Decaying amplitude envelopes reduce alarm annoyance: Exploring new approaches to improving auditory interfaces

Noise, Distractions, and Hazards in the Operating Room

Anesthesiologists are perioperative leaders of patient and health care team safety. The anesthesiologist needs to remain vigilant in the perioperative setting and while caring for patients. The ability to navigate increased noise levels, distractions, and hazards is crucial for maintaining a safe environment. While some noise, such as music, can have benefits, overall noise levels can distract from patient care and have adverse effects on patient care and intraoperative staff. This study provides an overview of noise, distractions, and hazards in the perioperative environment.

Ten Years Later, Alarm Fatigue Is Still a Safety Concern

Ten years after the publication of a landmark article in AACN Advanced Critical Care, alarm fatigue continues to be an issue that researchers, clinicians, and organizations aim to remediate. Alarm fatigue contributes to missed alarms and medical errors that result in patient death, increased clinical workload and burnout, and interference with patient recovery. Led by the American Association of Critical-Care Nurses, national patient safety organizations continue to prioritize efforts to battle alarm fatigue and have proposed alarm management strategies to mitigate the effects of alarm fatigue. Similarly, clinical efforts now use simulation studies, individualized alarm thresholds, and interdisciplinary teams to optimize alarm use. Finally, engineering research efforts have innovated the standard alarm to convey information more effectively for medical users. By focusing on patient and provider safety, clinical workflow, and alarm technology, efforts to reduce alarm fatigue over the past 10 years have been grounded in an evidence-based and personnel-focused approach.

Incremental advances will improve medical device alarm sounds

The March issue contains a laboratory study of auditory perception, which is an unusual topic for this journal. A perspective is provided on how the study relates to recent research on clinical auditory alarms and displays. Techniques used in the study are explored and explained, such as enrolment of non-clinician volunteer participants, use of coordinate response measure phrase stimuli, presentation of sound loudness levels using the decibel scale, and analysis using signal detection theory. Such efforts to improve the safety, efficacy, and tolerability of modern medical device alarms are critical for improved patient safety.

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.

More detectable, less annoying: Temporal variation in amplitude envelope and spectral content improves auditory interface efficacy

Auditory interfaces, such as auditory alarms, are useful tools for human computer interaction. Unfortunately, poor detectability and annoyance inhibit the efficacy of many interface sounds. Here, it is shown in two ways how moving beyond the traditional simplistic temporal structures of normative interface sounds can significantly improve auditory interface efficacy. First, participants rated tones with percussive amplitude envelopes as significantly less annoying than tones with flat amplitude envelopes. Crucially, this annoyance reduction did not come with a detection cost as percussive tones were detected more often than flat tones-particularly, at relatively low listening levels. Second, it was found that reductions in the duration of a tone's harmonics significantly lowered its annoyance without a commensurate reduction in detection. Together, these findings help inform our theoretical understanding of detection and annoyance of sound. In addition, they offer promising original design considerations for auditory interfaces.