About the importance of auditory alarms during the operation of a plant simulator

An experiment was carried out to estimate the effect of auditory alarms on the work of a plant operator in the context of a computer simulation. The process simulator was implemented so that each of eight machines (computer numeric controlled [CNC] robots) produced sounds to indicate its status over time. Each sound was designed to reflect the ‘real-world' semantic of the actual breakdown event. As many as 32 different auditory alarms plus six normal machine sounds could be played at once. We attempted to design the auditory alarms so that none would be masked (rendered inaudible) by other auditory alarms. Eight students of computer science operated our process simulation program of an assembly line with the eight CNC robots. Relevant information of disturbances and machine breakdowns was given in a visual (test condition 1), and in visual and auditory form (test condition 2). The results indicate that the additional feedback of auditory alarms significantly improves operator performance and increases some mood aspects positivel

Human-centred design of clinical auditory alarms

Auditory alarms are commonly badly designed, providing little to no information or guidance. In the healthcare context, the poor acoustics of alarms is one contributor for the noise problem. The goal of this thesis is to propose a human-centred methodology for the design of clinical auditory alarms, by making them less disruptive and more informative, thus improving the healthcare soundscape. It implements this methodology from concept to evaluation and validation, combining psychoacoustics with usability and user experience methods. Another aim of this research consisted in understanding the limitations and possibilities offered by online tools for scientific studies. Thus, different processes and methodologies were implemented, and corresponding results were discussed. To understand the acoustic healthcare environment, field visits, interviews, and surveys were performed with healthcare professionals. Additionally, sound pressure levels and frequency analysis of several surgeries in different hospitals provided specific sound design requirements, which were added to an existent body of knowledge on clinical alarm design. A second stage consisted in prototyping very simple sounds to comprehend which temporal and spectral parameters of sound could be manipulated to communicate clinical information. Parameters such as frequency, speed, onset, and rhythm were studied, and relations between subjective perception and physical parameters were established. In parallel, and heavily influenced by the new IEC 60601-1-8 - General requirements, tests and guidance for alarm systems in medical electrical equipment and medical electrical systems, a design strategy with auditory icons was created. This strategy intended to provide as much information as possible in an auditory alarm. To do so, it involved two main components: a priority pointer indicating the priority of the alarm; an auditory icon indicating the cause of the alarm. A third component indicating increasing or decreasing tendency of the vital sign was designed, but not validated with users. After online validation of the priority pointer and auditory icon for eight categories (cardiac, drug administration, ventilation, blood pressure, perfusion, oxygen, temperature, and power down), a new library of clinical auditory alarms is proposed.Os alarmes auditivos são habitualmente mal concebidos, dando poucas informações ou orientações perante a situação que despoletou o aviso. No contexto da saúde, a má acústica dos alarmes é um dos contribuidores para o problema do ruído. O objetivo desta tese é o de melhorar a paisagem sonora em ambientes clínicos, propondo uma metodologia centrada no Humano para o design de alarmes auditivos clínicos, tornando-os menos disruptivos e mais informativos. Essa metodologia é implementada desde o conceito até a avaliação e validação, combinando métodos da psicoacústica com métodos de usabilidade e experiência do utilizador. Outro objetivo desta investigação é o de compreender as limitações e possibilidades oferecidas pelas ferramentas online para estudos científicos. Assim, diversos processos e metodologias foram implementados, e os respetivos resultados são discutidos. Para compreender o ambiente acústico clínico, foram realizadas visitas de campo, entrevistas e inquéritos com profissionais de saúde. Além disso, avaliou-se o nível de pressão sonora e frequências de várias cirurgias em diferentes hospitais. Esta atividade forneceu requisitos específicos de design de som que foram adicionados a um corpo existente de conhecimento sobre design de alarmes clínicos. Uma segunda etapa consistiu na prototipagem de sons simples para compreender que parâmetros temporais e espectrais do som poderiam ser manipulados para comunicar informações clínicas. Parâmetros como frequência, velocidade, envelope e ritmo foram estudados, e as relações entre a perceção subjetiva e os parâmetros físicos foram estabelecidas. Paralelamente, e fortemente influenciado pela nova norma IEC 60601-1-8 - Requisitos gerais, testes e orientações para sistemas de alarme em equipamentos médicos elétricos e sistemas médicos elétricos, foi criada uma estratégia de design com ícones auditivos. Essa estratégia pretendia incorporar o máximo de informações num alarme auditivo. Para isso, envolveu dois componentes principais: um ponteiro de prioridade que indica a prioridade do alarme; e um ícone auditivo que indica a causa do alarme. Um terceiro componente de tendência (aumento ou diminuição do valor do sinal vital) foi criado, mas não validado com utilizadores. Após a validação do ponteiro de prioridade e ícone auditivo para oito categorias (cardíaco, administração de medicamentos, ventilação, pressão arterial, perfusão, oxigénio, temperatura e falha de equipamento), propõe-se uma nova biblioteca de alarmes auditivos clínicos

