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Cognitive performance test for detecting sleepiness-induced impairment.
Heitmann-A; Holzbrecher-M; Schnipke-D
Sleep 2008 Jun; 31(Abstract Suppl):A339
Introduction: The detection of dangerous impairment levels induced by poor or insufficient sleep can be of benefit in certain situations, such as the screening of workers with safety-critical jobs. The present study was conducted to evaluate a new cognitive performance test as a potential tool for impairment detection. The BLT test (developed by Bowles-Langley Technologies, Inc.) is a brief, simple computerized shape recognition test that requires the user to make a Yes/No decision about whether all items in a given screen are the same. After a series of 50 screens the resulting speed/accuracy-based score is compared to the user's baseline. Methods: Fifteen subjects (aged 25-50 years) participated in a sleep restriction study. They stayed in the lab for two consecutive days and nights and were only allowed to sleep for three hours in the morning before the second test day. On each test day, they completed ten bi-hourly test sessions (starting at 1200). Each test session included several subjective tests (e.g., Visual Analog Scales, Thayer Activation-Deactivation Adjective Checklist, Karolinska Sleepiness Scale), 5-min simple reaction time test (PVT), 25-min driving simulation task, 50-screen four-choice reaction time test, and four shape recognition tests (SRT). Results: The various test-bed measures (subjective tests, PVT, four-choice test and driving task) showed the expected circadian trend with consistently impaired levels at night. SRT scores were significantly lower at night (0200, 0400, 0600) as compared to the two highest-score test sessions of the same test day (paired t-tests). On the group level, the SRT score (standard scoring algorithm 1.0) correlated well with many of the test--bed measures (Spearman R>0.8, separate analysis for each test day). However, on the individual level, correlations were less strong and varied greatly between subjects. Conclusion: The aim of further analysis is to refine the SRT scoring algorithm in order to improve the intra-individual correlations between the score of the shape recognition test and other test-bed measures, and to define impairment thresholds
Sleep-deprivation; Sleep-disorders; Shift-work; Circadian-rhythms; Psychomotor-function; Humans; Men; Women; Analytical-processes; Age-groups; Laboratory-testing
Bowles-Langley Technology, Inc.
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Content source: National Institute for Occupational Safety and Health Education and Information Division