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Abstract

The pulse oximeter is a critical monitor in anesthesia practice designed to improve patient safety. Here, we present an approach to improve the ability of anesthesiologists to monitor arterial oxygen saturation via pulse oximetry through an audiovisual training process. Fifteen residents' abilities to detect auditory changes in pulse oximetry were measured before and after perceptual training. Training resulted in a 9% (95% confidence interval, 4%-14%, P = 0.0004, t166 = 3.60) increase in detection accuracy, and a 72-millisecond (95% confidence interval, 40-103 milliseconds, P < 0.0001, t166 = -4.52) speeding of response times in attentionally demanding and noisy conditions that were designed to simulate an operating room. This study illustrates the benefits of multisensory training and sets the stage for further work to better define the role of perceptual training in clinical anesthesiology.

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... Increased task demands have been shown to degrade performance to detecting pitch differences of the pulse oximeter. 1,2 Although control of the acoustic environment in our workplace is increasingly out of our control, 3 it is exceedingly important to invoke concepts from the fields of music perception and cognition into standardization and refinement of the pulse oximeter. ...
... 15 The just-noticeable difference of pitch discrimination (in a quiet environment) is 1/12th of a semitone, 16 but pitch perception performance is hampered by increased attentional demands. 1,2 Therefore, it is imperative to ensure that the pitch scale used by pulse oximeters increases the chance of the anesthesiologist to recognize and anticipate the clinical trend of his or her patients in the operating room and intensive care unit. Comparing linear and logarithmic scales, anesthesiologists could produce significantly more accurate judgments of both absolute oxygenation values and size of oxygenation level difference when a logarithmic, rather than a linear, scale was used. ...
... In concept, this is in line with participants detecting subtle pitch differences without other cognitive demands. 1,2 Most anesthesiologists likely fall in the group of individuals between amusia and AP. Pitch perception and relative pitch for ecological and nonecological stimuli are typically better than one imagines. ...
... Contrary to this, the pairing of weaker stimuli may be as effective in driving behavior, and most importantly could dramatically reduce many of the negative attributes (e.g., fatigue, stress) associated with very loud or bright stimuli [3,34,58]. Based on such examples, we advocate that knowledge and application of findings from multisensory research have the potential to greatly aid in the design and implementation of safer and more comfortable clinician workplaces [4,14]. ...
... The addition of background auditory noise further degraded their performance. However, clinical accuracy and speed of response were improved by just two hours of multisensory perceptual training over a two-day period [4,14]. This is a clear demonstration that a brief period of multisensory perceptual training can enhance clinicians' response to clinically meaningful signals in a high attentional and sensory demand environment similar to the ICU or operating room (OR). ...
... The utility of applying the concepts of multisensory integration to the clinical environment may ultimately lie in the increased ability to process complex information within an attentionally demanding setting, and in the decreased need for high intensity stimuli as primary alarm delimiters. There has been significant work showing the problems with alarm fatigue and a subsequent call-to-action to improve patient monitoring [4,9,12,14,17]. We believe that the neuroscience concepts articulated in this manuscript provide a powerful set of tools to design better alarms and patient monitoring environments for the clinician and patient. Clinicians are already required to integrate information across modalities; now is the time for alarms and patient monitors to adopt these neuroscience principles in an efficient, effective, and safe manner. ...
Article
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The intensive care unit (ICU) of a hospital is an environment subjected to ceaseless noise. Patient alarms contribute to the saturated auditory environment and often overwhelm healthcare providers with constant and false alarms. This may lead to alarm fatigue and prevent optimum patient care. In response, a multisensory alarm system developed with consideration for human neuroscience and basic music theory is proposed as a potential solution. The integration of auditory, visual, and other sensory output within an alarm system can be used to convey more meaningful clinical information about patient vital signs in the ICU and operating room to ultimately improve patient outcomes.
... The issue is not so much the ability to discriminate the pitch, as practitioners are typically able to detect subtle pitch differences without distraction, as we have demonstrated here. The problem is pitch discrimination with high attentional load conditions, the conditions that practitioners are subjected to in the healthcare environment (Schlesinger et al., 2014;Seagull and Sanderson, 2001). One of the overlooked facets is the ability of the practitioner to parse out multisensory information into relevant and irrelevant. ...
... One of the overlooked facets is the ability of the practitioner to parse out multisensory information into relevant and irrelevant. Schlesinger et al. (2014) found that through multisensory training (NOT aural training), practitioners had improved attentional and cognitive demand processing and improved performance with subtle pitch discrimination in high attentional load (distracting) environments. The studies presented here provide a baseline comparison of the two scales, and as a next step it would be very interesting to compare the two scales used here in Schlesinger's paradigm, thus moving us closer to the conditions under which anaesthetists work in the clinical environment. ...
... Our experiments were conducted in quiet laboratory conditions and participants were not required to carry out any secondary tasks. Our next steps would be to conduct a similar study using an alreadytested laboratory simulation paradigm (such as that by Schlesinger et al., 2014), testing other potential scales, and developing tests that can be carried out in situ. ...
Article
This study compared the ability of forty anaesthetists to judge absolute levels of oxygen saturation, direction of change, and size of change in saturation using auditory pitch and pitch difference in two laboratory-based studies that compared a linear pitch scale with a logarithmic scale. In the former the differences in saturation become perceptually closer as the oxygenation level becomes higher whereas in the latter the pitch differences are perceptually equivalent across the whole range of values. The results show that anaesthetist participants produce significantly more accurate judgements of both absolute oxygenation values and size of oxygenation level difference when a logarithmic, rather than a linear, scale is used. The line of best fit for the logarithmic function was also closer to x = y than for the linear function. The results of these studies can inform the development and standardisation of pulse oximetry tones in order to improve patient safety. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
... Perceptual training with feedback has been shown to successfully narrow the width of TBW (Powers et al., 2009(Powers et al., , 2016Schlesinger et al., 2014;Stevenson et al., 2013), accompanied by increased neural network plasticity centred on the posterior superior temporal sulcus (Powers et al., 2012). Moreover, individuals who seem to benefit most are those whose TBWs are the largest before training (Powers et al., 2009;Stevenson et al., 2013). ...
... Moreover, individuals who seem to benefit most are those whose TBWs are the largest before training (Powers et al., 2009;Stevenson et al., 2013). Apart from evidence from university students and young adults (Powers et al., 2009(Powers et al., , 2012(Powers et al., , 2016Schlesinger et al., 2014;Stevenson et al., 2013), such reduction in the width of the TBW has also been observed in older adults after temporal discrimination training (Setti et al., 2014). More evidence supporting the experience-dependent plasticity of multisensory temporal integration comes from musically trained individuals whose audiovisual TBW is much shorter than non-musicians (Bidelman, 2016). ...
... A recent study conducted with university students found that the effect of audiovisual simultaneity judgement training could not be generalized to other multisensory tasks, but could result in improvements in unisensory (visual) temporal acuity (Powers et al., 2016). Another interesting study demonstrated that a shortened TBW after perceptual training was accompanied by improved ability to detect auditory changes in pulse oximetry in a group of resident anaesthesiologists (Schlesinger et al., 2014). Given the inconsistent findings and limited number of available studies, future research is needed to further examine the generalization effect of multisensory temporal training. ...
