The largest and most comprehensive analysis of one quick, safe, non-invasive therapy has found it significantly enhances mental function. Best of all, this treatment works for all ages, in the cognitively healthy, and in those with mental health issues.
While this treatment is still in the early stages of development and needs further refinement before being used by the masses, brain experts believe it has great potential.
We’re talking about a treatment called transcranial alternating current stimulation.
Doctors have been zapping the brain with electrical currents since the 19th century. But the news has not always been good. In fact, the first known electrical stimulation in conscious humans in the year 1874 led to a catastrophic outcome.
The First Recorded Electrostimulation
That’s when scientist Roberts Bartholow inserted a pair of electrolytic needles into the brain of a young woman named Mary Rafferty. He experimented with applying a small electric current to different sections of her brain and was able to stimulate movement in corresponding parts of her body.
When Mr. Bartholow increased the level of current, she became distressed and experienced convulsions, eventually falling into a coma. Three days later, she had a seizure and died. While this experiment certainly sounds barbaric, and rest assured, history is divided over Roberts Bartholow’s experiments, that’s not the state of things in modern medicine.
Today, doctors are able to safely apply electrical stimulation to the brain. What’s more, interest in the brain health benefits of electrical brain stimulation has grown over recent years.
Transcranial Alternating Current Stimulation
One form of electrical brain stimulation is called transcranial alternating current stimulation (tACS). In this procedure weak currents oscillating at specific frequencies are applied to targeted areas of the brain through electrodes placed on the scalp, usually for a period of 20 minutes a day over several days.
The idea is to correct abnormalities in the rhythmic firing of brain cells in people with various mental health conditions. Helping the cells return to normal rhythmic firing is said to promote healthy brain function, because brain cells only communicate effectively when their rhythm is coordinated.
After brain cell firing is normalized, improvements in cognitive function are maintained for at least 30 days.
In fact, a review of 51 experiments in human volunteers conducted in 2016 found promising evidence that tACS can reliably improve cognitive performance even in healthy adults.
Since then, the number of studies has doubled, so it was time for another review.
Helps Everything from ADHD to Mild Cognitive Impairment
The new review included 102 studies containing 2,893 adults.
Since the procedure can be used in many ways, the studies were vastly different in terms of which areas of the brain were targeted, how the electrodes were arranged on the scalp, the frequency and intensity of the current, the cognitive tasks participants were given, and their ages, which spanned from young adults to the elderly.
Health status also varied widely.
Among the whole cohort, about six percent were diagnosed with mental conditions including clinical depression, ADHD, epilepsy, Parkinson’s, schizophrenia, and mild cognitive impairment.
Although such a review provides a good overview of the treatment, it’s difficult to draw a definitive conclusion regarding the therapy because of the large differences in study designs.
Even so, from all the studies researchers extracted a total of 304 measures of mental function and the results were very encouraging.
Mental Function Improves Across The Board
Overall, the trials showed modest to moderate improvements that were immediate and consistent.
Researchers saw the strongest gains in executive function – a range of abilities that include mental flexibility, problem solving, and planning. They also saw improvements in the ability to pay attention, to memorize information over short and longer periods of time, and in measures of intelligence.
Interestingly, researchers found enhancements in cognitive function were generally stronger after the treatment had finished rather than during the treatment itself.
The analysis also looked separately at older adults who are more vulnerable to cognitive changes and people with neuropsychiatric conditions. In both populations, the team observed reliable evidence for improvements in cognitive function.
Calming Down an Overexcited Brain
The review also included a specialized form of tACS that targets two brain regions simultaneously. This bidirectional application can be manipulated to enhance or reduce mental function.
Changing mental function in either direction would be useful in conditions where the brain needs to be either stimulated or dampened down from overexcitement.
Shrey Grover, first author of the new study published in the journal Science Translational Medicine in May explained, saying, “Developments in the field of tACS are bringing researchers closer to being able to safely enhance mental function in a noninvasive way that doesn’t require medication.”
While he described the treatment as “promising”, he added that “we’re still some years away from having it widely available.”
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