Auditory Alarms Research Articles

Evaluation of tactile cues for simulated patients’ status under high and low workload

The intensive care unit (ICU) is one of the most complex areas in hospital care, as patients require continuous monitoring by physicians and nurses. Currently, clinicians are informed about the patients’ physiological conditions through visual color-coded signals and auditory alarms. Previous studies have shown that vibrotactile cues can be used to inform clinicians of a patient’s vital signs status, either in a unisensory or multisensory alarm scheme. We present the results of the first in a series of experiments devoted to examining the feasibility to use tactile cues to convey detailed physiological information about more than one patient, rendered through a lower-leg tactile interface. The current experiment utilized a simulated clinical environment with 14 undergraduate students. Participants were required to interpret information delivered by the tactile interface, for two different patients, while they performed a continuous cognitively demanding task. Results indicate that under such conditions, it is possible to deliver critical information with a successful interpretation rate of approximately 85% but not without cost to the continuous demanding task. Future experiments should evaluate more tactile patterns in order to increase their interpretation success rate, and evaluate the use of these tactile cues with clinicians.

Using timbre to improve performance of larger auditory alarm sets

Identifiability and perceived urgency were compared for two sets of alarms in a healthcare inpatient setting. One contained currently used alarms where possible, with new sounds added as needed. The other was designed together, was more heterogenous, used timbre to encode intended similarities and explicitly encoded intended urgency across the set. Twenty nurses reported the identity and perceived urgency of the sounds in each set. Participants correctly identified the sound (0.89 vs. 0.77) and alarm category (0.93 vs. 0.82) more often in the new set than in the baseline set. In addition, multiple sounds in the new set were more identifiable. The new sounds also had a larger range of perceived urgency and better urgency match. The results indicate that timbre is well-suited to encode alarm groupings in larger alarm sets and that this, along with increased heterogeneity and explicit urgency mapping, improves alarm set performance. Practitioner summary: Clinical alarms are frequently misidentified. We found that making alarms more acoustically rich, using timbre to convey alarm groups, and explicitly encoding intended urgency improved identifiability and urgency match. These findings can be used to improve alarm performance across all safety-critical industries.

Using Multisensory Haptic Integration to Improve Monitoring in the Intensive Care Unit

ABSTRACT Introduction Alarm fatigue and medical alarm mismanagement reduces the quality of patient care and creates stressful work environments for clinicians. Here, the feasibility of a novel “pre-alarm” system that utilizes multisensory integration of auditory and haptic stimuli is examined as a possible solution. Methods Three vital signs (heart rate, blood pressure, and blood oxygenation) were represented by three musically distinct sounds that were combined into soundscapes and progressed through five pre-alarm zones (very low to very high). Three haptic conditions were tested with the auditory stimulus to determine the best combination of auditory and haptic stimulation. Qualitative data was collected through surveys and the NASA TLX index. Results Alterations in frequency and timbre were most effective at transmitting information regarding changing vital sign zones with comparatively higher accuracy and quicker reaction time (RT), p <.01. The addition of haptic stimuli to the auditory soundscape caused no significant decline in study participant accuracy or RT. However, two weeks after training, participants performed the tasks significantly faster (p <.001) and felt the alarm monitoring task was significantly less cognitively demanding (p <.01), compared to the unisensory condition. Participants also felt more confident in identifying changing vital signs with the addition of haptic stimuli. Discussion The current study demonstrates that multisensory signals do not diminish the perception of transmitted information and suggest efficient training benefits over unimodal signals. Multisensory training may be beneficial over time compared to unisensory training due to a stronger consolidation effect. The potential integration of haptic input with existing auditory alarm systems and training is supported.

The multisensory benefit of informative sound in visual task performance

Auditory alarms are relied upon to provide cues for industries with high-risk, multisensory performance tasks such as health care. In an anechoic chamber, anesthesiology residents (N = 25) were tested in a simulated multi-task setting, including a patient monitoring primary task with alarmed events, and a visual vigilance task. Alarm type was varied between conventional (following the International Electrotechnical Commission Standard 60601-1-8) and a novel auditory icon alarm, which provide additional information about the event causing the alarm. Novel alarm usage led to a 37% increase in vigilance accuracy and 160 ms reduction in response time, implying that the use of auditory icon alarms can provide multisensory benefits. These findings suggest that novel auditory icons help individuals by reducing the cognitive burdens of primary tasks through reducing visual search of the patient monitoring display. Therefore, auditory alarms help to reduce visual demand through offering cues to change; attention can be focused through the recognition of specifically encoded characteristics of audiovisual objects. These findings advocate for reconsideration of alarm type usage in favor of novel alarms, especially in high-stakes environments to potentially improve patient safety and outcomes.

