Electrical Brain Stimulation Improves Hand Motor Skills

Since its discovery many years ago, harnessing the power of electricity has been an ongoing endeavor. Benjamin Franklin’s eighteenth century experiments with electricity ushered in the evolution of the modern battery. In the middle of the last century, electricity was introduced as a remedy for difficult psychiatric disorders. “Shock treatment,” as it was known then, was used to treat many psychiatric diseases by inducing seizures. Now called electroconvulsive therapy (ECT), its mechanism of action is still unknown and its use is under strict guidelines set forth by the American Psychiatric Association. ECT is now reserved for severe psychiatric conditions when other treatments are deemed inadequate.

Fast forward to the 21st century, electricity is now being explored for its potential to improve neurological function. A recent study at Beth Israel Deaconess Hospital and Harvard Medical School suggests that electrical stimulation of the brain may improve dexterity. In this study, 16 right-handed volunteers were fitted with scalp electrodes and weak noninvasive direct currents were transmitted through their skulls to neurons in the motor cortex. Prior to, and after each stimulation, the participants were asked to perform finger-sequencing tasks on a standard keyboard with the non-dominant hand.

The results were amazing. With electrical stimulation of the motor cortex, significant improvements in motor function in the non-dominant hand were seen. Dual stimulation of the right and left motor cortex regions, resulted in improvement of scores by almost 25%. Stimulating only one motor region showed a smaller increase (16%).

The mechanism of action, like ECT, is not is not clear. However, it is believed that transcranial direct current stimulation (tDCS) increases neuron excitability and may provide an environment supportive for motor skills recovery. Although the physiology is unknown, the implications and possible applications of this procedure is profound. Stroke victims, and people suffering from other conditions where motor function is lost or reduced may be able to acquire new skills or recover some lost motor function.

Reference

Bradley W Vines, Carlo Cerruti, Gottfried Schlaug (2008). Dual-hemisphere tDCS facilitates greater improvements for healthy subjects’ non-dominant hand compared to uni-hemisphere stimulation. BMC Neuroscience, 9 (1) DOI: 10.1186/1471-2202-9-103