Briefly walk us through the research methods that you used to ensure that the AngelMed Guardian’s vibratory alarms were easy to distinguish.
I conducted several experimental studies. The first of these was designed to identify the best temporal characteristics for the vibratory alarms and to ensure that the magnitude of the vibration was appropriate. In these studies, participants were presented with Emergency alarms and See Doctor alerts with different temporal characteristics (that is, different pulse durations and interpulse intervals) and with alarms of different strengths. Participants provided
multiple ratings and judgments, such as strength ratings, strength preferences, urgency ratings, and temporal pattern preferences.
In one of the studies, I also compared two different auditory alarm frequencies. It was exciting to find that similar characteristics affect perceived urgency for both vibratory and auditory alarms. Data from these studies were used to define temporal characteristics for the two alarm types. I then conducted a learning and
memory study, in which participants were trained on the alarms in the same way that a patient would be trained. Accuracy of alarm identification was then assessed about 10 minutes after training and then six weeks after training.
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Mary Carol Day is director of User Interface Systems at Angel Medical Systems. Previously she was president of M. C. Day Consulting and a technical manager at AT&T Bell Laboratories. She is a Fellow of HFES and a voting member of the AAMI Human Factors Engineering Standards Committee.