The goal of this randomized clinical trial is to find out whether an early neuro-functional rehabilitation program using virtual reality and action observation can improve recovery after a traumatic injury of the wrist or hand that requires immobilization in a cast or splint.

After a fracture or other traumatic injury, the wrist and hand often have to be immobilized for several weeks. This rest is necessary for the bone and soft tissues to heal, but it also has negative effects. The muscles become weaker, joint movement is reduced, and the sense of position and movement (proprioception) worsens. Immobilization also produces fast changes in the brain areas that control movement, which may slow down recovery and increase the risk of long-lasting pain, stiffness, and disability.

This study will compare two rehabilitation programs:

Control group: participants will receive conventional rehabilitation after the cast or splint is removed, following the usual care of the hand therapy and traumatology services.

Experimental group: in addition to conventional rehabilitation, participants will follow a specific program that combines action observation therapy with immersive virtual reality (AOT+VR). During each session, patients will watch first-person videos of functional wrist and hand movements through a virtual reality headset and then practice these same movements. The program includes about 12 sessions of 45 minutes over 6 weeks, starting during the immobilization period and continuing after the cast or splint is removed.

Adults between 18 and 70 years with traumatic injuries of the wrist and/or hand (such as distal radius, carpal or metacarpal fractures, or tendon and ligament injuries) who need immobilization for 2 to 8 weeks will be invited to participate.

Researchers will measure:

Sensorimotor cortical activity associated with action observation and execution using electroencephalography (EEG), pain, disability, and function of the upper limb using validated questionnaires, Physical measures such as wrist range of motion, grip strength, and proprioception, Psychological factors such as fear of movement and pain catastrophizing, Feasibility, adherence to the program, side effects, and patient satisfaction. The main hypothesis is that the AOT+VR program, started early during immobilization, will help maintain brain excitability, reduce pain and psychological barriers, and lead to faster and more complete functional recovery of the wrist and hand compared with conventional rehabilitation alone.

Traumatic injuries of the wrist and hand are common causes of disability of the upper limb in adults. They frequently require a period of immobilization in a cast or splint to allow bone and soft tissues to heal. However, prolonged immobilization is associated with muscle atrophy, reduced strength, joint stiffness, proprioceptive deficits and, importantly, rapid neuroplastic changes in the motor cortex and related brain networks. These changes contribute to a maladaptive pattern of "disuse plasticity" that may persist after immobilization and is linked to chronic pain, fear of movement, and incomplete functional recovery.

Recent research shows that brain plasticity can be positively modulated through interventions based on motor representation, such as motor imagery and action observation therapy (AOT). In AOT, patients watch goal-directed movements that are similar to the actions they need to relearn. This activates the mirror neuron system and motor cortical areas even when the limb is not actively moving. Immersive virtual reality (VR) can enhance these effects by providing a first-person, three-dimensional environment that increases attention, motivation, sense of presence, and perceived control.

This study proposes an early neuro-functional intervention that combines AOT with immersive VR (AOT+VR) during and after the immobilization period in patients with traumatic wrist and hand injuries. The trial is designed as a randomized, controlled, parallel-group clinical study. Eligible participants (18-70 years, traumatic wrist/hand injury requiring 2-8 weeks of immobilization) will be randomly assigned to:

a control group, receiving only conventional rehabilitation according to standard clinical practice after immobilization, or an experimental group, receiving the same conventional rehabilitation plus the structured AOT+VR program.

The experimental protocol consists of approximately 12 sessions (±2), 45 minutes each, delivered twice per week over 6 weeks. In each session, participants use a VR headset (Meta Quest 3S) to observe videos of functional, uni- and bimanual upper-limb tasks from a first-person perspective (for example, reaching, grasping objects, using cutlery, writing, or daily-life activities). After each observation period, the headset is removed and the participant executes the observed movements with the affected limb as tolerated, repeating this observation-execution cycle several times per session. Exercises progress gradually from simple movements without gravity to complex functional tasks, allowing individual adaptation. Sessions are stopped immediately if adverse effects such as dizziness, nausea, or disorientation appear.

Outcome assessments are performed at three time points: baseline (within the first 5 days after starting immobilization), post-immobilization (24-48 hours after cast or splint removal), and follow-up (6 weeks after post-immobilization).

The primary outcome is sensorimotor cortical activity associated with action observation and execution, assessed using electroencephalography (EEG). Neurophysiological markers include event-related potentials (ERPs) time-locked to action observation and execution tasks, and event-related desyinchronization/synchronization (ERD/ERS) within the mu (8-13 hz) and beta (13-30 hz) frecuency bands over sensorimotor cortical regions. Secondary outcomes include pain and perceived disability (PRWE, QuickDASH, MHQ, SPADI), psychological factors (Tampa Scale of Kinesiophobia-11, Pain Catastrophizing Scale), physical measures of wrist range of motion, grip strength, proprioception, and feasibility and safety indicators (recruitment and adherence rates, adverse events related to VR or TMS, completeness of data and participant satisfaction).

The central hypothesis is that early AOT+VR will attenuate the reduction in sensorimotor cortical activity associated with immobilization, support more adaptive brain reorganization, and lead to better clinical outcomes than conventional care alone. By integrating neurophysiological, functional, and psychological measures, the study aims to clarify the mechanisms of action of AOT+VR and to determine whether this low-risk, technology-supported intervention is feasible and acceptable in real clinical settings for early rehabilitation after traumatic wrist and hand injuries.

Inclusion Criteria:

• Age 18-70 years old.
• Diagnosis of traumatic wrist and/or hand injury within 5 days of injury onset.
• Traumatic injury types include: distal radius fractures, scaphoid fractures, metacarpal fractures, phalangeal fractures, other carpal bone fractures, tendinous injuries, or ligamentous injuries.
• Require immobilization with cast or splint for 2-8 weeks.
• Ability to provide written informed consent.
• Ability to understand and follow study instructions.
• Sufficient mobility and residual manual capacity to participate in virtual reality sessions and physical assessments.

Exclusion Criteria:

• History of neurological disease affecting motor control (stroke, Parkinson's disease, multiple sclerosis).
• Severe psychiatric disorders (psychosis, severe depression requiring hospitalization).
• Current involvement in other rehabilitation protocols or clinical trials.
• Contraindications for using virtual reality.

Participants will be anonymized with a number and randomized with a web program (random.org)