Article
Multisensory temporal integration could be compromised in both autism spectrum disorders (ASD) and schizophrenia spectrum disorders (SSD) and may play an important role in perceptual and cognitive impairment in these two disorders. This review aimed to quantitatively compare the sensory temporal acuity between healthy controls and the two clinical groups (ASD and SSD). Impairment of sensory temporal integration was robust and comparable in both patients with SSD (Hedges' g=0.91, 95%CI[0.62-1.19]; Z=6.21, p<.001) and ASD (Hedges' g=0.85, (95%CI[0.54-1.15]; Z=5.39, p<.001). By further separating studies into unisensory and multisensory (bimodal: audiovisual) ones, subgroup analysis indicated heterogeneous and unstable effects for unisensory temporal binding in the ASD group, but a more consistent and severe impairment in multisensory temporal integration represented by an enlarged temporal binding window in both clinical groups. Such multisensory dysfunction is associated with symptoms like hallucinations and impaired social communications. Future studies focusing on improving multisensory temporal functions may have important implications for the amelioration of schizophrenia and autistic symptoms.
... In addition, these studies and others have revealed a number of other salient characteristics concerning multisensory temporal acuity. These include that it: 1) has a great deal of individual variability van Eijk et al., 2008), 2) differs depending upon stimulus type and task (Kasper et al., 2014;Megevand et al., 2013;Stevenson and Wallace, 2013;van Eijk et al., 2008van Eijk et al., , 2010Vroomen and Stekelenburg, 2011), and 3) is malleable in response to perceptual training (Keetels and Vroomen, 2008;Powers et al., 2012Powers et al., , 2009Schlesinger et al., 2014;Stevenson et al., 2012cStevenson et al., , 2013aStevenson et al., , 2013b and across development (Hillock et al., 2011;Hillock-Dunn and Wallace, 2012;Joanne Jao et al., 2014;Johannsen and Roder, 2014;Lewkowicz, 2012;Polley et al., 2008;Shi and Muller, 2013) and aging (Bates and Wolbers, 2014;DeLoss et al., 2013;Diaconescu et al., 2013;Freiherr et al., 2013;Hugenschmidt et al., 2009;Mahoney et al., 2012Mahoney et al., , 2014Mozolic et al., 2012;Stevenson et al., 2015). ...
... Furthermore, multisensory systems are characterized by a great deal of plastic capacity, a feature that has been explored extensively in the temporal realm. Thus, through recalibration (Fujisaki et al., 2004; and perceptual learning (Powers et al., , 2009Schlesinger et al., 2014;Stevenson et al., 2013b), it has been demonstrated that an individual's perception of synchrony and the window of time within which that individual will perceptually bind paired stimuli can be modified. Given the malleability of multisensory processing, it seems plausible then that these processes may become more liberal in the window of time with which they perceptually bind incoming sensory information based upon its reliability or intensity. ...
... Since having an appropriately sized temporal binding window ensures proper multisensory integration, one avenue of future research should investigate whether or not clinical populations with enlarged temporal windows will show a corresponding widening of these windows with changing stimulus properties (i.e., stimulus intensities as described in the current study) or with increasing levels of stimulus complexity Vroomen and Stekelenburg, 2011). Furthermore, given previous demonstrations of how one can improve multisensory temporal precision through perceptual learning (Powers et al., , 2009Schlesinger et al., 2014;Stevenson et al., 2013b), future studies applying such training to clinical populations as possible therapeutic tool may prove fruitful. Emerging evidence suggests enormous developmental plasticity in multisensory temporal function (Hillock et al., 2011;Hillock-Dunn and Wallace, 2012;Stevenson et al., 2013b). ...
... Haptic feedback also allows quicker target localization and texture discrimination (Akamatsu, Sato, & MacKenzie, 1994), requires few mental resources (MacLean, 2009), and does not require additional visual attention (Alirezaee, Girgis, Kim, Schlesinger, & Cooperstock, 2017;Kolodzey, Grantcharov, Rivas, Schijven, & Grantcharov, 2017;Patterson, Winterbottom, & Pierce, 2006). Therefore, haptic stimulation may minimize sensory and information overload (Jones, 2011) and is expected to aid in overcoming the current issues in alarm perception (Schlesinger, Stevenson, Shotwell, & Wallace, 2014). ...
... Finally, training with a multisensory alarm system benefits performance. Unisensory training is effective for medical professionals in improving frequency perception and, thus, alarm response (Schlesinger et al., 2014) but multisensory training, such as musical training, has a number of additional benefits in as little as two weeks (Luo et al., 2012;Pantev, Lappe, Herholz, & Trainor, 2009). Thus, it can be expected that robust training and experiential learning can result in more accurate use of a multisensory system via enhanced connections between sensory and motor cortices. ...
Article
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.
... D. Perceptual learning paradigms have been shown to reliably increase individual's multisensory temporal acuity, as indexed by a narrowing of the TBW. Adapted from Schlesinger et al. (2014). be at 0. However, the PSS in most individuals is typically observed when the auditory component of a stimulus pair slightly lags the visual stimulus component [for review, see van Eijk et al. (2008)]. ...
... Third, the TBW continues to mature late into development, with it being broader than for adults well into adolescence (Hillock et al., 2011;Hillock-Dunn & Wallace, 2012a). Finally, the TBW has been shown to be malleable in multiple ways, both adjusting to the temporal statistics of the environment (recalibration (Fujisaki et al., 2004;, 2008bNavarra et al., 2005;Stetson et al., 2006;Vroomen et al., 2004)), and in perceptual plasticity studies showing that it can be substantially narrowed with feedback training (Powers et al., 2009(Powers et al., , 2012Stevenson et al., 2013;Schlesinger et al., 2014). ...
... Other studies currently being carried out as part of the formative (and, more recently, summative) testing include the audibility of the alarm signals in realistic listening conditions. Findings thus far indicate that the sounds work well in relatively low signal-to-noise ratios (a finding being demonstrated for alarm signals more generally in other studies; Schlesinger et al., 2018;Schlesinger, Stevenson, Shotwell, & Wallace, 2014;Stevenson, Schlesinger, & Wallace, 2013) and that the presence of the pointer enhances audibility. The pointer in particular was found to be audible in noise that was four times louder. ...
... Our summative testing follows the broad protocols of the formative testing, with additional researchers testing the sounds in a range of clinical environments using protocols yet to be developed as well as using accepted and published protocols (Schlesinger et al., 2014;Stevenson et al., 2013). There is also other, related work being conducted. ...