Guidance for Custom Alarm Design: You Don’t Have to “Crank it up to 11”

Changes in alarm perception and response after prolonged daily exposure is not well studied due to the difficulties in setting up rigorous longitudinal studies in real work domains. A prime example of this is the absence of research studying how conveyed urgency and identifiability of auditory alarms change over time. We conducted a three-year study to understand how alarm performance with respect to these two measures changed over time, ostensibly due to prolonged nurse exposure. Gaining a better understanding of the relationship between these two aspects of a sound’s sensory dimension could be extremely valuable to acoustical alarm designers, as it allows them to anticipate changes in the sounds’ sensory performance over time, and not be overly sensitive to first impressions of the auditory alarm set.

Modulation of the Visual to Auditory Human Inhibitory Brain Network: An EEG Dipole Source Localization Study.

Auditory alarms are used to direct people’s attention to critical events in complicated environments. The capacity for identifying the auditory alarms in order to take the right action in our daily life is critical. In this work, we investigate how auditory alarms affect the neural networks of human inhibition. We used a famous stop-signal or go/no-go task to measure the effect of visual stimuli and auditory alarms on the human brain. In this experiment, go-trials used visual stimulation, via a square or circle symbol, and stop trials used auditory stimulation, via an auditory alarm. Electroencephalography (EEG) signals from twelve subjects were acquired and analyzed using an advanced EEG dipole source localization method via independent component analysis (ICA) and EEG-coherence analysis. Behaviorally, the visual stimulus elicited a significantly higher accuracy rate (96.35%) than the auditory stimulus (57.07%) during inhibitory control. EEG theta and beta band power increases in the right middle frontal gyrus (rMFG) were associated with human inhibitory control. In addition, delta, theta, alpha, and beta band increases in the right cingulate gyrus (rCG) and delta band increases in both right superior temporal gyrus (rSTG) and left superior temporal gyrus (lSTG) were associated with the network changes induced by auditory alarms. We further observed that theta-alpha and beta bands between lSTG-rMFG and lSTG-rSTG pathways had higher connectivity magnitudes in the brain network when performing the visual tasks changed to receiving the auditory alarms. These findings could be useful for further understanding the human brain in realistic environments.

Supporting multiple patient monitoring with head-worn displays and spearcons

In hospitals, clinicians often need to monitor several patients while performing other tasks. However, visual displays that show patients' vital signs are in fixed locations and auditory alarms intended to alert clinicians may be missed. Information such as spearcons (time-compressed speech earcons) that ‘travels’ with the clinician and is delivered by earpiece and/or head-worn displays (HWDs), might overcome these problems. In this study, non-clinicians monitored five simulated patients in three 10-min scenarios while performing a demanding tracking task. Monitoring accuracy was better for participants using spearcons and a HWD (88.7%) or a HWD alone (86.2%) than for participants using spearcons alone (74.1%). Participants using the spearcons and HWD (37.7%) performed the tracking task no differently from participants using spearcons alone (37.1%) but participants using the HWD alone performed worse overall (33.1%). The combination of both displays may be a suitable solution for monitoring multiple patients.

Inattentional deafness to auditory alarms: Inter-individual differences, electrophysiological signature and single trial classification

