Xuemei Huang and her colleagues of the Penn State Hershey College of Medicine are studying gait, or the manner in which people walk, to understand the physical signs that might be a very early marker for the onset of Parkinson's. They have confirmed Huang's clinical impression that in people with Parkinson's, the arm swing is asymmetrical. In other words, one arm swings much less than the other as a person walks.
"We know that Parkinson's patients lose their arm swing even very early in the disease but nobody had looked using a scientifically measured approach to see if the loss was asymmetrical or when this asymmetry first showed up," said Huang. "Our hypothesis is that because Parkinson's is an asymmetrical disease, the arm swing on one arm will be lost first compared to the other."
The researchers compared the arm swing of twelve people diagnosed three years earlier with Parkinson's, to eight people in a control group. The Parkinson's patients were asked to stop all medication the night before to avoid influencing the test results.
The team used special equipment to measure movement accurately, including many reflective markers on the study participants and eight digital cameras that captured the exact position of each segment of the body during a walk.
"Images from the cameras were sent to a computer where special software analysed the data" explained Huang. "When a person walks, the computer was able to calculate the degree of swing of each arm with millimeter accuracy."
Analysis of the magnitude of arm swing, asymmetry and walking speed revealed that the arm swing of people with Parkinson's has remarkably greater asymmetry than people in the control group – one arm swung significantly less than the other in the Parkinson's patients. When the participants walked at a faster speed, the arm swing increased but the corresponding asymmetry between them remained the same.
"Our data suggests that this could be a very useful tool for the early detection of Parkinson's," noted Huang. "There are wide scale efforts to find drugs that slow cell death. When they are found, they could be used in conjunction with this technique to arrest or perhaps cure the disease because they could be given before great damage has occurred."
MEDICA.de; Source: Pennsylvania State University