EEG-engagement index and auditory alarm misperception: an inattentional deafness study in actual flight condition

The inability to detect auditory alarms is a critical issue in many do- mains such as aviation. An interesting prospect for flight safety is to understand the neural mechanisms underpinning auditory alarm misperception under actual flight condition. We conducted an experiment in which four pilots were to re- spond by button press when they heard an auditory alarm. The 64 channel Cognionics dry-wireless EEG system was used to measure brain activity in a 4 seat light aircraft. An instructor was present on all flights and in charge of initi- ating the various scenarios to induce two levels of task engagement (simple navigation task vs. complex maneuvering task). Our experiment revealed that inattentional deafness to single auditory alarms could take place as the pilots missed a mean number of 12.5 alarms occurring mostly during the complex maneuvering condition, when the EEG engagement index was high

Comparing verbal media for alarm handling: Speech versus textual displays

The rise of computers in command and control domains has meant that control operations can be performed via desk-based visual display terminals. This trend has also produced the potential to display information to operators in a variety of formats. Of particular interest has been the use of text-based displays for alarm presentation. There are possible limitations to the use of text for alarm presentation, not least of which is the need for a dedicated alarms display screen (or, at least, a display page). Given the capability of computers to synthesize speech, it is possible that speech-based alarms could generate the same information as text-based displays without the need for dedicated screen space. In this paper an experimental comparison of speech-based and text-based displays for presentation of alarms is reported. The findings show that speech leads to longer response times than text displays, but that it has minimal effect on the efficacy of fault handling. The results are discussed within the alarm initiated activities framework and implications for alarm system design are outlined

Pip and Pop: When auditory alarms facilitate visual change detection in dynamic settings

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

Effects of Visibility and Alarm Modality on Workload, Trust in Automation, Situation Awareness, and Driver Performance

Driving demands sustained driver attention. This attentional demand increases with decreasing field visibility. In the past researchers have explored and investigated how collision avoidance warning systems (CAWS) help improve driving performance. The goal of the present study is to determine whether auditory or tactile CAWS have a greater effect on driver performance, perceived workload, system trust, and situation awareness (SA). Sixty-three undergraduate students from Old Dominion University participated in this study. Participants were asked to complete two simulated driving sessions along with Motion Sickness Susceptibility Questionnaire, Background Information Questionnaire, Trust Questionnaire, NASA Task Load Index Questionnaire, Situation Awareness Rating Technique Questionnaire, and Simulator Sickness Questionnaire. Analyses indicated that drivers in the tactile modality condition had low perceived workload. Drivers in the heavy fog visibility condition had the highest number of collisions and red-light tickets. Drivers in the heavy fog condition also reported having the highest overall situation awareness. Drivers in the clear visibility condition trusted tactile alarms more than the auditory alarms, whereas drivers in the heavy fog condition trusted auditory alarms more than tactile alarms. The findings of this investigation could be applied to improve the design of CAWS that would help improve driver performance and increase safety on the roadways

Evaluating Dynamic ‘Landing Gear Unsafe’ Auditory Alerts as a Defense Against Habituation

