Beams of ultrasound could one day be used to combat Alzheimer's disease, scientists believe.
When tested on mice, the method cleared tangles of plaque in the brain - which have previously been linked to the degenerative disease - without appearing to damage tissue.
Researchers also discovered that the beams improved the animals’ memory.
High-energy ultrasound has previously been combined with injected microbubbles, which vibrate in response to sound waves, to pass drugs across the so-called blood brain barrier.
However, researchers who took part in the new study published in the journal 'Science Translational Medicine' have demonstrated for the first time that ultrasound alone could improve the debilitating condition.
“Our research was very exploratory and we really didn't expect to see such a massive effect,” Juergen Goetz of the University of Queensland in Brisbane, one of study authors, told Reuters. “I'm really excited by this.”
To make their findings researchers treated mice that had been genetically altered to produce amyloid plaques with ultrasound, and found the plaque was almost completely cleared in 75 percent of the animals.
Debate surrounds whether plaques are a cause or symptomatic of Alzheimer's, however the experiment found that treated mice had improved memory after completing three different tests in a maze.
The technique works by stimulating microglial cells, which form part of the brain's immune system, to engulf and absorb the plaques.
Goetz stressed that his research was at the very early stages and that human trials are still several years away, as further tests into long-term side effects are needed.
Researchers must also investigate how to use the technique on thicker skulls and larger brains – which will be tested using sheep.
Ultrasound devices capable of penetrating the human brain are already being tested for other conditions, with Israeli company InSightec pioneering it for tremors and chronic pain.
Dementia, of which Alzheimer's is the most common form, affects close to 50 million people worldwide and that number is set to reach 135 million by 2050, according to Alzheimer's Disease International, a non-profit campaign group.
A recent study published in The Lancet medical journal also provided hope for those fearful of the illness, showing that changes to lifestyle among the over-60s can slow mental decline.
Additional reporting by ReutersReuse content