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Heimann F, Weiss S, Müller HM. Anodal transcranial direct current stimulation (atDCS) and functional transcranial Doppler sonography (fTCD) in healthy elderly and patients with MCI: modulation of age-related changes in word fluency and language lateralization. FRONTIERS IN AGING 2024; 4:1171133. [PMID: 38414493 PMCID: PMC10896906 DOI: 10.3389/fragi.2023.1171133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 12/15/2023] [Indexed: 02/29/2024]
Abstract
Introduction: In addition to age-related changes in language, hemispheric lateralization of language functions steadily declines with age. Also, performance on word fluency tasks declines and is sensitive to the expression of dementia-related changes. The aim of this study is to evaluate the effect of anodal tDCS combined with a word fluency training on language lateralization and word fluency performance in healthy elderly subjects and in persons with mild cognitive impairment (MCI). Methods: The effect of anodal tDCS over the left inferio frontal gyrus (IFG) was measured in a group of healthy elderly up to the age of 67 years (YG, Ø = 63.9 ± 3.02), a group of healthy elderly aged 68 years and older (OG, Ø = 78.1, ± 4.85), and a group of patients with MCI (Ø = 81.18, ± 7.35) by comparing performance in phonological and semantic word fluency tasks before and after 3 days of tDCS. Half of the experimental participants received sham stimulation. In addition, language lateralization was determined using a lateralization index (LI) measured with functional transcranial Doppler sonography (fTCD) before and after the stimulation period. Results: Anodal tDCS was associated with significantly higher scores in phonological but not semantic word fluency in both YG and OG. In MCI patients, no difference was measured between the tDCS and sham groups in either word fluency task. fTCD showed significantly increased left lateralization in all three groups after the training phase. However, this effect was independent of tDCS and the degree of lateralization could not be predicted by word fluency performance in any of the groups. Discussion: Phonological word fluency can be increased with atDCS in healthy elderly people by stimulating the IFG in a 3-day training. When cognitive decline has reached a certain stage, as is the case with MCI, this paradigm does not seem to be effective enough.
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Affiliation(s)
- Florian Heimann
- Experimental Neurolinguistics Group, Bielefeld University, Bielefeld, Germany
| | - Sabine Weiss
- Experimental Neurolinguistics Group, Bielefeld University, Bielefeld, Germany
- Center for Cognitive Interaction Technology (CITEC), Bielefeld University, Bielefeld, Germany
- Clinical Linguistics, Bielefeld University, Bielefeld, Germany
| | - Horst M. Müller
- Experimental Neurolinguistics Group, Bielefeld University, Bielefeld, Germany
- Center for Cognitive Interaction Technology (CITEC), Bielefeld University, Bielefeld, Germany
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Balboa-Bandeira Y, Zubiaurre-Elorza L, García-Guerrero MA, Ibarretxe-Bilbao N, Ojeda N, Peña J. Effects of transcranial electrical stimulation techniques on foreign vocabulary learning. Behav Brain Res 2023; 438:114165. [PMID: 36270464 DOI: 10.1016/j.bbr.2022.114165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 09/12/2022] [Accepted: 10/15/2022] [Indexed: 11/05/2022]
Abstract
Although the use of transcranial electrical stimulation (tES) techniques on healthy population has been linked to facilitating language learning, studies on their effects on foreign language learning processes are scarce and results remain unclear. The objective of this study was to analyze whether tES enhances foreign language learning processes. Sixty-four healthy native Spanish-speaking participants were randomly assigned to four groups (transcranial direct current, transcranial random noise, tDCS-tRNS stimulation, or sham). They completed two intervention sessions with a two-week gap in between. During the first session the participants received stimulation (1.5 mA) while learning new English words and then performed recall and recognition tasks. Learning was assessed at follow-up, two weeks later. No differences in learning between groups were observed in the first session (F(1,61)= .86; p = .36). At follow-up, significantly higher learning accuracy was observed after tRNS compared to sham (p = .037). These results suggest that tRNS could be helpful in improving the processes involved in foreign language vocabulary learning.
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Affiliation(s)
- Yolanda Balboa-Bandeira
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Leire Zubiaurre-Elorza
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - M Acebo García-Guerrero
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Naroa Ibarretxe-Bilbao
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Natalia Ojeda
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Javier Peña
- Department of Methods and Experimental Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain.
