The effect of chronotype and time of assessment on cognitive performance

ABSTRACT

Standard cognitive measures are often applied at various times of the day to assess cognitive deficits in patients with neuropsychiatric and neurodegenerative disorders, irrespective of their chronotype. In this study, we aimed to determine whether the subjectively nonpreferred time of an assessment might be a crucial factor in persons with extreme chronotypes. We compared morning (08:00) and evening (20:00) cognitive performance in extreme morning, extreme evening, and intermediate chronotypes determined by the Morningness-Eveningness Questionnaire, supported by actigraphy and peripheral temperature measurement. The assessment sessions were performed in pseudorandom order over two consecutive weekend days. We administered the commonly used test battery for neurocognitive assessment comprised of tasks aimed mainly at attention, processing speed, working memory, and declarative memory. The time of assessment influenced the declarative memory measures, whereas the chronotype-specific differences occurred only in the Stroop colour-naming subtest aimed at processing speed. The observed effects should be considered in routine clinical practice because they might cause misrepresentation of the results obtained during improperly timed cognitive assessment. Our results also point towards similarity of doves and owls in contrast to larks in cognitive performance, suggesting that early morning assessments should also be considered in cases of intermediate chronotypes.

KEYWORDS:

• Chronotype
• morningness
• eveningness
• cognitive performance
• actigraphy
• peripheral temperature

Author contributions

KE is the main corresponding author. She was involved in the study’s preparation and was responsible for data collection and preprocessing as well as writing the manuscript. IF supervised the study and was responsible for the interpretation of the cognitive assessment’s results. KČ, ON, and DUD were involved in the data analysis and the writing of the manuscript. TN and EF were involved in preparing the study and writing the manuscript.

Disclosure statement

The authors do not report any potential conflict of interest.

Statement of ethics

All procedures performed in the study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study. The Ethical Committee of the National Institute of Mental Health approved the study protocol (Klecany, Czech Republic).

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This study was supported mainly by the project of the Charles University Grant Agency number 138217, and partially by the project Nr. LO1611 with a financial support from the MEYS under the NPU I program, and by the program PROGRES Q35 of the Charles University.