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Activity Number:
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471
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Type:
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Contributed
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Date/Time:
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Wednesday, August 1, 2007 : 2:00 PM to 3:50 PM
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Sponsor:
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Biopharmaceutical Section
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| Abstract - #309255 |
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Title:
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Using Latent Sleepiness To Evaluate an Important Side Effect of Promethazine
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Author(s):
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Alan Feiveson*+ and Matthew Hayat and Zalman Vaksman and Lakshmi Putcha and Jason L. Boyd
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Companies:
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National Aeronautics and Space Administration and National Aeronautics and Space Administration and Wyeth and National Aeronautics and Space Administration and National Aeronautics and Space Administration
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Address:
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Johnson Space Center, Houston, TX, 77058,
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Keywords:
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latent variable ; instrumental variable ; sleepiness score ; drug concentration ; cognitive performance
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Abstract:
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Astronauts often use promethazine (PMZ) to counteract space motion sickness; however PMZ may cause drowsiness, which might impair cognitive function. In a NASA ground study, subjects received PMZ and performed several cognitive tests during the drug metabolization period. Subjects also reported sleepiness using the Karolinska Sleepiness Score (KSS), which ranges from 1 - 9. A problem arises when using KSS to establish an association between true sleepiness and performance because KSS scores tend to overly concentrate on the values 3 ("fairly awake") and 7 ("moderately tired"). Therefore, we defined a "latent" sleepiness measure as a continuous random variable describing a subject's actual, but unobserved true state of sleepiness through time. The latent sleepiness and observed KSS were associated in a conditional probability model to permit unbiased comparison of performance measures.
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