Adaptation of performance during a week of simulated night work

Abstract

This study aimed to provide a comparative index of the performance impairment associated with the fatigue levels frequently experienced in workplaces that require night work. To do this, we equated fatigue-related impairment with the impairment resulting from varying levels of alcohol intoxication. Fifteen young individuals participated in two counterbalanced conditions which required them to (1). 'work' seven consecutive 8-h night shifts, and (2). consume an alcoholic beverage at hourly intervals until their blood alcohol concentration (BAC) reached 0.10%. In each condition, performance was measured at hourly intervals using a 10-min psychomotor vigilance task (PVT). Analysis indicated that as BAC increased, performance impairment significantly increased. Similarly, response times significantly increased during the first six simulated night-shifts, and lapse frequency significantly increased during the first two shifts. Equating the two conditions indicated that the first simulated night shift was associated with the greatest degree of performance impairment. In general, the impairment at the end of this shift was greater than that observed at a BAC of 0.10%. During the second and third simulated night shifts, the performance impairment was less than on the first night, but greater than that observed at a BAC of 0.05%. For the final four nights, the performance decrements generally did not exceed those observed at a BAC of 0.05%. This suggests that during a week of consecutive night shifts, adaptation of performance occurs.

Comparative Sensitivity of Outcome Variables of a Software-based Behavioral Sleep Resistance Task

“…Our analysis of the first 10 min of the BSRT challenges show that mean response speed, response variability and the number of 1 or 2 consecutive errors are sensitive to the effects of extended wakefulness. Similar results have been reported manifold with comparable PVT outcome variables (mean RS, SD RS and lapses) [33][34][35][36] . Despite the fact that the analysis was carried out as a proxy for a shorter BSRT, our findings suggest that it may be suitable to assess performance decrements within more time-restricted operational settings.…”

“…Since a primary concern of performance measures is to present analogs of real life, time-on-task should be sufficiently long to allow for proper screening purposes (for a review see Millar 31) ). Nevertheless, performance tasks as short as 10 min, such as the Psychomotor Vigilance Test (PVT) 32) , have also shown to be highly sensitive to various forms of sleep restriction in different environments [33][34][35][36] . Participants subjected to the PVT are required to respond to a visual stimulus (four-digit LED incrementing from 0 to 60 s at 1-ms intervals) presented at variable inter-stimulus intervals by pressing a button.…”

The Relationship between Psychomotor Vigilance Performance and Quality of Life in Obstructive Sleep Apnea

“…Age, AHI, ODI, and CES-D were not significant individual predictors of the SF-36 PCS at any step of the analysis. Step sleep loss (total sleep deprivation, chronic partial sleep restriction, and sleep fragmentation), 47,48 and higher AHI. 45 It is difficult to sort through the implications of the independent effect of PVT performance on health-related QoL even after controlling for apnea severity.…”

Characterizing Recovery of Sleep after Four Successive Night Shifts

“…The Shift Work Committee of the Japan Society for Occupational Health 3) recommended that night shifts should consist of up to at least two or three successive nights in conformity with the guideline put forth by Knauth and Rutenfranz 4) . Some researchers, however, have proposed that performance and alertness improve over a period of successive night shifts 5,6) .…”

“…The computerized test battery consisted of a visual vigilance test (VVT), and subjective assessment of sleepiness and fatigue on a visual analogue scale. The VVT required the participants to press the key corresponding to the numeral (2,4,6,8) presented in the center of the display as quickly and accurately as possible. The stimulus was presented for 5 s and the interstimulus interval randomly varied between 1 and 10 s. Response times longer than 5 s were scored as lapses.…”