scholarly journals Taking Sides: An Integrative Review of the Impact of Laterality and Polarity on Efficacy of Therapeutic Transcranial Direct Current Stimulation for Anomia in Chronic Poststroke Aphasia

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
Margaret Sandars ◽  
Lauren Cloutman ◽  
Anna M. Woollams
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Language Production ◽  
Right Hemisphere ◽  
Combined Therapy ◽  
Future Research ◽  
Language Therapy ◽  
Direct Current Stimulation ◽  
The Right ◽  
The Impact

Anomia is a frequent and persistent symptom of poststroke aphasia, resulting from damage to areas of the brain involved in language production. Cortical neuroplasticity plays a significant role in language recovery following stroke and can be facilitated by behavioral speech and language therapy. Recent research suggests that complementing therapy with neurostimulation techniques may enhance functional gains, even amongst those with chronic aphasia. The current review focuses on the use of transcranial Direct Current Stimulation (tDCS) as an adjunct to naming therapy for individuals with chronic poststroke aphasia. Our survey of the literature indicates that combining therapy with anodal (excitatory) stimulation to the left hemisphere and/or cathodal (inhibitory) stimulation to the right hemisphere can increase both naming accuracy and speed when compared to the effects of therapy alone. However, the benefits of tDCS as a complement to therapy have not been yet systematically investigated with respect to site and polarity of stimulation. Recommendations for future research to help determine optimal protocols for combined therapy and tDCS are outlined.

Anodal transcranial direct current stimulation over the right hemisphere improves auditory comprehension in a case of dementia

2017 ◽  
Vol 41 (2) ◽  
pp. 567-575 ◽  
Author(s):  
Vanessa Costa ◽  
Filippo Brighina ◽  
Tommaso Piccoli ◽  
Sabrina Realmuto ◽  
Brigida Fierro
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Right Hemisphere ◽  
Auditory Comprehension ◽  
Direct Current Stimulation ◽  
The Right

scholarly journals Differences in functional connectivity distribution after transcranial direct-current stimulation: a connectivity density point of view

2020 ◽  
Author(s):  
Bohao Tang ◽  
Yi Zhao ◽  
Archana Venkataraman ◽  
Kyrana Tsapkini ◽  
Martin A Lindquist ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Progressive Aphasia ◽  
Point Of View ◽  
Language Therapy ◽  
Post Intervention ◽  
Direct Stimulation ◽  
Direct Current Stimulation ◽  
The Impact

AbstractIn this manuscript we consider the problem of relating functional connectivity measurements viewed as statistical distributions to outcomes. We demonstrate the utility of using the distribution of connectivity on a study of resting state functional magnetic resonance imaging association with an intervention. Specifically, we consider 47 primary progressive aphasia (PPA) patients with various levels of language abilities. These patients were randomly assigned to two treatment arms, tDCS (transcranial direct-current stimulation and language therapy) vs sham (language therapy only), in a clinical trial. We propose a novel approach to analyze the effect of direct stimulation on functional connectivity. We estimate the density of correlations among the regions of interest (ROIs) and study the difference in the density post-intervention between treatment arms. We discover that it is the tail of the density, rather than the mean or lower order moments of the distribution, that demonstrates a significant impact in the classification. This approach has several benefits. Among them, it drastically reduces the number of multiple comparisons compared to edge-wise analysis. In addition, it allows for the investigation of the impact of functional connectivity on the outcomes where the connectivity is not geometrically localized.

scholarly journals Transcranial Direct Current Stimulation over the Right Inferior Parietal Cortex Reduces Transposition Errors in a Syllabic Reordering Task

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2077
Author(s):  
Vanessa Costa ◽  
Giuseppe Giglia ◽  
Simona Talamanca ◽  
Chiara Finocchiaro ◽  
Giuseppe Cosentino ◽  
...  
Keyword(s):  
Language Processing ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Right Hemisphere ◽  
Parietal Lobe ◽  
Brain Lesion ◽  
Direct Current Stimulation ◽  
Anodal Stimulation ◽  
Left And Right ◽  
The Right

