MEASURING SLEEP DEPRIVATION WHEN TYPE II ERRORS MAY LEAD TO DANGEROUS CONCLUSIONS

• Published in: Aviation, space, and environmental medicine space, and environmental medicine, 2012-03, Vol.83 (3), p.273a-273a
• Main Authors: Nemeth, K, Quill, L, Arbuckle, N
• Format: Article
• Language: English
• ISSN: 0095-6562

INTRODUCTION: Sleep deprivation reduces cognitive function and may impair one's ability to perform in a safe and effective manner. Furthermore, when operator errors can lead to catastrophic events, such as piloting aircraft or treating patients, shifts often last longer than 24 hours. This potentially dangerous combination has spurred research into the potential for predicting fatigue vulnerable individuals by using cognitive tests applied throughout a period of sleep deprivation; however, this method is intrusive, and takes significant time during data collection, and participant recruitment. These difficulties motivate research into the possible use of medical imaging technologies where researchers can collect a snapshot of brain activation to predict and visualize fatigue vulnerability. METHODS: Our team prepared a two stage study which first evaluated military personnel in a controlled 30hr sleep deprivation period. Participants were monitored to ensure that they did not nap, consume caffeine, or other stimulants. The second phase of the study used medical residents during their normal extended shift work conditions. Participants kept a log, wore an activity monitor, and were allowed to consume stimulants and take naps when time permitted. An fMRI was conducted at the beginning and end of the sleep deprivation period in both studies. RESULTS: The results of the two studies were markedly different. In the lab study, vulnerable participants were clearly identified by a significant drop in cognitive performance using an alpha=.05. Using this same criteria the naturalistic study of medical residents, showed no drop in performance. DISCUSSION: Could the lack of power in the naturalistic study, lead to the dangerous decision that fatigue does not affect cognitive functioning after 30 hours of alertness? Is it truly possible that 14 randomly selected residents were capable of maintaining alert behavior for 30+ hours without a drop in performance? This paper will discuss the potential for Type II errors. Small samples in each study, the lack of control of behavior in the second study, and the significant danger of concluding continued human performance at 30 hours is "safe" requires us to investigate conclusions from this study further.