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Modafinil attenuates the decline in frontal lobe function during simulated night shift.

Randazzo AC; Schweitzer PK; Stone KL; Walsh JK
Sleep 2003 Jun; 26(Abstract Suppl):A82
Introduction: Reduced alertness during night shift and the associated risk of errors and impaired performance remains an intractable problem for many industries and occupations. Therefore, we studied the effects of the alerting drug modafinil (MOD) on executive function during usual night shift hours in a simulated shift work protocol. Methods: 32 subjects (15 male, 17 female; mean age 31.5; range 18-55) participated in a parallel groups, double-blind, repeated measures design. Written informed consent was obtained. All subjects were free of medical and psychiatric disorders, kept a regular sleep schedule, habitually consumed < 10 alcoholic drinks/week and < 400mg caffeine/ day, and did not take CNS active medications. A standard PSG adapted subjects to laboratory procedures and excluded those with sleep disorders. Adaytime MSLT excluded individuals with a mean latency of < 5 minutes. Prior to randomization, subjects were trained on performance tests and maintained a regular sleep wake schedule. Either MOD 200mg or placebo (PBO) was given at 2200 hours each night during a 4- night/4-day simulated night shift schedule. From 2300 until approximately 0700 each night, subjects engaged in a variety of performance tests, alertness measures and a cognitive testing battery. This report includes results for the cognitive testing battery. Tests included were the Wisconsin Card Sorting Test (WCST), Torrance Tests of Creative Thinking- Verbal (TTCT-V) and Figural (TTCT-F), Category Test (CT), Optimal Telegram (OT), Anagrams, Thurstone Word Fluency (TWF), Sentence Completion (SC), and Letter Number Sequencing (LNS). MANOVAs on the difference scores between baseline and treatment were used to analyze TTCT-V and TTCT-F variables. MANOVAs were conducted on the WCST, OT, CT variables. T-tests were conducted on all other variables. Results: Though performance on TTCT-V and TTCT-F was worse for both groups during the night shift compared to baseline, the MOD group performed less poorly during treatment than the PBO group on the TTCT-V. A main effect for group (p = .015) was significant as were univariate F tests for subscales of verbal flexibility and originality. The mean decline in flexibility standard scores were -2.62 and -16.38 for MOD and PBO, respectively, and for originality were -1.44 and -9.93 for MOD and PBO, respectively. On the WCST, fewer overall errors were made in MOD (106.1 standard score; p=.005) than PBO (90.9), as well as fewer errors of perseveration (MOD= 110.9, PBO = 93.5; p=.007). MOD made fewer perseverative responses (4.5; p=.043) on SC than PBO (7.5). No group differences were found for TTCT-F, OT, CT, TWF, or LNS. Conclusions: These data suggest that modafinil 200mg reduces the decline in some executive functions during the night shift.
Sleep-deprivation; Sleep-disorders; Circadian-rhythms; Psychomotor-function; Humans; Men; Women; Biological-function; Physiological-effects; Statistical-analysis; Workers; Shift-work; Shift-workers
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UACS, Inc.
Page last reviewed: May 11, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division