## 1 Introduction  
Human postural control, a complex process involving the integration of multiple sensory systems, relies on the coordinated functioning of visual, somatosensory, and vestibular systems [1]. Among these, the auditory system plays a critical role in maintaining postural balance by activating brain regions associated with cognitive processes and contributing to overall stability [2, 3]. The relationship between the vestibular system and the organ of Corti highlights the significant impact of auditory stimuli on postural balance [3]. This study investigates the influence of auditory environments, including natural sounds and noise, on postural balance. While prior research has explored the connection between auditory environments and mood or well-being in individuals with intellectual disabilities [4, 5], the direct impact of auditory stimuli on postural balance, particularly under dual-task conditions, remains unclear. Evidence from studies on typically developing individuals suggests that nature sounds may enhance postural balance [6], whereas noise has been linked to degraded postural balance [3], while intermittent white noise has yielded varied outcomes, ranging from negligible [7] to positive [8] effects. These mixed findings underscore the need to clarify how different auditory stimuli impact postural control. Auditory environments also affect cognitive performance. Nature sounds have been linked to cognitive improvements, stress reduction, and attention restoration [9; 10; 11; 12]. In contrast, prolonged noise exposure has been associated with cognitive impairment and oxidative stress [13; 14; 15]. Interestingly, certain noise types, such as white noise, have demonstrated benefits for sustained attention and working memory [16; 17]. Despite this knowledge, limited research has addressed the combined effects of auditory environments on postural balance and cognitive performance during dual-task conditions, which reflect real-world challenges. The dual-task paradigm involves the simultaneous coordination of motor actions and cognitive processes [18]. This paradigm has played a crucial role in revealing weaknesses in postural balance when individuals engage in competing cognitive tasks. Such declines have been observed across various populations, including healthy individuals, stroke survivors, older adults, and individuals with Parkinson's disease [19; 20; 21; 22]. For individuals with intellectual disabilities who are already predisposed to challenges in postural balance [23; 24] and cognitive functions [25], dual-task conditions present unique and compounded difficulties [26; 27]. Postural disturbances in this population are often linked to deficits in visual processing, proprioception, and vestibular function [28]. Additionally, dysfunctions in the central nervous system (CNS) have been identified as significant contributors to these disturbances [28]. Cognitive impairments in individuals with intellectual disabilities, commonly associated with low intelligence quotient scores (below 70) [29] and limitations in attention, memory, and executive function [30], further complicate the ability of individuals with intellectual disabilities to effectively allocate attention during dual-task situations. These challenges can exacerbate postural instability in such scenarios [31; 32; 33; 34]. Notably, the auditory environment could play a significant role in how individuals with intellectual disabilities respond to these dual-task situations. Understanding the interaction between auditory environments and dual-task conditions is critical for designing interventions to improve daily functioning, mobility, and safety in individuals with intellectual disabilities. This study aims to examine how different auditory environments, specifically natural sounds and noise, affect postural balance in this population under dual-task conditions. By exploring these interactions, we aim to clarify the interplay among sensory, motor, and cognitive processes.