Emerging Technologies in Assistive Devices: Shaping the Future of Rehabilitation Engineering

2.1 Short history of virtual reality

The history of virtual reality (VR) is indeed an exciting one and reflects a constant evolution of technology and human imagination. As early as the 1930s, the concept of VR began to be explored in literature, and later, the first practical attempts to bring the idea to reality [1]. An early reference point is the story “Pygmalion’s Spectacles” by Stanley G. Weinbaum, published in 1935. It described a device capable of providing users with immersive sensory experiences, anticipating in a visionary way the fundamental elements of VR: visual, auditory, and narrative simulation. This story laid the foundations for the idea of VR, even if the term itself was used much later [2].

Another key moment in the evolution of VR came in 1957 with the invention of the “Sensorama” by Morton Heilig. This device was a true technological breakthrough, providing users with visual, auditory, olfactory, and tactile sensations to simulate realistic experiences. Although “Sensorama” was not conceived as a wearable device, it was the forerunner of modern VR technologies and demonstrated for the first time the immersive potential of this technology [3, 4]. These defining moments demonstrate that, from its inception, VR was seen to extend human perception and transform interaction with the environment. The continued exploration and development of technology has opened numerous possibilities in areas such as entertainment, medicine, education, and scientific research.

Ivan Es. Sutherland is absolutely a towering determine withinside the records of technology, being taken into consideration the “figure of pics for your computer. In 1965, he supplied an innovative imaginative and prescient of VR, describing the concept of a „display screen that suggests a really perfect international” and laying the conceptual foundations of VR. This description, known as “The Ultimate Display,” predicted a computer-generated international that could not simply be seen, but was additionally skilled as tangible. The fruits of his paintings turned into a reality in 1968, while he created the primary practical VR tool, known as the Sword of Damocles. It consisted of a head-installed show related to a head-monitoring system, giving the person the feeling of immersion in a three-dimensional, computer-generated space. Although the tool turned into rudimentary, with a cumbersome layout suspended from the ceiling (for this reason, its symbolic name), it marked the start of a brand-new generation for immersive technologies. “Sword of Damocles” turned into a key second within the evolution of VR, introducing standards that are nevertheless used today, including monitoring the placement and actions of the person to modify the visible perspective. The basis for advanced development was set at some stage in this early stage, which performed a substantial position within the established order of VR as a studies discipline with a number of applications, including schooling simulations, scientific therapies, and entertainment [5].

In 1991, Jaron Lanier and Thomas G. Zimmerman, two influential figures in technology, founded The Virtual Reality Foundation, marking a pivotal moment in VR history. Lanier, credited with coining the term “virtual reality” and pioneering the development of early VR equipment, played a key role in shaping both the technological and conceptual framework of the field. Alongside Zimmerman, he championed the integration of VR across various industries, including education, medicine, and entertainment. One of the foundation’s greatest achievements was establishing a collaborative platform for researchers, engineers, and entrepreneurs, fostering a global ecosystem of VR innovation. Their efforts not only drove technological advancements but also made VR equipment more affordable, accelerating its widespread adoption [6, 7, 8].

The 1990s were a milestone in the popularization of VR technology, marking the debut of modern consumer VR devices. It was during this period that companies such as Sega and Nintendo took the first steps in bringing VR to the mass market, offering products that promised immersive experiences. A notable example is Virtual Boy, which was launched by Nintendo in 1995. It was the first significant attempt to bring VR into consumers’ homes through an affordable device. Virtual Boy used a monochromatic system based on red LEDs to create stereoscopic 3D images, giving users a sense of depth while playing. In parallel, Sega has been developing prototypes for devices such as Sega VR, which are designed for its game consoles. In addition, the trials in the 1990s demonstrated that VR had the potential to become more than a niche technology, foreshadowing its expansion into areas as diverse as gaming, education, and medicine [9].

After 2010, VR experienced a renaissance thanks to advances in mobile technology, the increased processing power of computers, and the miniaturization of electronic components. These advances have made it possible to develop affordable, high-performance, and easier-to-use VR devices, allowing consumers to experience VR in the comfort of their own homes. Companies such as Oculus, HTC, and Sony have played a significant role in this technological revolution. The launch of the Oculus Rift headset in 2016, which began as a Kickstarter project, marked a milestone in the VR industry. With an ergonomic design, precise motion tracking, and high graphics quality, the Oculus Rift redefined the standard for high-quality VR experiences. HTC, in partnership with Valve, launched the HTC Vive, another innovative device that introduced full 3D spatial tracking through intuitive base stations and controllers, bringing more natural and immersive interaction. At the same time, Sony entered the VR market in a big way with PlayStation VR for PlayStation 4 consoles, making VR technology accessible to a wide audience of gamers [4, 10, 11, 12].

