Introduction

Virtual reality (VR) has transitioned from a speculative technology to a clinically validated tool in neurorehabilitation, offering unique opportunities to address the complex needs of neurocritical care patients. Survivors of traumatic brain injury (TBI), ischemic and hemorrhagic strokes, subarachnoid hemorrhage (SAH), and hypoxic-ischemic encephalopathy (HIE), along with patients with autoimmune neurological diseases such as multiple sclerosis (MS) or Guillain-Barre syndrome (GBS) or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) can face numerous long-term challenges related to their motor deficits, cognitive impairment, psychological distress, and/or prolonged immobilization. These patients frequently require early, intensive rehabilitation to maximize their functional recovery and minimize long‐term disability. Recently, VR has emerged as a transformative adjunct to conventional therapies^{1, 2}. By creating dynamic, immersive, and task-specific environments, VR can foster neuroplasticity and reengage damaged neural circuits. In this article, we provide an overview of the latest evidence and clinical strategies for VR technologies that may be relevant for neurocritical care specialists in current and future practice.

Mechanistic Foundations

Mirror Neuron Activation and Virtual Embodiment

VR mirror therapy leverages the mirror neuron system by reflecting movements of an intact limb, thereby “tricking” the brain into activating motor pathways of the affected side. The visual reappearance of self-actions in the VR scene has been shown to further stimulate the activity of affected cortical areas and promote their functional integration, especially in stroke patients. It is thought that VR-based motor imagery exercises may increase cortical mapping of areas corresponding to the muscle being trained and excitability of the corticospinal tract, with the end result of facilitating motor relearning^3-5.

Cortical Reorganization

This principle is believed to be due to cross-modal plasticity via multi-sensory stimulation. By concurrently engaging visual, auditory, and proprioceptive systems, VR can create a rich sensory experience that is thought to encourage synaptic reorganization in specific locations that depend on the type of training and VR system utilized. This has been demonstrated to facilitate motor learning after stroke through reorganization from aberrant ipsilateral sensorimotor cortices to the contralateral side. VR environments that combine auditory cues with visual stimuli in TBI and stroke patients with hemianopia or neglect are further proof-of-principle examples that can help improve compensatory scanning and/or neglect in these patients.^{3, 6-11}

Error-Based Learning / Real-Time Feedback & Adaptive Learning

Advanced VR platforms can capture real time kinematic data, allowing for immediate feedback and task adjustment. This closed-loop system can mirror principles of motor learning by reinforcing correct movements and discouraging maladaptive patterns. Evidence suggests that such feedback can facilitate the strengthening of residual pathways and accelerate recovery. This has been demonstrated through improvements in balance in multiple neurologic illnesses. Another example is that some VR systems use error augmentation and biofeedback (e.g., magnifying tremors in a virtual task) to force corrective adjustments.^{10, 12, 13}

Reward Mechanisms and Cognitive Engagement

Gamification and immersive scenarios can stimulate dopaminergic pathways, especially those in the ventral striatum, which are crucial for motivation and learning. The interactive, goal-oriented nature of VR can help increase patient adherence while also enhancing cognitive functions such as attention, memory, and executive control.

Modalities

In general, a key differentiating factor between various VR modalities is the level of immersion they provide. They are typically categorized broadly as immersive, semi-immersive, or non-immersive, albeit with some gray area in between. There is some thought that the level of immersion may play a role in the efficacy of rehabilitation by allowing for the translation of trained skills into the real world. As a result, it may be possible that semi-immersive and non-immersive modalities are less effective, but more research is needed to better understand the optimal level of immersion for VR-based intervention effectiveness.

Immersive VR systems

Immersive VR technologies utilize head-mounted VR displays paired with motion tracking sensors and sometimes haptic feedback devices. This type of VR has the benefit of providing the most personalized neurorehabilitation customized to individual needs. This can be useful for a variety of tasks, such as intensive cognitive tasks, or for simulating more realistic environments that are otherwise difficult to emulate. Potential uses of haptic feedback range from quasi-glove devices to provide fingertip vibration feedback during virtual object manipulation for proprioceptive rehabilitation to the use of exoskeletons for fine motor tasks or ambulation.^{10, 14, 15}

In addition to highly individualized arrangements, multiplayer immersive systems also exist. The level of immersion is similar, except multiple patients would participate simultaneously within a shared virtual space. This has the advantage of promoting social interaction and specific types of cognitive functionality.