Article
The reserved set of audible alarm signals embodied within the global medical device safety standard, IEC 60601-1-8, is known to be problematic and in need of updating. The current alarm signals are not only suboptimal, but there is also little evidence beyond learnability (which is known to be poor) that demonstrates their performance in realistic and representative clinical environments. In this article, we describe the process of first designing and then testing potential replacement audible alarm signals for IEC 60601-1-8, starting with the design of several sets of candidate sounds and initial tests on learnability and localizability, followed by testing in simulated clinical environments. We demonstrate that in all tests, the alarm signals selected for further development significantly outperform the current alarm signals. We describe the process of collecting considerably more data on the performance of the new sounds than exists for the current sounds, which ultimately will be of use to end users. We also reflect on the process and practice of working with the relevant committees and other practical issues beyond the science, which also need constant attention if the alarms we have developed are to be included successfully in an updated version of the standard.
... In concert with the adaptive value ascribed to possessing extended windows of time over which sensory information is bound, findings suggest that the TBW is highly plastic (Powers et al., 2009;Stevenson et al., 2013Stevenson et al., , 2017aSchlesinger et al., 2014;De Niear et al., 2017), dependent upon stimulus structure and complexity , and perhaps most importantly, TBWs are anomalous in psychopathology. Indeed, while the general characterization of multisensory processes-and their temporal profile-in psychopathological conditions such as ASD and SZ populations has yield conflicting results, in the case of SZ for instance, stronger , similar (Wynn et al., 2014;Zvyagintsev et al., 2017), and weaker (Williams et al., 2010) multisensory facilitation vs. controls has been reported, the reports regarding multisensory TBWs in psychopathology are largely congruent-inclusively across the distinct pathologies (see Zhou et al., 2018; for a recent review and meta-analysis of multisensory temporal function in ASD and SZ). ...
... An interesting area of investigation the current results apply to is that of perceptual learning within psychopathology and the potential clinical utility of perceptual learning as a tool in remediation. In fact, multisensory temporal function has been shown to be highly plastic and work has shown that multisensory temporal acuity can be improved via perceptual training (Powers et al., 2009(Powers et al., , 2012Stevenson et al., 2013Stevenson et al., , 2017aSchlesinger et al., 2014;De Niear et al., 2017). Clinically, this approach may hold promise in strengthening sensory and perceptual representations, which may cascade into higher-order benefits, such as enhanced speech comprehension. ...
... Current pulse oximetry sonification relies on the clinician's ability to discern relative and absolute pitch (Brown et al., 2015). Multisensory training has been suggested as a way to improve clinicians' perception of the pitch of pulse oximetry tones (Schlesinger et al., 2014). However, this approach is unlikely to work across different pulse oximeter models, which use different mappings of tones to SpO 2 Santamore and Cleaver, 2004). ...
... Therefore implementing a Tremolo sonification display in a clinical setting might not require extensive training time and costs. The time and expense of multisensory training to improve pitch perception on existing pulse oximeters in an effort to improve patient monitoring (Schlesinger et al., 2014) may be unnecessary if a sonification design can provide even better improvements that work well in the clinical environment. ...
Article
Recent guidelines recommend oxygen saturation (SpO2) levels of 90%-95% for preterm neonates on supplemental oxygen but it is difficult to discern such levels with current pulse oximetry sonifications. We tested (1) whether adding levels of tremolo to a conventional log-linear pulse oximetry sonification would improve identification of SpO2 ranges, and (2) whether adding a beacon reference tone to conventional pulse oximetry confuses listeners about the direction of change. Participants using the Tremolo (94%) or Beacon (81%) sonifications identified SpO2 range significantly more accurately than participants using the LogLinear sonification (52%). The Beacon sonification did not confuse participants about direction of change. The Tremolo sonification may have advantages over the Beacon sonification for monitoring SpO2 of preterm neonates, but both must be further tested with clinicians in clinically representative scenarios, and with different levels of ambient noise and distractions.
... Multisensory temporal processing is not an immutable characteristic of an individual, but is in fact quite dynamic. Highlighting this dynamism, multisensory temporal perception has been shown to be malleable via two forms of perceptual learning (Fig. 4B), bottom-up recalibration through exposure [Fujisaki, Shimojo, Kashino, & Nishida, 2004;Harrar & Harris, 2008;Keetels & Vroomen, 2008;Miyazaki, Yamamoto, Uchida, & Kitazawa, 2006;Navarra et al., 2005;Vatakis et al., 2008;Vroomen, Keetels, de Gelder, & Bertelson, 2004], and top-down feedback training [Powers et al., 2009;Powers, Hevey, & Wallace, 2012;Schlesinger, Stevenson, Shotwell, & Wallace, 2014;. These latter studies have focused specifically on the TBW. ...
Article
A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses on the relationship between multisensory temporal function and the behavioral, perceptual, and cognitive impairments observed in ASD. Atypical sensory processing is becoming increasingly recognized as a core component of autism, with evidence of atypical processing across a number of sensory modalities. These deviations from typical processing underscore the value of interpreting ASD within a multisensory framework. Furthermore, converging evidence illustrates that these differences in audiovisual processing may be specifically related to temporal processing. This review seeks to bridge the connection between temporal processing and audiovisual perception, and to elaborate on emerging data showing differences in audiovisual temporal function in autism. We also discuss the consequence of such changes, the specific impact on the processing of different classes of audiovisual stimuli (e.g. speech vs. nonspeech, etc.), and the presumptive brain processes and networks underlying audiovisual temporal integration. Finally, possible downstream behavioral implications, and possible remediation strategies are outlined. Autism Res 2015. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
... Changing the location of a multisensory stimulus, which often includes a change in distance from the observer, often leads to changes in effective intensity and its temporal structure. Multisensory integration is established early in life (Bremner et al., 2012;Lewkowicz and Ghazanfar, 2009;Massaro, 1984;Massaro et al., 1986;Neil et al., 2006;Wallace et al., 2006;Wallace and Stein, 1997) and is highly susceptible to the statistics of our perceptual environment (Baier et al., 2006;den Ouden et al., 2009;McIntosh and Gonzalez-Lima, 1998) throughout development (Carriere et al., 2007;Polley et al., 2008;Wallace and Stein, 2007) and even in adulthood (Powers et al., 2012(Powers et al., , , 2009Schlesinger et al., 2014;. Hence, in the real world, multisensory stimuli are specified by their spatial and temporal correlations; correlations that interact with (and that are partly derived from) the relative effectiveness of the stimuli in determining the degree of multisensory facilitation that will be generated. ...
... Suggested remedies have included multisensory training [11] and the use of better mappings of SpO 2 to pitch [4,5,12,13]. Commercial pulse oximeters map linear increments of SpO 2 to either fixed or percentage increments in sound frequency (perceived as pitch); the former results in a linear mapping, whereas the latter results in a logarithmic mapping [14,15]. ...
Article
Our study examined the effectiveness of pulse oximetry sonification enhanced with acoustic tremolo and brightness to help listeners differentiate clinically relevant oxygen saturation ranges. In a series of trials lasting 30 s each, 76 undergraduate participants identified final oxygen saturation range (Target: 100% to 97%; Low: 96% to 90%; Critical: 89% and below), and detected threshold transitions into and out of the target range using conventional sonification (n = 38) or enhanced sonification (n = 38). Median (IQR [range]) accuracy for range identification with the conventional sonification was 80 (70-85 [45-95])%, whereas with the enhanced sonification it was 100 (99-100 [80-100])%; p < 0.001. Accuracy for detecting threshold transitions with the conventional sonification was 60 (50-75 [30-95])%, but with the enhanced sonification it was 100 (95-100 [75-100]%; p < 0.001. Participants can identify clinically meaningful oxygen saturation ranges and detect threshold transitions more accurately with enhanced sonification than with conventional sonification.