The advancement of VR technology has generated other related technologies that extend and enrich the interaction between users and their environment, such as augmented reality (AR) and mixed reality (MR). These concepts have redefined the way we perceive and interact with the real world, adding new digital layers of information and experiences. AR, which superimposes virtual elements (images, sounds, or data) over the real world, has become known to the public through devices such as Google Glass. Despite being initially aimed at ordinary consumers, the project has since become useful in specialized fields like medicine, industry, and education. Mixed Reality (MR) is a combination of VR and AR that creates dynamic interactions between virtual and real objects. It was popularized by Microsoft through the HoloLens. HoloLens devices can make it possible to integrate digital objects into the physical world and interact with them in a natural way, which can be applied to design, architecture, surgery, and professional training [13, 14].

VR is now recognized as an advanced technology that enables users to interact with simulated environments in either two-dimensional (2D) or three-dimensional (3D) formats through specialized devices. The most common of these are VR headsets, which are worn on the head to create an immersive virtual experience. Users can use resolute controllers or joysticks to interact with these environments, allowing them to manipulate objects and navigate smoothly. To provide a VR experience that is responsive and intuitive, these devices are necessary, allowing for real-time feedback and precise control over movements in virtual space [15, 16]. Virtual reality applications are diverse and are expanding in various industries, including:

• Gaming – VR has transformed the gaming industry, offering an immersive experience that is unmatched in comparison to traditional games.

• Education and training – VR can be used in education and training to recreate real-world scenarios, such as surgical procedures or military exercises, using interactive learning simulations.

• Medicine – VR plays a role in rehabilitation therapies, medical procedure simulations, and even the diagnosis and treatment of certain conditions.

• Architecture and design – Professionals can develop and visualize 3D models of structures, enabling them to explore and refine designs before physical construction begins.

• Tourism – Virtual tours allow users to explore destinations remotely, providing a realistic experience of travel without leaving home (Figure 1).

VR is based on creating an artificial world where users can interact similarly to the real world, but in virtual environments. This is achieved through a human-computer connection, which allows for a detailed simulation of virtual environments and deep interaction with them. In this way, VR combines advanced computing technology with sensors that allow the perception of visual, auditory, tactile, and kinesthetic stimuli, providing a highly immersive experience [17]. Simulation, interaction, and immersion are the essential elements on which VR technology is based. Simulation refers to the creation of a virtual environment that mimics reality or creates a completely new universe, while interaction is achieved through devices that allow users to manipulate objects, navigate, or communicate with elements in the virtual world. Immersion refers to the ability of technology to “lock” the user into a virtual environment, making them feel part of that environment. These elements enable intuitive interaction, where the user perceives stimuli in the virtual world through various senses, helping to make a deep emotional and cognitive connection with the virtual environment [18]. For example, visual and auditory stimuli create a sense of presence, while tactile and kinesthetic stimuli, through haptic devices, add a physical dimension to the experience. One of the significant advantages of VR is the ability to reduce the perception of pain and transform unpleasant experiences into more comfortable virtual environments. This is possible by connecting the cognitive and emotional centres of the nervous system, which are positively influenced by virtual stimuli. VR can be used for therapeutic purposes, for example, in pain management or rehabilitation to help patients cope with difficult or painful situations in a more controlled and comfortable way [19].

2.2 Virtual reality and rehabilitation engineering devices

The use of VR in rehabilitation is indeed gaining ground, supported by a growing body of scientific evidence highlighting its diverse applications. VR has shown promise in the rehabilitation of upper limb function after stroke. By using virtual environments that ask patients to perform specific motor tasks, VR can help improve movement coordination, motor learning, and neuroplasticity. Several studies have demonstrated significant improvements in functional outcomes for stroke patients using VR-assisted rehabilitation. VR interventions have applications in musculoskeletal rehabilitation such as joint and soft tissue injuries, post-surgical recovery, or chronic pain management. The immersive nature of VR helps to promote active engagement, improve joint mobility, and encourage repetitive exercise in a controlled and motivating environment [20].

A virtual reality (VR) system is a combination of hardware and software components that work together to create an immersive digital experience. The hardware component includes a VR headset (HMD—Head-Mounted Display) for stereoscopic images and head tracking, motion controllers for interaction, and external sensors such as cameras, infrared trackers, or LiDAR for precise motion detection [21]. A processing unit (PC, game console, or standalone VR system) powers the experience by rendering graphics and handling calculations. Haptic feedback devices, including gloves, vests, or full-body suits, simulate the sensations of touch, while a spatial audio system enhances immersion. The software component includes a VR engine (such as Unity or Unreal Engine) to create and render 3D environments, while tracking software processes motion data from the sensors. Middleware and SDKs (such as OpenVR, Oculus SDK, or SteamVR) provide APIs for hardware compatibility, and the operating system (Windows, macOS, Android) supports applications and drivers. VR applications and games provide interactive experiences, from entertainment to professional simulations, while cloud or network services enable multiplayer functionality, data synchronization, and content streaming (Figure 2).

