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Articles: Pierre Philip, Jacques Taillard, Nicholas Moore, Sandrine Delord, Cédric Valtat, Patricia Sagaspe, and Bernard Bioulac The Effects of Coffee and Napping on Nighttime Highway Driving: A Randomized Trial Ann Intern Med 2006; 144: 785-791 [Abstract] [Full text] [PDF]

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Other factors explaining nighttime driving performance

Andrew J. Yee   (13 June 2006)

In response

Chakrapani Prakash   (7 June 2006)

Other factors explaining nighttime driving performance 13 June 2006
Andrew J. Yee, MD Massachusetts General Hospital Cancer Center, Boston, MA Send rapid response to journal: Re: Other factors explaining nighttime driving performance yee{at}post.harvard.edu Andrew J. Yee	Philip and colleagues (1) have validated the conventional wisdom that coffee and napping improve nighttime highway driving performance with their real-life study. Their study raises several questions. First, an alternative factor affecting the ability to drive at night is nighttime visual acuity. One of the twelve study participants (participant number 7) was egregiously the worst under all three nighttime test conditions: 13 line crossings with coffee (3.1 SD worse than the mean), 17 line crossings with placebo (1.8 SD worse than the mean), and 8 line crossings with napping (2.0 SD worse than the mean). In contrast, during the day, his driving ability was comparable to the rest of the test subjects. Cataract disease, retinitis pigmentosa, and vitamin A deficiency are several conditions that may decrease nighttime visual acuity. While these disorders would certainly be highly unusual in a young healthy male and while there may be a large range in what is considered "normal" driving ability, it may be of interest to exclude these conditions as factors, given this participant’s consistently poor performance, rather than attributing it to simply fatigue. Nevertheless, when this driver is excluded from the analysis, an informal analysis of the remaining 11 subjects using paired t-tests with Bonferroni correction for multiple comparisons yields findings similar to the overall conclusions of the trial. Secondly, while the number of line crossings may be viewed as a proxy for driving performance, it would be of interest to know how many times the professional copilot had to intervene as a consequence. While potentially subjective, this may better capture the relevance of each line crossing, especially since the participants were instructed to drive at high speeds averaging 80 miles per hour. Finally, it would informative to know what measures the professional copilot driver used to stay awake for the study. Napping, coffee, or another intervention, like modafinil? References 1. Philip P, Taillard J, Moore N, et al. The effects of coffee and napping on nighttime highway driving: a randomized trial. Ann Intern Med. 2006;144(11):785-91. Conflict of Interest: None declared
In response 7 June 2006
Chakrapani Prakash, MD, FACP Community Medical Center, Toms River, NJ 08755 Send rapid response to journal: Re: In response chak811{at}yahoo.com Chakrapani Prakash	A physician who practices in today's environment, is likely to work with physician extenders like very qualified RNs, Physician's Assistants and Hopsitalists. The demands for 'scut work' are less in real world than in an Intern's world. A realistic test would be to challenge them with 'panic numbers' like abnormal electrolytes, arterial blood gases, coagulopathies; or abnormal X rays like free air in the abdomen, or pneumothorax or abnormal EKG; after 24 -36 hours of sleep deprivation, since these are typically the issues that the tired future Intern will likely face at 2 am when he is on ER call for his group. I will certainly favor a mid-day 'power nap' of 15 minutes to recharge the batteries. Chakrapani Prakash, MD FACP Conflict of Interest: None declared