People in their 70s suffering memory loss have had it restored after their brain was zapped with electric pulses.
It gave them the thinking power of someone in their 50s through just five 20 minute sessions, say scientists.
Known as Transcranial Magnetic Stimulation (TMS) it offers hope of combating Alzheimer’s disease.
It targets a specific area of grey matter called the hippocampus. Their memories improved by almost a third. The therapy is now to be tested on dementia patients.
Lead investigator Professor Joel Voss, of Northwestern University in Chicago, said:
“Older people’s memory got better up to the level we could no longer tell them apart from younger people. They got substantially better.”
The non-invasive therapy boosts nerve cells with currents passed through a large electromagnetic coil that is placed against the scalp.
It’s a complete alternative to drug therapy – which often has intolerable side-effects for many patients.
Formulated by scientists in Israel and the US it works by improving recall and reasoning.
The same device has been approved by the Food and Drug Administration (FDA) in the US for depression when other treatments are not successful.
The hippocampus is the memory control centre that degenerates in everyone as they age – explaining why the elderly become forgetful.
Prof Voss said: “It’s the part of the brain that links two unrelated things together into a memory – like the place you left your keys or your new neighbour’s name.
“Older adults often complain about having trouble with this.”
The study published in Neurology shows for the first time it’s possible to reverse the common problem safely – without any medications.
Prof Voss said: “There is no previous evidence the specific memory impairments and brain dysfunction seen in older adults can be rescued using brain stimulation or any other method.”
He added: “As we get older, our brains age too, and these changes mean our brain may not work as efficiently, so it is normal to experience some mild forgetfulness.
“With stimulation, we were able to essentially excite the areas of the brain that are involved in memory formation in older adults, improving their ability to recall items as well as younger adults.”
Using MRI (magnetic resonance imaging scans) his team located the hippocampus – which gets smaller over time – in 15 participants with an average age of 72.
They also identified another region called the parietal lobe that communicates with the hippocampus for delivery of the electrical currents.
This is behind and slightly above the left ear – but everyone had a slightly different spot.
It isn’t possible to directly stimulate the hippocampus – which creates, stores and retrieves memories – as it’s too deep inside for the magnetic fields to penetrate.
So the researchers chose a superficial target close to the surface of the skull – with high connectivity to the hippocampus.
All the 64 to 80 year old participants had normal age-related memory issues.
First author Aneesha Nilakantan, a neuroscience graduate student in Prof Voss’ lab, said: “We stimulated where brain activity is synchronised to the hippocampus, suggesting these regions talk to each other.”
At the start they were given memory tasks in which they learned arbitrary relations between paired objects on a computer screen.
They got less than 40 percent right – compared to another group of young adults with an average age of 25 who were correct about 55 percent of the time.
The researchers then applied high-frequency repetitive magnetic stimulation to the spot for five consecutive days for 20 minutes a day.
This increased the function of brain cells important for memory that are disrupted by ageing – evident by more neural activity visible on the scans.
Then, 24 hours after the final stimulation, they were given a fresh test in which they had to learn new arbitrary relations between paired items.
This time they scored at the same level of their young counterparts – showing their memories were now just as good.
The participants’ ability to recall memories improved 31 percent when compared to the beginning of the study.
The scans also showed more activity in the regions of the brain involved in memory formation.
Out of 84 questions on the memory test, participants answered an average of 33 questions correctly before stimulation. Afterwards, this rose by an average of 10.
Prof Voss said: “Memory improvements were highly consistent for participants after receiving stimulation, and participants were able to recall memories just as well as the group of young adults to whom they were compared at the start of the study, but the gains were temporary.”
When participants were tested again one week after the treatments ended, there were no differences between when they received the stimulation and when they received the sham treatment.
But the study also used a fake placebo stimulation condition which failed to improve memory – ensuring it was the TMS that was producing the results.
Prof Voss said: “Disruption and abnormal functioning of the hippocampal-cortical network, the region of the brain involved in memory formation, has been linked to age-related memory decline, so it’s exciting to see that by targeting this region, magnetic stimulation may help improve memory in older adults.
“These results may help us better understand how this network supports memory.”
The team now plan to test the treatment over longer periods on participants with mild cognitive impairment – the early stage of Alzheimer’s.
He said: “It’s important to note while our small study examined age-related memory loss, it did not examine this stimulation in people with memory loss from more serious conditions such as mild cognitive impairment or Alzheimer’s disease.”
Prof Voss isn’t certain how long the benefits could last. He suggests the enhanced memory could last longer with more stimulation.
For instance, when depression is treated with TMS for five weeks, those patients get an antidepressant effect that lasts for many months, he noted.
In a future study, Prof Voss will be stimulating the brain in persons with age-related memory loss for more weeks to test this.
Alzheimer’s disease and other forms of dementia affects 850,000 people in the UK – a figure set to rise to 2 million by 2050. There is no cure.