A Novel Shape Memory Alloy-Based Orthosis for Proximal Interphalangeal Joint Stiffness

Active, passive and torque range of motion are common measurements to assess joint mobility limitations in clinical settings. Active range of motion is measured as the maximum movement achieved by the patient's own efforts. Passive range of motion is measured when an external force, such as a therapist, moves the joint until the end feel is detected. Torque range of motion is assessed with a specific tension applied to the movement of interest. Normal proximal interphalangeal joint flexion range of motion typically ranges from 0-100 or 110 degrees.

The Minnesota Manual Dexterity Test assesses fine manual dexterity and consists of two subtests: the placing and turning tests. These involve hand movements such as picking up, turning, transferring, and placing disks. Each subtest includes two trials, resulting in a total of six trials. The combined time taken to complete both trials in each subtest will be recorded.

The Purdue Pegboard Test assesses fine motor coordination and manipulative ability through four subtests: dominant hand, non-dominant hand, both hands, and assembly. In each subtest, participants place as many pins as possible in the designated column, with the assembly subtest also incorporating washers and collars. The allotted time is thirty seconds for the dominant hand, non-dominant hand, and both hands subtests, and sixty seconds for the assembly subtest. Each subtest is repeated three times, and the average of these three trials is calculated as the final score.

The motion capture system will be used to measure the functional range of motion of the hand. It utilizes standard cameras or Vicon motion capture system to record hand movements of participants. The data is further analyzed using tools such as MATLAB, Mediapipe, or other motion analysis software to assess the functional range of motion of the hand.

The Taiwan version of the Disability of the Arm, Shoulder, and Hand Questionnaire is a 30-item, self-reported tool used to assess hand function, specifically addressing physical function and symptoms in patients with upper limb musculoskeletal disorders. It provides a detailed view of patient disability and tracks changes in symptoms and function over time. Each item is scored on a 5-point Likert scale, where 1 represents no difficulty and 5 represents inability to perform the task. Responses are based on the patient's experiences from the past week, with scores converted to a 0-100 scale, where higher scores indicate greater severity of disability.

The System Usability Scale assesses the usability of the SMA-based orthosis. It evaluates effectiveness and satisfaction from the user's subjective perspective. The scale contains 10 items, each with five response options, where 1 means "Strongly disagree" and 5 means "Strongly agree". Participants' scores for each item are converted to range from 0 to 4. For items 1,3,5,7, and 9, the converted score is the participant's scores minus 1. For items 2,4,6,8 and 10, the converted score is 5 minus the participant's scores. The sum of these scores is then multiplied by 2.5 to obtain the overall usability value.