Evidence derived from functional imaging and brain-lesion studies has shown a strong left lateralization for language, and a complementary right hemisphere dominance for visuospatial abilities. Nevertheless, the symmetrical functional division of the two hemispheres gives no reason for the complexity of the cognitive operations involved in carrying out a linguistic task. In fact, a growing number of neuroimaging and neurostimulation studies suggest a possible right hemisphere involvement in language processing. The objective of this work was to verify the contribution of the left and right parietal areas in a phonological task. We applied anodal transcranial direct current stimulation (tDCS) to the right or left inferior parietal lobe, during a syllabic reordering task. After having learnt a combination of images of real objects and trisyllabic pseudowords with a simple consonant–vowel (CV) syllabic structure (e.g., tu-ru-cu), participants were shown the same images paired to two different pseudowords: one correct but with transposed syllables, and one alternative, never before seen. The participant’s task was to orally produce the chosen pseudoword, after having rearranged the order of its syllables. Two types of error were considered: transposition (correct pseudoword but incorrectly reordered) and identity (incorrect pseudoword). The results showed that right anodal stimulation significantly reduced the number of transposition errors, whereas left anodal stimulation significantly reduced the number of identity errors. These results suggested that both left and right inferior parietal areas were differentially involved in a syllabic reordering task, and, crucially, they demonstrated that visuospatial processes served by the right inferior parietal area could be competent for establishing the correct syllabic order within a word.

The Impact of Transcranial Direct Current Stimulation on the Language Production of Healthy Adults and Individuals With Alzheimer's Disease

2016 ◽  
Vol 1 (2) ◽  
pp. 138-144
Author(s):  
Amy Vogel-Eyny ◽  
Elizabeth E. Galletta ◽  
Loraine K. Obler
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Language Production ◽  
Memory Systems ◽  
Brain Regions ◽  
Healthy Adults ◽  
Direct Current Stimulation ◽  
The Impact

Transcranial direct current stimulation (tDCS) is a non-invasive form of brain stimulation that is a technique for modulating cognitive and linguistic functions. Researchers employ tDCS as a way of examining the language system and related memory systems. Although the field is in its infancy, there is evidence to suggest that tDCS applied to language-related brain regions has the potential to exert a beneficial influence on the language and memory functioning of healthy adults as well as individuals with Alzheimer's disease (AD). The purpose of the present review is to critically evaluate the current body of literature on the impact of tDCS on language production in healthy adults and the related memory performance of individuals with AD.

scholarly journals Comparison of repeated transcranial stimulation and transcranial direct-current stimulation on primary motor cortex excitability and inhibition: A pilot study

2018 ◽  
pp. 59-67 ◽  
Author(s):  
Vincent Cabibel ◽  
Makii Muthalib ◽  
Jérôme Froger ◽  
Stéphane Perrey
Keyword(s):  
Pilot Study ◽  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
High Definition ◽  
Direct Current Stimulation ◽  
Motor Cortex Excitability ◽  
The Right

Repeated transcranial magnetic stimulation (rTMS) is a well-known clinical neuromodulation technique, but transcranial direct-current stimulation (tDCS) is rapidly growing interest for neurorehabilitation applications. Both methods (contralesional hemisphere inhibitory low-frequency: LF-rTMS or lesional hemisphere excitatory anodal: a-tDCS) have been employed to modify the interhemispheric imbalance following stroke. The aim of this pilot study was to compare aHD-tDCS (anodal high-definition tDCS) of the left M1 (2 mA, 20 min) and LF-rTMS of the right M1 (1 Hz, 20 min) to enhance excitability and reduce inhibition of the left primary motor cortex (M1) in five healthy subjects. Single-pulse TMS was used to elicit resting and active (low level muscle contraction, 5% of maximal electromyographic signal) motor-evoked potentials (MEPs) and cortical silent periods (CSPs) from the right and left extensor carpi radialis muscles at Baseline, immediately and 20 min (Post-Stim-20) after the end of each stimulation protocol. LF-rTMS or aHD-tDCS significantly increased right M1 resting and active MEP amplitude at Post-Stim-20 without any CSP modulation and with no difference between methods. In conclusion, this pilot study reported unexpected M1 excitability changes, which most likely stems from variability, which is a major concern in the field to consider.

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