The aim of the study is to assess the efficacy and the usability of the cyberlegs ++ ortho prosthesis to improve the mobility and the quality of life in transfemoral amputees . This research focusses on the physical and mental effort needed in locomotion-related tasks and human robot interaction in transfemoral amputees using a novel active prosthesis. This is an international project and foresees 2 clinical studies aimed at assessing the efficacy of the CLs++ modules in different settings.

In this first clinical study, 16 patients with unilateral trans-femoral amputation, 8 at the Vrije Universiteit Brussel Department Human Physiology Research group (VUB-MFYS) and 8 at the Don Gnocchi Foundation, center of Florence.

The aim of the study is to assess the efficacy and the usability of the cyberlegs ++ ortho-prosthesis to improve the mobility and the quality of life in transfemoral amputees. This research focusses on the physical and mental effort needed in locomotion-related tasks and human robot interaction in transfemoral amputees using the CLs++ ortho-prosthesis modules. Unilateral transfemoral amputees will be recruited by a multidisciplinary team (physicians, physiotherapists and psychologists) and a list of inclusion- and exclusions criteria as reported in the 'Eligibility' will be fulfilled to enrol the experiment. If the participant fulfils the requirements to be enrolled, the responsible for the study will provide him/her with the information sheet and will answer all possible questions. Once the participant agrees to participate in the study, he/she will sign the informed consent form and an appointment will also be arranged with the orthopedic workshop to make a spare socket to be used during the clinical testings. In this first clinical study, a set of modules of the three hardware (HW) modules of the CLs++ ortho-prosthesis will be tested, namely the Active Trans-femoral Prosthesis (ATP), the Active Pelvis Orthosis (APO) and the Knee Ankle Foot Orthosis (KAFO).

Each subject will be testing the different combinations of CLs++ modules along with the Wearable Sensory Apparatus (WSA) and the control software (SW):

1)APO+WSA, 2) ATP+WSA, 3) APO+ATP+WSA, 4) APO+KAFO+WSA.

The protocol of the CLs++ first clinical study will be constituted by two main phases:

The initial Phase/familiarization phase:

The appropriate combination of the CL++ modules will be selected based on the clinical evaluation (e.g. walking asymmetry, flexion-extension, hip strenght, strength of the contra-lateral limb) and the subjective feedback in terms of comfort and perceived functionality from the participant. The subjects will be asked to walk at their self-selected speed on a treadmill. To control all variables the functional assessments above will be performed on a treadmill, however, when possible gait related tasks and ancillary tasks will be performed during over-ground walking to asses functional exercise capacity:

• Six Minute Walking Test (6MWT)
• slope walking
• The Timed Up and Go test (TUG) to evaluate balance, Chair standing/sitting.
• The Stair Climbing Test (SCT) to asses stair climbing Electrophysiological and biomechanical parameters will be collected to tell us wether there is an advantage in the use of the novel active prosthetic device in comparison with the current prosthesis only.

The outcomes measures in this study are:

• Electroencephalography (EEG) to record cortical brain activity using an Electro-Encephalography cap (EEGcap, Brain Products GmbH),
• Indirect measurement of the energy expenditure by measuring the oxygen uptake and the produced carbondioxide (ml/min/kg, portable gasanalyzer,Cosmed K5)
• Heart rate (Polar heart rate monitor)

The study foresees the administration of dedicated questionnares to asses the workload such as:

• The Short Form-36 (SF-36) Report of perceived exertion (RPE)-Borg Scale, self-report of the perceived physical effort scale.
• The National Aeronautics and Space Administration task Load indeX (NASA-TLX)
• The System Usability Scale (SUS) to asses the usability of the CLs++ system.
• The SF-36 (short form-36 item) at baseline The subjects will conduct 2 experimental trials during the initial phase, this is with the CLs++ modules and with their current prosthesis only. The participant can rest between the assessments to let the patient recover, with at least 15-30 minutes.

The second phase of the study consist of a intervention, this is a gait training program on the treadmill with the selected combination of CLs++ modules, 1 hour, 3 times a week. Participants will be asked to walk at their self-selected speed and they will be allowed to stop walking whenever they feel tired. At the end of each month we asses wether the experience gained in the training period has effects.

Data of each patient will be analysed separately in order to highlight the occurence of differences between pre- and post- assessment sessions. This is a non-randomized cross-over research, a sample size of 16 subjects will be able to detect a 15% change in walking-related physical effort, in terms of energy expenditure in a single group of trans-femoral amputees with a statistical power >0.9 at the two-sided alpha-level.

Inclusion Criteria:

Unilateral trans-femoral amputees both sex age: 30 - 80 yrs Functional K-level 1-4

Exclusion Criteria:

• Severe comorbidity (hemiplegia, degenerative nervous system diseases, severe hip or knee arthrosis,chronic heart failure, chronic obstructive pulmonary, hip or knee replacement, severe sensory deficit
• Pain of the stump/socket poor fitting
• Inability to walk (safely) on a treadmill