Several different commercially available VR and MR devices are being used in rehabilitation. Each device is associated with a leading company in the field and offers a wide range of solutions for treatments in various medical conditions, such as neurological disorders, post-stroke recovery, and others, to improve motor and cognitive function, as well as mental health treatments [22]. Table 1 devices are novel devices that enable patients to actively engage with virtual environments to enhance their physical and emotional recovery. The integration of interactive therapies into hospitals and rehabilitation centres requires these technologies, which promote a more personalized and effective approach to the healing process.

2.3 Essential elements of virtual reality

VR is an advanced technology that creates interactive environments and experiences using a computerized system. These environments are digitally generated and allow the user to interact with them, creating a sense of deep immersion and physical presence in virtual worlds. VR devices, such as specially designed headsets and goggles, are used to simulate experiences and transport the user into an artificial reality, often different from the real world. By using these technologies, VR can stimulate the user’s visual, auditory, and tactile senses, providing a sense of “being present” in the virtual environment, which can be perceived as real, even if it is artificially constructed. Its wide applicability has made VR integrated into numerous domains such as entertainment, education, health, architecture, and many others, revolutionizing the way people interact with technology and the environment [38, 39, 40, 41].

Understanding VR technology involves exploring how it creates and manages immersive virtual environments. These environments are built entirely digitally, using special computers and software that allow the generation of realistic or completely imaginary 3D worlds. From detailed representations of the environment to fantasy worlds, VR offers a wide range of possibilities for creating immersive experiences. A key aspect of this technology is graphical representation, which focuses on details such as lighting and textures, which are fundamental to creating a plausible and realistic virtual environment. Visual details help amplify the sense of presence in the virtual world, thus contributing to an immersive and authentic experience for the user [42, 43, 44].

Immersion in VR is the sensation of being physically present in a fully digital environment, achieved by creating holographic experiences that make the user forget about the real environment during interaction. An essential element of immersion is the user’s interaction with devices that monitor body movements and translate them into the virtual environment. These devices, such as VR goggles or specialized gloves, allow natural and fluid interaction with the holographic environment, enhancing the feeling of physical presence and intensifying immersion. Thus, the user feels as if they are part of the virtual world, not just an observer [45, 46, 47]. Real-time interaction is a fundamental aspect of VR, allowing the user to interact directly and immediately with the virtual environment. This is achieved by manipulating objects, communicating with characters in the digital world, and actively influencing the environment. Two-way interactions are essential to create an authentic and immersive experience. In addition, to enhance the immersion and reality of these interactions, many VR devices include haptic feedback, which provides tactile sensations through vibrations, simulating touching and manipulating objects. These technologies contribute to a more natural and interactive user experience, more closely approximating physical reality [48, 49].

The simulation and representation of 3D objects are essential in creating virtual environments, using advanced 3D modeling techniques to generate objects, characters, and landscapes that can range from realistic to fantastic. These objects are integrated into a digital environment that respects the principles of physics, such as gravity, collisions, or fluid interactions, to provide a more authentic and immersive experience. Physical simulation plays a crucial role in the realism of VR environments, as it helps to create an accurate perception of the behavior of objects in the virtual world, thus contributing to the immersion and interaction of users with these worlds (Figure 3) [50, 51].

Sensors and motion tracking are crucial for interpreting and replicating user movements in a virtual environment. VR devices use a combination of technologies, including tracking cameras, gyroscopes, and accelerometer sensors, to recognize body gestures and movements. The use of these technologies allows users to control the holographic environment with the help of their hands or bodies, resulting in a more natural and intuitive interaction. The use of motion tracking technologies is crucial to ensuring an immersive and realistic experience and creating a sense of presence in the virtual world [52, 53, 54].

The future of virtual reality in rehabilitation engineering is being driven by VR’s therapeutic benefits, technology advancements, and interdisciplinary research. The use of wearable sensors and biofeedback devices will make it possible for VR systems to regulate therapy intensity, duration, and focus according to physiological responses such as heart rate, muscle activity, and neural feedback. VR’s ability to stimulate multiple senses simultaneously allows it to stimulate neural pathways and help with recovery from strokes, traumatic brain injuries, and neurodegenerative conditions.

