Transcutaneous Spinal Direct Current Stimulation (tsDCS) Modulates Human Corticospinal System Excitability

This study aimed to assess the effects of thoracic anodal and cathodal transcutaneous spinal direct current stimulation (tsDCS) on upper- and lower-limb corticospinal excitability. Yet, despite studies assessing thoracic tsDCS influences the spinal ascending tract and reflexes, none assessed the effects of this technique over upper- and lower-limb corticomotorneuronal connections. In 14 healthy subjects we recorded motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) from abductor hallucis (AH) and hand abductor digiti minimi (ADM) muscles before (baseline, B), and at a different time-points (0 and 30 minutes) after anodal or cathodal tsDCS (2.5 mA, 20 minutes, T9-T11 level). In 8 of the 14 subjects we also tested the soleus H-reflex, the F-waves from AH and ADM before and after tsDCS. Both anodal and cathodal tsDCS left the upper-limb MEPs and F-wave unchanged. Conversely, while leaving lower-limb H-reflex unchanged, they oppositely affected lower-limb MEPs: whereas anodal tsDCS increased resting motor threshold (mean\ub1SEM 107.33 \ub1 3.3%, increase immediately after tsDCS, and 108.37 \ub1 3.2% increase 30 min after tsDCS compared to baseline), and had no effects on MEP area and latency, cathodal tsDCS increased MEP area (139.71 \ub1 12.9% increase immediately after tsDCS and 132.74 \ub122.0% increase 30 min after tsDCS compared to baseline) without affecting resting motor threshold and MEP latency. Our results show that tsDCS induces polarity specific changes in corticospinal excitability that last for more than 30 min after tsDCS offset and selectively affect responses in lower-limb muscles innervated by lumbar and sacral motorneurons

Correlazione tra sintomi di spettro psicotico e suicidalità in un campione di 147 pazienti con disturbi dell'umore

Introduzione: Il suicidio rappresenta la 15° causa di morte nel mondo con più di 800.000 morti nel 2012. Se a questo numero si aggiunge il dato dei tentati suicidi, stimato essere dieci volte superiore, si capisce il motivo per cui il suicidio, e la suicidalità in generale, sono da considerarsi importanti problemi di sanità pubblica. La prevenzione del suicidio si basa sul riconoscimento dei fattori di rischio, sulla diagnosi precoce di malattia mentale e sul tempestivo intervento terapeutico. I disturbi dell’umore sono i principali fattori di rischio per il suicidio. C’è un’ampia letteratura sulla correlazione tra disturbi dell’umore, sintomi psicotici e suicidio con conclusioni contraddittorie. Lo scopo di questo studio è quello di valutare la relazione tra suicidalità e le dimensioni minori dello spettro psicotico in soggetti con disturbi dell’umore e vedere se questo rappresenta un vantaggio nella valutazione del rischio di suicidio. Metodo: 147 pazienti con disturbi dell’umore consecutivamente afferenti agli ambulatori o ai reparti di ricovero di 11 Dipartimenti italiani di Psichiatria sono stati sottoposti a una intervista clinica strutturata per i disturbi di Asse I secondo il DSM-IV, alla intervista clinica strutturata per lo Spettro Psicotico (SCI-PSY) e all’auto-valutazione dello Spettro dell’umore (MOODS-SR). I partecipanti sono stati divisi in categorie come aventi disturbi dell’umore psicotici (PM) o non psicotici (NPM) rispetto alla presenza di delirio o allucinazioni. Risultati: Soggetti con suicidalità lifetime non mostravano una significativa più alta frequenza di PM. Tuttavia, mostravano punteggi significativamente più alti nello SCI-PSY totale (p<0.001) e ai domini Sensitività Interpersonale (p<0.001), Paranoide (p=0.002), Schizoide (p=0.005) e Sintomi Tipici (p=0.031). Controllando per età e sesso, il punteggio nel dominio Sensitività Interpersonale prediceva la suicidalità lifetime indipendentemente in entrambi, sia nei soggetti con PM (p=0.002) sia in quelli con NPM (p=0.001) mentre il punteggio nel dominio Paranoide prevedeva significativamente la suicidalità solo nei soggetti con PM (p=0.019) e il punteggio nel dominio Schizoide solo in pazienti con NPM (p=0.029). Limiti: Manca la valutazione dei disturbi di Asse II. La valutazione lifetime non permette di stabilire una sequenza temporale tra sintomi dello spettro psicotico e suicidalità. L’esclusione di soggetti con gravi malattie o abuso di sostanze può portare a sottostimare la suicidalità. Conclusioni: I tratti psicotici, valutati come presenza di delirio e allucinazioni, non sono associati con la suicidalità. Tuttavia, dimensioni più sottili dello spettro psicotico come la Sensitività Interpersonale, le dimensioni Paronoide e Schizoide mostrano una significativa relazione con la suicidalità. I nostri dati mettono in rilievo il vantaggio potenziale di un approccio di spettro nella valutazione del rischio di suicidio

