included and divided into two cohorts (n = 22 for the construction cohort; n = 25 for the validation cohort). MAIN MEASURES: We used the first cohort to build the Mini-ARAT by shortening the Action Research Arm Test scale on the basis of ceiling/floor effects and collinearity of the subscales. We studied its reliability, validity, and responsiveness and performed an external validation with the second cohort. RESULTS: The Mini-ARAT consisted of 2 subscales from the original Action Research Arm Test scale (Grip and Pinch). Internal consistency (α = 87) and inter-rater reliability (0.99, 95% CI: 0.98-0.99, p < 0.01) were good and similar to those of the Action Research Arm Test scale. The Minimal Clinically Important Difference of the Mini-ARAT was 9 points. The predictive validity in the construction and validation cohorts showed good correlation between the Mini-ARAT at baseline and the Fugl Meyer at 3 months (rho, 95% CI: 0.77, 0.49-0.90, p < 0.01, and 0.58, 0.19-0.96, p < 0.01). CONCLUSION: The Mini-ARAT is a time-effective tool able to capture the dynamics of motor deficits with high reliability and consistency, providing excellent information about residual motor functions, which is critically important for clinical and research purposes.

Perspectives: Hemianopia-Toward Novel Treatment Options Based on Oscillatory Activity?

Stroke has become one of the main causes of visual impairment, with more than 15 million incidences of first-time strokes, per year, worldwide. One-third of stroke survivors exhibit visual impairment, and most of them will not fully recover. Some recovery is possible, but this usually happens in the first few weeks after a stroke. Most of the rehabilitation options that are offered to patients are compensatory, such as optical aids or eye training. However, these techniques do not seem to provide a sufficient amount of improvement transferable to everyday life. Based on the relatively recent idea that the visual system can actually recover from a chronic lesion, visual retraining protocols have emerged, sometimes even in combination with noninvasive brain stimulation (NIBS), to further boost plastic changes in the residual visual tracts and network. The present article reviews the underlying mechanisms supporting visual retraining and describes the first clinical trials that applied NIBS combined with visual retraining. As a further perspective, it gathers the scientific evidence demonstrating the relevance of interregional functional synchronization of brain networks for visual field recovery, especially the causal role of α and γ oscillations in parieto-occipital regions. Because transcranial alternating current stimulation (tACS) can induce frequency-specific entrainment and modulate spike timing-dependent plasticity, we present a new promising interventional approach, consisting of applying physiologically motivated tACS protocols based on multifocal cross-frequency brain stimulation of the visuoattentional network for visual field recovery.

Interhemispheric motor networks are abnormal in patients with Gilles de la Tourette syndrome.

Brain imaging has shown altered corpus callosum (CC) morphology in patients with Gilles de la Tourette syndrome (GTS). Yet it is unclear whether these morphological changes are associated with altered interhemispheric interactions. Here, we combined transcranial magnetic stimulation (TMS) with diffusion tensor magnetic resonance imaging (DTI) to explore functional and structural interhemispheric connections between the left and right motor hand areas. We studied 14 unmedicated GTS patients without psychiatric comorbidity (2 women, mean age 35.5 years) and 15 healthy volunteers (3 women, mean age 35 years). Left-to-right and right-to-left interhemispheric inhibitions (IHIs) were measured in hand muscles with TMS. In 13 GTS patients and all healthy controls, we measured fractional anisotropy (FA) with DTI to examine the relation between functional measures of interhemispheric connectivity as derived by TMS and structural properties of the CC region that carries fibers interconnecting both motor cortices. In GTS patients, left-to-right IHI was weaker than right-to-left IHI. Left-to-right IHI in GTS patients was also reduced compared with healthy controls. Voxel-based morphometric analysis revealed that FA in the motor region of the CC did not differ between groups. However, there was a significant interaction between groups and the relation between regional FA and left-to-right IHI in the motor region of the CC. A negative linear relation between FA and left-to-right IHI was present in control subjects but not in patients. Our combined TMS-DTI approach demonstrates abnormal functional interhemispheric connectivity in GTS accompanied by an altered structure-function relationship in the motor CC.