Early Robotic Stroke Therapy Helps Reduce Physical Disability

A new study claims that using robots to help people recover motor function varies with the severity of a patient's disability at the time of rehabilitation: the less disability at the start of therapy, the more gain in physical ability.

Researchers at the Stroke Center at the University of California (Irvine, USA) studied 15 patients--average age 61--with partial paralysis on the right side of the body (the disabling strokes had occurred an average 2.6 years before therapy was initiated). The researchers then randomized seven patients to a robotic technique termed motor therapy, which consists of computer-aided grasping and releasing, alternating with rest. The remaining eight patients received a more complex robotic approach called premotor therapy, which requires grasping, releasing, and resting based on a timed visual cue, which involved more complex activity involving the premotor cortex, a higher level of the brain; only when the patient incompletely squeezed or relaxed their hand did the computer complete the movement for them. Physical recovery was measured with the Fugl-Meyer (F-M) 66-point score, the Action Research Arm Test, and the Box-and-Blocks Test. The researchers assessed patients after two weeks of therapy that included 24 hours of hand-wrist exercises and virtual-reality video game playing, and again one month later.

The results of the study showed that all patients had significant gains one month after treatment, averaging 2.1 points on the F-M scale and 1.2 points on the Action Research Arm Test, but not on the Box-and-Blocks test. Among all 15 patients, both forms of therapy produced similar gains. However, the six patients with higher baseline F-M scores (average 54) and less motor system damage showed significantly more gain with premotor than with motor therapy at one month. Nine patients with an average F-M score of 23 showed no difference in gains between these two therapies.

"The status of a patient's motor system at the beginning of therapy is very much related to how treatment will affect them,” said senior author Steven Cramer, M.D., an associate professor of neurology, anatomy, and neurobiology at UCI. "Robotic therapy may be useful in its own right, but it could also help rewire, or reshape, the brain in conjunction with other stroke therapies.”

The premotor cortex is an area of in the frontal lobe of the brain. It extends 3 mm in front of the primary motor cortex near the Sylvian fissure before narrowing to approximately 1 mm near the medial longitudinal fissure. It is responsible for sensory guidance of movement and control of proximal and trunk muscles of the body.

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