... In both audiovisual SJ tasks, individuals' mean responses were calculated at each SOA ( Fig. 1D-E). Individuals' mean responses from SJ tasks were used to calculate a temporal binding window (TBW) using a wellestablished method (Fister et al., 2016;Noel et al., 2016;Schlesinger et al., 2014;Stevenson et al., 2012aStevenson et al., ,b, 2014aStevenson et al., ,b, 2013. Two psychometric sigmoid functions were fit to rates of perceived synchrony across SOAs; one to the audio-first (left) presentations and a second to the visual-first presentations (right). ...
Article
Recent neurobiological accounts of schizophrenia have included an emphasis on changes in sensory processing. These sensory and perceptual deficits can have a cascading effect onto higher-level cognitive processes and clinical symptoms. One form of sensory dysfunction that has been consistently observed in schizophrenia is altered temporal processing. In this study, we investigated temporal processing within and across the auditory and visual modalities in individuals with schizophrenia (SCZ) and age-matched healthy controls. Individuals with SCZ showed auditory and visual temporal processing abnormalities, as well as multisensory temporal processing dysfunction that extended beyond that attributable to unisensory processing dysfunction. Most importantly, these multisensory temporal deficits were associated with the severity of hallucinations. This link between atypical multisensory temporal perception and clinical symptomatology suggests that clinical symptoms of schizophrenia may be at least partly a result of cascading effects from (multi)sensory disturbances. These results are discussed in terms of underlying neural bases and the possible implications for remediation.
... These initial findings suggest the potential of using perceptual training to improve multisensory temporal precision, but it should be noted that such effect seems to be modality-specific (Virsu et al., 2008), and could not be generalized across different levels of stimulus complexity (De Niear et al., 2018). It also remains inconclusive whether narrowing of the TBW in a specific task could benefit other sensory tasks (Schlesinger et al., 2014;Zerr et al., 2019;Powers et al., 2016). Moreover, the modifiability of the TBW shows an asymmetrical pattern, with the visual-leading side appearing more trainable than the auditory-leading side (Cecere et al., 2016;Powers et al., 2009). ...
Article
To integrate auditory and visual signals into a unified percept, the paired stimuli must co-occur within a limited time window known as the Temporal Binding Window (TBW). The width of the TBW, a proxy of audiovisual temporal integration ability, has been found to be correlated with higher-order cognitive and social functions. A comprehensive review of studies investigating audiovisual TBW reveals several findings: (1) a wide range of top-down processes and bottom-up features can modulate the width of the TBW, facilitating adaptation to the changing and multisensory external environment; (2) a large-scale brain network works in coordination to ensure successful detection of audiovisual (a)synchrony; (3) developmentally, audiovisual TBW follows a U-shaped pattern across the lifespan, with a protracted developmental course into late adolescence and rebounding in size again in late life; (4) an enlarged TBW is characteristic of a number of neurodevelopmental disorders; and (5) the TBW is highly flexible via perceptual and musical training. Interventions targeting the TBW may be able to improve multisensory function and ameliorate social communicative symptoms in clinical populations.
... Indeed, remediation focused on temporal processing has been discussed in the literature Stevenson et al., 2014bStevenson et al., , 2014cStevenson et al., , 2015bWallace and Stevenson, 2014). These treatments adapt temporally focused perceptual learning strategies that have been successfully used with TD populations (Powers et al., 2009(Powers et al., , 2012Schlesinger et al., 2014; into an autism-specific remediation. The overall concept is that improved audiovisual temporal processing will have a cascading impact, inducing positive changes in multisensory integration and speech communication Stevenson et al., 2014bStevenson et al., , 2014cStevenson et al., , 2015bWallace and Stevenson, 2014). ...
Article
It has been recently theorized that atypical sensory processing in autism relates to difficulties in social communication. Through a series of tasks concurrently assessing multisensory temporal processes, multisensory integration and speech perception in 76 children with and without autism, we provide the first behavioral evidence of such a link. Temporal processing abilities in children with autism contributed to impairments in speech perception. This relationship was significantly mediated by their abilities to integrate social information across auditory and visual modalities. These data describe the cascading impact of sensory abilities in autism, whereby temporal processing impacts multisensory information of social information, which, in turn, contributes to deficits in speech perception. These relationships were found to be specific to autism, specific to multisensory but not unisensory integration, and specific to the processing of social information.
... Perceptual learning is another measure of plasticity of the TBW. When participants are presented with active feedback about their performance, the TBW narrows, indicating improved temporal precision [23,[78][79][80]. One recent study has implemented such a perceptual-learning task in older adults measuring the TBW with a TOJ task [81••]. ...
Article
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Purpose of review: The integration of information across sensory modalities into unified percepts is a fundamental sensory process upon which a multitude of cognitive processes are based. We review the body of literature exploring aging-related changes in audiovisual integration published over the last five years. Specifically, we review the impact of changes in temporal processing, the influence of the effectiveness of sensory inputs, the role of working memory, and the newer studies of intra-individual variability during these processes. Recent findings: Work in the last five years on bottom-up influences of sensory perception has garnered significant attention. Temporal processing, a driving factors of multisensory integration, has now been shown to decouple with multisensory integration in aging, despite their co-decline with aging. The impact of stimulus effectiveness also changes with age, where older adults show maximal benefit from multisensory gain at high signal-to-noise ratios. Following sensory decline, high working memory capacities have now been shown to be somewhat of a protective factor against age-related declines in audiovisual speech perception, particularly in noise. Finally, newer research is emerging focusing on the general intra-individual variability observed with aging. Summary: Overall, the studies of the past five years have replicated and expanded on previous work that highlights the role of bottom-up sensory changes with aging and their influence on audiovisual integration, as well as the top-down influence of working memory.
... A separate account is derived from recent preliminary evidence suggesting that there may be distinct mechanisms underlying the integration of auditory-and visual-leading multisensory inputs 73 . In this study, participants underwent a perceptual-learning paradigm aimed at narrowing the temporal binding window 27,[74][75][76] . Importantly, this study 73 specifically attempted to manipulate the perception of synchrony on the left (AV) and the right (VA) side of the window independently. ...
