International Psychogeriatrics

Research Article

Longitudinal relationships between subjective fatigue, cognitive function, and everyday functioning in old age

Feng Lina1 c1, Ding-Geng Chena2, David E. Vancea3, Karlene K. Balla4 and Mark Mapstonea5

a1 School of Nursing, University of Rochester Medical Center, Rochester, New York, USA

a2 School of Nursing, and Department of Biostatistics and Computational Biology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA

a3 School of Nursing, and Edward R. Roybal Center for Translational Research on Aging and Mobility, University of Alabama at Birmingham, Birmingham, Alabama, USA

a4 Department of Psychology, and Edward R. Roybal Center for Translational Research on Aging and Mobility, University of Alabama at Birmingham, Birmingham, Alabama, USA

a5 Department of Neurology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA

ABSTRACT

Background: The present study examined the prospective relationships between subjective fatigue, cognitive function, and everyday functioning.

Methods: A cohort study with secondary data analysis was conducted using data from 2,781 community-dwelling older adults without dementia who were enrolled to participate in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) randomized intervention trial. Measures included demographic and health information at baseline, and annual assessments of subjective fatigue, cognitive function (i.e. speed of processing, memory, and reasoning), and everyday functioning (i.e. everyday speed and everyday problem-solving) over five years.

Results: Four distinct classes of subjective fatigue were identified using growth mixture modeling: one group complaining fatigue “some of the time” at baseline but “most of the time” at five-year follow-up (increased fatigue), one complaining fatigue “a good bit of the time” constantly over time (persistent fatigue), one complaining fatigue “most of the time” at baseline but “some of the time” at five-year follow-up (decreased fatigue), and the fourth complaining fatigue “some of the time” constantly over time (persistent energy). All domains of cognitive function and everyday functioning declined significantly over five years; and the decline rates, but not the baseline levels, differed by the latent class of subjective fatigue. Except for the decreased fatigue class, there were different degrees of significant associations between the decline rates of subjective fatigue and all domains of cognitive function and everyday functioning in other classes of subjective fatigue.

Conclusion: Future interventions should address subjective fatigue when managing cognitive and functional abilities in community-dwelling older adults.

(Received July 26 2012)

(Reviewed September 07 2012)

(Revised September 12 2012)

(Accepted September 19 2012)

(Online publication October 19 2012)

Key words:

  • subjective fatigue;
  • cognition;
  • everyday functioning;
  • ACTIVE

Correspondence:

c1 Correspondence should be addressed to: Feng Lin, School of Nursing, University of Rochester Medical Center, Helen Wood Hall, 601 Elmwood Avenue, Rochester, NY 14642. Phone: +585-276-6002; Fax: +585-273-1270. Email: vankee_lin@urmc.rochester.edu.