A Multicenter Interventional Study on the Use of a 3-Degree-of-Freedom (3DOF) Platform to Evaluate the Safety and Usability of the System and Its Impact on Balance, Proprioception, and Neurological Deficits in the Rehabilitation of Patients With Neurological Disorders.

A Multicenter Interventional Study on the Use of a 3-Degree-of-Freedom (3DOF) Platform to Evaluate the Safety and Usability of the System and Its Impact on Balance, Proprioception, and Neurological Deficits in the Rehabilitation of Patients With Neurological Disorders.

This multicenter interventional study aims to evaluate a three-degrees-of-freedom dynamic platform (3DoF Platform) designed to support rehabilitation of balance, proprioception, and motor and cognitive functions in patients with neurological disorders. The device integrates a mobile platform capable of roll, pitch, and vertical translation movements, a markerless motion-capture system, and an interactive environment delivered through a monitor or virtual reality headset. Compared with conventional rehabilitation systems, it offers an additional vertical degree of freedom and increased proprioceptive stimulation, with the ability to customize exercises according to individual patient capabilities. The clinical conditions under investigation include Parkinson's disease, post-stroke motor impairment, amyotrophic lateral sclerosis, and mild cognitive impairment, all of which are associated with deficits in balance and proprioception. The novelty of this study lies in the combined use of the 3DoF platform, the markerless acquisition system, and exergames integrated with a mathematical model that adapts the platform's dynamic response in real time. The primary objective is to assess the usability, feasibility, and safety of the device. Secondary objectives include evaluating the impact of the intervention on balance, motor performance, cognitive functions, stress, fatigue, and quality of life, as well as comparing conventional rehabilitation with and without the addition of the device. The study involves 45 patients and 15 healthy volunteers and is structured into an initial phase of testing on healthy subjects and a subsequent randomized two-arm treatment phase for patients.

Neurological conditions such as stroke, Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and mild cognitive impairment (MCI) frequently impair balance and proprioception through combined central and peripheral mechanisms. Alterations in muscle spindles, joint mechanoreceptors and cortical grey matter volumes compromise postural control, coordination and the ability to adapt movements without continuous visual feedback. These deficits lead to gait instability, increased risk of falls, traumatic injuries, loss of independence and high healthcare utilisation, especially in ageing populations where multimorbidity and frailty are prevalent. In this context, interventions that can effectively target balance and proprioceptive dysfunction are highly relevant to current healthcare challenges, which include reducing fall-related hospitalisations, supporting safe community living and improving quality of life in people with chronic neurological disease. Conventional neurorehabilitation relies on therapist-guided balance exercises, overground or treadmill gait training and task-oriented activities. These approaches are effective but often limited by the intensity and variability that can be delivered in routine practice, and by the scarcity of objective kinematic data to guide personalised progression. Robotic and moving-platform systems used in research settings have shown that perturbation-based and task-specific balance training can improve postural responses, gait and falls risk in several neurological populations, yet many commercial devices offer only two degrees of freedom and restricted ranges of motion. Evidence on the integration of immersive exergames and virtual reality (VR) into balance training suggests benefits in engagement and cognitive-motor stimulation, but existing technologies are frequently non-adaptive, do not exploit full-body motion capture, and have been evaluated mainly in small, single-pathology cohorts. There remains a gap for multifunctional systems that combine multi-axis mechanical perturbations, markerless motion analysis and immersive exergames, and that are systematically tested in diverse neurological conditions within real clinical workflows. The 3DoF Platform has been developed from a sports-performance motion platform into a device specifically tailored for neurorehabilitation. It provides controlled roll, pitch and vertical translation, coupled with a markerless motion capture system that estimates the position of key body segments and the centre of mass in real time. By linking these kinematic data to an adaptive control model and VR-based exergames, the platform can deliver graded and repeatable balance challenges while maintaining patient safety through harness support and strict software limits on speed and amplitude. The rationale of the present study is to (a) verify that this non-CE-marked device can be used safely and feasibly in routine rehabilitation settings, (b) assess its usability and acceptability for both patients and staff, and (c) explore whether adding 3DoF Platform training to conventional therapy yields measurable benefits on balance, motor performance, cognition, fatigue, stress and quality of life across different neurological conditions. The central hypothesis is that the 3DoF Platform can be safely integrated into multidisciplinary neurorehabilitation pathways, is acceptable and usable for patients and clinicians, and, when combined with standard therapy, leads to superior improvements in balance, proprioception and functional outcomes compared with standard therapy alone.

Primary objectives:

• To assess safety for patients and operators by monitoring adverse events and system errors during all sessions.
• To evaluate usability and feasibility of the device using validated questionnaires and patient-reported measures of stress, anxiety and user experience.

