Brain Health

Popular Electric Brain Stim Actually Lowers IQ

Using a weak electric current in an attempt to boost brainpower or treat conditions has become popular among scientists and do-it-yourselfers, but a University of North Carolina School of Medicine study shows that using the most common form of electric brain stimulation had a statistically significant detrimental effect on IQ scores.

Published in the journal Behavioural Brain Research inMay 2015, the study adds to the increasing amount of literature showing that transcranial direct current stimulation – tDCS – has mixed results when it comes to cognitive enhancement.

A release from the univserity quotes senior author Flavio Frohlich, PhD, assistant professor of psychiatry, cell biology and physiology, biomedical engineering, and neurology, as saying, “It would be wonderful if we could use tDCS to enhance cognition because then we could potentially use it to treat cognitive impairment in psychiatric illnesses. So, this study is bad news. Yet, the finding makes sense. It means that some of the most sophisticated things the brain can do, in terms of cognition, can’t necessarily be altered with just a constant electric current.”

Frohlich, though, said that using less common alternating current stimulation – so-called tACS – could be a better approach, one that he has been investigating. Earlier this year, Frohlich’s lab found that tACS significantly boosted creativity, likely because he used it to target the brain’s natural electrical alpha oscillations, which have been implicated in creative thought.

With tDCS, scientists don’t target these brain waves, which represent neuronal patterns of communication throughout regions of the brain. Instead, they use tDCS to target brain structures, such particular regions of the cortex.

The tDCS boom started in 2000, when German scientists published a paper showing that tDCS could change the excitability of neurons in the motor cortex – the brain region that controls voluntary body movement. Since then, there’s been an explosion of tDCS studies to try to make neurons more active or less active and therefore change outcomes for a variety of brain functions, such as working memory and cognitive acuity, and for illnesses, such as depression and schizophrenia.

But Frohlich said that some of the studies that have made waves were poorly designed. Some studies were not properly double-blinded or properly placebo controlled. Other studies were very small – less than 10 people.

A recent meta-analysis of a large number of tDCS papers showed that tDCS is far from a magic pill for cognitive enhancement or brain-related health conditions.

“Aside from stimulating the motor cortex, which has very exciting implications for stroke rehabilitation, I think the jury is still out on tDCS,” said Frohlich, who is a member of the UNC Neuroscience Center.


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