The investigators propose to validate a non-invasive upper limb prosthesis capable of combining: 1) intuitive movement control through machine learning applied to myoelectric signals, and 2) vibrotactile sensory feedback in response to touch and object release events. The prosthesis is composed at the minimum of skin-surface electrodes for myoelectric signals, vibrotactile actuators, a multi-articulated and instrumented hand prosthesis and a centralized control system. Such system is validated for several weeks in non-supervised environments.
subjects with transradial amputation, and minimum experience in the use of myoelectric prosthesis;
subjects who have expressed informed consent to participate in the study and consent to data processing.
subjects with obvious visual and oculomotor defects;
concomitant comorbidities/disabilities/chronic conditions, general or localized (Multiple Sclerosis, Parkinson's disease, muscle tone disorders, malignant neoplasms, etc.), which may interfere with the performance of the study;
pregnancy or breastfeeding;
declared or evident cognitive deficits that compromise the understanding of the required tasks (mini Mental State Examination≤ 24);
Crossover
Prosthetic controller
DeviceThe intervention includes an upper limb prosthesis composed at the minimum by skin-surface electrodes for myoelectric signals, a vibrotactile actuator, a multi-articulated and instrumented hand prosthesis and a centralized control system. The centralized prosthetic controller processes the myoelectric signals acquired at the residual limb to enable the movements on the multi-articulated prosthesis.
Southampton Hand Assessment Procedure (SHAP)
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.
Clothespin Relocation Test (CRT)
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.
Pick and Lift Test (PLT)
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.
Virtual Egg Test (VET)
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.
NASA-TLX questionnaire
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).
abilHAND-ULA
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.
OPUS-UEFS
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.
TAPES
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.
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Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna
Lead sponsor
IRCCS Istituto Ortopedico Rizzoli di Bologna
Collaborator
