## 2 Materials and Methods
### Device's Mechanism and Built  
The developed exoskeleton robotic device consists of the proximal and distal part. The device's linkage mechanism represents the distal part. It includes the mounting brackets, where the actuators are attached, seven parallel segments on each side--laterally and medially--and the proximal and distal finger rests that connect both sides of the segments. The segments on each side are connected in a parallel and successive manner, allowing the linkage to move from the bottom, flexed position into the top, extended position by actively rotating just one segment. Figure 1 shows a lateral (A) and medial (B) view of the mechanism, depicting the successive connection of the segments. The numbers in Figure 1 correspond to the following parts--the mounting bracket (1), actuator (2), upper (3), middle (4), lower (5), central (6), triangular (7), oval (8), and the end (9) segment. The dimensions and connections between the segments determine the mechanism's movement, which, in turn, determines the movement of the wrist and fingers. The movement in the wrist is more dependent on the dimensions of the upper (3), middle (4), and partially the central (6) segment. By contrast, the movement of the fingers depends more on the dimensions of the oval (8), end (9), and lower (5) segment. The lower segment (5) is the only actively driven segment. The proximal (11) and distal (12) finger rest connect the lateral and medial portion of the segments--they are marked, along with the forearm support (10), in Figure 2. The proximal finger rest (11) is installed between the central (6) segments, and the distal finger rest (12) is installed between the end (9) segments. The proximal finger rest (11) supports the metacarpophalangeal (MCP) joints, and the distal finger rest (12) supports the fingers beyond their proximal interphalangeal (PIP) joints. The PIP joints are not supported. The thumb is secured at the bottom of the proximal finger rest (12) inside  
Figure 1: Sketch of the device’s mechanism, lateral (**A**) and medial (**B**) view. The numbers in the figures correspond to the following parts—1: mounting bracket, 2: actuator, 3: upper segment, 4: middle segment, 5: lower segment, 6: central segment, 7: triangular segment, 8: oval segment, and 9: end segment. which allows for the position of the thumb to be adjusted laterally or medially. The fingers are individually fastened on the distal finger rest (12) with an elastic band, which runs through the openings in the finger rest--this allows the fingers to slide slightly back and forth along the finger rests while moving from flexion to extension. Distal finger rests of different dimensions can help adjust the distance between the proximal (11) and distal (12) finger rest, thus making the device adaptable to different lengths of patients' fingers, as well as to the use with the left or right hand. The mounting brackets (1) with actuators (2) connect the distal part of the device with its proximal part. The latter consists of an aluminium base--where the brackets are attached laterally and medially--and an aluminium profile with a forearm splint (10) attached to its top. This configuration allows the forearm splint (10) to be slid forward or back--distally or proximally--along the aluminium profile. Therefore, the distance between the forearm splint (10) and the proximal finger (11) rest can be reduced or increased, making it adjustable to the length of the patients' metacarpal bones. A mechanical blockage with discrete steps is implemented on the upper part of the bracket (1) to limit the device's range of motion (ROM), ensuring safety and preventing excessive extension of the wrist and fingers. Movement into flexion is limited by the shape of the end segment (9) itself, preventing thumb compression in the flexed position.