Article
Full-text available
Recent empirical evidence suggests that autistic individuals perceive the world differently than their typically-developed peers. One theoretical account, the predictive coding hypothesis, posits that autistic individuals show a decreased reliance on previous perceptual experiences, which may relate to autism symptomatology. We tested this through a well-characterized, audiovisual statistical-learning paradigm in which typically-developed participants were first adapted to consistent temporal relationships between audiovisual stimulus pairs (audio-leading, synchronous, visual-leading) and then performed a simultaneity judgement task with audiovisual stimulus pairs varying in temporal offset from auditory-leading to visual-leading. Following exposure to the visual-leading adaptation phase, participants' perception of synchrony was biased towards visual-leading presentations, reflecting the statistical regularities of their previously experienced environment. Importantly, the strength of adaptation was significantly related to the level of autistic traits that the participant exhibited, measured by the Autism Quotient (AQ). This was specific to the Attention to Detail subscale of the AQ that assesses the perceptual propensity to focus on fine-grain aspects of sensory input at the expense of more integrative perceptions. More severe Attention to Detail was related to weaker adaptation. These results support the predictive coding framework, and suggest that changes in sensory perception commonly reported in autism may contribute to autistic symptomatology.
... Such understanding will allow for the study of timing and binding mechanisms, but most importantly will allow for the development of diagnostic and/or rehabilitation tools. In terms of the latter, given that a number of disorders have been associated with an enlarged twi, Powers, Hillock, and Wallace (2009) showed that perceptual training can change perceived sjs with the change depicting a true perceptual change rather that a short-lived training effect (as shown by a 1 week after-training post-test; see also Powers et al., 2012; see also Schlesinger et al., 2014, for narrowing of the twi with feedback training). Given that we support an association of the different levels of the timing experience, changes of the width of the twi will also lead to temporal discrimination and potentially time estimation changes. ...
Article
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Dementia and delirium are common in medical and surgical inpatients. Neuropsychiatric symptoms can be challenging to manage. Non-pharmacological interventions such as music therapy have been used to manage symptoms in psychiatric hospitals and nursing homes but are not routine in general hospitals. We performed a systematic literature review to establish whether music therapy improves neuropsychiatric symptoms in adults with dementia and/or delirium in the general hospital. We searched CINAHL, Medline and PsycINFO in November 2015. Search terms included music therapy, dementia, delirium. We screened 5054 titles, and read 142 full text articles. None of these met inclusion criteria for our review. To inform future research in music in general hospitals for people with dementia and/or delirium, we qualitatively reviewed 8 articles involving 239 patients. Music delivery was feasible and had a positive effect on some aspects of neuropsychiatric symptoms in various settings, but the studies were generally small, at high risk of bias, and did not use recognized frameworks for evaluating complex interventions. We found no robust published evidence for the use of music therapy in the treatment of neuropsychiatric symptoms in patients with dementia and/or delirium in the general hospital. Well-designed studies of this promising intervention are needed.
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The focus of this chapter is to analyze the characteristics of both post-traumatic stress disorder (PTSD) and post-intensive care syndrome (PICS), discuss the current forms of treatment and therapy for PTSD, and suggest novel behavioral therapies for the treatment of PICS. Two novel therapies, musical therapy and collaborative songwriting, have had previous success in improving the mental and physical health of other vulnerable populations, such as prisoners. A critical aspect of these forms of therapy is understanding the creative processes and benefits of lyrical and non-lyrical composition. Finally, with any form of therapy, it is important to assess their effectiveness, as well as the recovery and functionality of those suffering from PTSD and PICS.
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Speech perception is an inherently multisensory process. When having a face-to-face conversation, a listener not only hears what a speaker is saying, but also sees the articulatory gestures that accompany those sounds. Speech signals in visual and auditory modalities provide complementary information to the listener (Kavanagh and Mattingly, 1974), and when both are perceived in unison, behavioral gains in in speech perception are observed (Sumby and Pollack, 1954). Notably, this benefit is accentuated when speech is perceived in a noisy environment (Sumby and Pollack, 1954). To achieve a behavioral gain from multisensory processing of speech, however, the auditory and visual signals must be perceptually bound into a single, unified percept. The most commonly cited effect that demonstrates perceptual binding in audiovisual speech perception is the McGurk effect (McGurk and MacDonald, 1976), where a listener hears a speaker utter the syllable “ba,” and sees the speaker utter the syllable “ga.” When these two speech signals are perceptually bound, the listener perceives the speaker as having said “da” or “tha,” syllables that are not contained in either of the unisensory signals, resulting in a perceptual binding, or integration, of the speech signals (Calvert and Thesen, 2004).
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The brain's ability to bind incoming auditory and visual stimuli depends critically on the temporal structure of this information. Specifically, there exists a temporal window of audiovisual integration within which stimuli are highly likely to be perceived as part of the same environmental event. Several studies have described the temporal bounds of this window, but few have investigated its malleability. Recently, our laboratory has demonstrated that a perceptual training paradigm is capable of eliciting a 40% narrowing in the width of this window that is stable for at least 1 week after cessation of training. In the current study, we sought to reveal the neural substrates of these changes. Eleven human subjects completed an audiovisual simultaneity judgment training paradigm, immediately before and after which they performed the same task during an event-related 3T fMRI session. The posterior superior temporal sulcus (pSTS) and areas of auditory and visual cortex exhibited robust BOLD decreases following training, and resting state and effective connectivity analyses revealed significant increases in coupling among these cortices after training. These results provide the first evidence of the neural correlates underlying changes in multisensory temporal binding likely representing the substrate for a multisensory temporal binding window.
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Multisensory perception has been the focus of intense investigation in recent years. It is now well-established that crossmodal interactions are ubiquitous in perceptual processing and endow the system with improved precision, accuracy, processing speed, etc. While these findings have shed much light on principles and mechanisms of perception, ultimately it is not very surprising that multiple sources of information provides benefits in performance compared to a single source of information. Here, we argue that the more surprising recent findings are those showing that multisensory experience also influences the subsequent unisensory processing. For example, exposure to auditory-visual stimuli can change the way that auditory or visual stimuli are processed subsequently even in isolation. We review three sets of findings that represent three different types of learning ranging from perceptual learning, to sensory recalibration, to associative learning. In all these cases exposure to multisensory stimuli profoundly influences the subsequent unisensory processing. This diversity of phenomena may suggest that continuous modification of unisensory representations by multisensory relationships may be a general learning strategy employed by the brain.
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An outstanding question in sensory neuroscience is whether the perceived timing of events is mediated by a central supra-modal timing mechanism, or multiple modality-specific systems. We use a perceptual learning paradigm to address this question. Three groups were trained daily for 10 sessions on an auditory, a visual or a combined audiovisual temporal order judgment (TOJ). Groups were pre-tested on a range TOJ tasks within and between their group modality prior to learning so that transfer of any learning from the trained task could be measured by post-testing other tasks. Robust TOJ learning (reduced temporal order discrimination thresholds) occurred for all groups, although auditory learning (dichotic 500/2000 Hz tones) was slightly weaker than visual learning (lateralised grating patches). Crossmodal TOJs also displayed robust learning. Post-testing revealed that improvements in temporal resolution acquired during visual learning transferred within modality to other retinotopic locations and orientations, but not to auditory or crossmodal tasks. Auditory learning did not transfer to visual or crossmodal tasks, and neither did it transfer within audition to another frequency pair. In an interesting asymmetry, crossmodal learning transferred to all visual tasks but not to auditory tasks. Finally, in all conditions, learning to make TOJs for stimulus onsets did not transfer at all to discriminating temporal offsets. These data present a complex picture of timing processes. The lack of transfer between unimodal groups indicates no central supramodal timing process for this task; however, the audiovisual-to-visual transfer cannot be explained without some form of sensory interaction. We propose that auditory learning occurred in frequency-tuned processes in the periphery, precluding interactions with more central visual and audiovisual timing processes. Functionally the patterns of featural transfer suggest that perceptual learning of temporal order may be optimised to object-centered rather than viewer-centered constraints.
