Stimulating the brain helps Alzheimer's patients remember again

Our brain has both short-term and long-term memory. While short-term memory helps us with things like remembering the bus number, long-term memory processes information for a long time. However, as we age, our memory does not work as well as it used to.

Electrical brain stimulation for 20 minutes on four consecutive days can improve two different types of memory in individuals 65 years and older for at least one month, a study published in the journal Nature Neuroscience reveals.

According to the study, this method could be beneficial for elderly people to maintain their errands very easily.

The research - conducted by a team of Boston University - used a group of 150 healthy volunteers aged between 65 to 88.

How did the study be carried out?

The authors delivered electrical currents through electrodes embedded in a cap worn by participants as they heard and immediately recalled five lists of 20 words.

They targeted two specific brain regions with two distinct stimulation frequencies. Targeting the inferior parietal lobule at a frequency of 4 Hz was found to improve recall of the words from the end of the list — indicative of storage in working memory — whereas targeting the dorsolateral prefrontal cortex at 60 Hz improved recall of words at the beginning — reflecting storage in long-term memory.

Participants with the lowest cognitive ability benefited most from brain stimulation, the study suggested.

This may be a cure for dementia and Alzheimer

As Financial Times reported, co-author Robert Reinhart believes that on-invasive neurostimulation is a potential treatment for memory loss in older people and particularly in those developing dementia.

“The work has obvious clinical implications,” he said. “The older people with poor general cognitive functioning coming into the experiment were the individuals who showed the largest improvements during both the intervention and the one-month point. [This] bodes well for transferring this [procedure] over to a proper clinical study in people with Alzheimer’s disease who are suffering from more severe memory impairments,” he said.

Reinhart said the Boston University team now intended to focus their work on “real-world” cognitive activities. “What we’re involved in now is relating our laboratory brain and behavioral measures to functional outcomes like . . . measures of activities of daily living,” he said. “[They] are more relevant for reducing the severe social and economic impact of impaired cognition that comes with age and mental illness.”

Abstract:

The development of technologies to protect or enhance memory in older people is an enduring goal of translational medicine. Here we describe repetitive (4-day) transcranial alternating current stimulation (tACS) protocols for the selective, sustainable enhancement of auditory–verbal working memory and long-term memory in 65–88-year-old people. Modulation of synchronous low-frequency, but not high-frequency, activity in parietal cortex preferentially improved working memory on day 3 and day 4 and 1 month after intervention, whereas modulation of synchronous high-frequency, but not low-frequency, activity in prefrontal cortex preferentially improved long-term memory on days 2–4 and 1 month after intervention. The rate of memory improvements over 4 days predicted the size of memory benefits 1 month later. Individuals with lower baseline cognitive function experienced larger, more enduring memory improvements. Our findings demonstrate that the plasticity of the aging brain can be selectively and sustainably exploited using repetitive and highly focalized neuromodulation grounded in spatiospectral parameters of memory-specific cortical circuitry.