Secondary objectives:

• To quantify the impact of 3DoF Platform training on balance, gait and motor performance using established clinical scales and instrumented markerless measures.
• To assess changes in cognitive performance, perceived fatigue, psychosocial impact and health-related quality of life.
• To compare outcomes between patients receiving conventional rehabilitation plus 3DoF Platform and those receiving conventional rehabilitation alone.
• To develop and validate adaptive software modules that automatically adjust exercise difficulty based on real-time movement analysis.

If the study confirms its hypotheses, the 3DoF Platform could offer clinicians a versatile, data-rich tool to deliver high-intensity, task-specific and engaging balance training within usual care settings. The integration of objective kinematic indicators with standard clinical scales may support more precise stratification of patients, early detection of balance impairments and fine-tuning of rehabilitation programmes over time. For patients, the combination of immersive exergames, personalised difficulty and robust safety measures has the potential to increase motivation, adherence and functional gains, ultimately reducing falls, enhancing autonomy in activities of daily living and improving overall quality of life. At system level, such technology-assisted rehabilitation could contribute to more efficient use of resources by shortening inpatient stays, facilitating safer discharge and enabling structured follow-up interventions in chronic neurological populations.

METHODS This multicenter interventional clinical study evaluates the 3DoF Platform in both healthy volunteers and patients with chronic neurological conditions. According to the protocol (Version 4.0, 27.03.2025), the study includes a total sample of 60 participants: 15 healthy subjects and 45 patients (15 with Parkinson's disease, 10 post-stroke, 10 with ALS, and 10 with mild cognitive impairment). The study follows a two-phase design. An initial phase involves healthy volunteers undergoing screening, device training and repeated testing sessions to assess safety, usability and feasibility, as well as to collect baseline normative data. A second phase adopts a simple randomization scheme assigning 40 patients to two groups: conventional rehabilitation alone or conventional rehabilitation combined with 3DoF Platform training. Both groups complete twelve 60-minute conventional therapy sessions, while the experimental arm receives additional sessions (up to 30 minutes) on the 3DoF Platform, including exercises and short exergame tasks. The interventions tested consist of: (1) standard rehabilitation delivered according to clinical practice, and (2) additional training on the dynamic 3DoF Platform, which provides controlled roll, pitch and vertical translation, markerless motion capture, and VR or monitor-based exergames. Outcome measures include the protocol's primary endpoints: usability, feasibility and safety of the device. Secondary endpoints evaluate the impact on balance, motor performance, cognitive functions, stress, fatigue and quality of life, as well as the comparison between the two treatment arms and the validation of adaptive exercise software. Statistical analyses described in the protocol include data summarization and comparison between the two study groups to evaluate treatment effects on all clinical and functional measures. All deviations, adverse events and system errors are documented to support safety and feasibility assessments. Regarding preliminary results, the study is currently awaiting the fourth revision by the Italian Ministry of Health. Nevertheless, the device has already been introduced in the clinical setting, and 22 pre-clinical tests on healthy participants, also requested by the Ministry, have been successfully completed.

Inclusion Criteria:

• Patients: adults aged 18 to 80 years.
• Patients: confirmed diagnosis of one of the following chronic neurological conditions: stroke, Parkinson's disease, amyotrophic lateral sclerosis (ALS), or mild cognitive impairment (MCI).
• Patients: able to understand and follow study procedures and provide informed consent.
• Healthy volunteers: adults aged 18 to 65 years.
• Healthy volunteers: able to understand and follow study procedures and provide informed consent.
• Healthy volunteers: rehabilitation staff members from the participating centers.

Exclusion Criteria:

• Patients: severe psychiatric disorders or cognitive disorders that impair the ability to complete cognitive tests and self-report questionnaires.
• Patients: unable to provide informed consent.
• Patients: moderate to severe cognitive impairment, defined as an ECAS score below 81.92 in participants with ALS or a Raven's Matrices score below 18.36 in participants with mild cognitive impairment.
• Patients: neurological or physical conditions that significantly limit lower-limb use and prevent standing on the platform, including lower-limb muscle strength of 3 or less on the Medical Research Council (MRC) scale.
• Patients: body weight greater than 100 kg.
• Patients: current or recent participation, within the last 3 months, in other rehabilitation programs or interventions that could affect study results.
• Patients: alcohol or substance dependence that could compromise safety during training sessions.
• Patients: unstable health conditions that could make use of the 3DoF Platform and/or head-mounted display unsafe or inappropriate, such as severe cardiovascular disease, severe respiratory disease, or other unstable medical conditions.
• Healthy volunteers: health conditions that could make use of the 3DoF Platform and/or head-mounted display unsafe or inappropriate, such as severe cardiovascular disease, severe respiratory disease, or other unstable medical conditions.
• Healthy volunteers: any motor disability.