ScienceDaily: How shift work affect cognitive functions

How shift work affect cognitive functions
May 17, 2016
Uppsala University
A new study shows that compared to non­shift workers, shift workers needed more time to
complete a test that is frequently used by physicians to screen for cognitive impairment.
However, those who had quit shift work more than five years ago completed the test just
as quick as the non­shift workers.
FULL STORY
A new study from Uppsala University shows that compared to non­shift workers,
shift workers needed more time to complete a test that is frequently used by
physicians to screen for cognitive impairment. However, those who had quit shift
work more than five years ago completed the test just as quick as the non­shift
workers. The findings are published in the journal Neurobiology of Aging.
By utilizing data from around 7000 individuals participating in the Swedish cohort study EpiHealth,
researchers from Uppsala University and Malmö University sought to examine whether shift work history
would be linked to performance. The test that was used is called the “Trail Making Test,” which consists
of two parts. Part A requires participants to connect circles labeled with numbers 1­25 in an ascending
order. In part B, participants must alternate between numbers and letters in an ascending order. Time to
complete these tests has been shown to increase with age.
‘Our results indicate that shift work is linked to poorer performance on a test that is frequently used to
screen for cognitive impairment in humans’, says Christian Benedict, associate professor at the
Department of Neuroscience at Uppsala University and corresponding author of the study.
‘The poorer performance was only observed in current shift workers and those who worked shifts during
the past 5 years. In contrast, no difference was observed between non­shift workers and those who had
quit shift work more than 5 years ago. The latter could suggest that it may take at least 5 years for
previous shift workers to recover brain functions that are relevant to the performance on this test’, says
Christian Benedict