Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation
Background Transcranial direct current stimulation (tDCS) is a popular non-invasive brain stimulation technique that has been shown to influence cortical excitability. While polarity specific effects have often been reported, this is not always the case, and variability in both the magnitude and...
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| Format: | Article |
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Elsevier
2016
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| Online Access: | https://eprints.nottingham.ac.uk/34423/ |
| _version_ | 1848794850092122112 |
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| author | Dyke, Katherine Kim, Soyoung Jackson, Georgina M. Jackson, Stephen R. |
| author_facet | Dyke, Katherine Kim, Soyoung Jackson, Georgina M. Jackson, Stephen R. |
| author_sort | Dyke, Katherine |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Background
Transcranial direct current stimulation (tDCS) is a popular non-invasive brain stimulation technique that has been shown to influence cortical excitability. While polarity specific effects have often been reported, this is not always the case, and variability in both the magnitude and direction of the effects have been observed.
Objective/ hypothesis
We aimed to explore the consistency and reliability of the effects of tDCS by investigating changes in cortical excitability across multiple testing sessions in the same individuals. A within subjects design was used to investigate the effects of anodal and cathodal tDCS applied to the motor cortex. Four experimental sessions were tested for each polarity in addition to two sham sessions.
Methods
Transcranial Magnetic Stimulation (TMS) was used to measure cortical excitability (TMS recruitment curves). Changes in excitability were measured by comparing baseline measures and those taken immediately following 20minutes of 2mA stimulation or sham stimulation.
Results
Anodal tDCS significantly increased cortical excitability at a group level, whereas cathodal tDCS failed to have any significant effects. The sham condition also failed to show any significant changes. Analysis of intra-subject responses to anodal stimulation across four sessions suggest that the amount of change in excitability across sessions was only weakly associated, and was found to have poor reliability across sessions (ICC=0.276). The effects of cathodal stimulation show even poorer reliability across sessions (ICC=0.137). In contrast ICC analysis for the two sessions of sham stimulation reflect a moderate level of reliability (ICC=.424).
Conclusions
Our findings indicate that although 2mA anodal tDCS is effective at increasing cortical excitability at group level, the effects are unreliable across repeated testing sessions within individual participants. Our results suggest that 2mA cathodal tDCS does not significantly alter cortical excitability immediately following stimulation and that there is poor reliability of the effect within the same individual across different testing sessions. |
| first_indexed | 2025-11-14T19:22:44Z |
| format | Article |
| id | nottingham-34423 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:22:44Z |
| publishDate | 2016 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-344232020-05-04T18:19:20Z https://eprints.nottingham.ac.uk/34423/ Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation Dyke, Katherine Kim, Soyoung Jackson, Georgina M. Jackson, Stephen R. Background Transcranial direct current stimulation (tDCS) is a popular non-invasive brain stimulation technique that has been shown to influence cortical excitability. While polarity specific effects have often been reported, this is not always the case, and variability in both the magnitude and direction of the effects have been observed. Objective/ hypothesis We aimed to explore the consistency and reliability of the effects of tDCS by investigating changes in cortical excitability across multiple testing sessions in the same individuals. A within subjects design was used to investigate the effects of anodal and cathodal tDCS applied to the motor cortex. Four experimental sessions were tested for each polarity in addition to two sham sessions. Methods Transcranial Magnetic Stimulation (TMS) was used to measure cortical excitability (TMS recruitment curves). Changes in excitability were measured by comparing baseline measures and those taken immediately following 20minutes of 2mA stimulation or sham stimulation. Results Anodal tDCS significantly increased cortical excitability at a group level, whereas cathodal tDCS failed to have any significant effects. The sham condition also failed to show any significant changes. Analysis of intra-subject responses to anodal stimulation across four sessions suggest that the amount of change in excitability across sessions was only weakly associated, and was found to have poor reliability across sessions (ICC=0.276). The effects of cathodal stimulation show even poorer reliability across sessions (ICC=0.137). In contrast ICC analysis for the two sessions of sham stimulation reflect a moderate level of reliability (ICC=.424). Conclusions Our findings indicate that although 2mA anodal tDCS is effective at increasing cortical excitability at group level, the effects are unreliable across repeated testing sessions within individual participants. Our results suggest that 2mA cathodal tDCS does not significantly alter cortical excitability immediately following stimulation and that there is poor reliability of the effect within the same individual across different testing sessions. Elsevier 2016-11-30 Article PeerReviewed Dyke, Katherine, Kim, Soyoung, Jackson, Georgina M. and Jackson, Stephen R. (2016) Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation. Brain Stimulation, 9 (6). pp. 819-825. ISSN 1876-4754 Transcranial Direct Current Stimulation (tDCS); Transcranial Magnetic Stimulation (TMS); Motor Cortex; Cortical Excitability http://dx.doi.org/10.1016/j.brs.2016.06.052 doi:10.1016/j.brs.2016.06.052 doi:10.1016/j.brs.2016.06.052 |
| spellingShingle | Transcranial Direct Current Stimulation (tDCS); Transcranial Magnetic Stimulation (TMS); Motor Cortex; Cortical Excitability Dyke, Katherine Kim, Soyoung Jackson, Georgina M. Jackson, Stephen R. Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title | Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title_full | Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title_fullStr | Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title_full_unstemmed | Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title_short | Intra-subject consistency and reliability of response following 2mA transcranial direct current stimulation |
| title_sort | intra-subject consistency and reliability of response following 2ma transcranial direct current stimulation |
| topic | Transcranial Direct Current Stimulation (tDCS); Transcranial Magnetic Stimulation (TMS); Motor Cortex; Cortical Excitability |
| url | https://eprints.nottingham.ac.uk/34423/ https://eprints.nottingham.ac.uk/34423/ https://eprints.nottingham.ac.uk/34423/ |