## 1 Introduction  
Multiple sclerosis (MS) is a well-known, chronic, disabling, and progressive pathology diagnosed in approximately 2.8 million people worldwide [1]. MS is among the top causes of disability when we refer to young people, with an estimated incidence ranging from 1.1 to 4 per 100,000 people globally [2]. The disease is characterized by an autoimmune, inflammatory, and demyelinating process that affects the brain and spinal cord. This process leads to progressive loss of neurons and axons. Symptoms vary depending on the location of the lesion [3]. Gait disorders such as reduced speed and stride length, gait asymmetry, and balance disorders are disabling aspects of people living with MS. The risk of falling among these patients results in a low quality of life and reduced independence in activities of daily living (ADL) [4]. Therefore, improving walking ability is a main objective for rehabilitation. Various studies carried out for the rehabilitation of patients with central motor neuron disease have shown that classic rehabilitation programs based on physical therapy [5] and physiotherapy can have very good results on spasticity [6] and can improve motor function and even walking ability, therefore improving autonomy [7]. In addition to traditional physiotherapy and rehabilitation techniques, the use of various new technologies presents a promising way to achieve a comprehensive treatment of MS [8]. Among these innovations, virtual reality (VR) methods have already emerged as potentially valuable tools for addressing various neurorehabilitation challenges [9]. VR can be successfully utilized as a standalone treatment method as well as in conjunction with other technologies [10; 11]. VR facilitates interaction within a simulated environment closely resembling the real world, offering multisensory feedback training that could enhance rehabilitation outcomes. Human balance control relies on integrating inputs from multiple sensory systems, including visual, vestibular, and proprioceptive signals, into a complex mechanism of continual adjustment and recalibration [12]. Consequently, incorporating multisensory augmented reality techniques may prove particularly effective in addressing balance impairments associated with MS [10]. Studies using VR in adults with MS have highlighted the existence of possible benefits. Although these patients present numerous symptoms, the latest systematic reviews about the use of VR in people with MS focus only on the rehabilitation of symptoms such as balance and gait disorders [13]. Although gait rehabilitation cannot be separated from balance disorder rehabilitation [14], this review focuses primarily on observing the relationship between VR and the rehabilitation of balance disorders in patients with MS. However, it also aims to investigate the effects that VR may have on other symptoms of multiple sclerosis. This is one of the reasons why we have not limited our research to a specific type of virtual reality. The beneficial effect of using VR in different ways is well known, whether we are talking about the results of exergaming in several rehabilitation programs with promising results [15; 16], or robotic technology that is used in association or not with VR [17; 18]. Various virtual reality programs have been implemented both in clinical settings and at home for gait and balance retraining, aiming to increase adherence to rehabilitation treatment. The use of VR technology has attracted even more attention following the COVID-19 pandemic, which has affected both medical professionals [19] and patients by limiting access to rehabilitation services and diminishing the results they have already achieved [6]. The results remain controversial [20]. These are some reasons to pursue the objectives of the present study, mainly to summarize the evidence of VR interventions in recent years for the rehabilitation of balance and gait in patients with multiple sclerosis and, secondarily, to determine the effects of VR on other symptoms of MS.