Improving detectability of auditory interfaces for medical alarms through temporal variation in amplitude envelope

BACKGROUND: Auditory interfaces play a vital role in many applications, informing users about both urgent and routine information critical to safety. Unfortunately, problems related to high alarm rates, low reliability, and sound annoyance create barriers to optimising the quality of patient care in perioperative medicine and critical care. Here, we explore how to reduce annoyance and improve detection by manipulating a sound's temporal envelope or the way its energy changes over time. METHODS: In the first experiment, participants were asked to detect a series of percussive and flat tones presented at six signal-to-noise ratios while performing a concurrent speech comprehension task. In the second experiment, different participants were asked to evaluate the relative annoyance of these same sounds. RESULTS: Relative to industry-standard flat tones, percussive tones were significantly less annoying and more detectable. Although more detectable, percussive tones did not impair concurrent speech comprehension. CONCLUSIONS: Temporal variation in amplitude envelope represents a promising path towards improving auditory interfaces for patient monitoring. By using temporally variable sounds, auditory interfaces can be more effective in alerting users. This is important for safety-critical areas, such as medical alarms, where annoyance often limits efficacy. As this manipulation can preserve the pitch and rhythm of tone sequences, it is compatible with users' pre-existing knowledge of current alarms.