Auditory alerts are widely used in today\u27s daily routine. Unlike their visual counterparts, auditory alerts can be used to capture someone\u27s attention, even though the user is not within visual range. As beneficial as auditory alerts can be, it is possible to become habituated to alerts. Habituation is the elimination of a response as a result of continuous exposure to a stimulus. In this small-scale study, methods to reduce pilot habituation to the \u27landing gear unsafe\u27 auditory alert were investigated. Ten subjects executed eight non-precision instrument approaches that exposed the subjects to the \u27landing gear unsafe\u27 auditory alert for a prolonged period of time. Subjects were exposed to four different landing gear auditory alerts: (a) a constant alert over time (control), (b) an alert that changed in pitch over time, (c), an alert that changed in loudness over time, and (d) an alert that changed in duration over time. During the study, the researcher tracked whether the subjects complied with all required procedures; afterwards, subjects completed a questionnaire about their perceptions of the alerts. The results showed the alert that changed in pitch over time yielded the most accurate procedures. The questionnaire data also favored the alert that changed in pitch over time

AUDITORY ALARMS IN THE INTENSIVE CARE UNIT: EXPERIMENTAL AND OBSERVATIONAL STUDIES

There are many problems associated with the number of auditory warnings in hospital environments such as the Intensive Care Unit. As the amount of medical technology used to monitor a patient's condition increases, there is a concomitant increase in the number of auditory warnings. Each piece of equipment has its own alarm and often the sounds used are inappropriate. For example, the sounds are often too loud, too insistent and are irritating to staff, distracting them from other tasks. A further feature of sounds used for auditory alarms is that there is, at present, no agreement between manufacturers on the types of sounds used. This means that the same item of equipment can have different alarms if produced by different manufacturers. Subsequently there is the potential for confusion between alarms to occur if sounds are similar. The research presented in this thesis aims to investigate the psychological dimension of confusion between alarm sounds and the correct identification of a set of twelve auditory warnings currently in use in the I.C.U. Derriford Hospital, Plymouth. Hence, the first set of experiments examines the learning and retention of the set of auditory warnings in a laboratory setting. However, the many problems regarding auditory warnings should not be considered in isolation and in order to determine the types of activities undertaken by staff in the I.C.U. environment when alarms are activated, two observational studies were undertaken. The first study used a video camera and the second study involved direct observation using two observers. A series of tasks were developed that used the multiple resources literature as a framework and also represented tasks undertaken in the environment of the I.C.U. In the second experiment, participants were again required to learn and retain the set of auditory warnings. The tasks were introduced during the return stage of the experiment in order to examine first, whether there was an effect on the primary task of correctly identifying the sounds and whether the confusions between sounds increased or changed, and second to examine performance on the secondary tasks. The results showed that for all experiments in general participants required few trials to learn the sounds and the information was retained for a period of over one week. The results also showed that features of some sounds were easier to learn than other sounds and that certain sounds were consistently confused during each experiment. When the tasks were introduced performance on the primary task remained fairly constant, with no overall change or increase in the number of confusions between sounds. However, there was a decrement in the performance of the secondary tasks, as predicted by the dual-task literature. In conclusion, the results suggest that identification of sounds may depend on a global, overall label for a sound, such as a 'melodic' sound or a 'continuous' sound, with the more intricate details undetected by participants. The results also suggest that participants in the laboratory may alter their strategies to maintain performance on the primary task, by either responding more rapidly to task demands or by consciously deciding not to respond to one of the secondary tasks.Royal Aircraft Establishment, Farnboroug

Too Loud: A Project for sound reduction in the Neonatal Intensive Care Unit

Sound levels in any intensive care unit environment are significantly higher than the recommended volume. The neonatal intensive care unit (NICU) is included in this aggregate that frequently exceeds advised levels. There are consequences associated with increased sound, such as slower language development and behavior issues. Not only are babies subjected to physiological effects, but there is potential for psychological detriment as well, such as behavioral issues (Bremmer, 2003). Many solutions for this issue have been proposed, including lowering phone volumes, putting rubber shoes on furniture and switching audio alarms to visual alarms. One specific intervention that may reduce the level of noise in the NICU setting is a digital interface system (“SoundEar II Sign,” n.d.). This effort and others will reduce the noise volume and allow for better baby development, both physiologically and psychologically. This process was presented to the nursing staff at the Baptist Health Paducah NICU. Proposed interventions included the visual alarm system and low cost guidelines for the nurses to begin to implement

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