## 1 Introduction
For instance, a systematic review of 15 studies investigating the impact of music therapy on AD patients showed significant  
Figure 1: The Alzheimer’s continuum, showing the progression from preclinical stages to severe dementia, with an increasing severity of cognitive and functional decline across distinct stages of the disease. Modified from [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] [6]. improvements in cognitive abilities and daily living activities [14]. Another systematic review and meta-analysis also implied that non-pharmacological therapies, including music therapy, positively impacted activities of daily living (ADLs), behavioral and psychological symptoms of dementia (BPSDs), cognition, and quality of life in individuals with moderate-to-severe dementia [15]. Furthermore, music therapy alone was shown to significantly enhance both cognitive function and quality of life in subjects with AD [16]. Such evidence highlights the need to include these non-pharmacological interventions in treatment plans; in fact, by integrating both pharmacological and non-pharmacological approaches, patient outcomes can be best optimized on a multimodal basis by addressing both the cognitive as well as emotional deficits of AD. Emerging technologies like virtual reality (VR) hold much potential in the treatment of both MCI and AD. Offering the presentation of immersive, simulated environments that can engage cognitive and emotional processes, VR can be considered a suitable technological framework to address the challenges associated with MCI and early AD [17; 18]. The recent literature provides evidence supporting the efficacy of VR interventions in this context. For example, [PERSON] et al. [19] introduced the positive impact of VR on cognitive function for MCI subjects, also impacting daily living activities and neuropsychiatric symptoms, highlighting its potential as a tool for cognitive rehabilitation. Furthermore, [PERSON] et al. [20] investigated the effects of dual-task interventions in individuals with MCI, combining motor and VR-based cognitive training, reporting enhanced executive function and gait performance. Very recently, [PERSON] et al. [21] conducted a meta-analysis of 18 randomized controlled trials conducted with VR interventions on MCI patients (722 participants were included), demonstrating significant improvements in cognitive functions among older adults with MCI compared to control groups. The effect sizes reported included a Standardized Mean Difference (SMD) of 0.20 (95% CI: 0.02-0.38) for memory, 0.25 (95% CI: 0.06-0.45) for attention and information-processing speed, and 0.22 (95% CI: 0.02-0.42) for executive functions, indicating small to moderate improvements in these cognitive domains. Many of these scenarios included soundscapes, such as ambient environmental sounds like birdsong or flowing water, or music tailored to enhance relaxation and engagement. Additionally, VR has been used for dual-task exercises that combine cognitive challenges with motor activities, such as navigating virtual pathways or interacting with objects within the virtual space [17; 18; 19]. These findings emphasize the potential of VR as a therapeutic tool for mitigating cognitive decline and improving the quality of life in individuals with MCI and early AD. At the same time, the scarcity of applications of VR for early AD compared to MCI, as well as the high costs of devices and the need for multiple sessions, highlight significant challenges to its accessibility and feasibility for long-term AD treatment. This underscores the need for implementing novel methodologies that are both cost- and time-effective, paving the way for more sustainable and widely applicable interventions. In addition to the outcome-based results, it is important to consider the possible effectiveness of VR interventions on age-related cognitive and motor decline. VR provides optimal stimulation through multisensory access within digital worlds that can also promote the cognitive functions of memory and executive control.