COLUMBIA, MO — University of Missouri researchers have determined how amputees compensate when losing a dominant hand, which could lead to better rehabilitation techniques for those suffering from amputation or stroke.
The study was funded by the DoD.1
“Half of the work in our lab focuses on amputees, particularly upper-limb amputees, who are out of the acute phase of their recoveries; the other half involves those who have suffered the loss of function due to stroke or neurological disorders,” said Scott Frey, PhD, professor of psychological sciences and director of the Brain Imaging Center at the university. “Our project analyzed the consequences of losing your dominant hand and how behaviors change for amputees. We also used functional magnetic resonance imaging (fMRI) to study brain function in people adapting to those situations. Our hope is that, by studying how amputees cope in these circumstances, we can help improve rehabilitation methods and quality of life in patients facing this loss.”
For the study, speed and accuracy was checked for amputees forced to use their nondominant hands for simple drawing tests. Interestingly, the test group actually performed precision tasks as well as the control group did with their dominant right hands.
The same evaluations then were performed with functional magnetic resonance imaging (fMRI), and the brain was observed. The areas previously devoted to motor and sensory functions of the amputated hand actually was contributing to help compensate for the loss on the nondominant side.
“Most people know that the left side of your brain controls the right hand and vice versa,” Frey said. “For example, if you’re right-handed and you’re writing or drawing, the left sensory and motor areas show increased activity. We found that when amputees were forced to use their nondominant hands for years or decades, they exhibited performance-related increases in both the right and left hemispheres. In other words, their ability to compensate with the left hand appears to involve exploiting brain mechanisms that previously were devoted to controlling their now absent dominant hands.
“This compensatory reorganization raises the hope that, through targeted training, non-dominant hand functions can be vastly improved, enabling a better quality of life for those who have lost dominant hand functions due to bodily or brain injury or disease.”
1Philip BA, Frey SH. Compensatory changes accompanying chronic forced use of the nondominant hand by unilateral amputees. J Neurosci. 2014 Mar 5;34(10):3622-31. doi: 10.1523/JNEUROSCI.3770-13.2014. PubMed PMID: 24599461; PubMed Central PMCID: PMC3942579.