Language performance under sustained work and sleep deprivation conditions

Introduction: Although substantial research has been completed on the effects of sleep deprivation on performance, very little research has focused on language-based tasks. The purpose of the current study was two-fold: 1) to determine the extent to which short-term sleep deprivation affects language performance; and 2) to examine whether relatively short and easy-to-administer "probe" tasks could signal decrements in language performance under sleep deprivation conditions. Methods: There were 38 non-native English-speaking students who were paid to complete a 28-h sleep deprivation study. The participants completed several potential cognitive and vigilance probe tasks and a variety of language-based tasks. Each task was administered four times, once in each testing session during the night (18:30-22:30, 23:00-03:00, 03: 30-07:30, and 08:00-12:00). All tasks were counterbalanced across the testing sessions. Results: Repeated-measures ANOVAs indicated that language tasks that required sustained attention and higher level processing (e.g., reading comprehension) were negatively affected by sleep deprivation, whereas other tasks that relied primarily on more basic language processing (e.g., antonym identification) were not affected. Hierarchical linear modeling analyses assessed how well the probe tasks predicted language performance. These results indicated that performance accuracy and/or speed on many of the probe tasks predicted decrements in language performance. Conclusions: These findings suggest that sustained work conditions and sleep deprivation negatively affect some types of language performance. Moreover, the use of probe tasks indicates that easy-to-administer tasks may be useful to identify when detriments are likely to occur in language-based performance under sleep deprivation conditions.