Robotic arm can improve motor control after stroke

A computerized robotic arm trainer appears to be more effective than electrical stimulation in improving motor control and strength in stroke patients who are left with severe arm paralysis, German investigators report.

The effectiveness of the Bi-Manu-Track robotic arm trainer (Reha-Stim Company, Berlin), which helps the arm muscles to contract and flex, was compared with electric stimulation, which applies electrical pulses to the affected limb.

Dr. Stefan Hesse, from Klinic Berlin, and associates recruited patients 4 to 8 weeks after stroke causing severe arm paralysis. Twenty-one patients were randomly assigned to the arm trainer group and 22 to electrical stimulation group. In addition to regular physical therapy, all of the patients received 20 minutes of the intervention therapy every work day for 6 weeks, according to the report in the medical journal Stroke. Patients in the arm trainer group performed 800 repetitions per session, while those in the electrical stimulation group performed 60 to 80 wrist extensions per session. At the end of the 6-week trial, the average motor function score was 24.6 in the arm trainer group and 10.4 in the electrical stimulation group. After 3 months, those in the arm trainer group still had higher motor scores (30.0 versus 16.6).

Average scores for upper limb muscle strength were also higher in the arm trainer group — 21.8 versus 6.8, respectively, at week 6, and 22.6 versus 6.9 at week 18. Muscle tone did not differ between groups. The greater improvement achieved with the arm trainer “is probably attributable to the greater number of repetitions and the bilateral approach,” Hesse’s group concludes. reuters