3.1 Applications of AI in mobility assistive devices: Exoskeletons

Artificial Intelligence (AI) is a notable change in the design, functionality, and usability of exoskeletons. The integration of AI has resulted in exoskeletons becoming smarter, more adaptive, and capable of significantly improving mobility, strength, and rehabilitation outcomes. Exoskeletons are wearable robotic systems that provide mechanical support and assistance to individuals with physical impairments, aiding in mobility, rehabilitation, and performance enhancement. AI-driven advancements make these devices smarter and more effective by integrating real-time adaptability and user-centric customization. The essential capacities of individualities can be enhanced to a significantly lesser extent by exercising an external frame appertained to as an exoskeleton. It also aids in mending damage sustained. A lower branch exoskeleton assists individuals who struggle to conduct their daily tasks. They grease walking and performing with the help of electric motors. The upper branch exoskeleton is a device that can be moved and attached to the arm. Commands to operate the device are handed by the stoner [59]. The category of lively exoskeletons is decided through their presence of motors, at the same time as unresistant bones are diagnosed through their absence of motors. The chance of musculoskeletal accidents may be minimized while lifting heavy details with a powered or lively exoskeleton. The use of passive exoskeletons is meant to help objects, offer ergonomic help, and help with accidents. The layout of quasi-passive exoskeletons is to help masses at the same time as strolling and consists of a knee variable mute, alongside hip and ankle springs [60].

AI in lower limb exoskeleton rehabilitation improves mobility and recovery, allowing for adaptive, personalized treatment. By analyzing data in real time, AI optimizes the exoskeleton’s movements to match the user’s intent, adapts rehabilitation plans and provides continuous feedback. It supports motor relearning, improves safety, and accelerates recovery by predicting progress and adjusting support levels accordingly (Figure 5). This integration helps people with mobility impairments regain their movement more efficiently and effectively [61].

AI features in exoskeleton devices are:

• Adaptive control systems: AI methods sensor records along with motion, muscle activity, and stress to make real-time modifications to exoskeleton movements. This lets in for adaptive gait styles that assist customers to stroll naturally, even in dynamic environments.

• Personalized machine learning: AI continuously learns from the user’s biomechanics and behavior, fine-tuning the exoskeleton to meet individual needs. Over time, it enhances key aspects like speed, balance, and endurance.

• Rehabilitation assistance: AI-powered exoskeletons aid physiotherapy via way of means of guiding unique movements, making sure right posture, and handing over real-time comments to therapists.

• Environmental awareness: AI-pushed sensors locate obstacles, terrain variations, and different environmental factors. The gadget adjusts therefore to one-of-a-kind surfaces, which include stairs, slopes, and choppy ground, to enhance safety.

• Brain-computer interfaces (BCIs): Advanced AI translates neural alerts from BCIs, permitting customers to manipulate the exoskeleton via thought. This is specifically useful for people with intense mobility impairments, together with spinal twine injuries.

• Optimized energy efficiency: AI complements electricity control with the aid of using predicting movement styles and directing electricity in which it is far wished most, maximizing efficiency [62].

3.2 Application of cognitive assistive devices

Cognitive assistive devices are advanced technologies designed to aid individuals with cognitive impairments, such as memory loss, attention deficits, or executive function challenges. These devices utilize innovative technologies, including artificial intelligence (AI), to help users manage daily activities, enhance independence, and improve their overall quality of life [63]. AI-powered algorithms enable these devices to anticipate user needs and provide personalized support in conjunction with advanced sensors. For instance, portable electroencephalograms (EEGs) monitor brain activity, while biometric sensors track stress levels, attention, and heart rate. Ongoing research also explores neural implants—systems that stimulate specific brain regions to enhance cognitive functions.

Application of cognitive assistive devices:

Medicine and rehabilitation: support for patients with neurodegenerative diseases (e.g. Alzheimer’s and Parkinson’s), cognitive rehabilitation after strokes or head injuries or devices for managing anxiety, depression, or ADHD.

Education: personalized learning systems that analyze students’ cognitive styles or apps that support people with learning disabilities (e.g. dyslexia).

Support in daily activities: electronic organizers that provide reminders or help with planning activities.

Social integration: real-time translation systems for sign language or assisted speech. Technologies that help people with autism spectrum disorders interpret facial expressions and tone of voice [64].

The future of artificial intelligence (AI) is poised to revolutionize assistive devices engineering, making them more adaptive, intuitive, and accessible. With advancements in AI technologies and their integration into assistive devices, the future holds transformative possibilities for individuals with physical, cognitive, and sensory impairments. AI systems will continuously refine their responses based on user interactions and real-time data, ensuring optimal support [65].