May 24 (UPI) -- University of Missouri researchers have discovered how hand amputation and reattachment affect the brain and how those changes impact the patient.
"Previous research has found substantial reorganizational changes in the brain following limb injuries that decrease sensory and motor stimulation following limb injuries," Scott Frey, chair in Cognitive Neuroscience in the Departments of Psychological Sciences and Neurology at the University of Missouri-Columbia, said in a press release."These findings show that after surgical repairs, the effects of nerve injuries on the mature brain may continue even as former amputees recover varying degrees of sensory and motor functions in replanted or transplanted hands."
After a person loses a hand to amputation, nerves controlling sensation and movement are severed, which cause drastic changes in areas of the brain that controlled those functions.
The brain compensates for the loss by taking on other functions, but the study found that some of the changes continue even after the patient receives a hand transplant.
"When there is a sudden increase or decrease in stimulation that the brain receives, the function and structure of the brain begins to change," said Dr. Carmen M. Cirstea, research assistant professor of Physical Medicine and Rehabilitation at the University of Missouri-Columbia. "Using a noninvasive approach known as magnetic resonance spectroscopy [MRS] to examine areas of the brain previously involved with hand function, we observed the types of changes taking place at the neurochemical level after amputation, transplantation or reattachment."
Cirstea and her team used MRS to analyze the neuronal health and function of nerve cells of five current and former hand amputees and healthy subjects.
Study participants were asked to flex their fingers to activate sensorimotor areas in both sides of the brain, then researchers analyzed the levels of a chemical linked to neuronal health known as N-acetylaspartate, or NAA.
Researchers found that NAA values for the reattachment and transplant patients were similar to levels of amputees and much lower than in the control group.
The study was published in the Journal of Neurophysiology.