New research into how a patient compensates after losing a dominant hand might lead to new rehabilitation techniques for those recovering from stroke or amputation.
When use of a dominant hand is lost by amputation or stroke, a patient is forced to compensate by using the nondominant hand exclusively for precision tasks like writing or drawing. Presently, the behavioral and neurological effects of chronic, forced use of the nondominant hand largely are understudied and unknown.
A new study, conducted by investigators at the University of Missouri in Columbia, looked closely at changes in behaviors and brain function in amputees who lost their dominant hands.
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,” Scott Frey, PhD, professor of psychological sciences and director of the university’s Brain Imaging Center, said in a news release. “Our project analyzed the consequences of losing your dominant hand and how behaviors change for amputees. We also used functional magnetic resonance imaging to study brain function in people adapting to those situations.”
In the study, eight adult amputees who had been coping with the absence of their dominant right hands for an average 33 years performed simple drawing tests with their nondominant hands. A control group of right-handed adults also completed the same tests. The drawing tests were checked for speed and accuracy.
Frey and Benjamin Philip, PhD, a postdoctoral research fellow in the Department of Psychological Sciences, found individuals who were forced to compensate with their nondominant left hands performed precision tasks as well as the control group did with their dominant right hands.
The same tests were then repeated while brain function was observed using fMRI. Researchers found the brain areas formerly devoted to motor and sensory functions of the amputated hand actually contributed to compensation 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 in the release. “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,” Frey said in the release. “This compensatory reorganization raises the hope that, through targeted training, nondominant 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.”
Although more research is needed, the study’s findings might help develop rehab interventions for stroke patients who do not regain precision control of the dominant hand during acute and subacute phases of recovery. For some patients in the first seven to 18 months after a stroke, it may make sense to train the less affected nondominant side, researchers said.
Abstract:- http://www.jneurosci.org/content/34/10/3622
Ref.- TodayinPT
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