Inattentional deafness can have deleterious consequences in complex real-life situations (e.g. healthcare, aviation) leading to miss critical auditory signals. Such failure of auditory attention is thought to rely on top-down biasing mechanisms at the central executive level. A complementary approach to account for this phenomenon is to consider the existence of visual dominance over hearing that could be implemented via direct visual-to-auditory pathways. To investigate this phenomenon, thirteen aircraft pilots, equipped with a 32-channel EEG system, faced a low and high workload scenarii along with an auditory oddball task in a motion flight simulator. Prior to the flying task, the pilots were screened to assess their working memory span and visual dominance susceptibility. The behavioral results disclosed that the volunteers missed 57.7% of the auditory alarms in the difficult condition. Among all evaluated capabilities, only the visual dominance index was predictive of the miss rate in the difficult scenario. These findings provide behavioral evidences that other early cross-modal competitive process than top down modulation process could account for inattentional deafness. The electrophysiological analyses showed that the miss over the hit alarms led to a significant amplitude reduction of early perceptual (N100) and late attentional (P3a and P3b) event-related potentials components. Eventually, we implemented an EEG-based processing pipeline to perform single-trial classification of inattentional deafness. The results indicate that this processing chain could be used in an ecological setting as it led to 72.2% mean accuracy to discriminate missed from hit auditory alarms.

The Effects of Masking on the Detection of Alarms in Close Temporal Proximity

The Effects of Masking on the Detection of Alarms in Close Temporal Proximity

Auditory Task Irrelevance: A Basis for Inattentional Deafness.

ObjectiveThis study investigates the neural basis of inattentional deafness, which could result from task irrelevance in the auditory modality.BackgroundHumans can fail to respond to auditory alarms under high workload situations. This failure, termed inattentional deafness, is often attributed to high workload in the visual modality, which reduces one’s capacity for information processing. Besides this, our capacity for processing auditory information could also be selectively diminished if there is no obvious task relevance in the auditory channel. This could be another contributing factor given the rarity of auditory warnings.MethodForty-eight participants performed a visuomotor tracking task while auditory stimuli were presented: a frequent pure tone, an infrequent pure tone, and infrequent environmental sounds. Participants were required either to respond to the presentation of the infrequent pure tone (auditory task-relevant) or not (auditory task-irrelevant). We recorded and compared the event-related potentials (ERPs) that were generated by environmental sounds, which were always task-irrelevant for both groups. These ERPs served as an index for our participants’ awareness of the task-irrelevant auditory scene.ResultsManipulation of auditory task relevance influenced the brain’s response to task-irrelevant environmental sounds. Specifically, the late novelty-P3 to irrelevant environmental sounds, which underlies working memory updating, was found to be selectively enhanced by auditory task relevance independent of visuomotor workload.ConclusionTask irrelevance in the auditory modality selectively reduces our brain’s responses to unexpected and irrelevant sounds regardless of visuomotor workload.ApplicationPresenting relevant auditory information more often could mitigate the risk of inattentional deafness.

The Recognizability and Localizability of Auditory Alarms: Setting Global Medical Device Standards.

Objective Four sets of eight audible alarms matching the functions specified in IEC 60601-1-8 were designed using known principles from auditory cognition with the intention that they would be more recognizable and localizable than those currently specified in the standard. Background The audible alarms associated with IEC 60601-1-8, a global medical device standard, are known to be difficult to learn and retain, and there have been many calls to update them. There are known principles of design and cognition that might form the basis of more readily recognizable alarms. There is also scope for improvement in the localizability of the existing alarms. Method Four alternative sets of alarms matched to the functions specified in IEC 60601-1-8 were tested for recognizability and localizability and compared with the alarms currently specified in the standard. Results With a single exception, all prototype sets of alarms outperformed the current IEC set on both recognizability and localizability. Within the prototype sets, auditory icons were the most easily recognized, but the other sets, using word rhythms and simple acoustic metaphors, were also more easily recognized than the current alarms. With the exception of one set, all prototype sets were also easier to localize. Conclusion Known auditory cognition and perception principles were successfully applied to an existing audible alarm problem. Application This work constitutes the first (benchmarking) phase of replacing the alarms currently specified in the standard. The design principles used for each set demonstrate the relative ease with which different alarm types can be recognized and localized.

Alarm fatigue in the ward: An acoustical problem?

This article addresses the need of including acoustical perspectives in the debate on alarm fatigue within the healthcare domain. We show how conceptualisations and proposed solutions to alarm fatigue are unequally distributed across what could be called the ‘alarm chain’: a generic model of the core structural elements and dynamic relations that constitute any alarm scenario. A focal point in the alarm chain – the ‘alarm mediation cleft’ – seems to divide the alarm fatigue literature from the segment of the alarm literature that deals with auditory alarm design. The current healthcare discourse on alarm fatigue is centred around the ‘premediated alarm phase’, which has the consequence of an unfortunate dichotomous approach to the functionality of sound. We address some shortcomings of this approach and outline some methodological implications and potentials of searching for signs of alarm fatigue in the ‘post-mediated alarm phase’.

