From an Italian team, a neurotechnology that interprets movement intentions to restore finger dexterity.
Brushing your teeth, sending a message from your mobile phone, holding someone’s hand: usual movements, but impossible if we didn’t have hands that are a true masterpiece of engineering, strong but also precise thanks to the coordinated movements of 34 muscles and 27 bones. Losing the mobility of the hand, due to a stroke or spinal cord injury, means being less independent and one way to recover it may be the electrical stimulation of the neuromuscular system, which restores the motor command that must reach the muscle from the nerve.
To control the finest movements, in theory, one would have to implant as many electrodes as there are muscles in the hand, a very complex operation. On the other hand, using a single electrode in the spinal cord can stimulate multiple muscles at the same time, but the dexterity and precision of a single finger is lost.
How to overcome this obstacle? The solution could come from an innovative neurotechnology developed in Italy. The Regrasp project, led by Elena Losanno and Silvestro Micera of the Scuola Superiore Sant’Anna in Pisa, aims at targeted nerve stimulation. The system uses a stimulator connected to a few electrodes implanted in the peripheral nerves of the patient’s arm. Added to these are external wireless sensors which, by communicating with a portable controller (similar to a smartwatch), “understand” the patient’s intention to move and activate the stimulator at the right time. In this way, with a minimum number of electrodes, good dexterity can be restored, being able to move the fingers individually to button a shirt, use a cell phone, lift a cup.
How the bionic hand works
(The article continues below the infographic)
Brain Live
But to “repair” the movement it is also essential to understand in detail how the brain controls it. This is precisely the goal of other cutting-edge research. These are conducted, for example, in the laboratory led by Patrizia Fattori, neuroscientist at the University of Bologna and coordinator of the sub-project (Spoke 4) dedicated to the interactions between the brain and the body.
His team uses a portable, non-invasive neuroimaging technique (fNIRS), which uses infrared spectroscopy to measure changes in cerebral blood oxygenation and then examine brain activity in real time. «We are observing how the activity of the cerebral cortex changes in real and virtual contexts, while moving or interacting with others», says Fattori. “We have identified a specific communication pathway between neurons,” he explains. «It is located in an area of the cortex that integrates sensory and motor information.
When this pathway deteriorates, difficulties arise in perceiving movement, reaching objects or orienting oneself in space: typical problems of diseases such as Parkinson’s. Use this method neuroimaging to evaluate the impairment of this pathway could allow for more timely diagnoses and more targeted interventions.”
