Sufficient for annoyance, yet unnecessary for detection. Improving alarm design by embracing temporal variability.

Sufficient for annoyance, yet unnecessary for detection. Improving alarm design by embracing temporal variability.

Presenter Name:Liam Foley

School/Affiliation:McMaster University

Co-Authors:Michael Schutz

Abstract:Auditory notifications, such as auditory alarms, are ubiquitous in our modern lives. However in areas such as medical devices alarms are plagued with problems including high alarm rates, masking, confusion, and annoyance. Currently, alarm standards dictate high alarm volumes in an effort to ensure detectability which unfortunately contributes to an auditory cacophony felt by both patients and health practitioners. The role of temporally variable harmonic energy remains under explored in this space, and research from our team suggests it holds potential for improving alarm efficacy in high-stress environments. In this project, we explore the effects of tone detection, amongst noise and temporally varying harmonics. Tones consisted of a 600ms or 360ms 400 Hz fundamental with five harmonics at (800 Hz, 1200 Hz, 1600 Hz, 2000 Hz & 2400 Hz) with five versions of overtone duration relative to the harmonic; 100%, 50%, 25%, 10%, 5%, and two amplitude envelope conditions; flat or percussive. We found alarm signals with temporally varying structures to be significantly less annoying than alarms with traditional, temporally invariant structures.  We also found tones with shorter durations of harmonic structures to be generally less annoying.  Curiously, neither of these manipulations (increasing temporal variation, decreasing harmonic duration) affected detectability.  Together, these findings suggest more temporally complex alarms could offer meaningful improvements in alarm design by improving their ergonomics while preserving their communicative efficacy.

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