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The brain's ability to bind incoming auditory and visual stimuli depends critically on the temporal structure of this information. Specifically, there exists a temporal window of audiovisual integration within which stimuli are highly likely to be bound together and perceived as part of the same environmental event. Several studies have described the temporal bounds of this window, but few have investigated its malleability. Here, the plasticity in the size of this temporal window was investigated using a perceptual learning paradigm in which participants were given feedback during a two-alternative forced choice (2-AFC) audiovisual simultaneity judgment task. Training resulted in a marked (i.e., approximately 40%) narrowing in the size of the window. To rule out the possibility that this narrowing was the result of changes in cognitive biases, a second experiment using a two-interval forced choice (2-IFC) paradigm was undertaken during which participants were instructed to identify a simultaneously presented audiovisual pair presented within one of two intervals. The 2-IFC paradigm resulted in a narrowing that was similar in both degree and dynamics to that using the 2-AFC approach. Together, these results illustrate that different methods of multisensory perceptual training can result in substantial alterations in the circuits underlying the perception of audiovisual simultaneity. These findings suggest a high degree of flexibility in multisensory temporal processing and have important implications for interventional strategies that may be used to ameliorate clinical conditions (e.g., autism, dyslexia) in which multisensory temporal function may be impaired.
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An experiment was conducted to evaluate the effects of localized auditory information on visual target detection performance. Visual targets were presented on either a wide field-of-view dome display or a helmet-mounted display and were accompanied by either localized, nonlocalized, or no auditory information. The addition of localized auditory information resulted in significant increases in target detection performance and significant reductions in workload ratings as compared with conditions in which auditory information was either nonlocalized or absent. Qualitative and quantitative analyses of participants' head motions revealed that the addition of localized auditory information resulted in extremely efficient and consistent search strategies. Implications for the development and design of multisensory virtual environments are discussed. Actual or potential applications of this research include the use of spatial auditory displays to augment visual information presented in helmet-mounted displays, thereby leading to increases in performance efficiency, reductions in physical and mental workload, and enhanced spatial awareness of objects in the environment.
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Manual reaction times to visual, auditory, and tactile stimuli presented simultaneously, or with a delay, were measured to test for multisensory interaction effects in a simple detection task with redundant signals. Responses to trimodal stimulus combinations were faster than those to bimodal combinations, which in turn were faster than reactions to unimodal stimuli. Response enhancement increased with decreasing auditory and tactile stimulus intensity and was a U-shaped function of stimulus onset asynchrony. Distribution inequality tests indicated that the multisensory interaction effects were larger than predicted by separate activation models, including the difference between bimodal and trimodal response facilitation. The results are discussed with respect to previous findings in a focused attention task and are compared with multisensory integration rules observed in bimodal and trimodal superior colliculus neurons in the cat and monkey.
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Recent studies have demonstrated that dyslexia is associated with deficits in the temporal encoding of sensory information. While most previous studies have focused on information processing within a single sensory modality, it is clear that the deficits seen in dyslexia span multiple sensory systems. Surprisingly, although the development of linguistic proficiency involves the rapid and accurate integration of auditory and visual cues, the capacity of dyslexic individuals to integrate information between the different senses has not been systematically examined. To test this, we studied the effects of task-irrelevant auditory information on the performance of a visual temporal-order-judgment (TOJ) task. Dyslexic subjects' performance differed significantly from that of control subjects, specifically in that they integrated the auditory and visual information over longer temporal intervals. Such a result suggests an extended temporal "window" for binding visual and auditory cues in dyslexic individuals. The potential deleterious effects of this finding for rapid multisensory processes such as reading are discussed.
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Judgments of the intensity of a stimulus are dependent on the level of central nervous system activity it generates. Generally, it is assumed that such judgments are based on activity along modality-specific pathways. Thus, visual intensity judgments would be based on unimodal visual activity. However, many neurons do not fit neatly within modality-specific categories, but can be influenced by more than one sensory modality. Often the multisensory effect is quite pronounced. If these multisensory neurons participate in such fundamental functions as perceived intensity, the presence of a nonvisual (i.e., auditory) cue may have a significant effect on the perceived intensity of a visual cue. The results of the present study were consistent with such a hypothesis. A brief, broad-band auditory stimulus was found to significantly enhance the perceived intensity of an LED. The effect was most pronounced at the lowest visual intensities, and was evident regardless of the location of the auditory cue. However, it was present only at the location of visual fixation. Yet, despite the significant influence of the auditory cue, and its differential effect at different visual intensities, a power function that maintains the proportionality among perceived visual intensities was retained.
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The importance of multisensory integration for human behavior and perception is well documented, as is the impact that temporal synchrony has on driving such integration. Thus, the more temporally coincident two sensory inputs from different modalities are, the more likely they will be perceptually bound. This temporal integration process is captured by the construct of the temporal binding window-the range of temporal offsets within which an individual is able to perceptually bind inputs across sensory modalities. Recent work has shown that this window is malleable and can be narrowed via a multisensory perceptual feedback training process. In the current study, we seek to extend this by examining the malleability of the multisensory temporal binding window through changes in unisensory experience. Specifically, we measured the ability of visual perceptual feedback training to induce changes in the multisensory temporal binding window. Visual perceptual training with feedback successfully improved temporal visual processing, and more importantly, this visual training increased the temporal precision across modalities, which manifested as a narrowing of the multisensory temporal binding window. These results are the first to establish the ability of unisensory temporal training to modulate multisensory temporal processes, findings that can provide mechanistic insights into multisensory integration and which may have a host of practical applications.
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Background: Anesthesiology requires performing visually oriented procedures while monitoring auditory information about a patient's vital signs. A concern in operating room environments is the amount of competing information and the effects that divided attention has on patient monitoring, such as detecting auditory changes in arterial oxygen saturation via pulse oximetry. Methods: The authors measured the impact of visual attentional load and auditory background noise on the ability of anesthesia residents to monitor the pulse oximeter auditory display in a laboratory setting. Accuracies and response times were recorded reflecting anesthesiologists' abilities to detect changes in oxygen saturation across three levels of visual attention in quiet and with noise. Results: Results show that visual attentional load substantially affects the ability to detect changes in oxygen saturation concentrations conveyed by auditory cues signaling 99 and 98% saturation. These effects are compounded by auditory noise, up to a 17% decline in performance. These deficits are seen in the ability to accurately detect a change in oxygen saturation and in speed of response. Conclusions: Most anesthesia accidents are initiated by small errors that cascade into serious events. Lack of monitor vigilance and inattention are two of the more commonly cited factors. Reducing such errors is thus a priority for improving patient safety. Specifically, efforts to reduce distractors and decrease background noise should be considered during induction and emergence, periods of especially high risk, when anesthesiologists has to attend to many tasks and are thus susceptible to error.
