The primary objective of this study is to evaluate the safety, reliability and short-term effectiveness of APO-based training to increase the self-selected walking velocity (SSV) of stroke patients. The robotic device is the Active Pelvic Orthosis RT v3.1 (IUVO APO) developed bu IUVO S.r.l.

The primary objective of this study is to evaluate the safety, reliability and short-term effectiveness of APO-based training to increase the self-selected walking velocity (SSV) of stroke patients. The endpoint to evaluate the APO-based training effectiveness will be the difference in self-selected walking velocity (m/s) comparing post-training session (T4) to baseline sessions (T1&T2).

Other objective of the study, both secondary and exploratory, have been defined to further investigate the effects of the IUVO APO on post-stroke subjects.

The Investigational Device, Active Pelvis Orthosis RT v3.1 (APO), is a bilateral powered robotic hip orthosis (or exoskeleton) designed to gently assist hip flexion-extension movements by providing smooth assistive torque at the hip level, automatically adapting to natural gait variations.

The study will be an interventional single-arm clinical trial with no control group and will involve up to 20 subjects, that fulfil the inclusion/exclusion criteria. This should be sufficient to provide the input needed to reach the primary and secondary objectives of the trial.

In the protocol, after the screening visit, subjects will take part in 14 experimental sessions: two baseline sessions (T1-T2), three familiarization sessions (F1-F3), six training sessions (E1-E6), two assessment sessions (one pre-training T3 and one post training T4) and one 2-month follow-up session (T5). Depending on the session, the subject will be asked to walk with or without the APO, or both. During the assessment sessions, the subject will be evaluated through different standard tests (such as 10MWTs and 2mWTs) and instrumented gait analysis, with and without APO. In the training sessions, the subject will perform some overground walking practice with APO.

Inclusion Criteria:

• cerebral stroke;
• at least 3 months from cerebral event;
• hemiparesis;
• age > 18 years;
• SSV greater than 0.3 (m/s);
• SSV less than 0.8 (m/s);
• ability to ambulate with no more than minimal contact assistance;
• maximum hip width range, i.e., distance between Great Trochanters = 430 mm.

Exclusion Criteria:

• Modified Ashworth Scale >3 at the hip and/or ankle joints;
• inability to follow verbal 3 step commands;
• severe aphasia causing inability to communicate with the investigators;
• serious medical conditions (recent myocardial infarction in less than 3 months, uncontrolled congestive heart failure (CHF), uncontrolled hypertension, uncontrolled seizures);
• leg deep vein thrombosis less than 6 weeks ago;
• other pre-existing neurological disorders (Parkinson's disease, Amyotrophic Lateral Sclerosis, Multiple Sclerosis, Dementia);
• Severe osteoporosis;
• severe hip / knee osteoarthritis with limitation of movement or significant pain;
• use of a colostomy bag;
• skin wounds, infection or problems at device contact locations;
• major orthopedic surgery or fractures within the last 90 days (hip, knee, ankle, foot, spine);
• cardiac surgery within the last 3 months;
• patient has recently or is currently participating in research that may influence, in PI's opinion, responses to study intervention;
• pregnancy;
• breastfeeding woman;
• implanted cardiac devices (pacemakers, ICDs);
• use of assistive device that, in the PI's opinion, could interfere with APO;
• it is recommended that participants treated with anti-spasticity agents (oral, injectable or intrathecal) keep the dosage for these medications constant throughout the study;
• where medically appropriate, all other concomitant medications being taken by a participant at entry into the study should continue at the same dose until end of study.