Semi-immersive VR systems

Semi-immersive VR systems aim to integrate immersive technology with physical interaction in the real world. These may still utilize VR helmets, handheld controllers, and motion capture systems, which can provide the perception of being in a different reality when focused on a digital image while allowing a patient to remain connected to their physical surroundings. For example, a 3D space that patients can move about on their own, either through a VR headset or a large screen with motion-capture devices, has the benefit of intuitive implementation and allowing for easier monitoring and assistance by therapists compared to some non-VR settings. It has been especially useful in the domains of cognitive rehabilitation and balance and gait training.^15,16

Non-immersive and hybrid systems

Non-immersive systems provide VR rehabilitation that utilizes non-immersive media and widely used tools such as tablets, desktop computers, and other mobile devices, often integrated with external cues. However, these systems can also include augmented reality technologies, which overlays virtual cues onto the real world. This has the benefit of ease of use and setup and a more intuitive interface for the patient. Moreover, it is generally more affordable than many other options, making it more suitable for large-scale utilization.^15,16

Clinical Applications and Evidence

Motor Rehabilitation

There is a strong need for motor rehabilitation across a wide variety of neurological diseases, and VR-based rehab has been investigated on numerous fronts. A broad systematic review by Massetti et al. found that VR rehabilitation interventions were associated with a range of benefits that extended beyond the initial period of acute hospitalization and traditional post-acute rehabilitation, including improved upper limb motor function, balance and gait, strength, overall fitness, and range of motion.¹² They also highlighted the added benefits of VR as an adjunct to traditional rehabilitation. In an umbrella review of 41 meta-analyses, Voinescu et al. found that VR-based neurorehabilitation was associated with benefits ranging from improved balance, mobility, upper extremity function, and body function in stroke patients, improved upper extremity function in patients with acquired brain injury, and improved ambulation in patients with cerebral palsy.¹⁷ However, the authors noted that the overall quality of evidence was predominantly low or very low, emphasizing the need for high quality randomized controlled trials are needed to further investigate these findings. A systematic review of VR-based therapy for TBI patients found the highest benefit in cognitive domains but did note moderate improvements in gait and balance in some patients with milder TBI.¹⁸ Other studies and reviews have also demonstrated benefits in patients with MS, Parkinson’s disease, and spinal cord injury.^{1, 12, 19-22} In general, VR technologies do not replace conventional methods of rehabilitation but may provide added benefit as an adjunct to therapy.¹⁷

Cognitive Rehabilitation

The use of VR-based rehabilitation to augment recovery of cognitive domains has been a burgeoning area of interest. VR technology has the advantage of providing a safe environment to hone skills that may otherwise be too risky to perform, such as driving, cooking, or accessing bank accounts and ATMs, while also providing the option to gradually increase the difficulty of a task as a patient progresses. As such, VR has been shown to improve cognitive flexibility, shifting skills, and selective attention in survivors of acute brain injury, while aiding post-stroke cognitive and psychological recovery via improved attention, memory, and mood.¹⁶ Further, improvements in domains such as selective memory processes and specific problem-solving skills can aid in patients’ reintegration into social settings and lead to better long-term vocational outcomes. Overall, there may be significant benefits associated with VR in cognitive rehabilitation, although evidence is somewhat less robust than with motor rehabilitation. Because of heterogeneity and a lack of standardization in the assessment of various cognitive domains in previous studies, additional research is needed to further examine the benefits of VR in these domains.