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10-Hz tACS over the prefrontal cortex improves phonemic fluency in healthy individuals. Sci Rep 2022; 12:8305. [PMID: 35585105 PMCID: PMC9117193 DOI: 10.1038/s41598-022-11961-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 04/11/2022] [Indexed: 11/28/2022] Open
Abstract
Verbal fluency is an important indicator of human verbal ability. Methods to improve fluency is an interesting issue necessitating investigation. To do this, the current study required participants to randomly receive transcranial alternating current stimulation (tACS) at 10 Hz, 40 Hz (control frequency), and sham stimulation over the prefrontal cortex before a phonemic fluency task. It was found that 10-Hz tACS significantly improved phonemic fluency relative to sham stimulation. This result demonstrates the modulatory effect of 10-Hz tACS on language ability.
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Balboa-Bandeira Y, Zubiaurre-Elorza L, Ibarretxe-Bilbao N, Ojeda N, Peña J. Effects of transcranial electrical stimulation techniques on second and foreign language learning enhancement in healthy adults: A systematic review and meta-analysis. Neuropsychologia 2021; 160:107985. [PMID: 34371068 DOI: 10.1016/j.neuropsychologia.2021.107985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Transcranial electrical stimulation (tES) techniques have been used to enhance different cognitive domains such as language in healthy adults. While several reviews and meta-analysis have been conducted on the effects of tES on different language skills (picture naming, verbal fluency, word reading), there has been little research conducted to date on the effects of tES on the processes involved in foreign language learning. OBJECTIVE A meta-analysis was performed to quantify the effects of tES on foreign language learning processes (non-words, artificial grammar, and foreign languages), focusing on accuracy, response times and 1-week follow-up effects, if reported by the studies. RESULTS Eleven studies that had sham condition were reviewed. Nine of them were analyzed, including five using within-participant design, and four that employed between-participant design. The final analysis encompassed nine studies with 279 healthy participants. The analysis showed moderate enhancing effects of tES on overall language learning (g = 0.50, 95 % CI [0.29, 0.71], p = .0001). However, results were not significant on follow up data (g = 0.54, 95 % CI [-0.12, 1.20], p = .07), and on response times (g = 0.50, 95 % CI [-0.1, 1.18], p = .10). The effects were significantly moderated by years of education. CONCLUSIONS The results suggest that tES seems to enhance the mechanisms involved in foreign language learning; however, more research is needed to understand the impact scope of these techniques on language learning processes.
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Affiliation(s)
| | | | | | - Natalia Ojeda
- Department of Methods and Experimental Psychology, University of Deusto, Bilbao, Spain
| | - Javier Peña
- Department of Methods and Experimental Psychology, University of Deusto, Bilbao, Spain.
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Indahlastari A, Albizu A, Nissim NR, Traeger KR, O'Shea A, Woods AJ. Methods to monitor accurate and consistent electrode placements in conventional transcranial electrical stimulation. Brain Stimul 2019; 12:267-274. [PMID: 30420198 PMCID: PMC6348875 DOI: 10.1016/j.brs.2018.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Inaccurate electrode placement and electrode drift during a transcranial electrical stimulation (tES) session have been shown to alter predicted field distributions in the brain and thus may contribute to a large variation in tES study outcomes. Currently, there is no objective and independent measure to quantify electrode placement accuracy/drift in tES clinical studies. OBJECTIVE/HYPOTHESIS We proposed and tested novel methods to quantify accurate and consistent electrode placements in tES using models generated from a 3D scanner. METHODS Accurate electrode placements were quantified as Discrepancy in eight tES participants by comparing landmark distances of physical electrode locations F3/F4 to their model counterparts. Distances in models were computed using curve and linear based methods. Variability of landmark locations in a single subject was computed for multiple stimulation sessions to determine consistent electrode placements across four experimenters. MAIN RESULTS We obtained an average of 0.4 cm in Discrepancy, which was within the placement accuracy/drift threshold (1 cm) for conventional tES electrodes (∼35 cm2) to achieve reliable tES sessions suggested in the literature. Averaged Variability was 5.2%, with F4 electrode location as the least consistent placement. CONCLUSIONS These methods provide objective feedback for experimenters on their performance in placing tES electrodes. Applications of these methods can be used to monitor electrode locations in tES studies of a larger cohort using F3/F4 montage and other conventional electrode arrangements. Future studies may include co-registering the landmark locations with imaging-derived head models to quantify the effects of electrode accuracy/drift on predicted field distributions in the brain.