Composing alarms: considering the musical aspects of auditory alarm design

ABSTRACTShort melodies are commonly linked to referents in jingles, ringtones, movie themes, and even auditory displays (i.e., sounds used in human–computer interactions). While melody associations can be quite effective, auditory alarms in medical devices are generally poorly learned and highly confused. Here, we draw on approaches and stimuli from both music cognition (melody recognition) and human factors (alarm design) to analyze the patterns of confusions in a paired-associate alarm-learning task involving both a standardized melodic alarm set (Experiment 1) and a set of novel melodies (Experiment 2). Although contour played a role in confusions (consistent with previous research), we observed several cases where melodies with similar contours were rarely confused – melodies holding musically distinctive features. This exploratory work suggests that salient features formed by an alarm’s melodic structure (such as repeated notes, distinct contours, and easily recognizable intervals) can increase the likelihood of correct alarm identification. We conclude that the use of musical principles and features may help future efforts to improve the design of auditory alarms.

Do Learned Alarm Sounds Interfere With Working Memory?

To assess whether identifying (or ignoring) learned alarm sounds interferes with performance on a task involving working memory. A number of researchers have suggested that auditory alarms could interfere with working memory in complex task environments, and this could serve as a caution against their use. Changing auditory information has been shown to interfere with serial recall, even when the auditory information is to be ignored. However, previous researchers have not examined well-learned patterns, such as familiar alarms. One group of participants learned a set of alarms (either a melody, a rhythmic pulse, or a spoken nonword phrase) and subsequently undertook a digits-forward task in three conditions (no alarms, identify the alarm, or ignore the alarm). A comparison group undertook the baseline and ignore conditions but had no prior exposure to the alarms. All alarms interfered with serial recall when participants were asked to identify them; however, only the nonword phrase interfered with recall when ignored. Moreover, there was no difference between trained and untrained participants in terms of recall performance when ignoring the alarms, suggesting that previous training does not make alarms less ignorable. Identifying any alarm sound may interfere with immediate working memory; however, spoken alarms may interfere even when ignored. It is worth considering the importance of alarms in environments requiring high working memory performance and in particular avoiding spoken alarms in such environments.

Driver Performance in a Cooperative Adaptive Cruise Control String

Cooperative Adaptive Cruise Control (CACC) has been proposed as a method to increase highway capacity and possibly enhance safety. Two experiments were conducted in a driving simulator to verify that drivers with CACC would effectively monitor the system’s longitudinal control and override the system in the event that greater braking authority was needed than the system was designed to provide. In the first experiment, the emergency response of drivers with the CACC was compared with that of drivers who manually controlled following distance within a string of vehicles. The CACC group experienced markedly fewer crashes and had longer mean time-to-collision. The second experiment examined whether the CACC safety benefit was the result of the CACC system’s limited automatic braking authority, an auditory alarm, or both. The results suggest that both auto-braking and an auditory alarm are necessary to achieve a crash reduction benefit, although the alarm alone may promote less severe collisions.

Pip and Pop

Dynamic and complex command and control situations often require the timely recognition of changes in the environment in order to detect potentially malicious actions. Change detection can be challenging within a continually evolving scene, and particularly under multitasking conditions whereby attention is necessarily divided between several subtasks. On-screen tools can assist with detection (e.g., providing a visual record of changes, ensuring that none are overlooked), however, in a high workload environment, this may result in information overload to the detriment of the primary task. One alternative is to exploit the auditory modality as a means to support visual change detection. In the current study, we use a naval air-warfare simulation, and introduce an auditory alarm to coincide with critical visual changes (in aircraft speed/direction) on the radar. We found that participants detected a greater percentage of visual changes and were significantly quicker to detect these changes when they were accompanied by an auditory alarm than when they were not. Furthermore, participants reported that mental demand was lower in the auditory alarm condition, and this was reflected in reduced classification omissions on the primary task. Results are discussed in relation to Wickens’ multiple resource theory of attention and indicate the potential for using the auditory modality to facilitate visual change detection.

Overview of the 2016 US Food and Drug Administration Circulatory System Devices Panel Meeting on the AngelMed Guardian System.

