Elderly subjects temporarily improved their working memory through non-invasive brain stimulation. An effect to confirm over time.
Will it be possible tomorrow to use non-invasive brain stimulation techniques to reduce or even dissipate age-related memory loss? This is the hope raised by the results of two US pilot studies. In elderly subjects (from age 64 to age 80 in the first study, from age 60 to age 76 in the second), these transcranial magnetic or electrical stimulation methods succeeded in restoring memory performances comparable to those of younger subjects. Results judged "Very encouraging" by Anne Sauvaget, psychiatrist, head of the neuromodulation unit in psychiatry at Nantes University Hospital. "Especially since these non-invasive methods are well tolerated. "
With age, it is especially the "working memory" which is weakening, that which records in the short term the recent information (the place where we parked, the wire of a speech …). "Almost everyone experiences a decline in memory performance with age"notes Joel Voss, associate professor at Northwestern University in Chicago, who coordinated the study published April 17 in the journal Neurology.
Aim at the seahorse
This study explored the impact of repeated transcranial magnetic stimulation (rTMS). Developed since 1985, the rTMS consists in applying a magnetized coil against a precise point of the skull. The goal: modulate the activity of neurons in specific regions of the brain. The technique was first used in neurology to treat abnormal movements or chronic pain. For twenty years, this method has also been applied to the treatment of depressions or hallucinations in schizophrenia.
Here, rTMS was evaluated in 15 subjects aged 64 to 80 years. For five days in a row, each of them received a twenty-minute daily session of TMS. The target structure: the hippocampus, a deep brain structure that atrophies with age, and plays a central role in the working memory. Problem: the hippocampus is buried in the brain. It is therefore not directly accessible to the magnetic field. "The rTMS does not penetrate more than 1.5 to 2 centimeters from the surface of the brain"explains Professor Emmanuel Haffen, head of the Adult Psychiatry Department at the University Hospital of Besançon. So it had to be tricky. "We have targeted a surface region whose activity is synchronized with that of the hippocampus, suggesting that these two regions communicate"says Aneesa Nilakantan, the first author of this work. This region is a "spot" located in the parietal lobe, at the back and a little above the left ear.