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Affiliation(s)
- Aprinda Indahlastari
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
| | - Alejandro Albizu
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Nicole R Nissim
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Kelsey R Traeger
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Andrew O'Shea
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Adam J Woods
- Department of Clinical and Health Psychology, Department of Neuroscience, Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
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Factors Contributing to the Failure to Replicate Findings of tDCS-Induced Enhancement of Verbal Fluency: A Response to Cattaneo et al (2016). Cogn Behav Neurol 2018; 31:23-25. [PMID: 29561316 DOI: 10.1097/wnn.0000000000000146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sung K, Gordon B. Transcranial direct current stimulation (tDCS) facilitates overall visual search response times but does not interact with visual search task factors. PLoS One 2018; 13:e0194640. [PMID: 29558513 PMCID: PMC5860774 DOI: 10.1371/journal.pone.0194640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 03/07/2018] [Indexed: 11/18/2022] Open
Abstract
Whether transcranial direct current stimulation (tDCS) affects mental functions, and how any such effects arise from its neural effects, continue to be debated. We investigated whether tDCS applied over the visual cortex (Oz) with a vertex (Cz) reference might affect response times (RTs) in a visual search task. We also examined whether any significant tDCS effects would interact with task factors (target presence, discrimination difficulty, and stimulus brightness) that are known to selectively influence one or the other of the two information processing stages posited by current models of visual search. Based on additive factor logic, we expected that the pattern of interactions involving a significant tDCS effect could help us colocalize the tDCS effect to one (or both) of the processing stages. In Experiment 1 (n = 12), anodal tDCS improved RTs significantly; cathodal tDCS produced a nonsignificant trend toward improvement. However, there were no interactions between the anodal tDCS effect and target presence or discrimination difficulty. In Experiment 2 (n = 18), we manipulated stimulus brightness along with target presence and discrimination difficulty. Anodal and cathodal tDCS both produced significant improvements in RTs. Again, the tDCS effects did not interact with any of the task factors. In Experiment 3 (n = 16), electrodes were placed at Cz and on the upper arm, to test for a possible effect of incidental stimulation of the motor regions under Cz. No effect of tDCS on RTs was found. These findings strengthen the case for tDCS having real effects on cerebral information processing. However, these effects did not clearly arise from either of the two processing stages of the visual search process. We suggest that this is because tDCS has a DIFFUSE, pervasive action across the task-relevant neuroanatomical region(s), not a discrete effect in terms of information processing stages.
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Affiliation(s)
- Kyongje Sung
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Barry Gordon
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Cognitive Science Department, The Johns Hopkins University, Baltimore, Maryland, United States of America
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Transcranial direct current stimulation (tDCS) modulation of picture naming and word reading: A meta-analysis of single session tDCS applied to healthy participants. Neuropsychologia 2017; 104:234-249. [DOI: 10.1016/j.neuropsychologia.2017.07.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/17/2017] [Accepted: 07/25/2017] [Indexed: 12/21/2022]
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Modulating phonemic fluency performance in healthy subjects with transcranial magnetic stimulation over the left or right lateral frontal cortex. Neuropsychologia 2017; 102:109-115. [DOI: 10.1016/j.neuropsychologia.2017.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 06/06/2017] [Accepted: 06/09/2017] [Indexed: 11/30/2022]
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Westwood SJ, Olson A, Miall RC, Nappo R, Romani C. Limits to tDCS effects in language: Failures to modulate word production in healthy participants with frontal or temporal tDCS. Cortex 2017; 86:64-82. [PMID: 27912107 PMCID: PMC5264390 DOI: 10.1016/j.cortex.2016.10.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/19/2016] [Accepted: 10/25/2016] [Indexed: 01/19/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well as possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms.
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Affiliation(s)
| | - Andrew Olson
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, UK
| | - R Chris Miall
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, UK
| | - Raffaele Nappo
- Aston University, Life & Health Sciences, Birmingham, UK
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