During motor training participants in the stimulation arm receive vibro-tactile feedback applied to their fingers when touching an object as measured by force-sensing resistors mounted to the fingertips.

The control group receives the same motor training with the same derives (force-sensing resistors, vibro-tactile stimulators) mounted to the hands but receives no stimulation.

Vibro-tactile stimulation will be administered to the fingers of the participants via C3 tactors (diameter: 2.03 cm, height: 0.64 cm, operating frequency: 180-320 Hz, see https://www.eaiinfo.com/tactor-info/). Vibro-tactile stimulation will be triggered by force-sensing resistors (TEA CAPTIV T-SENS FSR, see https://www.teaergo.com/products/tea-captiv-t-sens-fsr/).

The Action Research Arm Test (ARAT) is a 19 item observational measure to assess upper extremity performance (coordination, dexterity and functioning). Items comprising the ARAT are categorized into four subscales (grasp, grip, pinch and gross movement) and arranged in order of decreasing difficulty, with the most difficult task examined first, followed by the least difficult task. Task performance is rated on a 4-point scale, ranging from 0 (no movement) to 3 (movement performed normally). Scores may range from 0-57 points, with higher points indicating better performance.

A timed measure of fine manual dexterity where the patient is instructed to first take nine pegs out of a container and place them afterwards back into the empty holes of the container as quickly as possible.

The section motor function of upper limb is one of five domains, a three-point scale is used for rating performance as 0=cannot perform, 1=performs partially and 2=performs fully, max. possible score: 66 points.