Methods: In order to identify whether the brain finds certain CTG patterns more difficult to interpret, thus influencing information bias and level of confidence (Davis, Edgar & Catherwood, in press) and result from flipping from rule based decision-making to the heuristic style (De Neys, W., Vartanian, O. & Goel, V. 2008) two experiments were developed using e-prime and CTG trace patterns produced during labour (NICE, 2008). Two experiments have been run: Experiment 1FHR as the only datum line; Experiment 2 FHR and maternal contractions datum lines. Key features, such as FHR variability and decelerations, were extracted and placed on slides. A short training session was built into the front end of the programme. A fixation slide was followed by slides showing different features. The participants, general population, were asked whether, for example, accelerations were present (true/false) followed by a slide asking for a confidence scale of one to four how certain they were that the statement was true/false. Experiment 1 (n = 81) had 20 slides randomly presented for 60 cycles, experiment 2 (n = 38) had 18 slides randomly presented for 38 cycles.
Results: Most errors were made when identifying accelerations and decelerations in experiment 1 - deceleration error (true 2.79%, false 25.1%) (figure 1) experiment 2- deceleration errors (true 9.23%, false 3.49%). Eye scanning patterns might be selective based on information bias and there is a suggestion that as the error rate increases, situation awareness decreases, information bias remains high and the level of confidence also remains high. Further analysis is ongoing. A third experiment with health care professionals using SmartEyePro and EEG is in process in order see if the same patterns are difficult to identify, their eye scan patterns and decision strategies. This will inform training and operational procedures when using the CTG for foetal monitoring.
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