Time of Day Affects Episodic Memory in Older Adults*

*For the ADAPT Research Group.

ABSTRACT

The neuropsychological test scores of 2,030 cognitively normal older adults were examined to evaluate performance patterns as they related to time of day (TOD) at which testing was initiated. Multiple regression analyses were used to examine the association of TOD with scores on seven neuropsychological tests used in the clinical evaluation of dementia. Episodic memory performance was significantly related to TOD, while memory span and verbal fluency were not. Best performance occurred during early morning hours and late afternoon; worst performance occurred mid-day (i.e., noon). These findings may have implications for clinical assessment, the design of research on dementia, and the daily functioning of older adults.

Keywords:

• Episodic memory
• Aging
• Dementia
• Circadian rhythms
• Performance variability

ACKNOWLEDGEMENTS

The authors wish to thank Suzanne Craft, Ph.D. and Patricia Boyle, Ph.D. for their many helpful and insightful comments about this manuscript. This work was supported by a cooperative agreement from the National Institute on Aging to the University of Washington, Seattle, Washington (U01AG15477). NIA collaborators participated in the design and conduct of the study. Naproxen sodium and matching placebo were supplied by Bayer Healthcare, and celecoxib and matching placebo were supplied by Pfizer, Inc. Dr Brandt receives royalties on sales of the Hopkins Verbal Learning Test–Revised.

ADAPT Steering Committee (responsibilities: study design and conduct, interpretation and review of results)

Resource center representatives/Study officers:

John Breitner, MD, MPH (Study Chair), Veteran Affairs Puget Sound Health Care System and University of Washington School of Medicine, Seattle

Neil Buckholtz, PhD (Project Officer), National Institute on Aging, Bethesda

Barbara Martin, PhD (Coordinating Center Deputy Director), Johns Hopkins Bloomberg School of Public Health, Baltimore

Curtis Meinert, PhD (Coordinating Center Director), Johns Hopkins Bloomberg School of Public Health, Baltimore

Susan Molchan, MD (Project Officer), National Institute on Aging, Bethesda

Field site directors:

Suzanne Craft, PhD, Veteran Affairs Puget Sound Health Care System and University of Washington School of Medicine, Seattle

Robert Green, MD, Boston University School of Medicine, Boston

Constantine Lyketsos, MD, MHS, Johns Hopkins School of Medicine, Baltimore

Michael Mullan, MD, PhD, The Roskamp Institute Memory Clinic, Tampa

Marwan Sabbagh, MD, Sun Health Research Institute, Sun City, AZ

Pierre Tariot, MD, University of Rochester School of Medicine, Rochester

Other voting members:

Jason Brandt, PhD, Johns Hopkins School of Medicine, Baltimore

Steven Piantadosi, MD, PhD, Johns Hopkins School of Medicine, Baltimore

Collaborators:

Denis Evans, MD, Rush-Presbyterian-St. Luke's Medical Center, Chicago

Kathleen Welsh-Bohmer, PhD, Duke University Medical Center, Durham

Staff:

Janette Negele, Veteran Affairs Puget Sound Health Care System, Seattle

Bonnie Piantadosi, MSW, MPH, Johns Hopkins Bloomberg School of Public Health, Baltimore

Consultants:

Themos Dassopoulos, MD, Johns Hopkins School of Medicine, Baltimore

Claudia Kawas, MD, University of California Irvine, Irvine

Leon Thal, MD, University of California San Diego, La Jolla

Andrew Whelton, MD, Hunt Valley, MD

Research group

Resource centers (responsibilities: study administration):

Chairman's Office, Veteran Affairs Puget Sound Health Care System, Seattle, WA: John C. S. Breitner, MD, MPH, Chairman; Janette Negele, Coordinator; Elizabeth Aigbe, MS; Jill Dorje; Brenna Cholerton, PhD

