Research appearing in the journal Restorative Neurology and Neuroscience suggests that adaptive changes occur in an amputee’s brain following the implantation of multielectrode arrays inside peripheral nerves. Camillo Porcaro, PhD, lead investigator, Institute of Neuroscience, Newcastle University, Medical School, Newcastle upon Tyne, UK, and the Institute of Cognitive Sciences and Technologies (ISTC) – National Research Council (CNR), explains the researchers’ findings, which encompassed a male aged 26 years old with a left arm amputation. 

“We found that a neurally-interfaced hand prosthesis re-established communication between the central and peripheral nervous systems, not only restructuring the areas directly responsible for motor control but also their function balance within the bi-hemispheric system necessary for motor control,” Porcaro says.

During the study, four microelectrode arrays were implanted in the ulnar and median nerves in the patient’s amputation site and remained there for a 4-week period. A recent news release notes that prior to implantation, the patient was trained for 2 weeks via video instruction to perform three specific movements with his phantom hand. Researchers report that during the experimental period, the patient underwent training to control a hand prosthesis using the implanted microelectrodes to perform the same hand grip tasks. 

A blend of the hand grip tasks and visual feedback from the prosthesis allowed the patient to receive sensory feedback from an experimenter, which in turn delivered electrical pulses to the nerves activated by each movement, the release notes. Researchers add that EEG signals were also recorded as the patient moved his right hand and the prosthesis. The results suggest that the right hand exhibited activation of the primary sensory and motor areas for its movement, on the left side of the brain. 

Prior to implantation, researchers say, commands to move the phantom left hand triggered the activation of primary sensory and motor areas on the left side of the brain, as well as the pre-motor and supplementary motor cortices on both sides of the brain. According to the release, following 4 weeks of prosthesis motor control training with implanted microelectrodes, cerebral activation changed significantly. 

Procaro concludes that the results of the study, “confirm that neural interfaces are optimal candidates for hand prosthesis control. They establish communication channels needed for natural control of the prosthesis. Furthermore, neural interfaces recreate the connection with the environment that promotes neuroplasticity. Bi-hemispheric networks regain the physiological communication necessary for motor control,” Procaro says.

Source: IOS Press