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A new study suggests that laser light therapy may improve short-term memory, which may have implications for treating ADHD. By Lorena/Stocksy
  • A new study shows that laser light therapy can improve short-term working memory in young adults.
  • The findings have future implications for treating health conditions that impact working memory, such as ADHD.
  • Despite the promising results, larger, more rigorous studies on diverse populations are still needed to determine the effectiveness of laser light therapy to improve cognition.

Whenever you need to remember the name of a person you just met, a set of instructions, or a shopping list, you rely on working memory.

This type of temporary memory is used for information needed in the present moment. It holds things that have not yet been committed to long-term memory.

Working memory is not just for recalling facts, though. It supports a number of day-to-day mental functions such as learning and problem-solving.

While most people have difficulty retaining information at times, especially when interrupted or distracted, certain health conditions can also impact working memory. This includes attention deficit hyperactivity disorder (ADHD), schizophrenia, and Alzheimer’s disease (AD).

To improve working memory, a new study suggests that it may be possible to offset some of these cognitive deficits by using laser light therapy.

The study was recently published in Science Advances.

Researchers at the University of Birmingham in the United Kingdom and Beijing Normal University in China found that laser light therapy improved working memory by around 10% in healthy volunteers.

The treatment, known as transcranial photobiomodulation (tPBM) delivers near-infrared to infrared light to the brain tissue through the scalp and skull.

Researchers are currently investigating tPBM as a way to improve cognitive function as well as to treat other conditions that affect the brain including:

“People with conditions like ADHD or other attention-related conditions could benefit from this type of treatment, which is safe, simple and non-invasive, with no side-effects,” study author Dongwei Li, a visiting PhD student in the University of Birmingham’s Centre for Human Brain Health, said in a news release.

The new studyincluded 90 male and female healthy volunteers ages 18 to 25 years old.

Researchers carried out several experiments in which participants were treated with laser light to the right prefrontal cortex, an area of the brain involved in working memory. The wavelength of light used was 1,064 nanometers (nm), in the near-infrared range.

Researchers also conducted other experiments using a shorter wavelength of light (852 nanometers, also near-infrared), and with laser light applied to the left prefrontal cortex.

Each participant was also treated with a sham, or inactive, stimulation to rule out the placebo effect. The active tPBM and sham sessions were done on separate days.

After 12 minutes of the tPBM or sham session, participants completed a working memory task, which involved remembering the orientation or color of a set of items displayed on the screen.

Researchers found that people who received the 1,064-nm tPBM treatment to the right prefrontal cortex performed about 10% better on the working memory task compared to their performance during the sham session.

Researchers also found that tPBM using 852-nm light had no effect on people’s performance on the working memory task. Neither did tPBM when applied to the left prefrontal cortex.

In addition, researchers used an electroencephalogram (EEG) to monitor the electrical activity of the brain during the sessions. The EEG showed changes in brain activity that predicted improvements in working memory performance.

Researchers are not certain why tPBM improved working memory, or how long the positive effects on working memory will last. More research, including rigorous studies with a longer follow-up on other age groups and populations, is needed to understand the effects.

Dr. Jason Huang, neurosurgeon and chairman of the Department of Neurosurgery at Baylor Scott & White Medical Center — Temple, TX, said that one of the unique aspects of the study is that the researchers ran four different experiments.

This includes comparing the 1,064-nm and 852-nm tPBM, “which has never been done before,” he told Healthline. “This alone contributes to the existing literature.”

Huang added that the study design seems to be “efficient” in spite of the small number of participants included. However, future research could benefit from including more participants.

Huang’s own research shows that tPBM can boost a number of cognitive abilities in people with mild to moderate dementia.

“We observed very notable improvement in attention, concentration and focus on tasks, and motor execution in our patients treated with active tPBM,” he said.

Unlike the new study, which treated only the prefrontal cortex, Huang’s study used a light treatment helmet device that illuminated more areas of the brain. In addition, treatments in his study were done twice a day for 8 weeks, compared to a single 12-minute session in the new study.

Although tPBM devices are commercially available, Huang said none of these are approved by the Food and Drug Administration (FDA), which limits their use in the clinic.

“Before recommending [this therapy] for use in treating patients clinically, more studies with a larger scope are needed in order to have additional evidence-based observations,” he said.

Recent studies estimate that up to 85% of children diagnosed with ADHD have some problem with their working memory.

“Those who do struggle with working memory tend to have more intense symptoms of inattention, impulsivity, and hyperactivity,” Dr. Nicole Mavrides, medical director of child and adolescent psychiatry at PM Pediatric Care Behavioral Health, told Healthline.

In addition, since working memory is needed for processing and storing information, Mavrides said children with a working memory deficit may have difficulty learning and memorizing things at school, learning to read, or performing math problems.

They may also have difficulty with multi-step instructions, she said, such as putting on their shoes, jacket and backpack.

The authors of the new study said because tPBM is safe, non-invasive, and cost-effective, it would be suitable as a way to boost working memory in people with ADHD.

However, additional research — including studies involving people with ADHD — is needed “before [tPBM] can be applied to improve cognition in healthy and clinical populations,” the authors said.

In the meantime, there are already ways for parents to help boost their child’s working memory, which can make it easier for a child to do the other cognitive tasks that rely on working memory.

“The best ways to target and improve working memory in kids with ADHD tend to be stimulant medications,” said Mavrides, “and practicing [and] training strategies — memory cards [and] games, letting your child teach you the material, active reading, etc.”

The cognitive benefits of laser light therapy are an area of ongoing research.

Scientists are particularly interested in how laser light therapy might positively affect the human brain and improve symptoms associated with ADHD, MDD, and Alzheimer’s, among others.

While people of all ages may experience short-term working memory deficits to some degree, these difficulties are especially pronounced in individuals experiencing neurocognitive issues.

If the findings from this new preliminary study prove to be effective, laser light therapy could eventually be used to improve working memory in people with conditions affecting the brain.

For now, if you have concerns about your own working memory or your child’s, you may wish to talk with your healthcare team about potential treatment options.