Validation of Perceived Mental Fatigability Using the Pittsburgh Fatigability Scale

Sharon W. Renner, Todd M. Bear, Patrick J. Brown, Stacy L. Andersen, Stephanie Cosentino, Theresa Gmelin, Robert M. Boudreau, Jane A. Cauley, Yujia Qiao, Eleanor M. Simonsick, Nancy W. Glynn

Research output: Contribution to journalArticlepeer-review


Objectives: Establish reliability, concurrent and convergent validity of the Pittsburgh Fatigability Scale (PFS) Mental subscale. Design: Cross-sectional. Setting: Older adults from two University of Pittsburgh registries, Baltimore Longitudinal Study of Aging (BLSA), and Long Life Family Study (LLFS). Participants: PFS Mental subscale validation was conducted using three cohorts: (1) Development Sample (N = 664, 59.1% women, age 74.8 ± 6.4 years, PFS Mental scores 10.3 ± 9.1), (2) Validation Sample I—BLSA (N = 430, 51.9% women, age 74.5 ± 8.2 years, PFS Mental scores 9.4 ± 7.9), and (3) Validation Sample II—LLFS (N = 1,917, 54.5% women, age 72.2 ± 9.3 years, PFS Mental scores 7.5 ± 8.2). Measurements: Development Sample, Validation Sample I—BLSA, and Validation Sample II—LLFS participants self-administered the 10-item Pittsburgh Fatigability Scale. Validation Sample II—LLFS completed cognition measures (Trail Making Tests A and B), depressive symptomatology (Center for Epidemiologic Studies—Depression Scale, CES-D), and global fatigue from two CES-D items. Results: In the Development Sample and Validation Sample I—BLSA, confirmatory factor analysis showed all 10 items loaded on two factors: social and physical activities (fit indices: SRMSR = 0.064, RMSEA = 0.095, CFI = 0.91). PFS Mental scores had strong internal consistency (Cronbach's α = 0.85) and good test-retest reliability (ICC = 0.78). Validation Sample II—LLFS PFS Mental scores demonstrated moderate concurrent and construct validity using Pearson (r) or Spearman (ρ) correlations against measures of cognition (Trail Making Tests A (r = 0.14) and B (r = 0.17) time), depressive symptoms (r = 0.31), and global fatigue (ρ = 0.21). Additionally, the PFS Mental subscale had strong convergent validity, discriminating according to established clinical or cognitive testing cut points, with differences in PFS Mental scores ranging from 3.9 to 7.6 points (all P <.001). All analyses were adjusted for family relatedness, field center, age, sex, and education. Conclusions: The validated PFS Mental subscale may be used in clinical and research settings as a sensitive, one-page self-administered tool of perceived mental fatigability in older adults.

Original languageEnglish (US)
Pages (from-to)1343-1348
Number of pages6
JournalJournal of the American Geriatrics Society
Issue number5
StatePublished - May 2021
Externally publishedYes


  • cognitive performance
  • depressive symptomatology
  • fatigue
  • physical function

ASJC Scopus subject areas

  • Geriatrics and Gerontology


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