Multiple exposure image with sunrise and sea inside woman silhouette. Psychology concept

This story is part of a series on the current progression in Regenerative Medicine. This piece discusses advances in brain stimulation therapies.

In 1999, I defined regenerative medicine as the collection of interventions that restore normal function to tissues and organs damaged by disease, injured by trauma, or worn by time. I include a full spectrum of chemical, gene, and protein-based medicines, cell-based therapies, and biomechanical interventions that achieve that goal.

New electronic brain stimulation therapies may be the first step to finding a long-awaited cure for Alzheimer’s Disease. In General Psychiatry, Dr. Xingxing Li and colleagues from Ningbo University in China describe a form of transcranial stimulation that improves the cognitive function of Alzheimer’s patients. While only a symptom treatment and not a cure or prophylaxis for the disease, there are signs that brain stimulation could be an avenue for an Alzheimer’s cure in the near future.

Alzheimer’s is among the most common and difficult diseases. In the United States alone, over six million Americans live with Alzheimer’s, and many more are at risk. One in three seniors dies of Alzheimer’s or another degenerative dementia, more than breast and prostate cancer combined.

Despite Alzheimer’s research at the National Institute of Health reaching more than $3.7 billion annually, a cure is still unavailable.

As we age, our neural connections naturally slow, resulting in minor reductions in memory and cognition. With Alzheimer’s, this degeneration is accelerated significantly, resulting in severe memory loss, confusion, cognitive decline, and motor complications.

In their study, Li and colleagues targeted the degenerating neurons with transcranial direct current stimulation. Simply put, the researchers passed low-amperage electronic currents through the brain—a more elegant and measured approach to electroshock therapy of decades past.

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FIGURE 1: Schematic representation of transcranial direct current stimulation treatment.

Recent studies have shown that consistent transcranial direct current stimulation treatment can result in reduced symptom severity for a range of conditions, including stroke, brain injury, depression, schizophrenia, and motor dysfunction.

To test the potential benefit of this treatment in an Alzheimer’s context, Li and colleagues treated a cohort of 140 patients with mild to moderate Alzheimer’s twice daily with transcranial direct current stimulation for up to six weeks.

The researchers used word recall tests to test changes in patient cognition, asking patients to remember words or phrases to which they had been previously exposed. Their recollection was then quantified by a score representing short-term memory cognition. 

Over the six week treatment period, the researchers found that daily transcranial direct current stimulation sessions significantly improved cognitive and memory function in patients with mild to moderate Alzheimer’s compared to the control.

While week two results showed little effect as compared to the initial scores, over the following four weeks, cognition scores improved drastically as compared to the control group.

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FIGURE 2: Enhanced cognitive and plasticity induced by transcranial direct current stimulation in patients with Alzheimer’s.

Li and colleagues caveat that memory cognition is one of the more complicated processes in neural function, and there may be a number of factors at play that increase word recall scores. However, the increase is statistically significant and warrants further investigation.

The researchers also found that transcranial direct current stimulation treatments improved patient neuroplasticity. This is the brain’s ability to form new neural connections based on adaptation to one’s environment and lifestyle. Neuroplasticity is often hindered in Alzheimer’s patients. Improved neuroplasticity post-treatment indicates not only mitigation of Alzheimer’s symptoms but improvement of the condition overall.

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FIGURE 3: Transcranial direct current stimulation enhances cortical plasticity, and enhanced plasticity is associated with cognitive improvement. 

There are some side effects noted from transcranial direct current stimulation treatment, most notably headaches, fatigue, and discomfort, but nothing damaging or life-threatening, and these conditions are usually found during or immediately following treatment, wearing off over time.

I also note that the researchers do not follow up with their cohort over a longer period. Whether transcranial direct current stimulation treatment enables continued progress even after the treatments cease is a major factor in the long-term viability of the therapy.

This is far from the first nerve stimulation method described in this series. For instance, recent studies have found that vagus nerve stimulation could improve chronic inflammation, resulting in a cascade of positive health outcomes.

While transcranial direct current stimulation treatment is still somewhat mysterious in the exact interactions by which electronic stimulation promotes neural plasticity and cognitive improvement, it is clear that there is a statistically significant correlation between the treatment and health improvement for Alzheimer’s patients.

I highly encourage the ongoing research and development of this treatment avenue and those similar and anticipate how such treatments could be used to benefit those suffering from this terrible disease in the years to come.

To read more of this series, please visit