Assessment of Feasibility, Functionality and Usability of an Hybrid Assistive Exoskeleton for Upper Limb

Number of device failures and malfunctioning, device-related harms during device use

The box and block test measures how many cubic wooden blocks the subject is able to move from one side of a wooden box to the other side in 60 seconds. The subject is asked to perform the Box And Blocks test while wearing the device and without the device for comparison.

The subject is asked to perform different ADLs while wearing the device and without the device. Time for the execution and successful rate of activities are registered for comparison.

The subject is asked to perform the box and block test, maximum reaching height task and activites of daily living while wearing the device in assitive mode and without the device. The experimental setup is provided with Magneto-Inertial Measurement Unit (M-IMU) sensors capable to measure speed and smoothness of movements in both cases for comparison.

The subject is asked to perform the box and block test, maximum reaching height task and activites of daily living while wearing the device in assitive mode and without the device. The experimental setup is provided with surface EMG sensors capable to measure upper limb muscles activation in both cases for comparison.

SUS is a questionnaire aiming at measuring the perceived usability of the device. It's a 10-item questionnaire, 5-points Likert scale with item score ranging from 1 (strongly disagree) to 5 (strongly agree). In SUS score calculation, each item's score contribution will range from 0 to 4 with the final score obtained by summing the score contributions from each item and multiplying it by 2.5, in order to have a value in the range of 0 to 100. The higer the final score, the better the outcome.

QUEST is a questionnaire aiming at measuring the perceived satisfaction of the device after use. It's a 12-item questionnaire, with item score ranging from 1 (worst) to 5 (best). The final score is obtained as an average of the items scores. The higer the final score, the better the outcome.

A custom NRS 0-10 is created to measure the perceived level of acceptance of the device after use. The subject is asked to evaluate its perception of weight, comfort, safety and assistance wearing the device, with item score ranging from 0 (best) to 10 (worst). The higher the scores, the worse the outcome.

The subject is asked to evaluate its level of musculoskeletal pain after use with a score ranging from 0 (no pain) to 10 (max pain). The higher the score, the worse the outcome.

NASA-TLX is used with the aim of measuring the effectiveness of the device after use. It is a multi-dimensional rating procedure that provides an overall workload score based on a weighted average of ratings on six subscales: Mental Demands, Physical Demands, Temporal Demands, Own Performance, Effort, and Frustration. For each task or group of tasks, the subject is asked to select an option for each of the 15 comparison cards given (to obtain weights) and to express a score ranging from 1 (low/good) to 20 (high/poor) for each subscale (rate). The final workload score is computed by multiplying each rating by the weight given to that factor by that subject, then the sum of the weighted ratings for each task is divided by 15. The higer the final score, the worse the outcome.

FSS is a questionnaire aiming at measuring the user experience of the device during use. It's a 36-item questionnaire, with item score ranging from 1 (strongly disagree) to 5 (strongly agree). As 5-point Likert scale with 4 items per 9 subscales, the item scores for each dimension are summed and then divided by four, to obtain flow dimension item-average scores. The higer the final score, the better the outcome.

Borg CR-10 Scale is a subjective measure of perceived exertion or intensity during the execution of tasks. Body sensations under evaluation concern heart rate, breath rate and muscle fatigue with item score ranging from 0 (nothing at all) to 10 (maximum). The higher the single scores, the worse the outcome.