Investigation of Factors Affecting Upper Extremity Function in Healthy Young Adults

The Turkish version of the Shoulder, Arm and Hand Problems Questionnaire (DASH-T) will be used to assess the functional level of the upper extremity [10]. The DASH-T questionnaire consists of 30 questions. The first 20 questions ask about physical ability and the last 10 questions ask about pain and related functional and environmental limitations. As the score approaches zero, the functional level of the person is high; as the score moves away from zero, the functional level of the person is low.

The grip strength of the participants will be performed with a hydraulic hand dynamometer on a chair with back and arm support. The participant will be asked to squeeze the dynamometer with maximum force. The measurement will be performed 3 times and the average value will be recorded.

Motor imagery will be assessed through a left/right judgment task in which participants will be required to recognize whether hand images correspond to their left or right side using the Recognise™ application (Neuro Orthopaedic Institute, Adelaide, Australia). For this test, participants will be seated comfortably in front of a table, with both elbows flexed at 90◦ and both index fingers placed at the bottom of the screen of an electronic tablet. Multiple images of forearms (20 on each side) in multiple postures, angles and skin colors will be randomly displayed in the center of the screen of the device. Participants will be given standard instructions to decide as quickly and accurately as possible whether each image is of the right or left hand by clicking on the 'left' (left fingers) or 'right' (right fingers) buttons displayed at the bottom of the screen.

Two-point discrimination will be assessed using a two-dot discriminator placed longitudinally and perpendicular to the index fingertip. The test score is the minimum distance at which the participant can discriminate between two dots in five consecutive trials. The assessment starts with a distance of 4 mm and is gradually reduced or increased depending on the participant's performance. A distance greater than 4 mm is considered impaired