Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke

Gall, Carolin; Silvennoinen, Katri; Granata, Giuseppe; Rossi, Francesca; Vecchio, Fabrizio; Brösel, Doreen; Bola, Michał; Sailer, Michael; Waleszczyk, Wioletta J.; Rossini, Paolo Maria; Tatlısumak, Turgut; Sabel, Bernhard A.

doi:10.1016/j.cct.2015.06.005

Cited by 28 publications

(22 citation statements)

References 46 publications

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“…60–90 min (Gall et al, 2016). To date, 760 patients with optic neuropathies, e.g., following stroke or with postchiasmatic lesions, have been treated in various clinical trials using this technology (Fedorov et al, 2011; Gall et al, 2013, 2010, 2016, 2011, 2015; Sabel et al, 2011; Schmidt et al, 2013). The most common AEs were skin sensations and irritation, headache, drowsiness, and sleep disturbances.…”

Section: The Application Of Low Intensity Tes In Human Studies: Aementioning

confidence: 99%

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Antal

Alekseichuk

Bikson

et al. 2017

Clinical Neurophysiology

933

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Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1–2 mA and during tACS at higher peak-to-peak intensities above 2 mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity ‘conventional’ TES defined as <4 mA, up to 60 min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3–13 A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10 mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6–7, 2016 and were refined thereafter by email correspondence.

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Section: The Application Of Low Intensity Tes In Human Studies: Aementioning

confidence: 99%

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Antal

Alekseichuk

Bikson

et al. 2017

Clinical Neurophysiology

933

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“…35 An improvement in acuity has recently been demonstrated following anodal tDCS, 36 but another study did not find any effect of tDCS on visual cortex excitability. 37 While there have been single case studies of tDCS stimulation in patients with hemianopia, 38 and a proposed clinical trial, 39 there is currently little data to determine how beneficial tDCS might be for visual rehabilitation. The current study is preliminary, but none of the three patients who received anodal tDCS showed any improvement in visual motion direction discrimination.…”

Section: Transcranial Direct Current Stimulation Does Not Affect Visumentioning

confidence: 99%

Visual training in hemianopia alters neural activity in the absence of behavioural improvement: a pilot study

Larcombe

Kulyomina

Antonova

et al. 2018

Ophthalmic Physiologic Optic

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BackgroundDamage to the primary visual cortex (V1) due to stroke often results in permanent loss of sight affecting one side of the visual field (homonymous hemianopia). Some rehabilitation approaches have shown improvement in visual performance in the blind region, but require a significant time investment.MethodsSeven patients with cortical damage performed 400 trials of a motion direction discrimination task daily for 5 days. Three patients received anodal transcranial direct current stimulation (tDCS) during training, three received sham stimulation and one had no stimulation. Each patient had an assessment of visual performance and a functional magnetic resonance imaging (fMRI) scan before and after training to measure changes in visual performance and cortical activity.ResultsNo patients showed improvement in visual function due to the training protocol, and application of tDCS had no effect on visual performance. However, following training, the neural response in motion area hMT+ to a moving stimulus was altered. When the stimulus was presented to the sighted hemifield, activity decreased in hMT+ of the damaged hemisphere. There was no change in hMT+ response when the stimulus was presented to the impaired hemifield. There was a decrease in activity in the inferior precuneus after training when the stimulus was presented to either the impaired or sighted hemifield. Preliminary analysis of tDCS data suggested that anodal tDCS interacted with the delivered training, modulating the neural response in hMT+ in the healthy side of the brain.ConclusionTraining can affect the neural responses in hMT+ even in the absence of change in visual performance.

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“…Investigators have attempted to quantify the nature of tDCS effects on physiology using EEG (e.g., (Gall et al, 2015; Reinhart & Woodman, 2015; Reinhart, Zhu, Park, & Woodman, 2015)), fMRI (e.g., (Alekseichuk, Diers, Paulus, & Antal, 2015; Amadi, Ilie, Johansen-Berg, & Stagg, 2013; Antal, Polania, Schmidt-Samoa, Dechent, & Paulus, 2011; Hilgenstock, Weiss, Huonker, & Witte, 2016; Hunter et al, 2015; Spiegel et al, 2013)), and MEG (Garcia-Cossio et al, 2015; Hanley, Singh, & McGonigle, 2015; Marshall, Esterer, Herring, Bergmann, & Jensen, 2015; Soekadar et al, 2013). However, there has been little consensus across studies, especially those with similar task parameters.…”

Section: Introductionmentioning

confidence: 99%

Transcranial direct-current stimulation modulates offline visual oscillatory activity: A magnetoencephalography study

Heinrichs‐Graham

McDermott²,

Mills³

et al. 2017

Cortex

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Transcranial direct-current stimulation (tDCS) is a noninvasive neuromodulatory method that involves delivering low amplitude, direct current to specific regions of the brain. While a wealth of literature shows changes in behavior and cognition following tDCS administration, the underlying neuronal mechanisms remain largely unknown. Neuroimaging studies have generally used fMRI and shown only limited consensus to date, while the few electrophysiological studies have reported mostly null or counterintuitive findings. The goal of the current investigation was to quantify tDCS-induced alterations in the oscillatory dynamics of visual processing. To this end, we performed either active or sham tDCS using an occipital-frontal electrode configuration, and then recorded magnetoencephalography (MEG) offline during a visual entrainment task. Significant oscillatory responses were imaged in the time-frequency domain using beamforming, and the effects of tDCS on absolute and relative power were assessed. The results indicated significantly increased basal alpha levels in the occipital cortex following anodal tDCS, as well as reduced occipital synchronization at the second harmonic of the stimulus-flicker frequency relative to sham stimulation. In addition, we found reduced power in brain regions near the cathode (e.g., right inferior frontal gyrus) following active tDCS, which was absent in the sham group. Taken together, these results suggest that anodal tDCS of the occipital cortices differentially modulates spontaneous and induced activity, and may interfere with the entrainment of neuronal populations by a visual-flicker stimulus. These findings also demonstrate the importance of electrode configuration on whole-brain dynamics, and highlight the deceptively complicated nature of tDCS in the context of neurophysiology.

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Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke

Cited by 28 publications

References 46 publications

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Visual training in hemianopia alters neural activity in the absence of behavioural improvement: a pilot study

Transcranial direct-current stimulation modulates offline visual oscillatory activity: A magnetoencephalography study

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