Cerebellar Transcranial Direct Current Stimulation (ctDCS) Effect in Perception and Modulation of Pain

Transcranial direct stimulation (tDCS) in the treatment of intractable or marginally tractable pain is experiencing an increasing diffusion in many fields worldwide. Recently, new modality of tDCS application has been proposed and applied, as cerebellar transcranial direct current stimulation (ctDCS). Indeed, the cerebellum has been proved to play a role in pain processing and to be involved in a wide number of integrative functions. In this chapter, we encompass the history of the technique, analysis of principles, a general description, including the methodological procedures of ctDCS; then, main clinical applications and their main effects in perceptive threshold of pain and other sensation, pain intensity, and laser evoked potentials (LEPs) changes

High-resolution ultrasound changes of the vagus nerve in idiopathic Parkinson’s disease (IPD): a possible additional index of disease

Background and rationale: Histopathological studies revealed degeneration of the dorsal motor nucleus of the vagus nerve (VN) early in the course of idiopathic Parkinson’s disease (IPD). Degeneration of VN axons should be detectable by high-resolution ultrasound (HRUS) as a thinning of the nerve trunk. In order to establish if the VN exhibits sonographic signs of atrophy in IPD, we examined patients with IPD compared with age-matched controls. Material and methods: We measured the caliber (cross-sectional area, CSA) and perimeter of the VN in 20 outpatients with IPD (8 females and 12 males; mean age 73.0 + 8.6 years) and in age-matched controls using HRUS. Evaluation was performed by blinded raters using an Esaote MyLab Gamma device in conventional B-Mode with an 8–19 MHz probe. Results: In both sides, the VN CSA was significantly smaller in IPD outpatients than in controls (right 2.37 + 0.91, left 1.87 + 1.35 mm2 versus 6.0 + 1.33, 5.6 + 1.26 mm2; p &lt;0.001), as well as the perimeter (right 5.06 + 0.85, left 4.78 + 1.74 mm versus 8.87 + 0.86, 8.58 + 0.97 mm; p &lt;0.001). There were no significant correlations between VN CSA and age, the Hoehn and Yahr scale, L-dopa therapy, and disease duration. Conclusion: Our findings provide evidence of atrophy of the VNs in IPD patients by HRUS. Moreover, HRUS of the VN represent a non-invasive easy imaging modality of screening in IPD patients independent of disease stage and duration and an interesting possible additional index of disease

Cerebellar Direct Current Stimulation (ctDCS) in the Treatment of Huntington's Disease: A Pilot Study and a Short Review of the Literature

