auditory alarms

Despite the fact that auditory alarms are designed to grab attention, alarms in a hospital setting can be ineffective and have resulted in several deaths and injuries annually. In fact, several studies indicate that medical staff are unable to identify half of the alarms they encounter on a daily basis (Edworthy & Hellier, 2006).

We suspect that poor learning, retention and confusions among medical alarms can be attributed, in part, to the types of sounds being used. Currently we are investigating ways to improve auditory alarms on several acoustic parameters (a) using amplitude envelope as a cue for communication, (b) the role of tonal structure note-to-note and (c) the importance of varying parameters for the sake of heterogeneity among alarms within a set.

Our first published study explored the effects of melodic structure on alarm confusions. Confusions often appear related to similarities in the alarm’s melodic structure – an aspect of alarms not often considered in their design.

In the figure (taken from Gillard & Schutz, 2016), thicker exterior indicate greater numbers of confusions. For example, the alarm indicating cardiovascular issues was often confused with the alarm designed to warn of temperature issues. Both the perfusion and infusion alarms were mistaken for the ventilation alarms at relatively high rates. Analysis of the melodic properties of these frequently confused alarms indicates that similarities in their intervallic content may explain some confusions. This finding helps demonstrate how basic principles of music perception could help contribute to improvements in the efficacy of auditory alarms in medical devices.

For full details and analyses download the paper from our publications page.