Coordinating Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD: Curtis L. Meinert, PhD, Director; Barbara K. Martin, PhD, Deputy Director; Bonnie Piantadosi, MSW, MPH, Coordinator; Robert Casper, MS; Michele Donithan, MHS; Hsu-Tai Liu, MD, MPH; Steven Piantadosi, MD, PhD; Anne V. Shanklin, MA, CCRP

Project Office, National Institute on Aging, Bethesda, MD: Neil Buckholtz, PhD, Project Officer; Susan Molchan, MD

Field sites (responsibilities: data collection):

Johns Hopkins School of Medicine, Baltimore, MD: Constantine G. Lyketsos, MD, MHS, Director; Martin Steinberg, MD, Associate Director; Jason Brandt, PhD, Neuropsychologist; Julia J. Pedroso, RN, MA, Coordinator; Alyssa Bergey; Themos Dassopoulos, MD; Melanie Dieter, MA; Carol Gogel, RN; Chiadi Onyike, MD; Lynn Smith; Veronica Wilson-Sturdivant; Nadine Yoritomo, RN

Boston University School of Medicine, Boston, MA: Robert C. Green, MD, Director; Sanford Auerbach, MD, Associate Director; Patricia Boyle, PhD, Neuropsychologist; Mary-Tara Roth, RN, MSN, MPH, Coordinator; Jane Mwicigi, MD, MPH, Coordinator; Lorraine Baldwin; Margaret Brickley, MS, RN, NP; Patrick Compton, RN; Debra Hanna, RN, BC, MPH; Sylvia Lambrechts; Janet Nafissi, MSN, APRN, BC; Andreja Packard, MD, PhD; Robert Stern, PhD; Mayuri Thakuria, MD, MPH

University of Rochester School of Medicine, Rochester, NY: Pierre N. Tariot, MD, Director; Saleem Ismail, MD, Associate Director; J. Michael Ryan, MD, Associate Director (previous); Robin Henderson-Logan, PhD, ABPP-cn, Neuropsychologist; Colleen McCallum, MSW, Coordinator; Suzanne Decker; Laura Jakimovick, RN, MS; Kara Jones, RN; Arlene Pustalka, RN; Susan Salem-Spencer, RN, MS; Asa Widman

Veteran Affairs Puget Sound Health Care System and University of Washington School of Medicine, Seattle, WA: Suzanne Craft, PhD, Director; Mark Fishel, MD, Associate Director; Laura Baker, PhD, Neuropsychologist; Kathleen Nelson, RN, Coordinator; Susan Bigda, RN; Yoshie Biro; Ruth Boucher, RN; Deborah Dahl, RN; Nickolas Dasher; Edward DeVita, MD; Grace Garrett; Austin Hamm; Jeff Lindsey; Laura Sissons-Ross

Sun Health Research Institute, Sun City, AZ: Marwan Sabbagh, MD, FAAN, Director; Joseph Rogers, PhD, Associate Director; Donald Connor, PhD, PhD, Neuropsychologist; Carolyn Liebsack, RN, BSN, CCRC, Coordinator; Joanne Ciemo, MD; Kathryn Davis; Theresa Hicksenhiser, LPN; Sherry Johnson-Traver; Healther Kolody; Lisa Royer, RN; Nina Silverberg, PhD; Deborah Tweedy, RN, MSN, CNP

The Roskamp Institute Memory Clinic, Tampa, FL: Michael Mullan, MBBS, PhD, Director; Timothy Crowell, PsyD, Associate Director, Neuropsychologist; Julia Parrish, LPN, Coordinator; Theavy Chea; Scott Creamer; Melody Brooks Jayne, MD; Antoinette Oliver, MA; Summer Price, MA; Joseph Zolton, ERT

Collaborators (responsibilities: study design and administration):

Denis Evans, MD; Kathleen Welsh-Bohmer, PhD

Consultants:

Claudia Kawas, MD; Leon Thal, MD

Notes

*For the ADAPT Research Group.