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In natural environments, human sensory systems work in a coordinated and integrated manner to perceive and respond to external events. Previous research has shown that the spatial and temporal relationships of sensory signals are paramount in determining how information is integrated across sensory modalities, but in ecologically plausible settings, these factors are not independent. In the current study, we provide a novel exploration of the impact on behavioral performance for systematic manipulations of the spatial location and temporal synchrony of a visual-auditory stimulus pair. Simple auditory and visual stimuli were presented across a range of spatial locations and stimulus onset asynchronies (SOAs), and participants performed both a spatial localization and simultaneity judgment task. Response times in localizing paired visual-auditory stimuli were slower in the periphery and at larger SOAs, but most importantly, an interaction was found between the two factors, in which the effect of SOA was greater in peripheral as opposed to central locations. Simultaneity judgments also revealed a novel interaction between space and time: individuals were more likely to judge stimuli as synchronous when occurring in the periphery at large SOAs. The results of this study provide novel insights into (a) how the speed of spatial localization of an audiovisual stimulus is affected by location and temporal coincidence and the interaction between these two factors and (b) how the location of a multisensory stimulus impacts judgments concerning the temporal relationship of the paired stimuli. These findings provide strong evidence for a complex interdependency between spatial location and temporal structure in determining the ultimate behavioral and perceptual outcome associated with a paired multisensory (i.e., visual-auditory) stimulus.
Article
Human multisensory systems are known to bind inputs from the different sensory modalities into a unified percept, a process that leads to measurable behavioral benefits. This integrative process can be observed through multisensory illusions, including the McGurk effect and the sound-induced flash illusion, both of which demonstrate the ability of one sensory modality to modulate perception in a second modality. Such multisensory integration is highly dependent upon the temporal relationship of the different sensory inputs, with perceptual binding occurring within a limited range of asynchronies known as the temporal binding window (TBW). Previous studies have shown that this window is highly variable across individuals, but it is unclear how these variations in the TBW relate to an individual's ability to integrate multisensory cues. Here we provide evidence linking individual differences in multisensory temporal processes to differences in the individual's audiovisual integration of illusory stimuli. Our data provide strong evidence that the temporal processing of multiple sensory signals and the merging of multiple signals into a single, unified perception, are highly related. Specifically, the width of right side of an individuals' TBW, where the auditory stimulus follows the visual, is significantly correlated with the strength of illusory percepts, as indexed via both an increase in the strength of binding synchronous sensory signals and in an improvement in correctly dissociating asynchronous signals. These findings are discussed in terms of their possible neurobiological basis, relevance to the development of sensory integration, and possible importance for clinical conditions in which there is growing evidence that multisensory integration is compromised. (PsycINFO Database Record (c) 2012 APA, all rights reserved).
Article
A modified critical-incident analysis technique was used in a retrospective examination of the characteristics of human error and equipment failure in anesthetic practice. The objective was to uncover patterns of frequently occurring incidents that are in need of careful prospective investigation. Forty-seven interviews were conducted with staff and resident anesthesiologists at one urban teaching institution, and descriptions of 359 preventable incidents were obtained. Twenty-three categories of details from these descriptions were subjected to computer-aided analysis for trends and patterns. Most of the preventable incidents involved human error (82 per cent), with breathing-circuit disconnections, inadvertent changes in gas flow, and drug-syringe errors being frequent problems. Overt equipment failures constituted only 14 per cent of the total number of preventable incidents, but equipment design was indictable in many categories of human error, as were inadequate experience and insufficient familiarity with equipment or with the specific surgical procedure. Other factors frequently associated with incidents were inadequate communication among personnel, haste or lack of precaution, and distraction. Results from multi-hospital studies based on the methodology developed could be used for more objective determination of priorities and planning of specific investments for decreasing the risk associated with anesthesia.
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Workload is an important determinant of human performance during complex dynamic tasks. We indirectly measured the mental workload of nine anesthesia residents during 19 cases using a secondary (subsidiary) task paradigm in which performance on an extra task (problems in mathematical addition occurring approximately every 45 s) was used as a probe of a subject's "spare capacity." Excess response time (above baseline) correlated with activities like "manual task" and "speaking with the attending anesthesiologist." The addition problem was either skipped or had a high excess response time (greater than 30 s) in 40% of presentations. The complexity of a case and the experience level of the resident interacted in determining the workload. Subjective workload ratings confirmed that induction of and emergence from anesthesia were periods of highest workload, with "attention" as the dominant cognitive requirement. The anesthesiologist's spare capacity may often be limited during anesthesia. These types of workload measurement techniques should be applied in controlled studies to better define the factors that increase workload.
Article
While adverse outcomes linked to anesthesia are uncommon in healthy patients, they do occasionally happen. There is rarely a single cause. Anesthesia and surgery bring the patient into a complex world in which innumerable small failings can converge to produce an eventual catastrophe. And for all the technology involved, the anesthesiologist remains the cornerstone of safe anesthesia care, protecting the patient from harm regardless of its source. Responding to the demands of the operating room environment requires on-the-spot decision making in a complex, uncertain, and risky setting. Only responsible, professional human beings acting in concert can perform this task; no machine that we devise now or in the foreseeable future will suffice. I have outlined the components of a dynamic decision-making process that successfully protects patients in almost all cases. However, being human, anesthesiologists do make errors along the way--errors we are just beginning to understand. Sometimes these errors are due to faulty vigilance or incompetence, but usually they are made by appropriately trained, competent practitioners. Anesthesiologists can err in many ways, and recognizing these ways makes it easier to analyze the events leading to an anesthetic accident. More importantly, it better equips us to eliminate or minimize them in the future--and this is the real challenge.
Article
Simulation is used extensively in industries that involve routine, but risky activities. The authors describe an anesthesia simulation environment that provides a re-creation of the anesthesiologist's task environment in a real operating room. The system provides appropriate inputs to standard monitoring equipment in common use during anesthesia, including ECG (with arrhythmias); invasive systemic arterial, pulmonary arterial, and central venous pressures (all coupled to ECG arrhythmias); automated cuff blood pressure; pulse oximetry; mass spectrometry; breathing circuit spirometry; and oxygen analysis. An intubation/thorax mannequin allows tracheal intubation and tube manipulation, and provides for simulation of occlusion, malposition, or disconnection of the tracheal tube, as well as regurgitation of gastric contents. The simulation is comprehensive in that it is "hands-on" and requires actual performance of most interventions using actual equipment. The simulation is conducted by a systems operator and a simulation director; the latter also acts in the roles of surgeon and circulating nurse. The simulator outputs are determined by a "script" that defines the consequences of routine anesthetic actions and pre-established critical incidents. Decisions about timing and override of the script are made by the simulation director. This control system offers maximum flexibility while maintaining clinical realism. The simulator experiences were judged as highly realistic by 21 subjects. Limitations in this version have centered on the mannequin (e.g., no patient movement, minimal or confusing physical signs) and will be addressed in future versions of the system. The authors suggest that anesthesia simulation can be accomplished at nominal expense and has major potential for training, continuing education, certification, and research.
