Effects of NREM sleep instability on cognitive processing

Aricò, Debora; Drago, Valeria; Foster, Paul S.; Heilman, Kenneth M.; Williamson, John; Ferri, Raffaele

doi:10.1016/j.sleep.2010.02.009

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Volume 11, Issue 8 , Pages 791-798, September 2010

Effects of NREM sleep instability on cognitive processing☆

Debora Aricò
- Department of Neurology I.C., Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy
- The first two authors contributed equally to performing this study.
Valeria Drago
- Department of Neurology I.C., Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy
- University of Florida, Department of Neurology, Gainesville, FL, USA
- The first two authors contributed equally to performing this study.
Paul S. Foster
- University of Florida, Department of Neurology, Gainesville, FL, USA
- Middle Tennessee State University, Department of Psychology, Murfreesboro, TN, USA
Kenneth M. Heilman
- University of Florida, Department of Neurology, Gainesville, FL, USA
John Williamson
- University of Florida, Department of Neurology, Gainesville, FL, USA
Raffaele Ferri
- Department of Neurology I.C., Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina, Italy
- Corresponding author. Address: Department of Neurology I.C., Oasi Institute, Via C. Ruggero 73, 94018 Troina, Italy. Tel.: +39 0935 936111; fax: +39 0935 936694.

Received 4 October 2009; received in revised form 13 February 2010; accepted 23 February 2010.

Abstract

Objective

Cyclic alternating pattern (CAP) A1 subtypes, characterized by high-voltage slow waves, are generated by the frontal cortex and are suspected to have a role in cognitive processing during NREM sleep. Conversely, CAP A2 and A3 subtypes are characterized by variable amounts of rapid EEG potentials arising from the parietal–occipital areas and often coincide with arousals. We tested the hypothesis that CAP subtypes differentially correlate with cognitive functions.

Subjects and methods

Eight healthy participants were recruited. Two nocturnal polysomnography studies and a series of neuropsychological tests were obtained in the subjects during the morning and afternoon of the first day and on the morning of the second day.

Results

In agreement with our original hypothesis, we found that CAP A1 subtypes were correlated with better neuropsychological functioning the day after, for verbal fluency, working memory, and both delayed recall and recognition of words. These same neuropsychological test results were found to be negatively correlated with CAP A2 subtypes. CAP A3 subtypes were negatively correlated with the Trial Making test Parts A and B.

Conclusions

The results suggest that CAP A1 might be related to better cognitive functioning, whereas CAP A2 and A3 correlated with worse cognitive functioning. Further studies are needed to better understand how CAP influences cognitive performance, especially frontally-dependent functions and memory.

Keywords: Cyclic alternating pattern, Cognitive functioning, Neuropsychological testing, Sleep instability, Frontal lobe function, Normal sleep