Clinical Evaluation of Intuitive, Bidirectional Strategies for the Control of Multi-articulated Prostheses for Upper Limb Amputation

The test consists of sequentially manipulating 6 lightweight and 6 heavyweight abstract objects and 14 activities of daily living over a specific formboard. Lightweight objects should be manipulated first. The task involves pushing a button to start a timer, picking up and moving the object from the rear slot to the front slot on the board, and completing the task by depressing the button on the timer again.

The objective is to evaluate the performance of a prosthetic user in a controlled environment and subsequently provide a measure of the user's expected functionality level outside the laboratory/clinic. The user is instructed to allocate three clothespins between a horizontal rod and a vertical rod and asked to fill out a post-test survey after five trials of the CRT.

The PLT measures motor coordination, i.e., the ability to coordinate the grip force and the load force while lifting an object, as well as the reliability of the recorded control signal while transporting the object. While the subject is sitting on a chair with the intact arm parallel to the trunk, and the amputated limb extending anteriorly on a table, he/she is asked to lift a small object from the table with the prosthesis.

The VET resembles the task of transporting fragile and robust objects, thus requiring both gross and fine dexterity. The test is composed of 11 Virtual Eggs that collapse if the grasping force exceeds their breaking thresholds, ranging from 0.4 N to 11.5 N. The test aims to transport each Virtual Egg over the barrier in the centre of the test platform without breaking it and as fast as possible. The metrics measured during the test are combined and provide two indexes that evaluate, respectively, gross and fine dexterity.

The prosthesis, for as long as it is powered, will log real-time information about its usage during the day. Such data will allow us to calculate the total wear/use time, as well as the quality of the usage (which moments are used and how often). The data should also provide basic information for debugging in case of system failures and adverse events.

The NASA-TLX is a questionnaire to assess subjective workload, in terms of mental, physical, temporal, performance, effort and frustration. The resulting score ranges from 0 to 100, where 0 means no workload (very easy) and 100 means maximum workload (extremely demanding).

The abilHAND-ULA is a questionnaire for self-assessing the perceived manual ability for individuals with upper limb amputation. The cumulative score ranges from 0 to 66, with higher scores indicating better manual ability.

The Orthotics and Prosthetics User's Survey - Upper Extremity Functional Scale for Prosthesis Users (OPUS-UEFS) is a self-report measure designed to assess the functional status of individuals using upper limb prostheses, considering the level of amputation and prosthesis type. Each of the 23 items is rated on a 5-point scale (0 = cannot do this activity, 5 = very easy). The cumulative score ranges from 0 to 92, with higher scores indicating greater functional ability.

The Trinity Amputation and Prosthesis Experience Scales (TAPES) is a self-administered questionnaire that comprises psychosocial adjustment, activity restriction, and prosthetic satisfaction domains, each with 3 subscales. Each subscale is scored individually, with higher scores consistently indicating more positive outcomes. Summing scores across different subscales is not appropriate.

The Disability of the Arm, Shoulder and Hand is a self-administered questionnaire aimed at evaluating upper limb function. It is a 30-item questionnaire (main section) where each item is rated from 1 to 5 for increased difficulty/severity. The overall score ranges from 0 to 100.

The System Usability Scale (SUS) is a ten-item attitude Likert scale giving a global view of subjective assessment of usability. Users respond to 10 statements, rating them from 1 (Strongly Disagree) to 5 (Strongly Agree). The higher the score, the higher the perceived usability. Usually a score of 68 is the average industrial benchmark, and a score >80 is considered as excellent.