Event-based detection of lapses of responsiveness Peiris, Malik T. R.; Jones, Richard D.; Davidson, Paul R. ...
2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society,
01/2008, Letnik:
2008
Conference Proceeding, Journal Article
EEG spectral power has been shown to correlate with level of arousal and alertness in humans. In this paper, we assess its usefulness in the detection of lapses of responsiveness ('lapses') on an ...event, rather than state, basis. Eight non-sleep-deprived normal subjects performed two 1-hour sessions of a continuous tracking task while EEG and facial video were recorded. Lapses were identified by the presence of tracking flat spots or clear instances of behavioural microsleeps as identified by a human rater observing video recordings of the subject. Spectral power in the standard EEG bands was calculated using the Burg method on 16 bipolar derivations to form an EEG feature matrix. Linear discriminant analysis was used to form a classifier for each subject. The 8 classifiers were combined using stacked generalization with constrained-least squares fitting to create an overall detection model. Estimation of lapse-event detection performance required the development of a novel procedure to account for the variable duration of lapses. Event detection for the concatenated data from all 8 subjects yielded an overall sensitivity of 73.5%, selectivity of 25.5%, and accuracy of 61.2%. While the performance of this detector is modest, and not yet sufficient for real-time detection, the detection of lapses at such a high temporal resolution (1 s) is encouraging relative to previous studies which have generally tended to estimate changes in alertness on a minute-scale basis.
In many high-risk occupations, it is critical that a person remains alert at all times. There is much to be gained by being able to monitor a person on-line and detect lapses of consciousness (LoC) ...so that remedial action can be taken (e.g., a rest break) to ensure that safety is maintained. In this study, 15 normal subjects were observed on two sessions while they performed a continuous tracking task for a period of 1 hour. EEG, eye movements, tracking performance data and a video of the subject were recorded during the session. This work presents some preliminary results on the phenomenon of lapsing. Only 4 of the 15 subjects did not have a LoC at some stage. Seven subjects had LoCs more than 45 times and 4 more than 100 times during the 2 hours. The mean rate of lapsing over all subjects was 29.1 LoC/h. In contrast, lapses in performance were caused by both lapses of consciousness (30.1%) and attention (69.9%). There was no correlation found between age of subject and number of lapses of consciousness.
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