Critical and Neurocritical Care Specific Applications

There is limited data on VR-based neurorehabilitation within the ICU, and especially within the neurocritical care unit. Theoretically, VR could be a preferred modality for critically injured patients for whom physical mobilization could be contraindicated or very risky. Patients could utilize a range of VR technology depending on their stage of recovery, and their ability to begin the rehabilitation process early while still restricted to the bed could be a great advantage and potential opportunity for this technology. While this could be especially useful in cognitive and psychological domains, it may also have early benefits for motor rehabilitation, even without actual movement (e.g., haptic feedback with visual object manipulation to stimulate motor pathways) and could facilitate earlier mobilization and bridging over to more conventional types of therapy. This may provide immense benefits in these patients, as multiple investigations have suggested that early rehab following various acute brain injuries is associated with better outcomes, including reduced hospital length of stay, improved long-term functionality, and an improved ability to perform activities of daily living. ^23-25

Although data are limited, some VR rehabilitation systems tested within ICU settings have demonstrated psychological and cognitive benefits in early studies. In a proof-of-concept pilot study in 20 ICU patients who were either intubated or recently extubated, Turon et al. found that the semi-immersive ENRIC (Early Neurocognitive Rehabilitation in Intensive Care) VR platform was safe, feasible, and enjoyed by patients, while appearing to be associated with autonomic reactivity that suggested cognitive stimulation.²⁶ In a follow-up study by Navarra-Ventura et al., ³⁴ intubated patients given early neurocognitive stimulation via ENRIC had significantly better working memory scores and less depression and anxiety at follow-up compared to 38 patients who received usual treatment. ²⁷ Meanwhile, the E-CHOISIR (Electronic‑CHOIce of a System for Intensive care Relaxation) trial of different electronic relaxation devices suggested that semi-immersive VR devices may have benefits in critically ill patients with respect to decreased stress, discomfort, and pain.²⁸

As for benefits on motor rehabilitation, a study by Parke et al. in 20 ICU patients utilizing a non-immersive Jintronix VR system targeting trunk and extremity strength found that this intervention was associated with improved body strength and range of motion, as well as high patient ratings related to enjoyment and motivation (which may have an impact on patients’ rehabilitation outcomes)²⁹. On the other hand, another study of 60 ICU patients specifically investigating changes in grip strength when utilizing a non-immersive VR system (Nintendo Wii) did not find a significant benefit ³⁰. Despite this, a recent systematic review of 11 randomized controlled trials involving 880 ICU patients demonstrated that VR-based rehabilitation had a better overall effect in motor domains than conventional rehab, including extremity motor function, walking, and improving balance.³¹ However, as above, outcomes may be impacted by the level of VR immersion; additional studies with more standardized approaches are needed to validate these findings.

Challenges and Limitations

Certain limitations for these technologies do exist. First, many patients experience cybersickness and sensory overload, developing motion sickness and disorientation during VR training sessions. To prevent this from occurring, future systems must incorporate adaptive algorithms that adjust visual flow and scene complexity based on patient feedback. Improved hardware with higher refresh rates and ergonomic designs may also mitigate these adverse effects. Other limitations include the high initial costs and overall level of resources that are required. This is especially salient for fully immersive systems that are not readily available in all clinical settings. Finally, standardization between systems and protocols remains limited, which makes comparing outcomes and generalizing findings more difficult. Future implementation of these systems will therefore hinge on further evidence-based development of protocols and establishing consensus guidelines through larger trials.

Conclusions

VR has rapidly emerged as a multifaceted tool in neurorehabilitation, offering an immersive, adaptable, and engaging platform that can help promote neuroplasticity and functional recovery. Its mechanistic foundations—rooted in multisensory stimulation, mirror neuron activation, and adaptive feedback—can help enable robust improvements in motor and cognitive functions. With modalities ranging from fully immersive systems to more cost-effective augmented reality solutions, VR can be tailored to meet the diverse needs of neurocritical care patients recovering from a variety of acute and progressive neurological diseases. Although challenges such as cybersickness, high costs, and a lack of standardized protocols remain, emerging solutions and ongoing research have the potential to help overcome these barriers. Looking forward, the integration of VR with brain-computer interfaces (BCIs), AI-driven personalization, and telemedicine could further enhance its clinical utility, making VR a potentially indispensable component of neurorehabilitation in the future.