Article
Adaptations of the critical-incident technique were used to gather reports of anesthesia-related human error and equipment failure. A total of 139 anesthesiologists, residents, and nurse-anesthetists from four hospitals participated as subjects in directed or open-ended interviews, and 48 of them functioned as "trained observers." A total of 1,089 descriptions of preventable "critical incidents" were collected. Of these, 70 represented errors or failures that had contributed in some way to a "substantive negative outcome." From these incidents, ten potential strategies were developed for prevention or detection of incidents. Overall patterns observed in this wider study were similar to those of our earlier report. The incidents most frequently reported included breathing circuit disconnections, drug-syringe swaps, gas-flow control errors and losses of gas supply. Only 4% of the incidents with substantive negative outcomes involved equipment failure, confirming the previous impression that human error is the dominant issue in anesthesia mishaps. Among the broad categories of key strategies for mishap prevention were additional technical training, improved supervision, improved organization, equipment human-factors improvements, and use of additional monitoring instrumentation. The data also suggest that less healthy patients are more likely to be affected adversely by errors. It is suggested that, in future studies of anesthesia mortality and morbidity, untoward events should be classified according to preventive strategy rather than outcome alone as an aid to those who wish to apply the experience of others to lessen the risk in their individual practice.
Article
Anesthesia residents take longer to detect changes in electronically monitored data during the induction phase of anesthesia during the maintenance phase. This study was performed to investigate the reasons for this delay and to validate a method of measuring vigilance. The activity of ten residents was studied during 73 surgical procedures. Data were collected during three 15-min periods from each case: induction, starting with application of the electrocardiograph; maintenance, an arbitrary period between induction and emergence; and emergence, ending with detachment of the electrocardiograph. Vigilance was measured as the time taken to detect a change, from normal to abnormal, of an artificial parameter displayed on the physiologic monitor (response time). An observer simultaneously recorded each time that the resident looked toward the monitors. Vigilance to the monitor display was less during induction and emergence than during maintenance (P < 0.005). Residents spent less total time watching monitors during induction than during maintenance (P < 0.005), and the duration of each monitor observation was shorter (P < 0.0005). Anesthesia residents usually looked at the monitors several times before detecting the abnormal value. The measure of anesthesia vigilance correlated with independent measures of monitor watching time and frequency. The results suggest that during induction of anesthesia, which is a period of high anesthesiologist workload, residents glance toward monitors to gather data rather than scan displays. The results help to validate the method for measuring anesthesia vigilance.
Article
Two approaches to the problem of human fallibility exist: the person and the system approaches. The person approach focuses on the errors of individuals, blaming them for forgetfulness, inattention, or moral weakness. The system approach concentrates on the conditions under which individuals work and tries to build defences to avert errors or mitigate their effects. High reliability organisations - which have less than their fair share of accidents - recognise that human variability is a force to harness in averting errors, but they work hard to focus that variability and are constantly preoccupied with the possibility of failure.
Article
The ventral form vision pathway of the primate brain comprises a sequence of areas that include V1, V2, V4 and the inferior temporal cortex (IT) [1]. Although contour extraction in the V1 area and responses to complex images, such as faces, in the IT have been studied extensively, much less is known about shape extraction at intermediate cortical levels such as V4. Here, we used functional magnetic resonance imaging (fMRI) to demonstrate that the human V4 is more strongly activated by concentric and radial patterns than by conventional sinusoidal gratings. This is consistent with global pooling of local V1 orientations to extract concentric and radial shape information in V4. Furthermore, concentric patterns were found to be effective in activating the fusiform face area. These findings support recent psychophysical [2,3] and physiological [4,5] data indicating that analysis of concentric and radial structure represents an important aspect of processing at intermediate levels of form vision.
Article
Physiological and behavioral studies in animal models have revealed that information from the different senses can be used synergistically to enhance the detection of objects and events. Although a great deal of evidence exists which demonstrates the synergistic use of multisensory cues in human behavior and perception, there is conflicting evidence about whether such interactions can be used to aid in stimulus detection. To examine this issue, we had volunteers indicate the presence or absence of a brief, low-intensity sound that was either presented alone or paired with a simultaneous light in a one-interval signal detection task. In the first experiment, the task-irrelevant light was found to enhance the detectability of the sound, but also to increase the subject's willingness to report the presence of a sound (i.e., response bias). In the second experiment, designed to eliminate this response bias, we found an improvement in stimulus detectability in the absence of any change in bias. These findings demonstrate the presence of a significant multisensory-mediated gain in stimulus detection in human subjects.
Article
An experiment is reported in which reaction times (RTs) were measured to light and sound presented singly and in combination. The chief experimental variable was stimulus onset asynchrony. The results may be summarized as follows: (a) Intersensory facilitation was demonstrated in that, for certain asynchronies, RTs were faster to the combination than to either stimulus alone. (b) Maximum facilitation occurred at or just beyond the point at which the asynchrony was equal to the difference in RT to the single stimuli. (c) Varying the intensity of the stimuli differentially affected the magnitude of facilitation. Reducing the light intensity resulted in less facilitation whereas reducing the sound intensity had no effect.
Article
Unlabelled: In this study, we sought to examine several measures of anesthesia provider workload during different phases of anesthesia care and during teaching and nonteaching cases. Clinical work was assessed in real-time during 24 general anesthetics performed by consenting anesthesia providers. Workload was measured using physiological (provider heart rate), psychological (self-assessment and observer rating), and procedural (response latency to an alarm light and workload density) techniques. Clinicians' heart rates, observer and self-reported workload scores, and nonteaching workload density were consistently increased during anesthetic induction and emergence compared with maintenance. In nonteaching cases, workload density correlated with heart rate and with psychological workload. Workload density during teaching cases did not decrease during the induction and was significantly greater than during nonteaching cases. Alarm-light response latency (a measure of clinical vigilance) was significantly prolonged during the teaching compared with nonteaching cases. These results suggest that intraoperative teaching increases the workload of the clinician instructor and may reduce vigilance during anesthesia care. Additionally, multiple workload measures may provide a more comprehensive profile of the work demands of clinical cases. Implications: Psychological, physiological, and procedural workload measures during routine general anesthesia cases documented the increased work demands of induction and emergence. Intraoperative teaching increased workload and decreased vigilance, suggesting the need for caution when educating during patient care.
Article
If an anthropologist were to stumble into this room between 6 and 8 p.m. this evening, he might find the telltale signs of a ritual: a group of residents and interns huddled around a table, scribbling hieroglyphics on scraps of paper. (Figure) To a physician, this scenario is all too familiar — we call it “sign-out” — but in a way, the anthropologist would be right: it is a peculiar ritual, this daily transfer of patients from one medical team to another. As I write this, at the end of a frantic afternoon, 18 residents are simultaneously handing off . . .
A comprehensive anesthesia simulation environment: re-creating the operating room for research and training.
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