Kiminobu Furukawa, Harue Suzuki, Jun Fukuda
Faculty of Rehabilitation and Care, Seijoh University, 476-8588 Aichi, Japan. E-mail: furukawa@seijoh-u.ac.jp
DOI: 10.2340/16501977-1048

Objective: To observe the real-time muscle activity of bilateral hands while subjects draw circles under 2 conditions: with and without using Ramachandran’s mirror-box.
Subjects: A total of 24 healthy volunteers.
Methods: Subjects drew 4 circles sequentially using their dominant hand with the other hand at rest, both with and without looking at a mirror image. Circles were marked by 8 dots on the paper, which subjects connected up to draw the shape. The activity of the bilateral first dorsal interosseus muscles was recorded using surface electromyography.
Results: Muscle activity of the dominant hand remained constant during each task. In contrast, muscle activity of the non-dominant hand increased under the condition of watching the image in the mirror, but was low under the non-watching condition. Furthermore, muscle activity of the non-dominant hand increased over the duration of the task. However, wide variation between subjects was observed under the mirror-image condition.
Conclusion: Increased muscle action potential of the non-dominant hand may be induced by the circle drawing task of the dominant hand during Ramachandran’s mirror-box therapy, which supports previous observations of increased brain activity caused by watching a mirror image.