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Simultaneous EEG Monitoring During Transcranial Direct Current Stimulation
Published on: June 17, 2013
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Expectations may influence the effects of transcranial direct current stimulation
Sheida Rabipour1, Allan D Wu2, Patrick S R Davidson3
1School of Psychology, University of Ottawa, Ottawa, ON, Canada.
Neuropsychologia
|September 19, 2018
Summary
Expectations significantly influence transcranial direct current stimulation (tDCS) outcomes. High expectations enhance cognitive improvements, while low expectations may reduce effectiveness, highlighting the need to consider psychological factors in tDCS research.
Area of Science:
- Neuroscience
- Cognitive Psychology
Background:
- Transcranial direct current stimulation (tDCS) is a promising, low-cost neuromodulation technique for cognitive enhancement and mood improvement.
- Psychological factors, particularly outcome expectations, are understudied in tDCS research despite their potential to mediate placebo-like effects and influence intervention responsiveness.
Purpose of the Study:
- To investigate the impact of expectation priming on cognitive performance and subjective experience during tDCS.
- To determine if pre-existing beliefs or manipulated expectations affect outcomes in a working memory task.
Main Methods:
- 88 healthy young adults underwent sham-controlled anodal tDCS over the left dorsolateral prefrontal cortex during working memory training.
- Expectations were assessed at baseline and after receiving either high or low effectiveness priming.
- Cognitive performance (working memory, verbal fluency) and subjective experience were measured.
Main Results:
- Expectation priming significantly altered participants' beliefs about tDCS effectiveness.
- Greater working memory improvement was observed in participants primed with high expectations compared to low expectations.
- Active tDCS combined with low expectation priming resulted in the poorest performance, suggesting an interaction effect.
- High expectation priming was associated with a more pleasant overall experience and greater satisfaction.
Conclusions:
- Participant expectations are a critical factor influencing tDCS outcomes and should be controlled for in research and clinical applications.
- Neuromodulation effectiveness may be modulated by psychological context, including expectancy effects.
- Future tDCS studies should incorporate measures of expectation to better understand individual variability in response.
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