Introduction: In recent years, a growing body of literature has investigated the use of non-invasive brain stimulation (NIBS) techniques as a putative treatment in Huntington's Disease (HD). Our aim was to evaluate the effects of cerebellar transcranial Direct Current Simulation (ctDCS) on the motor outcome in patients affected by HD, encompassing at the same time the current knowledge about the effects of NIBS both on motor and non-motor dysfunctions in HD. Materials and Methods: Four patients (two females) were enrolled and underwent ctDCS (both anodal or sham, elapsed by at least 3 months: 2.0 mA, 20 min per day, 5 days a week). Clinical scores were assessed by using the Unified Huntington's Disease Rating Scale – part I (UHDRS-I), immediately before ctDCS (T0), at the end of the 5-days treatment (T1) and 4 weeks later (T2). Results: Anodal ctDCS improved motor scores compared to baseline (p = 0.0046), whereas sham stimulation left them unchanged (p = 0.33, Friedman test). In particular, following anodal ctDCS, UHDRS-I score significantly improved, especially regarding the subitem “dystonia,” both at T1 and T2 compared to sham condition (p &lt; 0.05; Wilcoxon matched-pairs signed test). Conclusions: ctDCS improved motor scores in HD, with effects lasting for about 4 weeks after tDCS completion. This is the first study discussing the putative role of cerebellar non-invasive simulation for the treatment of HD

Color perception deficits in co-existing attention-deficit/hyperactivity disorder and chronic tic disorders

Preliminary findings suggest that color perception, particularly of blue-yellow stimuli, is impaired in attention-deficit/hyperactivity disorder (ADHD) as well as in chronic tic disorders (CTD). However, these findings have been not replicated and it is unclear what these deficits mean for the comorbidity of ADHD + CTD. Four groups (ADHD, CTD, ADHD + CTD, controls) of children with similar age, IQ and gender distribution were investigated with the Farnsworth-Munsell 100 Hue Test (FMT) and the Stroop-Color-Word Task using a factorial design. Color perception deficits, as indexed by the FMT, were found for both main factors (ADHD and CTD), but there were no interaction effects. A preponderance of deficits on the blue-yellow compared to the red-green axis was detected for ADHD. In the Stroop task only the 'pure' ADHD group showed impairments in interference control and other parameters of Stroop performance. No significant correlations between any FMT parameter and color naming in the Stroop task were found. Basic color perception deficits in both ADHD and CTD could be found. Beyond that, it could be shown that these deficits are additive in the case of comorbidity (ADHD + CTD). Performance deficits on the Stroop task were present only in the 'pure' ADHD group. Hence, the latter may be compensated in the comorbid group by good prefrontal capabilities of CTD. The influence of color perception deficits on Stroop task performance might be negligible. © 2007 Springer-Verlag

Unilateral Application of Cathodal tDCS Reduces Transcallosal Inhibition and Improves Visual Acuity in Amblyopic Patients

Objective: Amblyopia is a neurodevelopmental disorder characterized by visual acuity and contrast sensitivity loss, refractory to pharmacological and optical treatments in adulthood. In animals, the corpus callosum (CC) contributes to suppression of visual responses of the amblyopic eye. To investigate the role of interhemispheric pathways in amblyopic patients, we studied the response of the visual cortex to transcranial Direct Current Stimulation (tDCS) applied over the primary visual area (V1) contralateral to the "lazy eye." Methods: Visual acuity (logMAR) was assessed before (T0), immediately after (T1) and 60' following the application of cathodal tDCS (2.0 mA, 20') in 12 amblyopic patients. At each time point, Visual Evoked Potentials (VEPs) triggered by grating stimuli of different contrasts (K90%, K20%) were recorded in both hemispheres and compared to those obtained in healthy volunteers. Results: Cathodal tDCS improved visual acuity respect to baseline (p &lt; 0.0001), whereas sham polarization had no significant effect. At T1, tDCS induced an inhibitory effect on VEPs amplitudes at all contrasts in the targeted side and a facilitation of responses in the hemisphere ipsilateral to the amblyopic eye; compared with controls, the facilitation persisted at T2 for high contrasts (K90%; Holm-Sidak post hoc method, p &lt; 0.001), while the stimulated hemisphere recovered more quickly from inhibition (Holm-Sidak post hoc method, p &lt; 0.001). Conclusions: tDCS is a promising treatment for amblyopia in adults. The rapid recovery of excitability and the concurrent transcallosal disinhibition following perturbation of cortical activity may support a critical role of interhemispheric balance in the pathophysiology of amblyopia