# A Wearable Sonification System to Improve Movement Awareness: A Feasibility Study
## 2 Related Work
The authors investigated the effects of concurrent versus delayed auditory feedback and found that concurrent auditory feedback was beneficial compared to delayed auditory feedback. The delayed auditory feedback led to significant distractions and irritations, significantly affecting the participants' movement performance. Similarly, a recent study by [PERSON] et al. [15] has investigated sonification through manipulating acoustic features (e.g., pitch, timbre, amplitude, tempo, duration, and spatialization) and their potential to influence gait rehabilitation. They found that manipulating acoustic feedback played a vital role in user engagement and enhanced therapeutic outcomes. The complexities of auditory feedback's impact on motor tasks have been highlighted, suggesting it can both aid and impair motor execution depending on the sound parameters such as timing [30], volume [31], pitch [17], and continuous or discrete [45, 46, 47]. Discrete auditory feedback (DAF) has been used extensively to cue and time walking gait via metronomic or musical beats, and is commonly referred to as Rhythmic Auditory Stimulation (RAS) [47,48]. [PERSON] et al. [47] suggested that cueing the step in a walking gait with a beat or a metronome as DAF may not be adequate for sonifying the continuous gait state. Between these beats were intervals that could be further sonified to express the richness of the change in the swing of the legs between these footsteps. Continuous auditory feedback (CAF) provides information on the unfolding and continuous state of movement. CAF appears promising to help and guide people to perform a specific movement consistently, which may avoid any potential injury, improve the quality of their movement, or potentially regain normal function for those with movement disorders [45,49,50]. CAF can reduce participants' delays in tracking screen-based targets with manually operated joystick and Wacom pen input devices [51]. One plausible explanation would be that CAF eases participants in continuously estimating and correcting on-screen targets' trajectories between their start and end points, thus leading to better tracking accuracy [46]. Although previous studies have contributed to our understanding of the effects of auditory feedback, research is needed into personalized auditory feedback systems that account for individual variability in gait and rehabilitation responses. Further exploration into integrating auditory cues as a form of feedback mechanism in wearables could also enhance user experience and outcomes. Therefore, this study aims to design, develop, and feasibility test an auditory feedback system prototype for balance training. Balancing is informed via discrete bell-like tones combined with continuous tones that are directly modulated via the rotation of the torso to adjust their brightness. These two auditory mechanisms aim to signal users when they move away from their center of mass (CoM) to aid in balance correction. In this study, we sought to address the following research questions (RQ):  
1. RQ1: Is a low-cost IMU device attached to the torso an effective means of generating data to provide auditory feedback for balance correction?RQ2: Do continuous and discrete tones generated from balance rotation movements aid in correcting balance back to a desired reference region?