On March 16, 2016, the US Food and Drug Administration (FDA) convened a meeting of the Circulatory System Devices Panel to consider a premarket approval application for the AngelMed Guardian System based on the results of the pivotal ALERTS trial (AngelMed for Early Recognition and Treatment of STEMI) (URL: http://www.clinicaltrials.gov. Unique identifier: NCT00781118). The system comprises an implantable device similar to a single-chamber pacemaker, an external device that the patient carries, and a physician console. The device analyzes ST-segment shift through a single active-fixation lead in the right ventricular apex. If ST shift is identified, then the implantable device vibrates and the external device flashes and sounds an auditory alarm. More than 1 in 3 acute myocardial infarctions occur without chest pain, most commonly in women, diabetic patients, and the elderly. ST shift occurs rapidly in humans following coronary balloon occlusion.1 The AngelMed Guardian aims to reduce time to presentation by alerting the patient to ST shift even in the absence of symptoms. The ALERTS trial tested the safety and effectiveness of the Guardian System. A Bayesian adaptive design was used to adjust sample size based on interim treatment effect. The trial enrolled high-risk patients with a history of coronary artery disease (97% had previous revascularization). The trial was stopped early because of concerns that the predictive model did not accurately account for new Q waves. Nine hundred ten patients had the Guardian implanted (451 in the treatment arm versus 456 in the control arm with the device deactivated). Study …

Human error and response to alarms in process safety

&lt;p&gt;Operadores humanos responden a alarmas en condiciones normales y también en situaciones inesperadas y anormales en tiempo real. El objetivo de este estudio consiste en aumentar el conocimiento de las reacciones humanas a alarmas en el ámbito laboral. Describe como los humanos pueden contribuir a accidentes y presta atención a la seguridad del proceso que se efectúa en el tiempo de reacción a las alarmas de sistema. Este experimento fue ejecutado para investigar si hay diferencias en respuestas diferenciales a alarmas visuales comparándolas a alarmas auditivas. Los resultados indican que las alarmas visuales son percibidas de manera más eficiente que las alarmas auditivas. Incluso, se pudo ver una correlación negativa entre la cantidad de errores y el tiempo de reacción, lo que indica una diferencia individual en su disposición a errores cuando reaccionan a alarmas visuales en operaciones de supervisión.&lt;/p&gt;

Auditory Alarms: A Message from Titanic

Tragedy involves emotional learning as it captures accounts in different ways and happens as a remarkable scene to characterize the so-called auditory alarms. Drawing on historiography study, this paper explores the RMS Titanic with a view from Three-Alarms Theory (TAT). It discusses True Alarm, False Alarm and Learned Alarm, and concludes with the high incidence of false alarms and its impact on different classes of sound as alarms in creative accounting treatise for future theory and research.

High Rate of Inattentional Deafness in Simulated Air Traffic Control Tasks

The Air Traffic Control (ATC) environment is complex and safety-critical; operators work in dynamic situations and must make high-risk decisions under stress and temporal pressure. The high perceptual load involved in ATC means that controllers’ attention must be shared between several subtasks, with few or no remaining attentional capacity for processing information that is not related directly to the focal task. In this kind of situation, the likelihood of a controller failing to become aware of an auditory alarm, i.e. inattentional deafness, is high. We designed an ecological ATC thanks to the simulation environment called the “LABY” microworld. Twenty participants were required to guide one (low cognitive load) or two planes (high cognitive load) around a given route, while dealing with visual notifications relating to peripheral aircrafts. During the task, participants were played either standard tones which they were told to ignore, or deviant tones (“the alarm”, probability = 0.20) which they were told to report (20 alarms per scenario). We hypothesized that the detection rate of auditory alarms will decrease with cognitive workload. In order to explore this possibility, Behavioral results showed that 28.8% of alarms were not reported when guiding one plane, and up to 46.2% when guiding two planes (high load). The cognitive load increase led to a reduced visual notification detection rate, but the performance to guiding the central aircrafts was maintained, as well as the reaction times to report auditory alarms when perceived. This high rate of inattentional deafness is essential to further physiological studies on alarm omission in aeronautics, such as ERP or eye movement analysis. Potential applications are related to the integrative online detection and prevention of alarm omission, and the online measurement of workload in ecological situation.