Janet Anderson, Penelope Sanderson and Michael Norris

1. The Role of Auditory Attention and Auditory Perception in the Design of Real-time Sonification of Anaesthesia Variables Janet Anderson, Penelope Sanderson and Michael Norris ARC Key Centre for Human Factors and Applied Cognitive Psychology University of Queensland St. Lucia, Brisbane, Australia

2. Anaesthesia domain • Domain characteristics (Cook and Woods, 1996) • Safety critical • Dynamic • Early detection is vital • Individual differences • Multiple causes of problems • Multiple possible interventions • Competing goals and attentional demands

3. Anaesthesia domain • Attentional problems: • large amount of information • competing demands on attention (Blike, Jensen, Whalen & Surgenor, 2000; Moll van Charante et al., 1993; Seagull & Sanderson, 2001). • evidence that when workload is high clinicians fixate on problems, ignore relevant cues and are distracted by irrelevant cues (Gaba & Howard, 1995; Williamson, Webb, Sellen, Runciman & van der Walt, 1993). • Appropriate control of attention is a human-system problem

4. Sonification benefits • Sonification of data is a possible solution for attention allocation problems (Woods, 1995, Seagull et al. 2000, Xiao et al. 2000, Watson et al. 2000). • Visual attention not required • Pre-attentive monitoring provides continuous link with the data • Reduce need for alarms • Early detection of problems

5. Sonification – current status Pulse oximetry: A successful physiological sonification • Single sound stream of beeps • Rate of beeps = heart rate • Pitch of beeps = oxygen saturation AIMS study: • Highly recommended for intra-operative monitoring • Detected 27% of all incidents • Detected 87% of cases of endobronchial intubation Runciman et al. (1993).

6. Sonification challenges • How to design a sonification to appropriately control attention? • Absence of design guidelines (Kramer et al. 1999). • Limits of acoustic parameters • Human perceptual limits • Demands of the domain

7. Sonification challenges • How many streams and dimensions can be monitored? • How long do attentional shifts within streams and between streams take? • How can selective and divided attention be supported?

8. Unresolved questions • Answers not provided by: • Dichotic listening studies (Cherry, 1953, Broadbent, 1958, Treisman 1964, Neisser, 1966, Moray, 1959) • Auditory cueing studies (Mondor & Bregman, 1994, Mondor, Zatorre & Terrio, 1998, Mondor & Zatorre, 1995) • FIT studies of auditory stimuli (Thompson, 1994, Hall et al, 2000, Thompson, Hall & Pressing, 2001) • Auditory Scene Analysis (Bregman, 1990)

9. Unresolved questions • Stimulus perspective • What is the optimal stimulus organization? • What effect does stimulus organization have on selective and divided attention? • One stream, six variables • Two streams, three variables in each • Three streams, two variables in each

10. Aims of studies • Evaluate the feasibility of a single stream auditory display of six physiological variables. • Compare the discriminability of the mappings used in Study one and Study two. • Assess perceptual interactions between acoustic parameters.

11. Study design • Two factors • Acoustic dimension – 6 levels • Distractors – 3 levels • No distractor • One distractor • Five distractors • Within subjects • Participants n=11

12. Method • Pulsing sound stream with six changing auditory dimensions: • Frequency • Amplitude • Pulse speed • Tremolo

13. Method • Timbre – study one – harmonics - study two - formants • Pulse width – study one discrete - study two continuous

14. Method

15. Results

16. Results – 1,2,3 streams

17. Future directions • Operation of selective and divided attention with the 1,2 and 3 stream configurations • Examine the role of domain expertise by introducing meaningful data

18. Six dimensional visual display(Marey, from Tufte, 1983)